Abstract: A sensor assembly for use with a master cylinder is described. The master cylinder comprises an input-side activation element to which a signal transmitter element is coupled. The sensor module comprises a travel sensor for sensing travel carried out by the activation element, and a position sensor for sensing when a predefined position of the activation element is reached.

Abstract: Brake system comprising a thrust rod (130) driven by the servobrake (200) and actuating the piston (110) of the master cylinder (100), the servobrake (200) being linked by a hydraulic actuator (270) to the control rod (230) of the brake pedal (PF). The servobrake (200) comprises an actuator piston (220) controlled by an electric motor (265) via a rack drive (260). A simulator chamber (250) delimited by the hydraulic actuator (270) is subdivided by an intermediate piston (240) into a rear volume (V1) and a front volume (V2), respectively delimited by the intermediate piston (240). A duct (L1) links the rear volume (V1) to a duct (L2) linked to the front volume (V2) by a first solenoid valve (EV1) and the duct (L2) to the tank (115) by a second solenoid valve (EV2). The piston (240) is linked to the rod (130) bearing an abutment (132) to be thrust by the actuator piston (220).

Abstract: A vacuum assist pump system includes a vacuum assist pump for assisting to a brake system by vacuum, wherein it includes a suction compensation pump connected with the vacuum assist pump. Advantageously, a vacuum compensation reservoir is arranged between the vacuum assist pump and the suction compensation pump. The vacuum compensation reservoir comprises a vacuity sensor for its internal vacuity and two interfaces. One of the two interfaces communicates to the suction compensation pump, the other communicates to the vacuum assist pump.

Abstract: A braking system includes an emulator cylinder, an emulator actuator piston within the emulator cylinder, an emulator actuator chamber within the emulator cylinder defined in part by the emulator actuator piston, a pedal feel simulator including an input port in fluid communication with the emulator actuator chamber and an output port, a selector piston movable within the emulator cylinder between a first position and a second position, and a poppet valve operably connected to the emulator actuator piston, the poppet valve movable by the emulator actuator piston between a deactivated position and an actuated position and configured such that (i) when the selector piston is in the first position and the poppet valve is in the actuated position, the poppet valve is closed and the emulator actuator chamber is not in fluid communication with the reservoir through the poppet valve, and (ii) when the selector piston is in the second position and the poppet valve is in the actuated position, the poppet valve is open

Abstract: In a brake device, when a piston (38A, 38B) of a slave cylinder (23) seizes at an advanced position, an out-valve (60, 61) is opened to discharge brake fluid in a wheel cylinder (16, 17; 20, 21) to a reservoir (62). Then, an in-valve (54, 56) and the out-valve (60, 61) are both closed, and a pump (64) is activated. This allows the brake fluid in the reservoir (62) to be supplied to a fluid pressure chamber (39A, 39B) of the slave cylinder (23), enabling a piston (38A, 38B) of the slave cylinder (23), which has seized at the advanced position, to be pushed back to a retreated position. When the seizure of the piston (38A, 38B) is eliminated in this way, the brake fluid pressure generated in the master cylinder (11) can be supplied to the wheel cylinder (16, 17; 20, 21) via the fluid pressure chamber (39A, 39B) of the slave cylinder (23). Accordingly, it is proposed a method of eliminating seizure of a slave cylinder of a brake device capable of the backup of a failure in the slave cylinder (23).

Abstract: In a brake system, when setting a control origin position for a resolver for detecting a moved position of a booster piston, communication between a master cylinder and wheel cylinders is interrupted by cut valves. Thereafter, the booster piston is moved forward by an electric actuator in a direction in which a hydraulic pressure is generated so that a position detected by the resolver upon detection of generation of the hydraulic pressure by a hydraulic pressure sensor (position at a time of generation of hydraulic pressure) is obtained. A position obtained by moving backward the position at the time of generation of hydraulic pressure by a predetermined amount is set as the control origin position.

Abstract: An annular sealing member 95 for establishing sealing between a boosted hydraulic pressure application chamber 22 and an input-side annular chamber 93 formed between a casing and a backup piston 64A and connected to a hydraulic pressure source is disposed between the casing and the backup piston 64A, and communication passage 216 for establishing communication between the input-side annular chamber 93 and the boosted hydraulic pressure application chamber 22 as the backup piston 64A moves forward by a predetermined stroke or more is provided in one of the backup piston 64A and the casing.

