Pneumatischer Bremskraftverstärker

摘要

The invention concerns a braking force booster for motor vehicles, the control valve (12) of which can, independently of an actuating rod (7) moving a valve piston (9), be actuated by an electromagnet (20) which in turn actuates a third sealing seat (24), the movement of which against the direction of actuation of the brake booster makes it possible to aerate the working chamber (3). In order to eliminate all force components of pneumatic components during external actuation, according to the invention there is a permanent pneumatic connection between a pneumatic chamber (17) bounded by the valve body (10) in the control housing (5) and the underpressure chamber (4), and both a second sealing seat (16) formed on the valve piston (9) and aerating the working chamber (3) and the third sealing seat (24) and the component (sealing lip 13) of the valve body (10) bounding its pneumatic chamber (17) in the control housing (5) are virtually of the same diameter.