JPH084891A - Lockup clutch control device - Google Patents

Abstract

PURPOSE:To surely prevent dragging of a lockup clutch in an area where consumption/supplement balance is severe. CONSTITUTION:A changeover valve 70 is arranged between a torque converter relief valve 60 and a third oil passage 93, for changing over an oil passage based on a pressure balance of torque converter relief pressure and pilot pressure of a hydraulic actuator 40. When the torque converter relief pressure is a specified value or more, drain pressure is supplied to a lockup clutch releasing chamber 18 through the changeover valve 70, the third oil passage 93, a lockup control valve 50, and a second oil passage 92. When the torque converter relief pressure is less than the specified value, the pilot pressure is supplied to the lockup clutch releasing chamber 18 through an oil passage 84, the changeover valve 70, the third oil passage 93, the lockup control valve 50, and the second oil passage 92.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a lockup clutch control device in a lockup clutch mechanism torque converter.

[0002]

2. Description of the Related Art A torque converter not only operates as an automatic clutch but also has an effect of increasing torque, and is usually connected to an automatic transmission to form an automatic transmission.

FIG. 6 is a schematic configuration diagram of a conventional general torque converter and lockup clutch control device.
The torque converter 10 includes an impeller called a pump impeller 11 as an input element, an impeller called a turbine runner 12 as an output element, and an impeller called a stator 13 arranged between them.

The pump impeller 11 is a torque converter cover 1 which is rotated by the crankshaft of the engine.
4 and is rotationally driven. The turbine runner 12 is connected to an input shaft of an automatic transmission (not shown). The stator 13 is attached to the input shaft via a so-called one-wake clutch so as to be able to rotate idly. Then, the inside of the torque converter 10 is filled with hydraulic oil.

When the engine rotates, the torque converter cover 14 and the pump impeller 11 rotate, and the working oil in the pump impeller flows toward the outer periphery by the centrifugal force, passes through the turbine runner 12 and the stator 13, and again the pump impeller 11. Circulate to. This flow causes the turbine runner 12 to rotate and be transmitted to the input shaft of the automatic transmission.

Since the torque converter 10 uses hydraulic oil as a medium for power transmission, the loss due to slippage is large and the power transmission efficiency is about 10% lower than that of a mechanical clutch. Therefore, a torque converter including a lock-up clutch 15 that mechanically directly connects the torque converter cover 14 to the input shaft of the automatic transmission when the vehicle speed exceeds a certain speed has become common.

The lock-up clutch 15 includes a lock-up piston 17 on a turbine hub 16 attached to an input shaft.
7 includes a clutch facing 17a facing the inner surface of the torque converter cover 14.

A lockup clutch release chamber 18 on the side of the torque converter cover 14 and a torque converter chamber 19 on the opposite side are arranged with the lockup piston 17 as a boundary. A release pressure acting in a direction of separating the lockup piston 17 from the torque converter cover 14 is applied, and an engagement pressure acting in a direction of engaging the lockup piston 17 with the torque converter cover 14 by the hydraulic oil is applied to the torque converter chamber 19. Is added.

Normally, the lockup clutch 15 is controlled by the lockup control valve 50. That is, in the lock-up clutch release chamber 18, the oil drained from the drain port 21 of the pressure regulator valve 20 when the oil discharged from the oil pump 1 is regulated to the line pressure by the pressure regulator valve 20 is relieved by the torque converter relief. It is supplied via the valve 60 and the lockup control valve 50 (the hydraulic pressure generated at this time becomes the torque converter relief pressure).

On the other hand, the torque converter chamber 19 is supplied with hydraulic oil whose pressure is regulated by the pilot valve 30 and the hydraulic actuator 40 using the line pressure as a source pressure via the lockup control valve 50.

The lock-up control valve 50 discharges the hydraulic oil from the lock-up clutch release chamber 18 and supplies the hydraulic oil into the torque converter chamber 19 so that the engagement pressure becomes larger than the release pressure, and the lock-up occurs. The clutch 15 is engaged. On the contrary, the lockup control valve 50 supplies the hydraulic oil into the lockup clutch release chamber 18 and discharges the hydraulic oil from the torque converter chamber 19, so that the release pressure becomes larger than the engagement pressure, and the lockup The up clutch 15 is released.

By the way, when the lockup clutch 15 is not completely released from the torque converter cover 14 (hereinafter referred to as dragging of the lockup clutch 15) when the engine is idle, engine stall occurs. It is necessary to surely release the lockup clutch 15. For that purpose, it is necessary to supply the lock-up clutch release chamber 18 with an oil flow rate (hydraulic pressure) sufficient to prevent the lock-up clutch 15 from being dragged.

