JPH027313Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a disc brake, and more particularly to a disc brake that enables early detection of damage to a piston seal provided between a cylinder and a piston.

[Prior Art] Figures 7 to 11 show a disc brake according to the prior art as described in Japanese Utility Model Application Publication No. 58-58127.

In the figure, 1 is a mounting member attached to the vehicle body (not shown), 2 is a brake housing, and the brake housing 2 is slidable on the mounting member 1 via two pins (not shown). is supported by 3 is a cylinder formed in the housing 2, and an annular groove 3A is formed on the inner peripheral surface of the cylinder 3.
and an annular groove 3C that is closer to the open end 3B than the annular groove 3A. 4 is a piston slidably inserted into the cylinder 3;
A hydraulic chamber 5 is defined between the cylinder 3 and the cylinder 3 . Reference numerals 6A and 6B are friction pads that are pressed against both sides of the disc 7 by the piston 4 and provide a braking action to the disc 7.

8 is provided between the cylinder 3 and the piston 4 by fitting the outer circumferential side into the annular groove 3A to prevent the oil in the hydraulic chamber 5 from leaking from between the cylinder 3 and the piston 4. With a piston seal that prevents
The piston seal 8 has an inner circumferential surface in liquid-tight contact with the outer circumferential surface of the piston 4, and also has a rollback function for returning the piston 4 to its original position.

Further, reference numeral 9 denotes an annular wiper seal provided between the cylinder 3 and the piston 4 closer to the open end 3B of the cylinder 3 than the piston seal 8, and the wiper seal 9 has an outer peripheral side facing the cylinder 3.
is installed in the annular groove 3C, and the inner circumferential side is the piston 4.
The piston 4 comes into sliding contact with the outer circumferential surface of the piston 4 to remove dust and the like adhering to the outer circumferential surface of the piston 4. Here, a groove 9A extending in the circumferential direction is provided at the center in the width direction on the inner peripheral side of the wiper seal 9, and thin sliding contact portions 9B, 9B are formed on both sides of the groove 9A. Further, one of the sliding contact portions 9B has a tenth
As shown in the figure and FIG. 11, notches 9C, 9C, . . . are provided which are spaced 90 degrees from each other in the circumferential direction.

In the conventional disc brake configured as described above, oil is supplied into the hydraulic chamber 5 to cause the piston 4 in the cylinder 3 to slide, and the piston 4 moves the friction pads 6A and 6B of the disc 7. Pressure is applied to both sides to provide a braking action to the disc 7, but if the piston 4 slides repeatedly over a long period of time, the piston seal 8, which holds the hydraulic pressure chamber 5 fluid-tight, will be damaged. may be done.

By the way, if the damage to the piston seal 8 is not detected early, the oil in the hydraulic chamber 5 will leak into the cylinder 3.
A large amount leaks from between the piston 4 and the piston 4, and it becomes impossible to apply a braking action to the disc 7,
This may cause vehicle collisions, etc.

For this reason, in the prior art, notches 9C, 9C, etc. are provided in one of the thin sliding contact parts 9B, 9B provided on the wiper seal 9, so that when the piston seal 8 is damaged, the cylinder 3 The oil leaking from between the piston 4 and the wiper seal 9 is facilitated to flow into the groove 9A of the wiper seal 9 through each notch 9C,
The oil flows into the groove 9A and contacts the other sliding contact portion 9B.
It is possible to detect damage to the piston seal 8 at an early stage.

However, such conventional techniques have unresolved problems as described below.

That is, the wiper seal 9 has two sliding contact parts 9B, 9.
Since the notch part 9C is provided in one sliding contact part 9B of B, it has assembly directionality, and when the wiper seal 9 is installed in the opposite direction, the groove part 9A
There is a problem in that the flow of oil into the piston seal 8 is delayed, and leakage of oil cannot be detected, making it impossible to detect damage to the piston seal 8 at an early stage.

[Problem that the invention attempts to solve]

The present invention was developed in view of the problems of the prior art described above, and the problems that the present invention attempts to solve are as follows:
To provide a disc brake in which a wiper seal is formed in a shape with no assembly direction, so that when a piston seal is damaged, oil can leak through the wiper seal, and the damage can be detected at an early stage.

[Means for solving problems]

In order to solve the above-mentioned problems, the feature of the configuration adopted by the present invention is that an annular groove into which an annular wiper seal is fitted is formed on the inner circumferential surface of the cylinder, and the inner circumference of the wiper seal is formed in the annular groove. The outer circumferential side of the wiper seal is fitted so that the circumferential side is in sliding contact with the piston, and a thin wall portion is formed on the outer circumferential side of the wiper seal with a space existing on both sides in the width direction.

[Effect]

With this configuration, when the outer circumferential side of the wiper seal is fitted into the annular groove of the cylinder, a thin wall portion is formed on the outer circumferential side of the wiper seal with spaces existing on both sides in the width direction, and the piston seal damage can be detected by the state of the oil flowing out through the thin walled portion, and the direction of assembly can be freely determined.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 6. In the embodiment, the same components as those of the prior art shown in FIGS. 7 to 11 described above are denoted by the same reference numerals, and the explanation thereof will be omitted.

1 to 3 show a first embodiment of the present invention.

In the figure, reference numeral 11 denotes an annular wiper seal used in this embodiment, and on the inner peripheral side of the wiper seal 11 there is a groove 1 extending in the circumferential direction at the center in the width direction.
1A is provided, and thin sliding contact portions 11B, 11B are provided on both sides of the groove portion 11A. Reference numeral 12 denotes a thin wall portion provided on the outer peripheral side of the wiper seal 11. The thin wall portion 12 is located approximately at the center in the width direction on the outer peripheral side of the wiper seal 11, and the thin wall portion 12 is cut out so that a space exists on both sides. By cutting it out as 13, the wall thickness in the width direction is made thinner, and it is designed so that when a pressure of about 2 to 4 kg/cm ² is applied, it bends and allows oil to flow out. .

