An electro-hydrostatic actuation system and a method for driving a hydraulic actuator, e.g. a hydraulic cylinder, are described, wherein the system comprising a leakage branch, and wherein preferably an additional pump is arranged. The system further comprises a source for providing hydraulic liquid; a high-pressure circuit to direct the hydraulic liquid to a hydraulic actuator, such as e.g. a hydraulic cylinder; a low-pressure circuit having several branches; a main pump for hydraulic liquid arranged in the high-pressure circuit, comprising a housing having a high-pressure section and a low-pressure section, separated by gap sealings, wherein the high-pressure section comprises a first outlet and a second outlet to provide the hydraulic liquid flow in the high-pressure circuit; and wherein the low- pressure section comprises a leakage outlet; an electric motor driving the main pump.

Actuator systems and methods of operation are disclosed. The systems include a hydraulic actuator having a primary piston having a piston head arranged within a housing defining retract and extend chambers on opposite sides of the piston head. A control element is configured to control a supply of pressure to each of the retract and extend chambers. An actuator valve is coupled to the housing and includes a secondary piston that is biased into the retract chamber in an open flow state and when the primary piston is in a fully retracted state the piston head urges the secondary piston into a closed flow state. The actuator valve defines a flow chamber where, in an open flow state, fluid can be passed through the flow chamber and in a closed flow state the fluid is prevented from passing through the flow chamber.

A control circuit for changing the angle of propeller blades includes a propeller control unit controlling a supply of oil to modify an angle of propeller blades, and a fixed-displacement pump providing the supply of oil from an engine oil return system to the propeller control unit. An oil cooling line extends between an outlet of the pump and the engine oil return system. The oil cooling line defines an oil leakage path leading to the engine oil return system for cooling the oil. A flow regulator between the pump and the propeller control unit is operable between an open position where oil is directed through the oil cooling line to the engine oil return system for cooling the oil, and a closed position blocking the oil cooling line and directing oil toward the propeller control unit to modify the angle of the propeller blades.

An actuator includes a housing, a first chamber inside the housing, a cylinder within the housing, and a second chamber within the housing. The cylinder fluidically isolates the first chamber from the second chamber. The actuator also includes a rod connected to the cylinder and extending through the second chamber and the housing. A shell is spaced apart from the housing and defines a fluid gap between the shell and the housing. The shell includes a shell inlet fluidically connected to the fluid gap and a shell outlet fluidically connected to the fluid gap.

There is provided a control module for a hydraulic system. The module comprises a tank and a plurality of valves. The tank is configured to store hydraulic fluid and is substantially cylindrical. The plurality of valves fluidly connect with the tank and are configured to control distribution of hydraulic fluid from the tank to one or more components of the system. The plurality of valves are spaced around a circumference of the tank. One or more passages fluidly connect the tank with at least one of the plurality of valves and/or a first of the plurality of valves with a second of the plurality of valves.

A vehicle includes a frame, at least one traction device coupled to the frame for facilitating movement of the vehicle, an implement coupled to the frame and configured to perform a work operation, a gearbox, a hydraulic system having a hydraulic reservoir, and an oil cooling system configured to cool the gearbox and the hydraulic system. The oil cooling system includes first and second circuits for a cooling oil, and a crossover circuit. The first circuit includes the gearbox and a first oil-to-air cooler configured to cool the cooling oil from the gearbox. The second circuit includes the hydraulic reservoir and a second oil-to-air cooler for cooling the cooling oil from the hydraulic reservoir. The crossover circuit includes the gearbox and the hydraulic reservoir and is configured to exchange the cooling oil between the gearbox and the hydraulic reservoir to provide heat transfer between the first and second circuits.

A vehicle includes a frame, at least one traction device coupled to the frame for facilitating movement of the vehicle, an implement coupled to the frame and configured to perform a work operation, a gearbox, a hydraulic system having a hydraulic reservoir, and an oil cooling system configured to cool the gearbox and the hydraulic system. The oil cooling system includes first and second circuits for a cooling oil, and a crossover circuit. The first circuit includes the gearbox and a first oil-to-air cooler configured to cool the cooling oil from the gearbox. The second circuit includes the hydraulic reservoir and a second oil-to-air cooler for cooling the cooling oil from the hydraulic reservoir. The crossover circuit includes the gearbox and the hydraulic reservoir and is configured to exchange the cooling oil between the gearbox and the hydraulic reservoir to provide heat transfer between the first and second circuits.

A work machine including a prime mover, an electric motor, an electric motor fluid circuit, a transmission fluid circuit, a hydraulic circuit, a cooling circuit, a pump, and a controller. The electric motor may supply a portion of power of the prime mover. The electric motor fluid circuit may be adapted to remove waste heat from the electric motor. The transmission fluid circuit may be adapted to lubricate a moving part of a transmission powered by the prime mover. The hydraulic circuit may be adapted to transmit power from the prime mover to a moving component of the work machine. The cooling circuit may be absorbing waste heat from one or more of the electric motor fluid circuit, the transmission fluid circuit, and the hydraulic circuit. The control may be adapted to control diversion of a portion of waste heat from the cooling circuit to a portion of the cab.

A work machine including a prime mover, an electric motor, an electric motor fluid circuit, a transmission fluid circuit, a hydraulic circuit, a cooling circuit, a pump, and a controller. The electric motor may supply a portion of power of the prime mover. The electric motor fluid circuit may be adapted to remove waste heat from the electric motor. The transmission fluid circuit may be adapted to lubricate a moving part of a transmission powered by the prime mover. The hydraulic circuit may be adapted to transmit power from the prime mover to a moving component of the work machine. The cooling circuit may be absorbing waste heat from one or more of the electric motor fluid circuit, the transmission fluid circuit, and the hydraulic circuit. The control may be adapted to control diversion of a portion of waste heat from the cooling circuit to a portion of the cab.

An unmanned vehicle control system includes: a determination unit that determines whether or not to output a heating request for a hydraulic oil based on hydraulic oil data supplied to a hydraulic actuator disposed in an unmanned vehicle and operated by the hydraulic oil; a vehicle receiver that receives a heating command for the hydraulic oil generated based on the heating request; and a heating processor that executes a heating process of the hydraulic oil based on the heating command.