JPS642985Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] The present invention is a slave cylinder of a so-called non-adjustable clutch device that automatically changes the return position of an inserted piston depending on the degree of wear of the clutch disk. In particular, the present invention relates to a slave cylinder of a vehicle clutch device, which is equipped with a mechanism for releasing residual pressure within the cylinder when the cylinder is not in operation.

[Conventional technology]

An example of a slave cylinder of this type of clutch device having a mechanism that automatically adjusts the amount of play in the clutch in order to prevent clutch slippage caused by wear of the clutch disk will be explained with reference to FIGS. 4 and 5. .

A piston 2 is fitted into the slave cylinder 1 in a fluid-tight and movable manner to define a hydraulic chamber 3 between the tip of the piston 2 and the cylinder bottom 1a, and in the center of the cylinder bottom 1a, An introduction port 1b for introducing pressure fluid from a master cylinder (not shown) into the hydraulic pressure chamber 3 is provided, and the tip 2a of the piston 2 is formed into a truncated conical shape, and the tip 2a of the piston 2 is formed into a truncated conical shape. The proximal end of the valve device 4, which has a valve body 4a formed at the distal end, is inserted into the recess 2b formed in the distal end face of the cylinder by being biased toward the cylinder bottom 1a by a spring 4b contracted in the recess 2b. A cylindrical cap 5 is fluid-tightly inserted into the introduction port 1b, and one end of the cap 5 is slightly protruded into the hydraulic pressure chamber 3. A valve seat 5a is formed on which the valve body 4a is seated.

On the other hand, a spherical recess 2c is formed on the rear end side of the piston 2, and the spherical recess 2c includes:
One end extending from the cylinder open end 1c is fitted with the other end 6a of the push rod 6, which is engaged with a release fork (not shown).

Further, a spring 7 is disposed in the hydraulic chamber 3 and is compressed between the tip 2a of the piston 2 and the cylinder bottom 1a, and the spring 7 constantly urges the piston 2 toward the cylinder open end 1c. However, the end of the push rod 6 fitted into the recess 2c is always in contact with a release fork (not shown).

Also, the return position of the piston 2 when not in operation changes as the clutch disk (not shown) wears out.
In order to automatically adjust the play of the clutch, when the clutch disk gradually moves to the inner part of the cylinder and approaches its wear limit, the valve body 4a of the valve device 4 provided at the tip 2a of the piston 2 will close to the valve seat 5a of the base 5. It is set to move to a position where it is seated on and closes the introduction port 2b.

Therefore, in the conventional clutch device equipped with the slave cylinder configured as described above, when the clutch is operated with the clutch disc worn to near the wear limit, the inlet port 1b
The pressure in the hydraulic chamber 3 is increased by the pressure fluid introduced from the cylinder, and the piston 2 is pushed toward the cylinder open end 1c, and the piston 2 operates the release fork via the push rod 6 to move the clutch disk into the flywheel etc. (not shown) to cut off transmission of driving force.

Furthermore, when the clutch operation is released, the clutch disk tries to come into contact with the flywheel etc. again due to the action of the clutch spring (not shown), so this time the release fork pushes the piston 2 through the push rod 6. , and is pushed toward the cylinder bottom 1a against the elastic force of the spring 7.

Therefore, as the clutch disk wear progresses, the piston 2 that has been pushed toward the cylinder bottom 1a changes its return position toward the cylinder bottom 1a, and the valve element 4a is seated on the valve seat 5a and introduced. The mouth 1b will be closed.

Then, when the clutch is operated next time, the pressure fluid sent from the master cylinder first releases the valve body 4a that is blocking the inlet port 1b from the valve seat 5a, and opens the valve. is smaller in diameter than the inner diameter of the cylinder, the piston 2 is not pushed, and after the valve device 4 is inserted into the recess 2b against the elastic force of the spring 5 to open the valve, the inside of the hydraulic chamber 3 is opened. As a result, the pressure on the clutch pedal (not shown) increases at the initial stage of operation compared to the normal pedal force resistance, which causes the valve body 4 to open. After the valve, it rapidly decreases and returns to the same level as normal.

Based on this change in pedal force resistance, the driver can sense that the clutch disc is approaching its wear limit and that it is time to replace the clutch disc.

[Problem to be solved by the invention] Therefore, in the conventional slave cylinder, after the valve body 4a closes the inlet port 1b when the piston 2 returns, the clutch disk cannot be used without replacing it. In this case, the clutch disk gradually approaches the wear limit, and the valve device 4 compresses the spring 4b to move the return position of the piston 2 further toward the cylinder bottom 1a, so that the piston 2 completely returns to the return position. The valve body 4a closes the inlet port and prevents the discharge of pressure fluid to the master cylinder side, so the pressure inside the fluid pressure chamber 3 remains elevated and maintains a high pressure state, and the next time the clutch is operated. In such a case, the piston 2 will be pushed by just a small amount of pressure fluid sent from the master cylinder, and the rate of change in the pedal force resistance of the clutch pedal to be operated will be small, and due to changes in the pedal force resistance, the piston 2 will be pushed. There was a problem in that the effectiveness of notifying the clutch disc when it was nearing its wear limit was reduced.

