SNOWMOBILE REAR SUSPENSION

Abstract

A snowmobile rear suspension is shown comprised of a linear force element (LFE) positioned outside the envelope of the snowmobile endless track. The LFE is attached at one end to the frame and at the other end to a bell crank. The bell crank is operatively connected to the slide rails. When the slide rails collapse in normal operation, the bell crank strokes the LFE, and the suspension is progressive throughout the range.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments of the present snowmobile will now be discussed with reference to the drawings, where:

FIG. 1 shows a diagrammatical view of a conventional snowmobile suspension system in full rebound;

FIG. 2 shows a diagrammatical view of a conventional snowmobile suspension system in full jounce;

FIG. 3 shows the diagrammatical view of a conventional snowmobile suspension system according to FIG. 1 and 2, with a front load applied;

FIG. 4 shows the diagrammatical view of a conventional snowmobile suspension system according to FIG. 1 and 2, with a rear load applied

FIG. 5 shows a diagrammatical view of a conventional snowmobile front suspension system;

FIG. 6 shows a comparison curve of the prior art versus the improved suspend with a rear load;

FIG. 7 shows a comparison curve of the prior art versus the improved suspend with a front load;

FIG. 8 shows a diagrammatical perspective view of the suspension of the present invention;

FIG. 9 shows a diagrammatical plan view of the suspension of FIG. 8;

FIG. 10 shows a diagrammatical plan view of the suspension of the present invention at full rebound;

FIG. 11 shows a diagrammatical plan view of the suspension of the present invention at full jounce;

FIG. 12 shows a diagrammatical perspective view of an alternate suspension;

FIG. 13 shows a diagrammatical plan view of the suspension of the present invention retro-fit on an existing suspension;

FIG. 14 shows a diagrammatical plan view of another suspension of the present invention retro-fit on an existing suspension;

FIG. 15 shows a perspective view of the suspension of the present invention applied to a tunnel and to slide rails;

FIG. 16 shows a perspective view of the suspension of FIG. 16, with the chassis and tunnel removed;

FIG. 17 shows a plan view of the FIG. 16 embodiment;

FIG. 18 shows an enlarged perspective view of FIG. 16, showing the front suspension mounts;

FIG. 19 shows an enlarged view of the connection of the front suspension mounts of FIG. 18 to the slide rails;

FIG. 20 shows a partial sectional view of one driveshaft assembly;

FIG. 21 shows the driveshaft assembly of FIG. 20, partially disassembled;

FIG. 22 shows a partial sectional view of another possible driveshaft assembly;

FIG. 23 shows the driveshaft assembly of FIG. 22, partially disassembled;

FIG. 24 shows an enlarged perspective view of FIG. 16, showing the rear suspension mounts to the slide rails;

FIG. 25 shows an enlarged perspective view showing the pivotal sliding coupling connection of the rear suspension mounts to the slide rails;

FIG. 26 shows an enlarged perspective view of the rear deflector shield;

FIG. 27 shows an enlarged perspective view of the rear chassis of FIG. 15 removed;

FIG. 28 is a diagrammatical view shows the force vectors applied to the suspension system;

FIG. 29 is a perspective view of an alternate rear chassis removed;

FIG. 30 shows the rear chassis of FIG. 29 attached to a tunnel;

FIG. 31 shows the rear chassis of FIG. 30 with a seat mounting frame;

FIG. 32 shows a seat bun mounted on the seat frame of FIG. 31;

FIG. 33 shows an alternate tunnel mounted seat frame;

FIG. 34 shows a seat bun mounted on the seat frame of FIG. 33;

FIG. 35 is a diagrammatical illustration of the four-link geometry of the embodiment of FIGS. 15-17;

FIG. 36 shows the diagrammatical view of FIG. 35 with front loaded coupling;

FIG. 37 shows the diagrammatical view of FIG. 35 with rear loaded coupling;

FIG. 38 shows a comparison load vs. deflection curve of the prior art versus the improved suspension with a front load;

FIG. 39 shows a comparison load vs. deflection curve of the prior art versus the improved suspension with a rear load;

FIG. 40 shows a comparison curve of regressive versus progressive suspensions;

FIG. 41 shows progressive rates for three load cases;

FIGS. 42-44 are computer simulations of movement of the progressive rear suspension of the present invention;

FIGS. 45-48 are plots characterizing the general behavior of the suspension of the present invention, compared to the behavior of the Polaris IQ 440 suspension;

FIG. 49 compares the current front ride rate to a target front ride rate.

