JP3135992B2 - Hydraulic control device for automatic transmission - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for an automatic transmission, and more particularly to a hydraulic control device for an automatic transmission having a pressure regulating valve 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 type of fluid coupling. Normally, hydraulic oil is constantly supplied, and 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 for directly connecting an input element to which engine output is input and an output element driven via fluid by rotation of the input element is provided. A so-called lock-up state in which the input and output elements are directly connected by a lock-up clutch to mechanically transmit torque, a so-called converter state in which torque is transmitted via fluid (a lock-up release state).
In addition, there is a type in which three types of transmission modes in a so-called lock-up slip state in which both torque transmission via a fluid and mechanical torque transmission by a lock-up clutch are used can be selected.

For example, Japanese Patent Application Laid-Open No. 2-120568 discloses a hydraulic circuit for supplying a control oil pressure to a lock-up clutch provided in a torque converter, and supplying and releasing and releasing engagement pressure supplied to an engagement chamber of the lock-up clutch. A shift valve having two spools for switching between supply and discharge of the release pressure supplied to the chamber, and adjusting a differential pressure between the engagement pressure and the release pressure supplied to the release chamber via the shift valve. When the two spools provided in the shift valve shift to one, the engagement pressure is introduced only into the engagement chamber to engage the lock-up clutch, and both spools are connected to the other. When shifting, the release pressure is introduced only to the release chamber to release the lock-up clutch, and the two spools are separated 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 the slip control, for example, an output port of a pressure regulating valve communicating with a release chamber of a torque converter via a shift valve is selectively connected to an input port to which original pressure is supplied by movement of a spool and a drain port. In addition to being configured to be able to communicate with each other, the output port is communicated with the input port when the differential pressure between the release pressure and the engagement pressure is smaller than a predetermined value by feedback-inputting the release pressure and the engagement pressure. When the output pressure is 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 engagement pressure is maintained in a constant state. It is customary to diverge the feedback passage from near the pressure regulating valve as shown in FIG.

[0006]

By the way, in this type of torque converter, slip control is performed in a state in which hydraulic oil is constantly supplied. Due to the pressure loss caused by the flow path resistance of the shift valve and the like, the feedback pressure input to the pressure regulating valve does not reflect, for example, the pressure in the engagement chamber of the lock-up clutch, and the pressure regulation characteristics vary. In particular, on the side of the fastening chamber into which most of the hydraulic oil is introduced, the above-described phenomenon becomes conspicuous.

Such a problem is caused by providing a shift valve for switching the supply and discharge of the operating oil pressure in a hydraulic circuit for supplying the operating oil pressure to the hydraulically operated actuator, and using a pressure regulating valve disposed upstream of the shift valve. In the one in which the operating oil pressure supplied to the actuator through the shift valve is feedback-adjusted,
This will occur widely when a flow occurs in the hydraulic circuit.

The present invention addresses the above-mentioned problem in a hydraulic circuit of an automatic transmission in which a pressure regulating valve is disposed upstream of a shift valve that supplies and discharges a working hydraulic pressure supplied to a hydraulically operated actuator. It is another object of the present invention to avoid deterioration of pressure regulation accuracy of a pressure regulating valve even when there is a flow in a hydraulic circuit.

[0009]

According to a first aspect of the present invention, there is provided a hydraulic control apparatus for an automatic transmission, comprising: 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 regulating valve disposed upstream of the shift valve and feedback-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 a second aspect of the present invention includes a lock that directly connects an input side and an output side to a fluid coupling that transmits an engine output to a transmission mechanism. An up-clutch is provided, and a hydraulic circuit that supplies 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 that is supplied to a release chamber that releases the engagement state. An automatic transmission provided with a shift valve for switching the supply and discharge of pressure and a pressure regulating valve arranged upstream of the shift valve to regulate the differential pressure between the release pressure and the fastening chamber. The feedback passage into which the feedback is input is branched from a passage on the fastening chamber side at least downstream of the shift valve.

