Track system for traction of an off-road vehicle such as a snowmobile or an all-terrain vehicle (atv)

Abstract

A track system for traction of an off-road vehicle such as a snowmobile or an all-terrain vehicle (ATV). The track system comprises a track-engaging assembly and a track disposed around the track-engaging assembly. The track system may be configured to have a reduced noise profile so as to generate less noise, enhanced track rigidity characteristics to improve its traction and floatation, and/or other features improving use and performance of the off-road vehicle.

1 .- 22 . (canceled) 
     
     
         23 . A track for traction of a vehicle, the track being mountable around a track-engaging assembly that comprises a drive wheel for driving the track and an idler wheel for contacting the track, the track comprising elastomeric material to be flexible around the track-engaging assembly, the track comprising:
 an inner surface for facing the track-engaging assembly, the inner surface comprising an idler wheel path for the idler wheel;   a ground-engaging outer surface for engaging the ground;   a plurality of traction projections projecting from the ground-engaging outer surface; and   a plurality of stiffening rods extending transversally to a longitudinal direction of the track, each stiffening rod having a dimension in a thickness direction of the track that is less where the stiffening rod overlaps the idler wheel path in a widthwise direction of the track than where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track.   
     
     
         24 . The track of  claim 23 , wherein the idler wheel is a roller wheel and the idler wheel path is a rolling path for the roller wheel to roll on a bottom run of the track. 
     
     
         25 . The track of  claim 23 , wherein the idler wheel is a first idler wheel, the idler wheel path is a first idler wheel path, the track-engaging assembly comprises a second idler wheel spaced from the first idler wheel in a widthwise direction of the track-engaging assembly, the inner surface comprises a second idler wheel path for the second idler wheel, the second idler wheel path is spaced from the first idler wheel in the widthwise direction of the track, and the dimension of the stiffening rod in the thickness direction of the track is less where the stiffening rod overlaps the second idler wheel path in the widthwise direction of the track than where the stiffening rod does not overlap the second idler wheel path in the widthwise direction of the track. 
     
     
         26 . The track of  claim 23 , wherein a ratio of (i) a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track over (ii) the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.1. 
     
     
         27 . The track of  claim 23 , wherein a ratio of (i) a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track over (ii) the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.15. 
     
     
         28 . The track of  claim 23 , wherein a ratio of (i) a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track over (ii) the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.2. 
     
     
         29 . The track of  claim 23 , wherein a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track is at least 0.03 inches. 
     
     
         30 . The track of  claim 23 , wherein a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track is at least 0.045 inches. 
     
     
         31 . The track of  claim 23 , wherein a difference between the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track and the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track is at least 0.06 inches. 
     
     
         32 . The track of  claim 23 , wherein the stiffening rod comprises a surface facing the inner surface and receding towards the ground-engaging outer surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track. 
     
     
         33 . The track of  claim 25 , wherein the stiffening rod comprises a surface facing the inner surface and receding towards the ground-engaging outer surface where the stiffening rod overlaps the first idler wheel path in the widthwise direction of the track and where the stiffening rod overlaps the second idler wheel path in the widthwise direction of the track. 
     
     
         34 . The track of  claim 23 , wherein the stiffening rod comprises a recess overlapping the idler wheel path in the widthwise direction of the track. 
     
     
         35 . The track of  claim 34 , wherein a depth of the recess is at least 0.03 inches. 
     
     
         36 . The track of  claim 34 , wherein a depth of the recess is at least 0.045 inches. 
     
     
         37 . The track of  claim 34 , wherein a depth of the recess is at least 0.06 inches. 
     
     
         38 . The track of  claim 34 , wherein a ratio of a depth of the recess over the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.1. 
     
     
         39 . The track of  claim 34 , wherein a ratio of a depth of the recess over the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.15. 
     
     
         40 . The track of  claim 34 , wherein a ratio of a depth of the recess over the dimension of the stiffening rod in the thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.2. 
     
     
         41 . The track of  claim 23 , wherein a longitudinal end portion of the stiffening rod overlaps the idler wheel path in the widthwise direction of the track. 
     
     
         42 . The track of  claim 25 , wherein a first longitudinal end portion of the stiffening rod overlaps the first idler wheel path in the widthwise direction of the track and a second longitudinal end portion of the stiffening rod overlaps the second idler wheel path in the widthwise direction of the track. 
     
     
         43 . The track of  claim 23 , comprising a plurality of reinforcing cables extending generally in the longitudinal direction of the track. 
     
     
         44 . The track of  claim 43 , wherein the reinforcing cables are located between the stiffening rods and the inner surface in the thickness direction of the track. 
     
     
         45 . The track of  claim 43 , wherein the reinforcing cables are located between the stiffening rods and the ground-engaging outer surface in the thickness direction of the track. 
     
     
         46 . The track of  claim 23 , comprising a plurality of drive/guide projections projecting from the inner surface. 
     
     
         47 . The track of  claim 46 , wherein the drive/guide projections are configured for engaging the drive wheel to drive the track. 
     
     
         48 . The track of  claim 23 , wherein a thickness of the track from the inner surface to the ground-engaging outer surface is no more than 0.25 inches. 
     
     
         49 . The track of  claim 23 , wherein the vehicle is a snowmobile and the track is a snowmobile track. 
     
