JPH021576Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] The present invention relates to improving the sealing performance of a release cylinder, particularly a cup, and can be used to operate a clutch device mounted on a vehicle such as an automobile. Concerning what works.

[Conventional technology]

Conventionally, in a release cylinder that operates a clutch device installed in an automobile by receiving hydraulic pressure from a master cylinder, a cup mounted on the piston slides against the inner peripheral surface of the cylinder, thereby sealing the inside and outside of the cylinder. configured to ensure that

[Problem that the invention attempts to solve]

However, in such a release cylinder, when the piston slides on the cylinder, scratches are generated on the inner peripheral surface of the cylinder, and the cup may be damaged when it slides on the damaged area. Therefore, there is a concern that the sealing performance of the cup may be degraded.

Therefore, surface hardening treatment is performed to prevent damage between the piston and cylinder.
Not only is productivity reduced, but the damage prevention effect may not always be sufficient.

[Purpose of invention]

An object of the present invention is to provide a release cylinder that can prevent damage to the cup and maintain the desired sealing performance.

[Summary of the idea]

The present invention is configured so that the cup does not slide in the piston sliding area in the cylinder by forming a non-sliding part on the outer periphery of the piston adjacent to the cup and having a length longer than the stroke of the piston. Even if an abrasion occurs on the inner circumferential surface of the cylinder due to movement, the cup is prevented from being damaged by the damage.

〔Example〕

FIG. 1 is a longitudinal sectional view showing a release cylinder as an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing its operating state.

In this embodiment, the release cylinder 1 includes a cylinder 2, which is screwed onto one end of a release fork (not shown) in a clutch device at a flange portion 3 protruding from its outer periphery. It's becoming like that. cylinder 2
One end of the cylinder chamber 4 is closed,
A passage 5 is opened in this closing wall so as to communicate with the cylinder chamber 4. This passage 4 communicates with a master cylinder (not shown) operated by a clutch pedal, so that hydraulic pressure can be supplied to and discharged from the cylinder chamber 4.

The other end of the cylinder chamber 4 is open, and one end of the push rod 6 is inserted into this opening with a retractable dust cover 7 attached between it and the cylinder 2. The position of the push rod 6 is regulated by being supported by a main body (not shown) of the clutch device at its protruding end.

A piston 8 is fitted in the cylinder chamber 4 so as to be slidable in the direction of the cylinder center, and a push rod 6 is abutted against the end surface of the piston 8 on the cylinder opening side via a spherical joint 9.

A cup 10 is fixedly wound around the outer periphery of the piston 8, and the cup 10 is formed so as to be in sliding contact with the inner circumferential surface of the cylinder chamber 4 on the outer periphery, and is slidable on one side of the piston 8. is configured to support. An example of a configuration for supporting one side of the piston 8 is a configuration in which a relatively hard elastic material is used and the piston 8 is rigidly molded into the structure shown in FIG.

A non-sliding contact portion 11 that does not make sliding contact with the inner circumferential surface of the cylinder chamber 4 is cut in the intermediate portion of the outer periphery of the piston 8 in the shape of an annular band so as to be adjacent to the cup 10 on the push rod 6 side. Contact part 11
The length A in the axial direction is set to be longer than the longest stroke S of the piston 8. In addition, the outer diameter B of the sliding contact portion 12 of the piston 8 that comes into sliding contact with the inner circumferential surface of the cylinder chamber 4, and the outer diameter C of the non-sliding contact portion 11.
and the outer diameter D of the portion adjacent to the non-sliding contact portion 11 of the cup 10 are set so as to satisfy the following equations.

C>D...(1) B>C+0.5(mm)...(2) Next, the action will be explained.

In the normal state where the clutch pedal is not depressed, it is pushed relative to the push rod 6 by the biasing force of a return spring (not shown) stretched between the main body of the clutch device and the release fork. As shown in FIG. 1, the piston 8 is located in the cylinder chamber 4 at a position closest to the passage 5 (hereinafter referred to as the shortened limit).
being pushed back.

At this time, in the clutch device, the drive side and the driven side are connected by the clutch disk being pressed against the flywheel via the pressure plate by the biasing force of the spring.

When the clutch pedal is depressed and hydraulic pressure is supplied from the master cylinder to the cylinder chamber 4 in the release cylinder 1 through the passage 5, the piston 8
slides inside the cylinder chamber 4 in a direction away from the passage 5. When hydraulic pressure is powerfully supplied, the piston 8 is pushed to the position within the cylinder chamber 4 that is furthest away from the passage 5 (hereinafter referred to as the extension limit), as shown in FIG. Become.

When the piston 8 is pushed by hydraulic pressure, the cylinder 2 moves in a direction away from the main body because the piston 8 abuts against the push rod 6 whose position is regulated by the main body of the clutch device. Due to this relative movement of the cylinder 2, the release fork fixed to the cylinder 2 is rotated against the return spring.

