Abstract:
La présente invention s'applique principalement à une valve pneumatique de limitation du niveau de pression d'un fluide pneumatique obtenue par une source de fluide pneumatique à basse pression (3) à un élément pneumatique (5) utilisant ledit fluide pneumatique caractérisée en ce que ladite valve comporte un carter (11) dans lequel est montée à coulissement étanche une jupe (21), ladite jupe divisant l'intérieur du carter (11) en une première chambre (17) et en une seconde chambre (19), ledit carter comportant un premier orifice (13) permettant l'alimentation par la source (3) de fluide pneumatique à basse pression de la première chambre (17), un second orifice (15) mettant en communication la première chambre (17) et l'élément (5) et un troisième orifice (23) permettant l'alimentation en fluide pneumatique à haute pression de la seconde chambre (19), la première chambre (17) comportant également des moyens élastiques (27) de rappel de la jupe (21) interposées entre la jupe (21) et le carter (11), ladite jupe (21) comportant des moyens obturateurs (33, 41) d 'au moins un orifice de communication (13, 15) entre la source (3) de vide et l'élément (5) pneumatique.
Abstract:
The invention relates to a vacuum brake booster (10) comprising a vacuum chamber (16), a working chamber (18) which is separated from said vacuum chamber by a moveable wall, and a control valve (20) comprising a housing (12) which is coupled to the moveable wall in a force-transmitting manner (14). Said control valve is able to control the supply of atmospheric pressure or vacuum to the working chamber (18) according to the displacement of an actuating piston (28), in order to obtain a pressure difference on the moveable wall (14). The inventive vacuum brake booster (10) comprises an emergency braking auxiliary system having a permanent magnet (38) and an armature (36) which interacts with the permanent magnet (38). Said armature is elastically pre-stressed against the actuating direction and is pulled by the permanent magnet (38) in the event of emergency braking in the system, in such a way that the control valve (20) is held open for the supply of atmospheric pressure to the working chamber (18). The vacuum brake booster (10) comprises a coupling device (90) for detachably coupling the armature (36) to the actuating piston (28).
Abstract:
The invention concerns a power-assist brake pneumatic servomotor for a motor vehicle comprising a one-way clutch device (56) comprising a coaxial bushing (58) sliding on a plunger (46), and a substantially annular key (60) enclosing the bushing (58) with play and capable, when an input force is applied at a predetermined speed on a control rod (38) integral with the plunger (46), of being driven by a mobile piston (22) in an axial position wherein it locks a feeler (52) stressing the piston (22) independently of the control rod (38). The invention is characterised in that the feeler (52) is axially secured to the bushing (58) and means are provided for axially indexing the position locking the bushing (58).
Abstract:
The invention concerns a power-assist brake pneumatic servomotor for a motor vehicle comprising a one-way clutch device (56) comprising a coaxial bushing (58) sliding on a plunger (46), and a substantially annular key (60) enclosing the bushing (58) with play and capable, when an input force is applied at a predetermined speed on a control rod (38) integral with the plunger (46), of being driven by a mobile piston (22) in an axial position wherein it locks a feeler (52) stressing the piston (22) independently of the control rod (38). The invention is characterised in that the feeler (52) is axially secured to the bushing (58) and means are provided for axially indexing the position locking the bushing (58).
Abstract:
In order to improve the braking force support in emergency braking operations, an armature (18) which co-operates with a permanent magnet (19) is provided in the control valve housing (7) of a vacuum-powered brake servo. Said armature is coupled to the actuating member (8) in the direction of actuation. The armature (18) is prestressed in an elastic manner against the direction of actuation and is held at a first distance from the permanent magnet (19) whilst the control valve (6) is in the initial position. In the course of an emergency braking operation, the armature (18) approaches the permanent magnet (19) and as soon as the distance between said armature and the permanent magnet falls short of a second predetermined distance which is less than the first distance, the armature is drawn by the permanent magnet against the elastic prestressing force acting upon said armature (18) into position against the permanent magnet (19), disconnecting the rigid coupling in the direction of actuation to the actuating member (8). In order to adjust the distance between the armature (18) and the permanent magnet (19) of the vacuum-powered brake servo (1) in its inactive state, the axial position of the permanent magnet (19) in relation to the control valve housing (7) and/or the distance between the armature (18) and the valve seat (10) can be set.
