Propel system with active pump displacement control for balancing propel pump pressures in agricultural vehicles

Patent metadata

Field	Value
Publication number	US-10801617-B2
Application number	US-201815862986-A
Country	US
Kind code	B2
Filing date	Jan 5, 2018
Priority date	Jan 5, 2018
Publication date	Oct 13, 2020
Grant date	Oct 13, 2020

Abstract

A propel system of an agricultural vehicle has an active pump displacement control system for equalizing or balancing pressure output of hydrostatic pumps of a tandem pump propel arrangement. The active pump displacement control system may include a pressure sensor(s) for determining output pressure of hydrostatic pumps and use the output pressure values within a feedback loop to provide coil input values of coils that control displacement of the hydrostatic pumps so that the pressure outputted by the hydrostatic pumps can be equalized in real-time while on the go during use of the agricultural vehicle.

First claim

We claim:

1. A propel system with active pump displacement control for balancing propel pump pressures in an agricultural vehicle with wheels that can be rotated to propel the agricultural vehicle, the propel system comprising:
a hydrostatic drive system configured to rotate the wheels with hydraulic power to propel the agricultural vehicle, the hydrostatic drive system including,
multiple hydraulic wheel motors arranged to rotate the wheels of the agricultural vehicle;
a hydrostatic pump system configured to selectively deliver hydraulic oil to the wheel motors for controlling rotation of the wheels of the agricultural vehicle, the hydrostatic pump system including,
a first hydrostatic pump with variable displacement configured to deliver hydraulic oil to the wheel motors for controlling rotation of the wheels of the agricultural vehicle;
a second hydrostatic pump with variable displacement configured to deliver hydraulic oil to the wheel motors for controlling rotation of the wheels of the agricultural vehicle; and
a hydraulic distribution manifold arranged between the wheel motors and the first and second hydrostatic pumps, wherein the hydraulic distribution manifold is configured to receive hydraulic oil from each of the first and second hydrostatic pumps and deliver the hydraulic oil to the wheel motors; and

an active pump displacement control system including:
at least one sensor disposed between the first and second hydrostatic pumps and the hydraulic distribution manifold and configured to detect the output pressures of the first and second hydrostatic pumps;
a controller operatively connected to the at least one sensor and the first and second hydrostatic pumps, the controller adjusting displacement of the first and second hydrostatic pumps in response to output pressures of the first and second hydrostatic pumps detected by the at least one sensor to attenuate differences between the output pressures of the first and second hydrostatic pumps.

2. The propel system of claim 1 , wherein
when the active pump displacement control system determines that a pump pressure difference value between the output pressures of the first and second hydrostatic pumps is outside of a target range, the controller adjusts displacement of at least one of the first and second hydrostatic pumps to reduce the difference between the output pressures of the first and second hydrostatic pumps.

3. The propel system of claim 2 , wherein the at least one sensor is a pressure transducer.

4. The propel system of claim 3 , wherein the pressure transducer is a delta pressure transducer that communicates with each of the first and second hydrostatic pumps and is configured to detect a pressure differential between the first and second hydrostatic pumps.

5. The propel system of claim 1 , wherein the at least one sensor includes,
a first pressure transducer arranged for detecting an output pressure of the first hydrostatic pump; and
a second pressure transducer arranged for detecting an output pressure of the second hydrostatic pump.

6. The propel system of claim 1 , wherein the controller adjusts displacement of the first and second hydrostatic pumps to be within a pressure differential target range.

7. The propel system of claim 6 , wherein the first hydrostatic pump includes a first coil that is selectively energized to control the displacement of the first hydrostatic pump and the second hydrostatic pump includes a second coil that is selectively energized to control displacement of the second hydrostatic pump.

8. The propel system of claim 7 , wherein the controller is operatively connected to each of the first and second coils and selectively energizes ones of the first and second coils to control displacement of at least one of the first and second hydrostatic pumps to adjust the output pressures of in a corresponding one of the first and second hydrostatic pumps.

9. The propel system of claim 8 , wherein the controller selectively energizes one of the first and second coils to increase displacement of a lower pressure one of the first and second hydrostatic pumps.

10. The propel system of claim 8 , wherein the controller selectively energizes one of the first and second coils to decrease displacement of a greater pressure one of the first and second hydrostatic pumps.

11. The propel system of claim 8 , wherein the controller selectively energizes each of the first and second coils to simultaneously,
increase displacement of a lower pressure one of the first and second hydrostatic pumps; and
decrease displacement of a greater pressure one of the first and second hydrostatic pumps.

12. A propel system with active pump displacement control for balancing propel pump pressures in an agricultural vehicle, the propel system comprising:
multiple hydraulic wheel motors arranged to rotate wheels of the agricultural vehicle to propel the agricultural vehicle;
a tandem propel pump arrangement configured to selectively deliver hydraulic oil to the wheel motors for controlling rotation of the wheels of the agricultural vehicle, the tandem propel pump arrangement including:
a first hydrostatic propel pump with variable displacement and configured to deliver pressurized hydraulic oil at a variable pressure at a first pump output circuit pressure;
a second hydrostatic propel pump with variable displacement and configured to deliver pressurized hydraulic oil at a variable pressure at a second pump output circuit pressure; and
a hydraulic distribution manifold arranged between the wheel motors and the first and second hydrostatic pumps, wherein the hydraulic distribution manifold is configured to receive hydraulic oil from each of the first and second hydrostatic pumps and deliver the hydraulic oil to the wheel motors;

an active pump displacement control system, including:
at least one sensor disposed between the first and second hydrostatic pumps and the hydraulic distribution manifold and configured to detect the first and second pump output circuit pressures; and
a propel controller operably communicating with the at least one sensor and each of the first and second hydrostatic propel pumps and configured to adjust displacement of at least one of the first and second hydrostatic propel pumps in response to the first and second pump output circuit pressures detected by the at least one sensors to attenuate a difference between the first and second pump output circuit pressures.

13. The propel system of claim 12 , wherein the at least one sensor is a delta pressure transducer that communicates with each of the first and second hydrostatic pumps and is configured to detect a pressure differential between the first and second hydrostatic pumps.

14. The propel system of claim 12 , wherein the at least one sensor includes,
a first pressure transducer arranged for detecting the first pump output circuit pressure; and
a second pressure transducer arranged for detecting the second pump output circuit pressure.

15. The propel system of claim 12 , wherein the first hydrostatic pump includes a first coil that is selectively energized to control the displacement of the first hydrostatic pump and the second hydrostatic pump includes a second coil that is selectively energized to control displacement of the second hydrostatic pump; and
wherein the propel controller is operatively connected to each of the first and second coils and selectively energizes ones of the first and second coils to control displacement of at least one of the first and second hydrostatic pumps to attenuate differences between the first and second pump output circuit

Assignees

• Cnh Ind America Llc

Inventors

• Tollefsrud Aaron
• Connolly Daniel
• Keppers James
• Meyer Peter

Classifications

• F16H61/431

  Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves · CPC title

• F16H39/02

  with liquid motors at a distance from liquid pumps · CPC title

• F15B2211/20546

  variable capacity · CPC title

• B60Y2200/22

  Agricultural vehicles · CPC title

• B60K7/0015 Primary

  the motor being hydraulic · CPC title