Hydraulic systems for a power machine
AssigneeDoosan Bobcat North America, Inc.
InventorsNicolas Galès, Arnaud Guinee
Life of this patent
Estimating the term…
Abstract
A hydraulic system for a power machine can include a hydrostatic drive motor, a hydrostatic drive pump that is in communication with the hydrostatic drive motor via a hydrostatic drive circuit. A drain case can include one or more of the hydrostatic drive motor or the hydrostatic drive pump. A venturi device can include a main flow inlet in communication with the hydrostatic drive circuit, a main flow outlet, and a suction inlet in communication with the drain case. The hydraulic system can further include a heat exchanger, a tank, and an assist pump that includes an assist pump inlet in communication with the main flow outlet of the venturi device and an assist pump outlet in communication with the heat exchanger.
Claims19
A hydraulic system for a power machine, the hydraulic system comprising:
- a hydrostatic drive motor;
- a hydrostatic drive pump in communication with the hydrostatic drive motor via a hydrostatic drive circuit;
- a drain case that includes one or more of the hydrostatic drive motor or the hydrostatic drive pump;
- a venturi device that includes a main flow inlet in communication with the hydrostatic drive circuit, a main flow outlet, and a suction inlet in communication with the drain case, the venturi device being configured to provide suction to the drain case via the suction inlet during flow of fluid from the main flow inlet to the main flow outlet;
- a heat exchanger;
- a tank;
- and
- an assist pump that includes an assist pump inlet in communication with the main flow outlet of the venturi device and an assist pump outlet in communication with the heat exchanger, the assist pump being configured to receive flow from the main flow outlet of the venturi device and provide pressurized flow to the tank via the heat exchanger.
A power machine comprising:
- a power source;
- a hydrostatic drive system that includes:
- a hydrostatic drive circuit;
- a drive pump powered by the power source;
- a drive motor powered by the drive pump via the hydrostatic drive circuit;
- and
- a drain case that includes the drive motor;
- a venturi device that includes a main flow inlet, a main flow outlet, and a suction inlet in communication with the drain case;
- a heat exchanger;
- a tank;
- and
- an assist pump that is powered by the power source and includes:
- an assist pump inlet supplied by the main flow outlet of the venturi device, and an assist pump outlet in communication with the heat exchanger;
- the hydrostatic drive system being configured to supply flow to the main flow inlet of the venturi device, to draw fluid from the drain case via the suction inlet of the venturi device;
- and
- the assist pump being configured to route the fluid drawn from the drain case to the tank, via the heat exchanger.
A method of operating a power machine, the method comprising:
- operating a hydrostatic drive pump of the power machine to provide pressurized flow of fluid within a hydrostatic drive circuit;
- routing a portion of the fluid from the hydrostatic drive circuit to a main flow inlet of a venturi device, to generate suction at a suction inlet of the venturi device and thereby induce fluid from a drain case of the hydrostatic drive circuit to flow from a main flow outlet of the venturi device;
- and
- using an assist pump, pressurizing the flow from the main flow outlet of the venturi device to flow through a heat exchanger to tank.
Dependencies are inferred from the claim text.