Abstract:
A negative pressure type booster, comprising a valve seat member (40), a spring (47) energizing the valve seat member (40), and a holding member (52) having an engaging part (52b) disposed on a power piston (22) movably only in radial direction and engaged with the valve seat member (40) and a tapered part (52a) in contact with a plunger (37), whereby, when the amount of movement of an input member (27) relative to the power piston (22) is larger than a specified value, the input member (27) is brought into contact with the tapered part (52a) and moves the holding member (52) in radial direction to disengage the holding member (52) from the valve seat member (40) in order to allow the valve seat member (40) to be moved rearwards.
Abstract:
The invention relates to a brake booster with a panic braking function, for motor vehicles. Said brake booster comprises a booster housing (1), the inside of which is divided into a first chamber (2) and a second chamber (3) by a moveable wall; and a control housing (8) wherein a control valve (5) is located, said control valve being used to control a pneumatic pressure differential which acts upon the moveable wall, and being activated by means of a control rod. The control valve has a first sealing seat (15), a second sealing seat (16) which is configured on a valve piston (6), and an elastic valve body (10) which interacts with the two sealing seats (15, 16). Means are also provided for generating a rapid increase in the booster power provided by the brake booster when the control valve is activated quickly. The invention is characterised in that the first sealing seat (15) is arranged in such a way that it can move in relation to the control housing (8), and in that means (26) are provided for fixing the sealing seat (15) when the relative displacement between the valve piston (6) and the control housing (8) exceeds a predetermined value, said means (26) then preventing the sealing seat (15) at least from moving in the direction of activation (30). The brake booster with auxiliary braking functions is easy to produce and ensures that the braking power can be regulated in the emergency braking position.
Abstract:
The invention concerns a pneumatic servomotor controlled by a plunger (9) housed in a bore (61) and bearing a mobile seat (102) designed to co-operate selectively with a closure member (111), said member being itself capable of selectively co-operating with a fixed seat (101). The invention is characterised in that the plunger (9) comprises a cylindrical body (91) and a ring (92) sliding between front (911) and rear (912) stops, a front section (921) of the ring (92) being engaged between the cylindrical body (91) and the bore (61), a rear section (922) of the ring (92) bearing the mobile seat (102), and the ring (92) being further capable of being temporarily maintained fixed in the bore, independently of the body (91) movement, by means of a flip switch (13) and an elastic lock ring (141), to enable prolonged actuating of the servomotor after sudden brake application.
Abstract:
The invention concerns a pneumatic servomotor controlled by a plunger (8) whereof a rear section (82) controls a check valve (91, 92, 93) and which is housed in a pneumatic piston (5) designed to apply a boosting force to force transmitting members (12, 14). The invention is characterised in that the plunger (8) comprises a front section (81) connected to the rear section by a spring (15), the front section (81) and the force transmitting members (12, 14) themselves comprising retaining means (16, 17) for securing the front section (81) to the piston (5) when the boosting force exceeds a predetermined threshold while the plunger is in maximum actuating position, and for enabling a prolonged actuation of the servomotor after the brake has been suddenly applied.
Abstract:
The invention relates to a power assisted brake for motor vehicles, comprising an assistance-device housing (1) whose inner space is divided by a movable wall (2) into a vacuum chamber (4) and a working chamber (3), as well as a control valve (12) which controls a pressure difference acting on the movable wall (2) and is positioned in a control casing (5) supporting the movable wall (2). The control valve (12) consists of at least two sealing seats (15, 16) which are arranged concentrically in relation to each other and a valve body (10) which in the control casing (5) delimits a pneumatic space (17) which can be subjected to the pneumatic pressure prevailing in the working chamber (3). The essence of the invention lies in the fact that the valve body (10) is provided with at least two sealing lips (50, 51) having different diameters which delimit the pneumatic space (17) in the control casing (5) and in that the active pneumatic surface of the space (17) influenced by the difference in diameter substantially coincides with the pneumatic surface delimited between the two sealing seats (15, 16).