Abstract: A brake device for a vehicle includes: a brake pedal having a pedal part and a lever part that rotates about a rotation shaft when the pedal part is operated; a housing that rotatably supports the lever part; a reaction force generator connected to the housing and the lever part to generate a reaction force against the lever part according to a stroke amount of the brake pedal; and a stopper configured to stop the lever part by being in contact with the lever part such that the lever part is restricted from rotating in a direction opposite to a rotation direction when the pedal part is operated.

Abstract: An electric brake device that including a pedal, a master cylinder unit including a cylinder storing hydraulic pressure therein, and a piston moved according to a pedal force of the pedal to generate the hydraulic pressure and provide a restoring force, and a pedal force adjustment unit operatively connected to the master cylinder unit to adjust the pedal force of the pedal by the hydraulic pressure, which is capable of adjusting a brake pedal feel.

Abstract: Provided is a vehicular brake apparatus capable of suppressing the occurrence of pedal shock. In this vehicular brake apparatus, a master cylinder forms a second hydraulic chamber neighboring to a first hydraulic chamber through a seal member. The seal member is arranged at a position facing the first hydraulic chamber and the second hydraulic chamber to be movable in the axial direction relative to the master cylinder. A first hydraulic pressure generating portion executes a movement restriction hydraulic pressure control such that when the operation information obtained by the operation information obtaining portion indicates that the brake operating member is not operated, the first hydraulic pressure which is higher than the second hydraulic pressure is generated in advance and consecutively, the larger a value relating to an operating amount in the operation information obtained by the operation information obtaining portion, the higher the first hydraulic pressure is generated.

Abstract: A vehicle brake device includes an elastic body being formed such that a circulation of an operation fluid is permitted from a front end to a rear end of the elastic body until a filling rate of the elastic body reaches a predetermined value in a filling area where deformation of the elastic body is stopped by restraint of a control piston in a state where a forward stroke of the control piston is less than at least a predetermined stroke, but the circulation of the operation fluid is stopped when the filling rate reaches the predetermined value or more.

Abstract: A hydraulic brake system includes a piston that separates a first pressure chamber from a second pressure chamber of a cylinder bore. A valve within a piston bore is movable between three positions. In the first position, the first and second pressure chambers are in fluid communication with a low-pressure fluid supply; in the second position, the second pressure chamber is isolated from the first pressure chamber and the low-pressure fluid supply; in the third position, a high-pressure fluid supply is in fluid communication with the second pressure chamber, allowing high-pressure fluid to flow into the second pressure chamber. High pressure in the second pressure chamber moves the boost piston, applying boosted braking pressure to a vehicle brake. Pressure in the second chamber against a surface of the valve biases the valve toward the first position.

Abstract: Disclosed herein are an electro-hydraulic brake and a control method thereof which provide hydraulic braking force to transfer a stable pedal feel and provide regenerative braking to improve fuel efficiency. The electro-hydraulic brake includes a master cylinder, a housing including a booster chamber and a base chamber, an oil reservoir, a hydraulic control unit connected to the oil reservoir, a simulation unit, and a pedal displacement sensor. The hydraulic control unit includes an accumulator, a pump to absorb oil from the oil reservoir and to discharge the oil to the accumulator, a motor to drive the pump, a normal cut valve, a simulation control valve, two control valves to control the pressure in the booster chamber, pressure sensors to sense the pressures in the base chamber, the accumulator and the booster chamber, and a controller to control the motor and the valves based on pressure information and pedal displacement information.

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 vehicular brake system, an input piston and a pressure piston are coaxially and axially movably supported in a cylinder, and a brake pedal is coupled to the input piston. Pressure chambers formed on the axially opposite sides of the input piston communicate with each other via a communication passage. A control oil pressure can be supplied to a first supply port of the communication passage, and a reaction-force oil pressure can be supplied to a second supply port of a reaction-force chamber of the input piston, while braking oil pressures can be delivered from delivery ports of the respective pressure chambers.

