JP7278024B2 - gearbox controller - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device mounted on a vehicle together with a transmission capable of dividing power input to an input shaft (input shaft) into two systems and transmitting the power to an output shaft (output shaft).

Transmissions mounted on vehicles such as automobiles include a continuously variable transmission mechanism that continuously changes the power of the engine, a gear mechanism that transmits the engine power without going through the continuously variable transmission mechanism, and a continuously variable transmission mechanism. It has been proposed to include a planetary gear mechanism for combining the power from the engine and the power from the gear mechanism. In this transmission, the power from the engine can be split between the continuously variable transmission mechanism and the gear mechanism, and the split power can be synthesized by the planetary gear mechanism and transmitted to the wheels.

JP-A-2004-176890

The applicant has also proposed a transmission capable of transmitting the power of a drive source by dividing it into two systems as a power split type continuously variable transmission.

The proposed power split type continuously variable transmission includes a continuously variable transmission mechanism, a split transmission mechanism (parallel shaft gear mechanism) and a planetary gear mechanism. The continuously variable transmission mechanism has the same configuration as a known belt-type continuously variable transmission (CVT: Continuously Variable Transmission). The power of the engine input to the input shaft is transmitted to the primary shaft of the continuously variable transmission mechanism. A secondary shaft of the continuously variable transmission is connected to the sun gear of the planetary gear mechanism. The split transmission mechanism includes a split drive gear that transmits/disconnects the power of the input shaft, and a split driven gear that forms a gear train with the split drive gear and rotates integrally with the carrier of the planetary gear mechanism. An output shaft is connected to the ring gear of the planetary gear mechanism. Rotation of the output shaft is transmitted to the differential gear, and from the differential gear to the left and right drive wheels.

In this power split type continuously variable transmission, a belt mode and a split mode are provided as power transmission modes during forward running.

In the belt mode, the first clutch that connects/disconnects the sun gear and the ring gear of the planetary gear mechanism is engaged to connect the sun gear and the ring gear. In addition, the second clutch that switches transmission/interruption of power between the input shaft and the split drive gear is released, the split drive gear is put in a free rotation state (free), and the carrier of the planetary gear mechanism is in a free rotation state. be made. Therefore, the power output from the continuously variable transmission mechanism rotates the sun gear and the ring gear integrally, and the output shaft rotates integrally with the ring gear. Therefore, in the belt mode, as the gear ratio of the continuously variable transmission mechanism (belt gear ratio) increases, the gear ratio of the power split type continuously variable transmission (rotational speed of input shaft/output) increases in proportion to the belt gear ratio. The unit transmission ratio, which is the number of revolutions of the transmission shaft), increases.

In the split mode, the first clutch is released to disengage the sun gear and ring gear of the planetary gear mechanism. Therefore, the power output from the continuously variable transmission mechanism rotates the sun gear. On the other hand, when the second clutch is engaged, power is transmitted from the input shaft to the split drive gear, and the power is shifted from the split drive gear through the split driven gear at a constant split gear ratio, resulting in a planetary gear mechanism. entered into the carrier. Therefore, in the split mode, the larger the belt gear ratio, the smaller the unit gear ratio, and a gear ratio equal to or lower than the split gear ratio can be realized.

If the unit transmission ratio is changed across a split transmission ratio, the change in unit transmission ratio is accompanied by switching between belt mode and split mode. This mode switching is achieved by switching engagement between the first clutch and the second clutch (switching between the first clutch and the second clutch).

When the belt gear ratio and the split gear ratio are deviated from each other, differential rotation occurs between the sun gear and the carrier. Shift shock may occur. Therefore, in a state in which the belt gear ratio substantially matches the split gear ratio, the hydraulic pressure of the engaging side second clutch or the first clutch is increased while the hydraulic pressure of the disengaging side first clutch or the second clutch is reduced. , the engagement between the first clutch and the second clutch is switched.

However, due to various factors such as variations in rise of hydraulic pressure, engagement of the first clutch and the second clutch may be switched in a state where there is a deviation between the belt gear ratio and the split gear ratio.

This problem is not limited to the power split type continuously variable transmission proposed by the applicant, but it is necessary to switch between the first mode and the second mode in which the power transmission paths between the input shaft and the output shaft are different from each other. This is a problem common to transmissions that can be operated with the gear ratio in the first mode and the gear ratio in the second mode matching.

SUMMARY OF THE INVENTION An object of the present invention is a transmission control device capable of suppressing switching between a first mode and a second mode in a state where the gear ratio in the first mode and the gear ratio in the second mode are deviated from each other. is to provide

In order to achieve the above object, a transmission control device according to the present invention includes an input shaft, an output shaft, a continuously variable transmission mechanism for steplessly shifting power input to the input shaft, and engagement/disengagement by hydraulic pressure. Engagement of the first engagement element and release of the second engagement element as a mode of transmitting power between the input shaft and the output shaft, including the first engagement element and the second engagement element that are released A first mode is configured by disengaging the first engaging element and engaging the second engaging element, thereby configuring a second mode having a different power transmission path from the first mode. In at least one of the above, when power is transmitted via a continuously variable transmission mechanism and the transmission gear ratio of the continuously variable transmission mechanism takes a specific value, the gear ratio of the power transmission path in the first mode and the power transmission in the second mode A control device for a transmission configured to match the gear ratio of a path, comprising gear shift control means for changing the gear ratio of a continuously variable transmission mechanism, engagement of a first engagement element, and engagement of a second engagement element. At the time of switching between engagement and engagement of the elements, the oil pressure of the second engagement element on the disengagement side or the first engagement element is increased according to the fact that the gear ratio in the first mode matches the gear ratio in the second mode. While maintaining the hydraulic pressure for maintaining the engagement of the second engagement element or the first engagement element on the release side, the hydraulic pressure of the first engagement element or the second engagement element on the engagement side is changed to the engagement side. and double clutch control means for outputting a command to raise the hydraulic pressure at which the first engagement element or the second engagement element of the clutch is engaged.

