To provide a hydraulic drive system for a work machine capable of securing a favorable operability in the case where hydraulic fluid discharged from a hydraulic actuator is regenerated for driving other hydraulic actuator. The hydraulic drive system for a work machine includes: a regeneration line that connects a bottom-side hydraulic chamber of a hydraulic cylinder to a portion between a hydraulic pump and a second hydraulic actuator; a regeneration flow rate adjustment device that supplies at least part of the hydraulic fluid discharged from the bottom-side hydraulic chamber to a portion between the hydraulic pump and the second hydraulic actuator through the regeneration line; a differential pressure calculating section that reads a pressure in the bottom-side hydraulic chamber of the hydraulic cylinder detected by a first pressure sensor and a pressure between the hydraulic pump and the second hydraulic actuator detected by a second pressure sensor, and calculates a differential pressure, or a differential pressure sensor; and a control unit that controls the regeneration flow rate adjustment device such as to gradually increase the flow rate of the hydraulic fluid flowing through the regeneration line according to an increase in the differential pressure calculated by the differential pressure calculation section or in the differential pressure detected by the differential pressure sensor.

The present disclosure relates to variable recruitment actuator systems and related methods. In one embodiment, a variable recruitment actuator system may include a high-pressure fluid connection and a plurality of actuators. A variable recruitment actuator mechanism may selectively recruit a subset of the plurality of actuators based on a position of the variable recruitment actuator mechanism by selectively placing the subset of the plurality of actuators in fluid communication with the high-pressure fluid connection. A control system to control the position of the variable recruitment actuator mechanism may operate based on an input from a user.

A latching solenoid assembly is provided which includes a solenoid actuator. A housing is also provided which has an axial passage. An intermediate piston is moved by the solenoid actuator. A reaction member is also placed within the housing axial passage spring biased by a transfer spring from the intermediate piston. The housing has a latching port allowing pressure to latch the intermediate piston in position to set the force which is transmitted to the reaction member.

A work machine, preferably a mobile work machine, has an attachment device, in particular a trench cutter. The attachment device has at least two adjustable hydraulic motors for driving independent, individually controllable loads. The hydraulic supply of the adjustable hydraulic motors takes place by a hydraulic drive unit arranged externally from the attachment device, in particular by a drive unit of the work machine. The at least two adjustable hydraulic motors of the attachment device are connected to a constant pressure network provided by the hydraulic drive unit.

A control system and method for controlling the positioning of an adjustable deflector plate employed in a harvesting combine to adjust a side-to-side flow of crop residue to spreaders associated with the combine and the distribution thereby. The deflector plate is operably extendable into the flow of crop residue to redirect crop residue impinging the deflector plate. The deflector plate is adjusted based upon a comparison between the open/closed states of valves associated with the control system.

The hydraulic system according to the invention is a hydraulic system for controlling a stabilizer drive, in particular for controlling an angle of attack and/or a pivoting out and in of a stabilizer wing, preferably for ships. The hydraulic system according to the invention has a rotary vane motor that changes the angle of attack of the stabilizer wing and/or a hydraulic cylinder for pivoting the stabilizer wing out and in, along with a first hydraulic circuit. The first hydraulic circuit furthermore comprises a low-pressure circuit and a high-pressure circuit, a device for providing an admission pressure of the low-pressure circuit, and two anti-cavitation valves which separate the first low-pressure circuit from the first high-pressure circuit. The hydraulic system according to the invention is furthermore characterized in that a first hydraulic pump driven by an electric motor and having two connections is integrated in the high-pressure circuit and is hydraulically connected to the rotary vane motor and/or the hydraulic cylinder.

A hydraulic excavator 1 includes an engine 16, a main hydraulic pump 17 driven by the engine 16, a plurality of hydraulic actuators driven with pressure oil discharged from the main hydraulic pump 17, a plurality of flow rate control valves adapted to control the flow rate of pressure oil to be supplied from the main hydraulic pump 17 to the respective hydraulic actuators, a pilot hydraulic pump 18 adapted to supply pressure oil for driving the flow rate control valves, and a controller 15 configured to control the discharge flow rate of the pilot hydraulic pump 18. The controller 15 controls the discharge flow rate of the pilot hydraulic pump 18 such that it becomes equal to the sum of requested pilot flow rates determined in accordance with control commands for the respective flow rate control valves and a preset standby flow rate.

The present disclosure relates to variable recruitment actuator systems and related methods. In one embodiment, a variable recruitment actuator system may include a high-pressure fluid connection and a plurality of actuators. A variable recruitment actuator mechanism may selectively recruit a subset of the plurality of actuators based on a position of the variable recruitment actuator mechanism by selectively placing the subset of the plurality of actuators in fluid communication with the high-pressure fluid connection. A control system to control the position of the variable recruitment actuator mechanism may operate based on an input from a user.

An actuation pressure to actuate one or more hydraulic actuators may be determined based on a load on the one or more hydraulic actuators of a robotic device. Based on the determined actuation pressure, a pressure rail from among a set of pressure rails at respective pressures may be selected. One or more valves may connect the selected pressure rail to a metering valve. The hydraulic drive system may operate in a discrete mode in which the metering valve opens such that hydraulic fluid flows from the selected pressure rail through the metering valve to the one or more hydraulic actuators at approximately the supply pressure. Responsive to a control state of the robotic device, the hydraulic drive system may operate in a continuous mode in which the metering valve throttles the hydraulic fluid such that the supply pressure is reduced to the determined actuation pressure.

Systems and methods for control of multi-function hydraulic commands of a multi-function electrohydraulic system are provided. In one aspect, a system for hydraulic control includes a first function in fluid communication with a first electrohydraulic control valve and a second function in fluid communication with a second electrohydraulic control valve. The system includes a controller in communication with the first electrohydraulic control valve and the second electrohydraulic control valve. The controller can be configured to receive an input target command, determine an achievable function rate based on the input target command, where the achievable function rate maintains a proportional relationship between the input target command and the achievable function rate. The controller can also map the achievable function rate to an output command based on a predetermined relationship between the achievable function rates and the output commands and supply the output command to the first and second electrohydraulic valves.