Patent ID: 7004551

Claim:
A vehicular motor-driven brake device comprising: a pedal operation amount detection portion for detecting an operation amount of a brake pedal; an actuator that moves a rod in accordance with the operation amount of the brake pedal; a master cylinder having a piston which generates a master cylinder pressure that draws brake fluid from a master reservoir as a result of reciprocation caused by movement of the rod, wherein the stroke length of the piston of the master cylinder is set so as to be larger than a depression amount of the brake pedal; a wheel cylinder for generating braking force to a vehicle wheel using a wheel cylinder pressure that is generated based on the master cylinder pressure; a pressure increase valve provided in a conduit that connects the master cylinder and the wheel cylinder for regulating the master cylinder pressure so as to output the wheel cylinder pressure; a pressure decrease valve connected to the wheel cylinder for regulating the wheel cylinder pressure and discharging brake fluid in accordance with decrease of the wheel cylinder pressure; a storage reservoir for storing brake fluid discharged by the pressure decrease valve, when the wheel cylinder pressure decreases; a check valve disposed between the storage reservoir and the master cylinder for permitting flow from the storage reservoir to the master cylinder, wherein brake fluid in the storage reservoir only returns to the master cylinder from the storage reservoir via the check valve based on a pressure difference between the brake fluid pressure in the storage reservoir and the master cylinder; and a control portion for outputting respective drive signals to the actuator, the pressure increase valve and the pressure decrease valve.