JPH0842601A - Clutch release cylinder - Google Patents

Abstract

PURPOSE:To simplify the structure of a clutch release cylinder, which senses wear limit of a clutch disc on the basis of a change of the operating force. CONSTITUTION:A clutch release cylinder has a restriction hole 19a, which is formed in a hydraulic passage 19 adjacent to a liquid pressure chamber 15, and the peripheral surface 12a, which is formed in a piston 12 and which is formed with a fine clearance between the inner peripheral surface of a cylinder main body 11 and itself. When wear of a clutch disc achieves the wear limit, the restriction hole 19a and the peripheral surface 12 overlap with each other so as to form an orifice.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a clutch release cylinder for detecting wear of a clutch disc.

[0002]

2. Description of the Related Art As a conventional technique of this kind, there is
The one disclosed in Japanese Patent Publication No. 2986-29 is known. This is a cylinder main body, a piston slidably inserted in the cylinder main body, one end abutting the piston and the other end extending to the open end of the cylinder main body and releasing the driving force to the clutch disc. A rod portion that abuts the fork, a hydraulic chamber between the closed end of the cylinder body and one end of the piston that faces the closed end, and a hydraulic passage formed in the cylinder body for supplying and discharging hydraulic pressure to the hydraulic chamber, And a biasing member that is disposed in the hydraulic chamber and biases the piston toward the open end of the cylinder body.The means for detecting the wear limit of the clutch disc is provided between the closed end of the cylinder and the piston. The valve member is arranged and held by a holding portion formed on the piston. The valve member is formed with a through hole whose one end fits into the supply hole, and the urging member is in contact with the end portion. The biasing member is disposed in a recess formed in the end of the piston and biases the valve member toward the closed end of the cylinder. This is because when the clutch disc is released from the clutch operation at the wear limit, the return position of the piston moves to the closed end side in the cylinder and the valve member comes into contact with the closed end. When the clutch is operated, the supply hole for supplying the hydraulic pressure is closed by the valve member, so that the piston is not pushed and the valve member is placed in the recess of the piston against the urging force of the urging member. After fitting and opening the valve member, the pressure in the hydraulic chamber is increased by the hydraulic pressure supplied to the hydraulic chamber and the piston is pushed.

Therefore, the pedaling force resistance of the clutch pedal for operating the clutch is increased in the initial stage of operation as compared with the pedaling force resistance in the normal state, and is rapidly decreased after opening the valve to return to the same level as in the normal state. The driver can sense the wear limit of the clutch based on the change in the pedaling force.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
A valve member is used as a means for detecting the wear limit of the clutch disc, but since the valve member is held by a holding portion formed on the piston, the structure becomes complicated. Further, since a biasing member for biasing the valve member is required, the number of parts is increased and the cost is increased.

SUMMARY OF THE INVENTION It is an object of the present invention to simplify the structure of a clutch release cylinder which detects the wear limit of a clutch disc by a change in pedaling force.

[0006]

[Means for Solving the Problems] Means taken in the present invention for solving the above-mentioned problems are as follows:
A piston slidably fitted in the cylinder body, and a rod portion having one end abutting the piston and the other end abutting a release fork extending to the open end of the cylinder body and blocking the driving force to the clutch disc. A hydraulic chamber between the closed end of the cylinder body and one end of the piston facing the closed body, an urging member disposed in the hydraulic chamber for urging the piston toward the open end of the cylinder body, In a clutch release cylinder having a hydraulic passage for supplying and discharging hydraulic pressure to the chamber, a small amount is formed between the throttle hole formed in the hydraulic passage in contact with the hydraulic chamber and the inner peripheral surface of the cylinder body formed in the piston. The outer peripheral surface forming a clearance, and the throttle hole and the outer peripheral surface are overlapped with each other at the wear limit of the clutch disc to form an orifice.