FIG. 50 compares the current center ride rate to a target center ride rate

FIG. 51 compares the current rear ride rate to a target rear ride rate.

FIGS. 52-60 show additional rear suspension embodiments of the present invention.

Claims

1. A snowmobile suspension system, comprising: a frame;slide rails for mounting endless track;at least one linkage between the slide rails and frame, the linkage comprising a pivot link, where the pivot link pivots in response to movement between the slide rails and the frame; andat least one linear force element (LFE) positioned between the pivot link and the frame, whereby pivotal movement of the pivot link strokes the LFE.

2. The snowmobile suspension system of claim 1, wherein the at least one LFE is positioned above the frame.

3. The snowmobile suspension system of claim 2, wherein the at least LFE is substantially horizontal throughout its movement.

4. The snowmobile suspension system of claim 1, wherein the at least one linkage is positioned adjacent to a rear of the slide rails and defines a rear suspension system.

5. The snowmobile suspension system of claim 4, wherein the pivot link is comprised of a bell crank, which connects to one end of the LFE.

6. The snowmobile suspension system of claim 5, wherein the linkage is further comprised of a rear suspension frame operatively linked to the slide rails and the bell crank.

7. The snowmobile suspension system of claim 6, wherein the rear suspension frame is comprised of straddle links, which flank the endless track.

8. The snowmobile suspension system of claim 7, wherein the straddle links are defined as A-shaped links, having plural attachments to the slide rails and a single upper pivot link.

9. The snowmobile suspension system of claim 5, wherein the bell crank is pyramidally shaped, with front corners attached to the frame, rear corners operatively connected to the slide rails, and the apex attached to the LFE.

10. A snowmobile suspension system, comprising: a frame;slide rails for mounting endless track;at least one linkage between the slide rails and frame; andat least one linear force element (LFE) positioned above the frame and operatively connected to the frame and to the at least one linkage.

11. The snowmobile suspension system of claim 10, wherein the at least one linkage is positioned adjacent to a rear of the slide rails and defines a rear suspension system.

12. The snowmobile suspension system of claim 11, wherein the linkage is comprised of a bell crank, which connects to one end of the LFE.

13. The snowmobile suspension system of claim 12, wherein the wherein the linkage is further comprised of a rear suspension frame operatively linked to the slide rails and the bell crank.

14. The snowmobile suspension system of claim 13, wherein the rear suspension frame is comprised of straddle links, which flank the endless track.

15. The snowmobile suspension system of claim 14, wherein the straddle links are defined as A-shaped links, having plural attachments to the slide rails and a single upper pivot link.

16. The snowmobile suspension system of claim 15, wherein the bell crank is pyramidally shaped, with front corners attached to the frame, rear corners operatively connected to the slide rails, and the apex attached to the LFE.

17. A snowmobile suspension system, comprising: a frame;slide rails for mounting endless track;at least one linkage between the slide rails and frame; andat least one linear force element (LFE) positioned substantially horizontally, with one end attached to the frame and one end connected to the at least one linkage.

18. The snowmobile suspension system of claim 17, wherein the at least LFE is positioned above the frame.

19. The snowmobile suspension system of claim 17, wherein the at least one LFE is substantially horizontal throughout its movement.

20. The snowmobile suspension system of claim 17, wherein the linkage is comprised of a pivot link which pivots in response to movement between the slide rails and the frame, and LFE is positioned between the pivot link and the frame, whereby pivotal movement of the pivot link strokes the LFE.

