JPH0634037A - Engagement force controller for fluid coupling - Google Patents

Abstract

(57) [Summary] (Modified) [Purpose] In an automatic transmission equipped with a fluid coupling in which the engagement force of the lockup clutch is controlled by the pressure regulating valve 45, when the pressure regulating valve 45 is in the exhaust pressure state (shown). Ensure proper lubrication oil even when sticking. A port 44d for connecting a converter line 48 to which a line pressure is supplied to a lock-up shift valve 44 for switching supply and discharge of hydraulic pressure to a fastening chamber 19a and a release chamber 19b of a lock-up clutch 17 and a pressure regulating valve 45. 44g leading to the release chamber on the downstream side of the
And a port 44e for the bypass line. Further, the drain line 49 connected to the drain port 45b of the pressure regulating valve 45 is connected to the bypass valve 63 used at the time of shifting, and the drain line 49 is shut off when the lockup is released.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fastening force control device for a fluid coupling such as a torque converter having a lockup clutch.

[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 discharges a fastening pressure supplied to a fastening chamber for engaging the lockup clutch. And a shift valve having two spools for switching between supply and discharge of the release pressure supplied to the release chamber for releasing the engaged state, and fastening by adjusting the release pressure supplied to the release chamber via the shift valve. A pressure regulating valve for adjusting the pressure difference with the pressure, and
When the two spools shift to one side, the fastening pressure is introduced only in the fastening chamber to engage the lockup clutch,
When both spools shift to the other side, release pressure is introduced only into the release chamber to release the lockup clutch, and when the spools shift to the opposite side so as to be separated from each other, the pressure adjusting valve adjusts them. The configuration is shown in which the lockup clutch is slip controlled by the engaging force corresponding to the differential pressure between the released pressure and the engaging pressure.

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. The output port communicates with the input port when the differential pressure between the release pressure and the engagement pressure is smaller than a predetermined value, and the output port is drain port when the differential pressure becomes larger than the predetermined value. The pressure difference between the release pressure and the fastening pressure is maintained in a constant state by communicating with.

[0006]

By the way, in the above hydraulic circuit structure, the spool of the pressure regulating valve may become stuck during the slip control of the lockup clutch, and the drain port may be opened. If the spool sticks in the closed state, the following problems may occur.

That is, in the lockup released state, the supply of the fastening pressure to the fastening chamber in the torque converter is cut off, and the release pressure is supplied only to the release chamber. Then, the hydraulic oil discharged from the release chamber through the fastening chamber is supplied to each part as lubricating oil. In this case, if the spool of the pressure regulating valve sticks with the drain port opened, hydraulic oil will leak through the drain port, and the amount of hydraulic oil supplied to the torque converter will decrease accordingly. The amount of lubricating oil will be insufficient.

The present invention addresses the above problem in a fluid coupling in which the engagement force of a lockup clutch is controlled by a pressure regulating valve. Even when the pressure regulating valve sticks in the exhaust pressure state, the amount of lubricating oil is increased. The purpose is to ensure.

[0009]

Specifically, a fastening force control device for a fluid coupling according to claim 1 of the present application (hereinafter referred to as the first invention) is a lockup clutch for directly connecting an input side and an output side of the fluid coupling. A shift valve for switching between supply and discharge of the engagement pressure supplied to the engagement chamber for engaging the lock-up clutch and the release pressure supplied to the release chamber for releasing the engaged state, to a hydraulic circuit for supplying the control oil pressure to the shift valve; A lockup state in which a pressure adjusting valve that adjusts the differential pressure from the engagement pressure by adjusting the release pressure supplied to the release chamber via the valve is introduced, and the engagement pressure is introduced only into the engagement chamber. , The lockup release state in which the release pressure is introduced only into the release chamber, and the engagement force of the lockup clutch is controlled according to the pressure difference between the release pressure and the engagement pressure adjusted by the pressure regulating valve. In a fluid coupling configured to achieve a close-up slip state, a bypass passage that bypasses the pressure regulating valve and connects the source pressure side passage to the release chamber, and an opening / closing means that opens the bypass passage when releasing the lockup. Similarly, there is provided an exhaust pressure blocking means for blocking exhaust pressure from the exhaust port of the pressure regulating valve when the lockup is released.

