JPH0886352A - Start control device for continuously variable transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] In a start control device for a continuously variable transmission provided with a fluid transmission device having a lock-up mechanism, without making a lock-up impossible region at the time of start in a lock-up sticking failure state. To achieve stalling avoidance. A shift control valve f having a reference position on a shift spool for commanding a low gear ratio and forcibly releasing a lockup mechanism b regardless of other conditions, and a shift control valve when starting While the speed change spool of f is moved from the reference position to the low gear ratio position side,
The starting control means j is provided for outputting a command to the gear ratio control actuator g to return the gear shift spool from the low gear ratio position to the reference position when the detected engine speed equivalent value falls below the engine stall allowable value.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a start control device for a continuously variable transmission provided with a fluid transmission device having a lockup mechanism.

[0002]

2. Description of the Related Art Conventionally, as a control device for a continuously variable transmission which prevents the lock-up mechanism from sticking when the vehicle is stopped, Japanese Patent Laid-Open Publication No. Hei 4 (1998) -1998
The one described in Japanese Patent No. 78365 is known.

In this reference, there are a low gear ratio position and a high gear ratio position for realizing a gear ratio range used in the gear ratio control during traveling, and a position for instructing a low gear ratio, as well as other conditions. A shift control valve having a reference position for forcibly releasing the lock-up mechanism to the shift spool is shown.When the vehicle is stopped, the shift spool is set to the reference position by the step motor, and the lock-up mechanism is forcibly released. Therefore, there is proposed a technique for preventing the lockup mechanism from sticking when the vehicle is stopped.

[0004]

However, in the above-mentioned conventional start control device for a continuously variable transmission, the lockup solenoid and the lockup control valve are not normally operated in the lockup engaged state. If a sticking failure occurs, the engine and the continuously variable transmission are directly connected by the lock-up mechanism when the shift spool is moved from the reference position to the low gear ratio position, so the engine will rotate regardless of the accelerator operation. There is a problem that the number gradually decreases due to a large load, and the engine eventually stops.

Therefore, in order to solve the above problem, FIG.
As shown in Fig. 6, the lock-up prohibition area for forcibly releasing the lock-up mechanism is replaced with the conventional area setting from the reference position to the front of the low gear ratio position as shown in Fig. If the range is set to exceed the range, the lockup mechanism will be forcibly released even when the gearshift spool is moved from the reference position to the low gear ratio position when the vehicle starts, so the engine will not start when the vehicle is started in the lockup sticking failure state. Stop can be prevented.

However, when the lockup prohibition region for avoiding engine stall is set to a region exceeding the low gear ratio position as described above, the lockup possible region during traveling is narrowed as shown in FIG. As a result, the original purpose of improving fuel efficiency by adopting the lockup mechanism is lost.

The present invention has been made in view of the above problems. A first object of the present invention is to provide a lock control system for a start control device of a continuously variable transmission provided with a fluid transmission device having a lock-up mechanism. It is to achieve engine stall avoidance without creating a lock-up impossible area at the time of starting in the up-stuck failure state.

In addition to the first purpose, the second purpose is to smoothly return to the traveling speed ratio control after the vehicle has started.

The third object is to improve the accuracy of detecting the lock-up fixation failure state at the time of starting, in addition to the first and second objects.

The fourth object is to achieve the engine stall avoidance regardless of the accelerator operation amount at the time of starting, in addition to the first to third objects.

[0011]

In order to achieve the above first object, a start control device for a continuously variable transmission according to the first invention is connected to an engine a as shown in the claim correspondence diagram of FIG. A continuously variable transmission d provided with a fluid transmission c having a lock-up mechanism b, a lock-up control hydraulic circuit e for hydraulically controlling lock-up engagement and lock-up release of the lock-up mechanism b, and a gear shift during traveling. The low gear ratio position and the high gear ratio position for realizing the gear ratio range used in the ratio control, and the position for commanding the low gear ratio, and the lockup mechanism b is forcibly released regardless of other conditions. A shift control valve f having a reference position for controlling the shift spool, a gear ratio control actuator g for driving the shift spool by an external command, and whether or not the vehicle is starting And the advanced time detecting means h, the engine speed corresponding value detecting means i for detecting an engine speed corresponding value,
When the detected engine speed equivalent value falls below the allowable engine stall value while the shift spool of the shift control valve f is moved from the reference position to the low gear ratio position at the time of start, the shift spool is shifted to the low shift position. And a starting control means j for outputting a command for returning from the specific position to the reference position to the gear ratio control actuator g.

In order to achieve the above-mentioned second object, in the starting control system for a continuously variable transmission according to the second invention, as shown in the claim correspondence diagram of FIG. In the device, when the vehicle speed detection value from the vehicle speed detection means k reaches the engine stall avoidance setting value while the speed change spool is returned to the reference position by the starting control means j, the speed change spool is moved from the reference position to the low gear ratio position. It is characterized in that a gear ratio control returning means m for returning and returning to a normal gear ratio control is provided.

In order to achieve the above-mentioned third object, the start control device for a continuously variable transmission according to the third aspect of the present invention, as shown in the claim correspondence diagram of FIG. In the start control device of the aircraft, the start control means j
Is detected when the vehicle speed detection value from the vehicle speed detection means k reaches the measurement error avoidance setting value when the speed change spool of the speed change control valve f is moved from the reference position to the low gear ratio position side at the start. When the corresponding engine speed equivalent value falls below the allowable engine stall value, a command for returning the speed change spool from the low speed ratio position to the reference position is issued to the speed ratio control actuator g.
It is characterized in that it is a means for outputting to.

