| 摘要 |
<p>The booster comprises a housing which defines a pressure chamber 26 and supports a control valve 32 and a piston 34. The control valve co- operates with an actuator 36, 38 to move relative to the housing so as to communicate pressurized fluid from inlet 50 to the pressure chamber and the piston is movable in response to the pressurized fluid within the pressure chamber to effect braking. In order to limit the level of pressure of pressurized fluid communicated to the pressure chamber a ring 56 is disposed within the housing in co- operation with the control valve. The ring co-operates with the control valve to define a differential area which is exposed to pressurized fluid to generate a force opposing movement of the control valve so that communication of pressurized fluid to the pressure chamber is limited. <IMAGE></p> |
