JPH10272945A - Front and rear wheel drive vehicles - Google Patents

Abstract

(57) [Problem] To provide a front-wheel drive vehicle capable of smoothly and quickly switching from a two-wheel drive state to a front-wheel drive state. SOLUTION: A first transmission member for transmitting a driving force to a first wheel side, a second transmission member connected to the first transmission member via a connecting means and transmitting the driving force to a second wheel side, Clutch means for connecting the first transmission member and the second transmission member, drive switching instruction means for outputting a switching signal for switching the driving state of the vehicle between the two-wheel driving state and the front and rear wheel driving state, and drive switching instruction means Connection switching means (S442, S444) for switching the connection means between the connection state and the non-connection state based on the switching signal from
And a switching signal from the two-wheel drive state to the front and rear wheel drive state is output by the drive switching instruction means, and the connection switching operation of the first transmission member and the second transmission member of the connection means by the connection switching means is performed. Up to clutch control means (S434) for controlling engagement of the clutch means.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front and rear wheel drive vehicle in which both front wheels and rear wheels are driven, and more particularly to drive control of a four-wheel drive vehicle having a transfer device.

[0002]

2. Related Background Art In a front-rear wheel drive vehicle such as a four-wheel drive vehicle, the driving force of an engine is normally distributed to a front wheel side and a rear wheel side as disclosed in Japanese Patent Publication No. 8-25402. A transfer device having a differential device is provided. In this type of transfer device, the drive mode can be switched between two-wheel drive (2WD), full-time four-wheel drive (full-time 4WD), and direct-coupled four-wheel drive (direct-coupled 4WD) via a switching mechanism. ing. Specifically, a desired drive mode is obtained by gripping a plurality of clutch gears with a coupling sleeve.

However, in such a transfer apparatus, when the drive mode is switched from two-wheel drive (2WD) to full-time four-wheel drive (full-time 4WD) or direct-coupled four-wheel drive (direct-coupled 4WD), that is, a plurality of clutches are used. When changing gears, the clutch gears to be engaged may not always be synchronized depending on the running state of the vehicle. As described above, if the clutch gears are not synchronized with each other, the coupling sleeve does not operate satisfactorily, and there is a possibility that the clutch gear cannot be re-engaged. Further, there is a possibility that abnormal noise or the like is generated due to the collision between the coupling sleeve and the clutch gear or the clutch gear is damaged.

In order to solve such a problem, a synchro mechanism is usually used to synchronize clutch gears that contribute to engagement.

[0005]

However, even if the synchro mechanism is used in this way, for example, when the input torque from the engine to the transfer device is large, it is attempted to switch the drive mode of the transfer device. However, since the coupling sleeve cannot be moved, the drive mode cannot be switched, and the vehicle must be driven in a state that does not adapt to the driving state of the vehicle or the driver's intention. At this time, if the drive mode is forcibly switched, abnormal noise may be generated or the clutch gear may be damaged. In addition, when the rotational speed difference between the front wheel and the rear wheel is large, it is still difficult to quickly synchronize the clutch gears with each other. There is.

In particular, when the vehicle enters a rough road, the driving mode is changed from two-wheel drive (2WD) to full-time four-wheel drive (full-time 4WD) or direct-coupled four-wheel drive (direct-coupled four-wheel drive).
In the case where it is desired to switch to WD) or the like, it is not preferable to take time to switch the drive mode because it leads to deterioration of the running performance of the vehicle. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a front-wheel drive vehicle capable of smoothly and quickly realizing switching of a drive mode from two-wheel drive to front-rear wheel drive without abnormal noise or the like. To provide.

[0007]

In order to achieve the above object, according to the first aspect of the present invention, when a switching signal is output from the drive switching command means, the first transmission member and the second transmission member are connected based on the switching signal. The connecting means to be connected is switched between the connected state and the non-connected state by the connection switching means. The drive switching command means switches the two-wheel drive state by the first wheel to the front and rear wheel drive state by the first and second wheels. When the switching signal is output, the connection switching means switches the connection means to the first state.
Until the transmission member and the second transmission member are connected, engagement of the clutch unit is controlled by the clutch control unit.

[0008] Thus, from the time before the connection switching operation between the first transmission member and the second transmission member of the connection means by the connection switching means is actually performed, the first connection member is engaged by the clutch means.
The driving force is transmitted from the transmitting member to the second transmitting member, the driving force is rapidly transmitted to the front and rear wheels, and then the connection switching operation of the connecting means is performed, so that the desired driving mode is set. Achieved.

According to the second aspect of the present invention, when the driving wheel switching signal is output from the driving switching command means, the first connection means for connecting the second output element and the third transmission member is connected based on the output signal. Means for switching between the connected state and the non-connected state. When the second connecting means is in the connected state, the drive switching command means changes the two-wheel drive state by the first wheel to the front and rear by the first and second wheels. When the drive wheel switching signal to the wheel drive state is output, the clutch control means controls the engagement of the clutch means until the first connection means is connected by the connection switching means.

[0010] Thus, the input element or the first output is provided by the engagement of the clutch means from the time before the connection switching operation between the second output element of the first connection means and the third transmission member by the connection switching means is actually performed. The driving force is transmitted from the element to the third transmitting member, the driving force is quickly transmitted to the front and rear wheels, and then the connection switching operation of the first connecting means is performed, so that the desired driving mode is achieved. Is achieved.

According to the third aspect of the present invention, when the direct connection switching signal is output from the drive switching command means, the second connection means is switched between the connected state and the non-connected state based on the signal. When the switching signal from the non-direct connection state to the direct connection state of the differential device is output by the drive switching instruction means while the connection means is in the connection state, the connection switching means until the second connection means is connected. The engagement of the clutch means is controlled by the clutch control means.

Thus, from the point before the connection switching operation of the second connection means by the connection switching means is actually performed, the differential of the differential device is limited by the engagement of the clutch means so that the front-rear operation is performed in a state close to the direct connection state. The driving force is transmitted to the wheels, and the differential between the front and rear wheels is quickly limited. Then, the connection switching operation of the second connection means is performed, whereby the desired drive mode is achieved.

According to the fourth aspect of the present invention, there is provided a rotational speed difference between the front and rear wheels, that is, between the first transmission member and the second transmission member (claim 1) or between the second output element and the third transmission member (claim 2). ), Or the engagement of the clutch means is appropriately controlled in accordance with the magnitude of the rotational speed difference between the elements connected by the second connection means (Claim 3). Synchronization with the transmission member, between the second output element and the third transmission member, or between elements connected by the second connection means is quickly realized.

According to the fifth aspect of the present invention, when the connection determining means determines that the connection is possible, the first connecting means or the second connecting means is switched to the connected state. Until the determination is made, the engagement of the clutch means is controlled by the clutch control means. Thereby, the first connection means or the second connection means by the connection switching means is provided.
The transmission of the driving force from the input element or the first output element to the third transmission member, or the differential limitation of the differential device, is rapidly performed by the engagement of the clutch means before the connection switching operation of the connection means is actually performed. After that, the connection is determined to be possible by the connection determining means and the connection switching operation is performed, whereby the connection switching operation is smoothly realized without abnormal noise or the like, and a desired drive mode is achieved.

At this time, for example, the connection determining means
It is preferable to include a front and rear wheel rotation speed difference detecting means for detecting a front and rear wheel rotation speed difference, and determine that connection is possible when the front and rear wheel rotation speed difference is smaller than a predetermined value. In this case, when the front and rear wheel rotation speed difference is larger than a predetermined value, the connection between the second output element and the third transmission member or the connection between the members connected by the second connection means cannot be accurately connected. Is determined,
Therefore, the connection switching operation of the first connecting means and the second connecting means is suitably prohibited, and the damage of the first connecting means and the second connecting means is prevented.

Also, for example, the connection determining means may include a low-speed turning state detecting means for detecting a low-speed turning state, and when the low-speed turning state is detected, it may be determined that connection is impossible.
In this case, when the vehicle is turning at a low speed at a large steering angle, the connection between the second output element and the third transmission member or the connection between the members connected by the second connection means is not properly connected. It is determined that the connection is possible, and therefore, the connection switching operation of the first connection unit and the second connection unit is suitably prohibited, and the damage of the first connection unit and the second connection unit is prevented.

Further, according to the present invention, when the input torque is smaller than the specified value, it is determined that the first connection means or the second connection means can be connected. When a large driving force load is applied to the input element, the first output element, the second output element, and the third transmission member of the apparatus, it is determined that the connection cannot be accurately made, and therefore the first connection means and the second connection means The connection switching operation of the first connection means and the second connection means is prevented from being broken.

Preferably, the connection determining means has a vehicle speed detecting means for detecting a vehicle speed, and the specified value is set to a larger value as the vehicle speed is higher.
In this case, the input torque generally tends to increase with an increase in the vehicle speed, and by changing the specified value accordingly, the damage of the first connecting means and the second connecting means can be more effectively prevented. Is done.

According to the invention of claim 7, when the switching signal is output from the drive switching command means, the third connection means is switched between the connected state and the non-connected state by the connection switching means based on the switching signal. When the switching signal from the non-direct connection state to the direct connection state of the differential device is output by the drive switching command means, the clutch control means engages the clutch means until the third connection means is connected by the connection switching means. Controlled.

As a result, the differential of the differential device is limited by the engagement of the clutch means from the time before the connection switching operation of the third connection means is actually performed by the connection switching means, so that the front-rear operation is quickly performed. A desired drive mode is achieved by transmitting the same driving force to the wheels and then performing the connection switching operation of the third connection means.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS First, a first embodiment (corresponding to claim 2) will be described. Referring to FIG. 1, there is schematically shown a four-wheel drive (front and rear wheel drive) vehicle of a front engine rear wheel drive (FR) type, and FIG. 2 shows a control block diagram thereof. Referring to these drawings, a four-wheel drive vehicle (front and rear wheel drive vehicle) to which the present invention is applied
Will be described.

As shown in FIG. 1, this vehicle has an engine 2
The engine 2 is connected to a transfer device 6 for 4WD via a transmission 4, that is, an input shaft 8 of the transfer device 6. Although details of the transfer device 6 will be described later, the transfer device 6 includes a rear wheel output shaft 10 and a front wheel transfer sprocket 1 to which the driving force of the input shaft 8 is transmitted.
2 and a rear wheel side output shaft 10 is connected to a rear wheel differential device (rear wheel differential) 1 via a rear propeller shaft.
4 is connected. A pair of left and right rear axles extend from the rear wheel differential 14, and left and right rear wheels RW (first wheels) are connected to these rear axles, respectively. On the other hand, a front propeller shaft 16 extends from the transfer sprocket 12, and the front propeller shaft 16 is connected to a front wheel differential device (front wheel differential) 18.
A pair of left and right front axles extend from the front wheel differential 18, and left and right front wheels FW (second wheels) are respectively connected to these front axles.

Referring to FIG. 1, the right front axle is divided in the middle thereof, and a freewheel hub mechanism (HAB) 19 is provided in the divided portion. In the freewheel hub mechanism 19, the clutch gear 20,
22 is attached. In the state shown in FIG. 1, the clutch gears 20 and 22 are mutually connected by a coupling sleeve 24. That is, the coupling sleeve 24 has internal teeth formed on its inner peripheral surface which can be engaged with the clutch gears 20 and 22, and the internal teeth are formed on the clutch gears 20 and 22.
22 are engaged with each other. In this case, the divided right front axle can rotate integrally.

The coupling sleeve 24 is slidably supported by a support member (not shown) on the vehicle body side in the axial direction of the right front axle. The fork tip of the shift fork 26 is fitted in the fork groove of the coupling sleeve 24, and the base end of the shift fork 26 is connected to the output rod 30 of the vacuum actuator 28. The vacuum actuator 28 includes a diaphragm that partitions the inside of the housing into a negative pressure chamber 32 and an atmosphere chamber.
The output rod 30 is connected to this diaphragm.
Atmospheric pressure or negative pressure can be selectively supplied to the negative pressure chamber 32 by an electromagnetic switching valve (not shown), and a return spring 34 is accommodated in the negative pressure chamber 32. Negative pressure chamber 3
2 is supplied with air, the return spring 34 urges the output rod 30 in one direction through the diaphragm, and the coupling sleeve 24 is locked in the normal lock (LOC).
K) position, that is, a position where the clutch gears 20, 22 are interconnected. In contrast, the negative pressure chamber 32
Is supplied to the diaphragm, the negative pressure pulls the diaphragm against the urging force of the return spring 34 and pushes the output rod 30 to the left as viewed in FIG. Therefore, the coupling sleeve 24 is free (FRE) from the lock (LOCK) position.
E), the right front wheel FW is separated from the front wheel differential 18 as a result of disconnection between the clutch gears 20 and 22. A negative pressure is supplied to the negative pressure chamber 32 of the vacuum actuator 28 from the intake system of the engine 2 via the above-described electromagnetic switching valve.

In the figure, reference numeral 25 denotes a freewheel hub engagement switch for detecting the state of the freewheel hub mechanism 19, that is, the locked (LOCK) state and the free (FREE) state. Next, the transfer device will be described. Referring to FIG. 3, the actual structure of the transfer device 6 is shown in cross section. Hereinafter, the structure of the transfer device 6 according to the present invention will be described with reference to FIG.

The transfer device 6 has an input shaft 8 connected to the output shaft of the transmission 4 and an intermediate shaft 36 located coaxially with the input shaft 8. Input shaft 8 and intermediate shaft 3
Numerals 6 are rotatably supported on the transfer case side of the transfer device 6 independently of each other. A subtransmission mechanism 38 is arranged between the input shaft 8 and the intermediate shaft 36. More specifically, the subtransmission mechanism 38 has a pair of clutch gears 40 and 42,
Reference numerals 0 and 42 are attached to the ends of the input shaft 8 and the intermediate shaft 36 that face each other. Clutch gear 40,
Reference numeral 42 rotates integrally with the input shaft 8 and the intermediate shaft 36, respectively. Further, the intermediate shaft 36 rotatably supports the clutch gear 44, and the clutch gear 44 is provided with a low gear 46 coaxially and integrally. The low gear 46 meshes with a counter gear 48, and the counter gear 48 is attached to one end of a counter shaft 50. The counter shaft 50 is arranged in parallel with the input shaft 8 and the intermediate shaft 36, and is rotatably supported on the transfer case side. The other end of the counter shaft 50 is connected to the input shaft 8 via a pair of gears 52 and 54.
Therefore, the rotation of the input shaft 8 is transmitted to the low gear 46 via the pair of gears 52, 54, the counter shaft 50, and the counter gear 48. At this time, since the number of teeth of the low gear 46 is set to be larger than the number of teeth of the counter gear 48, the low gear 46 is rotated at a lower speed than the rotation of the counter shaft 50. Therefore, the rotation of the input shaft 8 is
2. The speed can be reduced and transmitted to the intermediate shaft 36 via the counter shaft 50 and the counter gear 48.

Outside the clutch gears 40, 42, and 44, a coupling sleeve 56 having the same structure as the above-described coupling sleeve 24 is disposed. Are slidably supported along the line. In the state shown in FIGS. 1 and 3, the coupling sleeve 56 is
The clutch gears 40 and 42 are engaged with each other (high gear position). In this case, the input shaft 8 is connected to the intermediate shaft 36 via the clutch gears 40 and 42, and the rotation of the input shaft 8 is directly transmitted to the intermediate shaft 36. On the other hand, the coupling sleeve 5
When the gear 6 is shifted from the high gear position to the clutch gear 44 side in FIG. 1, the coupling sleeve 56 connects the clutch gears 42 and 44 to each other (low gear position).
It is positioned in. That is, the coupling sleeve 56
In the low gear position, while the connection between the clutch gears 40 and 42 is cut off, the clutch gears 42 and 44 are engaged with each other, and the clutch gears 42 and 44 are mutually connected. In this case, the rotation of the input shaft 8 is transmitted at a reduced speed from the counter shaft 50 side to the intermediate shaft 36 via the counter gear 48, the low gear 46, the clutch gear 44, the coupling sleeve 56, and the clutch gear 42, as described above. Is done.