Abstract: A normally closed secondary solenoid opening/closing valve 36 is provided along a secondary branched fluid pipe 35 establishing a communication between an accumulator 11 and a reservoir 8 through a fluid pressure input side to a fluid pressure output side of a regulator valve 3, and in the event that a fluid pressure supplied to the regulator valve 3 decreases down to or lower than a predetermined range due to something abnormal occurring in the accumulator 11, the state of the secondary solenoid opening/closing valve 36 is changed over from a closed state to an opened state, whereby a residual pressure in the accumulator 11 and a residual pressure in the output fluid pressure chamber 15 can be released through the reservoir 8 which is in communication therewith through an output fluid pipe 31 and the secondary branched fluid pipe 35 along which the secondary opening/closing valve 36 is provided.

Abstract: A master cylinder includes primary and secondary pistons both slidably mounted in the cylinder bore of a cylinder. A stopper plate is disposed in the cylinder bore behind the secondary piston. A groove having a larger diameter than the piston sliding surfaces is formed in the inner wall of the cylinder bore at its axially intermediate portion. The stopper plate includes a pair of diametrically opposed flanges having an outer diameter larger than the diameter of the piston sliding surfaces and smaller than the diameter of the groove. The flanges are received in the groove and engageable with a shoulder formed at the rear end of the groove, thereby preventing excessive backward movement of the secondary piston. The stopper plate has a dimension perpendicular to the direction in which the flanges extend and smaller than the diameter of the piston sliding surfaces. Thus, the stopper plate can be inserted into the cylinder bore with one of the flanges located ahead of the other.

Abstract: A pneumatic brake booster with short actuating travel, comprising a skirt and a pneumatic piston that are rigidly connected and slideably mounted in a sealed casing to delimit a low-pressure chamber and a variable-pressure chamber and a three-way valve arrangement that is controlled by a control rod connected at a first end to a brake pedal. The three-way valve arrangement having first and second valve seats and a valve that is applied to at least one of the first and second valve seats by a valve spring. The second valve seat being borne by a first longitudinal end of a plunger distributor while the first valve seat is borne by a first longitudinal end of a bushing slideably mounted in a sealed manner in the pneumatic piston over a defined first travel and beyond the defined travel the bushing is secured axially to the pneumatic piston.

Abstract: A brake hydraulic pressure generator is proposed in which the brake stroke fluctuate less when the amount of brake fluid consumed in the wheel brakes fluctuates. Even when the brake pedal force is increased after the brake assisting force has reached its maximum, the reaction force to the pedal force as well as the master cylinder pressure increases corresponding to the increased pedal force. The brake hydraulic pressure generator has a control valve including a spool and a cylinder and adapted to control the hydraulic pressure in a dynamic pressure chamber to a value corresponding to the stroke of an input shaft. It further includes a pressure sensor, a solenoid valve and a fluid chamber.

Abstract: A hydraulic brake apparatus is provided with a master cylinder, an assisting device for assisting the master piston to be advanced in response to operation of a brake pedal, and an auxiliary piston having a large diameter portion and a small diameter portion to define first and second pressure transmitting chambers, with the large diameter portion connected to the assisting device. A first valve member is provided for controlling the communication between the first and second pressure transmitting chambers, and a second valve member is provided for controlling a flow of the brake fluid from the first chamber to the second chamber. A valve opening mechanism is provided for opening the first valve member, and mechanically connecting the second valve member with the first valve member, to open the second valve member when the auxiliary piston is retracted from its advanced state to its initial position.

Abstract: A fuse device for a pneumatic brake booster, characterized by a hollow cylindrical first part (21) with a first end (25) having an inside diameter (d1) and a bowl-shaped second part (24) with a circular bottom equipped on its central external part with a roughly cylindrical stud (29) of an outside diameter (d2) slightly greater, within the tolerances, than the inside diameter (d1) of the end of the hollow cylindrical first part (21). The outside diameter (d2), allowing the hollow cylindrical first part (21) to be secured to the bowl-shaped second part (24) by forcibly inserting the stud (29) into hollow end (25) of smaller diameter (d1). The bowl-shaped second part (24) having a circular external groove (30) whose purpose is to weaken the connection between the stud (29) and the bottom (26) of the bowl-shaped second part (24) when a pair of forces is applied to the fuse device to allow the hollow cylindrical first part to detach from the bowl-shaped second part.

