Abstract: A pneumatic brake servo for motor vehicles having a servo housing, the interior of which is divided into at least one working chamber and at least one vacuum chamber by at least one axially movable wall which can be loaded with a pneumatic differential pressure, having a control valve which controls the differential pressure and is arranged in a control housing for connecting the working chamber to the vacuum chamber or to atmosphere. The movable wall includes a diaphragm plate and a rolling diaphragm, and the working chamber is sealed by a sealing ring which bears against the control housing and which is clamped in the radial direction in relation to a longitudinal axis of the brake servo. An actively loaded area of the movable wall is reduced by division of the working chamber into a prechamber and a main chamber to avoid stick/slip effects and reduce disruptive noises.

Abstract: A pneumatic brake servo for motor vehicles having a servo housing, the interior of which is divided into at least one working chamber and at least one vacuum chamber by at least one axially movable wall which can be loaded with a pneumatic differential pressure, having a control valve which controls the differential pressure and is arranged in a control housing for connecting the working chamber to the vacuum chamber or to atmosphere. The movable wall includes a diaphragm plate and a rolling diaphragm, and the working chamber is sealed by a sealing ring which bears against the control housing and which is clamped in the radial direction in relation to a longitudinal axis of the brake servo. An actively loaded area of the movable wall is reduced by division of the working chamber into a prechamber and a main chamber to avoid stick/slip effects and reduce disruptive noises.

Abstract: A vacuum brake power booster (1) has an electric travel sensor (3) for monitoring the position of a movable wall (4) furnishing the boosting power of the brake power booster. The travel sensor (3) is mounted by a sensor receptacle (2) which is made of plastic material and which is sealed off with respect to the booster housing (10) by means of a seal. In order to assure effective sealing by creating a constant degree of compression of the seal (7) despite different material thicknesses of the booster housing (10), angled tabs (12) are formed against which locking projections (11) are abutted.

Abstract: A boot (19) protecting the pedal-sided end (18) of the control valve housing (5) of a vacuum brake force booster is fixed by a spacer. The spacer is preferably configured as a dual-walled annular sleeve (20). It is axially secured in the same position as a ring sealing the control valve housing (5) against the booster housing (1). An axial extension (26) of sleeve (20) insures that the boot (19) is kept remote from the booster housing (1) and from the control valve housing (5), respectively, so that air can be taken in between boot (19) and control valve housing (5) for ventilating the working chamber (3). This design allows the air required for ventilation to travel very closely to the baffle wall, thereby minimizing noise in the passenger cabin of the automobile.

Abstract: A vacuum-operated brake power booster is provided having a movable wall which is sealed off relative to the vacuum housing and a control valve body which is slidable jointly with the movable wall. A hollow cylinder-shaped expanded plastic ring is arranged in the annular clearance between the neck portion of the pedal side housing shell and the collar of the diaphragm, which collar sealingly surrounds the control valve body. The expanded plastic ring effects the air flow during brake operation such that the air flow, enters the annular clearance through the duct extending in a radial direction within the control valve body and is suitably deflected and cushioned so that no noises arise at this point. In the same manner and simultaneously, vibrations, especially those of the neck portion of the housing shell of the vacuum housing, are suppressed, since the expanded plastic ring adheres to the inside wall of the housing shell.