JPH0634036A - Oil pressure controller for automatic transmission - Google Patents

Abstract

PURPOSE:To avoid deterioration of a pressure regulating accuracy of a pressure regulating valve even in the case where a flow exists in a hydraulic circuit in an automatic transmission where the pressure regulating valve is disposed upstream of a shift vale for supplying and discharging an operating oil pressure to be supplied to a hydraulic actuator. CONSTITUTION:A converter line 48, to which a line pressure is supplied, is branched to two lines, one of which can be communicated with an engagement line 41 connected to an engagement chamber 19a of a lock up clutch by means of a lock up shift valve 44 while the other of which is connected to a control valve 45 for regulating a differential pressure so that an intermediate line 50, to which the regulated pressure is input, can be communicated with an engagement line 42 connected to a releasing chamber 19b of the clutch by means of the shift valve 44. A first feedback line 59 branched from the engagement line 41 downstream of the shift valve 44 is connected to a first feedback port 45f provided in a control valve 45.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control system for an automatic transmission, and more particularly to a hydraulic control system for an automatic transmission in which a pressure regulating valve is installed upstream of a shift valve.

[0002]

2. Description of the Related Art Generally, an automatic transmission mounted on an automobile is equipped with a torque converter which is a kind of fluid coupling. It is usual that the hydraulic oil is constantly supplied and the hydraulic oil discharged from the torque converter is supplied to each part as lubricating oil.

On the other hand, in this type of torque converter, a lock-up clutch is provided which directly connects an input element to which an engine output is input and an output element which is driven by the rotation of the input element through fluid. A so-called lock-up state in which torque is mechanically transmitted by directly connecting an output element with a lock-up clutch, a so-called converter state in which torque is transmitted via fluid (lock-up release state)
Also, there is a type in which three types of transmission modes in a so-called lock-up slip state in which torque transmission via fluid and mechanical torque transmission by a lock-up clutch are used together can be selected.

For example, in Japanese Laid-Open Patent Publication No. 2-120568, a hydraulic circuit for supplying a control hydraulic pressure to a lockup clutch provided in a torque converter supplies and releases the engagement pressure supplied to an engagement chamber of the lockup clutch. A shift valve having two spools for switching between supplying and discharging the release pressure supplied to the chamber, and adjusting the release pressure supplied to the release chamber via the shift valve to adjust the differential pressure from the engagement pressure. When the two spools provided on the shift valve shift to one side, the fastening pressure is introduced only into the fastening chamber to fasten the lockup clutch, and both spools move to the other side. When shifting, the release pressure is introduced only in the release chamber to release the lockup clutch, and the spools are opposed so that they are separated from each other. When shifted, the configuration in which the slip control of the lockup clutch engagement force corresponding to the pressure difference between the release pressure and engaging pressure is adjusted by the pressure regulating valve is shown.

In this slip control, for example, the output port of the pressure regulating valve, which communicates with the release chamber of the torque converter via the shift valve, is selectively used as the input port and the drain port to which the original pressure is supplied by the movement of the spool. It is configured to be able to communicate, and by inputting the release pressure and the engagement pressure as feedback, the output port is communicated with the input port when the pressure difference between the release pressure and the engagement pressure is smaller than a predetermined value. When it becomes larger than a predetermined value, the output port is communicated with the drain port so that the differential pressure between the release pressure and the fastening pressure is maintained in a constant state. It is customary to branch the feedback passage from near the pressure regulating valve, as also shown.

[0006]

By the way, in this type of torque converter, the slip control is performed in a state where the hydraulic oil is constantly supplied. When there is a flow in the hydraulic oil in this way, Due to the pressure loss due to the flow path resistance due to the shift valve, the feedback pressure input to the pressure regulating valve does not reflect the pressure in the engagement chamber of the lockup clutch, for example, and the pressure regulating characteristics vary. In particular, on the side of the fastening chamber where most of the hydraulic oil is introduced, the above-mentioned phenomenon becomes prominent accordingly.

