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

Abstract: A pneumatic brake booster comprising a rigid casing (10) locally shaped into a hollow shaft (3), a hub (5) slideably mounted in an opening (30) of the hollow shaft (3), an annular seal (6) inserted between the hub (5) and the hollow shaft (3), and members designed to set the hub (5) in a rest position with respect to the hollow shaft (3). The seal (6) comprises an elastomeric material (61) shaped into an annulus and an annular metal insert (62), the position-setting members (71, 72) being partially formed by the insert (62).

Abstract: This invention relates to a sensor module, comprising a processing unit, a stroke sensor and a force sensor (3), and capable of determining, inside the associated pneumatic servomotor for an assisted braking, data concerning both the force exerted on an axially-moving rod (1), and the travel of said rod (1), by the determination of the position of the piston (2) coupled to the rod (1).

Abstract: A pneumatic brake booster for a motor vehicle, of the type in which the movements of a control rod (38) are able to determine the openings and closings of at least one axial intake valve (52) which is inserted between a pressure source subjected to the pressure (Pa) higher than the first pressure (P1) and a rear chamber (18) of the booster, and of at least one axial equalizing valve (50) which is inserted between a front chamber (16) and the rear chamber (18), to actuate a moving partition (14) inserted between the front chamber (16) and the rear chamber (18), characterized in that it comprises a tubular element (76) of which axially offset transverse faces (78, 80) comprise first elements (82, 84) for sealing the axial intake and equalizing valves (50, 52) and that the control rod (38) is able to operate via two concentric springs (40, 122) having different stiffnesses.

Abstract: A vehicle motion control device reduces noise resulting from operation of a vacuum booster when an automatic pressure control is performed by properly controlling the energization of a linear solenoid of a booster actuator. An automatic hydraulic pressure generator is controlled in accordance with the vehicle motion condition and a hydraulic pressure control valve device is controlled to perform the automatic pressure control. A target electric current of the linear solenoid for actuating the vacuum booster is instantaneously increased to a starting target value which corresponds to an electric current value immediately before starting the operation of the vacuum booster and which is less than a maximum value of the target electric current, and then is gradually increased approximately to the maximum value of the target electric current.

Abstract: Disclosed is a master cylinder wherein a seal member is given plural seal functions to reduce the number of seal members for partitioning a drain portion of the master cylinder, a constant-pressure chamber of a booster and the atmosphere from one another, so that the master cylinder is simplified in construction and reduced in manufacturing cost. When a piston is operated by an output shaft of the booster attached to a booster mounting surface of a cylinder body, the operating fluid from the fluid pressure chamber partitioned by a fluid-tight seal member is supplied to a brake system. An annular complex seal member is fit in an internal seal stepped portion which is formed by radially expanding an opening portion of the cylinder which opens to a booster mounting surface. A slide seal portion of the complex seal member partitions a drain portion behind the fluid-tight seal member from the constant-pressure chamber of the booster through sliding contact with the piston.

Abstract: A vacuum booster apparatus used for a brake apparatus positively decreases a degree of opening of a throttle valve when it is required while an unnecessary decrease in the degree of opening of the throttle valve is positively prevented. A first pressure chamber of a vacuum booster is connected to an intake pipe of the engine on a downstream side of a throttle valve. A second pressure chamber of the vacuum booster is selectively connectable to one of the first pressure chamber and atmosphere. The vacuum booster boosts an operating force applied to a brake operating member based on a pressure difference between the first pressure chamber and the second pressure chamber. A throttle-opening-degree control device controls a negative pressure in the first pressure chamber by controlling the degree of opening of the throttle valve.

Abstract: This is a new brake system for minimizing the turning radius of a vehicle when it makes a U-turn or parks. The minimum turning radius of a conventional vehicle has a certain limit because a conventional vehicle takes the Ackerman-Jeantaud steering principle. The object of this invention is to overcome the limit of the minimum turning radius by introducing the new concept, the one wheel brake system. This invention utilizes the phenomenon that if one wheel is braked, the other wheel is driven by the differential gear. Hence the vehicle circles around a braked wheel as its pivot. So it turns much smaller than the minimum turning radius of the Ackerman-Jeantaud steering angle.