Abstract: An improved brake hydraulic pressure generating device is provided in which the hydraulic pressure supplied from a hydraulic pressure source is adjusted to a value corresponding to the brake operating force by means of a pressure adjusting valve which is activated according to displacement of an input piston or a simulator piston, and while the device is normal, a master cylinder is activated by the output hydraulic pressure. If the hydraulic pressure source or a hydraulic line connecting thereto fails, a sufficient braking force is ensured with a short stroke. There are provided a shutoff valve which shuts off communication between the simulator chamber and the atmospheric reservoir when the stroke of the input piston has exceeded a predetermined value, and a check valve which permits the flow of fluid from the atmospheric reservoir to the simulator chamber. This suppresses an unavailable stroke of the simulator piston without impairing the return of the simulator piston.

Abstract: A pressure-responsive type pressure holding valve is proposed which serves to hold the hydraulic pressure in a circuit connected to a spool valve. A piston valve biased by a spring is mounted in a housing formed with a valve chamber, a small-diameter bore and a large-diameter bore. The outer periphery of the small-diameter portion of the piston valve is sealed by a seal member. A first port opened and closed by a valve head at the tip of the piston valve is connected to a circuit that needs pressure holding, a second port to a circuit in which minute leak can occur, and a third port to a source of hydraulic pressure for opening the valve.

Abstract: The object of the present invention is to provide a brake fluid pressure generating apparatus which has a master cylinder with supplemental pressure room which operates the master cylinder independently of a depression of a brake pedal without structure complication. To perform this object, a master cylinder piston slides over seal cups which are arranged on a master cylinder side.

Abstract: A vehicle braking pressure source device including (a) a master cylinder having a pressurizing piston cooperating with a cylinder housing to define a pressurizing chamber and a back-pressure chamber on front and rear sides of the piston, and an input rod which slidably extending through a rear end wall of the cylinder housing such that the piston is advanced by a brake operating force of a brake operating member transmitted thereto through the input rod, to pressurize a working fluid in the pressurizing chamber, (b) a communication passage for communication between the pressurizing and back-pressure chambers, (c) a control valve device disposed in the communication passage for controlling the communication between the pressurizing and back-pressure chambers through the communication passage, and (d) a control valve control device for controlling the control valve device, on the basis of at least one of an operating state of the brake operating member, a running state of the vehicle and a state of a road surfa

Abstract: The brake force booster 1 with panic brake function includes a control valve, which is arranged in a control housing and operable by way of an input member, for controlling the boosting pressure in a working chamber, the said control valve including an atmosphere sealing seat on a valve piston and a vacuum sealing seat which is arranged on a sliding sleeve that is axially slidably mounted in the control housing. In the event of a panic braking, a quick depression of the brake pedal causes advance movement of the valve piston connected to the input member in relation to the control housing and the sliding sleeve, whereby opening of the atmosphere sealing seat is initiated and a clutch device is actuated which leads to supporting the sliding sleeve in the brake actuation direction on the elastically deformable reaction member, to which latter both the mechanically generated brake force and the pneumatic boosting force is applied. The clutch device is released by withdrawal of the input member.

Abstract: An air valve assembly is provided for a power piston in a vacuum brake booster including an input element with a hollow axial extension. The hollow axial extension includes a retaining portion. An output element is provided that includes an input extension slidably positioned within the hollow axial extension. The input extension includes an outer groove formed thereon and a ring member is disposed in the outer groove, the ring positioned adjacent the retaining portion to prevent separation of the input element and outer element.

Abstract: A hydraulic brake device for a vehicle includes a master cylinder having a master piston and an auxiliary piston for assisting the actuation of the master piston. The vehicle hydraulic brake device also includes a first valve mechanism for hydraulically closing a first pressure transmitting chamber when the actuation of the master piston is assisted by an assisting device, a second valve mechanism for hydraulically closing a second pressure transmitting chamber after the pressure in the first pressure transmitting chamber reaches a predetermined value, and for hydraulically connecting the second pressure transmitting chamber with the first pressure transmitting chamber when the master piston is not actuated by the assisting device.

