BRAKING SYSTEM HAVING VACUUM BOOSTER WHOSE BOOSTING RATIO ISLOWERED AT FIXED TRANSITION POINT AT WHICH WHEEL CYLINDER PRESSURE INCREASE IS INITIATED

摘要

Vehicle braking system including a vacuum booster for transmitting a boosted brake operating force to a master cylinder such that the boosting ratio is reduced at a fixed transition point before the boosting limit point is reached, a brake having a wheel brake cylinder connected through a fluid passage to a master cylinder serving as a first hydraulic pressure source, for braking a wheel, and a pressure increasing device having a second hydraulic pressure source connected to the fluid passage, and wherein the pressure increasing device initiating a pressure increasing operation, when the brake operating force has increased to the transition point, to increase the wheel cylinder pressure to be higher than the master cylinder pressure, by using the second hydraulic pressure source.