JPH064112Y2 - Disc brake piston seal structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a disc brake in which a piston is liquid-tightly and movably supported by a piston seal fitted in an annular groove formed around a cylinder hole of a caliper. Piston seal structure

[Prior Art] In a disc brake, for example, JP-A-55-4705 is used.
As disclosed in Japanese Patent Publication No. 1, a piston seal is fitted in an annular groove formed around a cylinder hole of a caliper, and an inner sliding contact surface of the piston seal is brought into pressure contact with the outer circumference of the piston.
A piston inserted in the cylinder hole is supported in a liquid-tight and movable manner to define a hydraulic chamber between the piston and the bottom of the cylinder hole, and a piston that moves to the disc rotor side when the brake is released is fixed. It is restored by rolling back (deformation restoring force) of the piston seal.

[Problems to be solved by the device]

This piston seal applies grease to the inner sliding contact surface when the piston is assembled so that the piston can move and return smoothly, but with the piston seal with the above structure, the entire inner sliding contact surface is Is in contact with the outer periphery of the piston, the heat generated during the braking action may cause grease breakage, and the piston seal may stick to the piston.

Therefore, it is conceivable to use an annular seal member having a circumferential groove formed in the sliding contact surface as a grease reservoir as disclosed in Japanese Utility Model Laid-Open No. Sho 62-92362 as a piston seal, but the piston seal is a seal. Since the other rollback amount of the function must be taken into consideration, the sliding contact surface is divided into multiple parts by the circumferential groove, so even if the circumferential groove that is simply a grease reservoir is formed, the rollback amount of the piston seal will be reduced. There was a fear that we could not get enough.

Therefore, an object of the present invention is to provide a piston seal structure for a disc brake in which the rollback amount of the piston seal can be easily obtained, grease breakage is eliminated, and sticking of the piston seal is prevented.

[Means for Solving the Problems]

In order to achieve the above object, the present invention has a piston seal fitted in an annular groove provided around a cylinder hole of a caliper, and a sliding contact surface inside the piston seal is movably fitted in the cylinder hole. In the piston seal structure of the disc brake that is pressed against the outer periphery, a plurality of the annular grooves are provided,
A feature is that a grease reservoir is formed between the piston seals fitted in the respective annular grooves.

[Action]

Therefore, since grease is stored in the gap between the piston and the cylinder hole between the adjacent piston seals, it is not necessary to form a circumferential groove that serves as a grease storage on the sliding contact surface of the piston seal in consideration of the rollback amount. The amount of rollback of the piston seal can be easily obtained.

〔Example〕

 An embodiment of the present invention will be described below with reference to the drawings.

The caliper 2 of the disc brake 1 connects the action portion 2a and the reaction portion 2b with a bridge portion 2c straddling the disc rotor 3, and inserts a piston 5 fitted in a cylinder hole 4 formed in the action portion 2a into a hydraulic chamber. 6 is moved in the direction of the disk rotor 3 by the pressure liquid supplied from the master cylinder (not shown), and the piston 5 pushes the friction pad 7 arranged on one side of the disk rotor 3 to move the disk rotor 3 to the disk rotor 3. The caliper 2 is moved by the reaction force acting on the piston 5 while slidingly contacting it, and the reaction portion 2b pushes the friction pad 8 arranged on the other side of the disk rotor 3 to bring it into sliding contact with the disk rotor 3. The friction pads 7 and 8 clamp the disk rotor 3 to perform a braking action.

On the inner circumference of the cylinder hole 4, a fitting groove 4a for the dust seal 9 is provided in the vicinity of the opening on the friction pad 7 side, and two annular grooves 4b, 4b are provided in the vicinity of the fitting groove 4a on the inner side. , Piston rings 10, 10 made of an elastomer material or the like are fitted in the annular grooves 4b, 4b, respectively.
The inner sliding contact surfaces of 0 and 10 are brought into pressure contact with the outer circumference of the piston 5, the piston 5 is fitted in the cylinder hole 4 in a liquid-tight and movable manner, and the grease reservoir 11 is formed between the piston seals 10 and 10. It prevents the piston seals 10 and 10 from sticking to the piston 5 by eliminating the breakage of grease due to the heat generated during the braking action.

[Effect of device]

As described above, according to the present invention, a plurality of annular grooves are provided around the cylinder hole of the caliper, the piston seals are fitted in the respective annular grooves, and the grease reservoir is formed between the adjacent piston seals. , It is possible to prevent the piston seal from sticking to the piston due to the loss of grease due to the heat generated during braking action, to stabilize the roll back of the piston seal at high temperature, and to consider the roll back amount. Since it is not necessary to form a circumferential groove serving as a grease reservoir on the sliding contact surface of the seal, the rollback amount of the piston seal can be easily obtained.

[Brief description of drawings]

1 shows an embodiment of the present invention, FIG. 1 is a front sectional view of a disc brake, and FIG. 2 is an enlarged sectional view showing a piston seal structure. 1 ... Disc brake, 2 ... Caliper, 4 ... Cylinder hole, 4b ... Annular groove, 10 ... Piston seal, 1
1-Grease pool

Claims (1)

[Scope of utility model registration request] 1. A piston seal is fitted in an annular groove provided around a cylinder hole of a caliper, and a sliding contact surface inside the piston seal is brought into pressure contact with an outer circumference of a piston movably fitted in the cylinder hole. A piston seal structure for a disc brake, wherein a plurality of the annular grooves are provided, and a grease reservoir is formed between the piston seals fitted in the respective annular grooves.