Patent ID: 8616347

Claim:
A pneumatic disc brake for use with a brake disc to apply brake pads against the brake disc, the disc brake comprising: a caliper configured to straddle the brake disc; a brake application unit arranged in the caliper, the brake application unit including a brake lever operable by a plunger of a brake cylinder to rotate about an eccentric axis in order to displace a brake-application-side brake pad against the brake disc; a self-energizing mechanism having a self-energizing factor selected such that the disc brake automatically releases after a braking event; a brake ram coupled to the brake-application-side brake pad; and first and second pressure rams, each pressure ram being arranged in parallel and at a distance on each side of the brake ram, each pressure ram being supported at one end on the caliper and at another end via a pressure ram bearing ball on the brake pad; a guide plate operatively configured to hold the pressure rams, the guide plate being mounted to be displaceable in a brake carrier in an axial direction relative to the brake disc, wherein the brake lever is supported at least on at least one spherical bearing element mounted in the caliper and forming an eccentric rotational axis, the brake lever pressing against a brake lever bearing ball located closer to a plunger engagement end of the brake lever than the at least one spherical bearing element; and the brake lever bearing ball is positioned in the brake ram, the at least one spherical bearing element comprises two bearing elements that are operatively configured to support the brake lever, the brake lever bearing ball being arranged at a location between the two bearing elements, the brake lever comprises spherical caps configured to receive each of the two bearing elements and a bulge configured to receive the brake lever bearing ball, and the brake application unit is operatively configured such that when the self-energizing mechanism's self-energizing factor is selected such that the disc brake automatically releases after every braking event, a rotational lever transmission ratio is in a range of about 7:1 to 10:1.