Abstract: A stroke simulator generates a reaction force in response to the operation of a brake pedal. The stroke simulator includes a stroke simulator housing, a stroke simulator piston, disposed slidably in the housing, which divides the interior of the stroke simulator housing into a first volumetric chamber and a second volumetric chamber, a stroke simulator spring, disposed in the second volumetric chamber, which generates a reaction force in response to the operation of the brake pedal by elastic deformation caused by the sliding of the stroke simulator piston, and a first supply port and a second supply port, provided for the first volumetric chamber and the second volumetric chamber, respectively, which are capable of supplying the operating oil pressure into the respective volumetric chambers when the brake pedal is operated.

Abstract: In a vehicular brake system, an input piston and a pressure piston are coaxially and axially movably supported in a cylinder, and a brake pedal is coupled to the input piston. Pressure chambers formed on the axially opposite sides of the input piston communicate with each other via a communication passage. A control oil pressure can be supplied to a first supply port of the communication passage, and a reaction-force oil pressure can be supplied to a second supply port of a reaction-force chamber of the input piston, while braking oil pressures can be delivered from delivery ports of the respective pressure chambers.

Abstract: An input rod and an input piston are advanced in response to an operation of a brake pedal, and an electric motor is driven according to the movement of the input piston to push a primary piston forward in a master cylinder through a ball-screw mechanism, thereby generating desired hydraulic pressures in a primary chamber and a secondary chamber and supplying the hydraulic pressure to the brake caliper of each wheel. At this time, a part of the hydraulic pressure in the primary chamber is received by the input piston to feed back to the brake pedal a part of the reaction force of hydraulic pressure during braking. A retainer of a spring assembly interposed between the primary and secondary pistons has a hollow structure to insert therein the forward end portion of the input piston, thereby allowing a reduction in the axial length of the primary piston.

Abstract: The present invention provides a vacuum booster, which is constructed such that an area with which a cylinder communicates with a port communicating with a reservoir and being open to the cylinder is reduced at high temperature, so that a sufficient reaction force can be transmitted from a piston of a master cylinder to a valve mechanism at an initial stage of the braking operation, thus preventing vibration or noise from being generated in the valve mechanism. At high temperature, stop position, at which backward movement of the piston of the master cylinder is limited by an output member while a valve piston is at a non-operating position, is shifted forwards by a stop position shifting means, thus reducing the area with which the cylinder communicates with the port communicating with the reservoir and being open to the cylinder.

Abstract: The invention provides a method and apparatus wherein the apparatus includes a housing having a first end and a second end. The housing also includes a first aperture and a second aperture. The first aperture is positioned to communicate with a first fluid source at a first pressure. The second aperture is positioned to communicate with a second fluid source at a second pressure. The first pressure is greater than the second pressure. The apparatus also includes a first piston disposed in the housing. The first piston is moveable between the first and second ends. The first piston includes a front surface communicating with the second aperture and a back surface communicating with the first aperture. The first piston also includes a first passageway communicating with the front and back surfaces. The apparatus also includes a three-way valve fluidly disposed between the first aperture and the back surface and between the front surface and the back surface.

Abstract: There is provided a vehicle braking device in which a front outer periphery of a backup piston that can directly press a master piston from behind when output fluid pressure from a fluid pressure generation source is reduced is fluid-tightly and slidably fitted to a short cylindrical separator, a sleeve forming an annular channel between itself and an outer periphery of the backup piston is placed backward of the separator, and annular seal members for sealing front and rear sides of the annular passage are mounted between the separator and the backup piston, and between the sleeve and the backup piston. The seal member for sealing a front side of the annular passage is mounted to an inner periphery of the separator so as to come into repulsive contact with the outer periphery of the backup piston. The seal member for sealing a rear side of the annular passage is mounted to the outer periphery of the backup piston so as to come into repulsive contact with an inner periphery of the sleeve.

Abstract: In a vehicle braking system, a backup piston pushes a master piston directly from behind when hydraulic pressure of a boosted hydraulic pressure chamber decreases. The backup piston has a piston body which is slidably fitted in a casing, and a pusher which is slidably fitted in the casing with a seal diameter smaller than seal diameters of the master piston and the piston body and which extends to the front end of the piston body, to push the master piston from behind. An annular input chamber communicated with a hydraulic power source is formed between the backup piston and the casing. When the pusher pushes the master piston forward, amount of volume increased in the boosted hydraulic pressure chamber is set to be substantially equal to amount of volume decreased in the input chamber. Thus, it is possible to avoid increase in the hydraulic pressure of the boosted hydraulic pressure chamber during forward movement of the backup piston, using a simple configuration with a reduced number of parts.