[0007]

With the clutch release cylinder described above,
When the hydraulic pressure is supplied to the hydraulic chamber by the clutch operation, the piston moves to the open end side and pushes the release fork via the rod portion. As a result, the clutch disc is separated from the flywheel or the like to interrupt the transmission of the driving force. After the clutch is operated, the hydraulic pressure in the hydraulic chamber is discharged, the release fork moves the piston to the closed end side of the cylinder body against the biasing force of the spring, and the driving force is transmitted to the clutch disc again. Also, due to the wear of the clutch disc, the return position of the piston moves to the closed end side of the cylinder body. When it further wears and approaches the wear limit of the clutch disc, the throttle hole of the cylinder body and the outer peripheral surface of the piston overlap each other. Since the diameter through which the hydraulic pressure is discharged is made small by the throttle hole, an orifice is instantly formed when the outer peripheral surfaces of the pistons overlap each other. When the clutch operation is performed in this state, the supply of hydraulic pressure is limited by the orifice, so that the pedaling force resistance during the clutch operation increases. If the user continues to step in this state, the hydraulic pressure is gradually supplied to the hydraulic chamber, and the superposition between the throttle hole and the minute clearance is released. Then, the throttle hole can supply the hydraulic pressure to the hydraulic chamber as usual, and the pedaling force resistance is rapidly reduced to the same level as in the normal state. The characteristic of this change in pedaling force allows the driver to sense that the clutch disc is at the wear limit. For this reason, since a separate member as a means for changing the pedaling force is not required, wear of the clutch disc can be detected with a simple structure, and the cost can be reduced.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings.

FIG. 1 shows a sectional view of a clutch release cylinder 10. As shown in the figure, the clutch release cylinder 10 includes a cylinder body 11 and a cylinder body 11
A piston 12 slidably fitted in the release fork 13 and a release fork 13 having one end abutting the piston 12 and the other end extending to the open end of the cylinder body 11 and blocking the driving force to a clutch disc (not shown). The rod portion 14 in contact with the closed end of the cylinder body 11 and the piston 12 facing the closed end.
Between the one end of the cylinder body 11, a spring 16 arranged in the hydraulic chamber 15 for urging the piston 12 toward the open end of the cylinder body 11, and a boot arranged at the open end of the cylinder body 11. It is composed of 17 and.

A bleeder plug 18 for bleeding air from the hydraulic chamber 15 is arranged on the closed end side of the cylinder body 11. Further, a hydraulic passage 19 for supplying and discharging hydraulic pressure to the hydraulic chamber 15 is formed. Then, by operating a clutch pedal (not shown), hydraulic pressure is supplied to the hydraulic chamber 15, and after releasing the clutch pedal, the hydraulic pressure in the hydraulic chamber 15 is discharged from the hydraulic passage 19. An attachment portion 20 that can be attached to the vehicle body is integrally formed with the cylinder body 11.

A seal cup 21 is fitted into the piston 12 to seal the hydraulic pressure from the hydraulic chamber 15 so as not to leak to the open end of the cylinder body 11. Further, although the opening directions of the two seal cups 21 are the same, the present invention is not limited to this, and it is conceivable that the two seal cups 21 are symmetrically inserted. The piston 12 is in contact with one end of the rod portion 14 by the urging force of the spring 16, and the other end of the rod portion 14 is in contact with the release fork 13. The outer peripheral surface 12a of the piston 12 is slightly smaller than the inner peripheral surface of the cylinder body 11 so that a minute clearance is formed between the outer peripheral surface 12a of the piston 12 on the closed end side and the inner peripheral surface of the cylinder body 11. Has been formed. or,
The opening of the hydraulic passage 19 that opens to the hydraulic chamber 15 is a throttle hole 1.
9a, and this throttle hole 19a is formed on the outer peripheral surface 1 of the piston 12 when the wear of a clutch disc (not shown) reaches its limit.
It is positioned so as to overlap with 2a, and the diameter through which the hydraulic pressure is discharged is made small by the throttle hole 19a. Therefore, when the outer peripheral surface 12a of the piston 12 overlaps, an orifice is instantly formed. If you operate the clutch in this state,
Since the supply of hydraulic pressure to the hydraulic chamber 15 is restricted by the orifice, the pedaling force resistance at the time of operating the clutch increases. When the hydraulic pressure is supplied to the hydraulic chamber 15 and the piston 12 is pushed to release the superposition of the outer peripheral surface 12a and the throttle hole 19a, the pedal force returns to the normal state.

