Patent ID: 6666530
Filing Date: 2003-12-23
Classification: B60T,F02D

Abstract:
A vacuum booster apparatus adapted to be used for a brake apparatus provided in a vehicle having an internal combustion engine, said vacuum booster apparatus comprising:a vacuum booster having a first pressure chamber and a second pressure chamber, said first pressure chamber being connected to an intake pipe of said engine on a downstream side of an intake passage opening and closing valve, said second pressure chamber being selectively connectable to one of said first pressure chamber and atmosphere, said vacuum booster boosting an operating force applied to a brake operating member operated by a driver based on a pressure difference between said first pressure chamber and said second pressure chamber; and a throttle-opening-degree control device controlling a negative pressure in said first pressure chamber by controlling a degree of opening of said intake passage opening and closing valve, wherein said throttle opening degree control device includes large-change-time opening degree decreasing means for decreasing the degree of opening of said intake passage opening and closing valve as a rate of increase in an operating-force relating amount related to the operating force applied to said brake operating member by the driver is increased.