[0011]

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

That is, according to the first aspect of the present invention, since the feedback passage fed back 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 present invention, a lock-up clutch directly connected to an input side and an output side is provided in a fluid coupling such as a torque converter for transmitting an engine output to a speed change mechanism. A shift valve for switching between 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 shift valve arranged upstream of the shift valve. In an automatic transmission provided with a pressure regulating valve for adjusting the differential pressure between the release pressure and the engagement chamber, the above-described action can be obtained when the slip control of the lock-up clutch is performed. As a result, the slip control is performed more accurately.

[0014]

Embodiments of the present invention will be described below.

As shown in FIG. 1, an automatic transmission 1 according to this embodiment includes 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 disposed opposite to 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 lock-up 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
Between 0 and 0, an oil pump 4 driven by the engine output shaft 2 via the torque converter 10 is arranged.

The main transmission 20 includes 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 anti-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 to the sun gear 2a of the rear planetary gear mechanism 22 via the direct coupling clutch 24.
2a, the sun gear 21a of the front planetary gear mechanism 21 and the ring gear 22b of the rear planetary gear mechanism 22 are connected.

Between the ring gear 21b of the front planetary gear mechanism 21 and the transmission case 3, a first one-way clutch 25 and a low reverse brake 26 are arranged in parallel. 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 the second one-way clutch 27 and the 3-4 brake 28. Then, the pinion carriers 21c, 22c of the front planetary gear mechanism 21 and the rear planetary gear mechanism 22 are connected, and the main transmission 2
An intermediate gear 5 for transmitting power from the transmission 0 to the auxiliary transmission 30 is connected.

With this configuration, 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 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 always meshed with the intermediate gear 5 in the main transmission 20 is connected to the ring gear 31 a of the planetary gear mechanism 31. And the ring gear 31
A direct connection clutch 32 is disposed between the transmission gear 3 and the sun gear 31b, and a third one-way clutch 33 and a reduction brake 34 are disposed in parallel between the sun gear 31b and the transmission case 3. And, the planetary gear mechanism 31
The output gear 7 is connected to the pinion carrier 31c, and left and right driving wheels (not shown) are connected to the output gear 7 via a differential device.
Power is transmitted to the vehicle.

The sub-transmission 30 can shift the power input from the main transmission 20 via the intermediate gears 5 and 6 into two forward speeds, a low speed stage and a high speed stage, and output the output power to the output gear 7. It has become.

That is, when the direct coupling clutch 32 is released, the sun gear 31 of the planetary gear mechanism 31 is actuated by the third one-way clutch 33 or the deceleration brake 34.
When b is fixed, the power from the intermediate gear 6 input to the ring gear 31a of the planetary gear mechanism 31 is reduced 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 operates.

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, so that the power from the intermediate gear 6 is output from the pinion carrier 31c to the output gear 7 as it is,
As a result, a high-speed stage (directly connected stage) is obtained.

In this manner, the main transmission 20 provides three forward speeds and one reverse speed, and the auxiliary transmission 3
With 0, two high and low gear stages can be obtained with respect to the output of the main transmission 20, so that the automatic transmission as a whole has six gear stages for forward movement, and for the reverse movement, a main gear position for the reverse. The combination of the reverse gear of the engine 20 and the low gear to which the deceleration brake 34 of the auxiliary transmission 30 is engaged provides the overall reverse gear. And in this example,
As the forward gear, five predetermined gears out of the six gears are adopted.

The operating states of the clutches and brakes at each of the five forward speeds and one reverse speed are summarized in Table 1. In Table 1, (○) indicates that the vehicle is engaged only in the engine brake range.

[0027]

[Table 1] Here, as shown in FIG. 2, the lock-up clutch 17 provided in the torque converter 10
3 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 opposed to the damper piston 17b.
1 and a friction plate (not shown). The space in the case 11 corresponds to the damper piston 17b.
The lock-up chamber is divided into a lock-up fastening chamber (hereinafter, referred to as a fastening chamber) 19a on the turbine side and a lock-up release chamber (hereinafter, referred to as a release chamber) 19b on the case side.
The upper part communicates with each other.