A shift fork 58 is engaged with the coupling sleeve 56, and the shift fork 58 can be reciprocated by an electric shift actuator 60. The shift actuator 60 will be described later. The intermediate shaft 36 has a center differential device (center differential: differential device) 62 composed of a planetary gear mechanism.
And is connected to the rear wheel output shaft 10 through the power supply. More specifically, the center differential 62 includes a differential case (first output element) 64 composed of a ring gear, a sun gear 68 that meshes with the differential case 64 via a plurality of planetary gears 66, and a carrier (input element) that rotatably supports the planetary gears 66. 70
The other end of the intermediate shaft 36 is coaxially connected to the carrier 70. And differential case 6
4, a rear wheel output shaft 10 extends coaxially. The sun gear 68 of the center differential 62 has an inner sleeve shaft (second
The inner sleeve shaft 72 is rotatably supported on the intermediate shaft 36. The center differential 62 can transmit the rotation input from the intermediate shaft 36, that is, the driving force, to the inner sleeve shaft 72 which is an output member to the front wheel FW and the differential case 64 which is an output member to the rear wheel RW. In this case, The gear ratio of the center differential 62 is as follows.
% And the rear wheel RW side are set to 70%.

An inner sleeve shaft 72 of the center differential 62 extends toward the input shaft 8 and has a clutch gear 74 at the other end.
Is attached. Further, the inner sleeve shaft 72
An outer sleeve shaft (third transmission member) 76 is rotatably supported on the upper side, and the outer sleeve shaft 76 is connected to the clutch gear 74 of the inner sleeve shaft 72 from the center differential 62 side.
Extending towards. A clutch gear 78 is formed at an end of the outer sleeve shaft 76 located on the clutch gear 74 side, and the clutch gear 74 of the inner sleeve shaft 72 is sandwiched between the intermediate shaft 36 and the clutch gear 78. A clutch gear 80 is mounted.

Outside the clutch gears 74, 78, 80, a coupling sleeve (first connecting means and second connecting means) 82 is disposed, and the coupling sleeve 8 is provided.
2 is supported slidably in the axial direction of the intermediate shaft 36. The coupling sleeve 82 has a circumferential groove on its inner peripheral surface, so that its internal teeth have two parts 82 as shown in FIG.
a and 82b.

Here, the coupling sleeve 8 is used.
2 has two functions of a first connecting means for connecting the clutch gears 74 and 78 to each other and a second connecting means for connecting the clutch gears 74 and 80 to each other, but the coupling sleeve 82 is divided. The first connecting means and the second connecting means may be individually provided. When in the state shown in FIG. 1 and FIG.
The first connecting means 2 meshes with the clutch gears 74 and 78 and positions the clutch gears 74 and 78 at a position where they are connected to each other (full-time 4WD position, non-direct connection state). At this time, the clutch gear 80 is located in the above-mentioned circumferential groove of the coupling sleeve 82, and the engagement between the clutch gear 80 and the coupling sleeve 82 is released. When the coupling sleeve 82 shifts from the full-time 4WD position to the clutch gear 80 side and the second connecting portion is positioned at a position (2WD position) where the second connecting means meshes with the clutch gears 74 and 80, the clutch gears 74 and 80 are connected to each other. Meanwhile, the connection between the clutch gears 74 and 78 is disconnected. On the other hand, when the coupling sleeve 82 is shifted from the full-time 4WD position in the reverse direction and is positioned at the position where it engages with all of the clutch gears 74, 78, and 80 at the same time (direct connection 4WD position, direct connection state), all of them are mutually connected. Connect to The coupling sleeve 82 is also engaged with the shift fork 84, and the shift fork 84 is reciprocated by the shift actuator (connection switching means) 60.

The front wheel F is attached to the outer sleeve shaft 76 described above.
An output sprocket 85 for transmitting the driving force to the W side is attached, and a drive chain 86 is looped between the output sprocket 85 and the transfer sprocket 12 described above. Further, a hydraulic multi-plate clutch (clutch means) 88 is disposed between the outer sleeve shaft 76 and the differential case 64 of the center differential 62, and the hydraulic multi-plate clutch 88 connects to a pressure regulating passage 190 (see FIG. 3). It is hydraulically connected to a valve body 90 having a built-in electromagnetic valve (not shown). Therefore, the hydraulic multi-plate clutch 88 disconnects the connection between the outer sleeve shaft 76 and the differential case 64 in accordance with the hydraulic pressure supplied from the valve body 90, that is, the magnitude of the clutch pressure, and also controls the differential case 64
It is possible to vary the torque transmission from the shaft to the outer sleeve shaft 76. The valve body 90 has an oil pump 9 connected to the end of the above-described counter shaft 50 and generating hydraulic pressure by rotation of the counter shaft 50.
2 is hydraulically connected via lines 127 and 129 (see FIG. 3), whereby the hydraulic pressure is increased according to the degree of opening and closing of the electromagnetic valve of the valve body 90 by the hydraulic multi-plate clutch 88.
It can be supplied to

Here, the shift actuator 60 will be described. As shown in FIG.
Numeral 0 is provided with a motor unit 202, and the motor unit 202 has an electric motor 204 rotatable in normal and reverse directions in a unit case. The electric motor 204 of the shift actuator 60 is electrically connected to an electronic control unit (ECU) 94 as shown in FIG.
In response to the control signal from 94, the drive and the rotation direction are controlled. The output shaft of the electric motor 204 has a pinion 2
06 is attached, and the pinion 206 is mounted on the rack 2
08. The rack 208 extends in parallel with the axis of the transfer device 6 described above, and is slidably supported by the unit case.

The rack 208 is provided with the motor unit 2
02 and is integrally connected to the main shift rail 210. In the vicinity of the main shift rail 210, a pair of sub shift rails 212 and 214 are arranged in parallel with the main shift rail 210. These sub shift rails 212, 214
Are coaxial with each other and are spaced apart by a predetermined distance. The shift fork 58 described above is attached to one of the sub shift rails 212, and the shift fork 84 is attached to the other sub shift rail 214. The main shift rail 210 and the pair of sub shift rails 212 and 214 are slidably supported by a plurality of rail receivers (not shown) in the transfer case of the transfer device 6.

A pinion 232 and a pinion 232 are provided between the main shift rail 210 and the sub shift rails 212 and 214, respectively.
234 are arranged, and these pinions 232, 23
4 is rotatably supported by a bearing (not shown) provided on the rail receiver. A rack portion 236 is formed on the sub-shift rail 212, and the rack portion 236 always meshes with the pinion 232. Similarly, a rack portion 238 is formed on the sub shift rail 214, and the rack portion 238 is also always engaged with the pinion 234. On the other hand, a pair of rack portions 240 and 242 are formed on the main shift rail 210 so as to cooperate with the pinions 232 and 234, respectively, and are separated in the axial direction of the main shift rail 210. In addition,
The rack portions 240 and 242 may be one continuous rack portion having rack teeth formed between them.

In the state shown in FIG. 1 (full-time 4WD state), the rack portion 240 of the main shift rail 210 is not engaged with the pinion 232, and is located below the pinion 232 in FIG. On the other hand, the rack portion 242 is engaged with the pinion 234 at the center thereof as seen in FIG. As shown in FIG. 2, various sensors, switches, indicators, and the like are electrically connected to the input side of the ECU 94. The sensors include a front-rear G sensor 96 for detecting the front-rear acceleration (front-rear G) Gx of the vehicle body, a throttle opening sensor 98 for detecting the opening (throttle opening) θTH of a throttle valve in the engine 2, and a steering wheel angle θH. Angle sensor 100 and rotational speed sensors 102, 104, 10 for detecting
6 and others.

On the other hand, the output side of the ECU 94 is connected to devices such as an electromagnetic valve of the valve body 90, an electromagnetic switching valve for the vacuum actuator 28, and an electric motor 204 of the shift actuator 60.
The operation of these devices is controlled by the ECU 94 in accordance with signals from the various sensors and the like. The rotation speed sensor 102 will be described. As shown in FIGS. 1 and 3, a ring member 120 is provided concentrically on the outer side of the rear wheel output shaft 10 and formed with a screw gear 122 on the outer peripheral surface. The rotation speed sensor 102 detects the rotation speed of the ring member 120 that rotates integrally with the rear wheel output shaft 10. More specifically, the rotation speed sensor 102 is further provided with a detection shaft on which the screw gear 124 is formed and a ring multi-pole magnet (not shown) coaxial with the detection shaft and capable of synchronous rotation. The sensor 102 includes the screw gear 122 and the screw gear 124.
The rotation of the ring multi-pole magnet, which rotates synchronously with the detection shaft due to meshing with the detection shaft, is detected by a magnetoresistive element, and this detection signal is output to the ECU 94, whereby the rear wheel output shaft 1
0, that is, the rotational speed of the rear propeller shaft can be detected.

Further, the rotation speed sensor 104 detects the right front wheel F
The rotational speed of the right front wheel FW is detected from the rotational speed of the detection gear 110 attached to the right front axle near W, and the rotational speed sensor 106 outputs the rotational speed of the transfer device 6 from the rotational speed of the transfer sprocket 12, that is, It detects the rotation speed of the front propeller shaft 16 (see FIG. 1).

The switches connected to the ECU 94 include a brake switch 11 provided on a brake pedal.
2. A transfer position switch (T / F position switch) 114 (see FIG. 1) for detecting the operation state of the shift actuator 60, a drive mode changeover switch 11
5. There are an inhibitor switch 108 for detecting the selected position of the transmission 4 (a parking range, a neutral range, a drive range, etc.), the freewheel hub engage switch 25, and the like. Drive mode switch 11
Reference numeral 5 denotes a rotary switch for switching the drive mode of the manual transfer device 6 disposed on the instrument panel in the passenger compartment, a 2H position indicating 2WD, an AUTO position indicating auto mode, and a 4H position indicating full time 4WD. 4HLc indicating the direct connection 4WD at the high gear position, ie, the high direct connection 4WD
4WD at position and low gear position, ie low direct connection 4
It has five switching positions Psw of the 4LLc position indicating WD, and outputs a command signal corresponding to the switching positions to the EUC 94.
Further, as shown in FIG. 2, a 4WD indicator 116 is incorporated in the instrument panel near the drive mode changeover switch 115, and the 4WD indicator 116 is a transfer device corresponding to the drive state detected by the transfer position switch 114. 6 drive modes can be displayed.

Further, the output information of the engine 2 is also supplied to the ECU 94, and the engine output information is calculated based on the rotation speed Ne of the engine 2, the throttle opening θTH, the fuel supply amount, and the like. . Hereinafter, the transfer device 6 and the freewheel hub mechanism (HAB) 1 of the four-wheel drive vehicle (front and rear wheel drive vehicle) configured as described above.
9 control procedure, ie 2WD, full-time 4W
The control procedure of drive switching control between D, high direct connection 4WD, and low direct connection 4WD will be described with reference to FIGS.

FIGS. 4 to 6 are flowcharts showing the main routine of the drive switching control, and the following description will be made along the main routine. In step S2, first,
Initialize various parameter values, that is, initialize. Then, in step S4, it is determined whether or not the execution cycle timer TMA of the routine has reached a predetermined cycle TA (for example, a value corresponding to 16 msec). If the result of this determination is false (No) and has not yet reached the predetermined period TA, the execution period timer TMA is counted up in step S5, and waits for the execution period timer TMA to reach the predetermined period TA. On the other hand, when the determination result is true (Yes) and the predetermined period TA has been reached, the process proceeds to step S6, where the input information from the various sensors is fetched.

In the next step S8, it is determined whether or not the switching position Psw of the drive mode switch 115 is at the 2H position. When the determination result is true (Yes) and the switching position Psw is the 2H position (Psw = 2H), the process proceeds to step S10. In step S10, the drive mode based on the switching position Psw, that is, the drive mode command is sent to the 2WD mode (MODE
= 2H) and the select mode is stored as a manual mode (SELECT = MANU). In the select mode, when the switching position Psw is not at the AUTO position, all of the select modes are in the manual mode (SELECT = MAN).
U).

If the result of the determination in step S8 is false, it is determined in step S12 whether the switching position Psw is the AUTO position. If the judgment result is true,
In step S13, the select mode is stored as an auto mode (SELECT = AUTO). In addition,
In the present system, when the select mode is set to the auto mode at the time when the ignition is turned on, the drive mode is designed to be set to the full time 4WD mode first. Means that the drive mode command is stored as the 4WD initial state, that is, the full-time 4WD mode (MODE = 4H).

If the result of the determination in step S12 is false, it is determined in step S14 whether or not the switching position Psw is the 4H position. If the judgment result is true,
In step S15, the drive mode command is stored as a full-time 4WD mode (MODE = 4H), and the select mode is stored as a manual mode (SELECT = MANU) as in step S10.

If the decision result in the step S14 is false, it is decided in a step S16 whether or not the switching position Psw is the 4HLc position. If the determination result is true, in step S18, the drive mode command is stored as the high direct connection 4WD mode (MODE = 4HLc),
The select mode is stored as the manual mode (SELECT = MANU) as in step S10.

If the decision result in the step S16 is negative, it is decided in a step S20 whether or not the switching position Psw is the 4LLc position. If the determination result is true, in step S22, the drive mode command is stored as the low direct connection 4WD mode (MODE = 4LLc),
Select mode is also changed to manual mode (SELEC
T = MANU).

In step S24 of FIG. 5, the select mode stored as described above is changed to the auto mode (SEL mode).
It is determined whether or not (ECT = AUTO). When step S13 is executed after step S12, the determination result of step S24 is true (Yes), and the select mode is the auto mode. In this case, the process proceeds to step S26.

When the switching position Psw of the drive mode changeover switch 115 is in the AUTO position and the select mode is the auto mode, the drive mode command is issued in addition to the full time 4WD mode (MODE = 4H) and the 2WD mode (MODE).
= 2H), High direct connection 4WD mode (MODE = 4HL)
It is possible to switch automatically to c). Therefore, in step S26, it is first determined whether or not the current drive mode command in the auto mode is the 2WD mode. If the determination result is true (Yes), the process proceeds to step S28.

If the drive mode command is the 2WD mode, it is determined in step S28 whether or not the 2WD release condition is satisfied, that is, whether or not the condition for exiting the 2WD mode and switching to the 4WD mode is satisfied. Do. Here, actually, the subroutine (drive switching instruction means) of the 2WD cancellation condition shown in FIGS. 7 and 8 is executed. 2WD
The parameters of the release condition include a vehicle speed (vehicle speed) V, an absolute value | Δ of a rotation speed difference between the rear propeller shaft and the front propeller shaft 16 (hereinafter referred to as a “peller rotation difference”).
Vc |, running load resistance fv, degree of bad road akuro, and degree of sporty sport. Based on these parameters, 2
It is determined whether the WD cancellation condition is satisfied.

When the vehicle is traveling in the 2WD mode, the front propeller shaft 16 is not rotating. Therefore, the rotation speed of the virtual front propeller shaft 16 is detected from the rotation speed of the right front wheel FW, and the virtual rotation speed and the rear propeller are detected. The absolute value | ΔVc | of the difference in rotation of the propeller is calculated based on the difference in rotation speed between the shaft and the shaft. Further, when traveling in the 4WD mode, the absolute value | ΔVc | of the rotation difference between the propellers is calculated based on the actual rotation speed difference between the front propeller shaft 16 and the rear propeller shaft.

In step S50 of FIG. 7, it is first determined again whether the drive mode command is the 2WD mode (MODE = 2H). If the determination result is true (Yes) and the drive mode command is the 2WD mode, then step S
Go to 52. In step S52, it is determined whether or not the vehicle speed (vehicle speed) V is higher than a predetermined value V1 (for example, 100 km / h). The vehicle speed (vehicle speed) V is estimated and calculated on the basis of the longitudinal acceleration Gx of the vehicle body detected by the longitudinal G sensor 96 (vehicle speed detecting means). I do. The predetermined value V1 (for example, 100 km / h) is set in consideration of high-speed running stability.

