Disclosed is an electric hydraulic actuator including a hydraulic cylinder and the hydraulic power generator. The hydraulic cylinder includes a hollow rod that is connected to a piston and is linearly movable to protrude outward or to retract. The hydraulic power generator includes a motor, a fluid tank, and a gear pump and a pilot check valve disposed in a pump housing. The cylinder housing and the pump housing are directly coupled to each other. The cylinder housing includes a first port through which the working fluid is transferred to a first side of the piston and a second port connected to a return pipe that is provided in the hollow rod. The pump housing includes a third port that is configured to communicate with the first port and a fourth port that is configured to communicate with the second port.

Some embodiments of a gearbox for an irrigation system can comprise a housing, a worm gear within the housing, a bull gear within the housing and configured to be engaged with the worm gear, a diaphragm, and a vent. The diaphragm can define a chamber configured for expansion and contraction and configured to be positioned inside the housing to relieve pressure build-up within the housing. The vent can be configured to allow air to flow between the atmosphere and the chamber.

In a system including a reservoir tank RSV integral with a master cylinder M/C, an inlet fluid passage 16 for connecting an inlet portion 22 of a pump P to the reservoir tank RSV, a pressure reducing fluid passage 32 that connects the inlet fluid passage 16 to wheel cylinders W/C and a normally closed pressure reducing vale 30 that is connected to the pressure reducing fluid passage 32 and opened when it is intended to depressurize a brake fluid to in the wheel cylinders thereby to return the brake fluid to the reservoir tank through the inlet fluid passage 16, there is employed a normally closed reservoir shutting valve 31 that is connected to the pressure reducing valve 30 in series with respect to the wheel cylinders W/C and the reservoir tank RSV.

This invention relates to a four-state adjustable air path structure. An air source is connected to an air storage tank and a first two-position three-way solenoid valve via a check valve. The first two-position three-way solenoid valve is connected to a second two-position three-way solenoid valve and a vent hole. The second two-position three-way solenoid is connected to a third two-position three-way solenoid valve and a port of a throttle valve. Another port of the throttle valve is connected to the third two-position three-way solenoid valve. The third two-position three-way solenoid valve is connected to an air tank. The present four-state adjustable air path structure simplifies processing and maintenance of a mechanical structure. Intellectual control of an operating speed can also be achieved. The present invention has advantages such as structural simplicity, low manufacturing costs, safe and reliable operation, long service life, and suitability for long-distance transmission.

An aircraft assembly having: a first part; a second part, the second part being movably mounted with respect to the first part; an electro-hydraulic actuator coupled between the second part and a first anchor point, the actuator comprising a cylinder defining a bore and a piston and rod assembly slidably mounted within the bore and an active chamber within which an increase in fluid pressure causes the actuator to change during a first phase between first and second extension states to move the second part relative to the first part. The electro-hydraulic actuator further includes a hydraulic fluid supply circuit comprising a piezo-electric pump operable to supply pressurised fluid to the active chamber to change the actuator between first and second extension states.

In a steam valve driving apparatus according to an embodiment, a control valve permits or blocks a flow of hydraulic oil from a supply port to an opening direction piston chamber. A dump valve blocks or permits the flow of the hydraulic oil from the opening direction piston chamber to a discharge port. A blocking valve permits or blocks a flow of the hydraulic oil from an accumulator to a closing direction piston chamber. The control valve permits the flow of control oil from the closing direction piston chamber to the discharge port in a state where the flow of hydraulic oil from the supply port to the opening direction piston chamber is permitted.

An electrohydraulic system for use at great water depths includes a vessel, a hydrostatic machine, and an electric machine. The vessel has an interior space configured to form a volume that is closed off with respect to the surroundings and that accommodates a hydraulic pressure fluid. The vessel includes a compensation piston configured to subject the hydraulic pressure fluid in the interior space to at least approximately the pressure prevailing in the surroundings. The hydrostatic machine is configured to be operated as a pump. The electric machine is mechanically coupled to the hydrostatic machine and operates as an electric motor in order to operate the hydrostatic machine as a pump. The hydrostatic machine and the electric machine are arranged in the interior space of the vessel. The compact electrohydraulic system fits on existing installations and on new installations. The electrohydraulic system also includes a compact process valve.

A pneumatic actuator (240), comprising: a pressure reducer (270) for delivering gas under a reduced pressure to a control valve; the control valve (280) selectively supplying gas to a pneumatic cylinder (290) or discharging gas from the cylinder (290) to the environment; a replaceable gas capsule (260) for supplying the gas under increased pressure; where the actuator has a first mode of operation for moving the piston (293) to the extended position, and has a second mode of operation for retracting the piston (293). A method for assembling a pneumatic actuator. A portable tool, a clamping device, a screw clamp comprising such a pneumatic actuator. A method for assembling the screw clamp. A method for repairing the screw clamp.

Hydraulic circuit comprising a low-pressure circuit (6) fed by a booster pump (4) that draws from a very-low-pressure reservoir (2), characterized in that this very-low-pressure reservoir (2) is leaktight and has a device for placing the internal volume (12) under negative pressure with respect to atmospheric pressure.

A self-contained pressure compensation system and a control method thereof are provided, wherein the self-contained pressure compensation system comprises an oil supply device, a pressure compensation device, a power unit associated with the pressure compensation device, and a switch control device, the pressure compensation device supplies oil to the power unit and detects a change in a chamber pressure of itself in real time, the switch control device triggers the oil supply device to supply oil to the pressure compensation device if the chamber pressure is less than a predetermined first threshold and triggers the oil supply device to stop supplying oil to the pressure compensation device if the chamber pressure is greater than a predetermined second threshold. The invention can detect a chamber pressure of the pressure compensation device in real-time and can achieve automatic oil refilling, and can provide pressure compensation for the power unit effectively.