In order to achieve the fourth object, the start control device for a continuously variable transmission according to the fourth aspect of the present invention, as shown in the claim correspondence diagram of FIG. In the start control device of the aircraft, the engine stall allowable value used by the start control means j for the lock-up sticking failure determination at start is set to a larger value as the throttle opening detection value from the throttle opening detection means n is larger. An engine stall allowance value setting means o is provided.

[0015]

The operation of the first invention will be described.

When it is detected by the starting time detecting means h that the vehicle is starting, the speed change spool of the speed change control valve f is moved from the reference position to the low speed ratio position by a command to the speed change ratio control actuator g. While the shift spool is moved from the reference position to the low gear ratio position, if the engine rotation speed equivalent value detected by the engine rotation speed equivalent value detecting means i falls below the allowable engine stall value, the starting control means j At, the command for returning the gear change spool from the low gear ratio position to the reference position is output to the gear ratio control actuator g.

Therefore, when the lock-up mechanism b of the hydraulic power transmission device c is in the lock-up fixed state for some reason and remains in the lock-up engaged state even if the lock-up mechanism b is moved to the low gear ratio position when starting, A drive system load including the continuously variable transmission d is applied and the engine speed is reduced. However, when the engine speed equivalent value falls below the engine stall allowable value, the speed change spool of the speed change control valve f shifts from the low speed ratio position to the reference position. Since it is returned, the lockup mechanism b is forcibly released at the reference position, the drive system load applied to the engine a is reduced, and then the engine speed increases.

The operation of the second invention will be described.

The vehicle speed detection value from the vehicle speed detection means k becomes the engine stall avoidance set value in a state in which the speed change spool of the speed change control valve f is returned to the reference position at the time of start by the start time control means j of the first invention. When it reaches, in the gear ratio control returning means m, the gear shift spool of the gear shift control valve f is returned from the reference position to the low gear ratio position and is returned to the normal gear ratio control.

Therefore, at the time of starting in the lock-up fixation failure state, after the engine stall is avoided by returning the gear shift spool of the gear shift control valve f to the reference position, when the vehicle speed at which the engine stall can be avoided is reached, the normal gear ratio is smoothly achieved. The control is restored, and traveling at the optimum gear ratio is secured.

The operation of the third invention will be described.

In detecting the starting time in the lock-up fixation failure state, the starting time control means j of the third invention is used.
Then, at the time of starting, when the speed change spool of the speed change control valve f is moved from the reference position to the low speed ratio position side and the vehicle speed detection value from the vehicle speed detection means k reaches the measurement error avoidance set value, detection is performed. The detected engine speed equivalent value is detected when it falls below the engine stalling allowable value.

Therefore, when the detected engine speed equivalent value is affected by a measurement error when starting from a stopped state, such as the turbine speed or speed ratio, measurement is performed in an extremely low speed state immediately after starting. It may be erroneously detected that the vehicle is starting in the lockup sticking failure state due to an error, but this erroneous detection is prevented by adding the vehicle speed condition that the vehicle speed detection value reaches the measurement error avoidance set value. can do.

The operation of the fourth invention will be described.

The stalling allowable value used by the starting control means j for determining the lockup sticking failure at the time of starting is larger as the throttle opening detection value from the throttle opening detection means n in the stalling allowable value setting means o is larger. Set to the value.

Therefore, for example, at the time of starting with a large accelerator operation amount, the engine speed equivalent value due to the lock-up sticking suddenly decreases, and it is necessary to take an early stall countermeasure. The larger the throttle opening detection value is set, the larger the value is set, so that it is detected that the lockup sticking failure is early in the period after the engine speed equivalent value starts to decrease, and the shift spool is returned to the reference position. As described above, the engine stall avoidance is surely achieved regardless of the accelerator operation amount at the time of starting.

[0027]

Embodiments of the present invention will be described below with reference to the drawings.

(First Embodiment) First, the structure will be described.

FIG. 2 is a control system system diagram to which the start control device of the toroidal continuously variable transmission of the first embodiment corresponding to the first and second inventions is applied, and FIG. 3 is the hydraulic control of the first embodiment device. It is a figure which shows the principal part of a circuit.

Reference numeral 10 in FIG. 2 shows a toroidal continuously variable transmission (corresponding to the continuously variable transmission d), in which the torque from an engine (not shown) is a torque converter 12 (corresponding to the fluid transmission device c).
Is input to the continuously variable transmission 10 via. The torque converter 12 includes a pump impeller 12a and a turbine runner 12
b, the stator 12c, the lock-up clutch 12d (corresponding to the lock-up mechanism b), the apply-side oil chamber 12e, the release-side oil chamber 12f, etc., and the input shaft 14 penetrates through the central portion thereof.

The input shaft 14 is connected to a forward / reverse switching mechanism 36, which has a planetary gear mechanism 42,
A forward clutch 44, a reverse brake 46, etc. are provided. The planetary gear mechanism 42 includes a ring gear 42b and a sun gear 42c that mesh with each of the double planetary gears.

The right end of the input shaft 14 is supported by the torque transmission shaft 16 arranged coaxially. In the present example, the first continuously variable transmission mechanism 1 is provided on the torque transmission shaft 16.
8 and the second continuously variable transmission mechanism 20 are arranged in tandem on the downstream side in the transmission case 22 (dual cavity type).
The body of the hydraulic control circuit 61 is arranged on the base indicated by reference numeral 64.

