Abstract: A pneumatic brake booster for a motor vehicle, of the type in which the movements of a control rod (38) are able to determine the openings and closings of at least one axial intake valve (52) which is inserted between a pressure source subjected to the pressure (Pa) higher than the first pressure (P1) and a rear chamber (18) of the booster, and of at least one axial equalizing valve (50) which is inserted between a front chamber (16) and the rear chamber (18), to actuate a moving partition (14) inserted between the front chamber (16) and the rear chamber (18), characterized in that it comprises a tubular element (76) of which axially offset transverse faces (78, 80) comprise first elements (82, 84) for sealing the axial intake and equalizing valves (50, 52) and that the control rod (38) is able to operate via two concentric springs (40, 122) having different stiffnesses.

Abstract: A pneumatic brake booster for a motor vehicle wherein movements of a control rod (38) determine the openings and closings of at least one axial intake valve (52) and at least one equalizing valve (50). The intake valve (52) being inserted between a pressure source subjected to the pressure (Pa) higher than the first pressure (P1) and a rear chamber (18) of the booster, and the equalizing valve (50) being inserted between a front chamber (16) and the rear chamber (18) to actuate a moving partition (14) located between the front chamber (16) and the rear chamber (18). A tubular element (76) of that is axially offset transverse faces (78, 80) comprised of first elements (82, 84) for sealing the axial intake and equalizing valves (50, 52).

Abstract: The invention relates to a pneumatic servomotor for an assisted braking, comprising a rigid casing (1) in which a moving airtight partition wall (2) defines a front chamber (3) and a rear chamber (4), a pneumatic piston (5) travelling with the moving partition wall (2), a plunger (8), housed within the piston (5) and driven by a control rod (7) and controlling the state of a three-way valve (9), force-transmitting means (10, 13, 17, 18, 31), adapted for receiving and transmitting at least one assistance force (Fa), exerted by a front face (51) of the piston (5) when the valve (9) puts the rear chamber (4) under a second pressure (Pa), the plunger (8) including a front section (81) comprising retaining means (18, 31) intended to tie down the front section (81) of the plunger (8) to the pneumatic piston (5).

Abstract: Braking device comprising a master cylinder (2), a primary piston (3), a manual control member (4), a booster (6) coupled to the manual control member (4) and an emergency assist valve (VA) comprising a reaction piston (17) through which there passes a ratio control (T) having a head (26a) situated in a chamber (35) lying between the reaction piston (17) and a bushing (36) located further forward in a bore (18) in the primary piston, this bushing (36) having a bore (37) in which there can slide a rapid piston (38), the rear end (45) of which forms, with the head (26a) of the ratio control, a valve (C) capable of closing the inlet to a passage (39) in the rapid piston against the action of a spring (41). The device comprises a means (26, 27, 30) for preventing a sharp retreat of the reaction piston (17) when the manual control member (4) is released after slow braking.

Abstract: A boosted braking device for a motor vehicle having a master cylinder (200) and a pneumatic booster (100) operated by applying an input force to an operating rod (26). The booster (100) has a rigid casing (10) which is divided by a partition (16) into at least first (12) and second (14) leaktight chambers. The partition (16) is acted upon via a difference in pressure between the first (12) and second (14) chambers on the opening of a three-way valve (24) to allow pressurized fluid to be communicated to the second chamber (14). A main hydraulic piston (30) which is located in the master cylinder (200) has a hollow cylinder (32) which is in communication with an interior volume (V) of the master cylinder (200). A secondary hydraulic piston (34) slides in a leaktight fashion inside of the hollow cylinder (32).