| 摘要 |
PROBLEM TO BE SOLVED: To precisely adjust a pad clearance in an electrically driven disc brake device by absorbing a backlash in a screw transmission mechanism during a release of braking. SOLUTION: In an electrically driven disc brake 2 is of a caliper-floating type, the rotation of a rotor 22 in a DC servo-motor 21 is converted into a rectilinear motion of a piston 9 by means of a ball and screw mechanism including a nut member 16 a thread groove in the piston 9 and steel balls 19, so as to press brake pads 12, 13 against a disc rotor 8 so as to effect a braking force. In order to release braking, the DC motor 21 is rotated from a braking position to a retracted position in the retracting position of the piston 9, and is then rotated from the retracted position to an original position in the extending direction of the piston 9 so as to adjust a pad clearance. With this arrangement, the pad clearance can be precisely adjusted while the backlash of the ball screw mechanism is decreased. |
