Disk brakes for utility vehicles with these features are known from EP 0 614 024 B1 and DE 42 30 005 A1. A brake caliper reaching over the brake disk and the brake pads holds an application device which can be actuated by a force member, e.g. a compressed-air cylinder, flanged onto the outside. A central component of the application device is a brake lever which is mounted pivotably in the brake caliper. This is composed of a lever arm, which supports the force member, and an application shaft. The application shaft at one end rests rotationally movably against the brake caliper housing, and at the other end rests rotationally movably against a pressure piece which is arranged so as to be longitudinally movable in the brake caliper and works directly or indirectly against the inner brake pad on the application side.
Usually, such disk brakes are designed symmetrically in the circumferential direction, since in particular pressure is applied to the two brake pads, and in particular to the inner brake pad on the application side, symmetrically in relation to the circumferential direction. Vehicles equipped with such brakes travel in everyday use almost exclusively in one direction, while the other direction of travel—normally assumed on reversing—occurs very rarely. The brake caliper must however press on the brake pads as evenly as possible, even though the direction of travel is always the same. This is because only in this case is the surface temperature the same across the entire brake pad. Local increases in pressure on the brake pad lead to temperature rises, associated with a reduction in the performance of the brakes and increased wear on the brake pad.
The problem of geometrically induced oblique wear on disk brakes (so-called circumferential oblique wear) is therefore known. For example, in the single-cylinder disk brake according to DE 42 30 005 A1, as a compensation measure it is proposed to configure the pressure transfer face acting on the inner brake pad at a slight angle or wedge-shaped, so that viewed in the circumferential direction, the pressure distribution is asymmetrical.
In the field of hydraulically actuated disk brakes in which the force member is usually a cylindrical hydraulic piston, previously efforts have focused on arranging the hydraulic piston offset tangentially in the brake caliper. The brake pressure exerted by the piston is not then applied to the geometric center of the brake pad, but its focal point is a geometric location which is slightly offset forward in the circumferential direction of the brake disk. Hydraulically actuated disk brakes with these features are known e.g. from DE 35 40 810 C1 or U.S. Pat. No. 4,533,025. The basic concept of simply arranging the piston transmitting the application force offset in the tangential direction cannot however easily be transferred to a disk brake operated by compressed air, with a brake lever arranged pivotably in the brake caliper housing.
The object of the invention is therefore to find measures which, above all in a compressed-air operated disk brake of the type cited initially, compensate for the geometrically induced oblique wear of the brake pads.
USPTO Backgrounds
USPTO Backgrounds