| 摘要 |
<P>PROBLEM TO BE SOLVED: To achieve enhancement of initial responsiveness of a pressure increase valve and to also enhance responsiveness of the pressure increase valve when a brake operation member is strongly operated. <P>SOLUTION: The hydraulic booster is provided with a control piston in which brake operation input is applied in an advancing direction and reaction force based on a liquid pressure of a servo liquid pressure generation chamber for generating the liquid pressure for operating a master piston is applied in a retreating direction; the pressure increase valve interposed between the servo liquid pressure generation chamber and the liquid pressure generation source so as to be opened at advancing of the control piston and closed at retreating of the control piston; and a pressure reduction valve interposed between a release chamber and the servo liquid pressure generation chamber so as to be closed at advancement of the control piston and opened at retreating of the control piston. In this case, the pressure increase valve 106 comprises first and second valve means 141, 142 successively opened according to increase of the brake operation input and a seal diameter of the second valve means 142 is set larger than a seal diameter of the first valve means 141. <P>COPYRIGHT: (C)2007,JPO&INPIT |
