| 摘要 |
A hydraulic booster comprises a boost piston (19) which receives the thrust of boost pressure generated in a boost chamber (15) to move for urging a master piston (12) of a master cylinder, an input member (17) relatively movably provided with respect to the boost piston (19), a pressure regulating device having an input directional control valve (22, 45) for allowing/cutting off communication between the boost chamber (15) and an auxiliary power source (14) and an output directional control valve (24, 46) for allowing/cutting off communication between the boost chamber (15) and a reserve tank (9), a housing (1) containing the boost piston (19), the input member (17) and the pressure regulating device in its interior, an input member positioning device for bringing the rear end of the input member (17) into contact with a stop member (51) which is anchored to the housing (1) when pedal force is zero thereby to stop rearward movement of the input member and a boost piston positioning device for balancing urging force for rearwardly pushing the boost piston (19) and that for frontwardly pushing the boost piston (19) by boost pressure when pedal force is zero thereby to stop rearward movement of the boost piston. |