The first continuously variable transmission mechanism 18 has a pair of input disks 18a and output disks 18b whose opposing surfaces are formed in a toroidal curved surface and frictional contact between the opposing surfaces of these input / output disks and the torque transmission shaft 16. A pair of power rollers 18c and 18d are arranged symmetrically with respect to each other, a supporting mechanism for tiltably supporting these power rollers, and a servo piston as a hydraulic actuator. Second
Similarly, in the continuously variable transmission mechanism 20, the input / output disks 20a and 20b having opposing toroidal curved surfaces and the pair of power rollers 20 are provided.
c, 20d, its support mechanism, and a servo piston.

On the torque transmission shaft 16, the continuously variable transmission mechanisms 18 and 20 are arranged opposite to each other so that the output disks 18b and 20b face each other, and the input disk 18a of the first continuously variable transmission mechanism 18 is the torque converter 12. It is pressed toward the right side in the axial direction in the drawing by the loading cam device 34 that generates a pressing force according to the input torque that has passed. The device 34 has a loading cam 34 a and is supported by the shaft 16 via a thrust bearing 38. The input disk 20a of the second continuously variable transmission mechanism 20 is biased by the disc spring 40 toward the left side in the axial direction in the drawing.

The input disks 18a, 20a are supported by the transmission shaft 16 via ball splines 24, 26 so as to be rotatable and axially movable. In the above mechanism,
Each power roller is tilted so as to obtain a tilt angle according to the gear ratio, and the input rotation of the input disk is continuously and continuously changed and transmitted to the output disk.

The output discs 18b and 20b are spline-coupled to an output gear 28 which is relatively rotatably fitted on the torque transmission shaft 16, and the transmission torque is transmitted to the output shaft (counter shaft) 30 through the output gear 28. Gear 3 combined
0a, and these gears 28, 30a form a torque transmission mechanism 32. Further, a transmission mechanism 48 including a gear 52 provided on the output shaft 30, a gear 56 provided on the output shaft 50, and an idler gear 54 meshing with the gears 52 is provided, and the output shaft 50 uses the propeller shaft 60 as a transmission mechanism. Shall be connected.

The hydraulic control circuit 61 includes a lockup control hydraulic circuit 62 for hydraulically controlling lockup engagement and lockup release of the lockup clutch 12d, a shift control valve 63 for producing a gear ratio control pressure during traveling, and It has a step motor 65 (corresponding to the gear ratio control actuator g) that drives the speed change spool 154 of the speed change control valve 63 according to an external command, and a lockup solenoid 66 that drives according to an external command.

The step motor 65 and the lockup solenoid 66 are driven by a control command from the CVT controller 70. The CVT controller 70 includes a throttle opening sensor 71 and an engine rotation sensor 7
2, sensor signals and switch signals are input from the input shaft rotation sensor (turbine rotation sensor) 73, the output shaft rotation sensor (vehicle speed sensor) 74, the inhibitor switch 75, and the like.

The hydraulic control circuit 61 will be described in detail with reference to FIG.

The lockup control hydraulic circuit 62 includes a lockup control valve 67, a lockup control pressure oil passage 80 connected to the lockup control valve 67, and a torque converter pressure oil passage 8.
1, a lubricating oil passage 82, a pilot pressure oil passage 83, a release pressure oil passage 84, and an apply pressure oil passage 85. The lockup control valve controls the hydraulic pressure generated by the lockup solenoid 66 whose duty ratio is controlled. By supplying to a port at one end of 67 and controlling the spool position, lockup engagement / release including lockup that allows slippage is controlled.

The shift control valve 63 is a step motor 6
5, a speed change spool 154 driven in the axial direction via a pinion and a rack, a sleeve 156 connected to the speed change spool 154 via a pin 193, and an inner diameter portion of the sleeve 156 are fitted to each other. It has a spool 158 driven by a shift feedback mechanism of a servo device, a spring 160 for pushing the spool 158 leftward in FIG. 3, and a spring 161 inserted between the sleeve 156 and the spool 158. The pin 19
3 is fitted in an axially long slot 191 formed in the speed change spool 154, and a pin 195 is attached by a spring 195.
Pressing 3.

In FIG. 3, 166 is a port connected to the high side oil passage 88 of the servo cylinder, 534 is a port connected to the line pressure oil passage 87, and 168 is connected to the low side oil passage 89 of the servo cylinder. Ports 540 are pilot pressure ports, 551 is a port connected to the lockup control pressure oil passage 80, and 553 is a port connected to the lockup solenoid pressure oil passage 86.

A land 154a is provided on the speed change spool 154 of the speed change control valve 63.
This changes the connection state of the port 540, the port 551, and the port 553. That is, the port 540 is blocked and the port 551 and the port 553 are connected by the land 154a from the low gear ratio to the high gear ratio for realizing the gear ratio range used in the gear ratio control during traveling ( The gear shift spool 154 in FIG. 3 corresponds to the low gear ratio position and the high gear ratio position, and is in an intermediate position between both positions for maintaining the gear ratio). When stopped, the speed change spool 154 is pushed leftward in FIG. 3, and the loss stroke of the speed change spool 154 due to the elongated hole 191 blocks the port 553 and connects the port 540 and the port 551 by the land 154a (reference). Equivalent to the position).

Next, the operation will be described.