Thus, when the outer peripheral side of the wiper seal 11 is installed in the annular groove 3B of the cylinder 3, the sliding contact parts 11B, 11B on the inner peripheral side slide against the outer peripheral surface of the piston 4, and dust attached to the outer peripheral surface of the piston 4 is removed. etc. are being removed.

Next, the operation of the disc brake configured as described above will be explained.

The disc brake operates in substantially the same manner as the conventional technology described above, but if the piston seal 8 is damaged, the oil in the hydraulic chamber 5 leaks from between the cylinder 3 and the piston 4 via the piston seal 8. It becomes like this. When the oil reaches the position of the wiper seal 11, the oil flows into one cutout 13 through the gap between the wiper seal 11 and the annular groove 3C of the cylinder 3, and presses the thin wall portion 12. Then, the thin wall portion 12 is bent toward the open end 3B of the cylinder 3 by applying a pressure of, for example, about 2 kg/cm ² , and the liquid flows out through the thin wall portion 12 to the open end 3B. Therefore, damage to the piston seal 8 can be detected early, and vehicle collisions and the like can be prevented. Furthermore, in the wiper seal 11, since the thin wall portion 12 is located approximately at the center in the width direction on the outer circumference side, the wiper seal 11 can be assembled in any direction, and the annular groove 3 of the wiper seal 11
Assembly to C is extremely easy.

4 to 6 show a second embodiment of the present invention, which has the following features added to the first embodiment.

That is, the feature of this embodiment is that radial grooves 21, 21 communicating with the thin wall portion 12 are provided on both sides of the wiper seal 11 in the width direction.

Here, each groove 21 extends in the radial direction from the inner circumferential side to the outer circumferential side of the wiper seal 11, and when the oil reaches the position of the wiper seal 11 when the piston seal 8 is damaged, the oil liquid on one side The cutout 1 is inserted from between the wiper seal 11 and the annular groove 3C via the groove 21.
It is formed so that it can easily flow into the inside of 3.

In the second embodiment configured in this manner, damage to the piston seal 8 can be detected at an early stage as in the first embodiment, but the oil that has reached the position of the wiper seal 11 is can immediately flow into the cutout 13 through the groove 21;
After bending the thin wall portion 12 toward the open end 3B, the oil fluid can immediately flow out to the open end 3B via the groove 21 on the other side, thereby further preventing damage to the piston seal 8. It becomes possible to detect

In addition, in each of the above embodiments, one thin wall portion 12 was provided on the outer peripheral side of the wiper seal 11, but the thin wall portion 1
2 is not limited to one, but a plurality of grooves 21 may be provided in the circumferential direction. In this case, a plurality of grooves 21 used in the second embodiment may be provided accordingly. good. Further, in each of the above embodiments, it has been described that the thin wall portion 12 is bent under a pressure of about 2 to 4 kg/cm ² .
When bent under pressure of Kg/ ^cm2 or less, from the outside,
This is because there is a risk that water, mud, etc. may flow in through the thin wall portion 12. If there is no such risk, the rigidity of the thin wall portion 12 may be made as small as possible.

[Effect of idea]

As described in detail above, according to the present invention, a thin wall portion with a thin wall thickness in the width direction is provided on the outer peripheral side of the wiper seal, so that when the piston seal is damaged, the oil in the cylinder flows outside through the thin wall portion of the wiper seal. In addition to being able to detect damage to the piston seal at an early stage, it is possible to eliminate the orientation of the wiper seal itself, thereby improving the ease of assembling the wiper seal.

[Brief explanation of the drawing]

1 to 3 show a wiper seal used in the first embodiment of the present invention, FIG. 1 is a front view thereof, FIG. 2 is a vertical sectional view thereof, FIG. 3 is a rear view thereof, and FIG. 4 is a wiper seal used in a first embodiment of the present invention. 6 to 6 show a wiper seal used in a second embodiment of the present invention, FIG. 4 is a front view thereof, FIG. 5 is a longitudinal cross-sectional view thereof, FIG. 6 is a rear view thereof, and FIGS. 7 to 11. The figures show a disc brake according to the prior art, Fig. 7 is a longitudinal cross-sectional view thereof, Fig. 8 is an enlarged view of the main part in Fig. 7, Fig. 9 is a front view of a wiper seal, and Fig. 10 is a longitudinal cross-section thereof. Figure, 11th
The figure is its rear view. 2... Brake housing, 3... Cylinder,
3B... Opening end, 4... Piston, 7... Disc, 8... Piston seal, 11... Wiper seal, 12... Thin wall portion, 21... Groove.

Claims (1)

[Claims for Utility Model Registration] (1) A cylinder formed in the brake housing, a piston slidably inserted into the cylinder, and a cylinder provided between the cylinder and the piston, A disc brake comprising an annular piston seal that prevents oil from leaking, and an annular wiper seal provided between the cylinder and the piston closer to the open end of the cylinder than the piston seal. , an annular groove into which the wiper seal is fitted is formed in the inner circumferential surface of the cylinder, and an outer circumferential side of the wiper seal is fitted into the annular groove so that the inner circumferential side of the wiper seal is in sliding contact with the piston; A disc brake characterized in that a thin wall portion is formed on the outer circumferential side of the wiper seal by forming a space on both sides in the width direction. (2) The disc brake according to claim (1), wherein the wiper seal is provided with radial grooves on both sides in the width direction that communicate with the space formed by the thin-walled portion. .