An electro hydrostatic actuator comprising a hydraulic pump driven by an electric motor to supply hydraulic fluid to a hydraulic actuator, the pump comprising an inlet and an outlet for the hydraulic fluid and an active flow path configured therebetween such that, in an active mode of operation when the pump is driven by the electric motor, hydraulic fluid is actively drawn in through the inlet and exhausted out through the outlet. The pump further comprises a bypass flow path configured to open between the inlet and outlet such that, in a damping mode of operation when the pump is not driven by the electric motor, hydraulic fluid is able to pass through the pump along the bypass flow path between the inlet and outlet. The hydraulic pump is a rotary piston pump comprising a pump barrel driven to rotate by a motor shaft.

The present disclosure relates to a motion control unit that is capable of receiving electrical power from an electrical power source and hydraulic power from a hydraulic power source. The motion control is configured to produce a blended power output derived from the electrical and hydraulic power which can be used to power a hydraulic actuator. The motion control unit can also split hydraulic power recovered from hydraulic actuator to the electrical power source and the hydraulic power source.

A hydraulic energy regeneration system for a work machine for boosting a pressure of a return hydraulic fluid of a hydraulic cylinder and regenerating the hydraulic fluid, prevents a bottom pressure from reaching an overload relief set pressure and suppresses a changeover shock to ensure favorable operability. The hydraulic energy regeneration system for the work machine, includes: a communication pressure boost passage that can boost a pressure of a discharge-side hydraulic fluid by communicating a discharge side and a suction side of the hydraulic cylinder with each other during an own weight fall of a driven body; a communication pressure boost valve that is disposed in the communication pressure boost passage and that can regulate one of or both of a pressure and a flow rate of the communication pressure boost passage; a reuse-side line and a reuse control valve or a regeneration-side line and a regeneration control valve that can regenerate a hydraulic fluid discharged from the hydraulic cylinder during the own weight fall of the driven body; and a controller. The controller is configured to reduce an opening degree of the communication pressure boost valve in response to an increase of the discharge-side pressure of the hydraulic cylinder right after the discharge-side pressure reaches a preset high load set pressure, and gradually reduces the opening degree of the communication pressure boost valve with passage of time.

A forklift includes forks, cylinders for causing the forks to perform an ascending/descending operation in accordance with the flow rate of hydraulic oil, a first valve for controlling the flow rate of the hydraulic oil in accordance with an energizing current, a second valve 6 for regulating the flow rate of the hydraulic oil in accordance with cylinder pressure, and a control portion that calculates the flow rate to be regulated by the second valve, on the basis of cylinder pressure detected by a pressure sensor, calculates a current command value for the energizing current, with the flow rate to be controlled by the first valve being set equal to the regulated flow rate, and changes the energizing current in two stages, with the current command value as the upper limit of the energizing current, thereby decelerating the forks in two stages when stopping the ascending/descending operation.

A system for automatically actuating a hydraulic accumulatoruseful for oil collection systemscapable of operation while maintaining a zero or near zero draw of electrical energy.

A cooling flow circuit is provided and includes a main line having first and second sections ported to piston extend and return sides of the gas turbine engine actuator, respectively, an orifice disposed along the main line between the first and second sections, a bypass line and a bypass valve. The bypass line is fluidly coupled to the first and second sections at opposite ends thereof, respectively. The bypass valve is disposed along the bypass line between the opposite ends thereof. The bypass valve has a variable flow area which is responsive to a pressure differential between the first and second sections.

A kinetic energy recovery system (KERS) for a machine having a swing motor and/or an actuator includes a hydraulic motor/pump that can output pressurized fluid for operating at least one of: the swing motor and the actuator. A first shaft of the hydraulic motor/pump can be rotated by fluid returning from at least one of: the swing motor and the actuator back to the hydraulic motor/pump. Further, the KERS also includes a flywheel that can selectively couple with the first shaft with the help of a first clutch. The flywheel stores drive power generated by the hydraulic motor/pump from the return flow of fluid when the first clutch couples the flywheel with the first shaft of the hydraulic motor/pump. A gearing arrangement is coupled to the flywheel and can selectively engage with a second shaft associated with a prime mover of the machine with the help of a second clutch.

Power machines having hydraulic systems and controllers configured to prohibit, limit, or allow full operation of the hydraulic systems based upon measured temperature of the hydraulic oil in the system are provided. Also included are methods of controlling the hydraulic systems. In the methods implemented by the controllers, determinations are made as to whether the temperature of the hydraulic oil is below a first (and lowest) set point temperature, above a second (and higher) set point temperature, or between the first and second set point temperatures. The controllers then either prohibit hydraulic system operation, allow limited hydraulic system operation, or allow full hydraulic system operation, based upon the measured temperature in comparison to the two or more set point temperatures.

This disclosure includes systems and methods for actuating hydraulically-actuated devices.

An air supply unit for a pneumatic system is provided herein. The unit includes a compressor inlet for receiving compressed air in a supply mode. The unit further includes a consumption outlet for connecting at least one consumption circuit. The unit further includes an air processing unit connected to the compressor inlet for drying and filtering the compressed air and delivering dried compressed air at its outlet. The unit further includes a supply line extending from the outlet to the consumption outlet. The unit further includes a purge tank connected to the supply line. The purge tank is connected to the supply line through a throttle for pressure reduction of the purge air. In order to realize a short filling time, the purge tank is further connected to the supply line by a filling valve. The filling valve is open in the supply mode and blocking in the purge mode.