[CVT Control Operation Processing] CVT control operation processing performed by the CVT controller is shown in FIGS.
It will be described based on.

FIG. 4 is a flowchart showing the processing performed by the signal measuring unit, the control signal output unit and the shift control unit every 10 msec. In the signal measuring unit, the engine speed Ne, the output shaft speed No and the throttle opening TVO. Is measured.
The control signal output unit outputs the step motor step number STEP obtained in the process of FIG. The shift control unit performs shift control at the time of starting according to the processing of FIG.

Each step of the control signal output processing of FIG. 6 will be described.

At step 90, the initial position SPi (reference position or LOW position) of the step motor 65 is read. Hereinafter, the low gear ratio position will be referred to as the LOW position, and the high gear ratio position will be referred to as the Hi position.

In step 91, the conversion coefficient A for converting the gear ratio into the number of steps is read.

At step 92, the target gear ratio TR is read from the measured output shaft revolution number No, the throttle opening TVO and the map shown in FIG. 5, and the target step TSTEP is calculated from this target gear ratio TR.

In steps 93 to 95, the number of steps is increased for each step deviation SP until the actual step STPF reaches the target step TSTEP.

At step 96, the total output step number ST
EP is obtained by the sum of the actual step STPF that matches the target step TSTEP and the initial position SPi.

Each step of the shift control process at the time of starting in FIG. 7 will be described.

In step 100, the initial position SP
After i is read, it is determined whether the shift inhibition flag F1 = 1.

In step 101, when F1 ≠ 1, it is determined whether the output shaft speed (vehicle speed) No is No> 0 or the throttle opening TVO is TVO> TVOidle (throttle opening threshold) (starting). Equivalent to the time detection means h).

At step 102, the initial position SP
i is the value at which the gear ratio is in the LOW position up to MINTP 10
Increased at 0 PPS (100 pulses per second).

In step 103, the engine speed Ne
It is determined whether (the engine speed equivalent value) is smaller than the engine stall avoidance allowable threshold Neth.

At step 104, the initial position SP
i is reduced at 100 PPS to SPi = 0 (reference position), and the shift inhibition flag F1 is set to F1 = 1.

At step 105, the initial position SP
After i is set to the reference position, neither gear is changed.

The steps 102 to 105 are
It corresponds to the starting control means j.

In step 106, when F1 = 1, it is determined whether the output shaft rotation speed (vehicle speed) No is larger than the output shaft rotation threshold Noth.

In step 107, when NO is determined in step 101 or step 106, the initial position SPi is reduced by 100 PPS until SPi = 0 (reference position).

In step 108, Y in step 106
When it is determined to be ES, the initial position SPi is SPi =
Increased at 100PPS to MINTP (LOW position). Note that steps 106 and 108 correspond to the gear ratio control returning means m.

At step 109, the initial position SP
It is determined whether i is SPi = MINSTP.

At step 110, Y at step 109.
When it is determined to be ES, the shift control is ended.

[Shift control operation at the time of normal start of lock-up] At the normal start without lock-up sticking failure, step 100 →
The flow proceeds from step 101 → step 102 → step 103 → step 109 → step 110.

That is, when there is no lockup sticking failure, the port 540 and the port 551 are connected at the reference position of the speed change spool 154 at the time of stop, and the pilot pressure PP which is constantly generated is the lockup control pressure oil passage 8.
By being supplied to 0 and forcibly set to the lockup release state, the engine speed increases in response to the accelerator operation at the time of starting, and the engine stall condition of step 103 is not satisfied.

Therefore, the speed change spool 154 is moved from the reference position to the LOW position by the step motor 65, and the speed change spool 154 is prepared for the subsequent speed ratio control during traveling.

[Shift Control Operation at Lock-Up Sticking Start] The start-up operation at lock-up sticking failure will be described with reference to the flowchart of FIG. 7 and the time chart of FIG.

During the period shown in FIG. 8, the vehicle is in a stopped state and the lockup is fixed. The throttle is opened at point A and the vehicle is starting.

First, similarly to the above, the speed change spool 154 is moved from the reference position to the LOW position by the step motor 65.

In this LOW position, the lockup is not released, so the engine speed gradually decreases and the engine stall condition of step 103 is satisfied (FIG. 8).
B portion), the flow proceeds from step 103 to step 104 → step 105. In step 104, the speed change spool 154 is returned from the LOW position to the reference position again, and the speed change inhibition flag F1 is set to F1 = 1.

In this way, when the engine speed Ne becomes smaller than the engine stall avoidance allowable threshold Neth and it is detected that the vehicle is locked in the locked-up state at the time of starting, again,
Return the speed change spool 154 to the reference position and set the port 540
And the port 551 are connected to forcibly enter the lockup release state. As a result, the engine load is reduced and the engine speed Ne increases again.

When the output shaft rotation speed (vehicle speed) No becomes larger than the output shaft rotation threshold Noth at the time point C, the routine proceeds from step 106 to step 108, where the speed change spool 154 moves from the reference position to the LOW position. Then, the gear ratio control during traveling is prepared. That is, when the output shaft rotation (vehicle speed) does not stall, the start-up control at the lock-up sticking failure is stopped, and the control shifts to the normal gear ratio control.

[Lock-up control operation during traveling] The lock-up control during traveling is executed according to a preset lock-up schedule. That is, when the detected traveling state is in the lockup release area on the schedule, the lockup is released, and when the detected traveling state is in the lockup engagement area on the schedule, the lockup is engaged.

