摘要 |
A servo booster including a piston plate for receiving a differential pressure produced across two chambers which are defined in a shell casing, a cylindrical valve body having a valve mechanism therein for controlling the pressure across the two chambers, an aperture and a head portion formed respectively at the center portion of the piston plate and at an end portion of the valve body and being engageable with each other at a predetermined angular position, and the relative movement of the valve body and the piston plate in the direction of the axis of the servo booster being prevented by rotating the head portion through a predetermined angle in the aperture, wherein the improvement comprises a rotation preventing member rigidly mounted on the piston plate and having one portion thereof in fitting engagement with the valve body to prevent the relative rotation of the valve body and the piston plate. |