Abstract: A pneumatic brake booster for a motor vehicle wherein movements of a control rod (38) determine the openings and closings of at least one axial intake valve (52) and at least one equalizing valve (50). The intake valve (52) being inserted between a pressure source subjected to the pressure (Pa) higher than the first pressure (P1) and a rear chamber (18) of the booster, and the equalizing valve (50) being inserted between a front chamber (16) and the rear chamber (18) to actuate a moving partition (14) located between the front chamber (16) and the rear chamber (18). A tubular element (76) of that is axially offset transverse faces (78, 80) comprised of first elements (82, 84) for sealing the axial intake and equalizing valves (50, 52).

Abstract: This invention mainly relates to a pneumatic servomotor for an assisted braking, which reduces the noise in the passenger space to the minimum, while not requiring much room in the engine compartment, and it also relates to a motor vehicle equipped with such servomotor.

Abstract: The problem of providing air from a vehicle engine compartment to a breather port of a vacuum booster mounted on a wall separating the engine compartment from the passenger compartment is solved by adapting the wall to provide an air passage, when the rear wall of the booster is bearing against the wall.

Abstract: The solenoid current increases at low temperatures and decreases at high temperatures because the modulus of elasticity of an elastically deformable valve body and the slide resistance of an elastically deformable seal member vary with temperatures. Therefore the solenoid current for opening the valve mechanism from a closed position is required to be changed with low and high temperatures. To supply the solenoid current necessary for opening the valve mechanism without directly measuring the temperature, the solenoid current (the boost starting current leaning value) indicated when the pressure varies with the opening of the valve mechanism is recorded at the time of pressure-increasing, and thereafter when the valve mechanism is opened again after the closing of the valve mechanism, the solenoid current computed on the basis of the pressure-increase starting current learning value thus recorded is supplied.

Abstract: A tandem pneumatic booster includes a front shell having a relatively long cylindrical portion and a rear shell having a relatively short cylindrical portion. The cylindrical portions of the front and rear shells are joined together to form a shell body. An opening edge of a cylindrical portion of a center shell is disposed in the joint between the front and rear shells, together with an outer peripheral bead of a diaphragm of a rear power piston. The cylindrical portion of each of the front, rear and center shells has a frusto-conical shape gradually increasing in diameter toward the opening edge thereof. Thus, when front shells, rear shells and center shells are stacked on one another, respectively, as constituent parts before assembly, the depth of fitting between each pair of adjacent shell elements is increased sufficiently to stably maintain the stacked conditions of the shell elements.

Abstract: A pneumatic brake booster (10) has a booster housing (12), the interior of which is subdivided by at least one movable wall (14) into a vacuum chamber (16) and a working chamber (18). Along an axis (A) a control valve (20) for controlling a pneumatic pressure difference acting upon the movable wall (14) projects into the booster housing (12). The movable wall (14) is workingly connected to the outside of a substantially cylindrical control valve housing (22), in that a collar (34) of a plate (30) associated with the movable wall (14) is deformed along its periphery at least in sections radially into the control valve housing (22). In order to simplify manufacture of the brake booster (10), in the portion (36) of the control valve housing (22) overlapped by the collar (34) of the plate (30) a plurality of recesses (40) are provided, which are spaced apart from one another in peripheral direction and into which the collar (34) of the plate (30) is radially deformed.

Abstract: A pneumatic brake booster (10), in particular for motor vehicles, is described. The pneumatic brake booster (10) has a control valve (22) for controlling a pneumatic pressure difference, a force input element (24) for actuating the control valve (22), a force output element (38) for transmitting the braking force as well as a reaction disk (34) of elastomer material disposed between the force output element (38) and the force input element (24). Disposed between the reaction disk (34) and the force input element (24) and acting upon the reaction disk (34) is a unit (30) for altering the force transmission ratio between the force input element (24) and the force output element (38) in dependence upon the force exerted upon the force input element (24). The unit (30) comprises a displaceable inner piston (50) as well as an outer piston (54), which surrounds the radially outer side of the inner piston (50) and is displaceable relative to the inner piston (50).

