| 摘要 |
<p>The invention relates to a servomotor for assisting the operation of a power brake system. The servomotor includes in a housing a power-assisting part and a part forming a hydraulic master-cylinder. The power-assisting part is adapted in use to be connected to an external power source such as a vacuum source. A valve assembly operated by an operator-operated intake member controls the generation of a pressure differential across a driving piston by allowing air to replace the vacuum on one side of the piston. The master-cylinder part includes an assembly having two coaxial pistons. The first piston is attached to the driving piston of the power assist part whereas the second piston is actuated by the intake member. Both coaxial pistons project into a chamber which is divided by a sealing ring. The central piston is adapted to pass through the sealing ring in response to an input force from the input member to further pressurize the fluid in the outlet portion of the chamber.</p> |
