Disk brake

摘要

A disk brake including a simplified structure for retaining the braking force of a parking brake. The disk brake is equipped with a piston holding mechanism having a ball-and-ramp mechanism in which balls are moved by rotation transmitted from a motor, causing a rotary-rectilinear ramp to press a piston. The rotary-rectilinear ramp has an external thread engaged with an internal thread formed on a base nut that is immovable in a rotor axis direction relative to a caliper body. The external thread, when a force is applied thereto from the piston in the rotor axis direction, can retain the position of the rotary-rectilinear ramp in the rotor axis direction. Thus, the structure for retaining the braking force of the parking brake can be simplified to improve production efficiency.

主权项

1. A disk brake comprising:
a pair of pads disposed at opposite sides, respectively, of a rotor to face each other across the rotor in a direction of an axis of the rotor; a piston pressing one of the pair of pads against the rotor; a caliper body having a cylinder in which the piston is movably disposed; an electric motor provided on the caliper body; and a parking brake mechanism provided in the caliper body to propel and hold the piston in a braking position; the parking brake mechanism having:
a ball-and-ramp mechanism;a rotating member rotatably provided in a rotor diametrical direction of a ball groove of the ball-and-ramp mechanism; anda screw mechanism,wherein the ball-and-ramp mechanism has a first ramp which can be rotated and rectilinearly moved, a second ramp, and a ball interposed between the first ramp and the second ramp, wherein the screw mechanism comprises a first thread provided on the first ramp and a second thread provided on the rotating member and engaged with the first thread, and wherein rotation of the electric motor causes the ball-and-ramp mechanism and the screw mechanism to move the piston to the braking position, and the piston is held in the braking position by the first thread and the second thread of the screw mechanism.