JPH03125070A - Control device for lock-up clutch - Google Patents

Abstract

PURPOSE:To effectively reduce shock when a lock-up clutch is engaged, by providing an orifice for reducing shock in clutch engagement in an working pressure oil passage at an apply room side. CONSTITUTION:The rotating number No of a turbine shaft is increased and a torque convertor 5 is entered into an approximately coupling area at a time t2, so that control pressure is caused by a solenoid valve 16 to switch a lock-up control valve 20 for communication of an inlet port 21b with an outlet port 21d and an outlet port 21c with a drain port 21e. So, a release room 8a for a lock-up clutch 8 promptly drains to guide working pressure through oil passages 12, 14 to an apply room 8b, the oil pressure of which is gradually increased because flow resistance is increased by an orifice or a choke 23 in this case. The lock-up clutch 8 is therefore engaged with a drive plate 3 smoothly for differential pressure between the apply room 8b and the release room 8a.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a control device for a lock-up clutch installed in a torque converter on the input side of an automatic transmission for a vehicle or a continuously variable transmission. This invention relates to measures to reduce shock when a lock-up clutch is engaged.

[Conventional technology]

In general, lock-up clutches are increasingly being used in torque converters in vehicle drive systems, and when the torque converter enters the coupling region during start-up or acceleration, the lock-up clutch is engaged to improve power transmission efficiency. It looks like this. As a control system for the lock-up clutch in this case, there is a method in which a lock-up control valve is operated by an electric signal to switch and supply operating pressure to the release side or apply side of the lock-up clutch.

Conventionally, regarding the control of the lock-up clutch, there is a prior art technique disclosed in, for example, Japanese Unexamined Patent Publication No. 63-297863. Here, operating pressure is guided to the lock-up control valve through one oil passage, and the oil passage is communicated from the lock-up control valve to the release chamber and apply chamber of the lock-up clutch. It is shown that when a control pressure is generated by a solenoid valve manually operated by an electric signal, an operating pressure is introduced by, for example, a lock-up control valve to release the clutch and operate the torque converter.

[Problem to be solved by the invention]

By the way, in the prior art described above, the lock-up control valve is configured so that the operating pressure is supplied to the release side and the apply side in exactly the same way, so the operating pressure is suddenly supplied to the apply side. When the lock-up clutch is engaged, an engagement shock occurs. Therefore, for example, control such as variable control of the duty ratio of the solenoid valve to gradually lower the control pressure and gradual switching of the lock-up control valve becomes necessary, and the software becomes complicated.

Furthermore, the electronic circuit for duty-controlling the solenoid valve is much more complex than the circuit for ON-OFF control, which increases cost.

The present invention has been made in view of the above points, and its purpose is to easily and accurately reduce clutch engagement shock by mechanical means, and further improve responsiveness when lock-up is released. An object of the present invention is to provide a control device for a lock-up clutch.

[Means to solve the problem]

In order to achieve the above object, the lock-up clutch control device of the present invention selectively introduces operating pressure into the lock-up control valve and into the release chamber and apply chamber of the lock-up clutch provided in the torque converter. In a hydraulic control system that operates a torque converter or locks up, the lockup control valve has two separately connected valves.
One of the operating pressure oil passages is configured to communicate with the apply chamber and the other with the release chamber, and an orifice for reducing clutch engagement shock is provided in the operating pressure oil passage on the apply chamber side. be.

[For production]

Based on the above configuration, the lock-up clutch is released by guiding the operating pressure to the release chamber of the lock-up clutch by the lock-up control valve, and the torque converter is activated. In addition, by guiding the operating pressure to the apply chamber, the lock-up clutch engages and locks up, but at this time, the flow resistance is large due to the orifice or choke in the operating pressure oil passage, so the oil pressure in the apply chamber gradually increases. This results in smooth engagement without any shock.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, reference numeral 1 denotes an engine, and a crankshaft 2 of this engine 1 is connected to a torque converter cover 4 and a pump impeller 5a of a torque converter 5 via a drive plate 3.

A turbine runner 5b of the torque converter 5 is connected to a turbine shaft B, and a stator 5C is guided by a one-way clutch 7. Further, a lock-up clutch 8 is disposed so as to be engageable between the turbine runner 5b and the drive plate 3 of the torque converter 5, and a release chamber 8a is provided on the drive plate 3 side of the lock-up clutch 8.
However, an apply chamber 8b is provided on the torque converter 5 side. The turbine shaft 6 is connected to an automatic transmission 9.

Regarding the hydraulic control system, reference numeral 10 indicates a torque converter 5. It is an operating pressure oil path for the lock-up clutch 8,
This operating pressure oil passage lO communicates with the lock-up control valve 20 via two oil passages 11 and 12, and the lock-up control valve 2
0 to the lock-up clutch 8 via oil passages 13 and 14.
The release chamber 8a and the apply chamber 8b are connected to each other. Moreover, the code|symbol 15 is a pilot pressure oil path,
One of the lock-up control valves 20 communicates with the solenoid valve 1B, and a control pressure oil passage 17 from the solenoid valve 16 communicates with the other lock-up control valve 20.

