JPH04113066A - Hydraulic control device of continuously variable transmission for vehicle - Google Patents

Abstract

PURPOSE:To hasten the return to a low speed ratio at the time of sudden stop and ensure the quickness at the time of restart by providing an input rotation switching valve, and a gear ratio switching valve, and regulating a regulator valve to have a high line pressure by the oil pressure of the gear ratio switching valve. CONSTITUTION:When the input rotating speed is less than a set speed and the transmission gear ratio is smaller than a set gear ratio, an oil pressure is guided to the port 51i of a regulator valve 50 by the action of a reverse inhibitor valve 110 and the spring receiver 55 of the regulator valve 50 to raise the line pressure. As the line pressure is guided to the oil chamber 27 of a driven side pulley, the thrust of the driven side pulley is raised and forcedly shifted down to a low speed ratio side. Consequently, at the point of time when a vehicle is stopped, the gear ratio is returned to and around the lowest speed ratio to allow the quick restart. To simplify the hydraulic circuit, the reverse inhibitor valve 110 is used jointly as an input rotation switching valve, and the spring receiver 55 of the regulator valve 50 is used jointly as a gear ratio switching valve, but respective exclusive valves may be also used.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a hydraulic control device for a continuously variable transmission for a vehicle, and particularly to a hydraulic control device for a continuously variable transmission for a vehicle equipped with a V-belt type continuously variable transmission. It is something.

[Conventional technology]

Conventionally, a vehicle transmission equipped with a V-belt type continuously variable transmission is known, for example, from Japanese Patent Laid-Open No. 58-42862. In the case of this continuously variable transmission, the engine output shaft is connected to the driving pulley via a fluid coupling, the driven pulley is connected to the axle, and the pressure in the oil chamber of the driven pulley is regulated with a pressure regulating valve. The line pressure is supplied to the oil chamber of the driving pulley by a speed change control valve.

The speed change control valve has one end in contact with the throttle cam,
Hydraulic pressure corresponding to the input rotational speed is led from the pitot tube to the other end, and line pressure is supplied according to the throttle opening and the input rotational speed. In addition, the pressure regulating valve has one end in contact with the gear ratio detection lever, and the other end receives hydraulic pressure from the pitot tube that corresponds to the input rotational speed. The line pressure is regulated accordingly.

[Problem to be solved by the invention]

In the case of a continuously variable transmission equipped with such a control valve, there is a possibility that the gear ratio of the held type continuously variable transmission will not return to the lowest speed ratio (Low). The pulley may stop at an intermediate ratio. Then, even if the vehicle attempts to restart from this state, there is a problem in that the driving force is insufficient and agile starting performance cannot be obtained.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hydraulic control system for a continuously variable transmission for a vehicle that can quickly return to a low speed ratio during a sudden stop and ensure agility when restarting.

[Means to solve the problem]

In order to achieve the above object, the present invention has an engine output shaft connected to a driving pulley of a V-held continuously variable transmission, a driven pulley connected to an axle, and a regulator valve that controls the discharge pressure of an oil pump. The line pressure is regulated according to the gear ratio and input rotational speed, and this line pressure is guided to the oil chamber of the driven pulley, and the transmission control valve drives the line pressure according to the throttle opening and input rotational speed. In a continuously variable transmission for vehicles in which oil is supplied to the oil chamber of a side pulley, an input rotation switching valve that opens an oil path from a hydraulic pressure source to an output port when the input rotation speed is below a set speed, and an input rotation switching valve. is input, and when the gear ratio is smaller than the set gear ratio, a gear ratio switching valve is provided which directs the output oil pressure to the regulator valve as a signal pressure, and the regulator valve increases the line pressure by the oil pressure of the gear ratio switching valve. It is designed to regulate the pressure.

[Effect]

If you apply a sudden brake while driving at a high speed ratio, the input rotation speed will drop below the set speed, so the input rotation switching valve will open the oil passage and hydraulic pressure will be output from the hydraulic source via the output port. be done. This output oil pressure is supplied to the gear ratio switching valve, but if the continuously variable transmission has returned to the low gear ratio,
Since there is no need to intentionally shift to a lower gear ratio, the gear ratio switching valve does not output oil pressure. On the other hand, if the continuously variable transmission has not returned to the lower gear ratio, the gear ratio switching valve outputs hydraulic pressure to the regulator valve as a signal pressure. It outputs hydraulic pressure and increases the line pressure to increase the thrust of the driven pulley, forcing a downshift to a lower speed ratio. This allows the vehicle to return to a low speed ratio that allows it to restart when it comes to a stop, ensuring agile starting performance.

