A system for automatically coordinating a direction of travel with a position of a turret rotatably mounted on an undercarriage of a hydraulic machine including a hydraulic transmission circuit for connecting a main pump to a bi-directional hydraulic travel motor. The circuit includes a travel control distributor able to vary a driving direction of the motor. The system includes a second hydraulic circuit disposed downstream of a pilot pump providing a pilot pressure. The second circuit includes: a valve controller for controlling a direction of travel, activatable by the operator and able to switch the control distributor by sending different command signals; and a reversing valve, interposed between the valve controller and the control distributor. The system further includes a coordination circuit able to switch or maintain the reversing valve according to the position of the turret and to the command signals.

A hydraulic system and method of controlling such on a machine is disclosed. The hydraulic system may comprise a primary hydraulic circuit that includes a first load sense controlled pump, a secondary hydraulic circuit that includes a second load sense controlled pump, a flow sharing valve, and a load sense arrangement. The load sense arrangement may include a main resolver configured to select a higher pressure signal between the primary and secondary hydraulic circuits, and a load sense valve having an open position at which pressure signal flow between the primary hydraulic circuit and the main resolver is allowed, and a closed position at which pressure signal flow between the primary hydraulic circuit and the main resolver is blocked. In an embodiment, when the load sense valve is in the closed position, the second load sense controlled pump may be controlled only by the secondary hydraulic circuit.

A hydraulic pump radiant noise reduction method for a forklift or other work machine is disclosed. The method includes initiating a noise control algorithm that is enabled during periods when the displacement of the hydraulic pump remains in the zero displacement position and an operator is not demanding flow from any of the hydraulic branch circuits. When the noise control algorithm is enabled, the control valve assembly associated with the hydraulic branch circuit having the lowest hydraulic fluid pressure in relation to the hydraulic fluid pressures of all other hydraulic branch circuits is opened while the remaining control valve assemblies are in held or placed in a closed position. In an alternative embodiment, a drain valve assembly is provided that is opened when the noise control algorithm is activated.

A lift device includes a hydraulic actuator configured to move an implement relative to a chassis, an implement circuit including a first pump coupled to the hydraulic actuator, a charge circuit including a second pump configured to selectively provide a flow of pressurized fluid to the implement circuit, a valve assembly fluidly coupled to the implement circuit and the charge circuit, and processing circuitry. The processing circuitry is configured to: in a first mode of operation, control the valve assembly to direct the flow of pressurized fluid to the charge circuit; in a second mode of operation, control the valve assembly to divert the flow of pressurized fluid to the implement circuit; and reconfigure the lift device between the first mode of operation and the second mode of operation in response to a command for the hydraulic actuator to at least one of move or reconfigure the implement.

In a lowering operation of a boom, the amount of operation of a control lever is detected by a pressure sensor and input to a controller. Based on the input operation amount, the controller obtains a target flow rate Q.sub.0 of return oil discharged from a boom cylinder, calculates a deviation Q between the target flow rate Q.sub.0 and an actual flow rate Q obtained from an actual rotation speed N of an electric motor acquired by a rotation speed sensor, calculates a signal Sm for controlling the opening area of a proportional solenoid valve in a manner allowing hydraulic fluid to flow to a control valve in just as much as Q, and controls an operation pilot pressure of the control valve supplied from a sub-pump in accordance with the signal Sm so that the hydraulic fluid will flow to the control valve exactly in the amount of Q.

A fluid pump for a linear actuator is provided. The pump causes a rod in the actuator to extend or retract by controlling the flow of fluid to and from portions of a fluid chamber on either side of a piston disposed within the fluid chamber and supporting the rod. The pump includes a valve structure that enables the pump to redistribute fluid obtained from one portion of the fluid chamber on one side of the piston to the other portion of the fluid chamber on the other side of the piston without first returning the fluid to a fluid reservoir thereby increasing the efficiency of the pump.

A working machine control system includes: a split-flow fluid pressure pump configured to discharge a working fluid from a first discharge port and a second discharge port; a communication switching valve configured to be switched by a switch signal when any one of a first operation valve and a second operation valve is switched so as to allow a first neutral passage and a second neutral passage to communicate with each other; a neutral cut valve configured to be switched by the switch signal so as to block communication between a tank and one of the first neutral passage and the second neutral passage for the first operation valve or the second operation valve that is not switched; and a discharge flow rate adjusting device configured to adjust the fluid pressure pump so as to reduce a discharge flow rate thereof when the switch signal is inputted from any one of the first operation valve and the second operation valve.

A method for grouping hydraulic functions associated with an agricultural implement includes accessing parameter data associated with hydraulic fluid used to drive a plurality of hydraulic functions of the implement, the hydraulic fluid being supplied from one of at least two pumps. The method also includes determining delivery pump pressures for the pumps for each of a plurality of different pump/function combinations based at least in part on the hydraulic parameter data and determining a power parameter requirement for the pumps for each of the different pump/function combinations based at least in part on the delivery pump pressures. In addition, the method includes selecting a desired pump/function combination based at least in part on the power parameter requirement, and controlling an operation of a plurality of switching valves such that the hydraulic fluid is supplied for driving the hydraulic functions in accordance with the desired pump/function combination.