According to this configuration, the first mode is configured when the first engagement element is engaged and the second engagement element is released. On the other hand, the second mode is configured when the first engagement element is released and the second engagement element is engaged. In at least one of the first mode and the second mode, power is transmitted between the input shaft and the output shaft via the continuously variable transmission. Further, when the gear ratio of the continuously variable transmission mechanism takes a specific value, the gear ratio in the first mode and the gear ratio in the second mode match.

When switching the engagement between the first engagement element and the second engagement element, the gear ratio of the continuously variable transmission is changed toward a specific value. Then, when the gear ratio of the continuously variable transmission mechanism matches a specific value, double clutch control is performed to hold or release the engagement of the second engagement element or the first engagement element on the disengagement side. While maintaining the command value of the hydraulic pressure of the second/first engagement element on the release side at a command value corresponding to the hydraulic pressure at which the engagement of the second engagement element or the first engagement element on the release side is maintained, The command value for the hydraulic pressure of the first engagement element or the second engagement element on the engagement side is suddenly increased to the command value corresponding to the hydraulic pressure at which the first engagement element or the second engagement element on the engagement side engages. , the first engaging element or the second engaging element on the engaging side engages.

Due to such double clutch control, even if there is variation in the rise of the hydraulic pressure of the first engagement element and/or the second engagement element (response variation), the gear ratio of the continuously variable transmission mechanism can be maintained at a specific value. The engagement between the first engagement element and the second engagement element can be switched. Therefore, it is possible to suppress switching of the engagement between the first engagement element and the second engagement element in a state where the gear ratio of the continuously variable transmission mechanism deviates from a specific value. It is possible to suppress the occurrence of shift shock due to the switching in a state in which is deviated from a specific value. Further, during double clutch control, the sum of the transmission torque capacity of the first engagement element and the transmission torque capacity of the second engagement element far exceeds the engine torque, so that the first engagement element and the second engagement element It is possible to suppress engine racing without learning the oil pressure response variation.

Furthermore, since the hydraulic pressure command value for the first engagement element or the second engagement element on the engagement side is increased at once, the time required to engage the first engagement element or the second engagement element on the engagement side can be shortened, and the time required for switching the engagement between the first engagement element and the second engagement element (shift time) can be shortened.

The control device prepares to supply hydraulic pressure to the first engagement element or the second engagement element on the engagement side while the gear ratio of the continuously variable transmission mechanism is changed toward a specific value by the gear shift control means. The configuration may further include preparation control means for performing control.

While the gear ratio of the continuously variable transmission mechanism is being changed toward a specific value, preparatory control is performed to supply hydraulic pressure to the first engagement element or the second engagement element on the engagement side. As a result, the clutch piston of the first engagement element or the second engagement element on the engagement side is in contact with the clutch plate without being pressed, that is, the first engagement element or the second engagement element on the engagement side. becomes jam-packed.

The transmission includes a sun gear that rotates integrally with the secondary pulley of the continuously variable transmission mechanism, a ring gear that rotates integrally with the output shaft, and a planetary gear mechanism including a carrier to which power is transmitted from the split transmission mechanism. , the first engagement element is hydraulically engaged/disengaged to couple/separate the sun gear and the ring gear so as to rotate integrally, and the second engagement element is for transmission/interruption of power to the carrier by the split transmission mechanism. may be hydraulically engaged/disengaged to switch between

With this configuration, when the first engagement element is released and the second engagement element is engaged, the larger the belt gear ratio, the smaller the unit gear ratio. constant gear ratio) or less. Therefore, in the transmission, by switching the engagement state of the first/second engagement elements (swapping the first/second engagement elements), the gear ratio width of the entire transmission can be changed steplessly. It is possible to secure a gear ratio width larger than that of the transmission mechanism alone.

According to the present invention, switching of engagement between the first engagement element and the second engagement element is suppressed in a state where the gear ratio in the first mode and the gear ratio in the second mode are deviated. It is possible to suppress the occurrence of shift shock due to the switching. Moreover, the time required for switching the engagement between the first engagement element and the second engagement element, that is, the time required for switching between the first mode and the second mode can be shortened.