In the clutch device, the rotation of the release fork causes the pressure plate to be pulled back against the biasing force of the spring, so that the pressed state between the flywheel and the clutch disk is relaxed or released. The connection between the driving side and the driven side will be released.

When the clutch pedal is no longer depressed and the hydraulic pressure is discharged from the cylinder chamber 4 in the release cylinder by the master cylinder, the cylinder 2 is fixed to the release fork and the return spring always moves the clutch device toward the main body. Since the piston 8 is biased and its position is restricted by the push rod 6, the piston 8 is relatively pushed in the cylinder chamber 4 in the direction of the passage 5 by the biasing force of the return spring, and finally, as shown in FIG. will be pushed back to the shortened limit, as shown in .

When the piston 8 is pushed back, the release fork fixed to the cylinder 2 relatively rotates in the original direction, so in the clutch device, the clutch disk attaches the spring to the flywheel via the pressure plate. They are pressed against each other by force, thereby connecting the driving side and the driven side.

In this way, the piston 8 and the cylinder 2 move relative to each other to expand and contract, thereby performing engagement and disengagement in the clutch device. During this operation, a seal between the inside and outside of the cylinder chamber 4 is maintained by the cup 10 sliding on the inner peripheral surface of the cylinder chamber 4.

In the above-described operation, when the piston 8 moves through the longest stroke S from the contraction limit to the extension limit, the sliding portion 1 of the piston 8 against the inner circumferential surface of the cylinder chamber 4
The sliding area E of the cup 10 is formed on the opening side of the cylinder chamber 4, and the sliding area F of the cup 10 is formed on the opening side of the cylinder chamber 4.
It is formed on the passage 5 side portion of the. And sliding contact part 1
A non-interference area G is formed at the boundary between the sliding area E of the cup 10 and the sliding area F of the cup 10.

The reason why the sliding area E of the sliding contact part 12 and the sliding area F of the cup 10 are separated is that the non-sliding contact part 11 is located between the sliding contact part 12 and the cup 10 on the outer periphery of the piston 8. This is because the length A is longer than the longest stroke S of the piston 8.
That is, since the cup 10 is separated from the sliding contact part 12 by the longest distance S by the non-sliding contact part 11, the cup 10 does not reach the sliding area E of the sliding contact part 12.

In this way, the cup 10 does not slide on the sliding area E of the sliding contact part 12, so even if there is an abrasion on the inner peripheral surface of the cylinder chamber 4 in the sliding area E, the cup 10 10 is not damaged by this damage.

When sliding in the cylinder chamber 4, the piston 8 is supported at both ends by the sliding contact portion 12 and the cup 10, so that the piston 8 is properly guided in sliding.

According to this embodiment, the cup is not damaged due to damage that may occur in the cylinder chamber, so it is possible to prevent the seal from deteriorating due to damage to the cup. This prevents pressure oil from leaking from the cylinder chamber.

Even if damage occurs to the sliding area of the piston sliding contact portion of the cylinder chamber, deterioration in the sealing performance of the cup can be avoided, so that the surface hardening treatment of the cylinder chamber can be relaxed or omitted.

Since the piston is supported at both ends by the sliding contact portion and the cup, sliding movement is properly guided, so that the piston and the cylinder can extend and contract smoothly.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and may be modified without departing from the gist thereof.
It goes without saying that various changes are possible.

For example, the cup is not limited to having a structure that supports one side of the piston, but the sealing performance of the cup may be improved by making the cup flexible. In such a case, it is preferable to design the piston so that the sliding contact portion is sufficiently long.

In addition to attaching the release fork to the cylinder side, the release fork may be attached to the piston side.

The return spring may be configured to fit into the cylinder chamber.

〔effect〕

As explained above, according to the present invention, it is possible to avoid the cup from sliding in the sliding area of the sliding contact portion of the piston in the cylinder, so that the sliding of the piston can prevent the occurrence of damage in the cylinder chamber. It is possible to prevent the cup from being damaged due to certain damage.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing a release cylinder as an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view showing its operating state. 1...Release cylinder, 2...Cylinder, 3
...flange section, 4 ... cylinder chamber, 5 ... passage, 6 ... push rod, 7 ... dust cover, 8 ... piston, 9 ... spherical joint section, 10 ...
...Cup, 11...Non-sliding contact part, 12...Sliding contact part,
A... Length of non-sliding contact part, E... Sliding area of sliding contact part, F... Sliding area of cup, S... Longest stroke.

Claims (1)

[Claims for Utility Model Registration] (1) In a release cylinder that operates a clutch device by relatively expanding and contracting a piston and a cylinder in response to hydraulic pressure from a master cylinder, a cup at one end of the piston is connected to the cylinder. 1. A release cylinder, characterized in that the release cylinder is externally covered in sliding contact with the cup, and a non-sliding contact portion is formed on the outer periphery of the piston adjacent to the cup and having a length longer than the stroke of the piston. (2) The release cylinder according to claim 1, wherein the cup is configured to support one side of the piston.