However, in a region where the engine speed is high and the engine speed is low (especially when the engine is idling), the oil pump 1 discharges a small amount of oil, and the amount of oil consumed from each part of the automatic transmission (including the leakage flow rate). Since it will increase compared to the normal temperature range, the oil balance will be severe.

In such a region, the line pressure itself becomes lower than the set pressure adjustment value, so that the pressure regulator valve 20 is almost completely closed. As a result, the normal running condition is that the oil is not drained to the drain port 21 of the pressure regulator valve 20.
The amount of oil supplied to the lock-up clutch release chamber 18 is reduced compared to when the environmental conditions are increased, and the lock-up clutch 15 may be dragged.

Therefore, when the torque converter release pressure falls below the hydraulic pressure that causes drag of the lockup clutch 15, the switching valve switches the oil passage,
It has been devised that the pilot pressure, which is the output pressure of the pilot valve 30, is introduced into the lock-up clutch release chamber 18 to prevent the lock-up clutch 15 from being dragged at a high temperature and a low engine speed. It was

As a conventional technique for surely releasing the lock-up clutch 15 by using the switching valve in this way, for example, it is disclosed in Japanese Patent Application Laid-Open Nos. 1-248553 and 60-143264. There was something that was done.

Although not a known example, a method called bypass orifice tuning is also considered as a method not using a switching valve. This is because the line pressure circuit 80 and the torque converter release pressure circuit 82 are connected by the bypass circuit 4 having the orifice 3 as shown by the chain double-dashed line in FIG. 6, and the drag amount of the lockup clutch 15 does not occur. Is to ensure.

[0018]

However, in the device disclosed in Japanese Unexamined Patent Publication No. 1-247853,
When switching the switching valve oil passage, the drain port of the hydraulic actuator (solenoid) is used, and there is a problem that the cost becomes high.

Further, in the apparatus disclosed in Japanese Patent Laid-Open No. 60-143264, three switching valves are required to operate the switching valves, and there is a problem that the circuit structure becomes complicated and the cost becomes high. .

In the case of the bypass orifice tuning method, there is a problem that it is difficult to balance the flow rate between the line pressure circuit 80 and the torque converter release pressure circuit 82.

For example, it is difficult to respond to a request for lowering the engine idle speed. More specifically, as the idling speed decreases, the oil amount balance becomes more severe, so that the environment in which the drag of the lockup clutch 15 is more likely to occur is created. If the throttle diameter of the orifice 3 is enlarged in order to prevent this, the flow rate of the orifice 3 increases as the line pressure increases, resulting in a decrease in the line pressure. Therefore, in order to achieve both the drag prevention of the lockup clutch 15 and the line pressure reduction prevention, it is necessary to set the throttle diameter of the orifice 3 by trial and error including experimental confirmation, but this is an extremely difficult operation. Is.
And if there is no compatible solution, then another measure for improving oil balance should be incorporated.

The present invention has been made in view of the above problems of the prior art, and lockup clutch hydraulic control capable of reliably preventing drag of the lockup clutch in a region where the oil amount balance is severe. It is a first object to provide a device.

A second object of the present invention is to provide a lock-up clutch hydraulic control device capable of solving the first problem with an extremely simple hydraulic circuit configuration.

[0024]

[Means for Solving the Problems]

[1] In order to solve the first problem, the present invention provides
A torque converter chamber 19 and a lockup clutch disengagement chamber provided with a lockup piston 17 as a boundary between which a pump impeller 11 side that rotates with the output shaft of the engine and a turbine runner 12 side that rotates with the input shaft of the automatic transmission can be fastened. 18, a lockup control valve 50 that is operated by electrically driving a hydraulic actuator 40, and a first liquid passage 9 that connects the lockup control valve 50 with the torque converter chamber 19 and the lockup clutch release chamber 18.
1 and a second liquid passage 92, and the first liquid passage 91 and
Alternatively, hydraulic fluid is supplied from the lockup control valve 50 via the second hydraulic passage 92, and the hydraulic pressure in the torque converter chamber 19 and the hydraulic pressure in the lockup clutch release chamber 18 are controlled by driving the hydraulic actuator 40. Then, move the lockup piston 17 to move the lockup clutch 15
In the lockup clutch control device for engaging and disengaging the lockup clutch 15, the third fluid passage 93 for supplying the first fluid pressure into the lockup clutch release chamber 18 when the lockup clutch 15 is released is connected, and The lockup clutch control device is characterized in that when the hydraulic pressure of 1 is insufficient, a second hydraulic pressure higher than the first hydraulic pressure is supplied from the third hydraulic passage 93 (claim 1). Correspondence).