Abstract: Normally, at the time of cold-start of an internal combustion engine or the like, the flow of exhaust in an exhaust passage of the internal combustion engine is suppressed or two-stage combustion is carried out so as to promote exhaust purification in an exhaust system. However, when a correlation value of a braking force required to be generated by a vacuum type brake booster is greater than a correlation value of a braking force that can be aactually generated by the vacuum type brake booster, a restricting device restricts the suppression of the exhaust flow or a two-stage combustion prohibiting device prohibits the two-combustion. Therefore, it is possible to improve an exhaust emission purifying performance while ensuring a braking force by the vacuum type brake booster at the time of braking.

Abstract: A vacuum booster apparatus used for a brake apparatus positively decreases a degree of opening of a throttle valve when it is required while an unnecessary decrease in the degree of opening of the throttle valve is positively prevented. A first pressure chamber of a vacuum booster is connected to an intake pipe of the engine on a downstream side of a throttle valve. A second pressure chamber of the vacuum booster is selectively connectable to one of the first pressure chamber and atmosphere. The vacuum booster boosts an operating force applied to a brake operating member based on a pressure difference between the first pressure chamber and the second pressure chamber. A throttle-opening-degree control device controls a negative pressure in the first pressure chamber by controlling the degree of opening of the throttle valve.

Abstract: A hydraulic brake device which enables an accurate increase in the braking force after reaching the boosting limit of a brake booster includes a cylinder, a master piston, a floating piston, a master pressure chamber defined by the cylinder, the master piston and the floating piston, a brake pressure chamber defined by the cylinder and the floating piston, and a valve disposed in the master piston for establishing and interrupting a communication between the master pressure chamber and a reservoir tank. In addition, a valve actuating member is movable relative to the output member for opening the valve when moved by a predetermined amount relative to the output member in accordance with operation of the brake operation member, and a moving amount controlling mechanism reduces the relative movement of the valve actuating member in accordance with the increase of the operation force by the brake operating member.

Abstract: In a vehicle brake control device, it is determined whether a first starting condition, that a master cylinder pressure and a rate of change of the master cylinder pressure are equal to or more than respective first reference values, is satisfied. Furthermore, it is determined whether a second starting condition is satisfied based on a determination as to whether the master cylinder pressure is equal to or more than a second reference value at a time when a predetermined time has elapsed since a time when the first starting condition was satisfied . In a case where the second starting condition is determined as being satisfied, a brake assist control is executed until a termination condition of the brake assist control is satisfied.

Abstract: In order to solve the problem of the passing of an elbow piece (15) with a right-angle bend (16) through an opening (21) in a seal (19), said seal (19) is provided with a deformable slot (20). The tightness of the system, consisting of the seal (19) and the elbow piece (15), results from the existence of fir-branch shaped protrusions (27) on the base (26) of the elbow piece (15).

Abstract: The problem of providing air from a vehicle engine compartment to a breather port of a vacuum booster mounted on a wall separating the engine compartment from the passenger compartment is solved by adapting the wall to provide an air passage, when the rear wall of the booster is bearing against the wall.

Abstract: A brake booster 1 includes a valve mechanism 6, and a solenoid 8 which operates the valve mechanism 6. When the solenoid 8 is energized, a solenoid plunger 26 and a valve seat member 11 move rearward relative to a valve body 3, whereby the valve mechanism 6 is operated to actuate the brake booster 1 without depressing a brake pedal. A core member 27 which forms a magnetic path for the solenoid 8 is disposed rearward of the solenoid plunger 26 so as to be movable axially of the valve body and so as to move in linked relationship with a valve plunger 13. The invention allows the size of the solenoid 8 to be reduced.

Abstract: A brake system 1 of the present invention comprises a brake operating means 2 such as a brake pedal for carrying braking operation, a fluid variable stroke means 3 which variably controls the stroke of the brake operating means 2 by using fluid, and a braking force output means 4 which is actuated by the operation of the brake operating means 2 to produce braking forces. By manipulating the brake operating means 2, the braking force output means 4 performs the braking operation. The traveling rang of the brake operating means 2 i.e. the stroke can be changed variously by the fluid variable stroke means 3 using fluid. Since the stroke of the brake pedal can be changed as mentioned above, a proper pedal stroke can be obtained.

