Patent ID: 6851762

Claim:
A brake fluid pressure control device for a vehicle comprising: a master cylinder for generating a first brake fluid pressure according to an operating condition of a brake pedal; a wheel cylinder to which a second brake fluid pressure is applied for brake control; a hydraulic booster for producing the second brake fluid pressure that is higher than the first brake fluid pressure; a main pipeline connecting the master cylinder to the wheel cylinder via the hydraulic booster; and a fluid pressure regulating unit whose one end is connected to the hydraulic booster and whose other end is connected to the main pipeline between the master cylinder and the hydraulic booster, the fluid pressure regulating unit holding a pressure difference between the first and second brake fluid pressure to a rated value, the rated value variable according to the operating condition of the brake pedal; wherein the hydraulic booster has a pump unit having intake and discharge ports, a flow amount amplifying unit, first and second pipelines through which the flow amount amplifying unit and the pump unit are able to communicate with the main pipeline on a side of the wheel cylinder, respectively, and a flow amount amplification changing unit, the pump unit is operative, always when the brake pedal is engaged, and during normal braking, to draw, via the intake port, brake fluid from the main pipeline between the master cylinder and the fluid pressure regulating unit and to compress and discharge via the discharge port the brake fluid to the second pipeline, the flow amount amplifying unit to which the brake fluid discharged from the pump unit is supplied from the second pipeline and from which the brake fluid whose amount is larger than that supplied thereto is discharged to the first pipeline, and the flow amount amplification changing unit operative to select one of the first and second pipelines as a pressurizing path through which the brake fluid from the hydraulic booster is discharged to the main pipeline on a side of the wheel cylinder for producing the second brake fluid pressure and to always selected first pipeline for a given period immediately after the brake pedal is engaged.