The determination result of step S52 is true (Yes).
If the vehicle speed V exceeds the predetermined value V1 (for example, 100 km / h), the process proceeds to step S54, where it is determined that the vehicle speed V has exceeded the predetermined value V1 by using a flag F2H4 as a control variable.
Set the value 1 to H and store it. If the determination result of step S52 is false (No), in step S56,
Rotation speed sensor (front and rear wheel rotation speed difference detecting means) 10
2 and the rotational speed sensor (front and rear wheel rotational speed difference detecting means) 104, 106
The absolute value | ΔVc | of the difference in rotation of the propeller detected based on the rotation speed information of the front propeller shaft 16
It is determined whether it is greater than Vc1 (for example, 30 rpm). Δ
Vc1 (for example, 30 rpm) is changed from 2WD mode to 4WD.
It is set to a value that seems to be a road surface condition or a running condition that requires switching to the mode, and is set to a level that does not easily switch to the 4WD mode due to road surface disturbance or tire pressure irregularity etc. Have been. If the determination result is true (Yes) and the absolute value | ΔVc | is ΔVc1 (for example, 30r
pm), the process proceeds to step S58, in which the fact that the absolute value | ΔVc | exceeds ΔVc1 is set to the flag F2H4H and stored.

If the decision result in the step S56 is false (No), in a step S60, the running load resistance fv
Is larger than a predetermined value fv1 (for example, 300 kgf). Here, the running load resistance fv is given by the following equation.
It is calculated based on (1). fv = fe-rl-ra-rr (1) where fe represents engine driving force, rl represents air resistance, ra represents acceleration resistance (considering gradient resistance), and rr represents rolling resistance (considering cornering drag). The details of each calculation are omitted here.

The predetermined value fv1 (for example, 300 kgf)
Is 4WD from 2WD mode such as sandy road driving and towing driving
The setting is made in consideration of a road surface state and a running state that require switching to the mode. By the way, actually, the fv
Is finally output after being subjected to filter processing (low-pass filter processing), but a detailed description thereof will be omitted here.

The determination result of step S60 is true (Yes).
And the running load resistance fv becomes a predetermined value fv1 (for example, 300 kgf).
If so, the process proceeds to step S62, in which the flag F2H4H is set to a value of 3 and stored that the running load resistance fv exceeds the predetermined value fv1. If the result of the determination in step S60 is false (No), in step S64, it is determined whether or not the degree of bad road akuro is greater than a predetermined value akuro1. The bad road degree akuro is calculated based on the magnitude of the longitudinal acceleration Gx. For example, the bad road degree akuro is determined to be larger as the magnitude and the change amount of the vibration component of the longitudinal acceleration Gx are larger. Here, the details are omitted. The predetermined value akuro1 is set to such a degree that it can be quickly switched from the 2WD mode to the 4WD mode when driving on a dirt road, but is not easily switched to the 4WD mode in a reflection block or the like on the center line. I have.

The determination result of step S64 is true (Yes).
If the degree of bad road akuro exceeds the predetermined value akuro1, the process proceeds to step S66, where the value 4 is set to the flag F2H4H and stored that the degree of bad road akuro exceeds the predetermined value akuro1. The determination result of step S64 is false (No)
In step S68, the sporty degree
It is determined whether sport is larger than a predetermined value sport1. This sporty degree sport is calculated based on the following equation (2).

Sport = (K6 · Gy + K7 · dθH / dt + K8 · θTH + K9 · dθTH / dt) / 4 (2) where K6, K7, K8 and K9 are predetermined coefficients, and Gy is the vehicle speed V and The calculated lateral acceleration calculated based on the steering wheel angle θH, etc., dθH / dt is the steering wheel angular velocity calculated based on the steering wheel angle θH, θTH is the throttle opening, dθ
TH / dt is the throttle opening speed.

That is, the sporty degree sport is larger as the calculated lateral acceleration Gy, the steering wheel angular velocity dθH / dt, the throttle opening θTH, and the throttle opening speed dθTH / dt are larger, that is, as the driver likes crisp driving. Parameters to be used. The specified value sport1
Is set so that the mode is quickly switched from the 2WD mode to the 4WD mode at least at the time of a fast lane change or hard running on a winding road or the like.

The determination result of step S68 is true (Yes).
If the sporty degree sport exceeds the predetermined value sport1, the process proceeds to step S70, and the sporty degree sp
The fact that ort exceeds the predetermined value sport1 is stored by setting a value 5 to the flag F2H4H. If the determination result in step S68 is false (No), it can be considered that the 2WD cancellation condition is not satisfied. In this case, in step S72, a value 0 is set to the flag F2H4H and stored.

In step S74, it is determined that the flag F2H4H set as described above is not 0. The determination result is true (Yes), that is, any one of the vehicle speed V, the absolute value | ΔVc | of the rotation difference of the propeller, the running load resistance fv, the degree of bad road akuro, and the degree of sporty sport exceeds the predetermined threshold. If this is the case and the flag F2H4H is not equal to 0, the process proceeds to step S76.

In step S76, the flag F2H4H is set to the value 2
Is determined. If the determination result is true (Yes), the process proceeds to step S78. In step S78, the timer TM2 (2off) for measuring time after the flag F2H4H is set to the value 2 is set to a predetermined time T10 (for example, 50 msec).
Is determined to be less than or equal to). If the determination result is true (Yes) and the value of the flag F2H4H is set to 2 and the timer TM2 (2off) has not yet reached the predetermined time T10, the timer TM2 (2off) is counted up in step S80.

If the result of the determination in step S76 is false (N
If the flag F2H4H is not the value 2 in o), in the next step S82, it is determined whether or not the flag F2H4H is the value 5 this time. If the determination result is true (Yes),
Next, the process proceeds to step S84. In step S84, a timer T for measuring time after the flag F2H4H is set to the value 5 is set.
It is determined whether or not M5 (2off) is equal to or shorter than a predetermined time T11 (for example, a value corresponding to 500 msec). If the determination result is true (Y
If the value of the flag F2H4H is set to 5 in es) and the timer TM5 (2off) has not yet reached the predetermined time T11,
In step S86, the timer TM5 (2off) is counted up.

If the result of the determination in step S82 is false (N
In o), if the flag F2H4H is neither the value 0 nor the value 2 or the value 5, that is, if the flag F2H4H is any of the values 1, 3 and 4, the flag F2H4H is determined in the next step S88.
It is determined whether or not a timer TM (2off) that measures time after 2H4H is set to these values is equal to or shorter than a predetermined time T12 (for example, a value corresponding to 1 second). If the determination result is true (Ye
If the timer TM (2off) has not reached the predetermined time T12 after setting any one of the value 1, the value 3, and the value 4 to the flag F2H4H in step s), in step S90, the timer T
M (2off) is counted up.

If the determination result in the above steps S78, S84 and S88 is false (No), the timer TM
When 2 (2off) reaches the predetermined time T10, the timer TM5 (2of
f) has reached the predetermined time T11 or the timer TM (2of
When f) reaches the predetermined time T12, the 2WD cancellation condition,
That is, it can be considered that the condition for switching from the 2WD mode to the 4WD mode has been completely satisfied without disturbance or the like. Time 4WD mode (MODE = 4H) is set (drive wheel switching signal).

On the other hand, if the decision result in the step S74 is false (N
If the flag F2H4H has the value 0 in o), it can be determined that the 2WD cancellation condition is not satisfied. In this case, the process proceeds to step S94, and the flag F is set as described above.
Timer TM2 (2of4h) used when 2H4H is not 0
f) Reset the timer TM5 (2off) and the timer TM (2off).

If the determination result of step S26 in FIG. 5 is false (N
o), the drive mode command is set to 2WD mode (MODE = 2
If not, in step S30, it is determined whether or not the current mode is the full-time 4WD mode (MODE = 4H). If the determination result is true (Yes), the process proceeds to step S31. Drive mode command is full time 4
In the case of the WD mode, in step S31,
The actual drive mode (actual drive mode) based on information from the T / F position switch 114 is the 2WD mode (actual MO mode).
DE = 2H) or full-time 4WD mode (actual MOD)
E = 4H) is determined. If the determination result is true (Yes), the process proceeds to step S32.

The drive mode command is a full time 4WD mode (MODE = 4H) and the actual drive mode is 2WD.
In the case of the mode (actual MODE = 2H) or the full-time 4WD mode (actual MODE = 4H), the condition for switching to the 2WD mode is satisfied in step S32, and the condition for switching from the 4WD mode to the 2WD mode is satisfied. Is determined. Here, FIG. 9 and FIG.
A 2WD entry condition subroutine (drive switching instruction means) shown in FIG.

The parameters for the 2WD entry condition include the vehicle speed V, the absolute value | ΔVc |
In addition to uro and sporty degree sport, there is the above-mentioned slope slope, and it is determined based on these parameters whether the 2WD entry condition is satisfied. In step S100 of FIG. 9, first, the drive mode command is set to the full time 4WD mode (M
ODE = 4H) is determined again. The determination result is true (Yes) and the drive mode command is full-time 4WD
If it is the mode, the process proceeds to step S102.

In step S102, the vehicle speed V is set to a predetermined value V
2 (for example, 80 km / h) or more is determined.
If the determination result is true (Yes) and the vehicle speed V is equal to or higher than the predetermined value V2 (for example, 80 km / h), then step S1 is performed.
Proceeding to 04, the timer TM1 (2on) is counted up so as to perform time counting after the vehicle speed V becomes equal to or higher than the predetermined value V2.
Then, in step S106, the timer TM1 (2on)
Is longer than a predetermined time T21 (for example, a value corresponding to 1 second), and if the determination result is true (Yes), the timer TM
When it is determined that 1 (2on) has exceeded the predetermined time T21,
In the next step S108, a value 1 is set to a flag F4H2H, which is a control variable, to store that the vehicle speed V is equal to or higher than a predetermined value V2.

The determination result of step S102 is false (No)
In step S110, it is determined whether or not the slope slope is equal to or greater than a predetermined value slope1 (for example, 5 deg). If the determination result of step S110 is true (Ye
If the gradient slope is equal to or greater than the predetermined value slope1 (for example, 5 deg) in s), the process proceeds to step S112, and the gradient sl
The timer TM2 (2on) is counted up in order to measure the time after ope has reached the predetermined value slope1.

In step S114, the timer TM2 (2on) is set to a predetermined time T22 (a value corresponding to 500 msec).
If the determination result is true (Yes) and it is determined that the timer TM2 (2on) has exceeded the predetermined time T22, in the next step S116, the gradient slope is set to the predetermined value slope1 (for example, 5 deg.) Or more is stored by setting a value 2 to the flag F4H2H.

If the result of determination in step S110 is false (No)
In step S118, it is determined whether or not the absolute value | ΔVc | of the differential rotation of the propeller is equal to or larger than ΔVc2 (for example, 15 rpm). When the determination result is true (Yes) and the absolute value | ΔVc | is equal to or greater than ΔVc2 (for example, 15 rpm), the process proceeds to step S120, and after the absolute value | ΔVc | The timer TM3 (2on) is counted up to perform the time measurement.

Then, in a step S122, it is determined whether or not the timer TM3 (2on) has exceeded a predetermined time T23 (for example, a value corresponding to 100 msec), and the determination result is true (Ye
If it is determined in step s) that the timer TM3 (2on) has exceeded the predetermined time T23, in the next step S124, a value 3 is set to the flag F4H2H to indicate that the absolute value | ΔVc | Set and memorize.

The determination result of step S118 is false (No)
In step S126, it is determined whether or not the traveling load resistance fv is equal to or greater than a predetermined value fv2 (for example, 250 kgf). If the determination result is true (Yes) and the traveling load resistance fv is equal to or greater than the predetermined value fv2 (for example, 250 kgf), the process proceeds to step S128, where the traveling load resistance fv is determined.
The timer TM4 (2on) is counted up in order to perform time measurement after the value becomes equal to or more than the predetermined value fv2.

Then, in step S130, it is determined whether or not the timer TM4 (2on) has exceeded a predetermined time T24 (for example, a value corresponding to 2 seconds), and the determination result is true (Yes).
If it is determined that the timer TM4 (2on) has exceeded the predetermined time T24 in step S132, the value 4 is set in the flag F4H2H and stored in the next step S132 to indicate that the running load resistance fv is equal to or greater than the predetermined value fv2. .

The determination result of step S126 is false (No)
In step S134, in the case of
It is determined whether or not o is equal to or more than a predetermined value akuro2 (akuro2 <akuro1). The judgment result is true (Yes) and the degree of bad road akuro
Is greater than or equal to the predetermined value akuro2, then step S1
Proceeding to 36, the timer TM5 (2on) is counted up so as to perform time counting after the degree of bad road akuro becomes a predetermined value akuro2 or more.

Then, in a step S138, it is determined whether or not the timer TM5 (2on) has exceeded a predetermined time T25 (for example, a value corresponding to 1 second), and the determination result is true (Yes).
If it is determined that the timer TM5 (2on) has exceeded the predetermined time T25 in step S140, in the next step S140, the degree of bad road
The flag F4H2H is set to a value of 5 to store that akuro is greater than or equal to the predetermined value akuro2.

The determination result of step S134 is false (No)
In step S142, it is determined whether or not the sporty degree sport is equal to or greater than a predetermined value sport2 (sport2 <sport1). When the determination result is true (Yes) and the sporty degree sport is equal to or more than the predetermined value sport2, the process proceeds to step S144, and the timer TM is used to measure time after the sporty degree sport becomes equal to or more than the predetermined value sport2.
Count up 6 (2on).

Then, in a step S146, it is determined whether or not the timer TM6 (2on) has exceeded a predetermined time T26 (for example, a value corresponding to 100 msec), and if the determination result is true (Ye
If it is determined in s) that the timer TM6 (2on) has exceeded the predetermined time T26, in the next step S148, the value 6 is set in the flag F4H2H to store that the sporty degree sport is equal to or more than the predetermined value sport2. I do.

The determination result of step S142 is false (No)
In step S150, the flag F4H2H
Is set to the value 0 and stored. By the way, step S106
Is false (No), step S1
14 is executed, and the determination result of step S114 is false (N
In the case of (o), step S122 is executed, and steps S130 and S138 are similarly executed. If the determination result of step S146 is false (No), step S1 is executed.
In step S150, a value 0 is set to the flag F4H2H and stored in the same manner as in the case where the determination result at step 42 is false (No).

The threshold value of each parameter used in the 2WD entry condition is set so as not to cause the condition determination and the hunting under the 2WD cancellation condition.
In step S152, it is determined whether or not the value of the flag F4H2H set as described above is 0. The determination result is true (Yes), that is, the above-described steps S102 and S1
10, all determination results of step S118, step S126, step S134, and step S142 are false (N
In the case of o), when the flag F4H2H has a value of 0, that is, any one of the vehicle speed V, the slope slope, the absolute value | ΔVc | If the threshold value does not exceed the threshold value, or if the time after all of these parameters have exceeded the threshold value does not exceed the predetermined time, the process proceeds to step S1.
Proceed to 54.

In step S154, it is determined whether the vehicle speed V is higher than a predetermined vehicle speed V3 (for example, 5 km / h). If the determination result is false (No) and the vehicle speed V is the predetermined vehicle speed V3 (for example, 5 k
m / h) or less, the drive mode is more than
In order to prevent switching from the WD mode to the 2WD mode, the process exits from the routine without doing anything. On the other hand, step S
If the determination result of 154 is true (Yes), the vehicle speed V is equal to the predetermined vehicle speed V
If it is larger than 3 (for example, 5 km / h), the process proceeds to step S156.

In step S156, it is determined whether or not the timer TM (2on) for starting time measurement at the same time when the value of the flag F4H2H is set to 0 has exceeded a predetermined time T27 (for example, 3 minutes). If the determination result is false (No) and the timer TM (2on) has not yet reached the predetermined time T27 (for example, 3 minutes), the timer TM (2on) is counted up in the next step S158.

On the other hand, this routine is repeatedly executed,
If the decision result in the step S156 is true (Yes), the timer T
When it is determined that M (2on) has exceeded the predetermined time T27, the flag F4H2H has a value of 0, and it is considered that the 2WD inrush condition, that is, the condition for exiting the 4WD mode and switching to the 2WD mode is completely satisfied. In this case, the process proceeds to step S160, and the drive mode command is set to the 2WD mode (MODE = 2H).