Abstract: The invention provides a pneumatic servomotor for an assisted braking of a motor vehicle, of the type comprising a unidirectional clutch device (56), which includes a coaxial sleeve (58), sliding on a plunger (46), and a substantially ring-shaped key (60), arranged with a given clearance around the sleeve (58) and capable of being driven by a moving piston (22), when an input force is applied at a determined speed onto a control rod (38) integral with the plunger (46), so as to rock and lock the sleeve (58) in an axial position, in which it locks a finger (52) biasing the piston (22) independently of the control rod (38), characterised in that the finger (52) is axially integral with the sleeve (58) and in that means are provided for an axial indexing of the locking position of the sleeve (58)

Abstract: The present invention discloses a brake system for automotive vehicles including a vacuum brake power booster which is operable preferably by a solenoid irrespective of the actuation by the driver. In order to sense the actuating speed during actuation introduced at a brake pedal by the driver, the present invention provides a travel sensor of proportional operation which is operable by the axial movement of the movable wall of the vacuum brake power booster, and the output signal of the travel sensor is directly proportional to the actuating travel of the movable wall and is subjected to a time differentiation processing operation in an electronic control unit.

Abstract: A motor vehicle tandem brake power booster with two booster units each including a vacuum chamber and a working chamber each arranged in a partition divided housing. The pressure difference between the pressure in the vacuum chamber and the pressure that can be influenced by a switching device in the corresponding working chamber in each booster unit acts on a piston separating the vacuum chamber from the working chamber. The forces, which are proportional to the pressure difference and act on the pistons are bundled via mechanical intermediate members by at least one transmission element each with the forces applied by the driver of the vehicle to a corresponding brake pedal.

Abstract: The invention provides a braking servomotor, comprising an actuating piston for a master cylinder, a resiliently returned control rod, sliding in the piston as a function of an input force, the end of said rod bearing a plunger on which a finger (52) is slidingly fitted so as to bias a reaction disk of the actuating rod and transmit the reaction of the piston to the control rod, and including a unidirectional clutch device, comprising a key (60) and a sleeve (58) incorporating the finger (52), said sleeve being slidably mounted on the plunger and capable, when the control rod is actuated at a given speed, of being locked in relation to the moving piston, independently of the control rod, characterised in that the sleeve (58) comprises a first and a second adjustable parts (104, 106) which can be axially plastically deformed for an adjustment of the servomotor prior to its assembly.

Abstract: A hydraulic pressure brake device includes a master cylinder, a brake operating member, a master piston, a booster, a first auxiliary piston, a pressure transmitting chamber, a valve device, and a second auxiliary piston. The hydraulic pressure brake device further includes an output member and a rod. The output member is provided in the booster for transmitting the boosting power generated by the booster to the first auxiliary piston when the movement of the master piston is assisted by the booster. The rod is provided in the second auxiliary piston for transmitting the operating force applied to the brake operating member to the valve device and for opening the valve device when the movement of the master piston is not assisted by the booster.

Abstract: The present invention relates to a vehicle brake system with a pneumatic brake booster (1) which includes an input member (7) being actuated by a vehicle operator and an output member (push rod) (14) as well as a control housing that carries a movable wall (2) and accommodates a reaction plate (6) at least in part, wherein there is further provision of means for detecting the point of maximum boosting of the pneumatic brake booster that can be used for the actuation of another brake force boosting device.

Abstract: A vacuum booster which moderates a retraction speed of a valve seat member to restrain a contact noise between a key member retracting in a unitary manner with the valve seat member and a flange surface of a plunger. The vacuum booster includes a noise restriction device.

Abstract: The present invention is directed to a vehicle motion control system, which includes wheel brake cylinders, an automatic hydraulic pressure generating apparatus for generating a hydraulic braking pressure irrespective of operation of a brake pedal, a hydraulic pressure control valve device disposed between the pressure generating apparatus and the wheel brake cylinders to control the hydraulic braking pressure in each wheel brake cylinder, and a controller for controlling the pressure generating apparatus and the valve device in response to conditions of vehicle motion, and performing an automatically pressurizing control to the wheel brake cylinders at least when a brake pedal is not depressed, to perform a vehicle motion control.

