| 摘要 |
<P>PROBLEM TO BE SOLVED: To restrain generation of operation noise accompanied by operation of a pressure reduction valve in a hydraulic booster wherein the pressure reduction valve opening and closing in accordance with retreating and advancing of a control piston actuating reaction force based on the hydraulic pressure of a booster hydraulic chamber along the retreating direction through a reaction force piston intervenes between a release chamber and a booster hydraulic control chamber. <P>SOLUTION: A reaction piston 92 is provided with an insertion hole 143 communicating a front end with the booster hydraulic control chamber 130, a communication hole 144 communicating with a release chamber 135, and a flange shaped pressure reduction valve seat 146 protruding to the radial inward direction between the insertion hole 143 and an axial hole part 144a. A pressure reduction valve element 147 of the pressure reduction valve 117 is arranged in front of the reaction force piston 92, the rearmost position is regulated, and the pressure reduction valve element 147 is spring-energized to the rear. A rear part of the pressure reduction valve element 147 is inserted into the insertion hole 143 so as to form an annular orifice 148 with the reaction force piston 92 in front of the pressure reduction valve seat 146. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