Such a problem is caused by the provision of a shift valve for switching the supply and discharge of the working oil pressure in the hydraulic circuit for supplying the working oil pressure to the hydraulically actuated actuator, and by the pressure regulating valve arranged upstream of the shift valve. In the one in which the operating hydraulic pressure supplied to the actuator via the shift valve is feedback-adjusted,
It occurs widely when flow occurs in the hydraulic circuit.

The present invention addresses the above-mentioned problems in the hydraulic circuit of an automatic transmission in which a pressure regulating valve is arranged upstream of a shift valve that supplies and discharges operating hydraulic pressure supplied to a hydraulically actuated actuator. The purpose of the present invention is to prevent deterioration of the pressure regulation accuracy of the pressure regulating valve even when there is a flow in the hydraulic circuit.

[0009]

That is, a hydraulic control device for an automatic transmission according to claim 1 of the present application (hereinafter referred to as the first invention) includes a hydraulic circuit for supplying a hydraulic pressure to a hydraulically actuated actuator. A shift valve for switching between supply and discharge of the working oil pressure and a pressure adjusting valve arranged upstream of the shift valve for feeding back and adjusting the working oil pressure supplied to the actuator via the shift valve are provided. In the automatic transmission, a feedback passage for feedback input to the pressure regulating valve is branched from a downstream side of the shift valve.

A hydraulic control device for an automatic transmission according to claim 2 of the present application (hereinafter referred to as the second invention) is a lock for directly connecting an input side and an output side to a fluid coupling for transmitting an engine output to a transmission mechanism. An up-clutch is provided, and a hydraulic circuit that supplies a control hydraulic pressure to the lock-up clutch is provided with an engagement pressure that is supplied to an engagement chamber that engages the lock-up clutch and a release chamber that releases the engagement state. An automatic transmission provided with a shift valve for switching between supply and discharge of pressure, and a pressure regulating valve which is arranged on an upstream side of the shift valve and which regulates a differential pressure between a release pressure and a fastening chamber. It is characterized in that a feedback passage for feedback input is branched from at least a coupling chamber side passage downstream of the shift valve.

[0011]

According to the above construction, the following operation can be obtained.

That is, according to the first aspect of the invention, since the feedback passage for feedback input to the pressure regulating valve is branched from the downstream side of the shift valve, the pressure regulating characteristic is deteriorated even if there is a flow in the hydraulic circuit. Will be avoided.

In particular, according to the second aspect of the invention, the lockup clutch that directly connects the input side and the output side is provided in the fluid coupling such as the torque converter that transmits the engine output to the transmission mechanism, and the lockup clutch is provided. A shift valve for switching the supply and discharge of the engagement pressure supplied to the engagement chamber of the lock-up clutch and the release pressure supplied to the release chamber, and a hydraulic circuit for supplying the control hydraulic pressure to the lock valve are arranged upstream of the shift valve. In the automatic transmission provided with the pressure adjusting valve that adjusts the differential pressure between the release pressure and the engagement chamber, the above-described action is obtained when slip control of the lockup clutch is performed. This allows the slip control to be performed more accurately.

[0014]

EXAMPLES Examples of the present invention will be described below.

As shown in FIG. 1, an automatic transmission 1 according to this embodiment has a torque converter 10, a main transmission 20 arranged on the same axis as the torque converter 10, and a main transmission 20 parallel to these axes. And an auxiliary transmission 30 arranged on the axis.

The torque converter 10 includes a pump 12 integrated with a case 11 connected to the engine output shaft 2,
A turbine 13 arranged to face the pump 12 and driven by the pump 12 via hydraulic oil, and disposed between the pump 12 and the turbine 13 and supported by the transmission case 3 via a one-way clutch 14. Stator 1
5, a converter output shaft 16 connected to the turbine 13, and a lockup clutch 17 that directly connects the output shaft 16 to the engine output shaft 2 via the case 11.

The torque converter 10 and the main transmission 2
An oil pump 4 driven by the engine output shaft 2 via the torque converter 10 is disposed between the oil pump 4 and the engine.

