Abstract: A switching reservoir which reserves brake fluid for reducing a pressure to a wheel cylinder is connected to a pressure decrease control valve and an intake port of a pump through a reservoir port, and connected to a M/C through a connection port. There are a ball valve and a rod below the ball valve inside the connection port. The rod moves up and down the ball valve integrally with a piston of the reservoir chamber. When an amount of the brake fluid in the reservoir chamber becomes less than a predetermined amount, the rod moves upward to cause the ball valve separates from a valve seat and is changed to be in an open sate, allowing the brake fluid to flow in from the M/C. Accordingly, the pump is always capable of sucking up the fluid, thereby preventing sharp increase of the rotational speed of the motor due to a sharp decrease in the pump load caused by an empty reservoir chamber and enabling driving of the motor with a duty control. Therefore, low noise and low pulse pressure can be achieved.

Abstract: The present invention provides a proportional microvalve having a first, second and third layer, and having high aspect ratio geometries. The first layer defines a cavity with inlet and outlet ports. The second layer, doped to have a low resistivity and bonded between the first and third layers, defines a cavity having a flow area to permit fluid flow between the inlet and outlet ports. The second layer further defines an actuatable displaceable member, and one or more thermal actuators for actuating the displaceable member to a position between and including an open and a closed position to permit or occlude fluid flow. The third layer provides one wall of the cavity and provides electrical contacts for electrically heating the thermally expandable actuators. The thermal actuators and the displaceable member have high aspect ratios and are formed by deep reactive ion etching such that they are displaceable in the plane of the second layer while being very stiff out of the plane.

Abstract: A brake control system includes an ECU having an estimate part which is so constructed as to: totalize an influent amount of fluid in a brake actuator in accordance with an output time of a valve opening drive signal of a control signal and a supply amount per unit time of fluid in a pressure control valve; estimate an amount of fluid in the brake actuator in accordance with the influent amount as totalized; estimate a value of the fluid pressure within the brake actuator in accordance with the amount of fluid as estimated; and carry out correction for obtaining a supply amount of fluid in the brake actuator when a time of retaining operation performed by the control signal is smaller than a predetermined value, correction being performed by adding a correction value corresponding to the time to the output time of the valve opening drive signal of the control signal.

Abstract: In a hydraulic vehicle braking systems operable via hydraulic external energy from a pump or, in the event the pump malfunctions, via hydraulic energy made available using a master brake cylinder via muscle-powered energy, provision is made for safe braking via muscle-powered energy such that at least one cylinder-piston configuration isolates at least two wheel brakes from the hydraulic pressure medium that is able to be pumped by the pump. The hydraulic vehicle-braking system incorporates wheel brakes of one axle that is isolated from a hydraulic pump in terms of pressure medium by a cylinder-piston configuration, which wheel brakes are supplied with pressure medium by one master cylinder chamber of a master brake cylinder. The other master brake cylinder chamber is allocated to the two other wheel brakes of the other vehicle axle, so that given bubble-free pressure medium downstream from the pump, the wheel brakes of both vehicle axles make a contribution to vehicle deceleration.

Abstract: A brake actuator element used in a hydraulic brake system and exposed to brake fluid. It includes a piston formed with a not-through hole, and a pin pressed into the piston. A channel is defined between the inner wall of the not-through hole and the outer periphery of the pin. Through this passage, the gap defined between the bottom of the pin and the bottom of the not-through hole when the pin is pressed into the not-through hole is always kept in communication with the outer air. Thus, any air remaining in the gap smothly escapes through the channel when the pin is pressed into the not-through hole.

Abstract: An accumulator (1) capable of suppressing a hydraulic pressure vibrating noise in the range of a sealed gas pressure or below and being reduced in size, wherein an operating member (5) having a bellows (6) is disposed in a housing (2) to partition the inside of the housing (2) into a pressure sealed chamber (8) and a pressure inflow chamber (9) and a fluid inlet (15) for leading pressure fluid from a system side to the pressure inflow chamber (9) is formed in the end wall part (3a) of the housing (2), a chamber forming member (17) is fixed to the inside of the housing (2), and a chamber (18) and a choke (19) are provided between the chamber forming member (17) and the end will part (3a) of the housing (2).