Further, the fastening force control device for a fluid coupling according to claim 2 of the present application (hereinafter referred to as the second invention) is the above-mentioned first aspect.
In the configuration of the invention, the opening / closing means is provided in the shift valve for lockup control.

According to a third aspect of the present invention (hereinafter, referred to as a third invention), a fluid coupling fastening force control device controls the exhaust pressure blocking means at a timing different from lockup in the configuration of the first invention. It is characterized in that it is provided in another valve.

Further, a fastening force control device for a fluid coupling according to claim 4 of the present application (hereinafter, referred to as a fourth invention) is the above-mentioned third aspect.
In the configuration of the invention, by controlling the pilot pressure of the pressure regulating valve by duty, the other valve is controlled by the duty solenoid valve that changes the differential pressure between the release pressure and the engagement pressure adjusted by the pressure regulating valve. It is characterized by being configured.

On the other hand, a fastening force control device for a fluid coupling according to a fifth aspect of the present invention (hereinafter referred to as the fifth invention) has the exhaust pressure blocking means as a shift valve for lockup control in the configuration of the first invention. It is characterized by being provided.

[0014]

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

That is, in any of the first to fifth inventions, in the lock-up slip state, the release pressure adjusted to a constant differential pressure state with respect to the engagement pressure by the pressure regulating valve is released via the shift valve. Since it is supplied to the chamber, the lockup clutch is slip-controlled with a desired engagement force.

In the lockup released state, the exhaust pressure from the pressure regulating valve is blocked, and the working oil in the source pressure side passage bypasses the pressure regulating valve and is supplied to the release chamber. Even if the pressure regulating valve sticks in the exhaust pressure state, a sufficient amount of lubricating oil is secured.

According to the second aspect of the invention, since the bypass passage bypassing the pressure regulating valve is opened / closed by the lockup control shift valve, a special valve for opening / closing the bypass passage is provided. This eliminates the need for a class and simplifies the structure of the hydraulic circuit.

According to the third aspect of the invention, another valve controlled at a timing different from lock-up, for example, a bypass valve used for bypassing the engagement pressure of the friction element at the time of gear shifting is used as a pressure regulating valve. Since the exhaust pressure is blocked, the configuration of the hydraulic circuit is simplified in this case as well.

Further, according to the fourth aspect of the invention, in the third aspect of the invention, the operation of the other valve that blocks the exhaust pressure of the pressure regulating valve is controlled by the duty solenoid valve that controls the duty of the pressure regulating valve. Because
The configuration of the hydraulic circuit will be further simplified.

On the other hand, according to the fifth aspect of the invention, since the shift valve for lockup control prevents the exhaust pressure of the pressure regulating valve, the structure of the hydraulic circuit can be simplified in this case as well. become.

[0021]

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 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 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 deceleration 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 and one reverse gears, 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 summarizes 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.

[0034]

[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 a fastening chamber) 19a on the turbine side and a lock-up release chamber (hereinafter referred to as a release chamber) 19b on the converter cover side, and communicates with each other at an upper portion thereof.

The hydraulic pressure supplied from the hydraulic circuit 40 to the engagement chamber 19a via the engagement line 41 is the damper piston 1
The lockup fastening pressure acts in the direction of pressing 9b against the friction plate, and the hydraulic pressure supplied to the release chamber 19b via the release line 42 acts in the direction of separating the damper piston 19b from the friction plate. It is the release pressure for release. 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.

Here, when the duty ratio D 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. Then, when the duty ratio D 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. Further, a branch line 55 branched from the first control line 52 is connected to the left end side of the second spool 44b, and the first and second spools 44 are also provided.
A constant pressure line 56 that guides a line pressure adjusted to a constant pressure is connected to an intermediate portion between a and 44b.

The lock-up shift valve 4
4, a first input port 44d to which the converter line 48 is connected, a second input port 44e to which an intermediate line 50 from the control valve 45 is connected, and a connection leading to the engagement chamber 19a of the lockup clutch 17. A first output port 44f connected to the line 41 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 arranged in the drawing. When located on the right side, the first input port 44d and the first output port 44f communicate with each other, and when the second spool 44b is located on the left side in the drawing, the second input port 44e and the second output port 44e. It is designed to communicate with 44g.

A pressure holding valve 57 is installed on the drain line 43 connected to the engagement chamber 19a of the lock-up clutch 17 in the torque converter 10 so as to be kept in an integrated 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.

