A hydraulic system for an agricultural system includes a hydraulic circuit and a bi-directional filter disposed on a bi-directional fluid line of the hydraulic circuit. The bi-directional filter includes a check valve fluid line having a check valve configured to block a fluid from flowing through the check valve fluid line in a first direction and to enable the fluid to flow through the check valve fluid line in a second direction, opposite the first direction, and a filter fluid line having a filter configured to enable the fluid to flow through the filter fluid line in the first direction and the second direction. The filter is configured to block particles that are greater than a threshold size from passing through the filter fluid line, and the filter fluid line is in a parallel flow configuration with respect to the check valve fluid line.

A hydraulic system includes: a cylinder in which an interior of a tube is divided by a piston into a first pressure chamber and a second pressure chamber; a first bidirectional pump connected to the first pressure chamber by a first supply/discharge line; a second bidirectional pump connected to the second pressure chamber by a second supply/discharge line and coupled to the first bidirectional pump in a manner enabling torque to be transmitted between the first and second bidirectional pumps; a relay line connecting the first and second bidirectional pumps such that a hydraulic liquid discharged from one of the first and second bidirectional pumps is introduced into the other of the first and second bidirectional pumps; and an electric motor that drives the first or second bidirectional pump. At least one of the first and second bidirectional pumps is a variable displacement pump whose delivery capacity per rotation is freely variable.

A hydraulic excavator is provided which can suppress the fuel consumption amount and improve the work efficiency by reducing the hydraulic pressure loss generated when a plurality of hydraulic actuators different in load are operated simultaneously. The hydraulic excavator includes a center bypass flow control valve that is arranged at the most downstream of a center bypass line and limits the flow rate of hydraulic fluid passing through the center bypass line in response to the operation amount of the second operation device in a case where a second operation device is operated, and a spool stroke limitation device that, in a case where a first operation device and the second operation device are operated simultaneously, limits the spool stroke amount of a second directional control valve in response to the operation amount of the first operation device in a state in which the spool stroke amount of a third directional control valve is controlled in response to the operation amount of the second operation device.

The electrohydrostatic actuator system according to the invention comprises a volume-variable and/or rotational-speed-variable hydro machine, which is driven by an electric motor, for providing a volume flow of a hydraulic fluid, and a main shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first main hydraulic line and a first main valve, is hydraulically connected to the hydro machine via a connection line. The actuator system according to the invention further comprises a secondary shaft which is movable by the hydraulic fluid and which has at least one first chamber, wherein the first chamber, with at least one first secondary hydraulic line and a first secondary valve, is hydraulically connected to the hydro machine via a connection line. Furthermore, according to the invention, a hydraulic accumulator is hydraulically connected to the first secondary hydraulic line in the area between the first chamber of the secondary shaft and the first secondary valve.

A hydraulic drive system includes a hydraulic pump, a boom-dedicated control valve, a turning-dedicated control valve, a boom-dedicated operation unit, a turning-dedicated operation unit, and a driving control unit. If an operating amount of the turning-dedicated operating portion where a concurrent operation is performed and a single operation is performed are the same, the driving control unit adjusts a turning driving command, that an opening area between the hydraulic pump and a turning motor where the concurrent operation is performed is less than the opening area between the hydraulic pump and the turning motor where the single operation is performed, the concurrent operation wherein the turning operation command is outputted from the turning-dedicated operation unit and a boom operation command is outputted from the boom-dedicated operation unit, the single operation wherein the turning operation command is outputted, but the boom operation command is not outputted from the boom-dedicated operation unit.

An auxiliary hydraulic manifold for connecting different implements to a work vehicle for hydraulic control may include a housing, a plurality of vehicle-side ports in the housing including a first vehicle-side port, and a plurality of implement-side ports in the housing including a first implement-side port fluidly coupled to the first vehicle-side port and a second implement-side port fluidly coupled to the first vehicle-side port. A number of the plurality of implement-side ports is greater than a number of the plurality of vehicle-side ports. Additionally, the auxiliary hydraulic manifold may include a pilot-operated check valve fluidly coupled between the first vehicle-side port and the first implement-side port.

To make it possible to control supply, discharge, and recycled flow rates independently of each other for the boom cylinder in a construction machine comprising first and second boom spool valves respectively connected to first and second hydraulic pumps. When the boom cylinder is contracted, the first boom spool valve is configured to control the recycled flow rate from head side oil chamber to rod side oil chamber, the second boom spool valve is configured to control the discharge flow rate from head side oil chamber to oil tank, and both first and second boom spool valves are configured not to supply pressure oil from first and second hydraulic pumps to the boom cylinder.

A forklift truck includes a carriage that moves up and down by a mast assembly in a multi-stage structure including an outer mast, a first inner mast accommodated in the outer mast, and a second inner mast accommodated in the first inner mast. The forklift truck includes a first lift cylinder configured to move the first inner mast up and down; a second lift cylinder configured to move the second inner mast up and down and having a pressure reception area less than a pressure reception area of the first lift cylinder. A first lift hydraulic line supplies hydraulic oil to the first lift cylinder. A second lift hydraulic line supplies hydraulic oil to the second lift cylinder. A pressure regulating valve is provided to increase a pressure of the hydraulic oil to a pressure capable of driving the second lift cylinder.

An agricultural machine includes a float cylinder interconnecting a header linkage system and a frame of the machine. A first rod side accumulator and a second rod side accumulator are both in fluid communication with a rod side fluid port of the float cylinder. A first accumulator control valve is positioned to control the first rod side accumulator, and is selectively controllable between an open position allowing fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder, and closed position blocking fluid communication between the first rod side accumulator and the rod side fluid port of the float cylinder. The system provides a slower first float response with the first accumulator control valve open, and a faster second float response with the first accumulator control valve closed.

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.