21. The snowmobile suspension system of claim 17, wherein the at least one linkage is positioned adjacent to a rear of the slide rails and defines a rear suspension system.

22. The snowmobile suspension system of claim 21, wherein the pivot link is comprised of a bell crank, which connects to one end of the LFE.

23. The snowmobile suspension system of claim 22, wherein the linkage is comprised of a rear suspension frame operatively linked to the slide rails and the bell crank.

24. The snowmobile suspension system of claim 23, wherein the rear suspension frame is comprised of straddle links, which flank the endless track.

25. The snowmobile suspension system of claim 24, wherein the straddle links are defined as A-shaped links, having plural attachments to the slide rails and a single upper pivot link.

26. The snowmobile suspension system of claim 23, wherein the bell crank is pyramidally shaped, with front corners attached to the frame, rear corners operatively connected to the slide rails, and the apex attached to the LFE.

27. A snowmobile suspension system, comprising: a frame;slide rails coupled to the frame;endless track mounted to the slide rail;at least one linear force element (LFE) positioned outside of the envelope defined by the endless track;a suspension assembly coupling the slide rails to the frame;whereby one end of the LFE is attached to the frame and the opposite end is attached to the suspension assembly, with the endless track passing through the suspension assembly.

28. The snowmobile suspension system of claim 27, wherein the at least one LFE is positioned above the frame.

29. The snowmobile suspension system of claim 27, wherein the at least one LFE is substantially horizontal throughout its movement.

30. The snowmobile suspension system of claim 27, wherein the suspension assembly is comprised of a pivot link which pivots in response to movement between the slide rails and the frame, and LFE is positioned between the pivot link and the frame, whereby pivotal movement of the pivot link strokes the LFE.

31. The snowmobile suspension system of claim 30, wherein the pivot link is comprised of a bell crank, which connects to one end of the LFE.

32. The snowmobile suspension system of claim 27, wherein the suspension assembly is comprised of straddle links, which flank the endless track.

33. The snowmobile suspension system of claim 32, wherein the straddle links are defined as A-shaped links, having plural attachments to the slide rails and a single upper pivot link.

34. The snowmobile suspension system of claim 31, wherein the bell crank is pyramidally shaped, with front corners attached to the frame, rear corners operatively connected to the slide rails, and the apex attached to the LFE.

35. A snowmobile suspension system, comprising: a frame;slide rails for mounting endless track;a suspension system mounted intermediate the frame and the slide rails, the suspension stiffness increasing at least substantially throughout the entire range of suspension travel.

36. The snowmobile suspension system of claim 35, wherein the suspension system is comprised of at least one linear force element (LFE) positioned outside of the envelope defined by the endless track and a suspension assembly coupling the slide rails to the frame; whereby one end of the LFE is attached to the frame and the opposite end is attached to the suspension assembly, with the endless track passing through the suspension assembly.

37. The snowmobile suspension system of claim 36, wherein the at least one LFE is positioned above the frame.

38. The snowmobile suspension system of claim 36, wherein the suspension assembly is comprised of a pivot link which pivots in response to movement between the slide rails and the frame, and the LFE is positioned between the pivot link and the frame, whereby pivotal movement of the pivot link strokes the LFE.

39. The snowmobile suspension system of claim 38, wherein the pivot link is comprised of a bell crank, which connects to one end of the LFE.

40. The snowmobile suspension system of claim 39, wherein the suspension assembly is comprised of straddle links, which flank the endless track.

41. The snowmobile suspension system of claim 35, wherein the suspension system is comprised of forward links operatively coupled adjacent to a front of the slide rails having an effective length (A); rearward links operatively coupled adjacent to a rear of the slide rails having an effective length (B); and at least one linear force element (LFE) positioned intermediate the rearward links and the frame.

42. The snowmobile suspension system of claim 41, wherein the ratio of the links (A/B) is between 1.6 to 2.0.