Air cooled piston cap assembly

摘要

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.

主权项

1. A piston cap assembly particularly adapted for use in a disc brake caliper, comprising:
a piston body slidably movable within a caliper bore along a central axis and having an end in contact with hydraulic fluid, a piston cap having a retention portion resting on an annular ledge within the piston body, a contact portion opposite from the retention portion that contacts a brake pad assembly, and an intermediate portion connecting the retention portion with the contact portion, wherein exterior surfaces of the contact portion, intermediate portion and retention portion define a heat transfer path between said brake lining and piston body, and wherein an air gap is defined between a top edge of the piston body and an undersurface of the contact portion of the piston cap allowing air to circulate over the heat transfer path, the heat transfer path between said brake lining and said piston body extended by the shape of the piston cap so that it is longer than a linear path parallel to said axis between the contact portion and the piston body, wherein the contact portion of the piston cap includes a central recess or opening such that only an outer periphery of the contact portion contacts a brake lining, and wherein the intermediate portion is formed from solid metal and functions as a heat sink for heat received from the contact portion of the piston cap.