A hydraulic elevator may comprise a bidirectional pump that controls up and down motion of an elevator car. A VVVF drive may cause the bidirectional pump to provide working fluid in a controlled manner to a hydraulic jack that supports the elevator car. A control valve may be disposed between the bidirectional pump and the hydraulic jack so that the control valve can be closed when the elevator car needs to be held in place. To avoid pressure waves that propagate when the control valve is opened with disparate pressures on the pump and jack sides of the control valve, the bidirectional pump may adjust the pressure on the pump side of the closed control valve to the pressure on the jack side of the control valve before the control valve is opened.

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.

The invention relates to a system for a work machine. The power system comprises a power-split continuously variable transmission for propulsion of the work machine and a hydraulic system for work hydraulics. The power-split continuously variable transmission has a hydrostatic branch and a mechanical branch. The hydrostatic branch comprises a first hydraulic machine and a second hydraulic machine. The hydrostatic branch comprises a first control valve fluidly connected to the first hydraulic machine and to the second hydraulic machine for controlling the flow of hydraulic fluid between the first hydraulic machine and the second hydraulic machine. The hydraulic system comprises at least one hydraulic actuator fluidly connected to a first port of the first hydraulic machine, and a second control valve for controlling the flow of hydraulic fluid to said at least one hydraulic actuator.

A robotic device may traverse a path in a direction of locomotion. Sensor data indicative of one or more physical features of the environment in the direction of locomotion may be received. The implementation may further involve determining that traversing the path involves traversing the one or more physical features of the environment. Based on the sensor data indicative of the one or more physical features of the environment in the direction of locomotion, a hydraulic pressure to supply to the one or more hydraulic actuators to traverse the one or more physical features of the environment may be predicted. Before traversing the one or more physical features of the environment, the hydraulic drive system may adjust pressure of supplied hydraulic fluid from the first pressure to the predicted hydraulic pressure.

A hydraulic power system for a downhole device, including a first motor, a first hydraulic pump, a second hydraulic pump, a first main oil circuit, a second main oil circuit, a switching control module and a first execution module. The first motor has a first output shaft which drives the first hydraulic pump and has an oil outlet connected to an input end of the first main oil circuit and a second output shaft which drives the second hydraulic pump and has an oil outlet connected to an input end of the second main oil circuit; the first execution module is connected to an output end of the first main oil circuit; displacement of the first hydraulic pump is smaller than that of the second hydraulic pump; and the switching control module is connected between the first main oil circuit and the second main oil circuit.

A transmission system includes a transmission assembly having clutches to transmit power from an input shaft to an output shaft at a plurality of gear ratios. A traction motor drives the input shaft and propels the work vehicle, while a controller controls operation of the transmission assembly and the traction motor. A hydraulic circuit controls actuation of the clutches responsive to commands from the controller. The hydraulic circuit includes a hydraulic pump driven by the traction motor, an accumulator connected to the hydraulic pump and that holds hydraulic fluid therein under pressure, and an unloading valve positioned in a secondary fluid path running from an outlet of the hydraulic pump to a sump. The unloading valve operates in a closed state to direct hydraulic fluid from the hydraulic pump to the accumulator and operates in an open state to direct hydraulic fluid from the hydraulic pump to the sump.

A hydraulic pressurizing medium supply assembly having a hydro machine for supplying pressurizing medium of at least one hydraulic consumer, includes a hydraulic control block for controlling the at least one consumer, a first control module, and a second control module. The control block, by way of the first control module, is able to be controlled by at least one actuating signal. A data interface is included between the control modules. The first control module, by way of the data interface, as a further actuating signal transfers to the second control module as input variable/variables a nominal outlet pressure for the hydro machine and/or a nominal delivery volume for the hydro machine. The second control module by way of the nominal outlet pressure and/or by way of the nominal delivery volume controls an adjusting mechanism of the hydro machine by way of a valve actuating signal.

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.

A robotic device may traverse a path in a direction of locomotion. Sensor data indicative of one or more physical features of the environment in the direction of locomotion may be received. The implementation may further involve determining that traversing the path involves traversing the one or more physical features of the environment. Based on the sensor data indicative of the one or more physical features of the environment in the direction of locomotion, a hydraulic pressure to supply to the one or more hydraulic actuators to traverse the one or more physical features of the environment may be predicted. Before traversing the one or more physical features of the environment, the hydraulic drive system may adjust pressure of supplied hydraulic fluid from the first pressure to the predicted hydraulic pressure.

A hydraulic pressurizing medium supply assembly having a hydro machine for supplying pressurizing medium of at least one hydraulic consumer, includes a hydraulic control block for controlling the at least one consumer, a first control module, and a second control module. The control block, by way of the first control module, is able to be controlled by at least one actuating signal. A data interface is included between the control modules. The first control module, by way of the data interface, as a further actuating signal transfers to the second control module as input variable/variables a nominal outlet pressure for the hydro machine and/or a nominal delivery volume for the hydro machine. The second control module by way of the nominal outlet pressure and/or by way of the nominal delivery volume controls an adjusting mechanism of the hydro machine by way of a valve actuating signal.