Abstract: An improved cold temperature compensation control method for an EH braking system in which cold temperature operation is detected without requiring a temperature sensor. An electronic controller monitors the pressure developed by one or more electrically operated boost units for a characteristic pressure profile that occurs in cold temperature operation of the braking system, and adjusts the control strategy when the characteristic pressure profile is detected. The characteristic pressure profile is deemed by its frequency and amplitude parameters; specifically, a frequency above a threshold frequency, and an amplitude above a threshold amplitude. In a first mechanization, the controller responds to a detected cold temperature operation by reducing the gain of a closed-loop pressure control, while in a second mechanization, the controller responds by switching from the closed-loop pressure control to a closed-loop position control.

Abstract: In a hydraulic braking system, during normal service braking, the output from a master cylinder (3) is disabled and a brake (12) is applied from a high pressure hydraulic source (24) under the control of electric control means (30) including a solenoid operated actuator (6) responsive to electrical signals from a transducer (2) associated with the pedal (1), and upon failure of the electrical control means a direct flow path is defined between the master cylinder (3) and the brake (12) and through which the brake can be applied from the master cylinder by movement of the pedal in the "push through" mode.

Abstract: A braking system comprises a main pump supplying a fluid pressure to an intermediate circuit section between a master cylinder and a wheel cylinder, a fluid pressure control valve controlling wheel cylinder brake fluid pressure. By driving the pump and controlling the valve, a control unit controls the braking force independently of the driver's brake operation to achieve a vehicle stability control. A relief valve is disposed in a relief circuit bypassing a gate valve between the master cylinder and the wheel cylinder. The relief valve has a movable valve element having an opening pressure receiving portion for receiving a downstream pressure of the gate valve, and a closing pressure receiving portion receiving a fluid pressure in a closing pressure chamber. The closing pressure chamber is separated from the relief circuit, and the pressure in the closing pressure chamber is independent of the pressure in the relief circuit.

Abstract: A device for detecting operation of a brake pedal comprises: a first hydraulic chamber 9 in which fluid is pressurized by a first piston 7 connected with a brake pedal 1 when the brake pedal 1 is pushed downward; a second hydraulic chamber 13 communicated with the first hydraulic chamber 9 via an orifice 11 of small diameter; a first hydraulic pressure sensor 19 for detecting hydraulic pressure in the first hydraulic chamber; and a second hydraulic pressure sensor 20 for detecting hydraulic pressure in the second hydraulic chamber. The control unit 24 controls a motor (braking device) 22 in accordance with a difference .increment.P in pressure obtained by the values of detection conducted by the first hydraulic pressure sensor 19 and the second hydraulic pressure sensor 20.

Abstract: A vehicular anti-skid control apparatus comprises a differential pressure detector for detecting the pressure difference inside brake lines of separate brake channels, a brake failure detector for detecting failure in one of the brake channels based on the anti-skid control state of each brake channel, a brake failure evaluator for evaluating failure of the brake system based on both output signals of the differential pressure detector and brake failure detector wherein the anti-skid control method is changed from normal anti-skid control to a particular anti-skid control when a brake failure occurs.

Abstract: A hydraulic brake apparatus includes a control valve having a spool which is bi-directionally movable between a first position and a second position, the spool, when located at the first position, allowing brake fluid from a low-pressure source to pass through the control valve to a wheel cylinder, and the spool, when located at the second position, allowing brake fluid from a high-pressure source to pass through the control valve to the wheel cylinder. A first unit introduces brake fluid from the wheel cylinder into the control valve, the brake fluid having a wheel cylinder pressure exerted to move the spool in a first direction toward the first position. A second unit introduces brake fluid from a master cylinder into the control valve, the brake fluid having a master cylinder pressure exerted to move the spool in a second, reverse direction toward the second position. A third unit reduces the master cylinder pressure exerted on the spool.

Abstract: A rotary actuated braking system includes a motor driven shaft that operates two pairs of piston pumps and an allocation valve which, in combination with a single solenoid valve, effects ABS operation of the braking system. A combination of pressure operated control valves and pressure operated release valves for each control wheel brake respond to operation of the rotary actuator and solenoid valve to effect ABS pressure release and reapply from the corresponding wheel brake. A power boosted master cylinder provides base brake operation independent of the rotary actuator effected ABS operation.

