摘要:
An anti-skid hydraulic braking system incorporates a modulator assembly (3) for modulating the supply of fluid from a master cylinder (2) to a brake (1) in accordance with skid signals. The modulator assembly (3) comprises a de-boost piston (9) located in a bore (8) in a housing (7), an expander chamber (48) connected to the brake (1), a first valve (14) between the master cylinder (2) and the chamber (48), and a second valve (28) for controlling the application to the de-boost piston (9) of a fluid sustained-support force. The modulator assembly (3) incorporates a safety piston (42) which prevents the first valve (14) from closing unless means, suitably an hydraulic accumulator (4) or pump (5), and which provides the fluid sustained-support force are operative.
摘要:
In an hydraulic system a solenoid-operated valve means (1) is used to control delivery of pressure fluid to a part (20) of the system, the fluid being circulated by a pump (15) from a reservoir (14) through the valve means (1) and back. To provide a light, low-powered solenoid valve which is still able to deal with the pressure generated, the valve means (1) has a solenoid-operated valve (6) biassed open, and closed when the solenoid-operated valve (6) biassed open, and closed when the solenoid (12) is energised to generate pressure fluid, the valve (6) then being operated in response to the pressure and a pressure-responsive valve-opening means (7), such that when the pressure rises above a first threshold level the pressure acts to keep the valve (6) closed, until the pressure reaches a second threshold level at which the valve-opening means (7) is operative to cause the valve (6) to open provided the solenoid (12) is de-energised. The valve-opening means (7) comprises a valve (34) which opens at the second threshold level to allow pressure fluid into a cavity (37) defined by a piston (33) to cause the pressure to fall and the valve (6) to open.
摘要:
In a high pressure hydraulic system a source (1) supplies pressurised fluid to a slave unit (7) through a control valve (3) operative to maintain the slave unit (7) in a desired condition. Leakage from the slave unit (7) past the control valve (3) when the source (1) is inoperative is undesirable, but it is difficult to provide durable leakproof seals and to minimise valve operating forces at high fluid pressures. The control valve (3) therefore comprises two solenoid-operated valves (11, 12), oppositely acting and arranged in series between the source (1) and the slave unit (7), each valve (11, 12) being closed to prevent flow through the valve in a direction from the other valve and opened to permit flow in both directions, under the control of a solenoid (32, 38) and the pressure differential acting across the valve (11, 12), a seating portion (29) on a first valve (11) is of elastomeric material to provide a leakproof seal when that valve (11) is closed. In the construction shown the slave unit (7) is an hydraulic suspension strut, and the system is adapted as a vehicular suspension levelling system, with the valves (11, 12) and the source (1) being manipulated as required by an electronic control system.
摘要:
A servo mechanism for a rotary shaft (1) has an electric motor (5) mounted on the shaft to augment an input torque applied to the shaft, the motor (5) being operated by a controller (8) in response to signals from torque sensing means (9) mounted on the shaft (1). The two members (6, 7) of the electric motor (5), one carrying the field magnet means, and the other the variable current coils (10), are arranged for contra-rotation, with one fixed to and rotatable with the shaft (1), and the other driven from the shaft (1) by a gear train (11). This arrangement enables the efficiency of the motor (5) to be improved. The gear train (11) may be of the planetary or bevel type. The controller (8) may also be mounted on the shaft (1). The servo mechanism may be used in a power-assisted vehicle steering system, being mounted on the steering column.
摘要:
A torque sensor responsive to bodily twisting of a shaft (1) about its main longitudinal axis comprises a torque indicating member (10) adapted to be displaced with respect to a neutral position in response to twisting movement of the shaft (1). A transmission tube (2) is provided for translating a signal dependent upon twisting movement of the shaft (1) into non-torsional displacement of the member (10).
摘要:
An hydraulic braking system includes a primary pressure source (1) connected to a brake actuator and operable by a force input device (2). A fluid displacer (8) is actuated by an electrical stepper motor (11) operated by a controller (13) in response to action of said device 2, as sensed by a sensor (14). Fluid displaced from the displacer (8) is added to that displaced from the primary pressure source for application to the actuator. By suitable programming of the controller, servo-assistance and/or quick-fill modes can be produced by the displacer (8) and a wheel-slip correction facility can also be provided.
摘要:
A vehicle disc brake comprises a rotatable disc (1) to which pad assemblies (2) carried by a caliper assembly are applied by actuator means (5) including hydraulically-operated service piston means (7) and spring-operated hydraulically-released parking piston means (8), and an automatic adjuster (9) operating to compensate for wear of the pad assemblies. The brake is conveniently arranged for operation so that actuation of the parking piston means (8) occurs while the service piston means (7) is actuated. This reduces the clearances which have to be taken up by operation of the parking piston means (8), as the clearances in the brake have been taken up by operation of the service piston means (7). The clearances can be reduced further by use of a follower adjuster, comprising a screw-threaded first member (27,46) on the service piston means (7) and an adjuster member (30,47) rotatable on the member (27,46) to maintain a substantially constant clearance between itself and the parking piston means (8), and operative to transmit the parking load to the service piston means (7) when the parking brake is operated.
摘要:
A combined brake release solenoid valve (15-20) and motor driven debooster (22-30) has a plunger 23 forming part of the debooster, which, on brake re-application is moved to a flow-restricting position in which there is only a restricted connection between the brake master cylinder and the slave cylinder, so as to avoid over-rapid brake re-application. In one embodiment, the plunger is positioned to provide a stop for the solenoid valve. In another embodiment, the plunger coacts with a separate valve seat.