The main transmission 20 has a converter output shaft 1
6 has a front planetary gear mechanism 21 arranged on the torque converter side and a rear planetary gear mechanism 22 arranged on the counter torque converter side. The converter output shaft 16 is connected to the sun gear 21a of the front planetary gear mechanism 21 via the forward clutch 23 and the sun gear 2 of the rear planetary gear mechanism 22 via the direct coupling clutch 24.
The sun gear 21a of the front planetary gear mechanism 21 and the ring gear 22b of the rear planetary gear mechanism 22 are coupled to each other.

Further, a first one-way clutch 25 and a low reverse brake 26 are arranged in parallel between the ring gear 21b of the front planetary gear mechanism 21 and the transmission case 3, and the rear planetary gear mechanism 22 has a structure. A second one-way clutch 27 and a 3-4 brake 28 are arranged in series between the sun gear 22a and the transmission case 3, and a coast brake 29 for engine braking is arranged in parallel with them. Then, the pinion carriers 21c, 22c of the front planetary gear mechanism 21 and the rear planetary gear mechanism 22 are coupled, and these are connected to the main transmission 2
An intermediate gear 5 that transmits power from 0 to the auxiliary transmission 30 is connected.

With such a structure, the main transmission 20
According to the above, the forward clutch 23, the direct coupling clutch 24,
By selectively engaging the 3-4 brake 28 and the low reverse brake 26, a forward low speed stage, a medium high speed stage, a high speed stage and a reverse stage can be obtained.

On the other hand, the sub-transmission 30 has a single planetary gear mechanism 31, and the intermediate gear 6 which is always meshed with the intermediate gear 5 in the main transmission 20 is connected to the ring gear 31a of the planetary gear mechanism 31. And the ring gear 31
A direct coupling clutch 32 is arranged between a and the sun gear 31b, and a third one-way clutch 33 and a reduction brake 34 are arranged in parallel between the sun gear 31b and the transmission case 3. Then, the planetary gear mechanism 31
The output gear 7 is connected to the pinion carrier 31c of the left and right drive wheels (not shown) from the gear 7 through a differential device.
Power is transmitted to.

The sub-transmission 30 can shift the power input from the main transmission 20 via the intermediate gears 5 and 6 to two forward gears, a low-speed gear and a high-speed gear, and output it to the output gear 7. It is like this.

That is, when the direct coupling clutch 32 is released, the sun gear 31 of the planetary gear mechanism 31 is driven by the third one-way clutch 33 or the reduction brake 34.
By fixing b, the power from the intermediate gear 6 input to the ring gear 31a of the planetary gear mechanism 31 is decelerated and output from the pinion carrier 31c to the output gear 7, whereby a low speed stage is obtained. In this case, if the deceleration brake 34 is engaged, the auxiliary transmission 30
As a single unit, the engine brake will operate.

Further, the direct coupling clutch 32 is engaged,
When the deceleration brake 34 is released, the ring gear 31a and the sun gear 31b of the planetary gear mechanism 31 are coupled to each other, whereby the power from the intermediate gear 6 is directly output from the pinion carrier 31c to the output gear 7.
As a result, a high speed stage (direct connection stage) can be obtained.

In this way, the main transmission 20 can obtain three forward gears and one reverse gear, and the auxiliary transmission 3
By setting 0, two high and low speed stages can be obtained with respect to the output of the main transmission 20, so that the automatic transmission as a whole can obtain 6 shift stages for forward movement and the main shift for reverse movement. The combination of the reverse gear of the machine 20 and the low gear of the auxiliary transmission 30 to which the deceleration brake 34 is engaged provides the reverse gear as a whole. And in this example,
As the forward shift speed, a predetermined five speeds among the above six speeds are adopted.

Table 1 is a summary of the operating states of the clutches and brakes at each of the five forward gears and one reverse gear. In addition, in Table 1, (◯) indicates that the engagement is performed only in the range for engine braking.