Abstract: A hydraulic controller includes: a pair of liquid chambers; and an on-off valve capable of opening and closing a flow channel on the side of the liquid chamber with a higher hydraulic pressure out of the pair of liquid chambers. The flow channel can provide communication between the pair of liquid chambers. A baffling device is provided in the liquid chamber with a lower hydraulic pressure, to baffle hydraulic fluid flowing from the liquid chamber with the higher hydraulic pressure. Thus, it is possible to reduce operating noise resulting from operation of the on-off valves.

Abstract: A pneumatic brake booster for use in a motor vehicle having a feeler (42) mounted to slide on a plunger (32) located at the end of a control rod (22) and pivoting key (62) for axially blocking the movement of the feeler (42) with respect to the plunger (32) during a normal brake application and unblocking the movement during an emergency brake application to reduce the length of a plunger-feeler assembly and thus increase the jump phase of an output force.

Abstract: The present invention is directed to a master cylinder having a braking stroke simulator, wherein a master piston is slidably accommodated in a housing having an atmospheric pressure chamber and a master pressure chamber, and a simulator piston is slidably accommodated in the housing to define a simulator chamber. An elastic member is provided for applying a stroke of the simulator piston in response to braking operation force applied to a manually operated braking member. Thus, the braking stroke simulator transmits the braking operation force to the master piston through the simulator piston and elastic member. A cut-off seal member is disposed in the housing for supporting the master piston, and placed to be applied with the pressure in the master pressure chamber in front of it and applied with the atmospheric pressure behind it. And, a passage is formed in the master piston to communicate the simulator chamber with the atmospheric pressure chamber when the master piston is placed in its initial position.

Abstract: Braking device including a master cylinder (2), a primary piston (3), a control member (4), a booster (6) coupled to the control member (4), and an assist valve (VA) defined by a reaction piston (17) with a bore (18) therein for receiving a ratio control member (24). The control member (24) has a piston (29) with a head (25) located in a chamber (26) between the reaction piston (17) and a bushing (27) retained in the bore (18). The bushing (27) has an axial passage (28) that receives a head (25) of piston (29) to form a valve (36) for closing an inlet to a passage (30) in the piston (29). The bushing (27) slides within bore (18) to limit a pressure difference between the chamber (26) and a front part (18a) of the bore (18) to a value below a pressure difference that causes the valve (36) to open.

Abstract: A negative pressure type brake hydraulic pressure generating device is proposed in which the stroke on the operating side can be set independently of the stroke on the output side. A slide resistance imparting means is provided between the fixed shell and a piston having a built-in control valve introducing atmospheric air to cancel the slide resistance which is the cause of increased stroke hysteresis of the piston, i.e. the slide resistance applied to the piston at airtight seal portions between the power plate and the piston.

Abstract: A vehicle hydraulic brake apparatus includes a hydraulic pressure generator which generates a power pressure irrespective of operation of a brake pedal and a regulation valve which regulates the power pressure to a predetermined pressure corresponding to an operation force of the brake pedal and outputs it to an output chamber. A master cylinder generates a master cylinder pressure in a master cylinder chamber by forward movement of the master cylinder piston and a wheel brake cylinder is operated by the master cylinder pressure to apply braking force to a vehicle wheel. An auxiliary piston is located backward the master cylinder piston to define an auxiliary pressure chamber between the master cylinder piston and the auxiliary piston and to move the master cylinder piston forward by an auxiliary pressure in the auxiliary pressure chamber. A pressure modulating device decreases the predetermined pressure outputted from the output chamber to supply the auxiliary pressure to the auxiliary pressure chamber.