Abstract: A brake pressure control device is capable of realizing reduction in a braking distance of a vehicle by promoting control in decreasing brake pressure applied on wheel braking force generating members such as wheel cylinders or a response function in increasing the brake pressure applied on the wheel braking force generating members in generating braking force on wheels.

Abstract: A hydraulic brake system with slip control, including a braking pressure generator hydraulically connected to at least one wheel brake by way of a main pressure line, a return line connected to the wheel brake and to the suction side of an auxiliary-pressure pump, an auxiliary-pressure line hydraulically connected to the braking pressure generator, and inlet and outlet valves inserted into the main pressure line and the return line and either closing or keeping open the pressure fluid passage in the main pressure line and in the return line, wherein a restrictor is controllable in the main pressure line between the inlet valve and the wheel brake permitting an unhindered hydraulic fluid passage in the main pressure line to the wheel brake in a first operating position, while the restrictor limits the pressure fluid flow to the wheel brake in another operating position.

Abstract: A hydraulic braking apparatus for braking a vehicle wheel, wherein a pressure control valve is disposed between a master cylinder and a wheel brake cylinder, and between a reservoir and a hydraulic pressure source which is independent of the master cylinder and whose pressure is applied as a braking pressure to the wheel brake cylinder for braking the wheel. The pressure control valve controls the braking pressure as a function of the master cylinder pressure which is generated by the master cylinder, depending upon the operating force acting on a brake operating member. An electrically controlled pressure regulating device is provided for applying an electrically controlled force to the pressure control valve, to thereby regulate the braking pressure to be applied to the wheel brake cylinder.

Abstract: An anti-skid control device is provided that eliminates noise and vibration, provides better pedal responsiveness, and provides better anti-skid control. In the anti-skid control device 1, a pressure regulator valve 4 is positioned in the brake line between the master cylinder 12 and inlet valve 21, and the pressure differential between the input side and output side of the inlet valve 21 is minimized.

Abstract: Links are provided for linking a brake caliper pivotally supported through a pin to a vehicle body. A master cylinder is fixed to the vehicle body and is constructed of a first link having one end pivotally supported through a pin to the brake caliper and the other end pivotally supported through a pin to an input member of the master cylinder. A second link is provided having one end pivotally supported through a pin to the vehicle body and the other end pivotally supported through a pin to the first link at an intermediate portion thereof. When the brake caliper is swung in a first direction by a brake reaction force received from a brake disc, the input member is upwardly driven through the first link and the second link, and the master cylinder is operated to generate a secondary brake hydraulic pressure.

Abstract: Following a general trend, the present invention provides an anti-locking hydraulic brake system to which a brake force controller has been added. However, as opposed to the prior state of art, the brake force controller (21) according to the invention is blocked only once the pump (18) builds up pressure. This means that in any uncritical deceleration, the brake force controller (21) performs its pressure reducing function as soon as the switch-over pressure thereof is attained. This will involve the advantage over other brake force controls actuated only upon failure of the anti-locking function that jamming or seizing of operative elements of the controller is prevented from occurring and that, in addition, a slip control will be required less frequently.

Abstract: A vehicle hydraulic brake system having an anti-lock protection device and an automatic braking system, particularly when driving around bends. During automatic braking, an auxiliary pressure source supplies a pressure instead of the main brake cylinder and this pressure can be individually set by pressure reduction in the wheel brakes by means of the anti-lock protection device. For this purpose, cylinders with separating pistons are located between the auxiliary pressure source and the anti-lock protection device. The auxiliary pressure source supplies substantially lower auxiliary pressures than known systems by supplying pressure to the inlets of feed-back pumps by arranging valves which permit temporary pressure increases to the extent necessary for automatic braking by means of these feed-back pumps. The system requires less energy and less noise is caused in automatic braking operations.

Abstract: The invention is directed to a hydraulic braking system having a master cylinder (10) in which a first piston and a second piston are slidably disposed to define a first pressure chamber (11) and a second pressure chamber (12). A valve device (24) is provided between the first pressure chamber and a reservoir (20). A first pressure control device (30, 31) is provided between the first pressure chamber and wheel cylinders (38, 39), and a second pressure control device (32, 33) is provided between the second pressure chamber and wheel cylinders (40, 41). A pump (27) is provided in a passage connecting the reservoir and the first pressure control device, and driven to supply a brake pressure from the former to the latter.