[0027]

[Table 1] Here, as shown in FIG. 2, the lockup clutch 17 provided in the torque converter 10 has the above-mentioned turbine 1
3 and a case 11 connected to the engine output shaft 2, and a torsion damper 17a and a damper piston 17b, which rotate integrally with the turbine shaft 16, and a case 1 at a position facing the damper piston 17b.
1 and a friction plate (not shown). The space in the case 11 is the same as the damper piston 17b.
Is divided into a lock-up fastening chamber (hereinafter referred to as fastening chamber) 19a on the turbine side and a lock-up release chamber (hereinafter referred to as release chamber) 19b on the case side, and
They communicate with each other at the top.

The hydraulic pressure supplied to the fastening chamber 19a via the fastening line 41 from the hydraulic circuit 40 is applied to the damper piston 17
b becomes a fastening pressure for lock-up that acts in the direction of pressing the friction plate against the friction plate, and the release chamber 1 is connected via the release line 42.
The hydraulic pressure supplied to 9b serves as a release pressure for releasing the lock-up that acts in the direction of separating the damper piston 17b from the friction plate. Then, the damper piston 17b is frictionally engaged with the friction plate by the fastening force corresponding to the differential pressure between the release pressure and the fastening pressure. Excess hydraulic oil in the fastening chamber 19a is discharged through the drain line 43. On the other hand, the excess hydraulic oil in the release chamber 19b flows out into the fastening chamber 19a through the upper space of the damper piston 17b, and then is discharged through the drain line 43 in the same manner as above.

Next, referring to FIG. 3, the hydraulic circuit 40 for controlling the operation of the lockup clutch will be described. The hydraulic circuit 40 includes a lockup shift valve for controlling the lockup clutch 17 in the torque converter 10. 44 and lock-up control valve 4
5, an ON-OFF solenoid valve 46 for controlling the operation of these valves 44 and 45, and a duty solenoid valve 47.

Control valve 4 for lock-up
5 is an input port 4 to which the converter line 48 is connected
5a, a drain port 45b to which a drain line 49 for leaking hydraulic oil is connected, and an output port 45c to which an intermediate line 50 leading to the lockup shift valve 44 is connected, and provided at one end of the valve 45. The control valve 45d has a reducing valve 51
A first control line 52 derived from is connected. Then, the duty solenoid valve 47 is installed in the control line 52, and the control pressure adjusted by the valve 47 is supplied to the control port 45d and acts on the spool 45e to be supplied from the converter line 48. The line pressure is adjusted and output from the output port 45c to the intermediate line 50.

When the duty ratio of the control signal output from the controller (described later) is 100, the duty solenoid valve 47 completely discharges the first control line 52 to set the control pressure to 0. When the duty ratio is 0, the control pressure of the first control line 52 is set to the maximum pressure.

On the other hand, the lock-up shift valve 44
Are the first and second spools 44a, 44 arranged in series.
a first spool 44 having a right side b in FIG.
A second control line 54 guided from a main line (not shown) via a line 53 is connected to the control port 44c formed on the right side of a, and the ON-OFF solenoid valve is connected to the control line 54. 46 is installed.

The lock-up shift valve 44 includes:
The first input port 44d connected to the converter line 48, the second input port 44e connected to the intermediate line 50 from the control valve 45, and the engagement line 41 communicating with the engagement chamber 19a of the lock-up clutch 17 are provided. A first output port 44f connected thereto and a second output port 44g connected to a release line 42 communicating with the release chamber 19b of the clutch 17 are provided, and the first spool 44a is located on the right side in the drawing. When you do the first
The input port 44d and the first output port 44f communicate with each other,
Further, when the second spool 44b is located on the left side in the drawing, the second input port 44e and the second output port 44g communicate with each other. A branch line 55, which is branched from the first control line 52 for generating the control pressure adjusted by the duty solenoid valve 47, is connected to an intermediate portion between the first and second spools 44a and 44b.

Further, the first input port 44d provided on the lock-up shift valve 44 is connected to the fastening line 4
1st output port 44f to which 1 is connected, and release line 4
The bypass line 56 branched from 2 is configured to be selectively communicable with the connected bypass port 44h, and the first spool 44a is communicated with the drain port while being positioned on the right side in the drawing. The drain line 49 from the control valve 45 is connected to the communication port 44i provided in the.