Abstract: A hydraulic brake device includes a cylinder, a larger diameter piston movable within the cylinder in response to operation of a brake booster power piston, a smaller diameter piston engaged with and movable relative to the larger diameter piston in response to movement of a brake operation member, a floating piston engaged with the smaller diameter piston and movable relative thereto, a first pressure chamber defined by the larger diameter piston and the smaller diameter piston, a second pressure chamber defined by the cylinder and the floating piston and hydraulically connected to a wheel brake, and a relief chamber defined by the cylinder and the larger diameter piston. A switching device is disposed between the larger and smaller diameter pistons for normally interrupting fluid communication between the first pressure chamber and the relief chamber and for establishing fluid communication therebetween when the larger and smaller diameter pistons are relatively moved.

Abstract: A method and system for ensuring reliable operation of a brake booster system for a vehicle braking system in which a pressure value prevailing in the brake pressure reservoir of the brake booster system is sensed by a pressure sensor. An error occurring in the brake booster system is detected by evaluating the sensed pressure value prevailing in the brake pressure reservoir as a function of the actuation of the brake actuating mechanism. The brake booster system includes a diagnostic circuit that is connected to the pressure sensor and to the brake actuating mechanism.

Abstract: Braking device comprising a master cylinder (2), a primary piston (3), a manual control member (4), a booster (6) coupled to the manual control member (4) and an emergency assist valve (VA) comprising a reaction piston (17) through which there passes a ratio control (T) having a head (26a) situated in a chamber (35) lying between the reaction piston (17) and a bushing (36) located further forward in a bore (18) in the primary piston, this bushing (36) having a bore (37) in which there can slide a rapid piston (38), the rear end (45) of which forms, with the head (26a) of the ratio control, a valve (C) capable of closing the inlet to a passage (39) in the rapid piston against the action of a spring (41). The device comprises a means (26, 27, 30) for preventing a sharp retreat of the reaction piston (17) when the manual control member (4) is released after slow braking.

Abstract: A servobrake having a rigid jacket defined by a first shell joined to a second shell by through tie-bars to create variable volume front and rear chambers. The front chamber is permanently connected to a first pressure source whereas the rear chamber is selectively connected to the first pressure source and a second pressure source. The servobrake including a pressure sensor for the measurement of the pressure inside of the front and rear chambers. The pressure sensor is characterized by being attached to a front end of the through-tie bar whereas the tie-bar is characterized by a hollowed-out body with a hollow inner needle sealingly retained therein. The hollow inner needle defines a first chamber while a second chamber is defined by a space between the inner hollow needle and the hollowed-out body. The hollowed-out body has first ports therein for connecting the rear chamber with the first chamber through which pressure present in the rear chamber is transmitted to the pressure sensor.

Abstract: An actuating device for the brake system of a motor vehicle includes a pedal block (1) with a brake pedal (10) fixed thereon pivotably, with a brake booster (2) with a housing having a housing bottom part (6) and a housing bell (5) and with a master cylinder assembly unit (3) connected thereto for admitting hydraulic power into the individual wheel brakes of the motor vehicle. The pedal block (1) and the housing bottom part (6) are molded in one piece from a plastic. The said housing bell (5) and the master cylinder assembly unit (3) with reservoir (4) with a reservoir bottom (4a) and a piston unit (14) is molded as a one-piece plastic part. A hydraulic tube (15) jacketed by the plastic part for receiving the said individual brake pistons (17) is arranged within the piston unit (14).

Abstract: A pneumatic servobrake having a detector (13) for the measurement of the pressure in a front chamber (1). The detector (13) has a baseplate (14) that is situated opposite an opening (25) in a wall (26) of the front chamber (1). A yoke-forming cage (38) that is placed over the opening (25) has an opening (40) that is traversed by a pressure sampling tube (16). The tube has a collar (41) that is retained between the cage (38) and the baseplate (14). An adapter (23) connected to the wall (26) urges the tube (16) against the cage (38) to allow for both a sideways motion (20) and a tilting motion (21). The lower part (31) of the tube (16) is fitted with an O ring (33) to establish a sealed pneumatic connection between the tube (16) and baseplate (14) such that a first sensor (15) is isolated from a second sensor (48) in a measurement of pressure in the first chamber (1).