Abstract: A hydraulic brake booster (12) having a housing (100,200) with a first bore (102) separated from a second bore (104). The first bore (102) retains a power piston (50) and the second bore (104) retains a control valve (60). The first bore (102) is connected by a passage (112) to the second bore (104) that is connected to a source of pressurized supply fluid (24). In responsive to a desired braking force being applied to the input member (30,30′), the lever arrangement (80) moves the control valve (60) to allow controlled pressurized supply fluid to be communicated from the second bore (104) by way of passage (12) to the first bore (102).

Abstract: In a braking pressure intensifying master cylinder, as an input shaft (53) travels forwards in a braking maneuver, a control valve (54) is actuated to develop fluid pressure according to the input in a reaction chamber (38) and a pressurized chamber (35). A stepped spool (45) as a part of the control valve 54 travels such that force produced by the fluid pressure and spring force of a spring (51) are balanced, whereby the stepped spool (45) can function as a travel simulator. By changing the pressure receiving areas of the stepped spool and/or changing the spring force of the spring (51), the travel characteristic of the input shaft (53) as the input side can be freely changed independently from the output side, without influence on a master cylinder pressure as the output side of the braking pressure intensifying a master cylinder (1). In addition, the master cylinder pressure can be intensified when necessary with a simple structure.

Abstract: A hydraulic brake booster (12) having a housing (100,200) with a first bore (102) separated from a second bore (104). The first bore (102) retains a power piston (50) and the second bore (104) retains a control valve (60). An input member (30,30′) is connected to the power piston (50) and linked to the control valve (60) by a lever arrangement (80). The first bore (102) is connected by a passage (112) to the second bore (104) that is connected to a source of pressurized supply fluid (24). In responsive to a desired braking force being applied to the input member (30,30′), the lever arrangement (80) moves the control valve (60) to allow controlled pressurized supply fluid to be communicated from the second bore (104) by way of passage (12) to the first bore (102). The controlled pressurized supply fluid in the first bore (102) acts on the power piston (50) to develop an operational force to effect a brake application.

Abstract: In a brake booster of the present invention, by depression of a brake pedal 3, an input shaft 4 travels to the left, a pedal input converter generates thrust, and a valve element 5a moves to the left. A valve passage 5a1 is shut off from a valve passage 5b1 and a valve passage 5a2 is connected to a valve passage 5b2 so as to develop output pressure Pr at an output port 5c of a control valve 5 because of the pressure of a pressure source. The output pressure Pr is supplied to a wheel cylinder 7, thereby actuating the brake. At this point, since the displacement of the input shaft 4 required for operating the control valve 5 is defined only by the converter 6, the input side is not affected by the brake rigidity of a circuit from the control valve 5 to the wheel cylinder 7. The output pressure Pr of the control valve 5 acts on the valve element 5a through a first reaction receiving portion 8 and is regulated to pressure proportional to the thrust of the converter 6.

Abstract: In a brake fluid pressure boosting device 1 of the present invention, by operation, an input shaft 4 is moves forward to rotate a lever 27 to actuate a control valve 8 so that the control valve 8 produce working fluid pressure corresponding to the input. The working fluid pressure is introduced into the power chamber 6. By this working fluid pressure, the primary piston 37 is actuated to develop master cylinder pressure. On the other hand, the fluid pressure of the power chamber 6 is introduced into the first annular groove 25 of the valve spool 10. By the difference between pressure receiving areas of the first annular groove 25, the valve spool 10 is subjected to rightward force. The position of the pivot of the lever 27 is fixed and the valve spool 10 is controlled in such a manner that the force applied to the valve spool 10 and the spring force of the spool return spring 32 balances with the input, thereby exhibiting the function as a stroke simulator.

Abstract: A master cylinder for vehicle braking systems includes a housing having a central cavity, at least one fluid supply inlet port, at least one pressure outlet port, and a flange at one end thereof. A piston actuation mechanism within the central cavity is moveable between a first position wherein the central cavity is in fluid communication with the fluid supply inlet and a second position where the central cavity is in fluid communication with the pressure outlet. A cup-shaped end cap is fastened to the housing flange in a fluid sealing relationship wherein the cup-shaped end cap receives at least a portion of the piston actuating mechanism therein and further retains the piston actuation mechanism in an operational configuration within the housing.