A pressure holding valve 57 is installed on the drain line 43 connected to the engagement chamber 19a of the lockup clutch 17 in the torque converter 10 to maintain a constant pressure state, and the pressure holding valve 57 leaks. After the hydraulic oil is cooled by the cooler 58, a part of the hydraulic oil is supplied to each part as lubricating oil.

The first feedback line 45f, which is formed on the right side of the drain port 45b of the control valve 45, is connected to the first feedback line 59 branched from the fastening line 41. Together with the input port 45a of the valve 45
A second feedback line 60 branched from the intermediate line 50 on the upstream side of the lock-up shift valve 44 is connected to the second feedback port 45g formed on the left side of the lock-up shift valve 44.

In this embodiment, the first feedback line 59 for feedback inputting the engagement pressure.
Is branched from the vicinity of the valve body surface 61 in which the control valve 45 is built.

Here, the branch line 55 leading to the first control line 52 is connected to the forward clutch 2 via the line 62.
3 is connected to the control port 63a at one end of the bypass valve 63 for bypass control.

The bypass 63 is installed in the forward line 64 leading to the forward clutch 23, and the orifice 6 having a different throttle amount when the hydraulic oil is supplied and when the hydraulic oil is discharged.
5, an input side bypass port 63b to which an upstream line 66 branched from the forward line 64 from the upstream side of 5 is connected, and an output side to which a downstream line 67 that joins the forward line 64 on the downstream side of the orifice 65 is connected. A bypass port 63c is provided and a line 62 branched from the branch line 55 to the control port 63a.
When the spool 63d moves in accordance with the control pressure introduced via the input / output side bypass ports 63b and 63c as shown in the figure, the input / output side bypass ports 63b and 63c are blocked. It can be switched between the state of communication.

The forward line 64 is located on the downstream side of the orifice 65, and the accumulator 6 is provided to alleviate the shock when the fastening pressure is supplied to the forward clutch 23.
8 are installed.

Here, in this automatic transmission, as shown in FIG. 4, the solenoid valve 4 for lock-up control is used.
6, 47 and various solenoid valves 69 ... 69 for shifting
A controller 100 for controlling the above is provided, and each solenoid valve is controlled by a control signal from the controller 100. The controller 100 includes a signal from a sensor 101 for detecting a vehicle speed and a sensor 102 for detecting an engine throttle opening.
From the sensor 103 for detecting the shift position (range) selected by the driver, and the solenoid valves are turned on according to the driving condition indicated by these signals and the driver's request. It is designed to be controlled.

According to this structure, the ON-OFF solenoid valve 46 is turned ON, the second control line 54 leading to the control port 44c of the lockup shift valve 44 is discharged, while the duty ratio of the duty solenoid valve 47 is increased. Is set to 0 and the first control line 52
As shown in FIG. 3, the control pressure of the first and second spools 4 of the lock-up shift valve 44 is set to the maximum pressure.
4a and 44b shift in opposite directions. As a result, the release pressure adjusted by the control valve 45 is introduced into the release chamber 19b via the intermediate line 50 and the release line 42, and the converter line 48 and the fastening line 41 are connected to the fastening chamber 19a. The line pressure is directly introduced through the lockup clutch 17, so that the lockup clutch 17 is slip-controlled according to the pressure difference between the two (fastening pressure-release pressure).

If the control pressure is reduced from this state, the second
When the spring pressing force acting on the right end side of the spool 44b overcomes the pressing force by the control pressure acting from the opposite side, the second spool 44b is positioned on the right side in the drawing and is released from the intermediate line 50. The communication with the line 42 is cut off, and the lockup clutch 17 is locked by the fastening pressure supplied to the fastening chamber 19a as described above.
Will be completely fastened.

That is, in this embodiment, a differential pressure varying with the characteristic as shown in FIG. 5 is obtained with respect to the duty ratio output to the duty solenoid valve 47. The lockup clutch 17 is completely engaged in the range of X, and the lockup clutch 17 is slip-controlled in the range of region Y.