[2] In order to solve the second problem of the present invention, in the structure of [1], the third liquid passage 93 is provided with the second liquid passage 93 via the lock-up control valve 50.
The switching valve 70 is connected to the fluid passage 92, and the switching valve 70 is inserted in the third fluid passage, and the lockup control valve 50 opens the first fluid passage 91 by the fluid pressure from the fluid pressure actuator 40. When the hydraulic pressure in the converter chamber 19 is released from the passage 91, the third hydraulic passage 93 and the second hydraulic passage 92 are connected to each other, and the switching valve 70 is operated by the source pressure of the hydraulic actuator 40. The passage 93 is opened to supply the first hydraulic pressure from the hydraulic pressure source from the third hydraulic passage 93 to the lockup clutch release chamber 18 via the second hydraulic passage 92, and the switching valve 70
Is when the first hydraulic pressure becomes lower than a predetermined pressure value,
The switching valve 70 causes the hydraulic pressure from the hydraulic actuator 40 to be the second hydraulic pressure, and the lockup clutch release chamber 18 passes from the third hydraulic passage 93 to the second hydraulic passage 92.
The lock-up clutch control device is characterized in that the lock-up clutch control device is supplied to the device (corresponding to claim 2).

[0026]

According to the constitution [1] of the present invention, when the lockup clutch 15 is disengaged and the first hydraulic pressure becomes insufficient due to a severe liquid amount balance, the first hydraulic pressure is lower than the first hydraulic pressure. A high second hydraulic pressure is supplied to the lockup clutch release chamber 18 via the third hydraulic passage 93, and as a result, the hydraulic pressure in the lockup clutch release chamber becomes larger than the pressure in the torque converter chamber, and the lockup clutch is released. Is surely released.

According to the constitution [2] of the present invention, the first
If the hydraulic pressure of the first hydraulic pressure exceeds the predetermined pressure value, the switching valve 70 causes the first hydraulic pressure to flow from the third hydraulic fluid path 93 to the second hydraulic fluid path 9
It is supplied to the lock-up clutch release chamber 18 via 2. On the other hand, when the first hydraulic pressure becomes equal to or lower than the predetermined pressure value, the switching valve 70 causes the second hydraulic pressure to pass from the third hydraulic fluid passage 93 to the second hydraulic fluid passage 92 through the lockup clutch release chamber 18. Is supplied to.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 3 are hydraulic control circuit diagrams of a lockup clutch control device according to the present invention.

<Structure of Torque Converter> Since the torque converter 10 has the same structure as the conventional one,
The same reference numerals are given to the same aspect parts and the description thereof will be omitted.

<Structure of Hydraulic Control Circuit>
An oil pump 1, an oil cooler 2, a pressure regulator valve 20, a pilot valve 30, a hydraulic actuator 40, a lockup control valve 50, a torque converter relief valve 60, and a switching valve 70 are provided.

The oil discharged from the oil pump 1 is regulated by the pressure regulator valve 20, and then the oil passage 8
0 acts as line pressure on each engagement element (here, the oil passage configuration up to each engagement element is omitted) excluding the lockup clutch 15.

The oil drained from the drain port 21 of the pressure regulator valve 20 at the stage of pressure regulation by the pressure regulator valve 20 is supplied to the input port 61 of the torque converter relief valve 60 via the oil passage 81.

The torque converter relief valve 60 has both a pressure adjusting function of adjusting the hydraulic pressure from the oil passage 81 to the torque converter release pressure (first hydraulic pressure) and a function of preventing the torque converter cover 14 from being destroyed by the excessive hydraulic pressure. . That is, the torque converter cover 14 is prevented from being deformed,
When the hydraulic pressure above the allowable pressure is sent to the torque converter relief valve 60 via the oil passage 81, the pressure is reduced below the allowable pressure.

The oil whose pressure is adjusted to the torque converter relief pressure by the torque converter relief valve 60 is supplied from the output port 62 communicating with the input port 61 to the ports 73 and 74 of the switching valve 70 via the oil passage 82. It

The torque converter release pressure introduced into the port 73 acts as a force for shifting the spool 71 to the left in the drawing together with the spring force of the spring 72 built in the switching valve 70.

