Brake adjuster

摘要

A brake adjuster is provided for a vehicle brake (10) such as for heavy duty vehicle. The brake adjuster includes a brake module (76) that produces an electrical signal for adjusting the vehicle brake. The heavy duty vehicle brake typically includes a pair of pistons (36) each having first (42) and second (44) portions that are movable relative to one another. A friction element or brake pad (16) is arranged proximate to the second portion and is movable from a desired position (P) to a worn position (W) as the brake pads wear during operation of the vehicle. In one embodiment of the present invention, the first and second portions are slip fit within a sleeve assembly (38). At least one adjustment member (68) is arranged between the first and second portions. The adjustment member is constructed from a material which expands in response to an electrical signal, such as a magnetostrictive or a piezoelectric material. The adjustment member moves the second portion relative to the first portion and repositions the brake pads from the worn position to the desired position. In another embodiment, the first and second portions are threaded to one another and movable rotationally relative to one another to adjust the length of the piston. The first portions of the pistons include a plurality of teeth (52) about the outer face. A gear (54) is arranged between the pistons and coupled the teeth of the first portions together. An electric actuator (82) has a driven member (84) that is coupled with at least a portion of one of the piston's teeth to rotate the first and second portions relative to one another to increase the length of the piston and move the brake pad from the worn position to the desired position.