Gear backlash elimination and adjustable gear backlash mechanism

• US 20040154422A1
• Filed: 02/10/2003
• Published: 08/12/2004
• Est. Priority Date: 02/10/2003
• Status: Active Grant

• Current Assignee: GM Global Technology Operations Incorporated (Motors Liquidation Co. GUC Trust), Steering Solutions IP Holding Corporation (Nexteer Automotive Group Ltd.)
• Original Assignee: Delphi Technologies, Inc. (BorgWarner Incorporated)
• Inventors: Menjak, Damir, Menjak, Ratko
• Granted Patent: US 6,997,076 B2
• Time in Patent Office: Days
• US Class Current: 74/440
• CPC Class Codes: B62D 1/105 Non-rotatable hubs, e.g. the central part of the steering wheel not rotating
• CPC Class Codes: B62D 5/008 Changing the transfer ratio between the steering wheel and the steering gear by variable supply of energy, e.g. by using a superposition gear
• CPC Class Codes: F16D 1/104 having retaining means rotating with the coupling and acting only by friction
• CPC Class Codes: F16H 55/18 Special devices for taking up backlash for gears having orbital motion F16H1/2863
• CPC Class Codes: F16H 57/0006 Vibration-damping or noise reducing means specially adapted for gearings devices for varying tension of belts, ropes or chains with damping means F16H7/0829; toothed members with construction providing vibration damping F16H55/14; reducing vibrations or noise of the gearbox casing F16H57/028; suppression of vibrations or noise of gear selectors F16H59/0208; control of hydrostatic fluid gearing preventing or reducing vibrations or noise F16H61/4183
• CPC Class Codes: Y10T 74/19623 Backlash take-up
• CPC Class Codes: Y10T 74/19898 Backlash take-up

Abstract

The gear mechanism for minimizing backlash may include a convoluted spring positioned between an external spline of a gear or shaft and an internal spline of a gear. The gear mechanism may include a cam and cam follower arrangement upon two adjacent gears positioned on the same shaft. Two stacked gears may include a U-shaped backlash eliminating element passing through both gears. The gear mechanism may include rollers which may be conically shaped.

Claims

1. A gear mechanism for minimizing backlash, the gear mechanism comprising:

an external gear having an internal spline;

an internal gear positioned within the external gear, the internal gear having an external spline; and

,

a convoluted spring positioned between the internal spline of the external gear and the external spline of the internal gear.

2. The gear mechanism of claim 1 wherein the internal spline of the external gear comprises alternating teeth and grooves, the external spline of the internal gear comprises alternating teeth and grooves, and wherein the teeth of the internal gear are sized to fit within the grooves of the external gear and the teeth of the external gear are sized to fit within the grooves of the internal gear.

3. The gear mechanism of claim 1 wherein the spring comprises alternating rounded protrusions and rounded grooves, wherein the rounded protrusions are seated within grooves in the internal spline of the external gear and the rounded grooves are seated within grooves in the external spline of the internal gear.

4. The gear mechanism of claim 3 wherein one of the rounded grooves includes a break.

5. The gear mechanism of claim 1 wherein the internal gear is formed on a shaft of a steering mechanism.

6. The gear mechanism of claim 1 wherein the internal gear is a planetary gear.

7. A gear mechanism for minimizing backlash, the gear mechanism comprising:

a first shaft having a longitudinal axis;

a first gear positioned on the shaft;

a second gear positioned on the shaft;

a cam positioned on a face of the first gear; and

,

a cam follower positioned on a face of the second gear;

wherein the cam engages with the cam follower.

8. The gear mechanism of claim 7 further comprising a spring adjacent the first gear, the spring allowing movement of the first gear along the longitudinal axis of the shaft.

9. The gear mechanism of claim 8 wherein a spring force F_S of the spring is greater than or equal to F_A, wherein F_A is a force in a direction of the longitudinal axis from a point A where the cam and cam follower abut, and wherein the spring force F_S points in an opposite direction of F_A.

