A bistable hydraulic solenoid valve has a valve spool that transitions between two positions, remaining in one of the two positions under an attractive magnetic force when the solenoids are not energized. The valve spool has a first permanent magnet attached to one end and a second permanent magnet attached to the other end, so that the first permanent magnet faces a first solenoid, and the second permanent magnet faces a second solenoid. The first solenoid is energized to have a first polarity, and the second solenoid is energized to have an opposite polarity to concurrently push and pull the valve spool within the valve body between a first position and a second position, the first position establishing a first flow path and the second position establishing a second flow path through the valve body and valve spool so as to enable flow of hydraulic fluid.

An electromagnetic valve manifold includes an electromagnetic valve including an output port, a manifold base including an output passage, and a spacer arranged between the manifold base and the electromagnetic valve. The spacer includes a spacer block including a shaft hole and a manual shaft accommodated in the shaft hole. The spacer block includes an output connecting passage that is connected to the shaft hole and connects the output passage and the output port to each other. The manual shaft is configured to be manually operated to be switched between a first switching position, in which the manual shaft allows for connection between the output passage and the output port through the output connecting passage, and a second switching position, in which the manual shaft blocks the connection between the output passage and the output port through the output connecting passage.

Embodiments of the disclosure relate to a system designed to compensate for flow disturbances when changing a flow rate in the system. The system includes a flow source device having an inlet and an outlet. The inlet is configured to receive fluid at a first pressure, and the outlet is configured to output the fluid at a second pressure that is higher than the first pressure. The system also includes a fluid control device having an inlet port and a drain port. The inlet port of the fluid control device is configured to receive flow from the outlet of the flow source device. Further, the system includes a constant flow regulator configured to provide a leakage flow to a drain output. The constant flow regulator is configured to decrease the leakage flow in response to the drain port of the fluid control device.

Embodiments of the disclosure relate to a system designed to compensate for flow disturbances when changing a flow rate in the system. The system includes a flow source device having an inlet and an outlet. The inlet is configured to receive fluid at a first pressure, and the outlet is configured to output the fluid at a second pressure that is higher than the first pressure. The system also includes a fluid control device having an inlet port and a drain port. The inlet port of the fluid control device is configured to receive flow from the outlet of the flow source device. Further, the system includes a constant flow regulator configured to provide a leakage flow to a drain output. The constant flow regulator is configured to decrease the leakage flow in response to the drain port of the fluid control device.

A hydraulic oil control valve is coaxially disposed with a rotational axial of a valve timing adjustment device. The hydraulic oil control valve includes a sleeve, a spool slidably moving in an axial direction within the sleeve, and a filter member configured to capture foreign matters contained in the hydraulic oil. The sleeve includes an inner sleeve and an outer sleeve defining therein an axial hole extending in the axial direction. A space between the axial hole and the inner sleeve in a radial direction serves as a hydraulic oil supply passage. The filter member is disposed in the space to overlap with at least one of internal members in the inner sleeve when viewed in the radial direction.

A hydraulic oil control valve is coaxially disposed with a rotational axis of a valve timing adjustment device. The hydraulic oil control valve includes a sleeve and a spool sliding in an axial direction within the sleeve. The spool has an inner space serving as a drain passage through which the hydraulic oil discharged from a phase shifting portion flows. The spool defines a drain inlet that guides the hydraulic oil discharged from the phase shifting portion into the drain passage. At least one of the sleeve or the spool defines an opening through which the hydraulic oil in the drain passage is discharged from the hydraulic oil control valve. A protrusion is formed between the drain inlet and the opening to extend radially inward beyond the drain inlet.

A valve assembly includes a valve body defining a cylindrical passage therein about an axis. An inlet port is defined in or near a first end of the valve body. First and second outlet ports are defined in the valve body extending radially outward from the cylindrical passage. A cylindrical valve spool having a central passage is positioned within, and sealingly engaged with, the cylindrical passage. The valve spool is moveable along the axis among: a first position wherein the inlet port is in fluid communication with the first outlet port but not the second outlet port, a second position wherein the inlet port is in fluid communication with the second outlet port but not the first outlet port, and an intermediate position between the first and second positions wherein the inlet port is in fluid communication with both of the first and second outlet ports.

A hydraulic device with the position sensor feedback-controlled by a servo amplifier on the basis of a deviation between a command value of a command signal and a position sensing value from a position sensor includes: a computation processing section that outputs the position sensing value as a sensing signal; a communication device that transmits the sensing signal to the servo amplifier, and receives a signal from the servo amplifier; and a storage section storing characteristics information of the hydraulic device to be read via the communication device. The characteristics information at least includes: calibration information which is measured and acquired in advance in a test stand in a manufacturing process of the hydraulic device, and includes a position sensing value from the position sensor and a characteristics value of the hydraulic device, associated with each other; and flow rate characteristics information including a flow rate of the hydraulic device.

A spool is slidably located in a slide hole of a first housing. A second housing forms a servo chamber that is coaxial with the slide hole. A sleeve is slidably located in the servo chamber. A nut is fixed to a piston that is slidably fitted in the sleeve. An electric motor rotates a screw shaft screwed with the nut. The second housing includes an input port and a drain port. A first pressure chamber communicates with the input port. In a balanced state where forces applied to the sleeve from both sides are balanced, a second pressure chamber is blocked from the input port and the drain port by the piston. From the balanced state, when the piston shifts, the second pressure chamber comes into communication with the input port or the drain port.

A spool is slidably located in a slide hole of a first housing. A second housing forms a servo chamber that is coaxial with the slide hole. A sleeve is slidably located in the servo chamber. A nut is fixed to a piston that is slidably fitted in the sleeve. An electric motor rotates a screw shaft screwed with the nut. The second housing includes an input port and a drain port. A first pressure chamber communicates with the input port. In a balanced state where forces applied to the sleeve from both sides are balanced, a second pressure chamber is blocked from the input port and the drain port by the piston. From the balanced state, when the piston shifts, the second pressure chamber comes into communication with the input port or the drain port.