Track system for traction of a vehicle

Abstract

A track for traction of a vehicle, such as an agricultural vehicle, an industrial vehicle (e.g., a construction vehicle), a military vehicle, or another off-road vehicle, is provided. The track comprises a ground-engaging outer surface for engaging the ground and a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track. The traction projections may be designed to enhance their resistance to deterioration during use. For example, a blowout resistance of each traction projection may be enhanced to prevent or at least reduce a potential for blowout of the traction projection under repeated loads which may induce heat buildup within it. Also, a wear resistance of the traction projection may be enhanced such that the traction projection wears less rapidly. A system for protecting a track against potential occurrence of blowout is also provided.

1 .- 31 . (canceled) 
     
     
         32 . A track for traction of a vehicle, the track being mountable around a plurality of wheels that comprises a drive wheel for driving the track, the track being elastomeric to flex around the wheels, the track comprising:
 an inner surface for facing the wheels;   a ground-engaging outer surface for engaging the ground; and   a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track, each traction projection of the plurality of traction projections comprising:
 an outer elastomeric material extending to a periphery of the traction projection; and 
 an inner elastomeric material disposed inwardly of the outer elastomeric material and more resistant to blowout than the outer elastomeric material to prevent blowout of the traction projection during use of the track. 
   
     
     
         33 . The track of  claim 32 , wherein a blowout time of the inner elastomeric material is greater than a blowout time of the outer elastomeric material under ASTM D-623. 
     
     
         34 . The track of  claim 33 , wherein a ratio of the blowout time of the inner elastomeric material over the blowout time of the outer elastomeric material is at least 2. 
     
     
         35 . The track of  claim 33 , wherein a ratio of the blowout time of the inner elastomeric material over the blowout time of the outer elastomeric material is at least 5. 
     
     
         36 . The track of  claim 33 , wherein a ratio of the blowout time of the inner elastomeric material over the blowout time of the outer elastomeric material is at least 10. 
     
     
         37 . The track of  claim 32 , wherein the inner elastomeric material has a blowout time of at least plural minutes under ASTM D-623. 
     
     
         38 . The track of  claim 37 , wherein the inner elastomeric material has a blowout time of at least fifteen minutes under ASTM D-623. 
     
     
         39 . The track of  claim 32 , wherein a blowout temperature of the inner elastomeric material is greater than a blowout temperature of the outer elastomeric material under ASTM D-623. 
     
     
         40 . The track of  claim 39 , wherein a ratio of the blowout temperature of the inner elastomeric material over the blowout temperature of the outer elastomeric material is at least 1.3. 
     
     
         41 . The track of  claim 39 , wherein a ratio of the blowout temperature of the inner elastomeric material over the blowout temperature of the outer elastomeric material is at least 1.5. 
     
     
         42 . The track of  claim 32 , wherein the outer elastomeric material is more resistant to wear than the inner elastomeric material. 
     
     
         43 . The track of  claim 42 , wherein an abrasion resistance of the outer elastomeric material is greater than an abrasion resistance of the inner elastomeric material under ASTM D-5963. 
     
     
         44 . The track of  claim 43 , wherein each of the abrasion resistance of the outer elastomeric material and the abrasion resistance of the inner elastomeric material is expressed as a volumetric loss and a ratio of the abrasion resistance of the inner elastomeric material over the abrasion resistance of the outer elastomeric material is no more than 0.7. 
     
     
         45 . The track of  claim 43 , wherein each of the abrasion resistance of the outer elastomeric material and the abrasion resistance of the inner elastomeric material is expressed as a volumetric loss and a ratio of the abrasion resistance of the inner elastomeric material over the abrasion resistance of the outer elastomeric material is no more than 0.5. 
     
     
         46 . The track of  claim 32 , wherein a volumetric loss at the periphery of the traction projection under ASTM D-5963 is no more than 110 mm 3 . 
     
     
         47 . The track of  claim 32 , wherein a volumetric loss at the periphery of the traction projection under ASTM D-5963 is no more than 100 mm 3 . 
     
     
         48 . The track of  claim 32 , wherein a volumetric loss at the periphery of the traction projection under ASTM D-5963 is no more than 90 mm 3 . 
     
     
         49 . The track of  claim 32 , wherein a ratio of a volume of the inner elastomeric material over a volume of the traction projection is at least 0.2. 
     
     
         50 . The track of  claim 32 , wherein a ratio of a volume of the inner elastomeric material over a volume of the traction projection is at least 0.3. 
     
     
         51 . The track of  claim 32 , wherein the inner elastomeric material occupies a majority of a volume of the traction projection. 
     
     
         52 . The track of  claim 51 , wherein a ratio of a volume of the inner elastomeric material over the volume of the traction projection is at least 0.8. 
     
     
         53 . The track of  claim 32 , wherein a ratio of a dimension of the inner elastomeric material in a thicknesswise direction of the track over a dimension of the traction projection in the thicknesswise direction of the track is at least 0.2. 
     
     
         54 . The track of  claim 32 , wherein a ratio of a dimension of the inner elastomeric material in a thicknesswise direction of the track over a dimension of the traction projection in the thicknesswise direction of the track is at least 0.3. 
     
     
         55 . The track of  claim 32 , wherein a dimension of the inner elastomeric material in a thicknesswise direction of the track corresponds to a majority of a dimension of the traction projection in the thicknesswise direction of the track. 
     
     
         56 . The track of  claim 55 , wherein a ratio of a dimension of the inner elastomeric material in the thicknesswise direction of the track over a dimension of the traction projection in the thicknesswise direction of the track is at least 0.8. 
     
     
         57 . The track of  claim 32 , wherein a dimension of the inner elastomeric material in a thicknesswise direction of the track is greater than a dimension of the outer elastomeric material in the thicknesswise direction of the track. 
     
     
         58 . The track of  claim 32 , wherein the inner elastomeric material extends to the periphery of the traction projection and forms a smaller part of the periphery of the traction projection than the outer elastomeric material. 
     
     
         59 . The track of  claim 32 , wherein: the inner elastomeric material is a first inner elastomeric material; and the traction projection comprises a second inner elastomeric material disposed between and different from the outer elastomeric material and the first inner elastomeric material. 
     
     
         60 . A track for traction of a vehicle, the track being mountable around a plurality of wheels that comprises a drive wheel for driving the track, the track being elastomeric to flex around the wheels, the track comprising:
 an inner surface for facing the wheels;   a ground-engaging outer surface for engaging the ground; and   a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track, each traction projection of the plurality of traction projections comprising:
 an outer elastomeric material extending to a periphery of the traction projection; and 
 an inner elastomeric material disposed inwardly of the outer elastomeric material and having a blowout time of at least plural minutes under ASTM D-623. 
   
     
     
         61 . A track for traction of a vehicle, the track being mountable around a plurality of wheels that comprises a drive wheel for driving the track, the track being elastomeric to flex around the wheels, the track comprising:
 an inner surface for facing the wheels;   a ground-engaging outer surface for engaging the ground; and   a plurality of traction projections projecting from the ground-engaging outer surface and distributed in a longitudinal direction of the track, each traction projection of the plurality of traction projections comprising:
 an outer elastomeric material extending to a periphery of the traction projection; and 
 an inner elastomeric material disposed inwardly of the outer elastomeric material and configured to generate less heat buildup than the outer elastomeric material.