Abstract: A vehicle brake apparatus comprises brake operation detecting device for detecting an operation of a brake operating member, pressure detecting device for detecting a pressure supplied to a recirculating type hydraulic pressure modulator, and an electric motor control device. The recirculating type hydraulic pressure is disposed in a hydraulic pressure conduit between a master cylinder and a wheel brake cylinder. The electric motor control device drives an electric motor for activating a recirculating pump in response to the brake operation detected by the brake operation detecting device and the pressure detected by the pressure detecting means so that the pressure in the wheel brake cylinder is modulated.

Abstract: A vehicle motion control device which includes a wheel cylinder equipped on a vehicle wheel; an automatic hydraulic pressure generator generating a brake hydraulic pressure irrespective of the operation of a brake pedal by using an intake vacuum pressure of an engine of a vehicle; a hydraulic pressure control valve disposed between the wheel cylinder and the automatic hydraulic pressure generator; a throttle opening amount automatic adjusting device for adjusting automatically the opening amount of a throttle valve of the engine irrespective of the operation of an accelerator pedal of the vehicle; control, device for controlling the automatic hydraulic pressure generator and the hydraulic pressure control valve in accordance with a running condition of the vehicle and for performing an automatic pressure increase control to the wheel cylinder at least non-operating condition of the brake pedal, the control means for controlling the throttle opening amount automatic adjusting device in accordance with the runn

Abstract: The invention relates to a brake system including a brake booster. A pneumatic pressure operated brake booster VBB or a liquid pressure operated brake booster includes a valve mechanism which is urged by a force of depression applied to a brake pedal BP to switch a flow path to cause the brake booster to develop an output which depends on the magnitude of the force of depression. A solenoid SOL urges the valve mechanism in the same direction as or in the opposite direction from the force of depression. A controller ECU is responsive to a braking effort increase/decrease demand signal to increase or decrease the urging force which is applied by the solenoid to the valve mechanism, thus increasing or decreasing the output from the brake booster. An output from the brake booster can be freely controlled independently from the force of depression applied to the brake pedal in response to a braking effort increase/decrease demand.

Abstract: A boosted braking device for a motor vehicle having a master cylinder (M) and a pneumatic booster (S). The booster (S) has a rigid casting (10) divided by a mobile partition (12) into at least a front chamber (14) and a rear chamber (16). A three-way valve (18) carried by the mobile partition (12) is actuated by a control rod (20) to control the pressure in the rear chamber (16) for operating the master cylinder (M). The casing (10) includes a front shell (24) and a rear shell (26) each of which comprises a radial shoulder (28,30) and being secured together by hooping (40) interconnecting with the shoulders (28,30) of the front shell (24) and rear shell (26). The hooping (40) comprises first (40A) and second (40B) part hoops. The first (40A) and second (40B) part hoops are joined together by at least one locking element (50) which is rendered non-functional when the master cylinder (M) is subjected to substantial stress as a result of a frontal or oblique impact of the vehicle.

Abstract: A tandem pneumatic booster includes a front shell having a relatively long cylindrical portion and a rear shell having a relatively short cylindrical portion. The cylindrical portions of the front and rear shells are joined together to form a shell body. An opening edge of a cylindrical portion of a center shell is disposed in the joint between the front and rear shells, together with an outer peripheral bead of a diaphragm of a rear power piston. The cylindrical portion of each of the front, rear and center shells has a frusto-conical shape gradually increasing in diameter toward the opening edge thereof. Thus, when front shells, rear shells and center shells are stacked on one another, respectively, as constituent parts before assembly, the depth of fitting between each pair of adjacent shell elements is increased sufficiently to maintain the stacked conditions of the shell elements stably.