Abstract: A vehicle electro-hydraulic braking system having a fluid pressure accumulator of the pre-charged diaphragm type which is used to store fluid under pressure, charged by means of a fluid pump or compressor driven either by an electric motor or directly from the vehicle engine for supply to a valve system which is adapted to supply the brake or brakes of the vehicle with fluid pressure in accordance with the level of the driver's braking demand, the control of the accumulator pressure being arranged to lie within a fixed control range, with a cut-in pressure defining the lower limiting pressure of the control range and a cut-out pressure defining the upper limiting pressure of the control range, and there being a warning pressure range defined between a warning pressure level and the cut-in pressure, wherein at least one of the warning, cut-in and cut-out pressure levels is arranged to be controlled in dependence upon temperature.

Abstract: An actuating unit for a wheel brake of a motor vehicle has a hydraulic pump drivable with variable speed by an electric motor, as well as an element, adjusting the return flow of pressurized media to the pump, which is arranged between the delivery side and the intake side of the pump. Furthermore, a cylinder-piston unit is provided, having a piston with identical surfaces on both sides, as well as a cylinder having cylinder chambers arranged on both sides of the piston. In order to press a brake lining against a friction element connected to a vehicle wheel, the pump is connected on the intake side to the cylinder chamber on the brake-lining side, and on the delivery side to the cylinder chamber facing away from the brake lining. The actuating unit is assigned a control device by which an electric brake request signal is able to be processed, and the electric motor and the element are controllable.

Abstract: A brake control system includes an ECU constructed to carry out pressure-increase assist control for restraining the opening of an OUT-side gate valve and opening inlet valves during a predetermined time when active brake control is switched from the state that it is effective for only one wheel cylinder to the state that it is effective for only another wheel cylinder.

Abstract: An auxiliary vehicle hydraulic pressure source device includes a hydraulic pressure pump pressurizing and discharging fluid, an accumulator accumulating fluid pressurized and discharged by the hydraulic pressure pump, a hydraulic pressure detector continuously detecting the accumulator hydraulic pressure, and a controller controlling operation of the hydraulic pressure pump based on a comparison of the detection result of the hydraulic pressure detector with a predetermined target pressure.

Abstract: A controlled brake apparatus and method of operating a brake apparatus utilize a pre-charge circuit connected directly between the fluid reservoir of a master cylinder of the apparatus and the inlet of a controlled braking pump, to thereby direct pre-charge flow and pressure to the controlled braking pump inlet in a parallel circuit relationship to a primary hydraulic circuit, rather than in a series flow arrangement through the primary hydraulic circuit as was the case in prior brake systems. The pre-charge circuit includes an integral back-flow check valve, and an accumulator.

Abstract: A control method of a hydraulic pressure source-driven type vehicle hydraulic pressure brake system in which no irritating noises or vibrations are produced during stoppage of the vehicle and which does not consume electric power in waste. When the vehicle stops and the surroundings become quiet, by detecting stoppage of the vehicle by a sensor for detecting the rotation of a wheel, stopping a motor for a pump for producing brake hydraulic pressure, and opening a solenoid valve in a master cylinder passage bringing the master cylinder and the wheel cylinder into communication with each other, it is possible to prevent noises or vibrations from the motor and wasteful consumption of electric power.

Abstract: The present invention relates to an improved hydraulic brake system for controlled and comfortable braking operations which includes a hydraulic pump for build-up of a hydraulic pressure that effects braking and a valve assembly by way of which the hydraulic pressure can be reduced, the hydraulic system being in particular characterized in that the valve assembly is an analog valve, and in that the analog valve and the hydraulic pump are adapted to be actuated by a control device in such a manner that the brake pressure for comfort braking can be increased or decreased in an essentially continuously variable manner.

Abstract: An actuating unit (1) for a wheel brake (2) of a motor vehicle has a hydraulic pump (12), which can be driven at variable speeds by an electric motor (11) and supplies pressure fluid from a storage tank (22), and has an element (24), which adjusts a return flow of pressure fluid to the pump (12) and is disposed between the pressure side (13) and the suction side (16) of the pump (12). In addition, a cylinder-piston unit (3) is provided, which is for pressing a brake lining (7) against a friction element (8) connected to a vehicle wheel. For purposes of controlling the brake pressure as a function of wheel slip, a pressure increase valve (18) and a pressure decrease valve (21) are disposed between the pump (12) and the cylinder-piston unit (3). In addition, a control unit (29) is provided, which can process electrical brake request signals and slip signals and can control the electric motor (11), the element (24), and the valves (18, 21).