The hydraulic pressure supplied from the hydraulic circuit 40 to the fastening chamber 19a via the fastening line 41 is applied to the damper piston 17
b acting on the friction plate in the direction of pressing the friction plate, and the release chamber 1 through the release line 42.
The hydraulic pressure supplied to 9b serves as a release pressure for releasing lockup that acts in a direction to separate the damper piston 17b from the friction plate. Then, the damper piston 17b frictionally engages with the friction plate with a 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, surplus hydraulic oil in the release chamber 19b flows out to the fastening chamber 19a through the upper space of the damper piston 17b, and is discharged through the drain line 43 in the same manner as described above.

Next, a hydraulic circuit 40 for controlling the operation of the lock-up clutch will be described with reference to FIG. 3. The hydraulic circuit 40 includes a lock-up shift valve for controlling the lock-up 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.

The lock-up control valve 4
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 lock-up shift valve 44 is connected, and is provided at one end of the valve 45. The control port 45d has a reducing valve 51
Is connected to the first control line 52 derived from the first control line. The duty solenoid valve 47 is installed on 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.

Here, when the duty ratio of the control signal output from the controller (described later) is 100, the duty solenoid valve 47 completely exhausts the first control line 52 to reduce the control pressure to zero. 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 first and second spools 44a, 44 arranged in series.
b, and a first spool 44 disposed on the right side in the drawing.
A control port 44c formed on the right side of FIG. 3A is connected to a second control line 54 led from a main line (not shown) via a line 53, and the ON-OFF solenoid valve is connected to the control line 54. 46 are provided.

The lock-up shift valve 44 includes:
The first input port 44d to which the converter line 48 is connected, the second input port 44e to which the intermediate line 50 from the control valve 45 is connected, and the fastening line 41 communicating with the fastening 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 positioned on the right side in the drawing. When the first
The input port 44d communicates with the first output port 44f,
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. Further, a branch line 55 branched from the first control line 52 in which the control pressure adjusted by the duty solenoid valve 47 is generated is connected to an intermediate portion between the first and second spools 44a and 44b.

Further, the first input port 44d provided in the lock-up shift valve 44 is connected to the fastening line 4
1 is connected to the first output port 44f connected to the release line 4
The bypass line 56 branched from the second port is selectively communicable with the bypass port 44h connected thereto, and the first spool 44a communicates with the drain port in a state where the first spool 44a is located on the right side in the drawing. The drain line 49 from the control valve 45 is connected to a communication port 44i provided at the port.

A pressure-holding valve 57 is provided on a drain line 43 connected to the fastening chamber 19a of the lock-up 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.

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

In this embodiment, the first feedback line 59 for inputting the engagement pressure in a feedback manner.
Are branched from the vicinity of a 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 a line 62.
3 is connected to a control port 63a at one end of a bypass valve 63 for bypass control.

The bypass 63 is provided with an orifice 6 which is provided on a forward line 64 which communicates with the forward clutch 23 and which has a different throttle amount between when supplying and discharging hydraulic oil.
5, an input side bypass port 63b to which an upstream line 66 branched from a forward line 64 is connected, and an output side to which a downstream line 67 which joins the forward line 64 downstream of the orifice 65 is connected. A bypass port 63c is provided, and a line 62 branched from the branch line 55 is connected to the control port 63a.
When the spool 63d moves in accordance with the control pressure introduced through the inlet and outlet ports 63b and 63c as shown in FIG. The communication state can be switched.

The forward line 64 has an accumulator 6 located downstream of the orifice 65 for reducing a shock when the engagement pressure is supplied to the forward clutch 23.
8 are installed.

Here, as shown in FIG. 4, this automatic transmission has a solenoid valve 4 for lock-up control.
6, 47 and various solenoid valves 69 ... 69 for shifting
A controller 100 is provided for controlling the solenoid valves, and the solenoid valves are controlled by control signals 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.
, A signal from a sensor 103 for detecting a shift position (range) selected by the driver, and the like, and the solenoid valves are operated according to the driving state indicated by these signals or the driver's request. Control.