Abstract: This braking force amplifier with dual amplification ratios includes a thrust assembly (71) comprising a reaction rod (82) connected to the master-cylinder of the corresponding brakes and mounted to be axially displaceable under the control of a plunger (22) between a first braking state corresponding to a first ratio of amplification of the braking force, and a second braking state corresponding to a second ratio of amplification of the braking force, and a deformable reaction disc (96) interposed between a piston (70) and the plunger on the one hand, and the reaction rod on the other. The thrust assembly includes means (104) for absorbing the deformations of the reaction disc, the said deformations contributing to determining the braking force for which passage between the first and the second braking states takes place.

Abstract: This invention mainly relates to a receiving housing for a reaction disk and to a pneumatic servomotor for an assisted braking, including such housing fitted with its reaction disk.

Abstract: A system or method for compensating for low vacuum levels in a brake-by-wire system includes continually monitoring the level of vacuum in a vacuum booster. The state or condition of the vacuum source is also monitored to determine whether it is on or off. When the vacuum source is off, the level of vacuum is measured to determine whether it is at or below a critical level. If the level of vacuum is critically low, the vacuum source is turned on. If the vacuum level is not critically low, the hydraulic boost gain is modified in order to provide more braking pressure in response to brake force exerted at the brake pedal.

Abstract: The solenoid current increases at low temperatures and decreases at high temperatures because the modulus of elasticity of an elastically deformable valve body and the slide resistance of an elastically deformable seal member vary with temperatures. Therefore the solenoid current for opening the valve mechanism from a closed position is required to be changed with low and high temperatures. To supply the solenoid current necessary for opening the valve mechanism without directly measuring the temperature, the solenoid current (the boost starting current leaning value) indicated when the pressure varies with the opening of the valve mechanism is recorded at the time of pressure-increasing, and thereafter when the valve mechanism is opened again after the closing of the valve mechanism, the solenoid current computed on the basis of the pressure-increase starting current learning value thus recorded is supplied.

Abstract: There is disclosed a pneumatic booster having a vacuum chamber connected to an intake pipe of an engine. An air outlet of an ejector is connected to the intake pipe through a vacuum control valve, and an air inlet of the ejector is connected to an air cleaner. A vacuum pick-up port of the ejector is connected to the vacuum chamber of a booster body. The vacuum control valve comprises a control chamber and a control piston, and the negative pressure in the booster is introduced into the control chamber and acts on the control piston. When the negative pressure in the booster is insufficient, the control piston acts to open the control valve and a negative pressure is supplied from the ejector to the vacuum chamber. When the negative pressure in the booster is sufficiently high, the control piston acts to close the control valve and stops the operation of the ejector, thus reducing an effect of the ejector with respect to an air/fuel ratio of the engine.

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: A hydraulic pressure control device is provided in which a proportional pressure control valve is actuated by operating the brake pedal to adjust the hydraulic pressure supplied from a pressure source to the wheel brakes to a value corresponding to the pedal operating amount. Also, a brake device for a vehicle using it is provided. The proportional pressure control valve is integrated with a hydraulic pressure generator to transmit the input from the brake pedal to a spool valve in the control valve through a first piston, first spring, second piston and second spring of the hydraulic pressure generator. If the pressure source or the wheel brakes in a first line fail, after the second piston has made a full stroke, brake fluid in a fluid chamber is pressurized, so that the hydraulic pressure generated is supplied to wheel brakes in a second line through a copy valve which is open.

Abstract: The invention provides a pneumatic servomotor for an assisted braking of a motor vehicle, of the type comprising a unidirectional clutch device (56), which includes a coaxial sleeve (58), sliding on a plunger (46), and a substantially ring-shaped key (60), arranged with a given clearance around the sleeve (58) and capable of being driven by a moving piston (22) when an input force is applied at a determined speed onto a control rod (38) integral with the plunger (46), so as to rock and lock the sleeve in an axial position, in which it locks the piston (22), independently of the control rod (38), characterised in that the unidirectional clutch device (56) comprises at least one locking transverse face (76) for the sleeve, said face being axially directed rearwards so as to form a stop for a peg (78) provided on the key (60) and extending radially towards the sleeve (58), for an axial indexing of the end locking position of the sleeve (58).