| 摘要 |
PURPOSE:To simplify the structure to open the valve in such a way that opening and closing of a valve at an inlet port which is conducted to an accumulator is constituted to be done by a body to more in the diametral direction which is arranged at the outer periphery of a power piston. CONSTITUTION:When a brake pedal 68 is stepped on, an input rod 67 moves to the left, and a spool 18 is moved to the left through an inner shaft 60 of an operating rod 6. By doing as this, the shoulder part 32 of a land 28 comes near to a shoulder part 22, an opening area of a throttle valve 39 is perceived, working oil flow from a groove 20 to a groove 25 is limited. At the same time, when a return valve 41 is closed with left movement of the spool 18, a control valve 40 is closed. Oil pressure which has got into a boost chamber 37 thrusts a power piston to the left, and the vehicle is braked. When the brake pedal 68 is further stepped on, finally the throttle valve 39 is entirely closed, and the vehicle is suddenly braked. |
