JPH063208Y2 - Direct coupling clutch control device for torque converter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a device for controlling a direct coupling clutch (so-called lock-up clutch) of a torque converter mounted on a wheel type work vehicle such as a rough terrain crane and a wheel loader. It is a thing.

[Conventional technology]

The direct coupling clutch of the torque converter operates based on a command from a computer or the like in order to eliminate loss of power transmission during high-speed traveling, and has a function of directly coupling the engine and the drive wheels.

The performance required when the clutch is operated is (a) from when an operation command is issued until the clutch actually starts to operate, that is, oil is sent into the clutch oil chamber and the clutch plate comes into contact with the torque converter cover (clutch The so-called filling time from the off position to the clutch contact point) is short. (B) After the above contact, there is no shock until the clutch plate is further pressed and the clutch is completely engaged, and smooth engagement operation is performed. There are two points.

The conventional direct-coupling clutch control device has a configuration as shown in FIG. 2 based on such circumstances.

In the figure, 1 is a torque converter, which is a pump 2 incorporated in the torque converter 1 and a direct coupling clutch 3
The hydraulic circuit 4 connecting to the oil chamber is provided with an electromagnetic switching valve 5 which is operated by switching from the shut-off position a to the communication position b by an operation signal from a computer or the like at a vehicle speed above a certain level.
When the electromagnetic switching valve 5 is operated, pump discharge oil is sent to the clutch oil chamber to operate the direct coupling clutch 3.

A pressure regulating valve 6 is connected to the hydraulic circuit 4, and the pressure in the hydraulic circuit 4 is regulated by the pressure regulating valve 6. That is, this pressure regulating valve 4 has a pressure gradual increase characteristic in which the circuit pressure is gradually increased from a low pressure to a set pressure without abruptly rising to the set pressure unlike a relief valve, as is known. As a result, the direct coupling clutch 3 operates with a constant filling time.

[Problems to be solved by the device]

However, according to the above-mentioned conventional configuration, since the pressure rise by the pressure regulating valve 6 is linear, if the rise is made rapid, the filling time required to reach the clutch contact point is short, but the connection from here is performed. The time required for completion is shortened, and a smooth clutch engagement action cannot be obtained. On the contrary, if the pressure rise is set gently, there is a drawback that the filling time becomes long even though the smooth clutch engagement can be realized.

Therefore, the present invention can automatically change the rising characteristic of the pressure between the contact stroke until reaching the clutch contact point and the connecting stroke from here to the completion of the connecting, thereby shortening the filling time and smoothing. A direct coupling clutch control device for a torque converter capable of realizing both clutch coupling.

[Means for Solving the Problems]

The present invention relates to a main hydraulic circuit that connects a pump built in a torque converter and an oil chamber of a direct coupling clutch, and a sub hydraulic circuit that is connected in parallel with the main hydraulic circuit between the pump and the clutch oil chamber. The main hydraulic circuit is provided with an electromagnetic switching valve that switches to a communication position based on a clutch actuation signal, and the pressure of the main hydraulic circuit is gradually increased from a low pressure to a set pressure at the communication position of the electromagnetic switching valve. A pressure increasing means is provided, and in the sub-hydraulic circuit, a low-pressure operating valve that communicates the main hydraulic circuit with the clutch oil chamber only in a low-pressure region, and a flow of oil in a direction toward the clutch oil chamber. A check valve that allows only the above is provided.

[Action]

With this configuration, when the electromagnetic switching valve is switched to the communicating position and the circuit pressure is low, the combined oil of the main hydraulic circuit and the sub hydraulic circuit is supplied to the clutch oil chamber, so the clutch Quick contact stroke operation with a large amount of oil. Therefore, the filling time is short. When the clutch shifts to the engagement stroke and the circuit pressure increases, the low-pressure operating valve closes, the oil supply from the sub-hydraulic circuit to the clutch is stopped, and the clutch pressure gradually increases due to the pressure gradually increasing characteristic of the pressure gradually increasing means. As a result, a smooth clutch engagement action is performed.