The lock-up control valve 20 has a spool 22 attached to the valve body 21.
with two inlet bows) 21a, 21b for the hydraulic oil line 11.12 and 2 for the oil line 13.14.
two exit boats 21e and 21d, and a drain boat 2
1C12H, and the entrance boat 2 is equipped with a spool 22.
1a and the exit boat 21C1, and the input robot 21b and the exit port 21d are communicated separately. Further, the pilot pressure of the pilot pressure oil passage 15 and the control pressure of the control pressure oil passage 17 act on the boats 21g and 21h at both ends of the spool 22, and when the control pressure is zero, the spool 22 is moved to the right side as shown in the figure. , and when control pressure is generated, the spool is moved to the left. The operating pressure oil passage 12 is provided with an orifice or choke 28 for reducing clutch engagement shock.

On the other hand, the oil passage 14 is provided with a relief valve 24 that limits the oil pressure during lock-up, and the oil passages 1g and 19 of the drain boats 21e and 21f' of the lock-up control valve 20 are provided with check valves 25 and 27 to prevent oil from leaking. provided.

An oil cooler 28 is provided at the outlet of the check valve 27 as required.

Further, the control unit 26 determines the region of the torque converter and the coupling based on the speed ratio of the engine rotation speed Nl and the turbine shaft rotation speed N, for example, and outputs an electric signal to the solenoid valve 16 for control when the coupling region is reached. Pressure is created.

Next, the operation of the lockup assembly control system constructed as described above will be described using the time chart shown in FIG.

First, when the vehicle is running, the power from the engine 1 is transferred to the drive plate 3. The signal is input to the pump side of the torque converter 5 , passes through either the torque converter 5 or the lock-up clutch 8 , and is transmitted to the automatic transmission 9 via the turbine shaft 6 . Therefore, when acceleration is requested from steady running by engaging the lock-up clutch 8 by depressing the accelerator at time t1 in FIG. becomes zero. Therefore, the lock-up control valve 20 is switched so that the inlet boat 21a, the outlet port 21C2, the outlet boat 21d, and the drain boat 21f are communicated by the spool 22 on which only the pilot pressure acts, and the operating pressure of the operating pressure oil passage IO is 11.13, it enters the release chamber 8a of the lock-up clutch 8, passes through the inside of the torque converter 5, and drains through the oil passage 14.19, thus releasing the lock-up clutch 8.
Torque converter 5 operates and torque is amplified. In this case, since the flow resistance of the oil passage is small, the lock-up clutch 8 is quickly released and the torque is doubled.

Next, after time t1 in FIG. 2, the turbine shaft rotational speed No increases, and at time t2, when the torque converter 5 almost enters the coupling region, a control pressure is generated by the solenoid valve IB, and the lock-up control valve 20 immediately closes the inlet boat. 21b and exit boat 21d, exit boat 21c and drain boat 2
It is switched to communicate Je. Therefore, the release chamber 8a of the lock-up clutch 8 is quickly drained, and the oil passage 1
Although the working pressure is introduced into the apply chamber 8b by 2.14,
In this case, since the flow path resistance is increased by the orifice or choke 23, the oil pressure in the apply chamber 8b gradually increases. Therefore, the lock-up clutch 8 smoothly engages with the drive plate 3 due to the differential pressure between the apply chamber 8b and the release chamber 8a, and is actually fully engaged at time t3, which is delayed from time t2.

At this time, oil is sealed in the torque converter 5 at the pressure set by the relief valve 24, and the torque converter 5 becomes inactive. In this way, after time t3, the lock-up clutch 8
This allows for more efficient power transmission.

It should be noted that the present invention is not limited to the above-mentioned embodiment, but can also be applied to a system in which the lock-up control valve is switched by an electromagnetic solenoid.

〔Effect of the invention〕

As described above, according to the present invention, engagement shock can be effectively reduced by smoothly engaging the lock-up clutch of the torque converter only when engaged.

Furthermore, the lock-up control valve has two operating pressure oil passages, one of which is equipped with an orifice or choke to change the flow passage resistance and mechanically reduce the engagement shock, so the control circuit can be controlled by software. It also becomes easier.

[Brief explanation of the drawing]

FIG. 1 is a block diagram showing an embodiment of the lock-up clutch control device of the present invention, and FIG. 2 is a time chart showing the release and engagement of the lock-up clutch. 5...torque converter, 8...lock-up clutch, 8a...-release chamber, 8b...apply chamber,
11. 12...Operating pressure oil passage, 13.14...Oil passage, 20...Lockup control valve, 23...Orifice or choke same

Claims (1)

[Scope of Claims] A hydraulic control system that operates or locks up a torque converter by selectively introducing operating pressure into a release chamber and an apply chamber of a lockup clutch provided in the torque converter using a lockup control valve, comprising: The lock-up control valve is configured such that one of two separately connected working pressure oil passages communicates with the apply chamber and the other with the release chamber, and the lock-up control valve is configured so that one of the two working pressure oil passages connected to each other communicates with the apply chamber and the other with the release chamber. A control device for a lock-up clutch, characterized in that it is provided with an orifice for reducing clutch engagement shock.