On the other hand, if the result of the determination in step S152 is false (No) and the value of the flag F4H2H is not 0, that is, the above-described steps S102, S110, and S11
8, step S126, step S134, step S
142 is true (Yes), that is, any one of the vehicle speed V, the slope slope, the absolute value | ΔVc | of the difference in the rotation of the propeller, the running load resistance fv, the degree of bad road akuro, and the degree of sporty sport If at least one of the states exceeds a predetermined threshold for a predetermined time, 2
It can be determined that the WD entry condition is not satisfied,
In this case, the process proceeds to step S162, and the timer TM used when the value of the flag F4H2H is not 0 as described above.
1 (2on) to reset the timer TM6 (2on) and the timer TM (2on).

If the determination result of step S31 in FIG. 5 is false (N
In the case of o), or after the subroutine of the 2WD entry condition is executed in step S32, step S
At 33, whether the actual drive mode (actual drive mode) based on the information from the T / F position switch 114 is the full time 4WD mode (actual MODE = 4H) or the high direct connection 4WD mode (actual MODE = 4HLc) Is determined. If the determination result is true (Yes),
Next, the process proceeds to step S34.

When the drive mode command is the full time 4WD mode (MODE = 4H) and the actual drive mode is the full time 4WD mode (actual MODE = 4H) or the high direct connection 4WD mode (actual MODE = 4HLc) In step S34, the direct connection 4WD entry condition is satisfied, and the high direct connection 4
It is determined whether a condition for switching to the WD mode is satisfied. Here, actually, a subroutine (drive switching command means) of the direct connection 4WD rush condition shown in FIG. 11 is executed.

The parameters of the direct connection 4WD entry condition include the above-described vehicle speed V, the absolute value | ΔVc |
In addition to the running load resistance fv, the difference between the larger one of the rotational speeds of the rear propeller shaft and the front propeller shaft 16 (select high value) and the converted value when the vehicle speed V is converted to the rotational speed of the propeller shaft, that is, select There is a high rotation speed difference ΔVt, and it is determined based on these parameters whether the direct connection 4WD entry condition is satisfied.

In step S170 of FIG. 11, first, the drive mode command is set to the full time 4WD mode (MODE = 4
H) and whether the actual drive mode is also the full-time 4WD mode (actual MODE = 4H). If the determination result is true (Yes), the process proceeds to step S172. In step S172, it is determined whether or not the vehicle speed V is equal to or lower than a predetermined value V4 (for example, 20 km / h). When the determination result is false (No) and the vehicle speed V is equal to the predetermined value V4
If it is greater than (for example, 20 km / h), the routine exits without doing anything. On the other hand, if the determination result is true (Yes) and the vehicle speed V is equal to or less than the predetermined value V4 (for example, 20 km / h), the process proceeds to step S174.

In step S174, it is determined whether or not the absolute value | ΔVc | of the rotation difference of the propeller is larger than ΔVc3 (for example, 500 rpm). If the determination result is true (Yes) and the absolute value | ΔVc | exceeds ΔVc3 (for example, 500 rpm), the process proceeds to step S176, where the absolute value | ΔVc | The flag F4H4
Set the value 1 to L and store it.

If the determination result of step S174 is false (No)
In the case of, in step S178, it is determined whether or not the traveling load resistance fv is larger than a predetermined value fv3 (for example, 400 kgf). If the determination result is true (Yes) and the traveling load resistance fv is equal to or greater than a predetermined value fv3 (for example, 400 kgf), the process proceeds to step S180, and the traveling load resistance f
The fact that v is greater than or equal to the predetermined value fv3 is stored by setting the value 2 to the flag F4H4L.

If the result of the determination in step S178 is false (No)
In step S182, in step S182, the vehicle speed V is equal to or less than the predetermined value V5 (eg, 5 km / h) and the select high rotation speed difference ΔVt is equal to the predetermined value ΔVt1 (eg, 100r
pm) is determined. If the determination result is true (Y
es), when the vehicle speed V is equal to or less than a predetermined value V5 (for example, 5 km / h) and the select high rotation speed difference ΔVt is larger than a predetermined value ΔVt1 (for example, 100 rpm),
Then, the process proceeds to a step S184, in which a value 3 is set to the flag F4H4L and stored. This determination means determination of whether or not the vehicle is in a stack (one-wheel stack, diagonal stack) state.

If the result of the determination in step S182 is false (No)
If it is, the process proceeds to step S186, where a value 0 is set in the flag F4H4L and stored. When the flag F4H4L is set as described above, it is determined in step S188 that the value of the flag F4H4L is not 0. If the determination result is true (Yes) and the flag F4H4L is a value 1 to a value 3 and not a value 0, the process proceeds to step S190.

In step S190, it is determined whether or not a timer TM (ron) for measuring time after setting the flag F4H4L is equal to or less than a predetermined time T30 (for example, a value corresponding to 1 second). If the determination result is true (Yes), the timer T
If M (ron) is equal to or shorter than the predetermined time T30, the timer TM (ron) is counted up in step S192.

On the other hand, if the determination result of step S190 is false (No) and it is determined that the timer TM (ron) has reached the predetermined time T30, it can be considered that the direct connection 4WD entry condition has been satisfied. If so, then step S19
6, the drive mode command is set to the high direct connection 4WD mode (M
ODE = 4HLc) (direct connection switching signal). That is, in this case, when the vehicle is traveling at a low speed and is traveling on a steep slope or a sandy road, the full-time 4WD mode is switched to the high direct connection 4WD mode. Even in the (single wheel stack, diagonal stack) state, the mode is switched from the full time 4WD mode to the high direct connection 4WD mode.

On the other hand, if the result of the determination at step S188 is false (No) and the value of the flag F4H4L is 0, that is, the above-described steps S174, S178, and S182
If all the determination results are false (No), the direct connection 4
It can be determined that the WD entry condition is not satisfied,
In this case, the process proceeds to step S194, and the timer TM (ron) used when the value of the flag F4H4L is not set to 0 as described above is reset.

If the determination result of step S30 in FIG. 5 is false (N
In the case of o), in step S38, the current drive mode command is set to the high direct connection 4WD mode (MODE = 4HL).
c) is determined. If the determination result is true (Y
In the case of es), the process proceeds to step S40. If the drive mode command is the high direct connection 4WD mode, in step S40, it is determined whether the direct connection 4WD release condition is satisfied and the condition for exiting the high direct connection 4WD mode and switching to the full time 4WD mode is satisfied. Do. Here, in practice, a subroutine (drive switching command means) of the direct connection 4WD release condition shown in FIG. 12 is executed.

The parameters of the direct connection 4WD cancellation condition include the above-mentioned vehicle speed V, running load resistance fv, gradient slope, abrupt road degree akuro, throttle opening θTH and on / off information from the brake switch 112, and these parameters. It is determined whether or not the direct connection 4WD release condition is satisfied based on In step S200 of FIG. 12, first, the drive mode command is set to the high direct connection 4WD mode (MODE = 4HL).
It is determined again whether or not c). If the determination result is true (Y
If es), the process proceeds to step S202.

In step S202, the vehicle speed V is set to a predetermined value V
6 (for example, 30 km / h) or more is determined.
If the determination result is true (Yes) and the vehicle speed V is equal to or higher than the predetermined value V6 (for example, 30 km / h), then step S2 is performed.
Go to 04. In step S204, the running load resistance fv
Is smaller than a predetermined value fv4 (for example, 300 kgf). When the determination result is true (Yes) and the traveling load resistance fv is smaller than the predetermined value fv4 (for example, 300 kgf), the process proceeds to step S206.

In step S206, it is determined whether or not the gradient slope is smaller than a predetermined value slope2 (for example, 15 degrees). The judgment result is true (Yes) and the slope slope is the predetermined value s
If it is smaller than lope2 (for example, 15 deg), the process proceeds to step S208. In step S208, it is determined whether or not the throttle opening θTH is larger than a predetermined value θTH1 (for example, 5%) based on information from the throttle opening sensor 98. When the determination result is true (Yes) and the throttle opening θTH is larger than the predetermined value θTH1 (for example, 5%), the process proceeds to step S210.

In step S210, the brake pedal has not been depressed, and an off signal has been output from the brake switch 112, that is, the brake signal
It is determined whether or not it is FF. The judgment result is true (Yes)
If the brake signal brk is OFF, the process proceeds to step S212. In step S212, it is determined whether or not the degree of bad road akuro is smaller than a predetermined value akuro3. The determination result is true (Yes), and the degree of bad road akuro is a predetermined value a.
If it is smaller than kuro3 (= akuro2), the process proceeds to step S214.

In step S214, step S2
02 through step S212 are true (Ye
It is determined whether or not the timer TM (roff) for measuring the time after s) is equal to or less than a predetermined time T40 (for example, a value corresponding to 5 seconds). If the determination result is true (Yes), the timer TM (r
off) is equal to or shorter than the predetermined time T40, step S2
At 16, the timer TM (roff) is counted up.

On the other hand, if the result of the determination in step S214 is false (No) and it is determined that the timer TM (roff) has reached the predetermined time T40, it can be considered that the direct connection 4WD release condition has been satisfied. If so, then step S21
Proceeding to 8, the drive mode command is set to the full time 4WD mode (MODE = 4H). In other words, here, when the vehicle is not traveling on steep slopes, sandy roads, etc.,
The mode is switched from the high direct connection 4WD mode to the full time 4WD mode.

On the other hand, if any one of the above-described steps S202 to S212 is false (No), it can be determined that the direct connection 4WD release condition is not satisfied. Exit this routine without doing anything. By the way, when the 2WD cancellation condition routine of step S28 is executed, the timer TM used in the 2WD cancellation condition routine in step S29 is used.
Timers other than (2off) etc., 2WD rush conditions, direct connection 4W
The timer used for other condition determination such as the D rush condition and the direct connection 4WD release condition is reset. This provides for a case where another condition determination such as a next 2WD entry condition, a direct connection 4WD entry condition, a direct connection 4WD release condition, or the like is performed.
Similarly, when the determination result of step S33 is false (No), or when the routine of the direct connection 4WD entry condition of step S34 is executed, 2W is set in step S35.
Reset the timers other than the timer TM (2on) and timer TM (ron) used in the routine of the D entry condition and the direct connection 4WD entry condition, that is, the timer used for the condition determination such as the 2WD release condition and the direct connection 4WD release condition. Keep it. further,
When the routine of the direct connection 4WD release condition of step S40 is executed, the timer other than the timer TM (roff) used in the routine of the direct connection 4WD release condition in step S41, that is, the 2WD release condition, the 2WD inrush condition, the direct connection 4W
The timer used for determining other conditions such as the D entry condition is reset.

Also, the determination result of step S24 in FIG. 5 is false (No), and the select mode is the auto mode (SEL
Manual mode (SEL) instead of ECT = AUTO
If (ECT = MANU), in step S25, all the timers used in the above-described auto mode condition determination are reset. Thereby, the determination result of step S24 is set to true (Yes) next time, and a case is prepared in which the condition determination in the auto mode is performed.

When the drive mode command is determined as described above, it is next determined in step S42 whether or not the vehicle speed V is lower than a predetermined vehicle speed V0 (for example, 2 km / h). That is, here, it is determined whether or not the vehicle is substantially stopped. The determination result of step S42 is false (No)
If the vehicle speed V is equal to or higher than the predetermined vehicle speed V0 (for example, 2 km / h) and the vehicle is in a running state, the process proceeds to step S4.
Proceed to 4.

In step S44, # 1 motor control is performed. This # 1 motor control means the control of the motor unit 202 of the shift actuator 60, that is, the electric motor 204 when the vehicle is running. Actually, in the # 1 motor control, the flowchart of the # 1 motor control routine shown in FIGS. 13 to 15 is executed, and will be described below with reference to FIGS.

In step S250 in FIG. 13, it is determined whether the drive mode command is the 2WD mode (MODE = 2H) and the actual drive mode is also the 2WD mode (actual MODE = 2H). If the determination result of step S250 is false (No), the process proceeds to step S254, where the drive mode command is the 2WD mode (MODE = 2H) and the actual drive mode is the 2WD mode and the full time 4WD.
It is determined whether the current mode is an intermediate mode (actual MODE = 2H-4H) or a full-time 4WD mode (actual MODE = 4H). The case where the actual drive mode is intermediate between the 2WD mode and the full-time 4WD mode means that the shift actuator 60 is in the middle of operation between the 2WD position and the full-time 4WD position. If the determination result is true (Yes), then step S25 is performed.
Proceed to 6.

In step S256, a 2WD rush process is performed based on the drive mode command. In this 2WD entry process, a flowchart of a 2WD entry process routine shown in FIG. 16 is executed. In step S400 of FIG. 16, first, the absolute value | ΔVc |
20 rpm). If the determination result is false (N
If in o) the absolute value | ΔVc |
Go to 02.

In step S402, it is determined whether the driving force (input torque) Ftf from the engine 2 to the transfer device 6 is larger than a predetermined value Ftf10. Note that this driving force F
tf is calculated from the engine output information,
The value is substantially equal to the above-described engine driving force fe (input torque calculating means). The predetermined value Ftf10 is a variable value set according to the vehicle speed (vehicle speed) V, as shown in FIG. The value X7 of the vehicle speed V in FIG. 31 is, for example, 2 km / h, and the value X8 is, for example, 50 km / h. If the determination result is false (N
If the driving force Ftf is equal to or less than the predetermined value Ftf10 in o),
Next, the process proceeds to step S404.

In step S404, it is determined whether or not the steering wheel angle θH is larger than a predetermined value θH10 (for example, 180 degrees) and the vehicle speed V is smaller than a predetermined value V10 (for example, 25 km / h). If the determination result is false (No) and the steering wheel angle θH is equal to or less than the predetermined value θH10 (for example, 180 deg) and the vehicle speed V is equal to or more than the predetermined value V10 (for example, 25 km / h), the process proceeds to step S406. Perform reverse motion processing.

In other words, the absolute value | ΔVc |
Is less than or equal to a predetermined value Ftf10, and when the steering wheel angle θH is less than or equal to a predetermined value θH10 (for example, 180 deg) and the vehicle speed V is greater than or equal to a predetermined value V10 (for example, 25 km / h), Can move the coupling sleeve 82 smoothly, and it can be determined that the shift actuator 60 may be operated according to the drive mode command (MODE = 2H).
At 06, the electric motor 204 is operated (connection switching means). However, here, the electric motor 204 defines the counterclockwise direction as viewed in FIG.
Clockwise is defined as the reverse direction, that is, the reverse state.
Therefore, here, as is clear from FIG. 1, the operation of the electric motor 204 for setting the actual drive mode to the 2WD mode is in the reverse rotation direction, which is a motor reverse operation process.

In the motor reversing process, the flowchart of the motor reversing process routine shown in FIG. 22 is executed. FIG.
In step S500, it is determined whether the motor protection operation timer TM1ccw is equal to or shorter than a predetermined time T50 (for example, a value corresponding to 10 seconds). The determination result is true (Yes) immediately after the start of the motor reverse rotation process. In this case, the operation timer TM1ccw is counted up in step S502, and a motor reverse rotation command is output to the electric motor 204 in step S504. Then, the electric motor 204 is reversed.

On the other hand, if the determination result of step S500 is false (No) and the operation timer TM1ccw has reached the predetermined time T50 (for example, a value corresponding to 10 seconds), the process proceeds to step S506, and this time the operation timer The stop timer TM2ccw provided separately from TM1ccw is counted up, and the electric motor 204
To output a motor stop command to stop the electric motor 204.

In step S510, it is determined whether or not the stop timer TM2ccw has exceeded a predetermined time T52 (for example, a value corresponding to 1 second), and if the determination result is false (N
In the case of o), after step S500, step S5
At 06, the stop timer TM2ccw continues counting up. On the other hand, if the determination result is true (Yes), both the operation timer TM1ccw and the stop timer TM2ccw are reset in step S512.

That is, in this motor reverse operation step, the electric motor 204 is kept for a predetermined time T50 (for example, 10 seconds).
(the value according to c) can be reversed to the limit, and when the electric motor 204 is driven for a predetermined time T50, the motor is stopped for a predetermined time T52 (for example, a value corresponding to 1 second). By repeating the operation and the stop of the electric motor 204 in this manner, an overload is prevented when the gear change of the transfer device 6 is not smoothly completed, and the electric motor 204 is protected well.