This idea was created in view of the above problems.
The objective is to simplify the residual pressure release mechanism that is provided to repeatedly display changes in operating resistance such as clutch pedal depression force resistance that indicate that the clutch disc is nearing its wear limit until the worn clutch disc is replaced. It is said that

[Means for solving problems]

As a means to solve the above problems, in the present invention, hydraulic fluid from a master cylinder is introduced into a hydraulic pressure chamber defined in a cylinder by a piston fitted in a fluid-tight and movable manner. In a slave cylinder that intermittently operates a clutch via a release fork by pushing the piston, an inlet is provided at the end of the piston on the hydraulic pressure chamber side in the direction of an inlet for introducing the pressure fluid when the clutch disc has worn out by a predetermined amount. A valve body is provided that is elastically biased toward the valve body, and the valve body is integrally formed with a check valve portion in the center and a seal portion that can engage with the inlet at the peripheral edge of the check valve portion. It is characterized by what it did.

[Effect]

With this configuration, even if the valve body closes the inlet, the residual pressure in the hydraulic chamber can be released to the master cylinder side via the check valve provided at the tip of the piston.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 3.

FIG. 1 is a cross-sectional view showing the entire slave cylinder according to the present invention. A piston 12 is fitted in a cylinder 11 in a fluid-tight and movable manner to define a hydraulic chamber 13. An inlet 11b for introducing pressure fluid from a master cylinder (not shown) into the hydraulic pressure chamber 13 is provided at the center of the bottom 11a of the piston 12. The proximal end side of the valve device 14, which has a valve body 14a formed at the distal end thereof, is biased and inserted toward the bottom portion 11a side of the cylinder 11 by a spring 14b contracted in the recessed portion 12b, and the valve device 14 is inserted from the distal end of the piston 12. The protruding valve body 14a of the valve device 14
The introduction port 11 opens in the front bottom portion 11a.
b has a close contact surface 15a at the proximal end that comes into close contact with the end surface of a connection fitting (not shown) of a clutch hose that sends pressure fluid from the master cylinder, and an introduction path 15b and an inside of the hydraulic pressure chamber 13. A cylindrical cap 1 has a valve seat 15c formed at a slightly protruding tip.
5 is inserted in a liquid-tight manner.

On the other hand, a spherical recess 12c is formed on the rear end side of the piston 12.
, the other end 1 of the push rod 16 is formed into a spherical shape and one end 16a extending from the open end 11c of the cylinder 11 is engaged with the release fork 17.
6b is fitted.

Furthermore, a spring 18 is provided within the hydraulic pressure chamber 13.
is compressed between the piston 12 and the bottom 11a of the cylinder 11, and the piston 12 is connected to the spring 1.
8, the push rod 1 is always urged toward the cylinder open end 11c and fitted into the recess 12c.
The end portion 16a of the release fork 17 is kept in contact with the release fork 17 at all times.

The valve device 14, whose base end is inserted into the recess 12b of the piston 12, has a front surface of the valve body that is on the introduction port 11b side of the valve body 14a provided at the tip thereof, and a back surface of the valve body that is on the side of the piston 12. A communication hole 19 is formed so as to communicate with the two, and the valve body 14a is seated on a valve seat 15c formed at the tip of the cap 15 inserted into the introduction port 11b, thereby blocking the introduction path 15b. It is covered with a rubber lining 20 in order to improve the sealing performance during the process.

Furthermore, as shown in FIG. 2, the rubber lining 20 enclosing the valve body 14a has a U-shaped slit 22 in the portion of the sealing surface 21 that contacts the valve seat 15c that covers the opening of the communication hole 19. By providing the check valve 23, the check valve 23 is configured to be openable and closable, and the check valve 23 allows only the flow of the working fluid from the piston 12 side of the communication hole 19 to the introduction port 11b side.

The introduction path 15b of the base 15 inserted into the introduction port 11b is designed to automatically adjust the play of the clutch as the clutch disk (not shown) gradually wears out when the clutch disk (not shown) approaches its wear limit. The valve body 14a of the valve device 14 is provided at the tip 12a of the piston 12, which gradually moves its return position to the inner part of the cylinder, so that the clutch is closed when the clutch is not operated.

24 is a brewer plug, 25 is a mounting portion, 26 is an air vent hole for discharging air remaining in the recess 12b formed in the piston 12 when filling the hydraulic fluid, and 27 is a cup seal.

Next, the operation of this embodiment configured as described above will be explained.

In the clutch operation, the pressure fluid generated in the master cylinder by pressing the clutch pedal or the like is introduced into the hydraulic pressure chamber 13 from the introduction port 11b through the introduction passage 15b of the mouthpiece 15 via the clutch hose, and the hydraulic fluid is increased. The pressure inside the chamber 13 is increased to push the piston 12 toward the cylinder open end 11c.