1 is a skeleton diagram showing the configuration of a drive train including a power split type continuously variable transmission; FIG. It is a figure which shows the state of each engagement element with which a power split type continuously variable transmission is equipped. FIG. 3 is a collinear diagram showing the relationship between the number of revolutions (rotational speed) of the sun gear, carrier, and ring gear of the planetary gear mechanism provided in the power split type continuously variable transmission; 2 is a diagram showing a relationship between a gear ratio (belt gear ratio) of a continuously variable transmission provided in a power split type continuously variable transmission and a gear ratio (unit gear ratio) of the entire power split type continuously variable transmission; FIG. It is a figure which shows the structure of the control system which concerns on one Embodiment of this invention. FIG. 5 is a diagram showing temporal changes in clutch pressure (command value) during mode switching; It is a figure which shows the relationship between the power transmission state of a continuously variable transmission mechanism, a belt gear ratio, and a thrust ratio. FIG. 9 is a diagram showing another example of temporal change in clutch pressure (command value) during mode switching; FIG. 9 is a diagram for explaining a modification of the clutch pressure (command value) on the engagement side at the time of mode switching; FIG. 11 is a diagram for explaining a modification of the disengagement-side clutch pressure (command value) at the time of mode switching; FIG. 11 is a diagram for explaining another modified example of the clutch pressure (command value) on the disengagement side at the time of mode switching; FIG. 11 is a diagram for explaining still another modified example of the release-side clutch pressure (command value) at the time of mode switching; FIG. 11 is a diagram for explaining a fourth modification of the disengagement-side clutch pressure (command value) at the time of mode switching;

BEST MODE FOR CARRYING OUT THE INVENTION Below, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

<Vehicle drive system>
FIG. 1 is a skeleton diagram showing the configuration of the driving system of the vehicle 1. As shown in FIG.

A vehicle 1 is an automobile having an engine 2 as a drive source.

The engine 2 is provided with an electronic throttle valve for adjusting the amount of intake air into the combustion chamber of the engine 2, an injector (fuel injection device) for injecting fuel into the intake air, and a spark plug for generating electrical discharge in the combustion chamber. It is The engine 2 is also provided with a starter for starting the engine. The power of engine 2 is transmitted to differential gear 5 via torque converter 3 and power split type continuously variable transmission 4, and from differential gear 5 via drive shafts 6L and 6R to drive wheels (for example, left and right front wheels or rear wheels).

The engine 2 has an E/G output shaft 11 . The E/G output shaft 11 is rotated by power generated by the engine 2 .

The torque converter 3 has a pump impeller 21 , a turbine runner 22 and a lockup clutch (lockup mechanism) 23 . The E/G output shaft 11 is connected to the pump impeller 21 , and the pump impeller 21 and the E/G output shaft 11 are integrally rotatable about the same rotational axis. The turbine runner 22 is rotatably provided around the same rotational axis as the pump impeller 21 . The lockup clutch 23 is provided to directly connect/separate the pump impeller 21 and the turbine runner 22 . When the lockup clutch 23 is engaged, the pump impeller 21 and the turbine runner 22 are directly connected, and when the lockup clutch 23 is released, the pump impeller 21 and the turbine runner 22 are separated.

When the E/G output shaft 11 is rotated while the lockup clutch 23 is released, the pump impeller 21 rotates. Rotation of the pump impeller 21 causes a flow of oil from the pump impeller 21 toward the turbine runner 22 . This oil flow is received by the turbine runner 22 to rotate the turbine runner 22 . At this time, an amplifying action of the torque converter 3 occurs, and a power larger than the power (torque) of the E/G output shaft 11 is generated in the turbine runner 22 .

With the lockup clutch 23 engaged, when the E/G output shaft 11 is rotated, the E/G output shaft 11, the pump impeller 21 and the turbine runner 22 rotate together.

The power split type continuously variable transmission 4 includes an input shaft 31 , an output shaft 32 , a continuously variable transmission mechanism 33 , a reverse gear mechanism 34 , a planetary gear mechanism 35 and a split transmission mechanism 36 .

The input shaft 31 is connected to the turbine runner 22 of the torque converter 3 and integrally rotatable about the same rotational axis as the turbine runner 22 .

The output shaft 32 is provided parallel to the input shaft 31 . An output gear 37 is supported on the output shaft 32 so as not to rotate relative to it. The output gear 37 meshes with the differential gear 5 (ring gear of the differential gear 5).

The continuously variable transmission mechanism 33 has the same configuration as a known belt-type continuously variable transmission (CVT: Continuously Variable Transmission). Specifically, the continuously variable transmission mechanism 33 includes a primary shaft 41 , a secondary shaft 42 provided parallel to the primary shaft 41 , a primary pulley 43 supported by the primary shaft 41 so as not to rotate relative to the primary shaft 41 , and a secondary shaft 42 . and a belt 45 wound around the primary pulley 43 and the secondary pulley 44 .

The primary pulley 43 is arranged to face a fixed sheave 51 fixed to the primary shaft 41 with a belt 45 interposed therebetween. (primary sheave) 52. A cylinder 53 fixed to the primary shaft 41 is provided on the opposite side of the movable sheave 52 from the fixed sheave 51 , and a hydraulic chamber 54 is formed between the movable sheave 52 and the cylinder 53 .

The secondary pulley 44 is opposed to a fixed sheave 55 fixed to the secondary shaft 42 with the belt 45 interposed therebetween. (secondary sheave) 56; A cylinder 57 fixed to the secondary shaft 42 is provided on the opposite side of the movable sheave 56 from the fixed sheave 55 , and a hydraulic chamber 58 is formed between the movable sheave 56 and the cylinder 57 . In the rotation axis direction, the positional relationship between the fixed sheave 55 and the movable sheave 56 is reversed from the positional relationship between the fixed sheave 51 and the movable sheave 52 of the primary pulley 43 .