Abstract: A brake system including a negative pressure booster, a master cylinder of tandem type and an intensifying arrangement. The intensifying arrangement defines an intensifying chamber disposed rearward of a primary piston, a pump for supplying a braking liquid to the intensifying chamber, and a reaction piston and a sleeve for controlling the pressure of the braking liquid which is supplied to the intensifying chamber. As a brake pedal is depressed and the intensifying arrangement is actuated, a sum of an urging force from the negative pressure booster and an urging force from the intensifying arrangement operates the primary piston to develop a master cylinder pressure. The sum is proportional to the input or a force depressing the brake pedal.

Abstract: A pedal simulator utilizing springs to provide a brake pedal with a non-linear, progressively increasing response characteristic for pedal travel versus force exerted on the brake pedal similar to a conventional hydraulic braking system. In a preferred embodiment, the pedal simulator is integrated into the housing of an associated master cylinder. The non-linear, progressively increasing response characteristic is provided in one embodiment by a conical spring having a non-uniform helix angle. In second and third embodiments, the non-linear, progressively increasing response characteristic is provided by a plurality of cylindrical coil springs.

Abstract: A counter-force mechanism (37), which produces a counter force when a brake booster is operated, is made up of an input-side member (38) slidably disposed within a valve body (3), a second constant-pressure chamber (39) formed on the rear side of the input-side member and into which a pressure is introduced from a constant pressure chamber (A), and a second constant-pressure chamber (39) formed on the front side of the input-side member and into which a pressure is introduced from a variable pressure chamber (B). The counter force from the counter-force mechanism (37) is reduced by an orifice passage (43) as a counter-force reducing means in rapid operation of the brake.

Abstract: A brake reaction which occurs as a brake booster is actuated is prevented from being transmitted to a brake pedal, and instead pseudoction reaction imparting means 41 is provided to transmit a pseudo-reaction to the brake pedal. A valve body 5 and a power piston 3 are capable of relative movement in the axial direction, and are normally urged away from each other by a spring 8. The valve body 5 is normally urged forward by a spring 42 which is disposed within the variable pressure chamber B. This arrangement allows a variation in the advancing stroke of the brake pedal to be suppressed small if a variation occurs in the magnitude of a negative pressure which is introduced into a constant pressure chamber A as the brake booster is actuated, thus providing an improved brake feeling experienced by a driver.

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 brake booster which permits an axial relative movement between a power piston and a valve body is disclosed. An arrangement is made which prevents a brake reaction from being transmitted to a brake pedal. As an alternative therefor, pseudo-reaction imparting means transmits a pseudo-reaction to a brake pedal. A rear end of the valve body is covered by a tubular cover and bellows connected thereto, and its internal space is maintained in communication with a constant pressure chamber. The bellows has an effective diameter which is chosen to be of an equal size to the diameters of a vacuum valve seat and an atmosphere valve seat. This allows a pseudo-reaction and a brake pedal stroke to be obtained which depend on the force with which a brake pedal is depressed if a negative pressure within the constant pressure chamber varies, thus imparting a better brake feeling to a driver.

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. A master piston is received in a cylinder body to define a pressure chamber ahead of the master piston and a power chamber behind it. An auxiliary pressure source is provided for pressurizing the brake fluid in a reservoir to discharge power pressure. A control piston is slidably disposed in the cylinder body ahead of the 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 the pressure chamber. A first passage is adapted to communicate the auxiliary pressure source with the power chamber, and a second passage is adapted to communicate the power chamber with the reservoir through the regulator chamber.

Abstract: A master cylinder and pneumatic brake booster having hydraulic reaction means. The hydraulic reaction means which is mounted to slide within a main piston (12) in the master cylinder includes a central shut-off piston (4), a stepped and hollow reaction piston (5) and a ratio-change piston (6). First (71), second (72) and third (73) springs are associated with said hydraulic reaction means such that a push rod (3) receives only a portion of a reaction force is an actuation force is applied rapidly which is proportional to a difference between an internal cross section of the reaction piston (5) and an external cross section of the reaction piston (5).