〔Example〕

FIG. 1 shows an example of a continuously variable transmission for a vehicle according to the present invention.

An engine output shaft l drives a pump impeller 3 of a torque converter 2, and a turbine runner 4 is connected to an input shaft 10. Further, the stator 5 is connected to a fixed part 7 such as a case via a one-way clutch 6. Furthermore, a lock-up clutch 8 connected to one end of the input shaft IO is disposed inside the torque converter 2, and by applying hydraulic pressure behind the lock-up clutch 8, the pump impeller 3 and the turbine runner 4 are connected to each other. Directly connect.

At the other end of the input shaft 10, a forward/reverse switching mechanism 11 made of a double Simpson planetary gear mechanism is provided. This forward/reverse switching mechanism 11 includes a sun gear 12 connected to an input shaft 10, a ring gear 13, and a continuously variable transmission 20, which will be described later.
A carrier 14 connected to a drive shaft 21 of the carrier 1
4, and meshes with the sun gear 12.
A planetary gear 15 and a second planetary gear 1 rotatably supported by the carrier 14 and meshing with the ring gear 13.
A forward clutch 17 is provided between the input shaft 10 (sun gear 12) and the carrier 14, and a reverse clutch 19 is provided between the ring gear 13 and a fixed part 18 such as a case. is provided. Forward clutch 1
7 and releases the reverse clutch 19, the sun gear 12 and the carrier 14 rotate together to become a forward drive state, and the forward clutch 17 is released and the reverse clutch 1
9, the carrier 14 rotates in the opposite direction with respect to the sun gear 12 and enters a backward drive state. Furthermore, when both clutches 17, 19 are released simultaneously, a neutral state is achieved.

The continuously variable transmission 20 includes a drive pulley 2 provided on a drive shaft 21.
2, a driven pulley 24 provided on the driven shaft 23, and a heald 25 wound between both pulleys. The drive side boob IJ22 has a fixed sheave 22a and a movable sheave 2.
2b, and a gear ratio control oil chamber 2G for controlling the gear ratio is provided behind the movable sheave 22b. On the other hand, the driven pulley 24 also has a fixed sheave 24 in the same way.
a and a movable sheave 24b, the movable sheave 2
■ Belt 25 behind the belt 4b provides the thrust necessary for torque transmission.
An oil chamber 27 for controlling thrust force is provided. The oil pressure in the gear ratio control oil chamber 26 and thrust force control oil chamber 27 is controlled by a hydraulic control device, which will be described later. An end 28a of a gear ratio detection rod 28 is engaged with the outer circumference of the movable sheave 22b of the drive pulley 22, and the movable sheave 2
The gear ratio is detected by the movement of 2b. In addition, the tip of the pipe 29 corresponds to the inner circumferential groove 26a provided at the back of the oil chamber 26 of the drive side pulley 22, and the centrifugal hydraulic pressure of the oil leaking from the oil chamber 26 is detected, and the The rotation speed of the side pulley 22, that is, the input shaft 10 is detected.

A reduction gear 30 is fixed to the end of the driven shaft 23,
This reduction gear 30 is connected to a ring gear 35 of a differential device 34 via gears 32, 33 of a counter shaft 31, and the differential device 34 transmits power to two output shafts 36, 37.

FIG. 2 is a shift diagram of the continuously variable transmission constructed as described above.

In the figure, when the vehicle first starts running, it starts from point A at a gear ratio greater than the lowest gear ratio (Low) of the continuously variable transmission 20 due to the operation of the torque converter 2. and,
At point B, the torque converter 2 completes the long rotation and starts the speed change control of the continuously variable transmission 20. That is, while shifting the gear ratio to the high speed ratio side from point B, both the engine rotation speed and the vehicle speed are increased to the target engine rotation speed corresponding to the throttle opening degree. Eventually, the maximum speed ratio ()
When reaching (point 0) (point 0), the vehicle continues traveling while maintaining that gear ratio.

When decelerating from the maximum speed ratio, the maximum speed ratio is maintained until the target engine speed N when the throttle is fully closed, and when this engine speed is reached (point D), the gear shift is started to the lower speed ratio side. . Then, when the lowest speed ratio is reached (point E), the long-up of the torque converter 2 is canceled, the vehicle moves to the converter operating range, and the vehicle comes to a stop.