Abstract: A braking system including (a) a hydraulically operated brake cylinder for operating a brake, (b) a master cylinder operable according to an operation of a manually operable brake operating member, to pressurize a working fluid, (c) a master-cylinder cut-off valve connected to the master cylinder, (d) a high-pressure source such as a power-operated pressure-control cylinder disposed between the master-cylinder cut-off valve and the brake cylinder and operable according to the operation of the brake operating member, to pressurize the fluid, the high-pressure source including a power-operated drive device and a pressure-control cylinder having a control piston which is operable by the power-operated drive device and which partially defines on respective front and rear sides thereof a front control-pressure chamber connected to the brake cylinder, and a rear pressure chamber which is held in communication with the master cylinder, and (e) a braking-pressure control device (200) operable to control the power-ope

Abstract: A vehicle braking system of the type in which a stored volume of fluid is used to apply the wheel brakes of the vehicle under the control of an electronic unit, the stored volume being held in an accumulator arranged to be replenished by pumping additional working fluid using a pump driven by an electric motor. The speed of the pump electric motor is arranged to be controlled in dependence upon whether or not any vehicle dynamic intervention, such as ABS, TC and VSC, is active. If it is deduced that one or more vehicle dynamic functions is active, then the pump is arranged to be run at high/full, and relatively noisy, speed, but if it is concluded that only base braking is being applied with no vehicle dynamic function being active, then the pump is arranged to be operated at a relative slower and hence quieter speed.

Abstract: A brake control system includes an ECU constructed to carry out pressure-increase assist control for restraining the opening of an OUT-side gate valve and opening inlet valves during a predetermined time when active brake control is switched from the state that it is effective for only one wheel cylinder to the state that it is effective for only another wheel cylinder.

Abstract: In a pump equipment having one or more rotary pumps for hydraulic circuit, the intake port is communicated with the shaft hole for inserting the drive shaft and fluid flows through the shaft hole to a fluid groove provided in inner surfaces of the pump room for the purpose of lubrication. To prevent fluid leakage to outside, first and second oil seals are disposed for filling the clearance between the drive shaft and the shaft hole and, preferably, a communicating conduit is provided between the first and second oil seals to transmit the fluid leaked through the first oil seal to a low pressure fluid conduit of the hydraulic circuit. In particular, in the pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other, the reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports.

Abstract: There is provided a pedal apparatus for vehicles, which comprises a pedal reaction-force addition means 4 for adding a reaction force to a pedal 1 of a vehicle, a pedal force detection means 2 for detecting a force added to the pedal 1, a pedal reaction-force control means 3 for adjusting the output of the pedal reaction-force addition means 4. During the running of the vehicle, the pedal reaction-force control means 3 performs the adjustment of a reaction force of the pedal on the basis of the driving environment of the vehicle and the driver's intention and judgement in pedal operation in the driving environment, whereby it is ensured that when the driver has no intention of operating the pedal, the driver can sufficiently place his or her foot on the pedal and that when he driver has any intention of operating the pedal, the driver can realize a smooth pedal operation.

Abstract: A method and device for driving an arrangement, in a vehicle, that delivers a pressurized medium in a brake system, the pressurized medium being delivered in at least one brake circuit of the brake system, and a pressurized medium volume available in the brake circuit being dependent upon the driving of the arrangement delivering the pressurized medium. In this context, the arrangement delivering the pressurized medium is driven as a function of the vehicle speed so as to effect a correlation between the vehicle speed and the pressurized medium volume available in the brake circuit. This means, in particular, that the vehicle speed and the pressurized medium volume available in the brake circuit are linked in such a way that, with rising vehicle speed, the available volume of pressurized medium in the brake circuit is increased, and/or with falling vehicle speed, the available volume of pressurized medium in the brake circuit is decreased.

Abstract: Disclosed is a microvalve suitable for use in high pressure applications such as refriigeration. The microvalve has a displaceable member that slides across an inlet port, thereby creating an orifice. A pressure-equalizing contour is positioned beneath the displaceable member and is in fluid contact with the inlet port. The pressure on the displaceable member from the inlet port is equalized by the pressure from the pressure-equalizing contour. Consequently, the microvalve can be configured with its inlet port and outlet port on opposite sides of the microvalve. Pressures in the x and y direction are also equalized because of recesses that permit fluid from the inlet to contact all faces of the displaceable member.