Abstract: A vehicle brake booster apparatus includes a housing and a power piston positioned within the interior of the housing to divide the interior into a first pressure chamber and a second pressure chamber, with the power piston being movable in response to a pressure difference between the second pressure chamber and the first pressure chamber. An axially movable input rod extends outwardly from the power piston and is adapted to be operatively connected to a brake pedal. An axially movable output rod extends outwardly from the housing and is adapted to be operatively connected to a master cylinder. An axially movable valve plunger is mounted within the power piston and is operatively connected to the input rod. A control valve is disposed within the power piston and controls the pressure difference between the first pressure chamber and the second pressure chamber.

Abstract: A boosted braking device having a master cylinder and a pneumatic booster wherein the force for actuating the master cylinder is derived from a combination of an input force and a boost force of the booster. A main hydraulic piston of the master cylinder has a holler cylinder for receiving the input force. A secondary hydraulic piston located within the holler cylinder of the main hydraulic piston receives a hydraulic reaction force to impart an increasing braking force corresponding to an input force applied over an entire travel of a brake pedal.

Abstract: In a brake-pressure producing device of the present invention, a power piston 10 of a hydraulic booster 2 comprises a stepped piston including a large-diameter portion 10a on which fluid pressure of a power chamber 30 is exerted and a small-diameter portion 10b having the same diameter as the master cylinder piston 53. Both the pistons 10, 53 are interlocked with each other through an aligning rod 62. The pressurized fluid of the power chamber 30 is introduced into an annular chamber 51 formed on the circumference of the small-diameter portion 10b and the fluid pressure of the pressurized fluid is exerted on a stepped portion 10c between the large-diameter portion 10a and the small-diameter portion 10b in the direction opposite to the direction of the fluid pressure of the power chamber 30.

Abstract: According to the invention, the booster is not provided with a brake reaction transmission mechanism, and hence a reaction cannot be transmitted to a brake pedal. On the other hand, a pseudo-reaction imparting means is provided to impart a pseudo-reaction of suitable magnitude which depends on the degree of depression of the brake pedal. The pseudo-reaction imparting means is arranged so that when the brake pedal is depressed relatively rapidly, a relatively smaller braking reaction is imparted than during a usual depression. With this arrangement, the transmission of an abnormally high braking reaction to a driver which is experienced in a conventional booster during a quick braking operation due to an operational rag of the booster is avoided.

Abstract: A hydraulic power booster for a brake apply system includes a mechanically actuated hydraulic booster of compact design that can be integrated in line with a conventional type master cylinder. Additionally, a combination of twin mechanically actuated check valves is arranged to provide a structure with essentially no leakage when the hydraulic booster is at rest and when the hydraulic booster is at poise. A mechanically actuated check valve is normally held open and is positioned in a passageway between the power piston and a fluid reservoir. This check valve is substantially, immediately closed upon the application of force to the brake pedal. Another mechanically actuated check valve is provided in a passageway between the hydraulic power supply and the power piston. This check valve is mechanically opened to supply a selected amount of pressurized fluid to the power piston which generates a selected amount of vehicle braking in response to actuation of the brake pedal.

Abstract: An actuating unit for a hydraulic brake system for automotive vehicles includes a vacuum brake power booster and a master brake cylinder. To transmit the reaction forces, developing during actuation in the master brake cylinder, to a vehicle body wall which carries the actuating unit, a centrally positioned force-transmitting element is provided, which is arranged between the master brake cylinder and the vehicle body wall in terms of effect. The force-transmitting element is formed of a continuous bolt which extends in an axial direction through the control housing of the vacuum brake power booster.

Abstract: The valve portion of pressure control valve tends to be unstable because when the valve is opened, the valve opening pressure intensifies. To prevent this, the valve portion of the pressure control valve is in the form of a puppet valve so that the valve body of the valve portion receives the pressure of a dynamic pressure source in the valve-opening direction and receives the pressure of an fluid pressure introducing chamber in the valve-closing direction. With this arrangement, when the valve opens and the dynamic pressure source pressure drops, the valve-closing force increases, so that the pressure control valve shows a stronger tendency to close. This prevents the freefall of the pressure source pressure, so that the behavior of the valve portion stabilizes. Thus, it is possible to prevent vibrations and abnormal noise.

