Patent ID: 8123307

Claim:
A brake boost control apparatus comprising: a brake operation member by which a driver performs a braking operation; a master cylinder which is connected with the brake operation member and produces a pressure in a brake fluid; a wheel cylinder which is installed at each wheel and produces a braking force to the wheel by the brake fluid in the master cylinder; a hydraulic pump which draws the brake fluid from the master cylinder and discharges the brake fluid to a wheel cylinder side; a master cylinder pressure detection section which is installed between the master cylinder and a suction side of the hydraulic pump and detects a pressure of the brake fluid which is produced by the operation of the brake operation member; a brake stroke amount detection section that detects a stroke amount of the brake operation member; a hydraulic pressure control section that controls a pressure of the wheel cylinder together with the hydraulic pump; a boost section which boosts the pressure of the brake fluid, produced by the master cylinder, by the hydraulic pump and increases the wheel cylinder pressure; and a control unit that controls at least one of the hydraulic pump and the hydraulic pressure control section so that the stroke amount detected by the brake stroke amount detection section under a boost operation by the boost section and the pressure detected by the master cylinder pressure detection section are maintained at a predetermined relationship, wherein: the hydraulic pressure control section has an outside gate valve which is installed between the master cylinder and a discharge side of the hydraulic pump and controls the wheel cylinder pressure, and the control unit corrects a control quantity of the hydraulic pump on the basis of a first wheel cylinder pressure that is estimated from the stroke amount detected by the brake stroke amount detection section and a second wheel cylinder pressure that is estimated from a pump operating state and an outside gate valve operating state.