A device for filling a hydraulic circuit of an electro-hydrostatic system provided with a discharge valve and a filling valve includes a vacuum generator designed to be connected to the discharge valve via a first shut-off valve in order to eliminate the air or gases present in the circuit, and a source for supplying pressurised hydraulic fluid, which source is designed to be connected to the filling valve via a second shut-off valve and to the discharge valve and the first shut-off valve via a third shut-off valve in order to fill the hydraulic fluid circuit.

Provided is an electrohydrostatic actuation system including an emergency shut-off circuit to be actuated stably with a simple configuration. The electrohydrostatic actuation system includes: a hydraulic cylinder (24) including a piston (25) to which a valve element is connected, a first chamber (24A), and a second chamber (24B); a hydraulic pump (21) configured to supply hydraulic fluid to the first chamber (24A) or the second chamber (24B); a servo motor (M) configured to drive the hydraulic pump (21); a shuttle valve (11) configured to establish communication to a downstream side under a state in which a hydraulic pressure generated by the hydraulic pump (21) is maintained; a solenoid valve (12) configured to receive the hydraulic pressure via the shuttle valve (11) as a pilot pressure; and a logic valve (13) including a first port configured to receive the pilot pressure from the solenoid valve (12), and a second port to be communicated to the first chamber (24A) of the hydraulic cylinder (24). When the solenoid valve (12) is brought to a de-energized state, the pilot pressure of the logic valve (13) is released, and the logic valve (13) causes the hydraulic fluid in the first chamber (24A) communicated to the second port to flow into the second chamber (24B) so that emergency shut-off of the valve element is achieved by a return spring (26).

A hydraulic system includes a first electric machine connected to a first hydraulic machine and a second electric machine connected to a second hydraulic machine. An output side of the second hydraulic machine is connected to an input side of the first hydraulic machine. A hydraulic consumer is hydraulically coupled to an output side of the first hydraulic machine via a supply line and is powered by the first hydraulic machine. A return line hydraulically couples the hydraulic consumer to an input side of the first hydraulic machine. The second hydraulic machine provides a flow of hydraulic fluid to the input side of the first hydraulic machine if a requested flow from the first hydraulic machine exceeds a flow of the return line and recuperates energy if the requested flow from the first hydraulic machine is lower than the flow of the return line.

The disclosure relates to a hydraulic control block for controlling a pressure medium supply of a hydraulic cylinder of a hydraulic spindle. The hydraulic control block includes a generic hydraulic switching structure electively configurable in each of a plurality of specific hydraulic switching structures, each of the plurality of specific hydraulic switching structures having a respective hydraulic cylinder with a number of piston areas which differs from a number of piston areas in the respective hydraulic cylinders of each of the other of the plurality of specific hydraulic switching structures.

A portable hydraulic power unit includes a frame, a fluid tank supported by the frame, and a manifold supported by the frame. The fluid tank is configured to store a supply of hydraulic fluid for powering a hydraulically-driven tool. A reciprocating pump is mounted on the exterior of the fluid tank and on the exterior of the manifold. The reciprocating pump is secured to the fluid tank and the manifold with fasteners extending through a cylinder body of the reciprocating pump.

A hydraulic system for a work vehicle includes a first pump providing a first flow to a first circuit. A first pressure sensor measures a first pressure in the first circuit. A first swashplate angle sensor measures a first angle of a first swashplate of the first pump. A supplemental pump provides a supplemental flow to a supplemental circuit. A supplemental pressure sensor measures a supplemental pressure in the supplemental circuit. A supplemental valve adjusts the load sense signal provided to a supplemental load sensing compensator of the supplemental pump. A first valve selectively enables flow from the supplemental circuit to the first circuit when the supplemental pressure is equal to or greater than the first pressure. A controller determines to operate the supplemental pump in one of a standby condition and a use condition based in part on the first angle of the first swashplate.

A hydraulic system for a work vehicle includes a first pump providing a first flow in a first circuit having a first pressure. A first load sense circuit connected to a first load sensing compensator of the first pump. The first load sense circuit having a first load sense pressure. A supplemental pump provides a supplemental flow to a supplemental circuit having a supplemental pressure. A supplemental load sense circuit connected to a supplemental load sensing compensator of the supplemental pump. A first supplemental valve selectively enables flow from the first load sense circuit to the supplemental load circuit based in part on a first pressure differential between the first pressure and the first load sense pressure. A first valve selectively enables flow from the supplemental circuit to the first circuit when the supplemental pressure is equal to or greater than the first pressure.

An electro-hydraulic actuator system includes a fixed-displacement hydraulic pump and a variable speed electric motor configured in combination to constitute an individual electro-hydraulic unit that is coupled to an actuator, and a bypass valve in parallel to the actuator. The system is configured to enable the actuator to be operated at actuation speeds that are higher than a maximum actuation capability of the pump at the maximum flow capability thereof, and at actuation speeds that are lower than a minimum actuation capability of the pump at the minimum flow capability thereof. The actuation velocity of the actuator may be controlled by controlling the speed of the electro-hydraulic unit and a size of an opening of the bypass valve.

An intelligent work vehicle filtration system includes a hydraulic subsystem, a controller architecture, and an electric drive subsystem containing a battery pack. A hydraulic subsystem includes, in turn, a fine filter device having a first filter efficiency, a coarse filter device having a second filter efficiency less than the first filter efficiency, a hydraulic circuit in which the fine filter device and the coarse filter device are positioned, and a hydraulic pump controllable to circulate hydraulic fluid about the hydraulic circuit. During operation of the intelligent work vehicle filtration system, the controller architecture selectively places the intelligent work vehicle filtration system in an externally-powered filter mode in which hydraulic flow is directed through the fine filter device, while bypassing the coarse filter device, when the electric drive subsystem is electrically coupled to an external power supply utilized to charge the battery pack.

The claimed invention is an end-of-stroke recirculation system for use with a hydraulic cylinder. Generally speaking, the fluid in a hydraulic cylinder remains trapped on one side of the piston and is unable to recirculate. The claimed invention provides a bypass that allows for hydraulic fluid to circulate through a cylinder when the hydraulic cylinder is at either end or both ends of its stroke.