Abstract: A disc brake caliper including a brake piston movably arranged therein. The brake piston is sealed in relation to the brake cylinder by a sealing ring, which is arranged in a circumferential annular groove of the brake cylinder. The sealing ring functions to retract the brake piston in the brake cylinder after a braking operation in order to provide a clearance between a brake shoe and a brake disc. According to the present invention, the annular groove includes a recess, which is arranged in the area of transition between a groove wall and the cylinder surface . The contour line, which defines the cross-section of the recess, starting from the groove wall of the annular groove, passes from a convexly curved portion over into a concavely curved portion. This permits ensuring an unchangingly constant clearance between the brake shoe and the brake disc roughly irrespective of the hydraulic pressure.

Abstract: A brake shoe for disc brakes comprises a pad back plate which, on a first face thereof, is provided with a friction pad and, on a second face thereof, has a projection to which a retaining spring is fixed to prevent rotation of the retaining spring relative to the pad back plate. The projection extends through a non-circular opening in the retaining spring and comes into intimate contact with the opening when deformed radially by the application of an axial force to the projection to produce a form-lock which prevents the retaining spring from rotating relative to the pad back plate.

Abstract: A floating caliper disc brake comprises a stationary brake carrier including two carrier arms protruding beyond the outer rim of a brake disc. Disposed on either side of the brake disc are brake shoes that are displaceably supported on the carrier arms and embraced by a floating caliper guided in an axially displaceable manner on the brake carrier. A spring assembly, acting on the brake shoes in the brake releasing direction after braking, creates the clearance between the brake shoes and the brake disc. The spring assembly is provided with at least one expander spring which is non-displaceably secured to a section of the carrier arm located above the outer rim of the brake disc. The expander spring is provided with at least two spring struts which, in the brake releasing direction, are in resilient abutment with the back plates of the brake shoes and thus insure a uniform distribution of the brake clearance among the brake shoes.

Abstract: A disc brake having a brake caliper provided with a hydraulic actuating device including a brake cylinder and a brake piston. The brake piston is sealed relative to the brake cylinder by way of a sealing ring arranged in a surrounding annular groove of the brake cylinder. The annular groove is provided with a recess arranged in the transitional area between a groove wall and the cylinder surface. The recess is confined by at least three surrounding conical surfaces whose angles towards the cylinder surface increase progressively, starting from the surface which borders on the cylinder surface up to the surface which borders on the groove wall.