〔Example〕

 An embodiment of the present invention will be described with reference to FIG.

11 is a torque converter, 12 is a pump, 13 is a direct coupling clutch, 14 is an oil chamber of this direct coupling clutch 13 and the pump 1
In the main hydraulic circuit that connects 2 to this main hydraulic circuit 14,
Similarly to the conventional case, an electromagnetic switching valve 15 that is operated by switching from a shut-off position a to a communication position b in the figure in response to an operation command signal from a computer is provided, and a pressure regulating valve 16 having a gradually increasing pressure characteristic is connected to the circuit 14. There is.

The main hydraulic circuit 14 is provided with a throttle valve 17 and a pressure increasing valve 18 between a connection point of the pressure regulating valve 16 with the primary side chamber and the electromagnetic switching valve 15.

The pressure increasing valve 18 has an oil chamber partitioned by a piston 19 into a pressure chamber 20 and a back pressure chamber 21, and the outlet pressure of the throttle valve 17 in the main hydraulic circuit 14 is introduced into the pressure chamber 20. On the other hand, in the back pressure chamber 21, the inlet 21a is connected to the outlet side of the pressure regulating valve 16 via the conduit 22, and the outlet 21b provided on the side surface is connected to the clutch oil chamber via the check valve 23 and the conduit 24, respectively. The pressure regulating valve 16, the pipe 22, the back pressure chamber 21 of the pressure increasing valve 18, the check valve 23, and the pipe 24 constitute an auxiliary hydraulic circuit 25 in parallel with the main hydraulic circuit 14.

The back pressure chamber 21 of the booster valve 18 is provided with a push spring 26 that exerts a spring force that opposes the pressure chamber 20, and the total force of this spring force and the hydraulic pressure of the back pressure chamber 21 overcomes the pressure chamber 20. When this happens, the piston 19 moves upward in the figure and the outlet 21b of the back pressure chamber 21 opens.

Next, the operation will be described.

When the electromagnetic switching valve 15 is in the shut-off position a, the main hydraulic circuit 14 is shut off by the electromagnetic switching valve 15, so pressure oil is not supplied to the oil chamber of the clutch 13 and the clutch 13 is in the off state. Becomes In this state, the main hydraulic circuit 14
Is adjusted to the set pressure of the pressure regulating valve 16, and this pressure is introduced into the pressure chamber 20 of the pressure increasing valve 18.
The piston 19 is lowered and the outlet 21b of the back pressure chamber 21 is closed.

From this state, when the electromagnetic switching valve 15 switches to the communication position b based on the operation signal, the pressure oil of the main hydraulic circuit 14 flows into the clutch oil chamber via the electromagnetic switching valve 15. Further, at this time, the pressure of the main hydraulic circuit 14 is lowered, so that the piston 19 is raised and the outlet 21b of the back pressure chamber 21 is opened. As a result, the sub-hydraulic circuit 25 communicates with the clutch oil chamber, the low-pressure oil of the circuit 25 merges with the oil of the main hydraulic circuit 14, and is supplied to the clutch oil chamber.

Thus, when the electromagnetic switching valve 15 is actuated, the low-pressure large-volume oil is supplied to the clutch oil chamber, so that the oil chamber is rapidly filled with the oil, and the clutch plate quickly strokes to the clutch contact point. Therefore, the filling time is short.