In the continuously variable transmission mechanism 33, the hydraulic pressure supplied to the hydraulic chambers 54, 58 of the primary pulley 43 and the secondary pulley 44 is controlled to change the groove widths of the primary pulley 43 and the secondary pulley 44. A pulley ratio between the pulley 43 and the secondary pulley 44 is continuously and steplessly changed.

Specifically, when the pulley ratio is decreased, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is increased. As a result, the movable sheave 52 of the primary pulley 43 moves toward the fixed sheave 51, and the gap (groove width) between the fixed sheave 51 and the movable sheave 52 is reduced. Accordingly, the winding diameter of the belt 45 around the primary pulley 43 increases, and the interval (groove width) between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 increases. As a result, the pulley ratio between the primary pulley 43 and the secondary pulley 44 becomes smaller.

When the pulley ratio is increased, the hydraulic pressure supplied to the hydraulic chamber 54 of the primary pulley 43 is decreased. As a result, the thrust ratio, which is the ratio of the thrust (primary thrust) of the primary pulley 43 to the thrust (secondary thrust) of the secondary pulley 44, decreases, and the distance between the fixed sheave 55 and the movable sheave 56 of the secondary pulley 44 decreases. , the distance between the fixed sheave 51 and the movable sheave 52 increases. As a result, the pulley ratio between the primary pulley 43 and the secondary pulley 44 increases.

On the other hand, the thrust of primary pulley 43 and secondary pulley 44 needs to be large enough to prevent slippage between primary pulley 43 and secondary pulley 44 and belt 45 . Therefore, the hydraulic pressure supplied to the hydraulic chamber 58 of the secondary pulley 44 is controlled so that a thrust corresponding to the magnitude of the torque input to the input shaft 31 is obtained.

The reverse gear mechanism 34 reverses and decelerates the power input to the input shaft 31 and transmits it to the primary shaft 41 . Specifically, the reverse gear mechanism 34 includes an input shaft gear 61 supported by the input shaft 31 so as not to relatively rotate, and a gear having a larger diameter and a larger number of teeth than the input shaft gear 61. It includes a primary shaft gear 62 that is non-rotatably supported and meshes with the input shaft gear 61 .

The planetary gear mechanism 35 has a sun gear 71 , a carrier 72 and a ring gear 73 . The sun gear 71 is spline-fitted to the secondary shaft 42 so as to be non-rotatable relative to the secondary shaft 42 . The carrier 72 is fitted onto the output shaft 32 so as to be relatively rotatable. Carrier 72 rotatably supports a plurality of pinion gears 74 . A plurality of pinion gears 74 are arranged on the circumference and mesh with the sun gear 71 . The ring gear 73 has an annular shape that collectively surrounds the plurality of pinion gears 74 , and meshes with each pinion gear 74 from the outside in the rotation radial direction of the secondary shaft 42 . The output shaft 32 is connected to the ring gear 73 , and the ring gear 73 is integrally rotatable about the same rotational axis as the output shaft 32 .

Split transmission mechanism 36 includes a split drive gear 81 and a split driven gear 82 meshing with split drive gear 81 .

The split drive gear 81 is fitted on the input shaft 31 so as to be relatively rotatable.

The split driven gear 82 is integrally rotatable around the same rotational axis as the carrier 72 of the planetary gear mechanism 35 . The split driven gear 82 is formed with a smaller diameter than the split drive gear 81 and has fewer teeth than the split drive gear 81 .

The power split type continuously variable transmission 4 also includes clutches C1 and C2 and a brake B1.

The clutch C1 is switched between an engaged state in which the input shaft 31 and the split drive gear 81 are directly connected (rotatably coupled together) and a released state in which the direct connection is released.

The clutch C2 is switched between an engaged state in which the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly connected (connected so as to rotate integrally), and a released state in which the direct connection is released.

The brake B1 is switched between an engaged state for braking the carrier 72 of the planetary gear mechanism 35 and a released state for allowing the carrier 72 to rotate.

<Speed change mode>
FIG. 2 shows the states of the clutches C1, C2 and the brake B1 when the vehicle 1 is traveling forward and backward. FIG. 3 is a collinear diagram showing the relationship between the number of rotations (rotational speed) of the sun gear 71, the carrier 72 and the ring gear 73 of the planetary gear mechanism 35. As shown in FIG. FIG. 4 shows the belt speed ratio, which is the speed ratio of the continuously variable transmission mechanism 33, and the unit speed ratio, which is the speed ratio of the power split type continuously variable transmission 4 as a whole, that is, the rotation of the input shaft 31 and the output shaft 32. It is a figure which shows the relationship with the unit gear ratio which is a numerical ratio.

In FIG. 2, "o" indicates that the clutches C1, C2 and the brake B1 are engaged. "X" indicates that the clutches C1, C2 and the brake B1 are released.

The power split type continuously variable transmission 4 has a belt mode and a split mode as transmission modes when the vehicle 1 moves forward. The belt mode and the split mode are switched by switching between a state in which the clutch C1 is engaged and a state in which the clutch C2 is engaged (replacement of the clutches C1 and C2).

In belt mode, clutch C1 and brake B1 are disengaged and clutch C2 is engaged, as shown in FIG. As a result, the split drive gear 81 is disconnected from the input shaft 31, the carrier 72 of the planetary gear mechanism 35 becomes free (free rotation state), and the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly connected.

