The invention relates to a hydraulic system for a work machine. The system comprising: a main hydraulic machine connected to an output shaft of an engine of the work machine for providing power to working hydraulics of the work machine; a main pressure line connecting the main hydraulic machine to the working hydraulics; a support hydraulic machine connected to the output shaft; a hydraulic accumulator; a discharge valve connected between the accumulator and an input side of the support hydraulic machine; a charge valve connected between an output side of the support hydraulic machine and the hydraulic accumulator to selectively allow a flow from the support hydraulic machine to the hydraulic accumulator; a flow support valve connected between the output side of the support hydraulic machine and the main pressure line to selectively allow a flow from the support hydraulic machine to the main pressure line; and a hydraulic tank connected to the input side of the support hydraulic machine.

A fluid pressure circuit includes a directional switching valve arranged between a fixed displacement pump and a fluid pressure actuator and configured to switch a flow passage for a pressurized fluid, an accumulator arranged in a branch flow passage branched from a connection flow passage that connects the fluid pressure actuator and the directional switching valve, an accumulator flow control valve arranged between the connection flow passage and the accumulator, and a pump flow control valve arranged between the fluid pressure actuator and the fixed displacement pump and configured to variably divert a flow rate of the pressurized fluid discharged from the fixed displacement pump into a first system including the tank and a second system including the fluid pressure actuator.

A marine hydraulic system and method of use for reducing cyclic loading of the pump(s) and motor(s) and an amount of accumulator storage required in a hydraulic system. A closed loop logic controller comprising at least one control algorithm for each pump/motor pair utilized in a single hydraulic system is utilized to reduce load fluctuations on the motors, allow the use of common pressure compensated, variable displacement (VDH) pumps, reduce the number and/or volume of system accumulators and equalize wear throughout the system.

A marine hydraulic system and method of use for reducing cyclic loading of the pump(s) and motor(s) and an amount of accumulator storage required in a hydraulic system. A closed loop logic controller comprising at least one control algorithm for each pump/motor pair utilized in a single hydraulic system is utilized to reduce load fluctuations on the motors, allow the use of common pressure compensated, variable displacement (VDH) pumps, reduce the number and/or volume of system accumulators and equalize wear throughout the system.

A hydraulic system includes: a travel motor; travel pump connected to the travel motor, the travel pump driven by an engine; a work pump that sucks hydraulic oil from a tank through a suction line, and supplies the oil to a work hydraulic actuator through a delivery line, the work pump driven by the engine; a switching valve connected to the delivery line, and connected to a part of the suction line downstream of the check valve; and an accumulator connected to the switching valve. The switching valve switches between a neutral position in which the switching valve blocks a pressure accumulation line, a pressure release line, and the relay line, the pressure accumulation position in which the switching valve wherein the pressure accumulation line communicates with the relay line, a pressure release position in which the switching valve brings the relay line into communication with the pressure release line.

A hydraulic system includes: a travel motor; travel pump connected to the travel motor, the travel pump driven by an engine; a work pump that sucks hydraulic oil from a tank through a suction line, and supplies the oil to a work hydraulic actuator through a delivery line, the work pump driven by the engine; a switching valve connected to the delivery line, and connected to a part of the suction line downstream of the check valve; and an accumulator connected to the switching valve. The switching valve switches between a neutral position in which the switching valve blocks a pressure accumulation line, a pressure release line, and the relay line, the pressure accumulation position in which the switching valve wherein the pressure accumulation line communicates with the relay line, a pressure release position in which the switching valve brings the relay line into communication with the pressure release line.

An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

An example valve assembly includes a housing having an accumulator fluid passage configured to be fluidly coupled to an accumulator, a supply fluid cavity configured to be fluidly coupled to a source of fluid, a reservoir fluid cavity configured to be fluidly coupled to a reservoir of fluid, a head fluid cavity configured to be fluidly coupled to a head-side chamber of a hydraulic actuator, and a rod fluid cavity configured to be fluidly coupled to a rod-side chamber of the hydraulic actuator; a main spool that is axially-movable within the housing; and a balancing spool that is axially-movable within the housing based on an axial position of the main spool.

A device for maintaining a hydraulic supply of a utility vehicle includes a hydraulic pump, which is adjustable in terms of its delivery volume via a pressure control inlet, for feeding hydraulic fluid to a hydraulic circuit, a pressure accumulator that can be charged from the hydraulic circuit via a check valve, a pressure connection between the hydraulic circuit and the pressure control inlet of the hydraulic pump being producible via a sensor line by means of a charging valve, and a supply connection between the pressure accumulator and the hydraulic circuit being producible by means of a discharging valve, by virtue of the check valve being bypassed.

A hydraulic system for a cyclically operating shaping machine includes at least one hydraulic drive unit for cyclically driving a component of the shaping machine at a start time; at least one pump; and at least one hydraulic accumulator which can be discharged for driving the at least one hydraulic drive unit and which can be charged up by operation of the at least one pump. An open-loop or closed-loop control unit is also provided for control of the at least one pump. The open-loop or closed-loop control unit is adapted to operate the at least one pump continuously until the start time of the at least one hydraulic drive unit to charge up the at least one hydraulic accumulator until the start time of the hydraulic drive unit.