| 摘要 |
PURPOSE:To provide a large hysteresis by a simple constitution by making the inner circumferential edge of the edge surface of a valve body which is brought into contact with a reaction disk to be a tapered surface where the front side is radially expanding. CONSTITUTION:From the servo-balanced condition where a breather valve provided with a valve mechanism and a vacuum valve are closed, a valve plunger 2 advances, and the position of the tip surface 2a of the valve plunger 2 is on the upper side when the breather valve is opened. From the servo- balanced condition, the valve plunger 2 sets back, and the position of the tip surface 2a of the valve plunger 2 is on the lower side when the vacuum valve is opened. A tapered surface 1d is formed so as to include the position of the tip surface 2a of the valve plunger 2 when the breather valve is opened and the position of the tip surface 2a of the valve plunger 2 when the vacuum valve is opened. In the servo-balanced region after a brake booster is started to operate, the servo-ratio can be changed when the brake pedal is operated, and when the brake is released, obtaining a large hysteresis. |
