The hydraulic system according to the invention comprises a hydraulic circuit with a low-pressure region and a high-pressure region; a volume- and/or speed-variable hydraulic machine, which is driven by a first electric motor and has an inlet and an outlet and provides a volume flow of a hydraulic fluid in the high-pressure region of the hydraulic circuit. The hydraulic system according to the invention further comprises at least one movable shaft, which is arranged in the high-pressure region of the hydraulic circuit; at least one valve, which separates the high-pressure region from the low-pressure region; and at least one hydraulic fluid container, which is hydraulically connected to the low-pressure region of the hydraulic circuit. The hydraulic system according to the invention also has a discharge line, which discharges hydraulic fluid from the leakage of the hydraulic machine, and a cooling line for transporting the hydraulic fluid in order to cool the electric motor, the discharge line and the cooling line being fluidically connected to at least one of the hydraulic fluid containers.

Disclosed are a micro electro-hydraulic linear actuator and a hand of an electro-hydraulic driving robot, comprising an actuator base, a spherical pump unit and a reciprocating piston mechanism encapsulated in a closed elastic leather bag. The actuator base is provided with a hydraulic cylinder and a cylinder liner, both of which are cylindrical chambers with an open at one end. An open end of the hydraulic cylinder is provided with an end cover of the hydraulic cylinder, an open end of the cylinder liner is provided with an end cover of the motor, the reciprocating piston mechanism is provided in the hydraulic cylinder, and the spherical pump and motor are integrated in the cylinder liner to form a spherical pump unit; the present application adopts a distributed hydraulic source as the driving force and does not need a directional valve.

Provided is a fluid actuator capable of safely driving a drive target. An air actuator using air as a working fluid includes an X-axis pressure sensor that measures air pressures PX+ and PX− along one drive axis, which drives a drive target in an X direction, a Y-axis pressure sensor that measures air pressures PY1+, PY1−, PY2+, and PY2− along two drive axes, which drive the drive target in a Y direction, and an acceleration detection unit that detects translational acceleration and rotational acceleration generated in the drive target on the basis of the measured air pressures PX+, PX−, PY1+, PY1−, PY2+, and PY2−.

Combination linear and rotary actuators are disclosed. The linear and rotary actuators have a housing defining a cylindrical interior space and a pair of pistons located inside the cylindrical interior space. An inner bearing cylinder is provided that has spaced-apart ball bearings arranged in a helical pattern on its surface that engage with a structure having an inner surface with helical grooves therein. The structure at least indirectly engages a linear drive piston that is slidably mounted in the housing, and provides rotational movement thereto. The linear drive piston has an input shaft that has ball bearings on its surface, and is inserted inside the output shaft of a revolution piston that has an inner surface with linear grooves. The actuators use hydrostatically charged integral bearing races that activate during operation to reduce friction. Combination linear and rotary actuators with double actuation output shafts are also provided.

A method and apparatus for remotely positioning a stabilizer wheel of a towable agricultural implement simultaneously, cooperatively and proportionally control the flow of hydraulic fluid to and from both the rod and base ends of the bore of a double-acting hydraulic cylinder, to hold the piston of the hydraulic cylinder at a target position determined from a desired position input signal corresponding to a desired position of the stabilizer wheel with respect to a frame of the agricultural implement.

A hydraulic power pack for use in a hydraulic system includes a reservoir configured to receive hydraulic fluid. A pump is in communication with the reservoir and is fluidly connectable to the hydraulic system. The pump is configured to pump hydraulic fluid from the reservoir into the hydraulic system when connected thereto. A hydraulic fluid sensor is fluidly connectable to the hydraulic system to sense a fluid characteristic of the hydraulic fluid within the hydraulic system. A variable speed drive is operatively coupled to the pump and the hydraulic fluid sensor to receive sensor data therefrom, with the variable speed drive being configured to generate a pump control signal based on the received sensor data. The pump is configured to operate at various speeds based on the pump control signal received from the variable speed drive.

The self-contained energy efficient hydraulic actuator system of the present invention includes a hydraulic cylinder, a servo motor that is configured to produce rated torque from zero RPM to maximum rated RPM with rotor speed/position feedback to a servo motor, a pump, and a solenoid valve that enables the hydraulic cylinder to maintain its position without the motor running. The system has the ability to hold a load in place without motor operation via the use of the solenoid valve, and therefore saves energy and extends the motor lifetime by minimizing the motor running time.

An actuator operable to move a valve stem between an opened position and a closed position includes a cylinder including an open side and a close side, the cylinder coupled to the valve stem, a first pump connected to the cylinder and operable to deliver a first high-pressure fluid to the open side of the cylinder to move the valve stem toward the opened position, and a second pump separate from the first pump, the second pump connected to the cylinder and operable to deliver a second high-pressure fluid to the close side of the cylinder to move the valve stem toward the closed position.

Systems and methods for protecting a turbomachine may include a trip throttle valve having a throttle valve assembly and a trip valve assembly. The trip valve assembly may include a plurality of trip valves fluidly coupled to a hydraulic cylinder of the throttle valve assembly via a first flow path and a second flow path in parallel with one another. The trip valve assembly may also include a plurality of isolation valves fluidly coupled to the hydraulic cylinder via the first flow path and the second flow path. The plurality of isolation valves may be configured to selectively prevent fluid communication between the plurality of trip valves and the hydraulic cylinder to allow testing of one or more of the plurality of trip valves during operation of the turbomachine.

The disclosure relates to an electro-hydraulic control system for directing fluid to at least one hydraulic actuator, the system comprising at least one electronic controller; first and second pilot valves being electrically connected to the at least one electronic controller which is arranged to control the operation of the first and second pilot valves, third and fourth pilot valves being electrically connected to the at least one electronic controller which is arranged to control operation of the third and fourth pilot valves. A pilot operated main valve is configured to control fluid flow to at least one hydraulic actuator. Each of the first and second pilot valves and the third and fourth pilot valves is a fail-safe pilot valve arranged to drain a regulated outlet port to a low pressure reservoir if a spool of the fail-safe pilot valve becomes stuck in an open state.