In this embodiment, the lock-up shift valve 44 has a bypass port communicating with the converter line 48 via the first input port 44d when the first spool 44a is located on the left side in the drawing. And a bypass line 59 branched from the intermediate line 50 from the control valve 45 is connected to the bypass port.

A first feedback line 60, which is branched from the fastening line 41, is connected to a first feedback port 45f formed on the left side of the drain port 45b of the control valve 45. Together with the input port 45a of the valve 45
A second feedback line 61 branched from the release line 42 is connected to the second feedback port 45g formed on the right side of the second feedback port 45g. A back pressure line 62 branched from the second control line 54 is connected to the left end side of the control valve 45.

The drain line 49 connected to the drain port 45b of the control valve 45 is connected to the communication port 63a provided in the bypass valve 63 for bypass control of the forward clutch 23.

The bypass 63 is installed on 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 is connected on the upstream side of 5, 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. The bypass port 63c is provided, and the spool 63e moves according to the control pressure introduced into the control port 63d at one end through the line branched from the branch line 55. The output side bypass ports 63b and 63c are shut off, and the drain line 49 from the control valve 45 is connected to the communication port 63.
the state of communicating with the drain port 63f via a,
The output side bypass ports 63b and 63c are communicated with each other and the drain line 49 is cut off.

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 the automatic transmission 1, as shown in FIG. 4, the solenoid valves 46 and 47 for the lockup control and various solenoid valves 69 ...
A controller 100 for controlling the solenoid valve 9 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.

In the above-described structure, as shown in FIG. 3, the ON-OFF solenoid valve 46 is turned ON, and the control port 44a of the lock-up shift valve 44 is turned on.
The control pressure is discharged from the first spool 44.
It is assumed that a is located on the right side of the drawing. At this time, the converter line 48 communicates with the engagement line 41, and the engagement pressure is supplied to the engagement chamber 19a of the lockup clutch 17.

In this state, the duty solenoid valve 47 is connected to the back pressure port of the lockup shift valve 44 and the control port 63d of the bypass bypass 63.
Assuming that a predetermined control pressure adjusted by is supplied to the spool 6 in the bypass bypass 63.
3e is located on the left side of the drawing as shown, and the drain line 49 from the control valve 45 is connected to the drain port 63.
It will communicate with f. On the other hand, in the lock-up shift valve 44, the pressing force acting from one side of the second spool 44b by the line pressure introduced through the constant pressure line 56 is combined with the pressing force due to the control pressure acting from the other side and the spring pressing force. Second when you overcome the total strength of
Since the spool 44b is located on the left side in the drawing, the intermediate line 50 from the control valve 45 communicates with the release line 42.

In this way, the lockup shift valve 44
When the first and second spools 44a and 44b in the above shift in the opposite directions, 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. The line pressure is directly introduced into the engagement chamber 19a via the converter line 48 and the engagement line 41, so that the lockup clutch 17 operates according to the pressure difference between them (the engagement pressure-the release pressure). It will be slip controlled.

Then, if the control pressure is further increased from this state, the lockup shift valve 4 is brought to a predetermined pressure state.
The second spool 44b of No. 4 moves to the right in the drawing against the pressing force by the constant pressure, and the intermediate line 5
The communication state between 0 and the release line 42 is cut off, and the lockup clutch 17 is completely engaged by the engagement pressure supplied to the engagement chamber 19a as described above.

On the other hand, when the control pressure decreases to a predetermined value or less, the spool 63e moves rightward in the drawing in the bypass bypass 63, and the drain line 49 from the control valve 45 is connected. The communication between the port 63a and the drain port 63f is cut off,
Along with this, the back pressure of the control valve 45 is blocked.

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

On the other hand, when the ON-OFF solenoid valve 46 is turned OFF, as shown in FIG.
Since the spools 44a and 44b are both positioned on the left side, the communication state between the converter line 48 and the fastening line 41 is blocked while the intermediate line 50 communicates with the release line 42, whereby the lockup clutch 1
7 is completely released. At this time, the first input port 44d connected to the converter line 48 and the bypass port connected to the bypass line 44d communicating with the intermediate line 50 communicate with each other.

Here, since the shift control is performed with the lockup clutch 17 being released as described above, the control of the release pressure by the control valve 45 becomes unnecessary. Therefore, even if the discharge of the hydraulic oil from the drain line 49 connected to the drain port 45b of the control valve 45 is stopped, the operation of the lockup clutch 17 released as described above is not affected at all. By using the duty solenoid valve 47 and the bypass bypass 63, it is possible to perform bypass control of the engagement pressure supply operation for the friction element.