In this lock-up control, as shown in FIG. 3, the solenoid pressure generated by the lock-up solenoid 66 is guided to the lock-up control pressure oil passage 80 as it is,
This is performed by controlling the spool position of the lockup control valve 67. For example, in the lockup released state, the spool position of the lockup control valve 67 is set to the left side position in FIG. 3, and the torque converter pressure is changed to
By making the oil passage 81 → the oil passage 84 → the release side oil chamber 12f → the apply side oil chamber 12e → the oil passage 85 → the oil passage 82, the left and right oil chambers 12e and 12f of the lockup clutch 12d are made to have the same pressure. To be achieved.

For example, in the lock-up engaged state, the spool position of the lock-up control valve 67 is set to the right side position in FIG. 3, and the torque converter pressure is guided to the apply side oil chamber 12e through the oil passage 81 → the oil passage 85. , The hydraulic oil in the release side oil chamber 12f is drained after passing through the oil passage 84, and the left and right oil chambers 12 of the lockup clutch 12d are drained.
This is achieved by giving a differential pressure to e and 12f.

[Operation of the gear ratio during traveling] In the gear ratio control during traveling, the line pressure supplied from the oil passage 87 is used as the gear control pressure, and the sleeve 156 integral with the gear spool 154.
The line pressure is distributed to the oil passages 88 and 89 by the movement of
This is performed by changing the pressure difference between both oil passages and shifting the center of rotation of the power roller from the center of rotation of the input / output disk by the vertical movement of the piston (offset).

The tilt angle in this case is fed back to the spool 158 via a lever (not shown), and the spool 1
Reference numeral 58 follows the displacement of the sleeve 156 according to the gear ratio command of the speed change spool 154, and returns to the original relative position to this. As a result, the differential pressure between the oil passage 88 and the oil passage 89 is stabilized in a state where the designated gear ratio is maintained.

Thus, the gear shift control valve 63 basically performs feedback control so that the actual gear ratio becomes the target gear ratio, and when the power roller is in the tilted state corresponding to the gear ratio command, the offset is set to 0. The specified gear ratio is maintained.

Next, the effect will be described.

(1) In a start control device for a toroidal continuously variable transmission provided with a torque converter 12 having a lockup clutch 12d, the lockup clutch 12d is at a position where a low gear ratio is commanded and regardless of other conditions. Shift control valve 63 having a reference position on the shift spool 154 for forcibly releasing the
While the shift spool 154 of the shift control valve 63 is moved from the reference position to the LOW position or after the shift spool 154 is moved, the detected engine speed Ne is equal to the engine allowable threshold Ne.
When it becomes smaller than th, the device for performing the starting control that outputs the command to return the speed change spool 154 from the LOW position to the reference position to the step motor 65 is used as the device for the start ratio control in the lock-up sticking failure state. Engine stall avoidance can be achieved without creating a lock-up impossible area in the gear ratio area used.

(2) The shift spool 15 is controlled by the starting control.
When the output shaft speed No. reaches the engine stall avoidance threshold Noth in the state where 4 is returned to the reference position, the shift spool 15
4 is a device for returning the gear ratio control from the reference position to the LOW position and returning to the normal gear ratio control.
After starting the vehicle, it is possible to smoothly return to the gear ratio control during traveling.

(Second Embodiment) A start control system for a toroidal continuously variable transmission according to a second embodiment corresponding to the first, second, third and fourth inventions will be described.

The hardware structure of the device of the second embodiment is similar to that of the device of the first embodiment shown in FIGS. 2 and 3, so that illustration and description thereof will be omitted.

Next, the operation will be described.

[CVT Control Operation Processing] CVT control operation processing performed by the CVT controller will be described with reference to FIGS. 9 to 1.
It will be described based on 3.

FIG. 9 is a flow chart showing the processing performed by the signal measuring unit and the signal output unit every 10 msec.

In step 200, the throttle opening TV
O, engine speed Ne, input shaft speed Nt, output shaft speed No, and inhibitor signal are measured.

In step 201, the vehicle speed Vsp is calculated from the output shaft speed No and the coefficient A, and the speed ratio e is calculated from the engine speed Ne and the input shaft speed Nt. For example, as shown in FIG. Based on the map and the throttle opening TVO, the speed ratio threshold eth and the input shaft rotation speed threshold Nt
The th and the engine speed threshold Neth are read.

In step 202, the step motor output step number ASTEP obtained in the processing of FIG. 12 is output.

FIG. 11 is a flowchart showing the flow of the shift control processing operation performed by the shift control unit every 10 msec. Each step will be described below.

At step 210, forward / backward movement is judged by the inhibitor signal.

At step 211, other gear shift control such as neutral control is performed when the vehicle is not traveling forward or backward (corresponding to the starting detecting means h).

At step 212, it is judged if the vehicle speed Vsp exceeds the set vehicle speed Vsth2 at which there is no fear of engine stall.

In step 213, the target input shaft speed TNt is read from the shift map shown in FIG. 5, and this is divided by the vehicle speed Vsp to obtain the target speed ratio RRTO. Further, the step number FSTP is read from the target gear ratio RRTO by referring to the step map shown in FIG. 10B, and this is set as the target step number DSRSTP. Then, the change step value DSTP is set to 1.

At step 214, the target number of steps DS
Step motor control is performed to obtain RSTP.

The steps 212 to 214 are
It corresponds to the gear ratio control returning means m.

