Abstract:
The invention relates to a vacuum brake booster (10) comprising a vacuum chamber (16), a moveable wall (14), a working chamber (18) and a control valve. The aim of the invention is to provide an emergency brake aid (brake assistant function). The rear side of the valve member (38) is permanently exposed to the pressure prevailing in the working chamber (18), whereby said rear side faces the input member (24). At least one part of the front side pertaining to said valve member is exposed to the pressure prevailing in the vacuum chamber (16) when the displacement of the displaceable valve member (38) in the direction of actuation with respect to the control valve housing (22) is exceeded, whereby said front side is opposite the rear side and said displacement is predetermined. The pressure difference which then prevails on the displaceable valve member (38) holds said valve member in the obtained position until pressure between the front side and the rear side of the displaceable valve member (38) is compensated. A component that is coupled to the input member (24) in the opposite direction of actuation of the brake booster (10) operates for switching off the brake assistant function.
Abstract:
The invention relates to a tandem brake booster for automobiles, comprising two booster units, each consisting of a vacuum chamber (12, 22) and a working chamber (13, 23), located in a housing where they are divided by a dividing wall (2). In each booster unit, the pressure difference between the pressure in the vacuum chamber and the pressure in the corresponding working chamber, which can be influenced by a switching device (16, 7), acts on a piston separating the vacuum chamber and the working chamber, and the forces acting on the pistons, which are proportional to the pressure difference, are combined with the forces applied by the driver of the vehicle to a corresponding brake pedal (3) through mechanical intermediate mechanisms, by means of respective transmitting elements. The inventive configuration improves the metering of an automobile brake system since the additional brake forces provided by the tandem brake booster are, to a particularly great extent, only provided if necessary, i.e., in emergency braking situations.
Abstract:
A pneumatic brake servo using two air pressure sources and including a rigid shell (3) divided into at least two chambers (3a, 3b) by a movable sealing wall (4) capable of being biased by a pressure differential caused by the operation of a valve (7) that includes a tubular sealing member (70) defining, together with an inner piston surface (510), a compensation space (74) in continuous communication with the second chamber (3b). The sealing member (70) of the valve (7) has a continuous sealing surface opposite the two seats (71, 72), and the compensation space (74) communicates with the second chamber (3b) via an axial bore in a thicker portion (S) of the cylindrical wall (51) of the pneumatic piston (5).
Abstract:
The invention concerns a valve assembly (10) for controlling a pneumatic brake booster, said valve assembly comprising a valve housing (16) with a first and a second valve seat (18, 20) and a valve body (26) which can be applied against both valve seats (18, 20). In one position of an actuating member (24) the valve body (26) is raised only off the first valve seat (18) whilst, in another position of the actuating member (24), it is raised off the second valve seat (20). An annular third valve seat (64) is disposed radially outside the valve housing (16), and a control sleeve (60) surrounding the valve housing can, as an additional valve body, be axially displaced by the actuating member (24) with respect to the valve housing (16). When the actuating member (24) performs a movement which goes beyond the movement necessary for raising the valve body (26) off the second valve seat (20), a venting duct is opened which is formed by a ring (70) which surrounds the valve housing (16) at least partially, is disposed on the valve housing (16) at an axial spacing from the control sleeve (60), and has a cavity (74) which has an inlet (78), connected to an air feed line (76), and an outlet (80). A valve assembly (10) of this type can be produced efficiently and more economically.
Abstract:
Pneumatic brake servo comprising within a shell-shaped casing (10), a piston (22) delimiting, in conjunction with a rolling diaphragm (18), a front chamber (26) permanently connected to a low pressure source and a rear chamber (28) selectively connected to the front chamber (26) or to a high pressure source by at least one valve means (62, 58a, 70a). Said valve means is actuated by a control rod (38) disposed in the brake booster's axis of symmetry (X, X') and is capable of engaging, through the front face (36) of a plunger, the first surface of a reaction disk (37) integral with the second face of a thrust rod (35). Said valve means (62, 58a, 70a) is controlled by a transfer key (44) integral with the plunger (36) and includes a valve element (62) co-operating with a first valve seat (58a) formed on the piston (22) and a second valve seat (70a) formed on a valve piston (98) integral with the transfer key (44). According to the invention, the valve means (62, 58a, 70a) is entirely disposed in an enclosure (54) formed on the piston (22).