In the above-mentioned continuously variable transmission, the converter operating pressure of the torque converter 2 and the lock-up operating pressure of the forward clutch 1
7. Reverse clutch 19. Oil chamber 2 of drive side boo 1J22
6 and the oil chamber 27 of the driven pulley 24 are
It is controlled by the hydraulic control device shown in the figure. This hydraulic control device generally includes an oil pump 40, an L/curator valve 50, a constant pressure valve 60, a throttle valve 70, a sub-shift door valve 80, a manual valve 90, a lock-up valve lOO, and a reverse stop valve 1.
1O, an engine brake valve 120, etc.

The regulator valve 50 is a valve for regulating the discharge pressure of the oil pump 40 to a desired line pressure.
The discharge pressure of 0 is the input port 51a and the first signal port 51.
b and presses the spool 52 to the right, and the spring 53 opposes this and presses the spool 52 to the left via the plunger 54. First signal port 51b
(When the oil pressure becomes high, the spool 52 moves to the right and discharges the oil pressure of the input port 51a to the constant pressure valve 60 via the oil drain port 51c. The spring receiver 55 supporting the spring 53 is linked to the gear ratio detection iron 2B engaged with the drive pulley 22 via the gear ratio detection lever 56.
The gear ratio is low gear ratio (L.

As it moves to the w) side, the spring receiver 55 is pushed to the left. The left end of the regulator valve 50 is formed with a second signal port 51d to which oil pressure corresponding to the input rotational speed is input from the pitot tube 29, and a third signal port 51e to which a constant pressure is input from a constant pressure valve 60, which will be described later. A fourth signal port 51f to which throttle pressure is input from the throttle valve 70 is formed in the intermediate portion. The spring receiver 55 also serves as a gear ratio switching valve according to the present invention, and opens and closes a first auxiliary port 51g that guides hydraulic pressure from a reverse stop valve 110, which will be described later, and a second auxiliary port 51h adjacent to this auxiliary port. do. Then, when the gear ratio becomes the set gear ratio l, higher speed ratio side, in other words, when the spring receiver 55 moves to the right from the predetermined position, the first auxiliary port 51g and the second auxiliary port 51h communicate with each other, and the reverse The hydraulic pressure from the stop valve 110 is applied to the third auxiliary port 51 for pushing the plunger 54 to the left.
input to j. In this way, the sum of the loads due to the line pressure acting on the first signal port 51b, the pitot pressure acting on the second signal port 51d, and the constant pressure acting on the third signal port 51e, and the spring 53 corresponding to the gear ratio. The line pressure is regulated by balancing the load with the sum of the loads caused by the throttle pressure acting on the third signal port 51f and the hydraulic pressure acting on the third auxiliary port 51i. This line pressure is applied to the oil chamber 27 of the driven pulley 24 and the throttle valve 7, which will be described later.
0) is supplied to the speed change control valve 80 via 75a.

The constant pressure valve 60 is a valve that outputs a constant oil pressure lower than the line pressure, and the oil pressure is input to the input port 1 from the drain port 51c of the regulator valve 50, and this oil pressure is also input to the left signal port 62. Then, the spool 63 depends on the oil pressure input to the signal port 62! , 7”I
It is pushed to the right against the connector 64 and opens the drain port 65. Therefore, the output oil pressure is regulated to a constant pressure that balances the spring 64.

The throttle valve 70 has a plunger valve 70 that contacts the circumferential surface of a throttle 7 torque cam 71 that rotates in conjunction with the accelerator pedal.
2, and a spool 74 that is pushed leftward by a plunger 72 via a spring 73. port 7
Line pressure is input to port 5a, and throttle pressure is input from port 75b to third signal port 5 of regulator valve 5°.
1f and the input port 92a of the manual valve 9o. Also, the throttle pressure is controlled by the communication hole 7 of the spool 74.
4a to the left end port 75c, and this throttle pressure pushes the spool 74 to the right. Therefore, the throttle valve 70 is operated in accordance with the throttle opening. Note that the throttle pressure is also input to the right port 75d, and this throttle pressure pushes the plunger 72 to the left, reducing the reaction force of the spring 73 against the throttle cam 71 and reducing the pressing force on the accelerator pedal. ing. Furthermore, the converter working pressure is inputted to the bow) 75e from a lock-up valve 100, which will be described later, and when the plunger 72 operates beyond a certain opening degree, the ports 75e and 75f communicate with each other, and the converter working pressure is guided to the port 75g. Therefore, in the converter operation range where the throttle opening is above a certain level, the throttle pressure is increased, the hydraulic pressure led to the forward clutch 17 via the manual valve 90 is increased, and clutch slippage is prevented. It can be prevented. At the same time, the line pressure is also increased, so the thrust of the driven pulley 24 is increased, and belt slip can be prevented.