In step 215, it is determined whether or not the lock-up sticking fail flag F1 is F1 = 1, that is, whether or not the fail has been made so far.

In step 216, when F1 = 0,
It is determined whether engine speed Ne is less than engine speed threshold Neth.

In step 217, when Ne ≧ Neth, it is determined whether or not the vehicle speed exceeds the set vehicle speed Vsth1 with no measurement error.

In step 218, it is determined whether the speed ratio e (engine rotation speed equivalent value) exceeds the speed ratio threshold eth, or the input rotation speed Nt (engine rotation speed equivalent value) is input rotation threshold Ntth. Is exceeded.

In step 219, when YES is determined in step 216 or step 218, the lockup sticking fail flag F1 is set to F1 = 1.

At step 220, the target number of steps DS
RSTP is set to DSRSTP = 0 and change step value DS
Let TP be 10.

In step 221, the step motor 65 is driven and controlled by the target step number DSRSTP and the change step value DSTP set in step 220, and the shift spool 154 of the shift control valve 63 is returned to the reference position.

The steps 216 to 221 are
It corresponds to the starting control means j.

FIG. 12 is a flowchart showing the flow of the step motor control processing operation performed by the step motor control unit every 10 msec. Each step will be described below.

At step 230, it is judged if the step motor output step number ASTP exceeds the step number LOWSTP from the reference position of the speed change spool 154 to the LOW position.

At step 231, ASTP≤LOWS.
When it is TP, the change step value DSTP is DSTP
= 10. That is, the step motor 65 is operated at high speed.

At step 232, ASTP> LOWS
When TP, the step motor output step number AS
It is determined whether TP exceeds the target number of steps DSRSTP.

At step 233, the previous step motor output step number ASTP is changed to the step value DSTP.
The value obtained by adding (= 1) is set as the current step motor output step number ASTP.

At step 234, it is judged if the step motor output step number ASTP exceeds the target step number DSRSTP.

At step 235, ASTP> DSRS
When TP, step motor output step number ASTP
Is the target step number DSRSTP.

At step 236, the previous step motor output step number ASTP is changed to the step value DSTP.
The value obtained by subtracting (= 1) is the current step motor output step number ASTP.

At step 237, it is judged if the step motor output step number ASTP is less than the target step number DSRSTP.

As the target step number DSRSTP,
For example, when the maximum value 100 is given, as shown in FIG. 13, the step motor output step number ASTP approaches the target step number DSRSTP at the speed set by the change step value DSTP.

[Shift control operation at the time of normal start of lock-up] At the normal start without lock-up sticking failure, step 210 in the flowchart of FIG.
→ Step 212 → Step 215 → Step 216 →
The flow proceeds from step 217 → step 218 → step 213 → step 214.

That is, when there is no lockup sticking failure, the port 540 and the port 551 are connected at the reference position of the speed change spool 154 at the time of stop, and the pilot pressure PP which is constantly generated is the lockup control pressure oil passage 8.
By being supplied to 0 and forcibly set to the lockup release state, the engine speed increases according to the accelerator operation at the time of starting, the engine stall condition of step 216 is not satisfied, and the speed ratio condition of step 218 is not satisfied. Alternatively, the input shaft speed condition is not satisfied.

Therefore, the speed change spool 154 is moved from the reference position to the target input shaft rotation speed TNt by the step motor 65.
Is moved to the position where is obtained.

[Shift Control Operation at Lock-Up Sticking Start] The start-up operation at lock-up sticking failure will be described with reference to the flowchart of FIG. 11 and the time chart of FIG.

First, when the N range is selected to the D range or the R range, the throttle is opened and the vehicle is started, the speed change spool 154 is moved from the reference position to the LOW position by the step motor 65, and the target input shaft speed TNt is changed from the LOW position. It is moved in the direction in which it can be obtained.

In this state, the lockup solenoid 6
Since the lockup is not released due to a failure of the lockup control valve 67 or the lockup control valve 67, the engine speed gradually decreases.

Therefore, if the engine stall condition of step 216 is satisfied first, steps 216 to 219 →
The flow proceeds from step 220 to step 221,
In step 221, the speed change spool 154 is returned from the vicinity of the LOW position to the reference position again at high speed. In addition, before the engine stall condition of step 216 is satisfied, step 2
When the speed ratio condition of 18 or the input shaft speed condition is satisfied, the flow proceeds from step 218 to step 219 → step 220 → step 221. In step 221, the speed change spool 154 returns from the vicinity of the LOW position to the reference position again. Is returned at high speed. When the flag of F1 is set in step 219, the process of step 210 → step 212 → step 215 → step 220 → step 221 is repeated, and the reference position setting of the speed change spool 154 is maintained.

In this way, when the engine speed Ne becomes smaller than the threshold value Neth and it is detected that the lockup is fixed at the start, or Vsp> V
When it is detected that the lockup is fixed at the time of starting due to the speed ratio e becoming larger than the threshold value eth or the input shaft speed Nt becoming smaller than the threshold value Ntth under the condition of sth1, the speed change spool is restarted. 154 is returned to the reference position, the port 540 and the port 551 are connected, and the lockup release state is forcibly made. As a result, the engine load is reduced and the engine speed Ne increases again.