That is, the duty solenoid valve 47
When the spool 63e is positioned on the right side in the drawing by completely exhausting the control port 63d of the bypass bypass 63 as shown in FIG. The branched upstream line 66 and the downstream line 67 that joins the forward line downstream of the orifice 65 are connected to the bypass bypass 63 and the output side bypass port 63.
It will be connected via b and 63c. Therefore,
For example, when selecting from a non-forward range such as N range to a forward range such as D range, the forward line 64
When the fastening pressure is supplied to the forward clutch 23 by
This fastening pressure is quickly supplied to the forward clutch 23 without passing through the orifice 65 on the forward line 64, and the forward clutch 23 is fastened without delay.

Further, by setting the duty ratio output to the duty solenoid valve 47 to 100 when the lockup clutch 17 is released, the spool 63e of the bypass bypass 63 is also rightward in the drawing as shown in FIG. 7 in this case as well. Therefore, the back pressure from the control valve 45 is blocked. Therefore, even if the spool 45e of the control valve 45 sticks in the state where the drain port 45b is opened as shown in the figure, the hydraulic oil is prevented from leaking and the hydraulic oil supplied to the release chamber 19b is not supplied to the fastening chamber 19a.
And is supplied as lubricating oil through the drain line 43. In this case, even if it is necessary to move the spool 63e of the bypass bypass 63 to the left side in the drawing at the time of shifting, the converter line 48 and the intermediate line 50 are communicated via the bypass line 59. Therefore, the operating oil is surely introduced into the release chamber 19b, and the lubricating oil does not run short.

Next, a second embodiment of the present invention will be described.

In the second embodiment, as shown in FIG. 8, the first lockup shift valve 44 is provided with the first lockup shift valve 44.
The first input port 44d is connected to the fastening line 41.
The output port 44f and the bypass port 44f connected to the bypass line 70 branched from the release line 42 leading to the release chamber 19b are configured to be selectively communicable with each other, and 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 the communication port 44h provided so as to communicate with the drain port in the state of being located at. The branch line 5 branched from the first control line 52 in which the control pressure adjusted by the duty solenoid valve 47 is generated in the intermediate portion between the first spool 44a and the second spool 44b.
5 is connected.

In this embodiment, the first feedback port 45f formed on the right side of the drain port 45b of the control valve 45 has a first feedback line 60 branched from the fastening line 41. Is connected and the valve 45
A second feedback line 61 branched from the intermediate line 50 on the upstream side of the lockup shift valve 44 is connected to the second feedback port 45g formed on the left side of the input port 45a. .

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 lock-up shift valve 44 is discharged, and 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. 8, 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 shift valve 44 overcomes the pressing force by the control pressure, the second spool 44b is positioned on the right side in the drawing, and the intermediate line 50 and the release line 42 are separated from each other. Communication is cut off,
As described above, the lockup clutch is completely engaged by the engagement pressure supplied to the engagement chamber 19a.

That is, in this embodiment, a differential pressure varying with the characteristic shown in FIG. 9 is obtained with respect to the duty ratio D output to the duty solenoid valve 47. The lockup clutch is completely engaged in the range of region X ', and the lockup clutch is slip-controlled in the range of region Y'.

On the other hand, when the ON-OFF solenoid valve 46 is turned off, as shown in FIG.
Since the spools 44a and 44b are both positioned on the left side, the communication state between the converter line 48 and the fastening line 41 is blocked while the intermediate line 50 communicates with the release line 42, whereby the lockup clutch 1
7 is completely released. At this time, the drain line 49 from the control valve 45 was connected while the first input port 44d to which the converter line 48 was connected and the bypass port to which the bypass line 70 leading to the release line 42 were connected. The communication state between the communication port 44h and the drain port is blocked, and the back pressure of the control valve 45 is blocked. Therefore, as shown in the figure, the control valve 45
Even if the spool e is stuck in a state of communicating with the drain port 45b, the hydraulic oil is prevented from leaking and the hydraulic oil supplied to the release chamber 19b is used as lubricating oil via the fastening chamber 19a and the drain line 43. Will be supplied.