When the electric motor 204 operates in the reverse direction and the shift actuator 60 operates, the shift fork 84 operates to connect the coupling sleeve 82 to the clutch gears 74 and 80. The actual drive mode shifts to the 2WD mode side. By the way, when the motor reverse operation is being performed in step S406, in step S407, the control amount ta of the clutch hydraulic pressure supplied to the hydraulic multiple disc clutch 88 is set to a predetermined value ta0 (slight hydraulic pressure).

As described above, when the clutch hydraulic pressure is supplied to the hydraulic multi-plate clutch 88, the clutch gears 74, 78, 8
As a result, the rotation of the clutch gear 74 and the clutch gear 74, 80 is facilitated by the coupling sleeve 82. Thereby, abnormal noise and the like generated when the coupling sleeve 82 moves are eliminated, and the shift to the 2WD mode from the actual driving mode can be realized more favorably.

Steps S400 and S4 in FIG.
02, the determination result in step S404 is true (Ye
In the case of s), it can be determined that the shift actuator 60 should not be operated, and the motor stop processing is executed in step S408, and the electric motor 204 is held in the stopped state. On the other hand, step S25 in FIG.
If the determination result of step 4 is false (No), then step S
258 is executed, and the drive mode command is set to the 2WD mode (M
ODE = 2H) and the actual drive mode is intermediate between the full-time 4WD mode and the high direct connection 4WD mode (actual MO mode).
DE = 4H-4HLc) or the high direct connection 4WD mode (actual MODE = 4HLc). In addition,
Actual drive mode is full time 4WD mode and high direct connection 4W
The case where the shift actuator 60 is in the middle of the D mode is the same as described above in that the shift actuator 60 is connected to the full time 4WD position and the high direct connection 4WD.
This means that the operation is being performed between the WD position and the WD position. If the determination result is true (Yes), the process proceeds to step S260.

In step S260, a direct connection 4WD release process is performed based on the drive mode command. In other words, here
Since there is a full-time 4WD position between the 2WD position and the high direct connection 4WD position of the transfer device 6, the high direct connection 4WD mode is temporarily released so that the actual drive mode is changed to the full time 4WD mode. Actually, this directly connected 4WD
In the release processing, the flowchart of the direct connection 4WD release processing routine shown in FIG. 17 is executed.

In step S420, it is determined whether or not the driving force Ftf is greater than a predetermined value Ftf20 (for example, 200 kgf). When the determination result is false (No), the driving force Ftf is equal to the predetermined value F.
If it is equal to or less than tf20, the process proceeds to step S422. In step S422, the steering wheel angle θH becomes the predetermined value θH.
It is determined whether the vehicle speed V is 20 (for example, 120 deg) and the vehicle speed V is lower than a predetermined value V20 (for example, 2 km / h). When the determination result is false (No), the steering wheel angle θH is a predetermined value θH
20 (for example, 120 deg) or less and the vehicle speed V is a predetermined value V20
If the speed is equal to or higher than, for example, 2 km / h, the process proceeds to step S424, and the motor reverse movement process is performed as described above.

That is, the driving force Ftf is less than a predetermined value Ftf20 (for example, 200 kgf), the steering wheel angle θH is less than a predetermined value θH20 (for example, 120 deg), and the vehicle speed V is a predetermined value V20 (for example, 2 km / h). In the case described above, the coupling sleeve 82 can be smoothly moved between the clutch gears 74 and 78, and it can be determined that the shift actuator 60 may be operated in response to the drive mode command. In step S424, the electric motor 204 is operated.

As described above, when the electric motor 204 operates in the reverse direction and the shift actuator 60 operates, the shift fork 84 disconnects the coupling between the coupling sleeve 82 and the clutch gear 80, and connects the clutch gears 74 and 78 to each other. In other words, the actual drive mode shifts to the full-time 4WD mode.

When the motor reverse movement process is performed in step S424, the control amount ta of the clutch hydraulic pressure supplied to the hydraulic multiple disc clutch 88 is set to the predetermined value in step S425, as in the case of the 2WD rush process. It is set to ta0 (micro oil pressure). As a result, the clutch gears 74, 78, and 80 also rotate substantially integrally and synchronously, so that the coupling sleeve 82 and the clutch gear 80 can be easily disconnected, and the high direct connection 4 can be achieved.
Switching shock at the time of transition from the WD mode to the full-time 4WD mode can be suppressed. Therefore, abnormal noise and the like generated when the coupling sleeve 82 moves are also eliminated, and the full-time 4WD in the actual drive mode is more favorably achieved.
Transition to the mode will be realized.

Steps S420 and S4 in FIG.
If each of the determination results of step 22 is true (Yes), it can be determined that the shift actuator 60 should not be operated, and the motor stop processing is executed in step S426, and the electric motor 204 is also kept in the stopped state. . Further, when the shift of the actual drive mode to the full-time 4WD mode is realized by execution of step S260, the above-described 2WD rush process is performed in step S256 via steps S250 and S254, thereby executing the 2WD in the actual drive mode. The transition to the mode is realized.

On the other hand, if the decision result in the step S250 is true (Yes), that is, if the shift actuator 60
The operation of the electric motor 204 causes the shift fork 84
Moves to the input shaft 8 side, and as shown in FIG. 32, the coupling sleeve 82 is set to a position (2WD position) where only the clutch gears 74 and 80 are connected to each other, and the drive mode command matches the actual drive mode. If so, step S25
In FIG. 1, the freewheel hub mechanism 19 is moved to a separated state, that is, a free state (HAB = FR), as shown in FIG.
EE). Then, it is no longer necessary to operate the electric motor 204 that has been reversed in step S406 of the 2WD entry process and step S424 of the direct connection 4WD release process, and a motor stop process is performed in step S252.
The electric motor 204 is kept in a stopped state. This allows
The vehicle is in the 2WD state.

In step S270 of FIG. 14, it is determined whether the drive mode command is the full-time 4WD mode (MODE = 4H) and the actual drive mode is also the full-time 4WD mode (real MODE = 4H). Step S
If the determination result at 270 is false (No), the process proceeds to step S274, where the drive mode command is set to the full-time 4WD
Mode (MODE = 4H) and the actual drive mode is the 2WD mode (actual MODE = 2H) or, similarly to the above, the actual drive mode is intermediate between the 2WD mode and the full-time 4WD mode (actual MODE = 2H-4H). It is determined whether or not. If the determination result is true (Yes), the process proceeds to step S276.

In step S276, 2WD release processing is performed based on the drive mode command. In the 2WD release processing, a flowchart of a 2WD release processing routine shown in FIG. 18 is executed. In step S430 in FIG. 18, first, it is determined whether or not the freewheel hub mechanism 19 is in the separated state, that is, in the free state (HAB = FREE).
If the determination result is false (No), the freewheel hub mechanism 19 is not in the separated state (HAB = FREE) but in the locked state (H
If AB = LOCK), then step S43 is executed.
Proceed to 4.

In step S434, the control amount ta of the clutch hydraulic pressure supplied to the hydraulic multiple disc clutch 88 is set.
As shown in the map of FIG. 19, the control amount ta of the clutch oil pressure is set in advance in accordance with the absolute value | ΔVc | of the rotation difference of the propeller (clutch control means). The value X1 of the absolute value | ΔVc | in FIG. 19 is, for example, 5 rpm, and the value X2 is, for example, 200 rpm.

As described above, when the hydraulic pressure is supplied to the hydraulic multi-plate clutch 88, the clutch gears 74, 78, 80 rotate substantially integrally and synchronously by the engagement of the hydraulic multi-plate clutch 88 as described above. I will be. The front propeller shaft 16 is provided with a freewheel hub mechanism 19.
Therefore, the transfer device 6 is rotated substantially in accordance with the rotation of the front wheel FW due to the connection of the vehicle, that is, the substantially directly connected 4WD state, that is, the 4WD state by the clutch (on-demand 4WD state).
It is said.

In step S436, it is determined whether or not the absolute value | ΔVc | of the rotation difference of the propeller is greater than a predetermined value ΔVc30 (for example, 30 rpm) (connection determining means). If the result of the determination is false (No) and the absolute value | ΔVc | (front and rear wheel rotation speed difference) of the difference in the rotation of the propeller is equal to or smaller than the predetermined value ΔVc30 (for example, 30 rpm), the process proceeds to step S438. In step S438, it is determined whether the driving force (input torque) Ftf is greater than a predetermined value (specified value) Ftf30 (connection determining means). The predetermined value Ftf30 is the same value as the predetermined value Ftf10. That is, as shown in FIG. 31, the value is variably set according to the vehicle speed (vehicle speed) V. If the determination result is false (No) and the driving force Ftf is equal to or less than the predetermined value Ftf30, the process proceeds to step S440.

In step S440, the steering wheel angle θH is set to a predetermined value θH30 (for example, 180 de, similarly to the predetermined value θH10).
g) and the vehicle speed V is a predetermined value V30 (for example,
As in the case of the predetermined value V10, it is determined whether or not the speed is less than 25 km / h (low-speed turning state) (connection determining means, low-speed turning state detecting means). If the determination result is false (No), the steering wheel angle θ
H is equal to or less than a predetermined value θH30 (for example, 180 deg) and the vehicle speed V
Is greater than or equal to a predetermined value V30 (for example, 25 km / h), the process proceeds to step S442, and a motor operation process is performed.

That is, the absolute value | ΔVc | of the rotation difference of the propeller becomes equal to or less than ΔVc30 (eg, 30 rpm), the driving force Ftf is equal to or less than the predetermined value Ftf30, and the steering wheel angle θH is equal to or less than the predetermined value θH30 (eg, 180 deg). If the vehicle speed V is equal to or higher than the predetermined value V30 (for example, 25 km / h), it can be determined that the shift actuator 60 may be operated in response to the drive mode command (MODE = 4H). The electric motor 204 is operated (connection switching means). Here, the electric motor 204 operates counterclockwise as viewed in FIG. 1, that is, in the normal rotation direction.

In the motor operation processing, a flowchart of a motor operation processing routine shown in FIG. 23 is executed (steps S520 to S532). The motor operation processing routine includes an operation timer TM1ccw for motor protection and a stop timer T in the motor reverse operation processing routine.
M2ccw is set to the operation timer TM1cw and the stop timer TM2, respectively.
cw, and the motor reverse rotation command is merely a motor forward rotation command. The processing procedure is the same as that in the case of the motor reverse rotation processing routine, and a description thereof will be omitted here. That is,
In the step of the motor operation processing, the electric motor 204 is set to a predetermined time T60 (for example, a value corresponding to 10 seconds).
, And when the electric motor 204 is driven for a predetermined time T60, a predetermined time T62
(For example, a value corresponding to 1 second). As a result, similarly to the above, overload when the gear switching of the transfer device 6 is not completed smoothly is prevented, and the electric motor 204 is well protected.

Steps S436 and S4 in FIG.
38, the determination result of step S440 is true (Ye
In the case of s), it can be determined that the shift actuator 60 should not be operated, and the motor stop processing is executed in step S444, and the electric motor 204 is also kept stopped. On the other hand, step S430
Is true (Yes) and the freewheel hub mechanism 1
If 9 is in the separated state (HAB = FREE), the process advances to step S432 to perform HAB control.

In HAB control, the freewheel hub mechanism 1
9 is performed. In this HAB control, a flowchart of a HAB control routine shown in FIG. 24 is executed.
In step S600 of FIG. 24, the vehicle speed V is increased to a predetermined value V40.
(For example, 4 km / h) or less. If the determination result is false (No) and the vehicle speed V is a predetermined value V40 (for example, 4 km
If it is larger than (/ h), the process proceeds to step S602.

In step S602, it is determined whether or not the absolute value | ΔVc | of the rotation difference of the propeller is equal to or smaller than ΔVc40 (for example, 140 rpm). If the result of the determination is false (No) and the absolute value | ΔVc | of the rotation difference of the propeller is larger than ΔVc40, the process proceeds to step S604. In step S604, the rotational speed difference between the clutch gear 20 and the clutch gear 22, that is, the rotational speed difference ΔNF between the rotational speed NFL of the clutch gear 20 and the rotational speed NFR of the clutch gear 22 (ΔNF = N
FL-NFR) is determined to be less than or equal to a predetermined value ΔNF1 (for example, 60 rpm).

For example, when the vehicle is traveling at a high speed in the 2WD mode and the rotation speed of the front propeller shaft 16 is zero, the clutch gear 20 rotates through the front wheel differential 18 in the rotation direction (+ direction) of the front wheel FW. Are rotated at substantially the same rotational speed in the opposite direction (−direction). Therefore, in this case, the determination result of step S604 is false (No), and the rotation speed difference ΔNF is larger than the predetermined value ΔNF1 (for example, 60 rpm), and then the process proceeds to step S606.

In step S606, the control amount ta of the clutch hydraulic pressure supplied to the hydraulic multiple disc clutch 88 is set.
In this case, the control amount ta of the clutch oil pressure is set in advance according to the rotation speed difference ΔNF as shown in the map of FIG. The value X5 of the rotational speed difference ΔNF in FIG. 25 is, for example, 60 rpm, and the value X6 is, for example, 300 rpm.

As described above, when the hydraulic pressure is supplied to the hydraulic multiple disc clutch 88, the front propeller shaft 16 starts to rotate as described above, and the clutch gear 2
0 is rotated in the rotational direction (+ direction) of the front wheel FW, that is, in the same direction as the rotational direction of the clutch gear 22, and the rotational speed difference ΔNF is reduced. In step S616,
The rotational speed difference ΔNF is equal to a predetermined value ΔNF2 (for example, -80r
pm) or less to a predetermined value ΔNF1 (for example, 60 rpm). That is, here, by setting the clutch oil control amount ta as described above, the front propeller shaft 16 rotates and the clutch gear 20
It is determined whether or not the clutch gear 22 and the clutch gear 22 have been satisfactorily synchronized.

For example, immediately after the control amount ta of the clutch oil pressure is set, the rotational speed difference ΔNF has still exceeded a predetermined value ΔNF1 (for example, 60 rpm), and the determination result of step S616 is false ( No). Therefore,
In such a case, in step S618, the state where the freewheel hub mechanism 19 is kept separated (HAB
= FREE).

When this routine is repeatedly executed, the absolute value | ΔVc | of the rotation difference of the propeller gradually decreases. Then, the next time step S602 is executed, the absolute value | ΔVc |
140 rpm) or less, then step S61
Go to 0. In step S610, the hydraulic multiple disc clutch 8
Then, it is determined whether or not the control amount ta of the clutch oil pressure supplied to 8 is smaller than a predetermined value ta1. The predetermined value ta1 is a control amount of the clutch hydraulic pressure which is minimum necessary for synchronizing the rear propeller shaft and the front propeller shaft 16.

If the result of the determination in step S610 is true (Ye
If the control amount ta of the clutch hydraulic pressure is smaller than the predetermined value ta1 in s), the process proceeds to step S612, where the control value Δta is added to the control amount ta of the clutch hydraulic pressure. Control value Δt
The value a is set in advance to, for example, about 1/256 of the maximum value tamax of the control amount ta. On the other hand, the determination result of step S610 is false (N
If it is determined in step o) that the control amount ta is equal to or greater than the predetermined value ta1, in step S614, the clutch hydraulic control amount t
a is set to a predetermined value ta1. Thus, even if the control amount ta set in step S606 is larger than the predetermined value ta1, the synchronous rotation of the clutch gear 20 and the clutch gear 22 can be adjusted.

Then, in step S616, the rotational speed difference ΔNF is set to a predetermined value ΔNF2 (for example, -8
0 rpm) or more and not more than a predetermined value ΔNF1 (for example, 60 rpm), and if the determination result is false (No), the rotation speed difference ΔNF is not less than a predetermined value ΔNF2 (for example, −80 rpm) and a predetermined value ΔNF1 (for example, If the free wheel hub mechanism 19 is not in the range of 60 rpm or less, the free wheel hub mechanism 19 is maintained in a separated state (HAB = FREE) in step S618.

On the other hand, the result of the determination in step S616 becomes true (Yes), and the rotational speed difference ΔNF becomes a predetermined value ΔNF2
(For example, -80 rpm) or more and a predetermined value ΔNF1 (for example, 6
0 rpm), the clutch gear 20 and the clutch gear 22 are satisfactorily synchronized with each other.
It can be determined that the coupling sleeve 24 can satisfactorily connect the clutch gears 20 and 22. In this case, step S
At 620, the freewheel hub mechanism 19 is set to the connected state, that is, the locked state (HAB = LOCK).