     
         50 . A track for traction of a vehicle, the track being mountable around a track-engaging assembly that comprises a drive wheel for driving the track and an idler wheel for contacting the track, the track comprising elastomeric material to be flexible around the track-engaging assembly, the track comprising:
 an inner surface for facing the track-engaging assembly;   a ground-engaging outer surface for engaging the ground;   a plurality of traction projections projecting from the ground-engaging outer surface; and   a plurality of stiffening rods extending transversally to a longitudinal direction of the track, each stiffening rod being shaped such that a thickness of the elastomeric material between the inner surface and a surface of the stiffening rod facing the inner surface varies in a widthwise direction of the track.   
     
     
         51 . The track of  claim 50 , wherein: the inner surface comprises an idler wheel path for the idler wheel; and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface is greater where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track than where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track. 
     
     
         52 . The track of  claim 51 , wherein the idler wheel is a roller wheel and the idler wheel path is a rolling path for the roller wheel to roll on a bottom run of the track. 
     
     
         53 . The track of  claim 51 , wherein the idler wheel is a first idler wheel, the idler wheel path is a first idler wheel path, the track-engaging assembly comprises a second idler wheel spaced from the first idler wheel in a widthwise direction of the track-engaging assembly, the inner surface comprises a second idler wheel path for the second idler wheel, the second idler wheel path is spaced from the first idler wheel in the widthwise direction of the track, and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface is greater where the stiffening rod overlaps the second idler wheel path in the widthwise direction of the track than where the stiffening rod does not overlap the second idler wheel path in the widthwise direction of the track. 
     
     
         54 . The track of  claim 51 , wherein a ratio of (i) a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track over (ii) a dimension of the stiffening rod in a thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.1. 
     
     
         55 . The track of  claim 51 , wherein a ratio of (i) a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track over (ii) a dimension of the stiffening rod in a thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.15. 
     
     
         56 . The track of  claim 51 , wherein a ratio of (i) a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track over (ii) a dimension of the stiffening rod in a thickness direction of the track where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.2. 
     
     
         57 . The track of  claim 51 , wherein a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.03 inches. 
     
     
         58 . The track of  claim 51 , wherein a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.045 inches. 
     
     
         59 . The track of  claim 51 , wherein a difference between the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod overlaps the idler wheel path in the widthwise direction of the track and the thickness of the elastomeric material between the inner surface and the surface of the stiffening rod facing the inner surface where the stiffening rod does not overlap the idler wheel path in the widthwise direction of the track is at least 0.06 inches. 
     
     
         60 . The track of  claim 50 , wherein the surface of the stiffening rod facing the inner surface comprises a recess. 
     
     
         61 . The track of  claim 60 , wherein a depth of the recess is at least 0.03 inches. 
     
     
         62 . The track of  claim 60 , wherein a depth of the recess is at least 0.045 inches. 
     
     
         63 . The track of  claim 60 , wherein a depth of the recess is at least 0.06 inches. 
     
     
         64 . The track of  claim 60 , wherein a ratio of a depth of the recess over a thickness of the stiffening rod in the thickness direction of the track is at least 0.1. 
     
     
         65 . The track of  claim 60 , wherein a ratio of a depth of the recess over a thickness of the stiffening rod in the thickness direction of the track is at least 0.15. 
     
     
         66 . The track of  claim 60 , wherein a ratio of a depth of the recess over a thickness of the stiffening rod in the thickness direction of the track is at least 0.2. 
     
     
         67 . The track of  claim 51 , wherein a longitudinal end portion of the stiffening rod overlaps the idler wheel path in the widthwise direction of the track. 
     
     
         68 . The track of  claim 53 , wherein a first longitudinal end portion of the stiffening rod overlaps the first idler wheel path in the widthwise direction of the track and a second longitudinal end portion of the stiffening rod overlaps the second idler wheel path in the widthwise direction of the track. 
     
     
         69 . The track of  claim 50 , comprising a plurality of reinforcing cables extending generally in the longitudinal direction of the track. 
     
     
         70 . The track of  claim 69 , wherein the reinforcing cables are located between the stiffening rods and the inner surface in a thickness direction of the track. 
     
     
         71 . The track of  claim 69 , wherein the reinforcing cables are located between the stiffening rods and the ground-engaging outer surface in a thickness direction of the track. 
     
     
         72 . The track of  claim 50 , comprising a plurality of drive/guide projections projecting from the inner surface. 
     
     
         73 . The track of  claim 72 , wherein the drive/guide projections are configured for engaging the drive wheel to drive the track. 
     
     
         74 . The track of  claim 50 , wherein a thickness of the track from the inner surface to the ground-engaging outer surface is no more than 0.25 inches. 
     
     
         75 . The track of  claim 50 , wherein the vehicle is a snowmobile and the track is a snowmobile track. 
     
     
         76 . A track for traction of a vehicle, the track being mountable around a track-engaging assembly that comprises a drive wheel for driving the track and an idler wheel for contacting the track, the track comprising elastomeric material to be flexible around the track-engaging assembly, the track comprising:
 an inner surface for facing the track-engaging assembly, the inner surface comprising an idler wheel path for the idler wheel;   a ground-engaging outer surface for engaging the ground; and   a plurality of traction projections projecting from the ground-engaging outer surface;   
       wherein a shock absorbency of the track is greater where the idler wheel path is located in a widthwise direction of the track than where the idler wheel path is not located in the widthwise direction of the track.