An electro-hydraulic valve actuator having a modular manifold assembly with a network of channels that fluidly connect a hydraulic cylinder assembly to a hydraulic power assembly. The hydraulic cylinder assembly includes a piston rod that can directly or indirectly open or close a process valve. The hydraulic power assembly has a main pump and motor, and the manifold assembly includes a main manifold block to which is mounted the hydraulic cylinder assembly and the main pump and motor. The main manifold block has pluggable channel ports that can be unplugged to provide fluid communication with corresponding channel ports of at least one auxiliary manifold block that can be mounted to and integrated with the main manifold block. The at least one auxiliary manifold block has either a second pump and motor or a manual override pump.

A hydraulic system, in particular a hydraulic transmission controller, includes a first pump, which provides a large volumetric flow for a cooling and/or lubricating device at an outlet, and a second pump, which provides a high pressure for at least one hydraulic load at an outlet. The hydraulic system also includes an additional active valve, which is connected upstream of the cooling and/or lubricating device, is connected to a system pressure valve and to at least one hydraulic load to be boosted in such a manner that in a boost state, the outlets of the two pumps are connected to the hydraulic load to be boosted via a boost line.

This hydraulic drive device for a work vehicle includes a main pump (1) of a variable displacement type or a fixed displacement type discharging pressure oil, a main flow passage (F1) for supplying pressure oil of the main pump to an actuator, a sub-pump (5) of a fixed displacement type discharging pressure oil, a sub-flow passage (F2) for making pressure oil of the sub-pump merge with the main flow passage and supplying the pressure oil to the actuator (2), a merging directional valve (6A) for connecting or cutting off the main flow passage and the sub-flow passage, a controller (30) for controlling operation of the merging directional valve, and a relief valve (7A) arranged in the sub-flow passage, in which the relief valve has a pressure override characteristic having a tendency that the relief pressure increases from a cracking pressure to a set pressure as a relief flow rate increases.

A hydraulic power system for a downhole device, including a first motor, a first hydraulic pump, a second hydraulic pump, a first main oil circuit, a second main oil circuit, a switching control module and a first execution module. The first motor has a first output shaft which drives the first hydraulic pump and has an oil outlet connected to an input end of the first main oil circuit and a second output shaft which drives the second hydraulic pump and has an oil outlet connected to an input end of the second main oil circuit; the first execution module is connected to an output end of the first main oil circuit; displacement of the first hydraulic pump is smaller than that of the second hydraulic pump; and the switching control module is connected between the first main oil circuit and the second main oil circuit.

A hydraulic system for a transmission of a motor vehicle, the system having first and second pumps for conveying hydraulic fluid into primary and/or system-pressure circuits so that an intended pressure prevails in the circuits. The system further including liquid retention means preventing a flow of hydraulic fluid conveyed by the second pump from being conducted through the first pump when the first pump is not conveying and the second pump is conveying, and preventing a flow of hydraulic fluid conveyed by the first pump from being conducted through the second pump when the second pump is not conveying and the first pump is conveying. The system additionally including a sailing-mode lubricating valve for controlling, by an open-loop system, a flow rate of hydraulic fluid conveyed by the second pump into the primary and/or secondary system-pressure circuits such that the intended pressure is set in the system-pressure circuits.

The present invention relates to an electric driven hydraulic power system for heavy equipment, and more particularly, to a hydraulic power system, which includes a hydraulic pump operated by a battery and a motor, a supply line for supplying a hydraulic oil that is supplied by the hydraulic pump, a plurality of actuators, and a controller for controlling the motor and the actuators, in which electrical efficiency is significantly improved. In particular, the present invention relates to an electric driven hydraulic power system in which a plurality of motors and a plurality of hydraulic pumps corresponding to the motors, respectively, are provided, and a main control valve (MCV) for receiving a hydraulic oil from the hydraulic pumps to supply the hydraulic oil to a plurality of actuators is provided, so that efficient control is performed according to an operating load, an operating temperature, a supply flow rate, and the like to minimize power consumption of the motor, and thus electrical efficiency is improved to dramatically increase an operating time.

A hydraulic unit includes an oil tank, a hydraulic pump, a first return pipe, and a first heat exchanger. The oil tank stores a hydraulic oil. The hydraulic pump supplies the hydraulic oil in the oil tank to an actuator. The first return pipe returns the hydraulic oil from a flow path between a discharge port of the hydraulic pump and the actuator to the oil tank. The first heat exchanger causes a coolant to exchange heat with the hydraulic oil returning to the oil tank through the first return pipe.

A hydraulic circuit includes a prime mover that is configured to generate an oscillating flow of hydraulic fluid, and an actuator that is driven by the prime mover and configured to provide oscillating motion and to be connected to a load in each direction of the motion. The hydraulic circuit also includes a reclamation device that is disposed in the hydraulic circuit between the prime mover and the actuator. The reclamation device captures and stores a portion of hydraulic fluid displaced from the actuator during a transition between opposed motions, where the portion of hydraulic fluid corresponds to an amount of hydraulic fluid equal to a volume of fluid required to compensate for compression of fluid within the hydraulic circuit due to system pressure and load pressure. The stored fluid is used by the circuit in a subsequent motion.

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 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.