| 摘要 |
An auxiliary generating cylinder has a pedal-operated piston by means of which pressure medium is supplied to a slave cylinder actuating a brake member and/or a clutch release yoke. Between the auxiliary generating cylinder and the slave cylinder is connected a pneumatic vacuum boosting device (110). The latter comprises an axially displaceable control piston (3) arranged coaxially in relation to a working piston (4), as well as a pneumatic vacuum power booster comprising in a booster housing (21) a vacuum chamber (23) of constant pressure, a working chamber (24) of variable pressure and a movable wall (22) cooperating with the working piston. A control valve device, which is controllable by the control piston (3) includes a control valve housing (6), a first (28) and a second valve seat (29) as well as a poppet valve (30) coacting with both seats. Movement of the movable wall, caused by a pressure difference which acts on opposite sides thereof is transmitted onto the working piston to which is coupled directly. The control valve housing (6) is arranged stationarily in the booster housing (21) separately from the movable wall (22). The control piston (3) is of tube-shaped configuration and guided on the working piston (4) in sealed relationship thereto. The supply of the hydraulic pressure medium required for driving the actuating device takes place along its longitudinal axis. <IMAGE> |
