Adjuster mechanism for a disc brake

摘要

A caliper assembly for a disc brake having opposed friction pads (28) at least one of which may be axially displaced into engagement with a rotor (30) rotatably maintained about an axis and drivingly associated with a vehicle wheel. The caliper assembly includes an eccentric (15) which is bearingly carried in the caliper housing and rotatably engaged to a reciprocating element (20) to convert rotation of the eccentric (15) into a reciprocating motion. The eccentric is rotated by a lever (16) associated with an actuation means such as an air actuated cylinder. The reciprocating element (20) defines a first face and has first and second annularly displaced axially extending bores. Adjustable length sleeve assemblies (22,52) are located in the first and second bores with portions extending axially therefrom and connected to a load plate (24). The load plate defines an annularly extending axially displaced second face which may be axially positioned relative to the first face by adjustment of the sleeve assemblies (22,52). The sleeve assemblies each feature a first cylindrical member having a first end defining a head (60) and a second end having threads defined on the external surface thereof. A second cylindrical member having an opening defining a bore has threads defined on the internal surface thereof which cooperate with respective threads defined on the external surface of the first cylindrical member. The second cylindrical member includes a first end portion having an external surface which is rotatably received within one of the bores of the reciprocating element and a second opposing end defining a radially extending head located thereon defining a limit of axial displacement toward the first face of the load plate. The second cylindrical member is drivingly associated with an adjusting gear that may be used to define a coordinated relative rotary position between the first and second cylindrical members. Controlling the respective relative rotary position of the first and second cylinders is the technique by which the axially extending dimension of the adjustable length sleeve assemblies (22,52) is accomplished. The relative rotational position of the adjusting sleeve components establishes the dimensional relationship between the first face of the reciprocating element and the second face of the load plate (24) thereby accomplishing definition of the working clearance between the friction pad (28) and rotor (30). The relative rotational position may be achieved by harnessing excess angular displacement of the eccentric (15) which occurs when friction pad wear produces excess rotor to friction pad clearance and using this displacement to control the length of the sleeve assemblies (22,52). Such a mechanism utilizes a lever which is angularly displaced by movement of the eccentric. The lever engages a second lever which causes relative rotation between the cylindrical members of the sleeve assemblies. A torque limiting clutch is used to facilitate a torque override for de-adjust mode, and a one-way clutch assures maintenance of adjusted rotary positions. <IMAGE>