In this embodiment, unlike the first embodiment, the control pressure generated by the ON-OFF solenoid valve 46 is not introduced to the left end side of the control valve 45. Therefore, ON-OFF
The residual pressure generated when the solenoid valve 46 is turned off has no influence, and good pressure regulation characteristics can be obtained.

[0066]

As described above, according to the present invention, in the lock-up slip state, the release pressure adjusted by the pressure regulating valve to a constant differential pressure state with respect to the engagement pressure is released through the shift valve to the release chamber. Therefore, the lockup clutch is slip-controlled with a desired engagement force.

In the lockup released state, the exhaust pressure from the pressure regulating valve is blocked and the working oil in the source pressure side passage bypasses the pressure regulating valve and is supplied to the release chamber. Even if the pressure regulating valve sticks in the exhaust pressure state, a sufficient amount of lubricating oil is secured.

According to the second aspect of the invention, since the bypass passage bypassing the pressure regulating valve is opened / closed by the lockup control shift valve, a special valve for opening / closing the bypass passage is provided. This eliminates the need for a class and simplifies the structure of the hydraulic circuit.

Further, according to the third aspect of the invention, since the other valve which is controlled at a timing different from the lock-up is used to prevent the exhaust pressure of the pressure regulating valve, the construction of the hydraulic circuit is also possible in this case. Will be simplified.

Further, according to the fourth aspect of the present invention, in the third aspect of the invention, the operation of the other valve that blocks the exhaust pressure of the pressure regulating valve is controlled by the duty solenoid valve that controls the duty of the pressure regulating valve. Because
The configuration of the hydraulic circuit will be further simplified.

On the other hand, according to the fifth aspect of the invention, since the shift valve for lockup control prevents the pressure relief valve from exhausting pressure, the construction of the hydraulic circuit can be simplified in this case as well. become.

[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 in the first embodiment.

FIG. 6 is a hydraulic circuit diagram showing a lockup released state.

FIG. 7 is a hydraulic circuit diagram showing a state where the control valve is stuck.

FIG. 8 is a hydraulic circuit diagram of a lockup control portion in the second embodiment.

FIG. 9 is a differential pressure characteristic diagram with respect to a duty ratio in the second embodiment.

FIG. 10 is a hydraulic circuit diagram showing a state where the control valve is stuck in the second embodiment.

[Explanation of symbols]

 10 Torque Converter 17 Lockup Clutch 40 Hydraulic Circuit 44 Lockup Shift Valve 41 First Spool 45 Control Valve 47 Duty Solenoid Valve 59 Bypass Line 45b Drain Port 63 Bypass Valve

Claims (5)

[Claims] 1. A hydraulic circuit for supplying a control hydraulic pressure to a lock-up clutch that directly connects an input side and an output side of a fluid coupling releases a fastening pressure and a fastening state supplied to a fastening chamber for fastening the lock-up clutch. A shift valve for switching supply and discharge of the release pressure supplied to the release chamber, and a pressure adjusting valve for adjusting the pressure difference between the engagement pressure and the release pressure by adjusting the release pressure supplied to the release chamber via the shift valve. Is provided, the lockup state in which the fastening pressure is introduced only into the fastening chamber, the lockup release state in which the release pressure is introduced only into the release chamber, and the release pressure and the fastening pressure adjusted by the pressure regulating valve. In a fluid coupling configured to achieve a lock-up slip state in which the engagement force of the lock-up clutch is controlled according to the differential pressure between A bypass passage that connects the source pressure side passage to the release chamber, an opening / closing means that opens the bypass passage when the lockup is released, and a discharge pressure blocking that blocks discharge pressure from the discharge port of the pressure regulating valve when the lockup is released. And a means for controlling the fastening force of the fluid coupling. 2. The fastening force control device for a fluid coupling according to claim 1, wherein the opening / closing means is provided in a shift valve for lockup control. 3. The fastening force control device for a fluid coupling according to claim 1, wherein the exhaust pressure blocking means is provided in another valve that is controlled at a timing different from the lockup. 4. A duty solenoid valve for controlling another valve by duty-controlling a pilot pressure of a pressure regulating valve so as to change a differential pressure between a release pressure and a fastening pressure regulated by the pressure regulating valve. The fastening force control device for a fluid coupling according to claim 3, wherein 5. The exhaust pressure prevention means is provided in a shift valve for lock-up control.
A fastening force control device for a fluid coupling according to item 1.