When the vehicle speed Vsp becomes higher than the set value Vsth2 while the reference position setting of the speed change spool 154 is maintained, the process proceeds from step 212 to step 213 → step 214 to move the speed change spool 154 from the reference position to the LOW position. To the target input shaft speed TNt, and then the gear ratio control is performed to obtain the target input shaft speed TNt. That is,
When the vehicle speed Vsp at which the engine is not stalled is reached, the start-up control is stopped at the time of lock-up sticking failure, and shifts to normal gear ratio control.

[Influence of rotation measurement error] The rotation sensor 7
The rotation measurement signals from 2, 73 and 74 include a measurement error when starting from a stopped state.

In particular, as shown in FIG. 15, the input shaft rotation speed Nt exhibits a measurement signal characteristic that it immediately increases immediately after starting, then decreases and then increases again.

Therefore, the input shaft rotation speed N immediately after starting the vehicle
The value of the speed ratio e calculated using t and the input shaft rotation speed Nt has a large error effect. For example, even when the lockup sticking failure is not occurred, the lockup sticking exceeds the determination threshold value and lockup sticking occurs. There is a concern that it may be erroneously detected that the vehicle is starting at a failure.

Therefore, when the vehicle speed Vsp is higher than the set vehicle speed Vsth (step 217) except immediately after starting the vehicle, the speed ratio condition and the input shaft rotational speed condition are judged, so that there is no influence of the rotation measurement error. Highly accurate lockup sticking failure detection is performed.
When the engine speed Ne is detected, the influence of the rotation measurement error is irrelevant.

[Setting of lockup determination threshold value]
In the second embodiment, based on the map shown in FIG. 10A and the throttle opening TVO, the speed ratio threshold eth, the input shaft revolution speed threshold Ntth, and the engine revolution speed threshold Ne.
th and are set. That is, as the throttle opening TVO is larger, the speed ratio threshold value eth is closer to 0, the input shaft speed threshold value Ntth is higher, and the engine speed threshold value Neth is higher. .

Therefore, for example, when the vehicle is started with a large accelerator operation amount, the detected values e, N due to the lockup sticking
It is necessary to take measures against engine stalling at an early stage due to the sudden decrease in t and Ne. On the other hand, the threshold values eth, Ntth, N
The larger eth is, the larger the throttle opening TVO is (e
By setting th to a value close to 0), each detected value e, N
It is detected that the lock-up sticking failure is early in the period from the beginning of the decrease of t and Ne, and the speed change spool 154 is returned to the reference position.

By thus setting the respective threshold values eth, Ntth, and Neth in accordance with the throttle opening TVO,
Engine stall avoidance is achieved regardless of the accelerator operation amount when starting.

The lockup control operation during traveling and the control operation during shifting are the same as in the first embodiment.

Next, the effect will be described.

In the second embodiment device, the following effects are added to the effects (1) and (2) of the first embodiment device.

(3) At the time of starting, while the speed change spool 154 of the speed change control valve 63 is being moved from the reference position to the LOW position side, the speed ratio e is increased under the condition that the vehicle speed Vsp is higher than the set value Vsth1. When the input shaft rotation speed Nt becomes larger than the threshold value eth or becomes smaller than the threshold value Ntth, a device for outputting a command for returning the speed change spool 154 from the LOW position to the reference position to the step motor 65 is used. When the speed ratio e or the input shaft rotation speed Nt is used for, the detection accuracy of the lock-up fixation failure state at the time of starting can be improved.

(4) The respective threshold values eth, Ntth, and Neth used for the lock-up fixation failure determination are larger as the throttle opening TVO is larger (eth is a value closer to 0).
Since the device is set to, engine stall avoidance can be reliably achieved regardless of the accelerator operation amount at the time of starting.

Although the embodiments have been described above with reference to the drawings, the specific configuration is not limited to the embodiments, and modifications and additions within the scope not departing from the gist of the present invention are included in the present invention. Be done.

For example, in the embodiment, the example of application to the toroidal continuously variable transmission is shown, but the invention can also be applied to the V-belt type continuously variable transmission.

[0140]

According to the first invention of claim 1,
In a start control device for a continuously variable transmission provided with a hydraulic power transmission having a lockup mechanism, a standard for forcibly releasing the lockup mechanism regardless of other conditions at a position for commanding a low gear ratio The engine speed equivalent value detected while the shift control valve that has the position on the shift spool and the shift spool of the shift control valve when starting to move from the reference position to the low gear ratio position side is the allowable engine stall value. When it falls below, the device provided with the starting control means for outputting a command to the gear ratio control actuator to return the gear change spool from the low gear ratio position to the reference position. The effect that the engine stall avoidance can be achieved without creating the feasible area is obtained.

According to a second aspect of the present invention, in the starting control device for the continuously variable transmission according to the first aspect, the vehicle speed is controlled while the speed change spool is returned to the reference position by the starting control means. When the vehicle speed detection value from the detection means reaches the engine stall avoidance set value, the speed change spool is returned from the reference position to the low gear ratio position to return to the normal gear ratio control. In addition, it is possible to obtain an effect that a smooth return to the speed change ratio control during traveling can be achieved after the vehicle starts.

According to a third aspect of the present invention, in the starting control system for a continuously variable transmission according to the first or second aspect, the starting control means is used to change the speed of the shift control valve when starting. When the spool is moved from the reference position to the low gear ratio position and the vehicle speed detection value from the vehicle speed detection means reaches the measurement error avoidance set value, the detected engine speed equivalent value is equal to or less than the engine stall allowable value. If the value of the lock-up sticking failure state is decreased to 3, the output of the command to return the speed change spool from the low gear ratio position to the reference position is output to the gear ratio control actuator. The effect is obtained.