Next, the operation of this embodiment will be described.

In the clutch device, the hydraulic pressure generated in a master cylinder (not shown) by depressing the clutch pedal causes a hydraulic pressure passage 19 through a clutch tube (not shown).
Is supplied to the hydraulic pressure chamber 15 to increase the pressure in the hydraulic pressure chamber 15 and push the piston 12 toward the open end of the cylinder body 11.

The pushed piston 12 has a rod portion 14
The release fork 13 is actuated via the lever to separate the clutch disc from the flywheel (not shown) to interrupt the transmission of the driving force.

When the clutch operation is released, the hydraulic chamber 1
The hydraulic pressure of No. 5 is discharged from the hydraulic passage 19, and the clutch disc comes into contact with the flywheel again by the action of a clutch spring (not shown) to transmit the driving force, so that the release fork 13 causes the piston 1 via the rod portion 14.
2 against the urging force of the spring 16 and the cylinder body 11
Pushes toward the closed end of.

Then, the clutch disc wears to near the wear limit, and the return position of the piston 12 moves to the closed end side of the cylinder body 11 as the release fork 13 moves to the return position. Then, when the wear of the clutch disc progresses and reaches the wear limit, the outer peripheral surface 12a of the piston 12 forming the minute clearance and the throttle hole 19a overlap with each other (this is shown in FIG. 2). When the clutch operation is performed at this time, the pedaling force resistance for performing the clutching operation is increased in the initial stage of the operation as compared with the pedaling force resistance in the normal state by the orifice formed between the outer peripheral surface 12a and the throttle hole 19a. Then, when the piston 12 is gradually pushed and the superposition of the outer peripheral surface 12a of the piston 12 and the throttle hole 19a is released, the pedaling force resistance is rapidly reduced to the same level as that in the normal state. The change characteristic of the pedaling force resistance makes it possible to detect that the clutch disc is about to be replaced.

From the above, it is possible to detect the wear of the clutch disc and obtain the characteristic of the change in pedaling force with a simple structure without the need for a separate component.

[0018]

According to the above-mentioned clutch release cylinder, the opening of the hydraulic passage which opens to the hydraulic chamber is used as a throttle hole, and a minute clearance is provided between the inner peripheral surface of the cylinder body and the outer peripheral surface on the piston closed end side. The outer peripheral surface of the piston on the closed end side is formed to be slightly smaller than the inner peripheral surface of the cylinder body so that the orifice is formed by superposition of the throttle hole and the outer peripheral surface of the piston at the wear limit of the clutch disc. . With this orifice, the pedaling force resistance at the time of operating the clutch increases, and the superposition of the throttle hole and the outer peripheral surface of the piston is released to provide the pedaling force resistance in the normal state. Since the change in the pedal effort can be obtained without the need for a separate member, the wear of the clutch disc can be detected with a simple structure, and the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a sectional view of a clutch release cylinder according to an embodiment of the present invention.

FIG. 2 shows a sectional view of a clutch release cylinder according to an embodiment of the present invention.

[Explanation of symbols]

 11 ... Cylinder body 12 ... Piston 12a ... Outer peripheral surface 13 ... Release fork 14 ... Rod part 15 ... Hydraulic chamber 19 ... Hydraulic passage 19a ... Throttle hole

Claims (1)

[Claims] 1. A cylinder body, a piston slidably inserted in the cylinder body, one end abutting the piston and the other end extending to an open end of the cylinder body and driving to a clutch disc. A rod portion that abuts a release fork that shuts off force, a hydraulic chamber between the closed end of the cylinder body and one end of the piston that faces the closed end, and the piston that is disposed in the hydraulic chamber In a clutch release cylinder having a biasing member for biasing the cylinder body toward the open end and a hydraulic passage for supplying and discharging hydraulic pressure to and from the hydraulic chamber, the clutch release cylinder is formed in the hydraulic passage in contact with the hydraulic chamber. A throttle hole and an outer peripheral surface which is formed on the closed end side of the piston and forms a minute clearance with the inner peripheral surface of the cylinder body. A clutch release cylinder characterized in that a bore and an outer peripheral surface of the piston are overlapped with each other to form an orifice.