Next, when the clutch plate is further pressed from the clutch contact point and the clutch engagement (power transmission) is started, the pressure in the clutch oil chamber rises, and the pressure in the main hydraulic circuit 14 also rises accordingly. The piston 19 of the pressure increasing valve 18 descends again, and the outlet 21b of the back pressure chamber 21 closes. Therefore, the supply of oil from the sub hydraulic circuit 25 to the clutch oil chamber is stopped. Therefore, during the coupling stroke, pressure oil is supplied to the clutch oil chamber only from the main hydraulic circuit 14. The pressure oil of the main hydraulic circuit 14 is gradually increased from the low pressure at the clutch contact point by the throttling action of the throttle valve 17 and the pressurizing action of the pressurizing spring 26 in the back pressure chamber 21 of the pressure boosting valve 18. The clutch 13
Will be joined smoothly.

After that, when the electromagnetic switching valve 15 returns to the shut-off position a, the oil in the clutch oil chamber is returned to the tank 27 and the clutch 13 is turned off.

By the way, as the pressure gradually increasing means for gradually increasing the pressure of the main hydraulic circuit 14 in the engagement stroke of the clutch 13, a combination of the throttle valve 17 and the pressure increasing valve 18 is used in the above embodiment, but a pressure adjusting valve is used as in the conventional case. It is also possible. In this case, in order to smoothly engage the clutch in the contact stroke, a pressure regulating valve whose pressure rises slowly is used, and as the low pressure operating valve for securing the low pressure large oil amount in the contact stroke, the pressure increasing valve of the above embodiment is used. Instead of 18, it is possible to use, for example, a pilot switching valve or the like which is in a communicating position at low pressure and is in a shut-off position at high pressure.

[Effect of device]

As described above, according to the present invention, a main hydraulic circuit having an electromagnetic switching valve and a pressure increasing means, and a sub hydraulic circuit having a low pressure operating valve and a check valve are provided between the pump of the torque converter and the clutch oil chamber. And are provided in parallel, and in the contact stroke from the time the electromagnetic switching valve operates until the clutch starts the coupling operation, the combined oil of the main and sub hydraulic circuits is supplied to the clutch oil chamber for quick stroke operation. In the connecting stroke after this contact stroke, the auxiliary hydraulic circuit is shut off and the pressure in the main hydraulic circuit is gradually increased to perform the connecting operation gently, that is, the rising characteristics of the pressure are changed between the contact stroke and the connecting stroke. Because of the configuration, the filling time can be shortened and smooth clutch engagement can be achieved. It is capable of achieving capacity simultaneously.

[Brief description of drawings]

FIG. 1 is a hydraulic circuit configuration diagram showing an embodiment of the present invention, and FIG. 2 is a view corresponding to FIG. 1 showing a conventional example. DESCRIPTION OF SYMBOLS 11 ... Torque converter, 12 pumps, 13 ... Direct coupling clutch, 14 ... Main hydraulic circuit, 15 ... Electromagnetic switching valve, 17 ... Throttle valve which comprises a pressure increasing means, 18 ... A pressure increasing means, and acts as a low pressure operation valve. Pressure increasing valve, 19 ... piston of the pressure increasing valve, 20 ... same pressure chamber, 21 ... same back pressure chamber, 2
1a ... Inlet of back pressure chamber, 21b ... Same outlet, 26 ... Spring of back pressure chamber, 23 ... Check valve, 25 ... Sub hydraulic circuit.

Claims (1)

[Scope of utility model registration request] 1. A main hydraulic circuit connecting a pump built into a torque converter and an oil chamber of a direct coupling clutch, and an auxiliary hydraulic circuit connected in parallel with the main hydraulic circuit between the pump and the clutch oil chamber. The main hydraulic circuit includes an electromagnetic switching valve that switches to a communication position based on a clutch actuation signal, and the pressure of the main hydraulic circuit gradually increases from a low pressure to a set pressure at the communication position of the electromagnetic switching valve. A pressure gradually increasing means is provided, and in the sub-hydraulic circuit, a low-pressure actuating valve that communicates the main hydraulic circuit with the clutch oil chamber only in a low-pressure region, and oil in a direction toward the clutch oil chamber are provided. A direct coupling clutch control device for a torque converter, which is provided with a check valve that allows only the flow.