That is, a drive signal is supplied to the electromagnetic switching valve of the vacuum actuator 28 to operate the shift fork 26, whereby the coupling sleeve 24 smoothly moves without generating noise or the like as shown in FIG. The clutch gears 20, 22 are connected to each other. By the way, the determination result of step S602 is false (No), that is, the absolute value | ΔVc |
If it is larger than Vc40 (for example, 140 rpm) and the result of the determination in step S604 is true (Yes), that is, if the rotation speed difference ΔNF is equal to or smaller than a predetermined value ΔNF1 (for example, 60 rpm), the process proceeds to step S608. move on. For example, there may be a case where the vehicle is not traveling normally and the rear wheel RW, which is a driving wheel, slips and the front wheel FW is hardly rotating. In such a case, the clutch gear 20 and the clutch gear 22 are substantially synchronized with each other, and the rotation speed difference ΔNF is equal to or smaller than a predetermined value ΔNF1 (for example, 60 rpm), and the rotation speed of the clutch gear 20 is not further increased. Better. Therefore, the determination result of step S602 is false (No)
, The determination result in step S604 is true (Yes).
And the rotational speed difference ΔNF is a predetermined value ΔNF1 (for example, 60 rpm).
If not, in the next step S608, the control amount ta of the clutch oil pressure is set to zero, and the rotation of the front propeller shaft 16 increases to increase the rotation speed of the clutch gear 20 more than necessary. To prevent

In the determination of step S604, the differential value dΔNF / dt of the rotational speed difference ΔNF is smaller than a predetermined value Y1 (for example, -1000 rpm / sec ² ), that is, the clutch gear 2
It is also determined whether or not the approach rate between the rotation speed of 0 and the rotation speed of the clutch gear 22 is extremely large. If the determination result is true (Yes) and the differential value dΔNF / dt is equal to the predetermined value Y1
Even when the rotation speed of the clutch gear 20 is smaller than (for example, −1000 rpm / sec ² ) and the approach rate of the rotation speed of the clutch gear 20 to the rotation speed of the clutch gear 22 is extremely large, the control amount ta of the clutch oil pressure is set to zero in step S608. That is, in a situation where the rear wheel RW, which is the driving wheel, is slipping, if the rate of approach of the rotation speed of the clutch gear 20 to the rotation speed of the clutch gear 22 is extremely large, the front propeller shaft 16 rotates more than necessary. The inertia force may cause the clutch gear 20 to exceed the rotational speed of the clutch gear 22 and over-rotate. Therefore, here, even if the rotational speed difference ΔNF is not less than the predetermined value ΔNF1 (for example, 60 rpm), the differential value dΔNF / dt is a predetermined value Y1 (for example, -100
0 rpm / sec ² ) If it is smaller than 0, the control amount t of the clutch hydraulic pressure
By setting a to zero, the rotation of the front propeller shaft 16 is suppressed, and the rotation speed of the clutch gear 20 is prevented from increasing more than necessary.

The differential value dΔNF / of the rotational speed difference ΔNF /
If dt is larger than the predetermined value Y1, step S60
4 is false (No), and then step S60
Proceeding to 6, the setting of the clutch hydraulic pressure control amount ta is performed as described above. Further, in step S600, when the determination result is true (Yes), that is, when the vehicle speed V is equal to the predetermined value V
When stopped below 40, the coupling sleeve 2
4 can determine that the clutch gears 20 and 22 can be satisfactorily connected, and the process proceeds to step S620 to bring the freewheel hub mechanism 19 into the connected state (HAB = LOCK).

If the decision result in the step S274 in FIG. 13 is false (No), the process proceeds to a step S278 in which the drive mode command is the 4WD mode (MODE = 4H) and the actual drive mode is the full time 4WD. Between the mode and the high direct connection 4WD mode (actual MODE = 4H-4HLc)
Or high direct connection 4WD mode (actual MODE = 4HLc)
Is determined. If the determination result is true (Yes), the process proceeds to step S280 to perform the direct connection 4WD release process of FIG.

On the other hand, if the decision result in the step S270 is true (Yes), a motor stop process is performed in a step S272. That is, the shift actuator 60
The operation of the electric motor 204 causes the shift fork 84
Moves, and as shown in FIG.
2 is a position (full-time 4WD position) at which the clutch gears 74 and 78 are connected to each other, and if the drive mode command and the actual drive mode match, the 2WD release processing and the direct connection 4WD release processing reverse or rotate. It is no longer necessary to operate the rotated electric motor 204,
4 is stopped.

In the step S282, it is determined whether or not the freewheel hub mechanism 19 is in a free state (HAB = FREE). Actually, when the drive mode command is the 4WD mode (MODE = 4H) and the actual drive mode is also (actual MODE = 4H), the above step S
By executing 620, the freewheel hub mechanism 19 is locked (HAB = LOCK). Therefore,
The determination here is a confirmatory one. If the determination result is true (Yes) and the freewheel hub mechanism 19 is in the free state (HAB = FREE), step S28 is performed.
At 4, the HAB control is performed. As a result, the vehicle is brought into a full-time 4WD state.

In step S286 in FIG. 15, the drive mode command is set to the high direct connection 4WD mode (MODE = 4HLc).
And whether the actual drive mode is also the high direct connection 4WD mode (actual MODE = 4HLc). If the determination result of step S286 is false (No), the process proceeds to step S290, where the drive mode command is set to the high direct connection 4W
In the D mode (MODE = 4HLc) and the actual drive mode is 2WD mode (actual MODE = 2H) or in the same manner as above, the actual drive mode is between the 2WD mode and the full time 4WD mode (actual MODE = 2H-4H). It is determined whether or not there is. If the determination result is true (Yes), the process advances to step S292 to perform the 2WD release processing of FIG.

The determination result of step S290 is false (No)
In the case of, the process proceeds to step S294, in which the drive mode command is high direct connection 4WD mode (MODE = 4HLc) and the actual drive mode is high in full time 4WD mode (real mode = 4H) or full time 4WD mode. Intermediate with direct connection 4WD mode (actual MODE = 4H-4HL)
c) is determined. The judgment result is true (Yes)
In the case of, the process proceeds to step S296.

In step S296, a direct connection 4WD entry process is performed. In the direct connection 4WD entry process, the flowchart of the direct connection 4WD entry process routine shown in FIG. 20 is executed. In step S450 in FIG. 20, a control amount ta of the clutch hydraulic pressure supplied to the hydraulic multiple disc clutch 88 is set. The control amount ta of the clutch hydraulic pressure here is preset according to the absolute value | ΔVc | of the difference in the rotation of the propeller, as shown in the map of FIG. The absolute value | Δ in FIG.
The value X3 of Vc | is, for example, 3 rpm, and the value X4 is, for example, 15 rpm.
rpm.

Thus, the engagement of the hydraulic multi-plate clutch 88 causes the clutch gears 74, 78, 80 to rotate substantially integrally and synchronously, and is brought into a substantially directly connected 4WD state. Then, in the next step S452, the absolute value | ΔVc
It is determined whether or not | is greater than ΔVc50 (for example, 40 rpm). If the determination result is false (No), the absolute value of the
If Vc | is equal to or less than ΔVc50 (for example, 40 rpm), the process proceeds to step S454.

In the step S454, it is determined whether or not the driving force Ftf from the engine 2 to the transfer device 6 is larger than a predetermined value Ftf50. If the determination result is false (No), the driving force Ftf
Is less than or equal to the predetermined value Ftf50, then step S4
Proceed to 56. In step S456, it is determined whether or not the steering wheel angle θH is larger than a predetermined value θH50 (for example, 270 deg) and the vehicle speed V is lower than a predetermined value V50 (for example, 30 km / h). If the determination result is false (No) and the steering wheel angle θH is equal to or smaller than the predetermined value θH50 (eg, 270 deg) and the vehicle speed V is equal to or higher than the predetermined value V50 (eg, 30 km / h), the process proceeds to step S458. Perform operation processing.

That is, the absolute value | ΔVc | of the difference in rotation of the propeller becomes equal to or less than ΔVc50 (for example, 40 rpm), the driving force Ftf is equal to or less than a predetermined value Ftf50, and the steering wheel angle θH is equal to or less than a predetermined value θH50 (for example, 270 deg). If the vehicle speed V is equal to or higher than the predetermined value V50 (for example, 30 km / h), it can be determined that the shift actuator 60 may be operated in accordance with the drive mode command (MODE = 4HLc). The motor 204 is operated in the normal rotation direction.

If the determination results in steps S452, S454, and S456 are each true (Yes), it can be determined that the shift actuator 60 should not be operated. In step S460, motor stop processing is executed, and The motor 204 is kept stopped. On the other hand, if the result of the determination in step S286 is true (Yes), a motor stop process is performed in step S288. That is, the operation of the electric motor 204 of the shift actuator 60 causes the shift fork 84 to move, and as shown in FIG. 33, the coupling sleeve 82 connects all of the clutch gears 74, 78, 80 to each other (directly connected 4WD). Position), and if the drive mode command matches the actual drive mode, the 2W
It is no longer necessary to operate the electric motor 204 rotated forward in the D release processing and the direct connection 4WD plunging processing.
04 is stopped. As a result, the vehicle is brought into the high direct connection 4WD state. In this state, the driving force from the input shaft 8 is not differentially driven by the center
0 and the transfer sprocket 12 (approximately 5:
5) It is transmitted.

Step S46 in FIG. 6 is a step for performing hydraulic control in accordance with the control amount ta set in the # 1 motor control. That is, by executing step S46, the opening and closing of the solenoid valve of the valve body 90 is controlled, and the engagement force of the hydraulic multi-plate clutch 88 is appropriately adjusted (clutch control means). Then, in step S47,
The execution cycle timer TMA is reset to a value of 0.

If the result of the determination in step S42 in FIG. 6 is true (Yes) and the vehicle speed V is lower than the predetermined vehicle speed V0 (for example, 2 km / h), then step S45 is performed.
Proceed to. In step S45, # 2 motor control is performed. This # 2 motor control means the control of the electric motor 204 of the shift actuator 60 when the vehicle is substantially stopped. In # 2 motor control,
The flowchart of the # 2 motor control routine shown in FIGS. 26 to 29 is executed, and will be described below with reference to FIGS. 26 to 29.

In step S300 of FIG. 26, it is determined whether or not the select lever position of the transmission 4 is in the parking range (P range) or the neutral range (N range) based on the information from the inhibitor switch 108. If the determination result is false (No) and the select lever position is not in the P range or the N range, the routine exits without performing any operation. That is, even if the vehicle speed V is lower than the predetermined vehicle speed V0 (for example, 2 km / h), the select lever position of the transmission 4 is in the drive range (D range) or the like, and the driving force of the engine 2 is transmitted to the transfer device 6. In such a situation, the motor control is not performed.

On the other hand, if the decision result in the step S300 is true (Yes) and the select lever position of the transmission 4 is in the P range or the N range, the next step S30
2, the motor protection timer TMm is set to a predetermined time T7.
It is determined whether the value is smaller than 0 (for example, 10 seconds).
If the determination result is true (Yes) and the operation timer TMm has not reached the predetermined time T70 (for example, 10 seconds), the process proceeds to step S304.

In step S304, as in the case of the # 1 motor control, the drive mode command is set to the 2WD mode (M
ODE = 2H) and whether the actual drive mode is also the 2WD mode (actual MODE = 2H). If the determination result of step S304 is false (No), the process proceeds to step S312, where the drive mode command is the 2WD mode (MODE = 2H) and the actual drive mode is 2W.
Intermediate between D mode and full-time 4WD mode (actual MOD
E = 2H-4H) or full-time 4WD mode (actual M
ODE = 4H) is determined. If the determination result is true (Yes), the process proceeds to step S314.

In step S314, a motor reverse movement process is performed. That is, in this case, unlike the case of the # 1 motor control, since the driving force of the engine 2 is not transmitted to the transfer device 6, the coupling sleeve 82 does not easily operate between the clutch gears 74 and 80. Therefore 2
The motor reverse motion process is performed directly without performing the WD rush process.

The determination result of step S312 is false (No)
In the case of, the process proceeds to step S316, where the drive mode command is the 2WD mode (MODE = 2H) and the actual drive mode is the full-time 4WD mode and the high direct connection 4WD.
It is determined whether the mode is an intermediate mode (actual MODE = 4H-4HLc) or a high direct connection 4WD mode (actual MODE = 4HLc). If the determination result is true (Yes),
Next, the process proceeds to step S318.

In step S318, the motor reverse movement process is performed as described above. That is, here, for the same reason as described above, the motor reverse rotation process is performed directly without performing the direct connection 4WD release process. If the decision result in the step S316 is false (N
In the case of o), the process proceeds to step S320, where the drive mode command is the 2WD mode (MODE = 2H) and the actual drive mode is the high direct connection 4WD mode and the low direct connection 4W
It is determined whether the mode is intermediate with the D mode (actual MODE = 4HLc-4LLc) or the row direct connection 4WD mode (actual MODE = 4LLc). If the determination result is true (Yes), the process proceeds to step S322.

In step S322, switching processing between the high direct connection 4WD mode and the low direct connection 4WD mode, that is, Hi-
A Low switching process is performed. In this Hi-Low switching process, the flowchart of the Hi-Low switching process routine shown in FIG. 30 is executed. In step S700 of FIG. 30, the drive mode command is a low direct connection 4WD mode (MODE
= 4LLc). Here, since the drive mode command is the 2WD mode (MODE = 2H), the determination result is false (No), and the next step S70
Then, the process proceeds to step S <b> 2, and a motor reverse rotation command is output to the electric motor 204.

In the next step S706, it is determined whether or not the timer TM1HL for motor protection is equal to or shorter than a predetermined time T80 (for example, 10 seconds). If the determination result is true (Yes), the operation timer TM1HL is set to the predetermined time T80 (for example, 10 seconds).
If not, the timer TM1HL is counted up in step S708. On the other hand, if the determination result of step S706 is false (No) and the timer TM1HL exceeds a predetermined time T80 (for example, 10 seconds),
Next, the process proceeds to step S710, where it is determined whether or not a flag FONOFF, which is an ON-OFF command for the shift actuator 60 at the time of Hi-Low switching, has a value of 1.

If the determination result in the step S710 is true (Ye
If the value of the flag FONOFF is 1 in s), the on-timer TM2HL is counted up in step S712. Then, in a step S716, it is determined whether or not the on-timer TM2HL has reached a predetermined time T90 (for example, 1 sec). If the determination result of step S716 is false (N
In the case of o), it is determined again in step S724 whether the flag FONOFF has the value 1, and in the next step S726, a motor operation command (motor reverse rotation command) corresponding to the output signal of step S702 is output. I do.

On the other hand, if the decision result in the step S716 is true (Yes), in the next step S718,
The flag FONOFF is reset to a value 0, and at the same time, the on-timer TM2HL is reset to a value 0. In this case, the determination result in step S724 is false (No), and a motor stop command is output in the next step S728 to stop the operation of the electric motor 204.

If the value of the flag FONOFF is set to 0, the result of the determination in step S710 is false (No). In this case, in step S714, the off timer TM3HL is counted up. Then, in step S720, the off timer TM3HL sets the predetermined time T92 (for example, 1se
Determine whether or not c). If the determination result in step S720 is false (No), the determination result in step S724 is false (No), and
At 728, the motor stop command is continuously output, and the electric motor 204 is kept stopped.

On the other hand, if the decision result in the step S720 is true (Yes), in the next step S722,
The flag FONOFF is set to the value 1 and the off timer TM3
Reset HL to value 0. Thereby, step S72
The determination result of step 4 is true (Yes), and step S726 is performed.
, A motor operation command (motor reverse rotation command) is output again.

That is, steps S710 to S710
In step 728, the electric motor 204 is set to the predetermined time T.
After operating for 90 (for example, 1 sec), a predetermined time T92
(For example, 1 second), the on / off operation of stopping is repeated. By repeating the on / off operation in this manner, the timer TM1HL is set to the predetermined time T80 (for example, 10 seconds).
In a situation in which the coupling sleeve 56 does not operate smoothly between the clutch gears 40 and 42 even if it exceeds ec), the coupling sleeve 56 operates satisfactorily by the recoil based on the on / off operation.