The speed change control valve 80 includes a cam rod 82 that contacts the circumferential surface of the throttle cam 81 that rotates in conjunction with the throttle cam 71 of the throttle valve 70, a plunger 84 that is pushed leftward by the cam rod 82 via a spring 83, and a plunger 84. It includes a spool 86 that is pushed leftward by the middle 84 via a spring 85, and a spring 87 that biases the spool 86 rightward. Line pressure is input to the input port 80a, and gear ratio control pressure is output from the output port 80b to the lock-up valve 100 and the oil chamber 26 of the drive pulley 22.

Moreover, oil pressure corresponding to the rotational speed of the input shaft IO is guided from the pitot tube 29 to the left end signal port 80c. Therefore, the speed change control valve 80 is controlled by the rotational speed of the input shaft 10 and the throttle opening. Note that pitot pressure is also input to the rightmost bow (bow) 80d, thereby reducing the force required to press the accelerator pedal.

In addition to the spring 85, another spring 88 is interposed between the spool 86 and the plunger 84, and the right end of this spring 88 is in contact with an operating piece 89.

This operation piece 89 is linked with the gear ratio detection rod 28 that is engaged with the drive pulley 22, and the gear ratio is set to a low speed ratio (Lo
w) As the operation piece 89 moves to the left,
Pushing the spool 86 to the left via the spring 88, as a result, the speed starts to change gradually from the lowest speed ratio (point B) to the high speed ratio side as shown in Fig. 2, eliminating overshoot and improving the running speed. The ring has been improved.

The manual valve 90 moves to P in conjunction with the shift lever.

It has a spool 91 that is operated at each position of R, N, D, and L, and a total of three ports 92b to 92d whose oil passages are switched by this spool 91 are provided. Throttle pressure is input from the throttle valve 70 to the input port 92a, and the port 92b communicating with the input port 92a in the D and L ranges is connected to the forward flange 1.
7 is connected. Further, in the R range, a port 92c communicating with the input port 92a is connected to a reverse stop valve 110, which will be described later. Furthermore, port 9 at one end
2d communicates with the input port 92a only in the L range, and supplies throttle pressure to an engine brake valve 120, which will be described later.

The lock-up valve 100 is a valve that switches between a converter operating range and a lock-up operating range of the torque converter 2. A constant pressure is input from the constant pressure valve 60 to the input port 01a of this valve, and a gear ratio control pressure is input from the gear change control valve 80 to the right end signal port 101b. There are output capos on the left and right sides of the input port 101a) 101c, 101d.
The right output port 101C is connected to the lock-up oil chamber 2a of the torque converter 2, and the left output port 101d is connected to the converter oil chamber 2b of the torque converter 2. The spool 102 is switched to the left when the gear ratio control pressure input to the signal baud (101b) becomes greater than the load of the spring 103. In other words, since the gear ratio control pressure is low in the low speed ratio state, the oil pressure is supplied from the output capo 101d to the converter side oil chamber 2b, and as the gear ratio control pressure increases as the gear ratio shifts to the high speed ratio side, The lock-up valve 100 is switched to the left, and hydraulic pressure is supplied from the output port 101C to the lock-up side oil chamber 2a.

The reverse stop valve 110 is a valve that prevents the reverse clutch 19 from being engaged even if the manual valve 90 is accidentally switched to the R range while the vehicle is running at high speed in the D or L range. This valve 110 has a spool 112 biased leftward by a spring 111, and a signal port 113 at the left end.
Hydraulic pressure corresponding to the rotational speed of the input shaft 10 is led from a pitot tube 29 to the input shaft 10 . In addition, the input port 1-114 is connected to the port 92c of the manual valve 90, and the output port 1-114 is connected to the port 92c of the manual valve 90.
15 is connected to the reverse clutch 19.9As the rotational speed increases, the pitot pressure also increases, so the spool 112 switches to the right against the spring 111.
The oil path to the retreating flange 19 is shut off. Further, the reverse stop valve 110 also serves as an input rotation switching valve according to the present invention, and the port 1 to which constant pressure is input from the constant pressure valve 60
16 and a port 117 connected to the first auxiliary port 51g of the regulator valve 50. These ports 116 and 117 are in communication when the pitot pressure is low (input rotational speed is low), and are cut off when the pitot pressure becomes higher than a certain value.