Further, the oil whose line pressure is adjusted by the pressure regulator valve 20 is supplied from the oil passage 80 to the pilot valve 3
0, the output pressure of the pilot valve 30 is adjusted to the pilot pressure of the hydraulic actuator 40. This pilot pressure becomes a control pressure for controlling the stroke position of the lockup control valve 50.

The pilot pressure is supplied to the hydraulic actuator 40 via the oil passage 83, and also to the ports 75 and 76 of the switching valve 70 via the oil passage 84 to the second liquid for releasing the lockup clutch 15. Supplied as pressure. The pilot pressure supplied to the port 76 is the spool 7
1 acts as a force to shift 1 to the right in the figure.

Through the oil passage 83, the hydraulic actuator 40
The hydraulic pressure sent to the hydraulic pressure actuator 40 is controlled by the hydraulic pressure actuator 40 to a hydraulic pressure corresponding to each traveling state / environmental state, and then the oil passage 8
5 is supplied to the port 53 of the lockup control valve 50.

The hydraulic actuator 40 is a solenoid driven and controlled by an electronic control unit (ECU) composed of a microcomputer, and is usually called a lockup solenoid. That is, when the electronic control unit ECU changes the duty ratio of the drive voltage applied to the lockup solenoid, the degree of advancement of the movable core of the lockup solenoid changes. As a result, the on / off time of the duty ratio changes, and the flow rate on the output side changes. The longer the duty ratio off time, the more pilot valve 30
Output pressure, that is, the hydraulic pressure to the lockup control valve 4 decreases.

The hydraulic pressure supplied to the port 53 of the lock-up control valve 50 is, together with the spring force of the spring 52 built in the lock-up control valve 50, the spool 5
1 acts as a force to shift 1 to the right in the figure.

<Normal lock-up clutch engaged state>
Then, the output pressure of the hydraulic actuator 40 is controlled to be the minimum in the region where the lockup clutch 15 that is determined by the shift schedule is engaged in each traveling state / environmental state. As shown, the spool 51 of the lockup control valve 50 shifts to the left.

In this state, the torque converter release pressure supplied from the torque converter relief valve 60 is
The third oil passage 93 is provided through the ports 74 and 77 of the switching valve 70.
Via the ports 54, 55 of the lockup control valve 50
Is supplied to the torque converter chamber 19 via the first oil passage 91 and acts as an engagement pressure. At this time, the hydraulic pressure in the lockup clutch release chamber 18 is released to the atmosphere from the second oil passage 92 and the port 56 of the lockup control valve 50 via the drain port 57. As a result, the lockup clutch 15 is engaged.

<Normal lock-up clutch released state>
On the other hand, the output pressure of the hydraulic actuator 40 is controlled to be maximum in the region where the lockup clutch 15 is released, which is determined by the shift schedule. At this time, as shown in FIG. The spool 51 of 50 shifts to the right.

In this state, the second oil passage 92 and the drain port 57 of the lockup control valve 50 are shut off, and the second oil passage 92 and the output port 6 of the torque converter relief valve 60 are closed.
2 is a port 74, 77 in the switching valve 70 and a third oil passage 9
3 and the ports 54 and 56 of the lockup control valve 50. As a result, the torque converter relief pressure supplied from the torque converter relief valve 60 is supplied into the lockup clutch release chamber 18 and acts as a release pressure. Further, the lockup clutch release chamber 18
The oil introduced into the inside passes through the torque converter chamber 19, the first oil passage 91, and the port 5 of the lockup control valve 50.
It flows into the oil cooler 2 through 5, 58, 59 and the oil passage 86. As a result, the lockup clutch 15 is released.

<Mechanism for releasing the lockup clutch> When releasing the lockup clutch 15,
The hydraulic pressure in the lock-up clutch release chamber 18 and the hydraulic pressure in the torque converter chamber 19 should be substantially equal because the resistance between the two chambers is extremely small. However, in reality, the torque converter chamber 19 is affected by the centrifugal oil pressure.
The force acting to bring the lockup clutch 15 closer to the torque converter cover 14 by the hydraulic pressure inside is
The hydraulic pressure in the lock-up clutch release chamber 18 becomes larger than the force that acts to separate the lock-up clutch 15 from the torque converter cover 14, and the lock-up clutch 15 is engaged (slipped) as it is, and the engine load is reduced. There is a possibility that engine stall may occur in the area of.

