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 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: An antiskid control device which calculates an estimated fluid pressure of each of wheel cylinders under antiskid control in each control cycle so as to adjust a fluid pressure of each of the wheel cylinders on the basis of the estimated fluid pressure and behaviors of the wheels. The device includes a differential pressure detecting member which detects a difference between a fluid pressure of a master cylinder and the fluid pressure of each of the wheel cylinders so as to produce an output signal indicative of the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders. When the difference between the fluid pressure of the master cylinder and the fluid pressure of each of the wheel cylinders is found to be in the vicinity of zero, the estimated fluid pressure of each of the wheel cylinders is set to a predetermined value by stopping addition in calculation of the estimated fluid pressure.

Abstract: An arrangement for preventing the master cylinder of a brake system from getting damaged even if the brake fluid in the master cylinder reservoir is suctioned into the brake circuit during traction control. A wheel brake pressure control valve is provided in the main line. The system also includes a discharged fluid reservoir for storing fluid discharged from the control valve, a pump for returning the fluid in the discharged fluid reservoir into the fluid return point of the main line, a traction control changeover valve for checking any fluid flow from the fluid return point toward the master cylinder, and an intermediate reservoir provided in the supply line branching from the main line and adapted to communicate with the main line during normal braking. The system further includes a relief valve provided in a connecting line branching from the main line to check any fluid flow from the supply line toward the intermediate reservoir during traction control.

Abstract: A system and method of calibrating pressure transducers in an electro-pneumatic brake system for a railroad train in which a locomotive microprocessor generates a respective best fit curve for the train brake pipe, supply reservoir and brake cylinder pressures that approximates the actual train pressure therefore. These best fit curves are generated from the pressure transducer readings of these pressures at each car by employing an equation based on a fourth order polynomial. Each car is then provided with a theoretical reference pressure signal from the best fit curve for each of the mentioned brake pipe, supply reservoir and brake cylinder pressures, according to the position of the car in the train. The theoretical reference signal is then compared at each car with the car pressure transducer reading for the respective brake pipe, supply reservoir and brake cylinder pressures to obtain a transducer error correction factor that remains constant through a full range of pressures.

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: An anti-locking, hydraulic brake system is described comprising a master cylinder (4), a pressure fluid collector, at least one wheel brake (5) which, through a master pressure conduit (7), is in communication with the master cylinder (4) and, through a return conduit (12), is in communication with an auxiliary pressure pump (8), an electromagnetically actuated outlet valve (13) in the return conduit (12), and a hydraulically controlled inlet valve (6) in the master pressure conduit (7). The pump is connected to the wheel brake by an auxiliary pressure conduit having a throttle restriction therein. A control conduit branching from the auxiliary pressure conduit upstream from the throttle restriction operates the inlet valve.

Abstract: An anti-lock hydraulic brake system is provided which includes a master brake cylinder (2) and a pump (16) and an inlet valve (12) and an outlet valve (14). The inlet valve (12) is a minimum element whose control compartments (12, 22) are interconnected through a throttle (19). Depending on the position of a piston (20), either the brake line (8) or the return line (13) is opened. The pump (16) feeds the brake lines during a brake slip control operation. When the outlet valve (14) is opened, a pressure gradient is caused at the throttle (19) which results in that the operating piston (20) is displaced. As a result, the brake line (8) is closed and the return line (13) is opened, thereby permitting pressure fluid to discharge from the wheel brake (10) into the supply reservoir (15).

Abstract: A vehicle brake actuator has a piston (23) within a cylinder (22) for urging friction pad assemblies (19, 20) into braking engagement with a brake disc (21). The actuator incorporates a pressure accumulator (3) and an electrical valve (9) operable to supply pressure from the accumulator to the cylinder in response to the action of a brake pedal or other control device. The actuator may also incorporate a pump (1) for charging the accumulator, together with other equipment such as skid control device. A braking system incorporates one or more of the actuators and device for producing an electrical output in response to displacement of the brake control device for supply to the valve.

Abstract: In an automatic train-line air brake pressure monitoring system, a peak detector and hold circuit determines the peak voltage of an input signal representing the air pressure in the air brake system. A signal representing the present peak voltage of the input signal from the previously detected peak voltage is subtracted from the presently detected peak voltage to provide a subtraction output signal such that signals representative of the air brake pressure can be generated. The monitoring system may provide emergency air brake condition signals, as well as a number of programmable monitoring signals representative of different pressures within the air brake pressure system.

Abstract: An adaptive braking system for a vehicle having fluid pressure operated brakes includes a skid detecting circuit for generating a skid detecting signal when an incipient skidding condition is detected, a pressure command generator which is responsive to the skid detecting signal for generating a pressure command signal, and a duty cycle translator responsive to the pressure command signal to actuate the brake pressure modulator. The duty cycle translator includes a circuit which generates a signal modeling the actual pressure level in the vehicle brake actuators. Since the modulator is actuated by a solenoid which is powered by the vehicle electrical supply, the opening and closing times of the solenoid will vary as a function of the power output of the vehicle power supply, which can vary over a substantial range depending upon ambient temperature and upon the strength of the vehicle battery.

Abstract: A combined vehicle antiskid and load-dependent brake control system in which digital control of the individual wheel brake pressure regulating valves is provided. These regulating valves may be operated individually or on a per axle basis to vary the brake pressure independent of the operator-controlled brake valve device. The load-dependent brake control portion of the system includes electronic control circuitry that is subject to the output signal of sensors, which monitor pressure supplied by the brake valve device, actual brake cylinder pressure and the load supported by the vehicle rear axle, in order to operate the regulating valve of at least one wheel brake cylinder such as to cause the wheel brake pressure to follow a predetermined curve that differs from a normal brake pressure buildup curve.