Abstract: A system and method for determining vehicle mass relative to a previous mass of the same vehicle utilizes a closed-loop control system to bring the vehicle to a controlled deceleration upon initiation of the procedure. The relative mass of the vehicle is determined by sensing the applied braking pressures at each of the vehicle axles and processing that information to generate the total braking force being applied to the wheels of the vehicle. Since a greater mass requires a greater braking force to achieve the same deceleration, the necessary braking force is indicative of the relative vehicle mass. An appropriate braking mode such as work balance, proportioning, or ABS, can then be determined based on the relative vehicle mass to better control subsequent braking maneuvers.

Abstract: A control method and an apparatus therefor, in which the braking force distribution to rear wheels is increased in a normal state, while the braking force distribution to the rear wheels is reduced to prevent the rear wheels from being locked in an early stage when the road surface is slippery. There are provided a pressure sensor (74) for detecting a master cylinder pressure, proportioning valves (57.sub.1, 57.sub.2) arranged in passages which connect a master cylinder and rear wheel cylinders and adapted to operate so that the ratios of the wheel cylinder pressures to the master cylinder pressure are low in a region where the master cylinder pressure is not lower than a predetermined pressure, normally-open switching valves (62, 63) by-passing the two valves, and a controller (71).

Abstract: A distributor for controlling the distribution of fluid to a brake system which includes an anti-lock and an anti wheelspin function and in particular functional operation during a brake condition wherein the front wheels are actuated at the same time a single back wheel is actuated.

Abstract: A vehicle antilock braking system having an operator controlled master cylinder for developing a first source of pressurized fluid and a second source of pressurized hydraulic fluid for selectively supplying rebuild pressure after an antilock event to simultaneously provide for actuation of each wheel braking device. A solenoid operated first flow control valve for each wheel controls communication of either the first source or second source of pressurized hydraulic fluid to the braking device and the braking device to a low pressure return. A hydraulically operated second control valve has a first inlet port connected to receive the first source of hydraulic pressurized fluid and a second inlet connected to receive the second source of hydraulic fluid and an outlet port connected to the first flow control valve.

Abstract: An anti-lock hydraulic brake system is disclosed with a flow control valve in the brake line. To prevent the flow control valve from performing its control function during a normal braking operation, a retaining piston works in conjunction with a spring such that the retaining spring bears against a piston of the flow control valve and retains the flow control valve piston in its initial position during normal braking operation. The retaining piston also serves as a valve closure member for a valve in the return line.

Abstract: A full-function brake valve for a tandem trailer is contained within a single housing and provides a boost to the control air signal arriving at the full-function valve so that the control air signal can be delivered to a second trailer full-function valve without degradation of the control air signal. The signal boost function is provided by an aperture in the piston of the relay valve that connects the control air inlet to the supply air, to cause the supply air pressure to boost the control air signal.

Abstract: A relay valve device for a relayed type brake system in which the compressed air of the auxiliary reservoir is connected to an equalizing reservoir instead of directly to the brake cylinder, as in a conventional system. Since the equalizing reservoir volume is fixed, as compared to the brake cylinder volume which varies with piston displacement, the equalizing reservoir volume must be greater than the final brake cylinder volume in order to obtain a full equalization pressure that matches the full service application pressure in a conventional brake system. The relay valve device employs a control piston that is subject opposingly to the equalizing reservoir pressure and the effective brake cylinder pressure delivered by the relay valve device.

Abstract: A full function brake valve for a semi-trailer is contained within a single housing and provides ports for receiving supply air and control air, and for delivering and receiving air from reservoirs, service brakes and spring brakes, and delivering air to an exhaust. The internal valves include a pressure protection valve which communicates with a first check valve and a quick release valve to pressurize spring brake chambers, and a reservoir check valve and a relay valve to respectively pressurize a reservoir and to deliver supply air to service brakes. An orifice preferably provided in a second check valve permits partial air flow to the spring brakes to release the spring brakes for towing the vehicle.

Abstract: An antilocking brake fluid pressure control unit for a vehicle includes a fluid pressure control device which receives an antilocking operation signal for controlling the pressure applied to a wheel brake. A pump in a parallel flow circuit returns a brake working fluid. A damping chamber (13) is connected to a fluid passage (9) between an outlet port of the pump and a feedback point (15). A filter is provided in the fluid passage (9) between the damping chamber (13) and the feedback point (15). Due to this structure, air bleeding from a brake piping system is simplified when assembling the brake system in a vehicle, and the time needed for charging a working fluid into the brake system is reduced.

