Disc brake assembly and guide structure therefor

Claim 1

A disc brake assembly comprising, in combination: a disc mounted to rotate with an associated wheel; a pair of brake pads arranged on opposite sides of said disc and adapted to be brought into contact therewith to frictionally brake rotation of said wheel; a piston adapted to urge one of said brake pads against one side of said disc in response to braking fluid pressure applied thereto: a cylinder operatively associated with said piston adapted to urge the other of said brake pads against the opposite side of said disc under the influence of a reaction force created in said cylinder between said piston and said cylinder by application therein of said braking fluid pressure; a torque receiving member mounted to receive braking torque developed in said pads by braking engagement thereof against said disc to prevent relative movement of said pads circumferentially of said disc; guide means for guiding movement between said piston and said cylinder during application of said braking fluid pressure, said guide means comprising boss means formed on said cylinder and fixed relative thereto, pin means extending in sliding engagement within said boss means for effecting guided relative movement therebetween, means detachably fixing said pin means to said torque receiving member, and boot means formed of resilient material extending between said boss means and said pin means to form a resilient external seal for said guide means against contaminating materials; said guide means operating between said cylinder and said torque receiving means to guide movement of said cylinder in directions normal to said disc by the guiding engagement between said pin means and said boss means; said boss means comprising a generally open-ended cylindrical configuration encircling said pin means with an annular gap being formed between said pin means and said boss means, said boot means comprising a pair of resilient boots each formed at one of said open ends of said boss means, each of said resilient boots including a cylindrical root portion extending into said annular gap with the root portion of one of said boots being in a spaced apart relationship relative to the root portion of the other of said boots to define therebetween within said annular gap an annular clearance forming a reservoir for lubricating material; means defining on said boss means an inner wall thereof having formed therein annular grooves; and radial flanges formed on each of said cylindrical root portions of said boots; said boots being fixed relative to said boss means with said radial flanges engaged within said annular grooves; said pin means being arranged in axial sliding engagement within said cylindrical root portions of said resilient boots, with lubricating material within said reservoir operating to lubricate said axial sliding engagement between said pin means and said cylindrical root portions.