The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 and transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33 to rotate the primary shaft 41 and the primary pulley 43 . Rotation of the primary pulley 43 is transmitted to the secondary pulley 44 via the belt 45 to rotate the secondary pulley 44 and the secondary shaft 42 . Since the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are directly connected, the sun gear 71 , the ring gear 73 and the output shaft 32 rotate integrally with the secondary shaft 42 . Therefore, in the belt mode, as shown in FIGS. 3 and 4, the unit speed ratio is the belt speed ratio (the pulley ratio between the primary pulley 43 and the secondary pulley 44 of the continuously variable transmission mechanism 33) and the front speed reduction ratio (the input shaft). 31 rotation speed/the rotation speed of the primary shaft 41).

In split mode, clutch C1 is engaged and clutch C2 and brake B1 are disengaged, as shown in FIG. As a result, the input shaft 31 and the split drive gear 81 are directly connected, and the rotation of the input shaft 31 can be transmitted to the carrier 72 of the planetary gear mechanism 35 via the split drive gear 81 and the split driven gear 82. The sun gear 71 of 35 and the ring gear 73 are separated.

The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 , transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33 , and transmitted from the primary shaft 41 through the primary pulley 43 , belt 45 and secondary pulley 44 . is transmitted to the secondary shaft 42 and then to the sun gear 71 of the planetary gear mechanism 35 . On the other hand, the power input to the input shaft 31 is accelerated and transmitted from the split drive gear 81 to the carrier 72 of the planetary gear mechanism 35 via the split driven gear 82 .

Since the gear ratio (split gear ratio) between the split drive gear 81 and the split driven gear 82 is constant and unchanged (fixed), in the split mode, if the power input to the input shaft 31 is constant, the planetary gear mechanism 35 , the rotation of the carrier 72 is held at a constant speed. Therefore, when the belt transmission ratio is increased, the number of rotations of the sun gear 71 of the planetary gear mechanism 35 decreases. rises. As a result, in the split mode, as shown in FIG. 4, the unit gear ratio of the power split type continuously variable transmission 4 decreases as the belt gear ratio of the continuously variable transmission mechanism 33 increases.

Rotation of the output shaft 32 in belt mode and split mode is transmitted to the differential gear 5 via the output gear 37 . As a result, the drive shafts 6L, 6R of the vehicle 1 rotate forward.

In the reverse mode when the vehicle 1 moves backward, the clutches C1 and C2 are released and the brake B1 is engaged, as shown in FIG. As a result, the split drive gear 81 is separated from the input shaft 31, the sun gear 71 and the ring gear 73 of the planetary gear mechanism 35 are separated, and the carrier 72 of the planetary gear mechanism 35 is braked.

The power input to the input shaft 31 is reversed and decelerated by the reverse gear mechanism 34 , transmitted to the primary shaft 41 of the continuously variable transmission mechanism 33 , and transmitted from the primary shaft 41 through the primary pulley 43 , belt 45 and secondary pulley 44 . is transmitted to the secondary shaft 42 and rotates the sun gear 71 of the planetary gear mechanism 35 integrally with the secondary shaft 42 . Since the carrier 72 of the planetary gear mechanism 35 is braked, the ring gear 73 of the planetary gear mechanism 35 rotates in the opposite direction to the sun gear 71 when the sun gear 71 rotates. The direction of rotation of the ring gear 73 is opposite to the direction of rotation of the ring gear 73 during forward movement (belt mode and split mode). The output shaft 32 rotates integrally with the ring gear 73 . Rotation of the output shaft 32 is transmitted to the differential gear 5 via the output gear 37 . As a result, the drive shafts 6L, 6R of the vehicle 1 rotate in the reverse direction.

<Vehicle control system>
FIG. 5 is a diagram showing the configuration of a control system according to one embodiment of the present invention.

The vehicle 1 is equipped with an ECU (Electronic Control Unit) including a microcomputer. A microcomputer contains, for example, a CPU, a ROM, a RAM, and a data flash (flash memory). In order to control each part of the vehicle 1, the vehicle 1 is equipped with a plurality of ECUs, and each ECU is connected so as to enable two-way communication by CAN (Controller Area Network) communication protocol. The multiple ECUs include an engine ECU 101 and a transmission ECU 102 .

An accelerator sensor 111 and an engine speed sensor 112 are connected to the engine ECU 101 .

The accelerator sensor 111 outputs a detection signal corresponding to the amount of operation of the accelerator pedal operated by the driver. Based on the detection signal input from the accelerator sensor 111, the engine ECU 101 sets the ratio of the operation amount to the maximum operation amount of the accelerator pedal, that is, when the accelerator pedal is not depressed to 0%, and when the accelerator pedal is fully depressed. The accelerator opening is calculated as a percentage with the time when the engine is closed as 100%.

The engine speed sensor 112 outputs a pulse signal synchronized with the rotation of the engine 2 (rotation of the crankshaft) as a detection signal. The engine ECU 101 converts the frequency of the pulse signal input from the engine speed sensor 112 into the speed of the engine 2 (engine speed).

The engine ECU 101 is provided in the engine 2 to start, stop, and adjust the output of the engine 2 based on information obtained from detection signals of various sensors and/or various information input from other ECUs. It controls electronic throttle valves, injectors and spark plugs.

