A solenoid comprises first and second coils connected to an electrical power supply circuit. In a first mode of operation the power supply circuit is arranged to provide a current flowing in opposite directions through the respective first and second coils, e.g. to produce a self-heating effect. In a second mode of operation the power supply circuit is arranged to provide a current flowing in the same direction through the respective first and second coils, e.g. to generate a magnetic force. In some embodiments, the power supply circuit includes a bridge rectifier or full wave rectifier connected to a bi-directional current driver.

A hydraulic system for a work machine includes a tank to store an operation fluid, a hydraulic device to be operated by the operation fluid, a control valve to control the hydraulic device, a first fluid tube connecting the hydraulic device and the control valve, the first fluid tube being to supply the operation fluid from the control valve to the hydraulic device, a second fluid tube branching from the first fluid tube and connected to the tank, a switch valve provided to the second fluid tube, the switch valve being to control a flow rate of the operation fluid, and an oil cooler provided to the second fluid tube between the switch valve and the tank.

A work machine includes a mechanical arm and a hydraulic actuator coupled to the mechanical arm to move the arm between a first position and a second position. A valve is in fluid communication with the hydraulic actuator for supplying fluid to the hydraulic actuator. A pump is configured to discharge fluid to the valve. An engine is operatively connected to the pump. A coolant system is in thermal communication with the engine and includes a temperature sensor. A controller is in communication with the pump and the temperature sensor. The controller is configured to transmit a control signal to the pump to modify a flowrate of the pump and to adjust the flowrate of the pump in response to a signal from the temperature sensor that a temperature is at or above a set temperature value.

A work machine includes a mechanical arm and a hydraulic actuator coupled to the mechanical arm to move the arm between a first position and a second position. A valve is in fluid communication with the hydraulic actuator for supplying fluid to the hydraulic actuator. A pump is configured to discharge fluid to the valve. An engine is operatively connected to the pump. A coolant system is in thermal communication with the engine and includes a temperature sensor. A controller is in communication with the pump and the temperature sensor. The controller is configured to transmit a control signal to the pump to modify a flowrate of the pump and to adjust the flowrate of the pump in response to a signal from the temperature sensor that a temperature is at or above a set temperature value.

A hydraulic cooling system for a heavy-equipment machine, with the heavy-equipment machine including a frame supported on the ground by a ground-drive assembly, a cab extending upward from the frame, and an attachment tool for performing work. The hydraulic cooling system comprises a main housing and a cooling assembly housed at least partly within the main housing, with the cooling assembly being configured to reduce a temperature of hydraulic oil flowing through the hydraulic cooling system. The hydraulic cooling system further comprises an attachment assembly for attaching the main housing to the cab of the heavy-equipment machine. The main housing is configured to extend rearward from the cab.

Systems and methods for reducing the pressure of a first pressurized fluid, thereby reducing the temperature of the pressurized fluid, and utilization of the reduced-pressure and temperature fluid to cool a second fluid. Such an approach can enable a reduction in the size and weight of a hydraulic system, utilize waste energy in a system, and/or minimize electrical power requirements of a system, among other benefits.

A drive device includes a housing forming a sump. A pump and motor are mounted on a center section having a porting system and a pair of ports with check plugs disposed therein. A bypass arm is engaged to one end of a bypass shaft external to the housing and rotates the bypass shaft to selectively cause engagement fingers to move each check plug to an open position. A housing projection is contacted by the bypass arm to selectively limit rotation thereof. The axes of rotation of a swash plate trunnion shaft, a pump input shaft and a motor output shaft may all be disposed in a single plane. The input shaft is supported by a housing bearing and an opening in the center section and is restrained from axial movement by the bearing and a thrust surface on the center section.

The invention relates to a self-propelled ground milling machine, in particular a road cold milling machine, stabilizer or recycler, comprising a milling device for milling the ground at a milling depth, a machine frame supported by front and rear travel units, an internal combustion engine arranged in an engine compartment, a hydraulic system with at least two hydraulic pumps, a pump transfer gear and a hydraulic tank, and an operator platform.

The invention relates to a self-propelled ground milling machine, in particular a road cold milling machine, stabilizer or recycler, comprising a milling device for milling the ground at a milling depth, a machine frame supported by front and rear travel units, an internal combustion engine arranged in an engine compartment, a hydraulic system with at least two hydraulic pumps, a pump transfer gear and a hydraulic tank, and an operator platform.

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.