Vacuum brake booster with mechanical emergency braking aid

Abstract

A vacuum brake booster () is described, comprising a vacuum chamber () and a working chamber () separated from each other by a movable wall (), as well as a control valve () which comprises a housing () coupled workingly to the movable wall and which is capable of controlling the supply of atmospheric pressure or above-atmospheric pressure to the working chamber () in dependence upon the displacement of an input element () of the brake booster () to achieve a pressure difference at the movable wall (). The vacuum brake booster () has a sensing disk (), which is disposed in an axially displaceable manner inside the control valve housing (), as well as a coupling device (), which introduces forces acting counter to the actuating direction upon the sensing disk () in a coupled position into the control valve housing () and in an uncoupled position via an actuating piston () into the input element (). The coupling device () comprises a coupling element () for introducing forces acting counter to actuating direction into the control valve housing () as well as an axially displaceable actuating element (). The coupling device () further comprises a detent element (), which is movable in radial direction and disposed radially outside of the coupling element (), and the coupling element (), radially at the outside, has a stop (B) for the detent element (), wherein in the coupled position the forces acting counter to actuating direction are introduced by the coupling element () via the stop (B) and the detent element () into the control valve housing ().