The transmission ECU 102 is connected with a primary rotation speed sensor 113, a secondary rotation speed sensor 114, and the like.

Primary rotation speed sensor 113 outputs, for example, a pulse signal synchronized with the rotation of primary shaft 41 or primary pulley 43 of power split type continuously variable transmission 4 as a detection signal. Transmission ECU 102 converts the frequency of the pulse signal input from primary rotation speed sensor 113 into the primary rotation speed.

Secondary rotation speed sensor 114 outputs, for example, a pulse signal synchronized with the rotation of secondary shaft 42 or secondary pulley 44 of power split type continuously variable transmission 4 as a detection signal. Transmission ECU 102 converts the frequency of the pulse signal input from secondary rotation speed sensor 114 into a secondary rotation speed.

The transmission ECU 102 performs power split control for speed change control of the power split continuously variable transmission 4 based on information obtained from detection signals of various sensors and/or various information input from other ECUs. It controls various valves and the like for adjusting the hydraulic pressure supplied to each part of the continuously variable transmission 4 .

<Mode switching>
FIG. 6 is a timing chart for explaining the control performed when switching modes. FIG. 7 is a diagram showing the relationship between the power transmission state of the continuously variable transmission mechanism 33, the belt gear ratio, and the thrust ratio (balanced thrust ratio).

The unit gear ratio of the power split type continuously variable transmission 4 is changed by control of the belt gear ratio by the transmission ECU 102 . In controlling the belt gear ratio, first, a target rotation speed is set according to the accelerator opening and the vehicle speed based on the gear shift diagram. The shift map is a map that defines the relationship between the accelerator opening degree, vehicle speed, and target rotation speed, and is stored in the ROM of transmission ECU 102 . Information on the accelerator opening and the vehicle speed is input from the engine ECU 101 to the transmission ECU 102, for example. When the target rotation speed is set, a target gear ratio is obtained that makes the rotation speed input to the primary shaft 41 coincide with the target rotation speed.

Next, the secondary thrust required to prevent belt slippage in the continuously variable transmission mechanism 33 is set based on the target gear ratio and the input torque input to the continuously variable transmission mechanism 33 . The input torque is calculated by multiplying the torque ratio of the torque converter 3 by the engine torque. The engine torque is estimated, for example, from the accelerator opening and the engine speed by the engine ECU 101 and transmitted from the engine ECU 101 to the transmission ECU 102 . The torque ratio is a torque amplification factor corresponding to the speed ratio of the torque converter 3, and the speed ratio is a division value obtained by dividing the turbine speed by the engine speed.

Further, based on the relationship (map) shown in FIG. 7, a thrust ratio (=primary thrust/secondary thrust) is set according to the actual gear ratio and the input torque. Then, the primary thrust and the secondary thrust are set from the thrust ratio.

After that, from the set primary thrust and secondary thrust, the primary pressure, which is the hydraulic pressure that gives the primary thrust to the movable sheave 52 of the primary pulley 43, and the secondary pressure, which is the hydraulic pressure that gives the secondary thrust to the movable sheave 56 of the secondary pulley 44, are commanded. A value is set, and based on each command value, hydraulic pressure is supplied to the hydraulic chamber 54 of the primary pulley 43 and the hydraulic chamber 58 of the secondary pulley 44 so that the deviation between the target gear ratio and the actual gear ratio approaches zero. is controlled. The actual gear ratio is obtained by dividing the primary rotation speed by the secondary rotation speed.

When the unit gear ratio is changed across the split gear ratio (split point), the change of the unit gear ratio is accompanied by switching between the belt mode and the split mode (hereinafter simply referred to as "mode switching"). At the time of this mode switching, the transmission ECU 102 switches between a state in which the clutch C1 is engaged and a state in which the clutch C2 is engaged. be implemented.

When the belt gear ratio is being changed toward the split gear ratio, for example, when the belt gear ratio coincides with the split gear ratio after a certain amount of time has elapsed, preparatory control is performed (time T1).

In preparatory control for switching from the belt mode to the split mode, the command value for the hydraulic pressure of the clutch C2 is lowered to the command value corresponding to the first hydraulic pressure at which the engaged state of the clutch C2 is maintained, and the clutch C2 is engaged. The command value for the hydraulic pressure of the clutch C1 is increased from 0 to a command value corresponding to the second hydraulic pressure while maintaining the engaged state. The second hydraulic pressure is set, for example, to a hydraulic pressure such that the clutch piston of the clutch C1 is in contact with the clutch plate without being pressed, that is, the clutch C1 is in a tight state.

In the preparatory control for switching from the split mode to the belt mode, the command value for the hydraulic pressure of the clutch C1 is lowered to the command value corresponding to the first hydraulic pressure at which the clutch C1 is kept engaged, and the clutch C1 is engaged. The command value for the hydraulic pressure of the clutch C2 is increased from 0 to a command value corresponding to the second hydraulic pressure while maintaining the engaged state. The second hydraulic pressure is set, for example, to a hydraulic pressure such that the clutch piston of the clutch C2 is in contact with the clutch plate without being pressed, that is, the clutch C1 is in a tight state.

After that, double clutch control is performed in response to the fact that the belt gear ratio matches the split gear ratio (time T2).