Abstract: A hydraulic antilock brake system is described, with a multi-way valve hydraulically switched to connect the brake pressure generator (1) to the wheel brake (2), controlling, in response to the pump pressure prevailing in the auxiliary pressure conduit (4), the pressure fluid connection between the brake pressure generator (1) and the wheel brake (2). The valve (3) is switched by pump pressure in the absence of pressure from the brake pressure generator, but held or switched open if the brake pressure generator is operated. This allows a low-cost adaption to traction slip control with no need for additional electronic controls while substantially preserving the basic circuit configuration, especially the electronic control system.

Abstract: A pressure transmitter for a brake control system is provided with a piston having a passage extending between an input pressure chamber and an output pressure chamber and a seal fixedly installed on one end of the piston for sealing closing an end of the passage. The seal is resiliently deformable for transmission of pressure between the input pressure chamber and the output pressure chamber. A pressure control valve for a brake control system includes a valve spool for controlling communication between a pressure source and a wheel cylinder for producing a control pressure which is boosted on the basis of a master cylinder pressure and a vehicle running condition, a set of plungers for urging the valve spool in the direction of increasing the control pressure in response to increase of the master cylinder pressure and a solenoid for urging in the valve spool in the direction of causing decrease of the control pressure in response to increase of current supplied to the solenoid.

Abstract: A system and method of controlling pressure in a wheel brake cylinder of a brake. The hydraulic cylinder is connected to an electrically driven pump and a flow control valve is connected between the pump and the wheel cylinder. The system and method operate to control the speed of a motor driven pump to generate a desired pressure in a cylinder of the brake; generate a differential pressure, in the flow control valve, proportional to pump flow and communication same to a spring biased valving element; cause the valving element to move, in response to pressure forces acting on the valving element, generated by the pressure differential, and the force of the bias spring, so as to selectively open and close an associated exhaust port, connected to a drain or sump, such that in the steady state an equilibrium condition is achieved where the pressure forces balance the spring force and the pressure in the hydraulic cylinder is constant.

Abstract: In a braking system for a motorcycle, a brake includes a plurality of applicators which are respectively operated by hydraulic braking pressures fed from first and second actuators, and a common antilock modulator is provided for controlling and reducing the hydraulic braking pressures from the first and second actuators. This makes the braking system having antilock control function simplified in structure.

Abstract: In brake systems with a large boosting factor, relatively high pressures in the tandem master cylinder during an anti-lock control operation caused by start-up of a pump are prevented by an adjusting member which is controlled in response to the wheel braking pressure, to act upon a pressure-reducing valve inserted upstream of a power booster, so as to limit the booster pressure.

Abstract: A hydraulic dual-circuit brake system with front/rear brake circuit distribution, an anti-skid system (ABS) and traction control (ASR) for motor vehicles including a four-channel hydraulic unit with control valves and with one return pump and a separate pump element for each brake circuit. An apparatus to supply brake pressure to the rear axle brake circuit in traction control has a reversing valve, which in traction control disconnects the rear-axle brake circuit from the master brake cylinder, and a pump feed apparatus, which upon activation feeds brake fluid into the pump element of the rear axle brake circuit.

Abstract: A pressure limiting valve has a valve closing member (ball), which is subjected to a hydraulic opening force and is indirectly subjected to a closing force generated by a compression spring which avoids hysteresis that impairs the switching behavior of the pressure limiting valve. A tappet, which passes through a sealing ring and is exposed to a control pressure, is also capable of acting in a closing manner upon the pressure limiting valve. When there is no operative control pressure, the tappet is pushed back by the opening of the pressure limiting valve and is retained in this position by frictional forces brought about by a sealing ring. The switching plays of the pressure limiting valve are free of frictional forces. The pressure limiting valve is suitable for use in hydraulic motor vehicle brake systems.

Abstract: A brake system having a master brake cylinder for producing a brake pressure controllable by a brake pedal and transmitting it to at least one brake circuit, which connects the master brake cylinder with corresponding wheel brake cylinders of the front and rear wheels. At least one shutoff valve for anti-skid control is incorporated into each main line of the brake circuits. A first and second brake circuit communicate downstream of the shutoff valves with a feed system, which has devices for feeding brake fluid at different pressures to the first and second brake circuit.