Abstract: A self contained, supplemental vacuum assist unit is provided for use with a vacuum brake booster and a source of vacuum in a motor vehicle. The unit includes, within a single housing, an electric motor, an air pump driven by the motor, a manifold defining air exhaust and assist vacuum chambers, a pair of check valves permitting air flow from the pump outlet and the assist vacuum chamber to the air exhaust chamber, an outlet from the air exhaust chamber with a fitting for connection to the vacuum source, an opening from the assist vacuum chamber with a fitting providing communication directly to the interior of the vacuum chamber of the booster, and a pressure sensor including a diaphragm, plunger, magnet with a Hall effect sensor and motor control circuitry on a circuit board within the assist vacuum chamber. The unit is compact, light weight and efficient and is designed for attachment directly to the booster with no intervening vacuum hose therebetween.

Abstract: A braking device having a flange (21) of master cylinder (2) secured to a pneumatic booster (1) by a nut (3) screwed onto a through-bolt (13) that extends through a front shell (111) and a rear shell (112). The through-bolt (13) has a threaded front end (131) and a shoulder (132) for holding a front wall (111) in alignment with the master cylinder (2). The nut (3) has a barrel engaged in a hole (211) in the flange (21) and is screwed onto the front end (131). A collar (32) on the nut (3) acts on the flange (21) to press the flange (21) against the front shell (111). The barrel (31) of the nut and shoulder (132) of the through-bolt (13) have first and second respective sections (S1, S2) which face each which engage the front shell (111) with the first section (S1) being larger than the second section (S2) such that the front shell (111) crumples on receipt of a impact force.

Abstract: A reservoir assembly for a vehicle hydraulic braking system includes two chambers (2, 3) for the storage of hydraulic fluid. The reservoir assembly is provided with a structure for increasing the effective volume of one of the chambers (2), for example a bellows (12) or a bucket (30), and which may be operable in conjunction with the fitting of a filler cap (17) to seal a filler opening (5) for that chamber. This enables a volume of fluid to be accommodated in a chamber of increased volume, thereby substantially eliminating the possibility of volume in excess of a given volume from overflowing from the chamber (2, 3). When the reservoir assembly is installed in a vehicle braking system of a brake-by-wire electro-hydraulic type (EMB) having a first power circuit (51), and a second back-up hydrostatic circuit (60), the one chamber (2) supplies fluid to the hydrostatic circuit, and the other chamber (3) supplies fluid to the power circuit.

Abstract: A master cylinder (32) in a vehicle hydraulic braking installation uhydraulic-fluid supply device for actuating wheel brake cylinders (20). The master cylinder (32) being isolated from the wheel brake cylinders (20) by at least one shut-off valve (30). The master cylinder (32) being associated with a simulator (46) having a piston (50) located in a simulator chamber (56). The piston (50) being subjected to fluid pressure of brake fluid from the master cylinder (32) and an elastic element (52). The master cylinder (32) being of the having a primary piston (44) and a secondary piston (60) slidably located in a bore (45) of a housing (48). Bore (45) has a peripheral groove (72) which is associated with a land (68) on the secondary piston (60) to allow communication with the simulator chamber (56) when the master cylinder (32) is in a positon of rest.

Abstract: A push rod of a vacuum booster includes an inner rod section, a pipe-shaped outer rod section which is slidably fitted over an outer periphery of a rear portion of the inner rod section and connected to a brake pedal, and a buffer member made of a synthetic resin and fitted over the outer periphery of the inner rod section in front of the outer rod section. Usually, an end face of the outer rod section is retained in a position in which it abuts against a projection of the inner rod section. When an axial compressing force is applied to the push rod upon a collision of an automobile, the end face of the outer rod section slides forwards over and past the projection, while buckling the buffer member. Thus, the pushing-up of the brake pedal toward a vehicle compartment due to the retreating movement of a master cylinder is prevented, and the load applied to a driver's foot is alleviated.

