Patent ID: 9533665
Date: 2017-01-03
CPC Classifications: B60T

Claim:
1. A brake device for a vehicle, comprising: a reservoir for reserving operation fluid; wheel cylinders for applying braking force to respective vehicle wheels of the vehicle by a pressure of the operation fluid; a fluid pressure control valve mechanism for independently controlling the pressure of the operation fluid supplied to the respective wheel cylinders; a master cylinder for generating the pressure of the operation fluid depending on an operation of a brake pedal; at least one connection passage for connecting the master cylinder to the fluid pressure control valve mechanism; at least one shut-off valve provided in the at least one connection passage; at least one bypass passage which bypasses the at least one shutoff valve and cause the fluid pressure control valve mechanism to be in communication with the reservoir; at least one one-way valve provided in the at least one bypass passage, the at least one one-way valve allowing only a flow of the operation fluid from the reservoir to the fluid pressure control valve mechanism; a power-driven type fluid pressure source driven by a predetermined power to supply, to the fluid pressure control valve mechanism, the operation fluid having the pressure depending on the operation of the brake pedal; and an electronic control unit for controlling an operation of the fluid pressure control valve mechanism and an operation of the power-driven type fluid pressure source, the electronic control unit is programmed: to maintain a state of the at least one shut-off valve at a state for shutting off a flow of the operation fluid from the master cylinder to the fluid pressure control valve mechanism when the brake pedal is operated; and to maintain the state of the at least one shut-off valve at a state for allowing the flow of the operation fluid from the master cylinder to the fluid pressure control valve mechanism when the brake pedal is not operated, wherein the master cylinder includes: at least one pressurizing chamber in which the operation fluid is pressurized by at least one pressurizing piston which moves in conjunction with the operation of the brake pedal; and at least one atmospheric pressure chamber for maintaining the pressure of the operation fluid at the atmospheric pressure, the at least one pressurizing chamber becomes in communication with the reservoir when the brake pedal is not operated, the at least one atmospheric pressure chamber is in communication with the reservoir regardless of whether the brake pedal is operated, the at least one connection passage includes the at least one pressurizing chamber, and the at least one bypass passage includes the at least one atmospheric chamber.