Abstract: A hydraulic master cylinder (1) comprises a body (2) in which conventional output chambers (5,6) are defined. In use, the output chambers are pressurized by a piston (4) which is moved by a combination of mechanical input force applied to an input member (8) and hydraulic pressure within a servo chamber (13) located to the rear of the piston (4). Connection of the servo chamber (13) to a pressure source is controlled by poppet valves (16, 17) which are opened as necessary by ribs (23, 24) of a sleeve (22) mounted on imput member (8). The sleeve (22) is coupled to the piston (4) but free to rotate relative to the input member (8) and is coupled to the input member by means of a helical groove and ball arrangement such that movement of the input member (8) towards the piston (4) causes rotation of the sleeve (22) to open the inlet valve (17), and movement of the input member ( 8) away from the piston (4) causes opposite rotation of the sleeve (22) to close the input valve (17) and open the outlet valve (18).

Abstract: A brake booster mounting including a support to which the booster is securable by means of at least one mounting bolt, and a captive nut located on a side of the support opposite to that to which the booster is to be attached and which is engageable by the bolt so as to effect attachment of the booster to the support. The captive nut is held against separation from the support and is also held against rotation by a retainer so that connection of the bolt to the nut can be effected from the side of the support to which the booster is to be attached. A pilot section on one end of the bolt locates within the captive nut so as to thereby automatically position the nut to be cooperable with a threaded portion of the bolt. The bolt also serves to hold separable parts of the booster housing against separation, and is rotatable relative to those parts to permit the booster to be attached to or detached from the support.

Abstract: A brake booster which includes a control slide that is displaceably supported in a servo piston and acted upon by a piston rod under the influence of brake pressure. The control slide has bores that establish communication between a pressure chamber and a pressure source or return for power brake fluid in the pressure chamber. The control slide is intended to penetrate a control bush in a stepped bore in the servo piston, which has a radial bore for connecting the pressure source with a radial bore in the control slide toward the pressure chamber. The control bush is supported radially movably in the stepped bore.

Abstract: An improved booster for use with a master cylinder in a brake system is proposed which includes a spring for keeping the input shaft away from the booster piston. The spring has one end abutting on a piston acted by the auxiliary pressure from the auxiliary power source and the other end abutting on the brake pedal to bear the pedal stepping force. The input shaft will not engage the booster piston except in case of the failure of the auxiliary power source, ect.

Abstract: A hydraulic brake booster including main cylinders operative relative to a pedal stroke by which a sufficient pedal stroke is still available in the event of a failure in the pressure supply so that the brakes can be actuated by the pedal stroke and furthermore flooring of the brake pedal is avoided in the event of failure of the fluid medium power supply.

Abstract: In an hydraulic booster a load applied to a master cylinder assembly through the booster is fed back to a pedal-operated input piston through a reducer mechanism. This provides, when a booster chamber for operating a boost piston is pressurized by boost pressure, a reaction of "feel" at the pedal which is unaffected by the magnitude of the boost pressure.

Abstract: A braking-force booster which contains a pressure source, a pedal operated control valve and at least one main brake cylinder; a piston which creates the brake pressure, is exposed to the pressure created in the main brake cylinder by means of the control valve, wherein the control valve, dependent on the pedal displacement, interrupts a connecting channel between the main brake cylinder and a pressureless connection and temporarily creates a second connecting channel between the pressure source and the main brake cylinder. The pedal operated control valve contains a plunger movable by the pedal which extend into the main brake cylinder, and the first connecting channel is integrated into the main brake cylinder piston. The first plunger has a valve closing member for shutting off this connecting channel during the corresponding approach.

Abstract: A brake booster is provided with a housing (30) having a bore (32) therein receiving a piston (52) carrying a valve assembly (68). An end plug (50) cooperates with the piston (52) to form a work chamber (66) and an input member (84) extends through the end plug to cooperate with the valve assembly (68). In the rest position, the work chamber (66) communicates with a reservoir (38) via passage 112, auxiliary chamber 104, passage 116, bore 32 and passage (40) independently of the piston (52).