In the double clutch control when switching from the belt mode to the split mode, the command value of the hydraulic pressure of the clutch C2 is held at the command value corresponding to the first hydraulic pressure, and the clutch C1 is operated while the clutch C2 remains engaged. The command value of the hydraulic pressure is increased at once from the command value corresponding to the second hydraulic pressure to the command value corresponding to the fully open pressure (maximum pressure). As a result, the clutch C1 is fully engaged while the clutch C2 remains engaged, resulting in a double clutch state in which both the clutches C1 and C2 are fully engaged. Then, when a certain period of time has passed since the belt gear ratio coincided with the split gear ratio, the command value for the hydraulic pressure of the clutch C2 is lowered to 0, and the clutch C2 is released (time T3).

In the double clutch control when switching from the split mode to the belt mode, the command value of the hydraulic pressure of the clutch C1 is held at the command value corresponding to the first hydraulic pressure, and the clutch C2 is operated while the clutch C1 remains engaged. The hydraulic pressure is increased at once from the command value corresponding to the second hydraulic pressure to the command value corresponding to the fully open pressure (maximum pressure). As a result, the clutch C2 is fully engaged while the clutch C1 remains engaged, resulting in a double clutch state in which both the clutches C1 and C2 are fully engaged. Then, when a certain period of time has passed since the belt gear ratio coincided with the split gear ratio, the command value for the hydraulic pressure of the clutch C1 is lowered to 0, and the clutch C1 is released (time T3).

<Effect>
As described above, during mode switching, the belt gear ratio, which is the gear ratio of the continuously variable transmission mechanism 33, is changed toward the split gear ratio. While the belt gear ratio is being changed toward the split gear ratio, preparatory control is performed to supply hydraulic pressure to the clutches C1 and C2 on the engagement side. As a result, the clutches C1 and C2 on the engagement side become loose. When the belt gear ratio coincides with the split gear ratio, double clutch control is performed, and the hydraulic pressures of the clutches C1 and C2 on the engagement side are raised while maintaining the hydraulic pressures of the clutches C1 and C2 on the disengagement side. As a result, the clutches C1 and C2 on the engagement side are engaged.

After the preparatory control, as shown in FIG. 8, the command values for the hydraulic pressures of the disengaging clutches C1 and C2 are swept down (gradually decreased at a constant rate of change over time) from the command values according to the first hydraulic pressure, and engaged. It is conceivable to carry out control to sweep up (gradually increase at a constant rate of change over time) the command value of the hydraulic pressure of the clutches C1 and C2 on the side from the command value corresponding to the second hydraulic pressure. However, in this control, even if the command value is set so that the total transmission torque capacity of the clutches C1 and C2 exceeds the engine torque, the engine 2 may rev up due to the influence of variations in response of the hydraulic pressures of the clutches C1 and C2. or a feeling of deceleration of the vehicle 1 may occur. Also, the shift time becomes longer.

Due to the double-clutch control, even if there is variation (response variation) in the rise of the hydraulic pressures of the clutches C1 and C2, the state in which the clutch C1 is engaged and the clutch C2 is engaged with the belt gear ratio matching the split gear ratio is achieved. The engaged state can be switched (the clutches C1 and C2 are switched). Therefore, it is possible to suppress switching between the state in which the clutch C1 is engaged and the state in which the clutch C2 is engaged while the belt speed ratio is deviated from the split speed ratio. It is possible to suppress the occurrence of shift shock due to the switching in a state deviated from the gear ratio. Also, during double clutch control, the sum of the transmission torque capacities of the clutches C1 and C2 far exceeds the engine torque, so that racing of the engine 2 is suppressed without learning variations in response of the hydraulic pressures of the clutches C1 and C2. can.

Furthermore, in the double clutch control, the hydraulic pressure command values for the clutches C1 and C2 on the engagement side are increased at once, so the time required for engagement of the clutches C1 and C2 on the engagement side can be shortened, and eventually the clutch C1 is engaged. It is possible to shorten the time (shift time) required for switching between the engaged state and the engaged state of the clutch C2 (replacement of the clutches C1 and C2).

In addition, preparatory control is performed before the double clutch control, and the clutches C1 and C2 on the engagement side are put in a tight state, so the time required for engagement of the clutches C1 and C2 on the engagement side is shortened. As a result, the time required for switching between the state in which the clutch C1 is engaged and the state in which the clutch C2 is engaged, that is, the time required for mode switching can be shortened.

<Modification>
Although one embodiment of the present invention has been described above, the present invention can also be implemented in other forms.

For example, in the above-described embodiment, the command value of the hydraulic pressure of the clutches C1 and C2 on the engagement side was raised from 0 to the command value corresponding to the second hydraulic pressure in the preparation control, but as shown in FIG. , the hydraulic pressure command values for the clutches C1 and C2 on the engagement side may remain zero. However, in the case of a configuration in which the command value of the oil pressure of the clutches C1, C2 on the engagement side is increased from 0 to the command value corresponding to the second oil pressure, the backlash elimination is completed before the clutches C1, C2 on the engagement side are engaged. Therefore, in the double clutch control, the engagement side clutches C1 and C2 can be engaged more quickly.

Further, as shown in FIG. 10, in the preparatory control, the command value of the hydraulic pressure of the clutches C1 and C2 on the release side is held at the command value corresponding to the full open pressure. , C2 may be held at a command value corresponding to the fully open pressure. However, in the configuration in which the command value of the hydraulic pressure of the clutches C1 and C2 on the release side is lowered to the command value according to the first hydraulic pressure in the preparation control, the command value of the hydraulic pressure of the clutches C1 and C2 on the release side is lowered to 0. After that (after time T3), the responsiveness of the clutches C1 and C2 on the release side is improved.

