A travel control device is provided with hydraulic pumps of a variable capacity type that are driven by an engine; hydraulic motors that are driven by discharged oil from the hydraulic pumps; traveling devices that are rotation-driven by the hydraulic motors; a travel operation lever that is operated so as to instruct a traveling operation; a first control valve for generating a charged hydraulic pressure by adjusting the discharged oil from a charge pump and a second control valve for generating a capacity control hydraulic pressure in accordance with the operation of the travel operation lever. The first control valve is designed to pressure-adjust and generate a charged hydraulic pressure in accordance with the rotation speed of the engine, and the hydraulic pump is subjected to a variable capacity control process by a capacity control hydraulic pressure that is pressure-adjusted and generated by the second control valve.

A fluid pressure system includes an actuator, an operating valve, and a spool valve. The spool valve is connected to a pressure source and a tank by a pressure source line and a tank line, respectively, and connected to the actuator by a first movement line and a second movement line. The spool valve moves from a neutral position to a movement position by a moving amount corresponding to a pilot pressure outputted from the operating valve, the movement position being a position at which the spool valve allows the pressure source line to communicate with the first movement line and allows the second movement line to communicate with the tank line. A relief line branches off from the second movement line, and the relief line connects to a tank. A variable throttle valve is provided on the relief line.

A modular multi-pump system is provided. The modular multi-pump system may comprise a plurality of modular pump systems. A modular pump system may comprise a pump, at least one backpressure orifice, a pressure regulating valve (PRV), and a mix valve. The pump may receive and pump a fluid through the modular multi-pump system. The at least one backpressure orifice may set a desired fluid output pressure for the fluid flow. The pressure regulating valve may maintain modular pump system fluid output pressure in response to being in a balanced position, and may initiate fluid flow transition to the next modular pump system in response to being in a transition position. The mix valve may prevent fluid flow from the next modular pump system in response to being in a first position, and enable fluid flow from the next modular pump system in response to being in a second position.

A drum unloader may include a pump assembly, a motor, a plate, a piston-cylinder assembly, and a sensor. The motor drives the pump assembly. The plate is mounted to the pump assembly and includes an inlet to the pump assembly. The piston-cylinder assembly includes a housing, a piston, and a piston rod. The housing defines a bore. The piston is received within the bore and cooperates with the housing to define a first cavity and a second cavity. The piston rod is attached to and extends from the piston such that the piston rod extends through the first cavity. The piston rod is coupled to the pump assembly, the motor and the plate such that movement of the piston within the bore causes corresponding movement of the pump assembly, the motor and the plate relative to the housing. The sensor measures a pressure within the second cavity.

A refuse vehicle includes a chassis and a vehicle body. A variable displacement pump is positioned within the vehicle body and is configured to pump hydraulic fluid from a hydraulic fluid reservoir into a high pressure line of a hydraulic circuit. A lifting system on the vehicle includes at least one actuator in fluid communication with the variable displacement pump, which delivers pressurized hydraulic fluid from the hydraulic fluid reservoir to the actuator through the high pressure line to adjust a position of the actuator. A valve is positioned downstream of the variable displacement pump. In a first valve position, the valve restricts flow outward from the high pressure line. In a second valve position, the valve directs fluid from the high pressure line into a lower pressure line to reduce a hydraulic pressure within the high pressure line and adjust an output parameter of the variable displacement pump.

In one aspect, a system for controlling the supply of hydraulic fluid to an implement of a work vehicle may generally include a pump, a control valve coupled to the pump and first and second fluid lines provided in flow communication with output ports of the control valve. The system may also include a pressure control valve provided in flow communication with the second fluid line that is configured to regulate a fluid pressure of the hydraulic fluid being supplied to a hydraulic cylinder of the implement. Additionally, the system may include a bypass fluid line configured to provide a flow path for hydraulic fluid between the pump and the second fluid line that is independent of the control valve and a load sensing line configured to provide an indication of the fluid pressure of the hydraulic fluid being supplied to the hydraulic cylinder.

An online method for reconfiguring pressure and position sensors in a hydraulic system is disclosed. In one step, a sensor drift condition, a recalibration request, or an unisolated fault condition is detected. In another step, a system pressure sensor or another sensor, such as a load-sense pressure sensor, is verified as a trusted master reference sensor. Another step includes measuring and recording a first pressure reading at the master reference sensor and first voltage readings associated with first, second, third, and fourth pressure slave sensors at a first pump pressure set point. Another step includes, repeating the previous step at a second pump pressure set point. A new gain and offset for each of the first, second, third, and fourth pressure sensors can be calculated based on a comparison of the recoded first and second pressure readings and the recorded first and second voltage readings.

A drum unloader may include a pump assembly, a motor, a plate, a piston-cylinder assembly, and a sensor. The motor drives the pump assembly. The plate is mounted to the pump assembly and includes an inlet to the pump assembly. The piston-cylinder assembly includes a housing, a piston, and a piston rod. The housing defines a bore. The piston is received within the bore and cooperates with the housing to define a first cavity and a second cavity. The piston rod is attached to and extends from the piston such that the piston rod extends through the first cavity. The piston rod is coupled to the pump assembly, the motor and the plate such that movement of the piston within the bore causes corresponding movement of the pump assembly, the motor and the plate relative to the housing. The sensor measures a pressure within the second cavity.

According to an embodiment of the present disclosure, there is provided a hydraulic power unit, HPU, for providing a pressurised hydraulic fluid to a material testing apparatus, the HPU comprising: a reservoir for storing a hydraulic fluid; a pump for pumping the hydraulic fluid to an outlet connectable to the material testing apparatus; an alternating current, AC, electric motor arranged to drive the pump, wherein the electric motor is located within the reservoir; and an electrical inverter for providing an AC electrical supply to the electric motor, wherein the electrical inverter is arranged to control an operating point of the electric motor.

A refuse vehicle includes a chassis and a vehicle body. A variable displacement pump is positioned within the vehicle body and is configured to pump hydraulic fluid from a hydraulic fluid reservoir into a high pressure line of a hydraulic circuit. A lifting system on the vehicle includes at least one actuator in fluid communication with the variable displacement pump, which delivers pressurized hydraulic fluid from the hydraulic fluid reservoir to the actuator through the high pressure line to adjust a position of the actuator. A valve is positioned downstream of the variable displacement pump. In a first valve position, the valve restricts flow outward from the high pressure line. In a second valve position, the valve directs fluid from the high pressure line into a lower pressure line to reduce a hydraulic pressure within the high pressure line and adjust an output parameter of the variable displacement pump.