Vacuum operated vehicle braking force amplifier

摘要

A vacuum-operated brake power booster with a booster piston (19), sealed relative to the booster housing (7), and a piston rod (14), coupled with a braking pedal, for the actuation of a double valve (11, 9 and/or 11, 12), through the intermediary of which a working chamber (20) of the brake power booster is connectible either to a vacuum or to a higher pressure, wherein a first valve (11,12) is formed by a valve seat (12) at the control housing (2) associated with the booster piston (19) and a poppet valve (1) pre-loaded in the direction of the valve seat (11), and a second valve (9,11) is formed by the same poppet valve (1) and a valve piston (16,9) connected to the piston rod (14), the control housing (2) being provided with an aperture (40) protruding through which is a transverse member (41) which confines the axial position of the valve piston (16) relative to the control housing (2) and which radially protrudes from the aperture (40) and abuts on a stationary stop in the inoperative position characterised in that a slide-guide ring (24) embracing the control housing (2) and held by the booster housing (7) includes on its side directed towards the booster piston (19) a bead (8) made of a rubber-elastic material against which bead the transverse member (41) bears in the inoperative position.