Air cooled piston cap assembly

Abstract

An air-cooled piston cap assembly is provided for use in a disc brake caliper that includes a piston cap, and a piston body having a proximal end and a distal end which is slidably movable within a caliper bore along an axis. The piston cap includes a retention portion mounted within the distal end of the piston body, a contact portion located opposite from the retention portion that contacts a brake pad assembly, and an intermediate portion connecting the retention portion with the contact portion. The outer surface of the intermediate portion defines an extended heat exchange path between the contact portion and the retention portion, and may for example hourglass-shaped. An air gap is provided between a top edge of the piston body and an undersurface of the contact portion of the piston cap that allows air to circulate over the extended heat transfer path defined by the outer surface of the contact portion and intermediate portion to cool the cap from frictional heat generated during braking. The contact portion of the piston cap is shaped such that only a part of the surface of the contact portion contacts the brake pad assembly to advantageously reduce both conductive heat transfer and noise during a braking operation.