Comparing boosting the high tension

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic brake device to make assisting of a braking force with boosting of a pedal stamping force using a brake booster and increase of a wheel cylinder pressure using a pump, whereby the dead point of the brake booster is sensed properly even in case a gain drop is generated in a hydraulic sensor for sensing the master cylinder pressure without bringing about cost-up and thereby assisting by the pump is performed certainly.;SOLUTION: In the region where the pedal stamping force does not exceed the dead point of a vacuum booster 14, a master cylinder pressure PM/C as assisting for the pedal stamping force is generated by the vacuum booster 14. When the dead point is exceeded, the wheel cylinder pressure PW/C is boosted using a pump 52 as a hydraulic source. Judgement whether the pedal stamping force has reached the dead point is passed on the basis of the time changing rate ΔpMC of the output signal pMC from a hydraulic sensor 62 to sense the master cylinder pressure PM/C.;COPYRIGHT: (C)2000,JPO