Patent ID: 8511758

Claim:
A brake system, comprising: a master cylinder for generating a brake hydraulic pressure by movement of a piston; a booster for moving the piston of the master cylinder; a hydraulic pressure detector for detecting the brake hydraulic pressure generated in the master cylinder; a valve mechanism provided so as to be capable of bringing the master cylinder and wheel cylinders into communication with each other and interrupting the communication between the master cylinder and the wheel cylinders; and a control device connected to the hydraulic pressure detector, for controlling the valve mechanism and the booster, wherein: the booster includes: an input member moved forward and backward by an operation of a brake pedal; an assist member provided so as to be movable relative to the input member, the assist member being moved forward and backward by an electric actuator to move the piston of the master cylinder; and a moved position detector for detecting a moved position of the assist member; and when detecting a control origin position for the moved position detector, the control device interrupts the communication between the master cylinder and the wheel cylinders by the valve mechanism and then moves the assist member forward by the electric actuator in a direction in which a hydraulic pressure is generated, to thereby set, as the control origin position, a position obtained by moving backward by a predetermined amount a position at a time of generation of hydraulic pressure, the position at a time of generation of hydraulic pressure being detected by the moved position detector upon detection of the generation of the hydraulic pressure by the hydraulic pressure detector.