The engine brake valve 120 is a valve for maintaining the gear ratio on the low speed ratio side regardless of the throttle opening in the L range and operating the engine brake. This valve 12
The shaft 82a engaged with the spool 121 of
This is the roller shaft of the cam rod 82 of No. 0, and the spool 121 and the cam rod 82 interlock with each other. When the manual valve 90 is operated to the L range, the oil pressure is transferred to the port 12.
2, the spool 121 is moved to the left. As a result, the cam rod 82 of the speed change control valve 80 moves to the left via the roller shaft 82a, and pushes the spool 86 to the left via the springs 83, 85. As a result, the oil chamber 26 of the drive pulley 22 The oil pressure decreases and the gear is shifted to a lower speed ratio.

Here, the downshift operation at the time of a sudden stop according to the present invention will be explained.

When decelerating from the maximum speed ratio as shown in Figure 2,
The engine decelerates according to the maximum speed ratio until the target engine speed when the throttle is fully closed (point D), then starts shifting toward a lower speed ratio while maintaining the target engine speed, and when it reaches the lowest speed ratio (E point), the torque converter 2 enters the converter operating range and comes to a stop. However, if a sudden brake is applied while driving at the highest speed ratio, the process from point D as shown by the broken line will occur, and the continuously variable transmission 20 will stop moving at the intermediate speed ratio.
may stop. In contrast, in the present invention, when the input rotational speed is equal to or less than the set speed N and the gear ratio is smaller than the set gear ratio i (indicated by diagonal lines in FIG. 2), the spring retainers of the reverse stop valve 110 and the regulator valve 50 55, hydraulic pressure is introduced to the port 51i of the regulator valve 50, and the line pressure is increased. Since the line pressure is guided to the oil chamber 27 of the driven pulley 24, the driven side boot IJ24
thrust increases, forcing a downshift to a lower speed ratio. As a result, when the vehicle comes to a stop, the vehicle returns to or near the lowest speed ratio (Low), making it possible to restart quickly.

In the above embodiment, the reverse stop valve 110 also serves as the input rotation switching valve, and the flap receiver 55 of the regulator valve also serves as the gear ratio switching valve, but this is to simplify the hydraulic circuit. A dedicated valve may be used.

〔Effect of the invention〕

As is clear from the above explanation, according to the present invention, the line pressure is increased by the action of the input rotation switching valve and the gear ratio switching valve, so that when a sudden stop is made from a high speed ratio running state, the driven pulley It is possible to increase thrust and force downshift to a lower speed ratio. This allows the vehicle to return to a low speed ratio that allows it to restart when it comes to a stop, ensuring agile starting performance.

[Brief explanation of drawings]

FIG. 1 is a skeleton diagram showing the configuration of a continuously variable transmission for a vehicle according to the present invention, FIG. 2 is a transmission diagram thereof, and FIG. 3 is a circuit diagram of a hydraulic control device. 1... Engine output shaft, 2... Torque converter,
12... Forward/forward switching mechanism, 17... Forward clutch, 19... Reverse brake, 20... V-held continuously variable transmission, 22... Drive side pulley, 24... Follower Side pulley, 26.27... Oil chamber, 29... Pitot pipe, 40... Oil pump, 5o... Regulator valve, 55... Splash receiver (gear ratio switching valve), 70... Throttle valve, 80... Speed change control valve, 100... Lock-up valve, 110... Reverse stop valve (input rotation switching valve). Patent applicant Daihatsu Motor Co., Ltd. Agent Patent attorney Hidetaka Tsutsui Figure 1 Figure 2 Vehicle speed (ka/h)

Claims (1)

[Claims] An engine output shaft is connected to a driving pulley of a V-belt continuously variable transmission, and a driven pulley is connected to an axle,
The regulator valve regulates the discharge pressure of the oil pump to a line pressure that corresponds to the gear ratio and input rotational speed, and guides this line pressure to the oil chamber of the driven pulley. In a continuously variable transmission for vehicles that supplies line pressure to the oil chamber of the drive pulley according to the input rotation speed, the input rotation speed opens the oil path from the hydraulic source to the output port when the input rotation speed is less than the set speed. A switching valve is provided, and a transmission ratio switching valve receives the output oil pressure of the input rotation switching valve and guides the output oil pressure as a signal pressure to the regulator valve when the transmission ratio is smaller than the set transmission ratio. A hydraulic control device for continuously variable transmissions for vehicles, characterized by a regulator valve that regulates line pressure to a high level.