According to such a configuration, the ON-OFF solenoid valve 46 is turned ON and the second control line 54 communicating with the control port 44c of the lock-up shift valve 44 is discharged, while the duty ratio of the duty solenoid valve 47 is To the first control line 52
By setting the control pressure of the first and second spools 4 of the lockup shift valve 44 as shown in FIG.
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. As a result, the line pressure is directly introduced into the lock-up clutch 17, and the lock-up clutch 17 is slip-controlled according to the pressure difference between the two (the engagement pressure-the release pressure).

When 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 due to the control pressure acting from the opposite side, the second spool 44b is positioned on the right side in the drawing, and the second spool 44b is released from the intermediate line 50. The state of communication with the line 42 is cut off, and the lock-up clutch 17 is released by the engagement pressure supplied to the engagement chamber 19a as described above.
Is completely fastened.

In other words, in this embodiment, a differential pressure varying with the characteristic shown in FIG. 5 is obtained with respect to the duty ratio output to the duty solenoid valve 47. The lock-up clutch 17 is completely engaged in the range X, and the slip-up control of the lock-up clutch 17 is performed in the range Y.

By the way, during the slip control, the engagement pressure and the release pressure are supplied 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, respectively. The first feedback line 59 for feedback-inputting the engagement pressure is to be input as feedback.
However, the lock-up shift valve 44 is connected to the fastening line 41 that supplies the fastening pressure to the fastening chamber 19a that supplies a large amount of hydraulic oil.
By branching further downstream, the pressure fed back to the control valve 45 reflects the pressure in the engagement chamber, and the lock-up clutch 17
Is performed satisfactorily.

When the ON-OFF solenoid valve 46 is turned OFF, the first and second spools 44a, 44a, 4
4b are located on the left side, and the middle line 5
On the other hand, the communication state between the converter line 48 and the fastening line 41 is interrupted while the 0 communicates with the release line 42. As a result, the lock-up clutch 17 is completely released.

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 lock-up shift valve 44 as shown by a chain line in the figure. Good. Then, the slip control of the lock-up clutch 17 is performed more favorably.

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

[0049]

As described above, according to the present invention, in an automatic transmission in which a pressure regulating valve is arranged upstream of a shift valve that supplies and discharges hydraulic pressure supplied to a hydraulically operated 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 is avoided.

In particular, according to the second aspect of the present invention, the fluid coupling for transmitting the engine output to the speed change mechanism is provided with the lock-up clutch 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 between 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 release valve arranged upstream of the shift valve for engagement with the release pressure. In an automatic transmission provided with a pressure regulating valve for adjusting the differential pressure between the lockup clutch and the chamber, the above-described operation can be obtained when the slip control of the lockup clutch is performed. As a result, the slip control is accurately performed.

[Brief description of the 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 lock-up control portion.

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

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

[Explanation of symbols]

 Reference Signs List 10 Torque converter 17 Lock-up clutch 19a Fastening chamber 19b Release chamber 20 Main transmission 30 Sub-transmission 40 Hydraulic circuit 41 Fastening line 44 Lock-up shift valve 45 Control valve 59 First feedback line

Claims (2)

(57) [Claims] 1. A shift circuit for switching supply and discharge of operating oil pressure to a hydraulic circuit for supplying operating oil pressure to a hydraulically operated actuator, and a shift valve disposed upstream of the shift valve.
An automatic transmission provided with a pressure regulating valve for feedback-controlling the operating oil pressure supplied to the actuator via the shift valve, wherein a feedback passage for feedback input to the pressure regulating valve is provided by the shift valve. A hydraulic control device for an automatic transmission, wherein the hydraulic control device is also branched from a downstream side. 2. A hydraulic coupling for transmitting an engine output to a speed change mechanism, a lock-up clutch directly connected to an input side and an output side is provided, and a lock-up clutch is connected to a hydraulic circuit for supplying control hydraulic pressure to the lock-up clutch. A shift valve for switching 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 a shift valve disposed upstream of the shift valve for adjusting a differential pressure between the release pressure and the engagement chamber. An automatic transmission provided with a pressure regulating valve that performs the automatic transmission, wherein a feedback passage that is fed back to the pressure regulating valve is branched from at least a fastening chamber side passage downstream of the shift valve. Machine hydraulic control device.