Abstract: A hydraulic power conversion device includes a main oil container having an inlet for supplementing hydraulic oil, a pair of hydraulic pumps connected to the main oil container, a motor drivingly connected with the hydraulic pumps, a twin-circuitry hydraulic cylinder mechanism including a first hydraulic cylinder, a first piston, a piston rod, a sealer, a second piston, a high pressure leakage proof packing and a second hydraulic cylinder, the first hydraulic cylinder having same length as the second hydraulic cylinder but having a smaller diameter than the second hydraulic cylinder, the first hydraulic cylinder being connected with the second hydraulic cylinder by screws, the sealer being fitted between the first and second hydraulic cylinders to form two regions, the second hydraulic cylinder having an inlet provided with a first check valve only allowing hydraulic oil to flow into the second hydraulic cylinder and an outlet provided with a second check valve only allowing hydraulic oil to flow out of the s

Abstract: The invention relates to a hydraulic brake system having a tandem master cylinder as the brake force set-point value transducer for braking by external force, downstream of which are disconnection valves for hydraulically disconnecting the master cylinder from wheel brake cylinders for external force braking. To achieve a pedal travel when the disconnection valves are closed, the invention proposes a lengthened idle travel of the pistons of the master cylinder, for instance by increasing a valve opening stroke of central valves integrated with the pistons. A travel-dependent pedal force is realized with simulator spring elements that act upon the pistons.

Abstract: The present invention is directed to a hydraulic brake apparatus for applying braking force to each wheel of a vehicle in response to depression of a brake pedal. An auxiliary pressure source is provided for pressurizing the brake fluid in the reservoir to discharge power pressure. A control piston is slidably disposed in a cylinder body ahead of a master piston to be movable in response to movement thereof, so that a regulator chamber is defined ahead of the control piston, and a rear end thereof is exposed to a pressure chamber. A first pressure receiving device is operatively connected with the control piston for applying thereto first counter brake pressure having a first pressure characteristic, with the power pressure received from the auxiliary pressure source, against the hydraulic brake pressure generated in the pressure chamber and applied to the control piston.

Abstract: A boosted braking device for a motor vehicle having a master cylinder (200) and a pneumatic booster (100). The master cylinder (200) is equipped with a primary piston (30) which receives an actuating force to increase pressure in a primary hydraulic circuit (I) which increases an increase in pressure in a secondary hydraulic circuit (II) and a secondary piston (31) which is subjected to the hydraulic pressure in the primary circuit (I). The pneumatic booster (100) is controlled by the application of an input force through which an actuation force is applied to the primary piston (30). The primary piston (30) has a hollow cylinder (200) the interior of which is in communication with the primary hydraulic circuit (I). A reaction piston (34) which slides in a leaktigth fashion inside of the hollow cylinder (200) urged toward the master cylinder by a first elastic force provided by a first elastic member (46).

Abstract: In a hydraulic boosting device of the present invention, when the pressure stored in an emergency accumulator is less than a set pressure, a stepped piston 70 moves downward, a throttle valve 72 is set in a first position where the throttle valve 72 is seated in a valve seat 71, and hydraulic fluid flowing from a pump through an inlet path 14 is restricted by a flow limiting valve 68 so as to develop a fluid pressure in an annular path 73. The fluid pressure is stored in the emergency accumulator through a path 69, an accumulator valve 27, and an accumulator path 31. When the pressure stored in the emergency accumulator exceeds the set pressure, the stepped piston 70 moves upward, the throttle valve 72 is set in a second position where the throttle valve 72 is apart from the valve seat 71, and the hydraulic fluid from the pump is not restricted by the flow limiting valve 68 at all so as to flow freely toward a control valve. In this state, no fluid pressure is developed in the annular path 73.

Abstract: A brake pedal (1) for actuation of a brake cylinder (10) of a motor vehicle, comprises a lever (2), having at an end portion of one lever (3) a stepping plate (4) for actuation by a driver, and an articulation location (5) for introducing actuation forces into the brake cylinder (10), characterized in that the lever (2) comprises a first rotational axis (6) and a second rotational axis (7), the lever (2) rotating about the first rotational axis (6) during a normal actuation, and the lever (2) rotating about the second rotational axis (7) during an emergency actuation.