When the processing routine of steps S314 and S318 in FIG. 26 is executed, the flow advances to step S324 to count up the timer TMm.
When the processing routine of step S322 is executed, the process proceeds to step S326 of FIG. In this way, the motor reverse operation process and the Hi-Low switching process are performed. On the other hand, if the determination result in step S304 is true (Yes), the process proceeds to step S306.
That is, as shown in FIG. 32, when the coupling sleeve 82 is set to the position (2WD position) where the clutch gears 74 and 80 are connected to each other, and the drive mode command and the actual drive mode match, step S306 is performed. 32, the freewheel hub mechanism 19 is set in a free state (HAB = FREE) as shown in FIG. Since it is no longer necessary to operate the electric motor 204, a motor stop process is performed in step S308, and the electric motor 204 operated as described above is stopped. And
In step S310, the timer TMm is reset. As a result, similar to the case of # 1 motor control,
The vehicle is in the 2WD state.

Note that the timer TMm
Exceeds the predetermined time T70 (for example, 10 seconds) and the determination result of step S302 is false (No), the routine exits without performing step S304 and subsequent steps. That is, the timer TMm is set to the predetermined time T7.
0 (for example, 10 seconds), the clutch gears 40, 4
If the operation of the coupling sleeve 56 is not completed between the two, the electric motor 204 is prevented from forcibly rotating. This prevents the electric motor 204 from being damaged due to overheating or the like.

In step S326 in FIG. 27, the drive mode command is the full-time 4WD mode (MODE = 4H) and the actual drive mode is also the full-time 4WD mode (real MODE) as in the case of the # 1 motor control. =
4H). If the determination result of step S326 is false (No), then step S332 is performed.
And the drive mode command is changed to the full-time 4WD mode (M
ODE = 4H) and whether the actual drive mode is the 2WD mode (actual MODE = 2H) or, similarly to the above, the actual drive mode is intermediate between the 2WD mode and the full-time 4WD mode (actual MODE = 2H-4H) Is determined. If the determination result is true (Yes), then step S334 is performed.
Proceed to.

In step S334, a motor operation process is performed. That is, here, for the same reason as above, 2WD
The motor operation processing is performed directly without performing the release processing.
If the determination result of step S332 is false (No),
Next, proceeding to step S336, the drive mode command is set to 4WD.
Mode (MODE = 4H) and the actual drive mode is between the full-time 4WD mode and the high direct connection 4WD mode (actual MODE = 4H-4HLc) or the high direct connection 4WD.
It is determined whether or not the mode (actual MODE = 4HLc). If the result of the determination is true (Yes), the process proceeds to step S338, in which a motor reverse movement process is performed. That is, here, for the same reason as described above, the motor operation processing is directly performed without performing the direct connection 4WD release processing.

The determination result of step S336 is false (No)
In step S340, the process proceeds to step S340 in which the drive mode command is the full-time 4WD mode (MODE = 4H) and the actual drive mode is intermediate between the high direct connection 4WD mode and the low direct connection 4WD mode (actual MODE = 4HLc). -4LL
c) Or low direct connection 4WD mode (actual MODE = 4LL)
c) is determined. The judgment result is true (Yes)
In the case of, the process proceeds to step S342.

In step S342, the above-mentioned Hi-Low
A switching process is performed. The control procedure in the Hi-Low switching process is the same as above, and the description is omitted here. When the processing routine of steps S334 and S338 is executed, the process proceeds to step S344, and the timer T
Count up Mm. When the processing routine of step S342 is executed, step S35 of FIG.
Go to 0.

In this manner, the motor operation processing, the motor reverse movement processing, and the Hi-Low switching processing are performed. If the determination result of step S326 is true (Yes), the next step is performed. Proceed to S328. That is, the operation of the electric motor 204 of the shift actuator 60 causes the shift fork 84 to move toward the rear wheel output shaft 10, and the coupling sleeve 82 connects the clutch gears 74 and 78 to each other as shown in FIG. When the drive mode command matches the actual drive mode, the electric motor 204 does not need to be operated anymore. Therefore, the motor stop processing is performed in step S328, and The operated electric motor 204 is stopped. Then, in step S330, the timer TMm is reset.

Further, in step S346, the freewheel hub mechanism 19 is in the free state (HAB = FRE).
E) is determined. The judgment result is true (Yes)
And the freewheel hub mechanism 19 is in a free state (HAB =
(FREE), the HAB control is performed in step S348, and the freewheel hub mechanism 19 is locked (HAB = LOCK). This allows
As in the case of the # 1 motor control, the vehicle is set to the full-time 4WD state.

In step S350 in FIG. 28, as in the case of # 1 motor control, the drive mode command is the high direct connection 4WD mode (MODE = 4HLc) and the actual drive mode is also the high direct connection 4WD mode (real MODE). =
4HLc). Step S350
Is negative (No), then step S3
Proceeding to 56, the drive mode command is the high direct connection 4WD mode (MODE = 4HLc) and the actual drive mode is 2
It is determined whether the WD mode (actual MODE = 2H) or the actual driving mode is intermediate between the 2WD mode and the full-time 4WD mode (actual MODE = 2H-4H) as described above. If the result of the determination is true (Yes), the process proceeds to step S358 to perform a motor operation process. That is, here, for the same reason as described above, the motor operation process is directly performed without performing the 2WD cancellation process.

The determination result of step S356 is false (No)
In step S360, the process proceeds to step S360, in which the drive mode command is high direct connection 4WD mode (MODE = 4HLc) and the actual drive mode is high in full time 4WD mode (real mode = 4H) or full time 4WD mode. Intermediate with direct connection 4WD mode (actual MODE = 4H-4HL)
c) is determined. The judgment result is true (Yes)
In the case of, the process proceeds to step S362.

In step S362, a motor operation process is performed. That is, here, for the same reason as above, the direct connection 4
The motor operation process is performed directly without performing the WD rush process. If the determination result in step S360 is false (No), the process proceeds to step S364, in which the drive mode command is the high direct connection 4WD mode (MODE = 4HLc) and the actual drive mode is the high direct connection 4WD mode and the low direct connection. 4W
It is determined whether the mode is intermediate with the D mode (actual MODE = 4HLc-4LLc) or the row direct connection 4WD mode (actual MODE = 4LLc). If the determination result is true (Yes), the process proceeds to step S366.

In step S366, the Hi-Low
A switching process is performed. The control procedure in the Hi-Low switching process is the same as above, and the description is omitted here. Then, when the processing routine of step S358 and step S362 is executed, the process proceeds to step S368.
The timer TMm is counted up. Step S
When the processing routine of 366 is executed, the flow proceeds to step S370 in FIG.

Thus, the motor operation processing, Hi-L
The ow switching process is to be performed.
If the determination result at 50 is true (Yes), the process proceeds to step S352. That is, as shown in FIG. 33, the coupling sleeve 82 is connected to the clutch gears 74, 78, 80.
Are connected to each other (directly connected 4WD position), and when the drive mode command and the actual drive mode match, it is no longer necessary to operate the electric motor 204, so the motor stop processing is executed in step S352. Do
The electric motor 204 operated as described above is stopped. Then, in a step S354, the timer TMm is reset. As a result, as in the case of the # 1 motor control, the vehicle is brought into the high direct connection 4WD state, and the input shaft 8
The driving force is equally distributed (approximately 5: 5) to the rear wheel output shaft 10 and the transfer sprocket 12 without differential by the center differential 62 and transmitted.

In step S370, the drive mode command is the low direct connection 4WD mode (MODE = 4LLc), and the actual drive mode is also the low direct connection 4WD mode (real MODE).
= 4LLc). Step S37
If the determination result of 0 is false (No), then step S
Proceeding to 376, the drive mode command is low direct connection 4WD mode (MODE = 4LLc) and the actual drive mode is 2
The WD mode (actual MODE = 2H) or the actual driving mode is intermediate between the 2WD mode and the full-time 4WD mode (actual M
It is determined whether or not ODE = 2H-4H). If the determination result is true (Yes), the process proceeds to step S378 to perform a motor operation process.

The determination result of step S376 is false (No)
In step S380, the process proceeds to step S380, in which the drive mode command is low direct connection 4WD mode (MODE = 4LLc) and the actual drive mode is full-time 4WD mode (actual MODE = 4H) or full-time 4WD mode and high. Intermediate with direct connection 4WD mode (actual MODE = 4H-4HL)
c) is determined. The judgment result is true (Yes)
In the case of, the process proceeds to step S382 to perform a motor operation process.

The determination result of step S380 is false (No)
In step S384, the driving mode command is the low direct connection 4WD mode (MODE = 4LLc) and the actual driving mode is the high direct connection 4WD mode (real M).
ODE = 4HLc) or intermediate between the high direct connection 4WD mode and the low direct connection 4WD mode (actual MODE = 4HLc-4L)
Lc). If the determination result is true (Ye
In the case of s), the process proceeds to step S386.

In step S386, the Hi-Low
A switching process is performed. Also in this case, Hi-Lo of FIG.
The w switching process routine is executed, provided that the determination result of step S700 in FIG. 30 is true (Ye
s), and in this case, a motor normal rotation command is output to the electric motor 204 in the next step S704. Step S706 and subsequent steps are as described above, and the description is omitted.

Then, step S378, step S3
When the processing routine of 82 is executed, step S388 is performed.
To count up the timer TMm. Thus, the motor operation process and the Hi-Low switching process are performed. If the determination result of step S370 is true (Yes), the process proceeds to step S372.
That is, as shown in FIG.
2 is a position for connecting all of the clutch gears 74, 78, 80 to each other (directly connected 4WD position), and a coupling sleeve 56 is a position for connecting the clutch gears 42, 44 to each other (low position). If the drive mode command and the actual drive mode match, the electric motor 204 does not need to be operated anymore, so a motor stop process is performed in step S372 to stop the electric motor 204 operated as described above. Then, step S3
At 74, the timer TMm is reset. As a result, the vehicle is brought into the low direct connection 4WD state. In this state, the driving force from the input shaft 8 is applied to the rear wheel output shaft 10 and the transfer sprocket 12 without differential by the center differential 62.
The transmission is equally distributed (approximately 5: 5) to the transmission and the torque that is more torqueful than the high direct connection 4WD state
Wheel drive (front and rear wheel drive) traveling is enabled.

By the way, the transfer device 6 used in the above embodiment is not limited to the one having the above configuration, but may be as shown in FIG. 35 (second embodiment), FIG. 36 (third embodiment), and FIG. 37 (fourth embodiment). It may be of a configuration. Hereinafter, Examples 2 to 4 will be described. Note that these embodiments differ only in the configuration of the transfer device, and drive switching control (drive switching command means, connection switching means, clutch control means) is the same as that in the first embodiment, so that a detailed description will be given here. Is omitted.

In the second embodiment (corresponding to claim 1), FIG.
As shown in (1), the transfer device does not have the center differential 62 as in the first embodiment, and can switch between the 2WD state, the 4WD state by the clutch connection (on-demand 4WD state), and the direct connection 4WD. That is,
In the second embodiment, a clutch gear 78a and a clutch gear 78a are provided at the other end of a sleeve shaft (second transmission member) 76a rotatably supported by the intermediate shaft (first transmission member) 36.
The clutch gear 80 is provided on the intermediate shaft 36 adjacent to. Further, outside the clutch gears 78a, 80, a coupling sleeve (connection means) 82a for connecting the clutch gears 78a, 80 is arranged. The coupling sleeve 82a is slidable in the axial direction of the intermediate shaft 36. Supported. Then, the intermediate shaft 36 and the sleeve shaft 76
a hydraulic multi-plate clutch (clutch means) 88 is disposed between the clutch gear 78a and the hydraulic multi-plate clutch 88 to transmit a driving force to the front wheel FW side at a portion of the sleeve shaft 76a. An output sprocket 85a is provided.

Therefore, in the case of the transfer apparatus of the second embodiment, the coupling between the clutch gears 78a and 80 is not performed by the coupling sleeve 82a and the hydraulic pressure is not supplied to the hydraulic multiple disc clutch 88 based on the drive switching control. In this state, the driving force is transmitted only to the rear wheel RW side, and the transfer device is in the 2WD state. When hydraulic pressure is supplied to the hydraulic multi-plate clutch 88, the driving force is also transmitted to the front wheel FW side, so that the on-demand is performed. The 4WD state is set. Thus, similarly to the first embodiment, the clutch gears 78a and 80 are formed by the coupling sleeve 82a.
The driving force is transmitted to the sleeve shaft 76a and the output sprocket 85a even before the connection between them is performed. In addition, when the coupling is performed by the coupling sleeve 82a, the coupling sleeve 82a moves smoothly without abnormal noise, and the transfer device is satisfactorily brought into the direct connection 4WD state.

In the third embodiment (corresponding to claim 7), FIG.
As shown in (1), the transfer device has a center differential 62 as in the first embodiment, and in this case, switching between full-time 4WD and direct connection 4WD is possible. That is, in the case of the third embodiment, the center differential 6
A hydraulic multi-plate clutch 88 is disposed between the second differential case 64 and a sleeve shaft 72a rotatably supported on the intermediate shaft 36. A clutch gear 74a is provided at one end of the sleeve shaft 72a, and at an intermediate portion thereof. An output sprocket 85b for transmitting the driving force to the front wheel FW side is provided. Further, a coupling sleeve (third coupling means) 82b for coupling the clutch gear 74a to the clutch gear 80 is disposed outside the clutch gear 80 provided on the clutch gear 74a and the intermediate shaft 36. Reference numeral 82b is slidably supported in the axial direction of the intermediate shaft 36.

Accordingly, in the case of the transfer device of the third embodiment, the clutch gear 74a and the clutch gear 80a are driven by the coupling sleeve 82b based on the drive switching control.
In the state where the connection is not made and the hydraulic pressure is not supplied to the hydraulic multiple disc clutch 88, the driving force is appropriately distributed to the front wheel FW side and the rear wheel RW side by the center differential 62, and the transfer device is in the full time 4WD state. (Not directly connected)
When the hydraulic pressure is supplied to the hydraulic multi-plate clutch 88, the on-demand 4WD state is set. As a result, similarly to the first embodiment, the clutch gear 74a and the clutch gear 80 rotate synchronously, and the coupling between the clutch gears 74a and 80 is performed by the coupling sleeve 82b. The ring sleeve 82b moves smoothly without abnormal noise, and the transfer device is satisfactorily brought into the direct connection 4WD state (direct connection state).

In the fourth embodiment (corresponding to claim 7), FIG.
As shown in FIG. 11, the transfer device has a center differential 62 as in the first and third embodiments. In this case, the transfer device has 2WD and full-time 4WD as in the first embodiment.
And the direct connection 4WD can be switched. That is, in the case of the fourth embodiment, as in the case of the third embodiment, the hydraulic multiple disc clutch 88 is disposed between the differential case 64 of the center differential 62 and the sleeve shaft 72b rotatably supported on the intermediate shaft 36. The clutch gear 74b is provided at one end of the sleeve shaft 72b. Further, a sleeve shaft 76b is rotatably supported by the sleeve shaft 72b, a clutch gear 78b is provided at one end of the sleeve shaft 76b, and an output sprocket 85c for transmitting driving force to the front wheel FW is provided at the other end. Have been. The clutch gear 74b and the clutch gear 78b
A coupling sleeve (third coupling means) 82c for coupling the clutch gears 74b and 80 to the outside of the clutch gear 80 provided on the intermediate shaft 36 and a clutch gear 74.
A coupling sleeve 82d for connecting the first and second coupling sleeves b and 78b is provided.
82d is slidably supported in the axial direction of the intermediate shaft 36.

