Disc brake for a motor vehicle, having a sealing arrangement designed for an electronic parking brake

Patent metadata

Field	Value
Publication number	US-9919686-B2
Application number	US-201414907895-A
Country	US
Kind code	B2
Filing date	Jul 22, 2014
Priority date	Aug 1, 2013
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A disc brake for a motor vehicle, wherein it is possible to displace the actuating piston in the housing both by hydraulic pressure activation of a hydraulic chamber formed in the housing and via a mechanical actuator, wherein the sealing ring is accommodated in an annular groove formed in the housing. Provision is made here for the annular groove to have a groove floor, which runs substantially parallel to the longitudinal axis of the piston, and two groove walls, which adjoin the groove floor, wherein—as seen in the direction of the longitudinal axis of the piston—a first groove wall is directed away from the hydraulic chamber and a second groove wall is directed towards the hydraulic chamber, wherein the first groove wall merges into the groove floor via a rounded or bevelled transition region at a varying distance from the longitudinal axis of the piston.

First claim

The invention claimed is:

1. A disc brake for an automotive vehicle, wherein the disc brake comprises a housing, a brake disc rotatable relative to the housing, at least one friction pad, and at least one actuation device, which is formed to effect a relative movement between the brake disc and the friction pad such that the friction pad can be brought into contact with the brake disc, wherein the actuation device has at least one actuating piston movable along a piston longitudinal axis, which actuating piston is guided in a hydraulically sealing manner within the housing by means of a sealing arrangement having a sealing ring, wherein the actuating piston is movable within the housing both by means of applying a hydraulic pressure of a hydraulic chamber provided within the housing and by means of a mechanical actuator, wherein the sealing ring is taken up in an annular groove formed in the housing, wherein the annular groove comprises a groove floor extending parallel to the piston longitudinal axis as well as two groove walls adjacent to the groove floor, wherein—as viewed in the direction of the piston longitudinal axis—a first groove wall is directed away from the hydraulic chamber and a second groove wall is directed towards the hydraulic chamber, wherein the first groove wall merges via a rounded transition area with a varying distance to the piston longitudinal axis into the groove floor and the second groove wall merges via a bevelled transition area with a varying distance to the piston longitudinal axis into the groove floor, wherein the transition area has a profile that is substantially in the shape of a circular arc as viewed in a section containing the axis, and wherein the radius of the profile in the shape of the circular arc is in the range between 0.5 and 2 mm.

2. The disc brake according to claim 1 , wherein the transition area is formed as an oblique transition surface, which extends at an angle of between 35 and 55° relative to the groove floor.

3. The disc brake according to claim 1 , wherein the first groove wall or/and the second groove wall runs radially within the transition area substantially perpendicular to the piston longitudinal axis.

4. The disc brake according to claim 1 , wherein the second groove wall runs out in its radially inner area in a surface section, which deviates from the perpendicular progression to piston longitudinal axis.

5. The disc brake according to claim 4 , wherein the surface section is formed by a bevel, which encloses an angle of between 15° and 45° with the second groove wall.

6. The disc brake according to claim 4 , wherein the surface section extends over an area of 30% to 70% of the radial height of the annular groove.

7. The disc brake according to claim 1 , wherein a transition surface is provided between the groove floor and the second groove wall.

8. The disc brake according to claim 7 , wherein the transition surface is formed as a bevel, which runs at an angle of 30° to 50° relative to the groove floor.

9. The disc brake according to claim 1 , wherein the sealing ring is formed with a larger outer diameter than the inner diameter of the annular groove.

10. The disc brake according to claim 9 , wherein a volume of the cavity enclosed by the annular groove is greater than a volume of the sealing ring.

11. The disc brake according to claim 1 , wherein the mechanical actuator is formed as a component of an electrically activatable parking brake.

12. The disc brake according to claim 9 , wherein the outer diameter of the sealing ring is formed with a radial oversize of 0.5-1.2 mm.

13. The disc brake according to claim 10 , wherein the volume of the cavity enclosed by the annular groove is greater than the volume of the sealing ring by a factor of 1.1 to 1.5.

14. A housing for a disc brake comprising:
a cylindrical piston receptacle opening forming a hydraulic chamber, in which opening an actuating piston of an actuation device can be taken up, which piston is movable along a piston longitudinal axis, wherein the actuation device is formed to effect a relative movement between a brake disc and a friction pad, so that the friction pad can be brought into contact with the brake disc, wherein the actuating piston is guided movably within the housing in a hydraulically sealing manner by means of a sealing arrangement with a sealing ring and wherein the actuating piston is movable within the housing both by applying hydraulic pressure of the hydraulic chamber and by means of a mechanical actuator, wherein the sealing ring can be fitted in an annular groove formed in the housing, wherein the annular groove has a groove floor running parallel to the piston longitudinal axis as well as two groove walls adjacent to the groove floor, wherein—as viewed in the direction of the piston longitudinal axis—a first groove wall is directed away from the hydraulic chamber and a second groove wall is directed towards the hydraulic chamber, wherein the first groove wall merges via a rounded transition area with a varying distance to the piston longitudinal axis into the groove floor and the second groove wall merges via a bevelled transition area with a varying distance to the piston longitudinal axis into the groove floor, wherein the transition area has a profile that is substantially in the shape of a circular arc as viewed in a section containing the axis, and wherein the radius of the profile in the shape of the circular arc is in the range between 0.5 and 2 mm.

Assignees

• Lucas Automotive Gmbh

Inventors

• Stahl Peter
• Kuhnert Boris
• Damrau Christian
• Tharr Christian
• Podzuweit Dietrich
• Heinemann Maria
• Brandt Martin
• Dang Nong
• Schog Michael

Classifications

• F16D65/18 Primary

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

• F16D2127/02

  Release mechanisms · CPC title

• B60T1/065 Primary

  employing disc (B60T1/062 takes precedence) · CPC title

• F16D2123/00

  Multiple operation forces · CPC title

• F16D2121/02

  Fluid pressure · CPC title