Ball-ramp cam actuated disk brake

Claim 1

A disk brake apparatus for use in a tractor or the like comprising a brake disk mounted on each of a pair of differential gear shafts extending through differential bearing cases fixed to the opposite side walls of a transmission case respectively to rotatably support a differential case, a brake housing mounted on each of the opposite side walls of the transmission case and having a friction surface outside the brake disk and in facing relation thereto, and thrust producing means disposed in the housing to press the brake disk against the friction surface, the thrust producing means comprising a cam plate formed with cam grooves facing a wall of said transmission casing arranged circumferentially thereof at a specified spacing, a ball received in each cam groove respectively, and a ball retaining plate having bores for retaining each said ball therein respectively, the balls being held in the bores in point-to-point contact with the side wall of the transmission case or a seat member placed in each of the bores of the ball retaining plate, the cam plate being movable in its circumferential direction to produce a thrust in the direction to press the brake disk against the friction surface through the cooperation of the balls and the cam grooves.