Therefore, an oil flow is generated from the second oil passage 92 to the torque converter chamber 19 via the lockup clutch release chamber 18, and the lockup clutch release chamber 1
It is necessary to make the hydraulic pressure in 8 higher than the hydraulic pressure in the torque converter chamber 19, prevent the lock-up clutch 15 from dragging, and prevent engine stall.

However, at a high temperature and a low engine speed such as when the engine is idling, the flow rate of the oil consumed increases as compared to the normal temperature range,
Moreover, since the discharge flow rate by the oil pump 1 is reduced,
The oil balance is in a severe area.

At this time, the pressure regulator valve 2
0 is almost completely closed, and there is a possibility that the lockup clutch release chamber 18 cannot be supplied with hydraulic pressure (oil flow rate) sufficient to prevent the lockup clutch 15 from being dragged.

<Switching Operation of Switching Valve> Therefore, in the hydraulic control circuit of this embodiment, the pilot pressure to the hydraulic actuator 40 is locked up via the switching valve 70 in such a severe oil amount balance region. The lockup clutch 15 is supplied to the clutch release chamber 18, so that an oil flow rate (hydraulic pressure) is secured so that the lockup clutch 15 is not dragged. Hereinafter, this will be described in detail.

The shift position of the spool 71 of the switching valve 70 is determined by the force of the output pressure of the torque converter release valve 60, the pilot pressure of the hydraulic actuator 40, and the spring force of the spring 72 of the switching valve 70. .

That is, the shift position of the spool 71 is greatly influenced by the torque converter release pressure characteristic and the pilot pressure characteristic, but in reality, the pilot pressure has little variation with respect to each operating condition and environmental condition, and therefore the shift position is controlled. The key factor is the torque converter release pressure characteristic.

In this switching valve 70, when the output pressure of the torque converter release valve 60 drops below a predetermined set value (that is, the hydraulic pressure value that causes the lock-up clutch drag), the spool 71 is driven by the pilot pressure.
The force that shifts the rightward direction is the output pressure of the torque converter release valve 60 and the spool 7 due to the spring 72.
It is set to exceed the force for shifting 1 to the left.

As a result, the spool 71 shifts to the right as shown in FIG. 1, and the port 75 and the port 77 of the switching valve 70 communicate with each other. Then, the pilot pressure of the oil passage 84 is supplied to the port 54 of the lockup control valve 50 via the ports 75 and 77 and the third oil passage 93, and further,
It is supplied to the lockup clutch release chamber 18 via the port 56 and the second oil passage 92.

This pilot pressure is higher than the output pressure of the torque converter relief valve 60, and has a pressure sufficient to obtain an oil flow rate that prevents the lockup clutch 15 from being dragged. Therefore, the drag of the lockup clutch 15 does not occur even in the region where the oil amount balance is severe as described above.

Explaining the above with reference to the flowchart of FIG. 4, first, it is determined whether the torque converter release pressure is equal to or higher than a predetermined value (step 100). If the torque converter release pressure is equal to or higher than the predetermined value, the switching valve is not switched. (Step 101), the torque converter release pressure flows from the third liquid passage 93 into the torque converter release pressure circuit (step 102). If the torque converter release pressure is less than the predetermined value, the switching valve switches (step 103), and the pilot pressure flows from the third fluid passage 93 into the torque converter release pressure circuit (step 104).

FIG. 5 shows a hydraulic pressure / flow rate characteristic diagram comparing the lockup control device according to the present embodiment with a conventional device.
From this, it can be understood that the control device of the present embodiment can secure the necessary amount of oil for releasing the lock-up clutch 15 while securing the required line pressure even in the low engine speed region. .

As described above, in this hydraulic control device, by introducing the pilot pressure into the switching valve 70, the switching valve 70 is switched, and either the torque converter relief pressure or the pilot pressure is supplied to the lockup clutch release chamber 18. Can supply a new drive source for switching the switching valve 70 required in the past (for example, a hydraulic actuator typified by a solenoid type or other switching valve).
Does not need That is, even though the hydraulic control circuit has a simpler structure than the conventional one, it is possible to reliably prevent the lock-up clutch 15 from being dragged in a region where the oil amount balance is severe.

Further, in this hydraulic control device, a substantially constant hydraulic pressure can be supplied to the lock-up clutch disengagement chamber 18 irrespective of operating conditions / environmental conditions, so that the flow rate consumed increases in accordance with operating conditions / running conditions. There is nothing to do. Therefore, it is possible to downsize the oil pump 1 by the amount that does not need to increase the consumption flow rate.