Abstract: A hydraulic braking system having wheel cylinders, a tandem type master cylinder with first and second output ports, a hydraulic pressure transmitting device with a free piston slidably received in a housing with an input chamber located on one side of the free piston connected to the first output port in the master cylinder and an output chamber on the opposite side of said free piston leading to the wheel cylinders. An on-off valve is included, adapted to cut off the communication between a valve chest and the wheel cylinder in response to the hydraulic pressure in a pilot chamber leading to the first output port becoming larger than the hydraulic pressure in the valve chest by at least a given value. A differential pressure generating device is interposed between the second output port and the valve chest to reduce the output hydraulic pressure from the second output port in the master cylinder by a predetermined value to apply the reduced hydraulic pressure to the valve chest.

Abstract: The electrically controllable pressure medium brake comprises an electric pressure means (EP) converter (1) to convert an electrical brake request signal into a brake pressure. By way of an emergency brake valve (1), this brake pressure (in the normal case) and a vehicle load-dependent emergency brake pressure limited by a limiting valve (12) (in an emergency), is fed to the brake cylinder (14). For vehicle load-dependent limitation of the emergency brake pressure, a second EP converter (1a) generates from a vehicle load-dependent, electrical signal a vehicle load-dependent pressure medium pressure, which is stored in a pressure medium reservoir (18) and is fed to the limiting valve (12) in order to control it. The second EP converter (1a) is closed in the currentless state, during a power failure, whereby the vehicle load-dependent pressure medium pressure is preserved and the limiting valve (12) can thus continue to limit the emergency brake pressure as a function of the vehicle load.

Abstract: A brake system with traction control, having a master brake cylinder for at least one brake circuit and having a brake booster is proposed. By operation of a pump, servo pressure is fed into the brake booster via a pressure connection provided on the brake booster, and the servo pressure reaches a pressure reservoir through a bore provided on the brake booster. From there, given a corresponding open passage position of magnetic valves, the servo pressure, via a supply line, reaches the pressure cylinder present in the brake booster, and in the pressure cylinder there is a valve slide that, via a servo piston, actuates a pressure rod leading to the master brake cylinder.

Abstract: The hydraulic braking circuit is fitted with a master brake cylinder controlled by a brake pedal and with a wheel-antilock device, for a motor vehicle. This device comprises a pressure generator (20), which is started up at the beginning of an antilock-braking sequence, for selectively supplying at least one wheel brake (5, 6), and a member for automatically isolating the wheel brake (5, 6) from the master brake cylinder (1) when the pressure generator is started up by bringing the wheel brake into communication with means for storing the brake fluid, means are provided for limiting the pressure of the hydraulic fluid provided by the pressure generator to a value which is function of the jamming pressure.

Abstract: The pressure in the wheel brake of the system is controlled by an inlet valve 15 and an outlet valve 17 activated in response to the system controls. Fluid pressure from the pumps 13, is supplied to the wheel brake through the inlet valve 15, and discharged from the wheel brake through the outlet valve 17. By inserting a differential pressure limiter valve ahead of the inlet valve 15, the noise generated by the inlet valve is substantially reduced. A valve body 45 carries both the limiter valve seat and a discharge check valve seat, and respective closure balls 61, 62.

Abstract: A system for controlling the torque developed by a fluid actuated brake as it slows an aircraft wheel. In one embodiment, the system includes a strain gauge (62) for sensing the load applied to a brake metering valve (16). In another embodiment, the pressure of the hydraulic fluid output from the brake metering valve is sensed by a pressure transducer (42). Depending upon the sensor used, the system is operative to control the pressure applied to a brake assembly (54) of an aircraft as a function of the mechanical load or pressure. The system includes a torque control (50,120) connected to control one or more valves (22, or 83 and 102), modulating the pressure of hydraulic fluid applied to the brake assembly; the valves may be part of an antiskid control system. A torque sensor (46) is disposed on a torque reaction arm (36) and produces a signal indicative of the torque developed by the brake assembly.

Abstract: There is provided a brake system for a vehicle train which includes a tractor and a trailer, a source of high pressure air connected through an air control line to a pneumatic brake with the air control line in the tractor being connected to a fast-acting pressure switch which is activated by a higher pressure and a slow-acting pressure switch which is activated by a lower pressure, and with the fast-acting pressure switch operatively connected to open a valve to supply high pressure air directly to the trailer brake, and with said low pressure switch operatively connected to open the circuit which includes the fast-acting pressure switch.