Abstract: A fluid-mechanical actuator has a cylinder housing and a piston which is guided movably in the cylinder housing. A working chamber can be filled with a fluid and is bounded by the cylinder housing and the piston. By filling the working chamber with fluid, the piston can be displaced in the cylinder housing counter to the effect of a restoring spring and can transmit a force via a working linkage which is arranged on the side of the piston remote from the working chamber. The fluid-mechanical actuator provides both fluid actuation and mechanical actuation. The piston has two sections, a ring and a bushing which is guided out of the working chamber. The working linkage has a supporting ring whose diameter is larger than the inside diameter of the bushing. Thereby a force can be transmitted to the supporting ring by the piston. An actuating linkage is guided in the bushing and is movable relative to the working linkage.

Abstract: A brake cylinder means (1) for a motor vehicle, comprises a cylinder/piston means (2) adapted to be operated by a brake pedal means for generating pressure in a hydraulic brake system of the motor vehicle, characterized in that the cylinder/piston means (2) is provided in an outer cylinder means (3) in an axially movable manner, a spring means is provided to resiliantly bias said cylinder/piston means (2) against said outer cylinder (3), in an normal actuation position said cylinder (2a) of said cylinder/piston means (2) being essentially non-movable with respect to the piston (2b) of said cylinder/piston means (2), such that the cylinder/piston means (2) being movable against the spring forces of said spring means (4) in said outer cylinder (3).

Abstract: A braking unit includes an intensifier mechanism for intensifying a braking liquid pressure of a master cylinder upon failure of a liquid pressure booster. The braking unit comprises the intensifier mechanism for intensifying the braking liquid pressure of the master cylinder when actuated, and a control valve which makes the intensifier mechanism operable upon failure of the liquid pressure booster. The control valve comprises a valve member which is urged by a spring tensioned with a given load and which is urged in the opposite direction from the spring by a liquid pressure of a power chamber of the liquid pressure booster. The valve member makes the intensifier mechanism operable whenever the resilience of the spring exceeds the urging force produced by the liquid pressure in the power chamber of the liquid pressure booster. This prevents an operational lag of the intensifier mechanism in the event the liquid pressure booster fails.

Abstract: A closed loop fully self-contained actuation system for converting a mechanical input motion into a mechanical output motion, which actuates a device such as a flight control surface on an aircraft, comprises an input actuator including a first fluid pressurizing means responsive to the mechanical input motion, and an output actuator including a second fluid pressurizing means, as well as a flexible fluid line extending between the first and second fluid pressurizing means to provide fluid communication therebetween. The second fluid pressurizing means is responsive to fluid flow through the fluid line, thereby initialing the output motion. The system is advantageous because it requires no hydraulic pumps, no accumulators, no reservoirs, and no dynamic seals or mechanical joints, permitting great reliability. The actuation system may be easily folded in conjunction with the apparatus on which it is employed, for compact storage.

Abstract: A brake pressure control device (1) is described in which a low-pressure valve (19) and a high-pressure valve (29) are both actuatable by a brake pedal, resulting in a brake circuit (36) being connectible alternatively either to a reservoir (23) or to a pressure source (33, 34) by releasing or depressing the brake pedal. In order to allow control of the brake pressure by an electronic control, a valve piston (17) operating the high and low pressure valves (19, 29) is movable by an electromagnet (15) independently of the actuating position of the brake pedal, into a position in which the brake circuit (36) is connected to the reservoir (23) and the connection to the pressure source (33, 34) is closed.

Abstract: A closed loop fully self-contained actuation system for converting a mechanical input motion into a mechanical output motion, which actuates a device such as a flight control surface on an aircraft, comprises an input actuator including a first fluid pressurizing means responsive to the mechanical input motion, and an output actuator including a second fluid pressurizing means, as well as a flexible fluid line extending between the first and second fluid pressurizing means to provide fluid communication therebetween. The second fluid pressurizing means is responsive to fluid flow through the fluid line, thereby initialing the output motion. The system is advantageous because it requires no hydraulic pumps, no accumulators, no reservoirs, and no dynamic seals or mechanical joints, permitting great reliability. The actuation system may be easily folded in conjunction with the apparatus on which it is employed, for compact storage.

