Drive system having slip control

• US 20060211535A1
• Filed: 03/21/2005
• Published: 09/21/2006
• Est. Priority Date: 03/21/2005
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Casey, Kent A.
• Granted Patent: US 7,452,306 B2
• Time in Patent Office: Days
• US Class Current: 477/3
• CPC Class Codes: B60K 17/356 having fluid or electric motor, for driving one or more wheels disposition of motor in, or adjacent to, traction wheel B60K7/00
• CPC Class Codes: B60K 23/04 for differential gearing
• CPC Class Codes: B60K 28/16 responsive to, or preventing, skidding of wheels brake control systems for vehicle drive stability B60T8/1755; arrangements responsive to a speed condition for adjusting wheel braking force B60T8/32; control of vehicle driving stability otherwise than by controlling the propulsion unit only B60W30/02; preventing wheel slippage by reducing power in rail vehicles B61C15/00
• CPC Class Codes: B60T 8/4809 Traction control, stability control, using both the wheel brakes and other automatic braking systems
• CPC Class Codes: B60Y 2200/41 Construction vehicles, e.g. graders, excavators

Abstract

A drive system for a work machine is disclosed. The drive system has at least one driven traction device and a transmission operatively connected to the at least one driven traction device. The transmission is configured to drive the at least one driven traction device. The drive system further has a controller configured to determine a ground tractive capacity associated with the at least one driven traction device and to limit an amount of torque transmitted from the transmission to the at least one driven traction device when the amount of torque to be transmitted will exceed the ground tractive capacity.

Claims

1. A drive system for a work machine, the drive system comprising:

at least one driven traction device;

a transmission operatively connected to the at least one driven traction device and configured to drive the at least one driven traction device; and

a controller configured to determine a ground tractive capacity associated with the at least one driven traction device and to limit an amount of torque transmitted from the transmission to the at least one driven traction device when the amount of torque to be transmitted will exceed the ground tractive capacity.

2. The drive system of claim 1, wherein the transmission includes an electric motor.

3. The drive system of claim 1, wherein the transmission includes a hydraulic motor.

4. The drive system of claim 1, wherein the transmission includes a mechanical transmission.

5. The drive system of claim 1, further including a power source configured to supply power to the transmission, wherein the transmitted torque is limited by limiting an output of the power source.

6. The drive system of claim 1, wherein the transmitted torque is limited by changing operation of the transmission.

7. The drive system of claim 1, further including a braking mechanism associated with the at least one driven traction device, wherein the transmitted torque is limited by actuating the braking mechanism.

8. The drive system of claim 1, wherein the ground tractive capacity is determined as a function of a loading condition of the work machine

9. The drive system of claim 8, wherein the loading condition of the work machine includes a load on a work implement of the work machine.

10. The drive system of claim 9, wherein the loading condition of the work machine further includes a distribution of the load on the work machine.

11. The drive system of claim 9, wherein the loading condition of the work machine further includes an amount of fluid in a tank of the work machine.

12. The drive system of claim 1, wherein:

the controller includes a memory having a value stored therein that is indicative of a coefficient of friction between the at least one driven traction device and a ground surface; and

the ground tractive capacity is determined as a function of the stored value.

13. The drive system of claim 12, wherein the stored value is automatically updated in response to torque transmitted to the at least one traction device causing the at least one driven traction device to slip.

14. The drive system of claim 12, wherein the stored value is automatically updated in response to a location of the work machine.

15. The drive system of claim 1, wherein:

the at least one driven traction device is a first driven traction device,

the drive system further includes a second driven traction device;

the transmission is operatively connected to the second traction device and configured to drive the second driven traction device; and

the controller is configured to limit a total amount of torque transmitted from the transmission to the first and second driven traction devices to the sum of a design limit of the second driven traction device and a ground tractive capacity associated with the first driven traction device.

16. A method of operating a drive system of a work machine having at least one driven traction device, the method including:

determining a ground tractive capacity associated with the at least one driven traction device; and

limiting an amount of torque transferred to the at least one driven traction device when the amount of torque to be transmitted will exceed the determined ground tractive capacity.

17. The method of claim 16, wherein:

the work machine includes a transmission operably connected to a power source;

the transmission is configured to transmit torque to the at least one driven traction device; and

the amount of torque transferred is limited by limiting an output of the power source.

18. The method of claim 16, wherein:

the work machine includes a transmission operably connected to a power source;

the transmission is configured to transmit torque to the at least one driven traction device; and

the amount of torque transferred is limited by changing operation of the transmission.

19. The method of claim 16, wherein:

the work machine includes a braking mechanism associated with the at least one driven traction device; and

the amount of torque transferred is limited by actuating the braking mechanism.

20. The method of claim 16, wherein determining a ground tractive capacity includes determining a load on the work machine

21. The method of claim 20, wherein determining a load further includes determining a distribution of a load on the work machine.

22. The method of claim 21, wherein determining a load further includes determining an amount of fluid in a tank of the work machine.

23. The method of claim 20, wherein determining a ground tractive capacity further includes referencing a value indicative of a coefficient of friction between the at least one driven traction device and a ground surface.

24. The method of claim 23, further including automatically updating the value in response to the amount of torque transmitted to the at least one traction device causing the at least one driven traction device to slip.

25. The method of claim 23, further including automatically updating the value in response to a location of the work machine.

26. The method of claim 16, wherein:

the at least one driven traction device is a first driven traction device;

the work machine includes a second driven traction device; and

the method further includes;

limiting a total amount of torque transmitted from the transmission to the first and second driven traction devices to the sum of a design limit of the second driven traction device and a ground tractive capacity associated with the first driven traction device at least one

27. A work machine, comprising:

a power source configured to produce a power output;

at least one driven traction device;

a transmission operably connected to the power source and configured to drive the at least one driven traction device; and

a controller configured to determine a ground tractive capacity associated with the at least one driven traction device and to limit an amount of torque transmitted from the transmission to the at least one driven traction device when the amount of torque to be transmitted will exceed the current ground tractive capacity.

28. The work machine of claim 27, wherein the transmission includes at least one of an electric motor, a hydraulic motor, and a mechanical transmission.

29. The work machine of claim 27, further including a braking mechanism associated with the at least one driven traction device, wherein the transmitted torque is limited by at least one of limiting an output of the power source, changing operation of the transmission, and actuating the braking mechanism.

30. The work machine of claim 27, wherein:

the ground force tractive capacity is determined as a function of a loading condition of the work machine;

the controller includes a memory having a value stored therein that is indicative of a coefficient of friction between the at least one driven traction device and a ground surface; and

the ground tractive capacity is determined as a function of the stored value.

31. The work machine of claim 29, wherein the value is automatically updated in response to the amount of torque transmitted to the at least one traction device causing the at least one driven traction device to slip.

32. The work machine of claim 29, wherein the value is automatically updated in response to a location of the work machine.

33. The work machine of claim 29, wherein:

the at least one driven traction device is a first driven traction device,

the drive system further includes a second driven traction device;

the transmission is configured to drive the second traction device; and

the controller is configured to limit an amount of torque transmitted from the transmission to the first and second driven traction devices to the sum of a design limit of the second driven traction device and a ground tractive capacity associated with the first driven traction device.