Vacuum servo unit for vehicle braking systems has front section of input rod engaging with rear section inside piston so that it is movable relative to rear section.

摘要

A vacuum servo unit for vehicle braking systems has: - a housing (14) with at least one pressure chamber; - a movable wall provided in the housing in a position to move axially forwards in the housing and to withdraw, the wall dividing the pressure chamber into a front and a rear chamber; - a force piston (22) coupled to the movable wall; - an input element (28) fitted into the force piston and movable forwards and backwards along the axial direction of the housing; and - an input rod (27) with front and rear sections (271,272), being coupled to the input and brake-operating elements respectively. The front section is found in engagement with the rear section inside the piston in such a way that the front section is movable relative to the rear section. The input rod is movable along the axial direction of the housing together with the brake operating element. There is also a valve mechanism (34) and an output element.