Pneumatic braking servo for automobile braking circuit

摘要

The braking servo has a housing (1) divided internally by a movable wall (2) into a reduced pressure chamber (4) and a working chamber (3), with a control valve (12) for the pneumatic pressure difference acting on the movable wall. The control valve has a valve element (10) cooperating with a pair of valve seats (15,16) and is operated via an operating rod (7) and an electromagnet (20) associated with a third valve seat (24). The valve element has bores (19) lying radially outside the third valve seat, for pneumatic pressure equalisation.