Factory steering rack centering and preventing pinch points using electric power steering system

• US 8,584,516 B2
• Filed: 10/21/2011
• Issued: 11/19/2013
• Est. Priority Date: 06/09/2010
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Ellis, Nathaniel, Sweigart, Andrew M., Powell, Nathan Adam, Driscoll, Lonnie Eugene
• Primary Examiner(s): Hurley, Kevin
• Application Number:
  US13/278,475
• Publication Number:
  US 20120061171A1
• Time in Patent Office: 760 Days
• Field of Search: 180/443, 180/444, 180/446, 731/170.2
• US Class Current: 73/117.02
• CPC Class Codes: B62D 1/10 Hubs; Connecting hubs to steering columns, e.g. adjustable B62D1/11 takes precedence
• CPC Class Codes: B62D 5/0457 characterised by control features of the drive means as such

Abstract

A method is provided for centering a steering rack in an automotive vehicle, particularly a vehicle that includes an electric power steering (EPS) system. The centering method includes locating a center by using an electric motor of the EPS system. The method includes temporarily locking the steering rack in place and subsequently installing a steering wheel to a steering column. An on-board processor or ECU of the automotive vehicle determines or locates the center of the rack by detecting the first and second ends of the rack when at least one of a velocity of the electric motor reaches zero, a current of the electric motor reaches a preselected level, and steering angle of the electric motor stabilizes. The method monitors potential pinch point zones and reverses turning of the tires upon reaching the pinch threshold level and the automatic centering process is terminated.

Claims

1. A method of detecting potential pinching during centering of a steering rack in an automotive vehicle that includes an electric power steering (EPS) assembly having an electric motor in the vehicle for steering and an angular position sensor to sense motor angle, the method comprising:

locating a center of a steering rack of the EPS by using the electric motor and the angular position sensor of the EPS to detect first and second ends of the steering rack; and

stopping movement during the centering process if a pinch threshold level is exceeded.

2. The method of claim 1 further including reversing movement if the pinch threshold level is exceeded.

3. The method of claim 1 wherein the stopping step is operational only after detecting an end of rack threshold level.

4. The method of claim 1 further comprising installing a steering wheel to a steering column after the locating step.

5. The method of claim 4 further comprising temporarily locking the steering rack in place until the installing step is completed.

6. The method of claim 5 wherein the EPS electric motor and angular position sensor are used for positioning the steering rack at the center and electromechanically holding the rack in the center.

7. The method of claim 4 further comprising operatively communicating with an on-board processor of the automotive vehicle and running a program to determine the center of the rack.

8. The method of claim 7 wherein the program running step includes moving the rack with the electric motor to a first end of the rack and subsequently moving the rack to a second end of the rack.

9. The method of claim 8 further includes detecting the first and second ends of the rack when at least one of a velocity of the electric motor reaches zero, current of the electric motor reaches a preselected level, and angle of the electric motor stabilizes.

10. The method of claim 9 further includes moving the rack with the electric motor to a position that is one-half of a total stroke between the first and second ends.

11. The method of claim 4 further comprising operatively coupling an interface controller with on-board vehicle diagnostics.

12. The method of claim 11 further includes generating a first signal if the center is not located or a second signal if the center is located.

13. A method of centering a steering rack operatively associated with an electric power steering (EPS) assembly having an electric motor of an automotive vehicle that has an electronic control unit (ECU), the method comprising:

moving the rack with the electric motor to a first end of the rack;

moving the rack with the electric motor to a second end of the rack;

communicating data associated with the moving the rack to the ECU;

interrupting the moving step if a preselected pinch level is detected by at least one of electric motor current, electric motor velocity, steering angle and tie rod load; and

positioning the steering rack at the center with the EPS electric motor based on the data communicated to the ECU.

14. The method of claim 13 further including reversing movement of the wheels if the pinch threshold level is exceeded.

15. The method of claim 13 wherein movement of the rack turns vehicle tires toward one of a full left-hand turn and a full right-hand turn.

16. The method of claim 15 wherein potential pinch points between the tires and the automotive vehicle are associated with each tire after the tires have reached the full left-hand turn and the full right-hand turn and the tires are turned toward a straight-ahead position.

17. The method of claim 13 wherein the monitoring for the preselected pinch level occurs after tires have reached a full turn at an end of rack and movement is reversed toward a straight-ahead position.

18. The method of claim 17 wherein the interrupting step includes stopping turning of the tires.

19. The method of claim 17 wherein the interrupting step includes reversing movement of the wheels if the pinch threshold level is exceeded.

20. The method of claim 17 wherein the pinch level is less than an end of rack threshold level.