Patent ID: 9499147
Filing Date: 2016-11-22
CPC Classification: B60T

Claim Text:
1. A vehicle brake system for generating a friction braking force at a wheel of a vehicle by a friction brake device by supplying a wheel cylinder of the friction brake device with a brake fluid, comprising: a master cylinder connected to the wheel cylinder; an output piston provided in the master cylinder and slidably movable therein, the output piston being driven by a hydraulic pressure in a servo chamber defined in the master cylinder and variably changing a volume of a master chamber filled with the brake fluid to be supplied to the wheel cylinder; an input piston provided in the master cylinder at a front of the output piston and slidably movable therein, the input piston defining a separation chamber to be filled with the brake fluid in the master cylinder between the output piston and the input piston, the output piston being operable with an operation of a brake operating member; a separation lock valve for closing or opening the separation chamber; a servo pressure generating portion for generating a servo pressure in the servo chamber; a fade state judging portion for judging whether the friction brake device is in a fade state or not; a friction brake control portion for closing the separation chamber by the separation lock valve when the friction brake device is judged to be in the fade state by the fade state judging portion; and wherein the friction brake control portion executes a pre-charge control which generates a pre-charge pressure in the servo chamber by the servo pressure generating portion when the friction brake device is judged to be in the fade state by the fade state judging portion and after the pre-charge control, closes the separation lock valve, and wherein the pre-charge pressure is a pressure for advancing the output piston with a predetermined distance relative to the input piston.