CVT system having discrete selectable speed ranges

• US 7,641,588 B2
• Filed: 01/31/2007
• Issued: 01/05/2010
• Est. Priority Date: 01/31/2007
• Status: Active Grant

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Thomson, Norval P., Martinez, Alberto Jr.
• Primary Examiner(s): Wright; Dirk
• Application Number:
  US11/700,196
• Publication Number:
  US 20080183358A1
• Time in Patent Office: 1,070 Days
• Field of Search: 477/42, 477/37, 477/108, 180/170, 180/175, 180/176, 701/95
• US Class Current: 477/108
• CPC Class Codes: B60W 10/06 including control of combustion engines
• CPC Class Codes: B60W 10/101 Infinitely variable gearings
• CPC Class Codes: B60W 2540/10 Accelerator pedal position
• CPC Class Codes: B60Y 2200/415 Wheel loaders
• CPC Class Codes: F16H 59/105 consisting of electrical switches or sensors
• CPC Class Codes: F16H 59/18 dependent on the position of the accelerator pedal
• CPC Class Codes: F16H 59/44 dependent on machine speed of the machine, e.g. the vehicle
• CPC Class Codes: F16H 61/47 for achieving a target output speed

Abstract

A continuously variable transmission control system is disclosed. The control system has a first operator input device to receive operator input and produce a corresponding first signal indicative of a selected one of a plurality of available predetermined discrete machine travel speed ranges. The control system also has a second operator input device to receive operator input and produce a corresponding second signal indicative of desired machine travel. The control system also has a power source operatively coupled to drive a continuously-variable transmission, and a controller configured to regulate at least one of an output of the power source and an output of the continuously variable transmission in response to the first and second signals such that an actual machine travel speed remains within the selected one of the plurality of predetermined discrete machine travel speed ranges.

Claims

1. A transmission control system, comprising:

a first operator input device to receive operator input and produce a corresponding first signal indicative of a selected one of a plurality of available predetermined discrete machine travel speed ranges;

a second operator input device to receive operator input and produce a corresponding second signal indicative of desired machine travel;

a power source operatively coupled to drive a continuously-variable transmission; and

a controller to regulate at least one of an output of the power source and an output of the continuously variable transmission in response to the first and second signals such that an actual machine travel speed remains within the selected one of the plurality of available predetermined discrete machine travel speed ranges.

2. The control system of claim 1, wherein the controller is further configured to toggle between a first state and a second state in response to operator input, the first state allowing machine travel within a selected one of the plurality of available predetermined discrete machine travel speed ranges, and the second state allowing machine travel at any speed within the plurality of available predetermined discrete machine travel speed ranges.

3. The control system of claim 1, wherein the second operator input device is movable through a displacement range from a minimum position to a maximum position, and the second signal is proportional to a displacement position of the second operator input device.

4. The control system of claim 3, wherein the second operator input device is a foot pedal.

5. The transmission control system of claim 1, wherein the output of the power source includes a speed.

6. The transmission control system of claim 5, wherein the controller regulates an output speed of the power source by adjusting at least one of a fuel flow and an air flow.

7. The transmission control system of claim 1, wherein the output of the power source includes a torque.

8. The transmission control system of claim 1, wherein the output of the continuously variable transmission includes a speed.

9. The transmission control system of claim 8, wherein the controller regulates the speed of the continuously variable transmission by adjusting a torque-to-speed ratio.

10. The transmission control system of claim 1, wherein the controller is further configured to display the selected one of a plurality of predetermined discrete machine travel speed ranges.

11. A method of controlling machine travel speed, comprising:

transmitting a power output through a continuously variable transmission to propel a machine;

receiving a first signal indicative of a selected one of a plurality of available predetermined discrete machine travel speed ranges;

receiving a second signal indicative of desired machine travel; and

regulating at least one of the power output and an output of the continuously variable transmission in response to the first and second signals such that an actual machine travel speed remains within the selected one of the plurality of available predetermined discrete machine travel speed ranges.

12. The method of claim 11, wherein regulating includes controlling a speed of the power output.

13. The method of claim 11, wherein regulating includes controlling a torque of the power output.

14. The method of claim 11, wherein regulating includes controlling a torque-to-speed output ratio of the continuously variable transmission.

15. The method of claim 11, further including displaying the selected range for operator confirmation.

16. A machine, comprising:

a power source operatively coupled to drive a continuously-variable transmission;

a traction device operatively coupled to the transmission to propel the machine;

an operator station including an operator interface for receiving operator input; and

a controller configured to;

receive a first signal from the operator interface indicative of a selected one of a plurality of available predetermined discrete machine travel speed ranges;

receive a second signal from the operator interface indicative of desired machine travel; and

regulate at least one of an output of the power source and an output of the continuously variable transmission in response to the first and second signals such that an actual machine travel speed remains within the selected one of the plurality of predetermined discrete machine travel speed ranges.

17. The machine of claim 16, wherein the operator interface includes an input device movable through a displacement range from a minimum position to a maximum position, and the second signal is proportional to a displacement position of the input device.

18. The machine of claim 16, wherein the output of the continuously variable transmission includes a speed.

19. The machine of claim 18, wherein the controller regulates the speed of the continuously variable transmission by adjusting a torque-to-speed ratio.

20. The machine of claim 16, wherein the controller is further configured to display the selected one of a plurality of predetermined discrete travel speed ranges.