Abstract: A brake rotor for use in a vehicle disc brake assembly includes an inner mounting flange and an outer annular friction disc connected together by a circumferential hat. The inner mounting flange is formed having a center pilot hole and a plurality of lug bolt receiving holes equally spaced circumferentially about the pilot hole. The outer annular friction disc includes a pair of annular friction plates which are connected together in a spaced apart relationship by a plurality of fins spaced circumferentially around the friction disc. Each successive pair of the fins defines a cooling passageway between the friction plates. Each of the fins extends in a generally radial direction and includes an innermost end, an outermost end, and a pair of spaced apart outer side wall surfaces. Each fin defines a symmetric center axis between the outermost end and the innermost end thereof.

Abstract: An improved vehicle disc brake rotor is disclosed having a unique vented design. The rotor includes a pair of brake friction plates maintained in spaced relationship by a plurality of radially extending fins. Each friction plate is tapered radially from the outer peripheral end to the inner peripheral end thereof such that the friction plates have an increased cross-sectional thickness at the outer end. In addition, each fin is "blended" into the friction plates. Such a configuration increases the heat capacity and stiffness at the outer end of the rotor. A separate radially extending cooling air passageway is defined between each pair of the fins. The air passageway is configured to define a cross-sectional area which is substantially uniform throughout its entire length. This results in the velocity of cooling air being increased as it flows through the passageway, thus improving cooling efficiency.

Abstract: An apparatus and method for measuring the circularity of a brake drum while the brake drum is mounted upon a vehicle. The apparatus includes a linear voltage displacement transducer mounted upon a stationary portion of the vehicle. The transducer senses the variation of the braking surface and generates a signal proportional thereto. The apparatus also includes an optical encoder that generates a signal indicative of the angular position of the drum. The transducer and encoder are connected to a central processing unit which receives the transducer and encoder signals. The drum is rotated through a plurality of complete revolutions while the central processing unit combines the transducer and encoder signals to generate a set of data points. The central processing unit operates upon the data points to determine the circularity of the braking surface.

Abstract: A disc brake piston is formed from a stamping operation and is preferably constructed from stainless steel. The piston includes a hollow cylindrical body having a closed end and an open end. In one preferred embodiment, the open end is provided with a radially outwardly extending flange which defines an annular abutment surface for engaging a backing plate of a disc brake shoe. An integral boot groove is formed in the cylindrical body adjacent the open end thereof, and produces a raised portion on an inner surface of the body portion directly opposite the groove. This results in the piston having a substantially uniform wall thickness throughout the entire length of the cylindrical body. Also, the piston can include a dome-shaped recess formed in the closed end thereof, which can be provided with radial strengthening ribs.

Abstract: A composite rotor and an improved hat section structure therefor, wherein the hat section is formed to include a rim having a non-planar, rotor-engaging periphery. A rotor discoid is then cast around the hat section so that a portion of the rotor discoid encloses or covers at least the non-planar periphery of the rim and bonds thereto. Composite rotors so produced have been shown to have exceptionally uniform stress distribution during vehicle braking.