[0059]

According to the constitution [1] of the present invention, the hydraulic pressure necessary for releasing can be supplied to the lock-up clutch release chamber 18 even in a region where the hydraulic pressure balance is severe, and as a result, the lock can be achieved. It is possible to reliably prevent the up clutch 15 from being dragged.

Further, according to the above-mentioned constitution [2], the lock-up clutch control device of the present invention can be easily realized only by adding the switching valve to the conventional device.

[Brief description of drawings]

FIG. 1 is a hydraulic control circuit diagram showing an embodiment of a lockup clutch control device of the present invention, showing a state in which a second hydraulic pressure is supplied to a lockup clutch release chamber to release a lockup clutch. is there.

FIG. 2 is a hydraulic control circuit diagram showing an embodiment of a lockup clutch control device of the present invention, showing a state in which a first hydraulic pressure is supplied to a lockup clutch release chamber to release the lockup clutch. is there.

FIG. 3 is a hydraulic control circuit diagram showing an embodiment of the lockup clutch control device of the present invention, and is a diagram showing a state in which the first hydraulic pressure is supplied to the torque converter chamber to engage the lockup clutch.

FIG. 4 is a diagram showing an operation flowchart according to the present invention.

FIG. 5 is a hydraulic pressure / flow rate characteristic diagram showing a comparison between the device of the embodiment of the present invention and a conventional device.

FIG. 6 is a hydraulic control circuit diagram in a conventional lockup clutch control device.

[Explanation of symbols]

 10 ... Torque converter, 11 ... Pump impeller, 12 ... Turbine runner, 17 ... Lockup piston, 18 ... Lockup clutch disengagement chamber, 19 ... Torque converter chamber, 20 ... -Pressure regulator valve, 30 ... Pilot valve, 40 ... Hydraulic actuator, 50 ... Lock-up control valve, 60 ... Torque converter relief valve, 70 ... Switching valve, 91 ... No. 1 oil passage (1st liquid passage), 92 ... 2nd oil passage (2nd liquid passage), 93 ... 3rd oil passage (3rd liquid passage).

Claims (2)

[Claims] 1. A lock-up piston (17) which can fasten a pump impeller (11) side rotating with an output shaft of an engine and a turbine runner (12) side rotating with an input shaft of an automatic transmission at a boundary. A torque converter chamber (19) and a lock-up clutch release chamber (18), a lock-up control valve (50) operated by driving an electric hydraulic actuator (40), and the lock-up control valve (50). A first liquid passage (91) and a second liquid passage (92) communicating with the torque converter chamber (19) and the lock-up clutch release chamber (18), and the first liquid passage (91), Alternatively, the hydraulic fluid is supplied from the lockup control valve (50) through the second fluid passage (92), and the hydraulic pressure in the torque converter chamber (19) and the lockup clutch release chamber (18) are increased. By controlling the driving of said hydraulic actuator pressure (40), the lock-up clutch (1 to move the lock-up piston (17)
In the lockup clutch control device for engaging / disengaging the lockup clutch (5), a third fluid passage (93) for supplying a first fluid pressure into the lockup clutch release chamber (18) when the lockup clutch (15) is released. ) Is connected, and when the first hydraulic pressure is insufficient, a second hydraulic pressure higher than the first hydraulic pressure is supplied from the third hydraulic passage (93). Clutch control device. 2. The lockup clutch control device according to claim 1, wherein the third liquid passage (93) is connected to the second liquid passage (92) via the lockup control valve (50). At the same time, the switching valve (70) is inserted in the third liquid passage, and the lockup control valve (50) opens the first liquid passage (91) by the hydraulic pressure from the hydraulic actuator (40). When the hydraulic pressure in the converter chamber (19) is released from the liquid passage (91), the third liquid passage (93) and the second liquid passage (92).
And the switching valve (70) opens the third fluid passage (93) by the source pressure of the fluid pressure actuator (40) to move the first fluid pressure from the fluid pressure source to the third fluid passage ( 93) to the second liquid path (92)
To the lock-up clutch disengagement chamber (18), and the switching valve (70) operates by the switching valve (70) when the first hydraulic pressure becomes lower than a predetermined pressure value. The hydraulic pressure from (40) is used as the second hydraulic pressure, and the third hydraulic passage (93) to the second hydraulic passage (9) are used.
The lock-up clutch control device is characterized in that it is supplied to the lock-up clutch release chamber (18) via 2).