Motor vehicle hydraulic brake system - has hydraulic power booster with integral pressure reservoir for emergency application

摘要

The hydraulic brake booster has a main housing with inlet for pressure medium from supply source and return pipe to reservoir. A foot operated device controls a valve providing connection between inlet and return pipe on one hand and the inlet and pressure chamber on the other one. A piston moving in the housing bore defines a chamber, into which it is resiliently engaged. The chamber is coupled to the inlet by a pressure relief valve on a preset pressure gradient between them. Part of the pressure medium supply is deflected from the inlet into the chamber via a valve responding to the pressure relief valve actuation, as well as to the failure of pressure medium supply to the inlet, in order to connect the emergency pressure medium reservoir to the chamber.