Abstract: A hydraulic brake booster (10) includes a housing (12) which defines a pressure chamber (16) and a piston (18) within the housing (12) is movable in response to pressurized fluid within the pressure chamber (16) to effectuate a brake application. The piston (18) encloses a storage chamber (60) and forms a pair of passages (80, 90) communicating the storage chamber (60) with the pressure chamber (16). A valve member (100) is disposed within the first passage (80) in order to control communication between the storage chamber (60) and pressure chamber (16). The valve member (100) permits pressurized fluid within the pressure chamber (16) to be communicated to the storage chamber (60) in order to charge the storage chamber (60). The valve member (100) also permits high pressure fluid above a predetermined pressure level within the storage chamber (60) to be communicated to the pressure chamber (16).

Abstract: A hydraulic power booster having a lever device disposed in operative association with a reaction piston, a power piston and a valve spool, for moving the valve spool in one of opposite axial directions thereof for applying a pressure of a pressure source into a power chamber to advance the power piston, in response to a relative movement between the reaction and power pistons. The booster is provided with a backup actuator including a cylinder, and a valve drive piston which slidably engages the cylinder. The cylinder and the valve drive piston cooperate with each other to define a first fluid chamber communicating with the power chamber, and a second fluid chamber communicating with a pressure chamber in which a pressure is generated according to an advancing force of the power piston.

Abstract: A tandem master brake cylinder has first and second pistons, each piston associated with a fluid chamber and a pressure chamber. The pistons are displaced in response to actuation of a brake pedal. A hydraulic booster is coupled to a power source and is operable to enhance the piston movement and for conducting pressurized fluid to a second of the fluid chambers associated with a second piston to displace that piston in a manner reducing the volume of the pressure chamber associated with the first piston. In the event that a negative pressure is communicated with the second fluid chamber, e.g. by a loss of pressurized fluid from the power source, brake fluid is supplied through a one-way check valve to the second fluid chamber to prevent the negative pressure from reversing the motion of the second piston.

Abstract: The hydraulic brake booster (12) of the present invention comprises a full power hydraulic brake booster (12) that provides false travel during full power operation and improved pedal feel during manual operation. The booster (10) has a housing (24) with a slidable sleeve assembly (60) therein, the assembly (60) housing a sleeve member (98) which is displaced by accumulator fluid pressure against a collet housing (78) and a moveable collet member (79) located about an input member (94). The sleeve member (98) displaces the moveable collet member (79) against a resilient member (77) when the sleeve member (98) is displaced by hydraulic fluid pressure from the accumulator (14).

Abstract: An electronically controlled brake device for controlling a brake pressure according to a manual input. While the dynamic pressure line is functioning normally, the dynamic pressure acts on one end of a push rod associated with a brake pedal to give such a force as to counteract the control input to the brake pedal. If the dynamic pressure line fails, the push rod comes into contact with a dynamic pressure piston to transmit the control input force to a master cylinder. An electronic pressure control valve is provided to adjust the connection of the dynamic pressure source with a reservoir and with a dynamic pressure chamber in response to the commands of an electronic control unit so that its output pressure will be in a predetermined relationship with the pedal stroke. Thus in normal conditions, a desired deceleration is obtained with a shorter pedal stroke and in the failure of dynamic pressure, a minimum deceleration is obtained with a lighter pedal force.

Abstract: The assembly is composed of a vacuum pneumatic booster (1), a master cylinder (3) and a reservoir (5) of fluid under low pressure which feeds the master cylinder, and is intended to convert a force exerted on a control pedal into a fluid pressure supplying at least one fluid motor. The booster (1) has at least one chamber connected to a vacuum source via a non-return valve (30). This chamber is connected to the source via a duct (21) formed in the master cylinder (3), the non-return valve (30) being arranged at the outlet of the duct (21). The non-return valve (30) is arranged at the end of a pipe (25), the other end of which is connected in a sealed manner to the duct (21), the non-return valve (30) and the pipe (25) being incorporated into the reservoir (5).

Abstract: An electrically driven master cylinder assembly and various vehicle control systems utilizing the master cylinder assembly. Several forms of master cylinder assemblies are disclosed. In the preferred form, the assembly includes an electric DC motor directly coupled to a master cylinder unit with the central axis of the motor coaxial with the central axis of the bore of the master cylinder, a ball nut is positioned within the housing of the electric motor for rotation with the armature of the motor, and a ball screw is positioned on the axis of the motor and is driven linearly in response to rotation of the armature.