Abstract: The present invention relates to a method and device for driving a brake system pump motor, which has the advantage of simultaneously allowing prioritized, individual braking strategies, using the present invention as a subsystem for intelligently driving the pump motor. The invention provides the additional advantage of reducing pump motor current requirements, allowing the use of a reduced size of pump motor. The invention provides for a predetermined period of full-on voltage at the initiation of a braking request, subsequent periods of variable pump motor voltage on-time, depending on pulse width modulation of a drive motor signal based on a comparison between the motor voltage and a threshold voltage, and subsequent periods of full-on voltage for a predetermined period based on a comparison between the motor voltage and a safety threshold voltage. The invention also provides for minimum on-time per clock cycle for safe braking operations.

Abstract: A method of brake pressure adjustment in a vehicle brake system equipped with an electric hydraulic pump comprises the following steps: detecting a prevailing brake pressure or determining a nominal pressure, and actuating the pump by degrees according to the detected brake pressure or the nominal pressure. In a method of opening an inlet valve of a hydraulic vehicle brake system, a pressure rise on the inlet side of the inlet valve is generated when the difference between the outlet-side and the inlet-side pressure on the inlet valve exceeds a positive threshold value.

Abstract: Improving operating feelings and energy saving are aimed for a brake system of the type in which a predetermined differential pressure is produced between a master cylinder and wheel cylinders by a hydraulic pressure limit/changeover device during regenerative braking, and at the end of regenerative braking, the differential pressure is cancelled by increasing the pressure in the wheel cylinders with fluid sucked up from a reservoir for pressure increase by an electric pump. A reservoir for pressure increase, which is also used as a stroke simulator, is provided on the master cylinder side of the hydraulic pressure limit/changeover device, an on-off valve and a check valve are provided parallel to each other on the inlet side of the reservoir for pressure increase.

Abstract: A brake system includes a brake adapted to receive a brake fluid. The brake is in fluid communication with a brake fluid conduit. The brake system includes a pressure accumulator adapted to store the brake fluid under pressure. The pressure accumulator is in fluid communication with a supply conduit. The brake system includes a pump in fluid communication with the brake fluid conduit and the supply conduit. The brake system includes a bypass valve in fluid communication with the brake fluid conduit and the supply conduit. The bypass valve is positioned to allow the brake fluid to flow from the pressure accumulator to the brake without flowing through the pump.

Abstract: A vehicle hydraulic brake apparatus includes a brake member, a master cylinder generating a brake hydraulic pressure by increasing the pressure of brake fluid in a reservoir, a master piston moved forward in response to operation of the brake member, a closed chamber defined behind the master piston, a power piston disposed behind the master piston, and a power chamber defined behind the power piston. An auxiliary hydraulic pressure source generates power hydraulic pressure and a pressure regulating device connects the auxiliary hydraulic pressure source with the reservoir. The power hydraulic pressure is regulated to a predetermined hydraulic pressure and is fed to the power chamber. A normally-open type valve connects the closed chamber and the power chamber, and is closable upon operation of the brake member. The closed chamber is connected to the reservoir via the normally-open type valve, the power chamber and the pressure regulating device.

Abstract: A hydraulic system for actuating at least two operating systems of a motor vehicle has a first hydraulic medium reservoir for storing a hydraulic medium. A distribution valve is connected to the first hydraulic medium reservoir and to the operating systems of the motor vehicle. A control unit is connected to the distribution valve which is configured to distribute the hydraulic medium from the first hydraulic medium reservoir to the operating systems of the motor vehicle and to control flow of the hydraulic medium to the operating systems of the motor vehicle such that one of the operating systems has priority with regard to supply of the hydraulic medium. A first one of the operating systems is a brake device having a brake power assist unit, a brake valve, and a master brake cylinder. The brake power assist unit is connected via the brake valve to the control unit.

Abstract: Automotive hydraulic pressure brake system with a stroke simulator is proposed which while the electric control system is functioning properly, the supply of hydraulic pressure from a master cylinder is cut off and hydraulic pressure is generated by a power pump. This improves response upon rapid pressure increase while minimizing the increase of pedal stroke and the worsening of the pedal feeling. A bypass is provided to communicate the master cylinder to the wheel cylinders while bypassing an on-off valve to be closed during ordinary braking. A shut-off valve is provided in the bypass and a check valve or a relief valve for allowing only a fluid flow from the master cylinder toward the wheel brake cylinders is provided.

