Disc brake and piston boot

Patent metadata

Field	Value
Publication number	US-2022056972-A1
Application number	US-201917416896-A
Country	US
Kind code	A1
Filing date	Dec 2, 2019
Priority date	Dec 19, 2018
Publication date	Feb 24, 2022
Grant date	—

Abstract

A disc brake including: a piston; a cylinder including a bore portion, which movably accommodates the piston, and a step portion formed on an opening end side of the bore portion; and a piston boot arranged between a tip side of the piston and a small diameter step portion of the cylinder. The piston boot includes: a large diameter annular fitting portion containing an annular metal member so as to be fitted to the small diameter step portion; a bellows portion, which extends from the large diameter fitting portion, is increased in its diameter from the large diameter fitting portion to an outer peripheral side, and is also deformed and extended from the large diameter fitting portion toward an inner peripheral side; and a small diameter fitting portion formed at an end portion of the bellows portion so as to fit to an outer periphery of the piston.

First claim

1 . A disc brake, comprising:
a piston configured to press at least one of a pair of pads opposed to each other on both surfaces of a disc; a cylinder which includes: a bottomed bore portion for accommodating the piston movably in an axial direction; and a step portion formed on an opening end side of the bottomed bore portion from which a tip of the piston protrudes, the step portion having an annular shape and a diametrical dimension larger than an inner diameter of the bottomed bore portion; and a piston boot which is arranged between the tip side of the piston and the step portion of the cylinder, and includes a bellows portion configured to expand and contract along with the movements of the piston, wherein the piston boot includes: a large diameter fitting portion having an annular shape and containing an annular metal member so as to be fitted to the step portion; the bellows portion, which extends from the large diameter fitting portion, is increased in its diameter from the large diameter fitting portion to an outer peripheral side, and is also deformed and extended from the large diameter fitting portion toward an inner peripheral side; and a small diameter fitting portion which is formed, at an end portion of the bellows portion, into an annular shape having a shorter diameter than that of the large diameter fitting portion so as to be fitted to an outer periphery of the piston, and wherein the large diameter fitting portion of the piston boot includes a cut-away portion at a position on the bellows portion side so that a part of the metal member is exposed to an outside.

2 . The disc brake according to claim 1 ,
wherein the large diameter fitting portion of the piston boot includes an annular protruding portion, which is formed on the inner peripheral side, and is brought into abutment against an outer peripheral surface of the piston, and wherein the annular protruding portion is formed at a position closer to the bellows portion with respect to the center of a cross section of the metal member in the axial direction of the piston.

3 . The disc brake according to claim 1 , wherein the cut-away portion is formed at a plurality of positions of the large diameter fitting portion in a circumferential direction.

4 . A piston boot which is arranged between a step portion formed on an opening end side of a cylinder including a bore portion formed in a caliper of a disc brake and a tip side of a piston accommodated in the bore portion movably in the axial direction,
the piston boot further comprising a bellows portion configured to expand and contract along with the movement of the piston, wherein the piston boot includes: a large diameter fitting portion having an annular shape and containing an annular metal member so as to be fitted to the step portion; the bellows portion which extends from the large diameter fitting portion, is increased in its diameter from the large diameter fitting portion to an outer peripheral side, and which is also deformed and extended from the large diameter fitting portion toward an inner peripheral side; and a small diameter fitting portion which is formed, at an end portion of the bellows portion, into an annular shape having a shorter diameter than that of the large diameter fitting portion so as to be fitted to an outer periphery of the piston, and wherein the large diameter fitting portion of the piston boot includes a cut-away portion at a position on the bellows portion side so that a part of the metal member is exposed to an outside.

5 . The piston boot according to claim 4 ,
wherein the large diameter fitting portion of the piston boot includes an annular protruding portion, which is formed on the inner peripheral side, and is brought into abutment against an outer peripheral surface of the piston, and wherein the annular protruding portion is formed at a position close to the bellows portion with respect to the center of a cross section of the metal member in the axial direction of the piston.

6 . The piston boot according to claim 4 , wherein the cut-away portion is formed at a plurality of positions of the large diameter fitting portion in a circumferential direction.

7 . The disc brake according to claim 2 , wherein the cut-away portion is formed at a plurality of positions of the large diameter fitting portion in a circumferential direction.

8 . The piston boot according to claim 5 , wherein the cut-away portion is formed at a plurality of positions of the large diameter fitting portion in a circumferential direction.

Assignees

• Hitachi Astemo Ltd

Inventors

• Osada Takahito
• Hayashi Shigeru
• Watanabe Shinya

Classifications

• F16D65/16 Primary

  arranged in or on the brake · CPC title

• F16D65/18 Primary

  adapted for drawing members together {, e.g. for disc brakes} · CPC title

• F16D2121/02

  Fluid pressure · CPC title

• F16J15/52

  by means of sealing bellows or diaphragms (connection of valves to inflatable elastic bodies B60C29/00) · CPC title

• F16D55/226

  in which the common actuating member is moved axially {, e.g. floating caliper disc brakes} · CPC title