Abstract: A brake actuating device for automotive vehicles comprises a hydraulic brake force booster and a hydraulic tandem master cylinder to which pressure is applied by the brake force booster and which is in communication with the hydraulic wheel brake circuits. The hydraulic piston of the brake force booster applies pressure to the primary master piston of the said hydraulic tandem master cylinder. Pressure is applied to the hydraulic piston of the hydraulic brake force booster from a hydraulic pressure source through a normally closed opening valve which, through a function electronic unit receiving by way of a control input in the form of a guide quantity, an input signal representative of the pedal travel is alternately opened and closed. Accordingly the hydraulic brake pressure build-up is effected in accordance with a predetermined function stored in the function electronic unit between pedal travel and brake pressure with no lost motion of the brake pedal.

Abstract: The hydraulic booster device controls a ball valve (25) to establish a communication between a source of fluid at high pressure (35) and a braking circuit (29) during a normal braking. In the event of failure of the high pressure source (35), the braking is ensured by pressurizing of the fluid contained in a chamber (33) by a piston mechanism (20), and transfer of this fluid into the circuit (29). An additional useful volume of brake fluid is supplied to the circuit (29) by fluid expelled from the chamber (11) by the penetration of the plunger (5) into this chamber, after the piston mechanism (20) has come to a stop against the end fitting (3). Application to a hydraulic braking circuit for automobile vehicle.

Abstract: The device comprises a tandem master cylinder, a booster high pressure fluid distributor, 2, a valve mechanism 4 to interconnect the master cylinder and the distributor selectively to a braking circuit. The high pressure circuit is connected to the pipeline 46 which controls the plungers 52, 56 acting on the ball valves 50, 51 respectively. In the event of failure of the high pressure circuit,the valves 50, 51 connect the pipeline 26 directly supplied by the master cylinder and the pipeline 5 which supplies a brake motor 8 for a wheel. The device may be utilized in an anti-skid circuit.

Abstract: A piston assembly including a plastic piston defining a socket at its rear face and a metallic annular insert member positioned within the socket and receiving the piston rod of the piston assembly in acting to increase the effective area over which the loading from the piston rod is applied to the plastic piston so as to allow the plastic piston to be used in environments where it might otherwise fail due to the high stress loading. The annular insert also includes prongs struck from the main body portion of the insert member and coacting with an annular shoulder on the piston rod to preclude axial withdrawal of the piston rod from the piston and further includes an annular flange portion which acts to facilitate positioning of the insert member in the socket in the piston and further acts to define the fully retracted or extended position of the piston in coaction with a snap ring on the inner periphery of the associated cylinder.

Abstract: In a brake system for automotive vehicles comprising a master cylinder, wheel cylinders and a device for anti-lock control, the piston of the master cylinder is positioned in its nominal position by the variable volume of delivery of a pressure fluid source, in particular, a pump. The actual position of the piston is determined by a sensing device which is mounted on axially movable parts of the tandem master cylinder, booster, pedal assembly or other elements. The volume of delivery of the pump is adjusted so as to cause the piston of the master cylinder and, thus, the brake pedal to assume the desired position. For this purpose, the pump is connected with the pressure chamber of the master cylinder. Advantageously, it will be accomplished thereby that the brake pedal will not depress through its full travel when, during the control mode, more pressure fluid is removed from the hydraulic system, in particular from the pressure chamber of the master cylinder than the pressure fluid pump is able to deliver.

Abstract: A vehicle wheel brake system having a service braking section and a wheel lock control (ABS) section is provided. Under certain conditions the wheel lock control section may not be able to generate sufficient pressure to operate the vehicle wheel brakes when the master cylinder output pressure has been isolated from the wheel brakes. When such conditions occur, the displacement piston of the ABS control section moves to open a bypass valve which connects master cylinder output pressure to the vehicle wheel brake even though the ABS system has isolated it from that wheel brake. The bypass valve is a two-stage orifice valve arrangement which provides orifice control of master cylinder pressure during initial brake actuation and provides two stage valve opening action when the master cylinder output pressure is to be delivered to the wheel brake to actuate that brake irrespective of the attempted control of the wheel brake by the ABS section of the brake system.