Abstract: A vehicle braking system of the type in which a stored volume of fluid is used to apply the wheel brakes of the vehicle under the control of an electronic unit, the stored volume being held in an accumulator arranged to be replenished by pumping additional working fluid using a pump driven by an electric motor. The speed of the pump electric motor is arranged to be controlled in dependence upon whether or not any vehicle dynamic intervention, such as ABS, TC and VSC, is active. If it is deduced that one or more vehicle dynamic functions is active, then the pump is arranged to be run at high/full, and relatively noisy, speed, but if it is concluded that only base braking is being applied with no vehicle dynamic function being active, then the pump is arranged to be operated at a relative slower and hence quieter speed.

Abstract: A brake system includes first brake assist means arranged in a first brake circuit to increase a first wheel cylinder pressure to a level higher than a master cylinder pressure. The brake system further includes second brake assist means arranged in a second brake circuit to increase a second wheel cylinder pressure to a level higher than the master cylinder pressure. The second brake assist means includes a brake regulator mechanism that uses the increased first wheel cylinder pressure as a pilot pressure and adjusts the increased second wheel cylinder pressure to a pressure falling within a predetermined range from the increased first wheel cylinder pressure when the first brake assist means is activated.

Abstract: A hydraulic wheel brake system including a plurality of brakes and a hydraulic brake controller. The brakes includes wheel cylinders corresponding respectively to each wheel. The hydraulic brake controller includes a pump device, and a pump and valve controller. At least one pump included in the pump device is reversible. By controlling the pump and valve controller the pump increases brake fluid pressure in the brake during braking and the brake fluid pressure is reduced through the pump when it is required to be reduced. The hydraulic brake controller has a normal-open solenoid valve between a reservoir and the brake. The normal-open solenoid valve allows the brake fluid to flow when an electric current is not supplied. The hydraulic brake controller has also a normal-close solenoid valve between the reservoir and the brake. The normal-close solenoid valve prevents the brake fluid from flowing when an electric current is not supplied.

Abstract: A method and a device for compensating for an accumulator pressure in an electrohydraulic braking system of a motor vehicle, in which a valve arrangement controls an input of a hydraulic fluid from a pressure accumulator into wheel brake cylinders, the hydraulic fluid being deliverable by a pump into the pressure accumulator, in which a variable is defined that corresponds to a driving situation and/or a driver's command and that represents a setpoint wheel pressure with which at least one wheel brake cylinder is chargeable to achieve an optimal braking action, the variable is compared to another variable representing an accumulator pressure in the pressure accumulator to provide a comparison result, and the accumulator pressure is increased in response to the comparison result falling below a predefinable minimal difference between the variable representing the setpoint wheel pressure and the another variable representing the accumulator pressure.

Abstract: In a brake system of a vehicle in which a pair of wheel cylinders are supplied with a fluid pressure by a fluid circuit having a pair of inlet control valves for selectively connecting the pair of wheel cylinders respectively to an outlet port of a motor-driven pump and a pair of outlet control valves for selectively connecting the pair of wheel cylinders respectively to a fluid reservoir, a brake control device controls the motor driving of the pump and opening/closing of the inlet and outlet control valves, such that a controlled fluid pressure is supplied to the pair of wheel cylinders at least temporarily with the pair of inlet control valves substantially fully opened, while the pair of outlet control valves substantially closed, wherein it is judged if there is a difference between output signals of a pair of wheel cylinder pressure sensors beyond a predetermined threshold value, thereby judging the pair of wheel cylinder pressure sensors to be both operating normally when the difference is not larger t

Abstract: A hydraulic brake system with anti-lock control comprises a main cylinder connected to a reservoir, wheel brakes connected to the main cylinder by way of brake lines, and a recirculating pump, a suction side of which is connected to the wheel brakes by way of a first suction line. By way of a second suction line, the pump is connected to a pressure source. To control the pressure medium supply from a precharging device or other pressure source to the suction side of the recirculating pump as a function of the pressure in the second suction line, a hydraulically actuated valve is used. The inlet of the valve is connected to the precharging device via the pressure source, the outlet of the valve is connected to the suction side of the recirculating pump. The output pressure of the valve acts in a valve closing direction such that the valve closes once a pressure on the suction side of the recirculating pump exceeds a certain value.

