Pneumatic braking servo for automobile has control valve with 3 concentric valve seats one of which is displaced to allow braking modulation during servo-assisted braking

摘要

The pneumatic braking servo has a housing (1) divided internally by a movable wall (2) provided with a control housing (7) with a control valve (6) which is operated via an operating rod (5) and a valve piston (10) and via an electromagnet (24). The control valve has 3 concentric valve seats (8,9,23) provided by the control housing, the valve piston and a sleeve cooperating with the electromagnet, the valve seat provided by the valve piston displaced relative to that provided by the sleeve, via the operating rod.