Abstract:
Pneumatic control device for a vacuum brake servo using, within a piston (5), a tubular sealing member (21) co-operating with a stationary seat (18) and with a moveable seat (19). The tubular sealing member (21) defines, within the piston (5), a chamber (22) with an opening (23) communicating with a passage (20) located between the two seats. As a result, a substantial elastic force acting on the sealing member (21) is not required.
Abstract:
A pneumatic brake servo comprises a casing (10) enclosing a piston (20) composed of a boss (34) and skirt (32). The casing (10) defines a front chamber (16) permanently connected to a vacuum source and a rear chamber (18) selectively connected to the front chamber (16) or to the atmosphere by means of a valve member (60, 62) actuated by a control rod (54) capable of coming to rest, through the front face of a plunger (44), on the rear surface of a reaction disc (48) integral with a thrust rod (52). A return spring (84) for the control rod (54) is disposed between the piston (34) and the plunger (44), the valve member (60, 62) including a shutter co-operating with a first circular valve seat (44a) on the piston (20), the shutter (60, 62) including a flexible membrane (60) of a generally truncated cone shape, sealingly fitted by its outer peripheral edge to the piston (20). According to the invention, the flexible membrane (60) is sealingly connected by its inner peripheral edge to a rigid tubular part (62) sealingly sliding in a rear tubular part (22) of the piston (20).
Abstract:
A pneumatic brake servo comprising a housing (10) containing a piston which consists of a hub (20) and a skirt (14), and defining, by means of a roll-up membrane (12), a forward chamber (16) which constantly communicates with a vacuum source, and a rear chamber (18) which is selectively communicable with the forward chamber (16) when a first valve passage (56, 58) is open, or with the atmosphere when a second valve passage (76, 78) is open, said valve passages (56, 58; 76, 78) being defined by first valve members (58, 78) cooperating with second valve members (56, 76), and actuated by a control rod (35) which is engageable, via a plunger (32), with one side of a reaction disc (42) that is rigidly fixed to a push rod (44). Said first valve members (58, 78) are provided on the piston hub (20).
Abstract:
Die Erfindung betrifft einen Drucksensor (1) für einen Bremskraftverstärker, mit einem Gehäuse (3), welches ein Drucksensorelement (9.1) aufnimmt und einen ersten Fluidanschluss (7) aufweist, über welchen der Drucksensor (1) mit dem Bremskraftverstärker verbindbar ist. Hierbei weist das Gehäuse (3) einen zweiten Fluidanschluss (10) mit einer Aufnahmeöffnung (10.1) auf, welche ein Durchflussventil (12) und einen Anschlussstutzen (11) für eine Vakuumpumpe zumindest teilweise aufnimmt, wobei das Durchflussventil (12) einen Fluidfluss in Richtung Vakuumpumpe freigibt und einen Fluidfluss in entgegengesetzter Richtung sperrt, wobei das Durchflussventil (12) als Membraneinsatz (13) ausgeführt und in die Aufnahmeöffnung (10.1) eingeführt ist.
Abstract:
Die vorliegende Erfindung betrifft einen Unterdruckbremskraftverstärker (10), mit: wenigstens einer beweglichen Wand (18), die eine Arbeitskammer (14) und eine Unterdruckkammer (16) in dem Unterdruckbremskraftverstärker (10) voneinander trennt, und einer Steuerventileinheit (20), die mit der wenigstens einen beweglichen Wand (18) gekoppelt ist, wobei die Steuerventileinheit (20) eine Führungshülse (34) und einen verlagerbar in der Steuerventileinheit (20) geführten Betätigungskolben (24) umfasst, der über ein insbesondere mit einem Bremspedal (28) koppelbares Krafteingangsglied (26) betätigbar ist, wobei der Betätigungskolben (24) wenigstens einen ersten Ventilsitz (52) aufweist, der im geöffneten Zustand zur Verbindung der Arbeitskammer (14) mit der Umgebungsatmosphäre dient, wobei der Betätigungskolben (24) einen ersten Strömungssteuerungsabschnitt (60), der in Richtung der Führungshülse (34) vorsteht, und die Führungshülse (34) einen zweiten Strömungssteuerungsabschnitt (62) aufweist, der in Richtung des Betätigungskolbens (24) vorsteht, wobei der erste Strömungssteuerungsabschnitt (60) und der zweite Strömungssteuerungsabschnitt (62) zur Steuerung des zu dem ersten Ventilsitz (52) strömenden Luftstroms zusammenwirken.