Abstract: An activation signal of a pump of a braking system is created as a function of a pressure gradient, preferably from a pressure accumulator. In this context, the switched-on time of a pulse-width modulated signal within an activation clock cycle is varied, taking into consideration the accumulator pressure gradient, in order to activate the pump. This is done by addressing a switching arrangement by way of a control unit. Activation as a function of the pressure gradient can be accomplished alternatively to or in combination with activation as a function of the generator voltage of the pump motor.

Abstract: A solenoid valve useful in a slip-controlled hydraulic brake system of a motor vehicle, and which has a seat valve disposed between a pressure fluid inlet and a pressure fluid outlet and in the bypass to this seat valve, has a check valve with a hollow conical valve seat and a closing body, which has a section that is embodied as complementary to the hollow conical valve seat. A rubber-elastic sealing ring is accommodated with the greater portion of its cross section in the circumference of the section and in the closed position of the check valve, this sealing ring can compensate for dimensional deviations of the valve seat at low pressures.

Abstract: A fluid compensator is provided in a hydraulic control unit of vehicular brake system. The fluid compensator permits additional displacement of a master cylinder piston during anti-lock braking events only by storing fluid in the hydraulic control unit. The additional displacement moves a seal mounted on the master cylinder piston away from a compensator port orifice, thereby preventing repeated “nibbling” of the seal which can cause premature seal failure.

Abstract: An electromagnetic valve has a plunger as an armature of an electromagnetic actuator and a ball as a movable valve member. The plunger and the ball are separated to permit the ball to move freely in response to a pressure difference between an inlet and an outlet when the coil attracts the plunger. If the plunger undesirably moves by a pressure difference between both ends of the plunger, the ball can keep a closing condition during a suction pressure that is higher than a pressure in the inlet. Therefore, an undesired communication between a master reservoir and a pump is avoided.

Abstract: A brake control device has a master cylinder, wheel cylinder, and a solenoid valve disposed in a conduit between the master cylinder and the wheel cylinder. When a brake pedal happens to be returned at sudden braking, at an idle stop or at vehicle stop on a sloping road, the solenoid valve is controlled at a duty rate based on a difference between a peak value of master cylinder and an actual value of master cylinder reducing so that wheel cylinder pressure is held to a value higher than master cylinder pressure.

Abstract: The present invention relates to an arrangement for actuating an automotive vehicle brake system of the type ‘brake-by-wire’, which comprises an actuating pedal and a travel simulator which cooperates with the brake pedal and whose simulator piston is in a force-transmitting connection with the actuating pedal and is preloaded by a spring, and which includes means of attenuating the movement of the simulator piston as a function of the actuating pedal travel. To achieve an effective attenuation, according to the present invention, the simulator piston (11) delimits a hydraulic chamber (12) which is connected to a second hydraulic chamber (4 or 14, respectively) by way of at least one variable flow resistance (16,17,18,19,20).

Abstract: A braking system including a brake cylinder, a first hydraulic pressure source having a first pump device for pressurizing a working fluid, a second hydraulic pressure source operable in response to an operation of a brake operating member, to pressurize the fluid to a pressure higher than a value corresponding to an operating force of the brake operating member, and a brake-cylinder-pressure control device operable when the brake cylinder is disconnected from the second hydraulic pressure source, to control the pressure of the fluid pressurized by the first hydraulic pressure source, such that the fluid pressure in the brake cylinder is controlled to a value determined on the basis of the operating force, and wherein an emergency communication device is operated when at least one of the brake-cylinder-pressure control device and the first pump device fails to normally function, to hold the brake cylinder in communication with the second hydraulic pressure source.

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: The present invention is directed to a brake control system for a vehicle, which includes a cut-off valve for opening or closing a main passage, which communicates a master cylinder with a wheel brake cylinder, and a pump for discharging the pressurized brake fluid to the wheel brake cylinder, with an outlet of the pump connected to a position between the cut-off valve and the wheel brake cylinder. An inlet valve is provided for opening or closing an auxiliary passage which communicates an inlet of the pump with the master cylinder. And, a controller is adapted to place the cut-off valve in a closed position thereof, place the inlet valve in an open position thereof, and actuate the pump to supply the pressurized brake fluid discharged from the pump into the wheel brake cylinder, when a brake-assist control is to be performed.

