An hydraulic braking pressure control unit for a vehicle includes a first valve member installed at an intermediate point in a flow passage providing communication between the rear brake system of a tandem master cylinder and rear wheel cylinders, the valve member is adapted to open and close the passage, and a proportioning valve is normally urged in one direction to keep the valve member away from its seat to establish communication between the tandem master cylinder and the rear wheel cylinde...

A fluid pressure regulator assembly for pressure accumulators used in a dual pressure hydraulic brake system for vehicles. The regulator valve assembly is connected between an engine driven hydraulic pump and the accumulators to regulate the maximum pressure stored in the accumulators. The regulator valve assembly also includes an emergency shut-off valve and a one-way check valve for each separate hydraulic braking circuit and is responsive to a pressure difference between the two accumulators ...

A combined load-sensing proportion and relay valve comprising a valve disk having an exhaust passage in the axial center and held in a normally closed-valve condition, and a control piston assembly for adjustably moving the valve disk to open the valve, characterized in that the control piston assembly consists of three pressure-sensitive pistons, the third piston being formed in one piece with the first piston, the first piston having a downward projection extended from its underside, with the ...

An electromagnetic pump is disclosed in which a pair of check valves and a pressure-regulating mechanism are inserted in series in a fluid passage extending from a suction inlet to a discharge outlet and a pressure chamber operatively connected with a plunger is provided between the check valves. When a solenoid coil surrounding the plunger is supplied with an intermittent electric current, the plunger moves to and fro, thereby the pressure in the pressure chamber being varied to have the check ...

A hydraulic brake control assembly is provided in which a proportioning valve is actuated to reduce fluid pressure to be supplied to rear cylinders from a master cylinder in accordance with the vehicle deceleration. An inertia ball is adapted to control the movement of the proportioning valve via a flexible disc valve to increase or reduce the fluid pressure supply to the rear cylinders. The disc valve is deformable to open the proportioning valve if the pressure of the master cylinder exceeds a...

A fluid pressure regulator valve assembly for pressure accumulators used in a dual full pressure hydraulic brake system for vehicles. The regulator valve assembly is connected between an engine driven hydraulic pump and the accumulators to regulate the maximum pressure stored in the accumulators. The regulator valve assembly also includes an emergency shut-off valve and a one-way check valve for each separate hydraulic braking circuit and is responsive to a pressure differential between the two ...

A method for producing a worm shaft for use in a rotation control valve of a power steering mechanism. The worm shaft is formed with grooves which receive a control body and form therewith a fail safe structure. The grooves are formed evenly so that the permitted range of movement on either side of a neutral position is uniform. A cylindrical member is plastically deformed in two steps to form the outer side of the control valve. Then, while in a die having in inner shape corresponding to the de...

A power steering device having a fluid pressure cylinder of a single rod type providing like output characteristics for steering both rightwardly and leftwardly. A rod-side chamber and a head-side chamber of the fluid pressure cylinder have different pressure receiving areas. A control valve controls the changeover of a flow path among a pump, a tank and the rod-side and head-side chambers in accordance with the movement of a steering wheel such that the rod-side chamber is connected to the pump...

In an oil pump of the type comprising a cartridge having an elliptical cam ring in which a rotor having a plurality of vanes is rotated to form a pair of pump chambers symmetric with respect to an axis of rotor, and a pair of suction passages and two pairs of discharge passages are provided for the pair of pump chambers. A valve opening is formed coaxially with the rotor in a pump body secured to one side of the cartridge to contain the spool valve. A metering orifice is provided in a discharge ...

A combined load-sensing proportion and relay valve for an air brake system, comprising a valve disk having an exhaust hole in the axial center, and a control piston assembly for adjustably moving the valve disk to open the valve, characterized in that the control piston assembly consists of two pressure-sensitive pistons, the first of the pistons being formed with a downward projection having a valve seat at its lower end for face-to-face engagement with the valve seat, an indicated-pressure cha...