10. The gear mechanism of claim 9 wherein F_A=F sin α

(cos α

−

μ

sin α

), wherein F is transmission load force from the point A, and wherein α

is tangential angle between F and the point A.

11. The gear mechanism of claim 7 further comprising a second shaft having a longitudinal axis parallel to the longitudinal axis of the first shaft, a third gear positioned on the second shaft, wherein rotation of the third gear rotates the second gear, and further wherein backlash between the third gear and the second gear is minimized by the cam and cam follower on the first gear and the second gear.

12. The gear mechanism of claim 11 further comprising a fourth gear positioned on the first shaft, wherein rotation of the first shaft by the second gear rotates the fourth gear, further comprising a third shaft and a fifth gear positioned on the third shaft, wherein rotation of the fourth gear rotates the fifth gear, wherein backlash between the fourth gear and the fifth gear is minimized by a sixth gear positioned adjacent the fourth gear on the first shaft, the sixth gear and the fourth gear including a cam and cam follower arrangement.

13. The gear mechanism of claim 7 wherein the cam is a rounded protrusion on the face of the first gear and the cam follower is a rounded groove on the face of the second gear.

14. The gear mechanism of claim 7 wherein the cam has an annular segment peripheral shape.

15. A gear mechanism for minimizing backlash, the gear mechanism comprising:

a shaft;

a first gear positioned on the shaft;

a second gear positioned on the shaft and adjacent the first gear; and

,

a U-shaped backlash eliminating element passing through both the first gear and the second gear.

16. The gear mechanism of claim 15 wherein the element is elastic and includes a slot between legs of the U-shaped element.

17. The gear mechanism of claim 15 wherein the element is a spring-wire and includes a wide space between legs of the U-shaped element within the first gear and a leg extension extending from one leg of the U-shaped element into the second gear.

18. A gear transmission for minimizing backlash, the gear transmission comprising:

a first shaft;

a first roller positioned on the first shaft;

a first gear positioned on the first shaft;

a second shaft;

a second roller positioned on the second shaft and adjacent the first roller; and

,

a second gear positioned on the second shaft and adjacent the first gear;

wherein the first roller and the second roller abut when teeth of the first gear mesh with teeth of the second gear.

19. The gear transmission of claim 18 wherein the first roller includes an outer layer of an elastic material.

20. The gear transmission of claim 18 further comprising a tolerance ring installed between the second shaft and the second roller.

21. The gear transmission of claim 18 wherein the first roller and the second roller are truncated conically shaped rollers, wherein an outer conical face of the first roller rolls along an outer conical face of the second roller.

22. The gear transmission of claim 21 further comprising a spring positioned between the first gear and the first roller.

23. The gear transmission of claim 21 further comprising an adjustable spring on the first shaft, the adjustable spring adjusting an amount of force applied by the first roller onto the second roller.

24. The gear transmission of claim 23 further comprising a nut for adjusting and securing the spring in a selected position.

25. The gear transmission of claim 21 further comprising an adjustable spring on the second shaft adjacent the second roller, the adjustable spring adjusting an amount of force applied by the second roller onto the first roller, and further comprising a nut for adjusting and securing the spring in a selected position.

26. The gear transmission of claim 25 wherein the second roller includes a recess for receiving the spring.

27. The gear transmission of claim 18 further comprising a third shaft, a third roller positioned on the third shaft, a third gear positioned on the third shaft, a fourth roller positioned on the first shaft, and a fourth gear positioned on the fourth shaft, wherein roller faces of the third roller and the fourth roller abut when teeth of the third gear and the fourth gear mesh.

28. The gear transmission of claim 27 wherein the first roller, second roller, third roller, and fourth roller are truncated conically shaped.

29. The gear transmission of claim 18 wherein the first shaft has a cup shaped end, the first gear and the first roller positioned on the first shaft within the cup shaped end, the second gear positioned within the first gear and the second roller positioned within the first roller.

30. The gear transmission of claim 29 wherein the first roller and the second roller include truncated conically shaped roller faces which abut when teeth of the first gear and second gear mesh.

31. The gear transmission of claim 30 further comprising a spring positioned between the second roller and the second gear.