Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which at least one axial piston is slideably mounted, of the type in which the bore (14) comprises two seals, front (30, 34) and rear, interposed between the piston and the bore (14), the seals (30, 34) comprising three radially concentric lips accommodated in grooves (70, 72) in the bore (14), characterized in that front faces of the grooves (70, 72) are configured at least in part as a slope.

Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which at least one axial piston is slideably mounted, of the type in which the bore (14) comprises two seals, front (30, 34) and rear, interposed between the piston and the bore (14), the seals (30, 34) comprising three radially concentric lips accommodated in grooves (70, 72) in the bore (14), characterized in that the seals (30, 34) comprise central lips of reduced cross section.

Abstract: Master cylinder for a hydraulic braking circuit, particularly for a motor vehicle, comprising an annular seal (1) placed in a housing (6) of the body comprising an internal dynamic sealing lip (14) surrounding the piston, fitting into an annular groove (20) of the piston when this piston is in a rear rest position, an outer static sealing lip (10) pressing against a wall of the housing, and an additional static sealing lip (16) which presses against a wall of the housing of this seal and with the outer lip defines a small closed volume (V) of liquid.

Abstract: Master cylinder of a hydraulic braking circuit, particularly for a motor vehicle, comprising a piston (2) sliding axially in a body (4) comprising an annular lip seal (51) produced by molding, and comprising an internal, dynamic sealing lip (14) surrounding the piston and connected by a curved surface (36) to a planar rear face (30) comprising radial passages which are defined by blocks formed as projections on the rear face of the seal, these blocks being separated from the curved surface (36).

Abstract: The invention relates to a master cylinder (1) with reduced free travel (23). Current master cylinders have a free travel during the displacement of a piston (6) in a bore (5) of a master cylinder body (3). Such a free travel may be reduced with the aid of a frustoconical portion (24) in the piston, an orifice (14) for communication of hydraulic fluid being situated on said inclined wall, a gap (26) between the inclined wall and an inner wall (12) of the bore allowing a passage for hydraulic fluid capable of filling a pressure chamber (4). However, such inclined walls create a change in the slope of an outer wall (29) of the piston, this change being able to cause a separation of an inner lip (19) of a sealing cup (17). To prevent this separation, the invention provides that the inclined wall forms a convex rounded surface (32).

Abstract: Our problem relates to a master cylinder with a U-shaped seal. Our goal is to avoid defective bleeding of hydraulic braking systems. The defects arise out of the fact that the vacuum causes the lips of the seal (21) to stick together and to stick against the wall (41). To achieve this, reliefs (42) will be created on one wall (44) of one lip (28) facing the other lip (27) and on the edge face (50) of this same lip. These reliefs will prevent the lips from sticking tightly to one another and to the wall facing the edge face of the lips. This lack of sticking will prevent a vacuum from being created between the two lips and between the edge face of the lips and the wall (41). As a result, the seal will be able to return to a position in which bleeding can be performed effectively.

Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which is slideably mounted at least one axial piston, of the type in which the bore (14) comprises two seals, front and rear, interposed between the piston and the bore (14), characterized in that it comprises at least one wide groove (66, 68) which is formed in the bore (14) in front of a groove (70, 72) for retaining the front seal, which extends at least in part around the piston, and which communicates with said retaining groove (70, 72) and the hole in the piston, in order to allow resupplies to occur with a high flow rate.

Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which at least one axial piston is slideably mounted, of the type in which the bore (14) comprises two seals, front (30, 34) and rear, interposed between the piston and the bore (14), the seals (30, 34) comprising three radially concentric lips accommodated in grooves (70, 72) in the bore (14), characterized in that front faces of the grooves (70, 72) are configured at least in part as a slope.

Abstract: Brake master cylinder (10) for a motor vehicle, of the type which comprises a substantially axial body (12) inside a bore (14) of which at least one axial piston is slideably mounted, of the type in which the bore (14) comprises two seals, front (30, 34) and rear, interposed between the piston and the bore (14), the seals (30, 34) comprising three radially concentric lips accommodated in grooves (70, 72) in the bore (14), characterized in that the seals (30, 34) comprise central lips of reduced cross section.

Abstract: A pneumatic brake booster (10) having a moving piston (22) for urging an actuating rod (34) of a master cylinder (28) in response to actuation of a plunger (56). The plunger has a front end that passes through the piston (22) that forms a first feeler (62) that penetrates a reaction disc (44) located between the piston (22) and the actuating rod (34) to transmit to the plunger (56) a reaction force of the master cylinder (28) and a second feeler (68) that is pushed by the plunger (56) when the control rod (46) is actuated at a rate higher than a determined rate and immobilized by a one-way engagement device (70) in an axial position that varies with respect to the piston (22) and then is driven by the piston to push the second feeler (68) into the disc (44) so that the first feeler (52) applies a braking force more rapidly.

Abstract: A braking device for a motor vehicle, including a master cylinder (2) with a primary piston (3) subjected to an actuating force of an input force exerted by a manual operating member (4) and a boost force exerted by a booster (6) coupled to the manual operating member (4) and an emergency assist valve (VA). Valve (VA) comprises: a reaction piston (19) sliding in a bore (20) of the primary piston (3) and urged toward a position of rest by by an elastic return member (22); a rapid piston (32) having a cross section smaller than the reaction piston (19) and sliding in a sealed manner in a bore (31) of a bushing (30) in bore (200; and a ratio control (27) actuated by a plunger distributor (10) driven by the manual operating member (4). The elastic return member (22) is arranged outside of the primary piston (3) and a transmission element (T) is provided to transmit a return force of the elastic return member (22) to the reaction piston (19).

Abstract: A pneumatic brake booster (10) of the type comprising a moving piston (22) urging an actuating rod (34) of a master cylinder (28) in response to actuation of a plunger (56) of which a front end, passing through the piston (22) and forming a first feeler (62) can, when the plunger (56) is in the extreme position, penetrate a reaction disc (44) inserted between the piston (22) and the actuating rod (34) to transmit to the plunger (56) the reaction force of the master cylinder (28), characterized in that it comprises a second feeler (68) which can, when the control rod (46) is actuated at a rate higher than a determined rate, be pushed by the plunger (56) and immobilized by a one-way engagement device (70) in an axial position that varies with respect to the piston (22), then be driven by the piston to push the second feeler (68) into the disc (44) so that the first feeler (52) applies a braking force more rapidly.

Abstract: A braking device for a motor vehicle, including a master cylinder (2) with a primary piston (3) subjected to an actuating force of an input force exerted by a manual operating member (4) and a boost force exerted by a booster (6) coupled to the manual operating member (4) and an emergency assist valve (VA). Valve (VA) comprises: a reaction piston (19) sliding in a bore (20) of the primary piston (3) and urged toward a position of rest by by an elastic return member (22); a rapid piston (32) having a cross section smaller than the reaction piston (19) and sliding in a sealed manner in a bore (31) of a bushing (30) in bore (200; and a ratio control (27) actuated by a plunger distributor (10) driven by the manual operating member (4). The elastic return member (22) is arranged outside of the primary piston (3) and a transmission element (T) is provided to transmit a return force of the elastic return member (22) to the reaction piston (19).