According to a fourth aspect of the present invention, in the start control device for a continuously variable transmission according to any one of the first to third aspects, the start control means determines the lockup sticking failure at the start. Since the engine stall allowable value setting means for setting the engine stall allowable value to be set to a larger value as the detected throttle opening degree from the throttle opening detecting means is larger, in addition to the above effect, regardless of the accelerator operation amount at the time of starting The effect that the engine stall avoidance can be certainly achieved is obtained.

[Brief description of drawings]

FIG. 1 is a claim correspondence diagram showing a start control device for a continuously variable transmission according to the present invention.

FIG. 2 is an overall system diagram showing a start control device for a toroidal continuously variable transmission according to a first embodiment.

FIG. 3 is a circuit diagram showing a main part of a hydraulic control circuit of the first embodiment device.

FIG. 4 is a flowchart showing processing in a signal measuring unit, a control signal output unit, and a shift control unit of the CVT controller of the first embodiment device.

FIG. 5 is a diagram showing a shift map used for shift control in the first embodiment apparatus or the second embodiment apparatus.

FIG. 6 is a flowchart showing the flow of a shift control operation during traveling in the first embodiment device.

FIG. 7 is a flowchart showing a flow of a shift control operation at start in the apparatus of the first embodiment.

FIG. 8 is a time chart showing a step motor drive characteristic, a rotation speed characteristic, and a throttle opening degree characteristic at the time of starting with a lockup sticking failure in the first embodiment device.

FIG. 9 is a flowchart showing processing in a signal measuring unit and a signal output unit of the CVT controller of the second embodiment device.

FIG. 10: Each characteristic of lock-up sticking fail threshold
It is a figure which shows (a) and a gear ratio-step number conversion characteristic (b).

FIG. 11 is a flowchart showing a flow of a shift control operation process performed by a shift control unit of the CVT controller of the second embodiment device.

FIG. 12 is a flowchart showing a flow of step motor control operation performed by a step motor control unit of the CVT controller of the second embodiment device.

FIG. 13 is a time chart showing the relationship between the target step number and the step motor output step number in the step motor control of the second embodiment device.

FIG. 14 is a time chart showing a select characteristic, a throttle characteristic, a speed ratio characteristic, a rotation speed characteristic, and a step motor drive characteristic at the time of starting with a lockup fixation failure in the second embodiment device.

FIG. 15 is a diagram showing a start control device for a continuously variable transmission at the time of starting with a lockup sticking failure in the second embodiment device.

FIG. 16 is a speed change spool position characteristic diagram showing an example in which the lock-up prohibition region is different depending on the hardware structure of the speed change spool.

FIG. 17 is a diagram showing a lock-up impossible area when the lock-up prohibited area is enlarged.

[Explanation of symbols]

 a engine b lock-up mechanism c fluid transmission device d continuously variable transmission e lock-up control hydraulic circuit f shift control valve g gear ratio control actuator h start-up detection means i engine speed equivalent value detection means j start-up control means k vehicle speed Detection means m Gear ratio control return means

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display area F16H 59:44

Claims (4)

[Claims] 1. A continuously variable transmission that is connected to an engine and is provided with a fluid transmission device having a lockup mechanism; and a lockup control hydraulic circuit that hydraulically controls lockup engagement and lockup release of the lockup mechanism. , The low gear ratio position and the high gear ratio position for realizing the gear ratio range used in the gear ratio control during traveling, and the position for commanding a low gear ratio, and the lock-up mechanism is forced regardless of other conditions. A shift control valve having a shift spool having a reference position for releasing the shift spool, a shift ratio control actuator for driving the shift spool in response to an external command, and a start-time detection means for detecting whether or not it is at the start. The engine speed equivalent value detection means for detecting the engine speed equivalent value and the speed change spool of the speed change control valve are changed from the reference position to low when starting. When the detected engine speed equivalent value falls below the engine stall allowable value while in the state of being moved to the speed ratio position side, a command for returning the speed change spool from the low speed ratio position to the reference position is issued to the speed ratio control actuator. A start control device for a continuously variable transmission, comprising: a start control means for outputting. 2. The start control device for a continuously variable transmission according to claim 1, wherein the vehicle speed detection value from the vehicle speed detection means is set to avoid engine stall with the speed change spool returned to the reference position by the start control means. A start control device for a continuously variable transmission, comprising: a gear ratio control returning means for returning the gear shift spool from a reference position to a low gear ratio position when the value is reached and returning to normal gear ratio control. 3. The start control device for a continuously variable transmission according to claim 1 or 2, wherein the start control means controls the shift spool of the shift control valve from a reference position to a low gear ratio position side at the start. When the vehicle speed detection value from the vehicle speed detection means reaches the measurement error avoidance setting value while the vehicle is moving, if the detected engine speed equivalent value falls below the allowable engine stall value, the transmission spool is moved to the low gear ratio position. A start control device for a continuously variable transmission, characterized in that it is a means for outputting from the gear ratio control actuator to a command to return to a reference position. 4. The start control device for a continuously variable transmission according to any one of claims 1 to 3, wherein the engine start allowable limit value used by the start control means to determine a lockup sticking failure at start is a throttle opening detection value. A start control device for a continuously variable transmission, comprising an engine stall allowable value setting means for setting a larger value as a detected throttle opening degree from the means is larger.