Patent ID: 7299905

Claim:
An electric disc brake apparatus comprising: a caliper comprising a piston that pushes a pair of brake pads opposing each other on either side of a disc rotor toward the disc rotor, a motor that moves the piston via a rotation-linear movement conversion mechanism, the motor being operated by an electric current, a claw wheel provided to rotate along with rotation of the motor, an engaging claw disposed on the outer periphery of the claw wheel so as to engage with or separate from the claw wheel, and an actuator that causes the engaging claw to engage with or separate from the claw wheel, wherein the claw wheel, the engaging claw and the actuator constitute a holding mechanism for a parking brake which maintains thrust of the piston generated by the motor; a controller that controls the motor and the actuator; and an electric current sensor that detects the electric current flowing through the motor, wherein the controller comprises an operating condition detector which diagnoses operating conditions of the holding mechanism, and the operating condition detector determines, after the controller transmits a command for releasing the engaging claw from the claw wheel, that release of the engaging claw from the claw wheel has failed, if the current value from the electric current sensor, which is detected when the motor is operated to reduce the thrust of the piston, exceeds a predetermined reference value.