By the way, during the slip control, the fastening pressure and the release pressure are applied to the first and second feedback ports 45f and 45g provided in the control valve 45 via the first and second feedback lines 59 and 60. Feedback is input, but the first feedback line 59 for inputting the engagement pressure as feedback.
However, the lock-up shift valve 44 is connected from the engagement line 41 that supplies the engagement pressure to the engagement chamber 19a where the amount of hydraulic oil is large.
Since the pressure is fed back to the control valve 45, the pressure fed back to the control valve 45 reflects the pressure in the engagement chamber.
The slip control of 1 is performed well.

When the ON-OFF solenoid valve 46 is turned off, the first and second spools 44a, 4a
4b will be located on the left side, and the middle line 5
While 0 communicates with the release line 42, the communication state between the converter line 48 and the fastening line 41 is cut off. As a result, the lockup clutch 17 is completely released.

Further, the second feedback line 60 connected to the second feedback port 45g of the control valve 45 may be branched from the release line 42 downstream of the lockup shift valve 44 as shown by the chain line in the figure. Good. Then, the slip control of the lockup clutch 17 will be performed even better.

Of course, the present invention is not limited to the lockup clutch built in the torque converter.

[0049]

As described above, according to the present invention, in the automatic transmission in which the pressure regulating valve is arranged on the upstream side of the shift valve for supplying and discharging the working hydraulic pressure supplied to the hydraulically actuated actuator, Since the feedback passage for feedback input to the valve is branched from the downstream side of the shift valve, even if there is a flow in the hydraulic circuit, deterioration of the pressure regulation characteristic can be avoided.

Particularly, according to the second aspect of the invention, the fluid coupling for transmitting the engine output to the speed change mechanism is provided with the lock-up clutch which is directly connected to the input side and the output side, and the control hydraulic pressure is applied to the lock-up clutch. A shift valve for switching the supply and discharge of the engagement pressure supplied to the engagement chamber of the lock-up clutch and the release pressure supplied to the release chamber to the hydraulic circuit to be supplied, and the shift valve arranged upstream of the shift valve and engaged with the release pressure. In the automatic transmission provided with the pressure regulating valve that adjusts the differential pressure between the chamber and the chamber, the above-described action is obtained when slip control of the lockup clutch is performed. As a result, slip control can be accurately performed.

[Brief description of drawings]

FIG. 1 is a skeleton diagram of an automatic transmission.

FIG. 2 is a partially enlarged sectional view of a torque converter.

FIG. 3 is a hydraulic circuit diagram of a lockup control portion.

FIG. 4 is a control system diagram of an automatic transmission.

FIG. 5 is a differential pressure characteristic diagram with respect to a duty ratio.

[Explanation of symbols]

 10 torque converter 17 lock-up clutch 19a engagement chamber 19b disengagement chamber 20 main transmission 30 auxiliary transmission 40 hydraulic circuit 41 engagement line 44 lock-up shift valve 45 control valve 59 first feedback line

Claims (2)

[Claims] 1. A shift valve for switching supply and discharge of a working oil pressure to a hydraulic circuit for supplying a working oil pressure to a hydraulically operated actuator, and a shift valve arranged upstream of the shift valve,
In an automatic transmission provided with a pressure regulating valve for feeding back and adjusting an operating hydraulic pressure supplied to the actuator via the shift valve, a feedback passage for feedback input to the pressure regulating valve is provided from the shift valve. Is also a hydraulic control device for an automatic transmission, which is branched from the downstream side. 2. A lockup clutch that directly connects an input side and an output side is provided in a fluid coupling that transmits an engine output to a speed change mechanism, and a lockup clutch is provided in a hydraulic circuit that supplies control hydraulic pressure to the lockup clutch. A shift valve that switches between supply and discharge of the engagement pressure supplied to the engagement chamber of the up clutch and the release pressure supplied to the release chamber, and adjusts the differential pressure between the release pressure and the engagement chamber, which is arranged upstream of the shift valve. In the automatic transmission provided with a pressure regulating valve, a feedback passage for feedback input to the pressure regulating valve is branched from at least a fastening chamber side passage downstream of the shift valve. Machine hydraulic control device.