Accordingly, in the case of the transfer device of the fourth embodiment, the clutch gear 74b and the clutch gear 80b are driven by the coupling sleeve 82c based on the drive switching control.
When the clutch gear 74b and the clutch gear 78b are not connected by the coupling sleeve 82d, the driving force is transmitted only to the rear wheel RW side, and the transfer device is in the 2WD state. When the clutch gear 74b and the clutch gear 80 are not connected by the coupling sleeve 82c, but the clutch gear 74b and the clutch gear 78b are connected by the coupling sleeve 82d, the transfer device is in a full-time 4WD state. (Non-direct connection state). Then, for example, when the hydraulic pressure is supplied to the hydraulic multiple disc clutch 88 in this state, the on-demand 4WD state is set.
As a result, similarly to the first embodiment, the clutch gear 74b and the clutch gear 80 rotate synchronously, and when the coupling between the clutch gears 74b and 80 is performed by the coupling sleeve 82c, the The ring sleeve 82c moves smoothly without abnormal noise, and the transfer device is satisfactorily brought into the direct connection 4WD state (direct connection state).

In the fourth embodiment, the coupling sleeve 82c and the coupling sleeve 82d are separated from each other. However, these can be constituted by one coupling sleeve as in the first embodiment. . As described above, in the front-rear wheel drive vehicle of the present invention, when the actual drive mode is the 2WD mode (actual MODE = 2H), the actual drive mode is changed to the full-time 4WD in response to the drive mode command (MODE = 4H). In the mode (actual MODE = 4H), as shown in FIG. 18, the absolute value | ΔV
If c | is larger than ΔVc30 (for example, 30 rpm) and the rotational speed difference between the clutch gear 74 and the clutch gear 78 is large (step S436), the driving force Ftf is larger than the predetermined value Ftf30. When the driving force applied to the clutch gear 78 is large (step S438), the steering wheel angle θH is larger than a predetermined value θH30 (for example, 180 deg similarly to the predetermined value θH10) and the vehicle speed V is set to a predetermined value V3.
When the vehicle is in a low-speed turning state that is smaller than 0 (for example, 25 km / h similarly to the predetermined value V10) (step S44)
0), the drive motor 20 of the shift actuator 60
4 is not operated (step S444), that is, the clutch gear 7 is operated without operating the coupling sleeve 82.
4 and the clutch gear 78 are prohibited, and during this time, the clutch hydraulic pressure of the control amount ta is supplied to the hydraulic multi-plate clutch 88 so that the clutch is in the 4WD state (on demand 4).
(WD state) (step S4).
34).

Therefore, when the prohibition condition is canceled and the drive motor 204 becomes operable to connect the clutch gear 74 and the clutch gear 78 (step S442), the clutch gear 74 and the clutch gear 78 are properly connected. Synchronization means that abnormal noise generation and breakage of the clutch gears 74, 78 and the like are well prevented without collision between the coupling sleeve 82 and the clutch gears 74, 78, and switching of the drive mode is extremely performed. It can be realized smoothly.

At this time, since the control amount ta of the clutch oil pressure supplied to the hydraulic multi-plate clutch 88 is set according to the absolute value | ΔVc | of the rotation difference of the propeller (see FIG. 19),
Switching of the drive mode is realized smoothly and extremely quickly.

[0202]

As described in detail above, claim 1 is as follows.
According to the front and rear wheel drive vehicle of the first aspect, since the connection switching operation between the first transmission member and the second transmission member of the connection means by the connection switching means is not actually performed, the first engagement is performed by the engagement of the clutch means.
The driving force can be transmitted from the transmitting member to the second transmitting member, and the driving force can be quickly transmitted to the front and rear wheels.
Thereafter, by performing the connection switching operation of the connection means, a desired drive mode can be suitably achieved.

According to the front and rear wheel drive vehicle of the second aspect,
The second output element of the first connection means and the third
The driving force can be transmitted from the input element or the first output element to the third transmission member by engagement of the clutch means from a time before the connection switching operation with the transmission member is actually performed, and the driving force can be quickly transmitted to the front and rear wheels. The drive force can be transmitted, and then the connection switching operation of the first connection means is performed, whereby a desired drive mode can be suitably achieved.

Further, according to the front and rear wheel drive vehicle of claim 3,
The driving force is transmitted to the front and rear wheels in a state close to a direct connection state in which the differential of the differential device is limited by engagement of the clutch means from a time before the connection switching operation of the second connection means by the connection switching means is actually performed. Can quickly limit the front and rear wheel differential, and then perform the connection switching operation of the second connection means,
A desired drive mode can be suitably achieved.

According to the front and rear wheel drive vehicle of the fourth aspect,
Front and rear wheel rotational speed difference, that is, between the first transmission member and the second transmission member (Claim 1), between the second output element and the third transmission member (Claim 2), or an element connected by the second connection means The engagement of the clutch means is appropriately controlled in accordance with the magnitude of the rotational speed difference between the first transmission member and the second transmission element, or between the second transmission element and the second transmission element. Synchronization with the three transmitting members or with the elements connected by the second connecting means is quickly realized. Therefore, the connecting operation of the connecting means (Claim 1), the first connecting means (Claim 2) and the second connecting means (Claim 3) can be performed more smoothly, and the desired drive mode can be achieved more quickly. can do.

According to the front and rear wheel drive vehicle of claim 5,
Before the connection switching operation of the first connection means or the second connection means by the connection switching means is actually performed, transmission of the driving force from the input element or the first output element to the third transmission member by engagement of the clutch means, Alternatively, it is possible to quickly limit the differential of the differential device, and thereafter, when the connection determination unit determines that the connection is possible and the connection switching operation is performed, the connection switching operation can be smoothly realized without abnormal noise or the like. Can be suitably achieved.

According to the front and rear wheel drive vehicle of claim 6,
When the input torque is smaller than the specified value, it is determined that the first connection means or the second connection means can be connected, that is, the input element, the first output element, and the second output element of the differential device. When a large driving force load is applied to the output element and the third transmission member, it is determined that the connection cannot be accurately performed. Therefore, the connection switching operation of the first connection means and the second connection means is preferably inhibited and the first connection means is appropriately inhibited. Breakage of the connecting means and the second connecting means can be satisfactorily prevented.

According to the front and rear wheel drive vehicle of claim 7,
From the time before the connection switching operation of the third connection means is actually performed by the connection switching means, the differential of the differential device can be limited by the engagement of the clutch means, and the same driving force can be quickly applied to the front and rear wheels. The desired drive mode can be suitably achieved by transmitting the signal and then performing the connection switching operation of the third connection means.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing a drive system of a four-wheel drive vehicle (front and rear wheel drive vehicle) of the present invention.

FIG. 2 is a control block diagram showing a control system of a four-wheel drive vehicle (front and rear wheel drive vehicles).

FIG. 3 is a cross-sectional view of the transfer device according to the first embodiment shown in FIG.

FIG. 4 is a part of a flowchart showing a main routine of drive switching control.

FIG. 5 is the remaining part of the flowchart showing the main routine of the drive switching control, following the flowchart of FIG. 4;

FIG. 6 is the remaining part of the flowchart showing the main routine of drive switching control following the flowchart of FIG. 5;

FIG. 7 is a part of a flowchart showing a 2WD cancellation condition routine in FIG. 5;

FIG. 8 is the remaining part of the flowchart showing the 2WD cancellation condition routine that follows the flowchart of FIG. 7;

FIG. 9 is a part of a flowchart showing a 2WD entry condition routine in FIG. 5;

FIG. 10 is the remaining part of the flowchart showing the 2WD entry condition routine that follows the flowchart of FIG. 9;

FIG. 11 is a flowchart showing a direct connection 4WD entry condition routine in FIG. 5;

FIG. 12 is a flowchart showing a direct connection 4WD cancellation condition routine in FIG. 5;

FIG. 13 is a part of a flowchart showing a # 1 motor control routine in FIG. 6;

FIG. 14 is the remaining part of the flowchart showing the # 1 motor control routine following the flowchart of FIG. 13;

FIG. 15 is the remaining part of the flowchart showing the # 1 motor control routine following the flowchart of FIG. 14;

FIG. 16 is a flowchart showing a 2WD rush processing routine in FIG. 13;

FIG. 17 is a flowchart showing a direct connection 4WD release processing routine in FIG. 13;

FIG. 18 is a flowchart showing a 2WD release processing routine in FIG. 14;

FIG. 19 is a graph showing the relationship between the absolute value | ΔVc | of the difference in the rotation of the propeller and the clutch hydraulic pressure control amount ta in the 2WD release processing.

20 is a flowchart showing a direct connection 4WD entry processing routine in FIG.

FIG. 21 is a graph showing a relationship between an absolute value | ΔVc | of a rotation difference of a propeller and a clutch hydraulic pressure control amount ta in a direct connection 4WD plunging process.

FIG. 22 is a flowchart showing a motor reverse rotation processing routine.

FIG. 23 is a flowchart showing a motor operation processing routine.

FIG. 24 is a flowchart showing a HAB control routine.

FIG. 25 is a graph showing a relationship between a rotational speed difference ΔNF and a clutch hydraulic pressure control amount ta in HAB control.

FIG. 26 is a part of a flowchart showing a # 2 motor control routine in FIG. 6;

FIG. 27 is the remaining part of the flowchart showing the # 2 motor control routine following the flowchart of FIG. 26;

FIG. 28 is the remaining part of the flowchart showing the # 2 motor control routine following the flowchart of FIG. 27;

FIG. 29 is the remaining part of the flowchart showing the # 2 motor control routine following the flowchart of FIG. 28;

FIG. 30 is a flowchart showing a Hi-Low switching processing routine.

FIG. 31 is a graph showing a relationship between Ftf10 (or Ftf30) and vehicle speed V.

FIG. 32 is a diagram showing a 2WD state.

FIG. 33 is a diagram illustrating a high direct connection 4WD state.

FIG. 34 is a view showing a row direct-coupled 4WD state.

FIG. 35 is a schematic configuration diagram illustrating a transfer device according to a second embodiment.

FIG. 36 is a schematic configuration diagram illustrating a transfer device according to a third embodiment.

FIG. 37 is a schematic configuration diagram illustrating a transfer device according to a fourth embodiment.

[Explanation of symbols]

Reference Signs List 6 transfer device 8 input shaft 10 rear wheel side output shaft 14 rear wheel differential device 16 front propeller shaft 18 front wheel differential device 19 freewheel hub mechanism 20 clutch gear 22 clutch gear 24 coupling sleeve 28 vacuum actuator 36 intermediate shaft (first transmission) 38) auxiliary transmission mechanism 40 clutch gear 42 clutch gear 44 clutch gear 56 coupling sleeve 60 shift actuator (connection switching means) 62 center differential (differential device) 64 differential case (first output element) 70 carrier (input element) 72 inner Sleeve shaft (second output element) 74 Clutch gear 76 Outer sleeve shaft (third transmission member) 76a Sleeve shaft (second transmission member) 78 Clutch gear 80 Clutch gear 82 Cup Ring sleeve (first connection means and second connection means) 82a Cup link sleeve (connection means) 82b Coupling sleeve (third connection means) 82c Coupling sleeve (third connection means) 82d Coupling sleeve 85, 85a, 85b , 85c Output sprocket 88 Hydraulic multi-plate clutch (clutch means) 90 Valve body 94 Electronic control unit (ECU) 96 Front and rear G sensor 98 Throttle opening sensor 100 Handle angle sensor 102 Rotation speed sensor (Front and rear wheel rotation speed difference detection means) 106 Rotation speed sensor (front and rear wheel rotation speed difference detecting means) 108 Inhibitor switch 112 Brake switch 114 Transfer position switch 115 Drive mode changeover switch 202 Motor unit 204 Electric motor

Claims (7)

[Claims] 1. A first transmission member which constantly transmits a driving force from an engine and transmits the driving force to a first wheel, which is one of a front wheel and a rear wheel, and a coupling means to the first transmission member via a connecting means. A second transmission member that is provided so as to be connectable and transmits the driving force to a second wheel that is the other of the front wheel and the rear wheel; and a second transmission member that is provided in parallel with the coupling means, and the first transmission member and the second transmission member are engaged with each other. Clutch means capable of connecting to the second transmission member; a driving state of the vehicle, a two-wheel driving state by the first wheel, and a front and rear wheel by the first and second wheels according to a driver's operation or a running state of the vehicle. Drive switching command means for outputting a switching signal to switch to the driving state, connection switching means for switching the connecting means between a connected state and a non-connected state based on a switching signal from the driving switching command means, and the drive switching command hand When the switching signal from the two-wheel drive state to the front-rear wheel drive state is output from the clutch unit, the clutch unit switches until the connection unit connects the first transmission member and the second transmission member by the connection switching unit. And a clutch control means for controlling engagement of the front and rear wheels. 2. An input element to which a driving force from an engine is input, a first output element that outputs the driving force to a first wheel that is one of a front wheel or a rear wheel, and a first output element that is the other of a front wheel or a rear wheel. A differential device having a second output element for outputting to two wheels, a third transmission being provided so as to be connectable to the second output element via first connection means, and transmitting a driving force to the second wheel. A member, a second connection unit capable of connecting any two of the input element and the first and second output elements, and engaging the third transmission member with the input element or the first output element. A clutch means that can be connected, and a drive state of the vehicle is switched between a two-wheel drive state by the first wheel and a front and rear wheel drive state by the first and second wheels according to a driver's operation or a running state of the vehicle. A drive wheel switching signal is output, and the difference In order to switch between a non-direct connection state in which the differential of the device is allowed to be transmitted to the first and second wheels and a direct connection state in which the differential is prohibited and the transmission is transmitted to the first and second wheels. Drive switching command means for outputting a direct connection switching signal; and the first switching command means based on a switching signal from the drive switching command means.
Connection switching means for switching the connection means or the second connection means between a connection state and a non-connection state; and when the second connection means is in the connection state, the drive switching command means changes the front and rear wheels from the two-wheel drive state. When the driving wheel switching signal to the driving state is output, the clutch for controlling the engagement of the clutch means until the first connection means connects the second output element and the third transmission member by the connection switching means. A front-rear wheel drive vehicle comprising: a control unit. 3. The clutch control means, when the first connection means is in a connected state and the second connection means is in a non-connected state, is controlled by the drive switching command means to change from the non-directly connected state to the directly connected state. When a direct connection switching signal is output, engagement control of the clutch means is performed by the connection switching means until the second connection means connects the input element and any two of the first and second output elements. The front and rear wheel drive vehicle according to claim 2, characterized in that: 4. The clutch control means includes front and rear wheel rotation speed difference detection means for detecting a front and rear wheel rotation speed difference, and controls engagement of the clutch means according to the front and rear wheel rotation speed difference. The front and rear wheel drive vehicle according to any one of claims 1 to 3. 5. The connection switching means outputs a drive wheel switching signal from the two-wheel drive state to the front and rear wheel drive state or a direct connection switch signal from the non-direct connection state to the direct connection state by the drive switching instruction means. And a connection determining means for determining whether the first connecting means or the second connecting means can be connected. When the connection determining means determines that connection is possible, the first connecting means or the second connecting means 4. The clutch control device according to claim 2, wherein the clutch control means controls engagement of the clutch means at least until the connection determination means determines that connection is possible. Wheel drive vehicles. 6. The connection determining means includes an input torque calculating means for calculating an input torque to an input element of the differential and any one of the first and second output elements or the third transmission member. 6. The front and rear wheel drive vehicle according to claim 5, wherein when the input torque is smaller than a specified value, it is determined that connection is possible. 7. An input element for inputting a driving force from an engine, a first output element for outputting the driving force to a first wheel that is one of a front wheel or a rear wheel, and a first output element that is the other of a front wheel or a rear wheel. A differential device having a second output element for outputting to two wheels; a third connecting means capable of connecting any two of the input element and the first and second output elements; And a clutch means capable of connecting any two of the first and second output elements, and a driving state of the vehicle that permits the differential of the differential device according to a driver's operation or a running state of the vehicle. Switching to output a switching signal to switch between a non-direct connection state transmitting to the first wheel and the second wheel and a direct connection state transmitting to the first wheel and the second wheel while inhibiting the differential. Command means; and the drive switching command means. Based on said switching signal No. 3
A connection switching means for switching the connection means between a connection state and a non-connection state; and a third connection by the connection switching means when the drive switching command means outputs a switching signal from the non-direct connection state to the direct connection state. A front / rear wheel drive vehicle, comprising: clutch control means for controlling engagement of the clutch means until the means connects any two of the input element and the first and second output elements.