The pushed piston 12 is moved by the push rod 1
6 to operate the release fork 17,
The clutch disk is separated from the flywheel or the like (not shown) to cut off transmission of driving force.

Furthermore, when the clutch operation is released, the clutch disk comes into contact with the flywheel etc. again due to the action of the clutch spring (not shown) and tries to transmit the driving force, so this time the release fork 1
7 connects the piston 12 via the push rod 16
is pushed toward the cylinder bottom 11a against the elastic force of the spring 18.

Then, the clutch disk wears out to near the wear limit, and the return position of the piston 12 is changed to the valve body 14a.
When the valve is seated on the valve seat 15c formed at the tip of the base 15 and the clutch is operated in a state where the introduction passage 15b is closed, the pressure fluid sent from the master cylinder first closes the introduction passage 15b. The valve is opened by separating the body 14a from the valve seat 15c, but since the diameter of the introduction passage 15b is smaller than the inner diameter of the cylinder, the piston 12 is not pushed, and the valve device 14 is moved by the elastic force of the spring 14b. After fitting into the recess 12b and opening the valve against the
The pressure fluid introduced into the hydraulic pressure chamber 13 causes the hydraulic pressure chamber 13 to
The pressure inside the piston 12 is increased to push the piston 12.

For this reason, the pedal effort resistance of the clutch pedal that performs clutch operation increases at the initial stage of operation compared to the pedal effort resistance under normal conditions, and after the valve opens, it rapidly decreases and returns to the same level as under normal conditions. The changing characteristic of the pedal force resistance allows the driver to sense that the clutch disc is approaching its wear limit and that it is time to replace the clutch disc.

In this way, when the piston 12 returns, the valve body 14
If the clutch disk is continued to be used without replacing it after the clutch disk a has been seated on the valve seat 15c and has begun to block the introduction path 15b, the clutch disk will wear further and gradually approach the wear limit, causing the valve to become damaged. device 14
compresses the spring 14b and the piston 12
Since the return position of the piston 12 is gradually moved toward the cylinder bottom 11a, the valve body 14a seats on the valve seat 15c and closes the introduction passage 15b before the piston 12 completely returns to the return position.

Therefore, as shown in FIG.
Since the inside of the hydraulic pressure chamber 13 remains in a high pressure state even after the introduction passage 15b is closed, the pressure liquid inside the hydraulic pressure chamber 13 is absorbed by the rubber lining 20 that encloses the valve body 14a of the valve device 14. The introduction port 11 of the communication hole 19
The check valve 23 formed in the portion covering the b side is pressed to open the valve, allowing the pressure fluid in the hydraulic pressure chamber 13 to escape to the master cylinder side and releasing the residual pressure in the hydraulic pressure chamber 13.

[Effect of idea]

As explained above, the clutch slave cylinder according to the present invention has a check valve section at the center of the end of the piston fitted into the cylinder on the hydraulic pressure chamber side.
A seal portion is integrally formed on the peripheral edge of the check valve portion, and when the clutch disk wears out by a predetermined amount, the pressure fluid inlet is closed by the valve body, so that the clutch disk approaches its wear limit and the piston Even if the valve body blocks the inlet before returning to the return position,
Since the pressure fluid in the hydraulic pressure chamber is released from the check valve to the master cylinder side, a reliable release of residual pressure can be achieved with a simple structure. Change characteristics of operating resistance, such as pedal force resistance, can be made to appear repeatedly every time the clutch is operated until a worn clutch disc is replaced.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the present invention, in which FIG. 1 is a cross-sectional front view showing the entire slave cylinder, and FIG. 2 is a cross-sectional perspective view of a rubber lining forming a check valve. , Fig. 3 is an enlarged view of the main parts showing the operating state of residual pressure release, Figs. 4 and 5 show the conventional slave cylinder, and Fig. 4 is a cross-sectional front view showing the return position of the piston in normal state. Figure, 5th
The figure is a sectional front view showing the return position of the piston when the clutch disk approaches its wear limit. 11...Cylinder, 11b...Inlet, 12...
... Piston, 13 ... Hydraulic pressure chamber, 14 ... Valve device,
14a... Valve body, 15... Base, 15b... Inlet path, 15c... Valve seat, 16... Push rod,
17... Release fork, 19... Distribution hole, 2
0...Rubber lining, 21...Sealing surface, 22
...Slit, 23...Check valve.

Claims (1)

[Scope of utility model registration request] Hydraulic fluid from a master cylinder is introduced into a hydraulic pressure chamber defined in a cylinder by a piston fitted in a fluid-tight and movable manner, and the piston is pushed to intermittently operate the clutch via a release fork. In the slave cylinder, a valve body is provided at the end of the piston on the hydraulic pressure chamber side, and is elastically biased toward the inlet for introducing the pressure fluid when the clutch disk wears out by a predetermined amount. A slave cylinder for a clutch, characterized in that a check valve part is integrally formed in the center, and a seal part that can be engaged with the introduction port is formed at the peripheral part of the check valve part.