Abstract: In a pump equipment having one or more rotary pumps for a hydraulic circuit, the intake port is communicated with the shaft hole for inserting the drive shaft and fluid flows through the shaft hole to a fluid groove provided in inner surfaces of the pump room for the purpose of lubrication. To prevent fluid leakage to the outside, first and second oil seals are disposed for filling the clearance between the drive shaft and the shaft hole and, preferably, a communicating conduit is provided between the first and second oil seals to transmit the fluid leaked through the first oil seal to a low pressure fluid conduit of the hydraulic circuit. In particular, in the pump equipment having plural rotary pumps, the respective discharge ports of the rotary pumps are located at the points which are nearly symmetrical with respect to the center axis of the drive shaft to counterbalance each other, the reaction forces against the drive shaft to be produced by the high pressure at the respective discharge ports.

Abstract: A braking pressure control apparatus for a braking system having brake cylinders including a pressurizing device capable of pressurizing a working fluid and controlling a pressure of the pressurized fluid, a plurality of pressure control valve devices each of which is disposed between the pressurizing device and at least one of the brake cylinders and is operable to control flows of the fluid between the pressurizing device and the corresponding at least one brake cylinder, for thereby regulating the fluid pressure in the corresponding at least one brake cylinder, and a pressurizing-device control device operable to control the pressurizing device for controlling an output pressure of the pressurizing device on the basis of an operating state of each of the pressure control valve devices, which operating state determines the state of fluid flow between the pressurizing device and the corresponding at least one brake cylinder.

Abstract: A drum brake device produces a stable braking force at a predetermined boosting ratio in response to a brake operation force input thereto, even if the friction characteristics of the interface of the brake drum and the brake shoe varies, without increasing the size of the wheel cylinder.

Abstract: The pump is connected on its delivery side through an auxiliary passage to a primary passage connecting the master cylinder and brake cylinder to each other, and a pressure control valve is provided in a portion of the primary passage between the master cylinder and a point of connection thereof to the auxiliary passage. The pressure control valve releases working fluid from the pump to the master cylinder when delivery pressure of the pump is higher than the master cylinder pressure by more than a predetermined amount, and the pump is activated when the fluid pressure generated in the brake cylinder is required to be higher than the master cylinder pressure, during brake operation.

Abstract: An inexpensive hydraulic brake system for a vehicle including an antilock device, by means of which brake pressures in front wheel brakes and rear wheel brakes of a four-wheeled vehicle that are connected to diagonal brake circuits can be changed to a large extent independently of one another in order to reduce or eliminate the danger of wheel locking. The antilock device should have one return feed pump per brake circuit. The brake system is equipped with the antilock device with a total of six electrically controllable valves. In each of the brake circuits a first valve is disposed between the master cylinder and a front wheel brake and a second valve is disposed between the master cylinder and the rear wheel brake and a third valve is disposed between the front wheel brake and an inlet of each of the return feed pumps.

Abstract: A vehicle brake apparatus includes a brake pedal, a wheel brake cylinder operatively mounted on a wheel for applying a braking force to the wheel in proportion to a hydraulic braking pressure, a pressure source for pressurizing brake fluid to generate a hydraulic braking pressure and supply the hydraulic braking pressure to the wheel brake cylinder, and an auxiliary pressure source for pressurizing brake fluid in response to operation of the brake pedal to generate a hydraulic braking pressure and supply the hydraulic braking pressure to the wheel brake cylinder when the pressure source is non-operational. A mechanical valve is operatively mounted between the wheel brake cylinder and the auxiliary pressure source. A first passage is connected between the auxiliary pressure source and the mechanical valve and a second passage is connected between the mechanical valve and the wheel brake cylinder.

Abstract: An electro-hydraulic braking system for motor vehicles. The system includes a brake pedal and a braking device associated with at least one vehicle wheel which is brought into communication with an electronically controlled valve arrangement in order to apply hydraulic fluid under pressure to the braking device. A fluid pressure accumulator fed by the pump provides a pressurized hydraulic fluid which can be passed to the braking device by way of an electronically controlled valve arrangement in order to apply hydraulic fluid in proportion to the driver braking demand as sensed at the brake pedal in the “brake by wire” mode. A first device within the system provides a level of fluid pressure supply within the electro-hydraulic system whose highest value is less than that sufficient for the maximum possible braking demand level which may be required.