Furthermore, as shown in FIG. 11, in the preparation control, the command value of the hydraulic pressures of the clutches C1 and C2 on the releasing side is lowered to the command value corresponding to the first hydraulic pressure, and in the double clutch control, the clutch C1 on the releasing side is lowered. , C3 may be lowered to a command value corresponding to a third hydraulic pressure lower than the first hydraulic pressure. Further, as shown in FIG. 12, in the preparation control, the command value of the hydraulic pressure of the clutches C1, C2 on the release side is held at a command value corresponding to the fully opened pressure, and in the double clutch control, the command value of the clutches C1, C2 on the release side may be lowered to a command value corresponding to a third hydraulic pressure at which the engaged state of the clutches C1 and C2 on the disengagement side is maintained. With these configurations as well, compared to the configuration in which the command value of the hydraulic pressure of the clutches C1 and C2 on the release side is held at the command value corresponding to the full open pressure in the preparation control and the double clutch control, the clutches C1 and C2 on the release side is lowered to 0 (after time T3), the responsiveness of the clutches C1 and C2 on the releasing side can be improved.

In addition, the preparatory control is not an essential control. As shown in FIG. 13, the command values for the hydraulic pressures of the clutches C1 and C2 on the disengagement side are set for a certain period of time after the belt gear ratio coincides with the split gear ratio. At the point of time (time T3), the command value corresponding to the full open pressure may be lowered to 0 at once.

The sensors described above are merely examples of main sensors related to the present invention, and other sensors may be connected to engine ECU 101 and transmission ECU 102 .

Some or all of the functions of engine ECU 101 and transmission ECU 102 may be integrated into one ECU.

Further, in the above-described embodiment, as an example of the transmission according to the present invention, in either the belt mode or the split mode in which the power transmission paths between the input shaft 31 and the output shaft 32 are different from each other, A configuration in which power passes through the continuously variable transmission mechanism 33 is taken up. However, the present invention is not limited to the transmission having such a configuration, and the mode in which the power transmission path via the continuously variable transmission mechanism is configured and the power transmission path in which the power transmission path via the gear mechanism is configured without passing through the continuously variable transmission mechanism. It is also possible to apply it to a transmission having a configuration that has a mode that

Also, the power transmission path via the gear mechanism is not essential. The present invention can also be applied to a transmission configured to have a mode in which a power transmission path via a mechanism is configured. The belt mechanism in this case may have a fixed gear ratio or may have a variable gear ratio.

In addition, various design changes can be made to the above configuration within the scope of the matters described in the claims.

4: Power split type continuously variable transmission 31: Input shaft 32: Output shaft 33: Continuously variable transmission mechanism 36: Split transmission mechanism 43: Primary pulley 44: Secondary pulley 45: Belt 102: Transmission ECU (control device, transmission control means, double clutch control means)
C1, C2: Clutch (first engagement element, second engagement element)

Claims (1)

An input shaft, an output shaft, a continuously variable transmission mechanism for steplessly shifting the power input to the input shaft, and a first engagement element and a second engagement element that are engaged/released by hydraulic pressure,
As a mode for transmitting power between the input shaft and the output shaft, a first mode is configured by engaging the first engaging element and disengaging the second engaging element. A second mode having a power transmission path different from that of the first mode is configured by releasing the coupling element and engaging the second engagement element,
In at least one of the first mode and the second mode, when power is transmitted via the continuously variable transmission mechanism and the gear ratio of the continuously variable transmission mechanism takes a specific value, the transmission in the first mode A control device for a transmission configured so that the gear ratio and the gear ratio in the second mode match,
shift control means for changing the gear ratio of the continuously variable transmission mechanism;
While the gear ratio of the continuously variable transmission mechanism is changed toward the specific value by the gear shift control means, hydraulic pressure is supplied to the first engagement element or the second engagement element on the engagement side. preparation control means for performing preparation control for outputting a command;
After performing the preparation control by the preparation control means, when switching the engagement between the first engagement element and the second engagement element, the gear ratio in the first mode and the gear ratio in the second mode , the hydraulic pressure of the second engagement element or the first engagement element on the release side is maintained by the engagement of the second engagement element or the first engagement element on the release side. The hydraulic pressure of the first engagement element or the second engagement element on the engagement side is completely engaged by the first engagement element or the second engagement element on the engagement side. a double clutch control means for outputting a command to increase the full engagement oil pressure at once,
In the preparation control, the preparation control means reduces the hydraulic pressure of the second engagement element or the first engagement element on the release side from the full engagement hydraulic pressure to the second engagement element on the release side or the first engagement element on the release side. Outputting a command to lower the first hydraulic pressure that maintains the engaged state of the engaging element , and engaging the second engaging element or the first engaging element on the disengagement side in the engaged state. The hydraulic pressure of the first engagement element or the second engagement element on the engagement side is a second hydraulic pressure lower than the complete engagement hydraulic pressure, and the first engagement element or the second engagement element on the engagement side A control device that outputs a command to increase the second hydraulic pressure so that the clutch piston of the element is in contact with the clutch plate without being pressed .

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