Patent ID: 7331432

Claim:
A disk brake apparatus comprising: a cylinder bore that is formed in a caliper body so as to extend in a cylinder axis and comprising an opening at a front side; and a bottom wall at a bottom side; a piston accommodated in the cylinder bore at the front side of the cylinder bore; a thrust conversion mechanism provided at the bottom side of the cylinder bore and comprises: a fixed-side cam plate fitted to the bottom wall of the cylinder bore; a cam shaft provided so as to rotatably penetrate the bottom wall of the cylinder bore and the fixed-side cam plate and also to be movable in the cylinder axis; a driving-side cam plate provided on the cam shaft at the front side of the cylinder bore; ramp recesses respectively formed on the driving-side cam plate and the fixed-side cam plate so as to oppose to each other; and cam bearings accommodated in the ramp recesses; an adjuster that is provided between the thrust conversion mechanism and the piston and comprises: an adjusting nut; an adjusting bolt; a thrust transfer plate provided on either of the adjusting nut and the adjusting bolt at the bottom side of the cylinder so as to oppose to the driving-side cam plate; and a cam spring that biases the thrust transfer plate toward the driving-side cam plate; and a housing accommodating the fixed-side cam plate, the driving side cam plate, the thrust transfer plate and the cam spring, wherein a fastening groove is provided on a bottom surface of the fixed-side cam plate, the bottom surface being opposed to the bottom wall of the cylinder bore, a fastening piece is provided on the housing at the bottom side of the cylinder bore so as to fit to the fastening groove, the cylinder bore comprising an axial groove on an inner peripheral surface thereof at the bottom side, and the fixed-side cam plate comprising an anti-rotation projection projected from an outer circumferential surface thereof so as to engage with the axial groove of the cylinder bore.