Pneumatic servomotor with controlled self-assistance force for use in vacuum assisted brake servomechanisms for motor vehicles

摘要

The brake servo has a plunger (8) with its rear section controlling a check valve (91,92,93) which houses a pneumatic piston (5). The plunger has a front section (81) connected to the rear section by a spring (15). When the assistance force exceeds a threshold, a lip (16,17) inside the pneumatic piston (5) engages a lip on the front section (81), and delays return of the plunger.