Tire with pre-stressed toroidal element

Abstract

A non-pneumatic tire has a crown region and a pair of sidewall regions, including a first sidewall region and a second sidewall region. The non-pneumatic tire includes a pair of beads, including a first bead and a second bead, and a toroidal element. The toroidal element includes an inner region, an outer region, and a central region. At least a portion of the central region is more elastic than the inner and outer regions. The toroidal element includes a crown portion extending across the crown region of the non-pneumatic tire, a first sidewall portion extending along at least a portion of the first sidewall region of the non-pneumatic tire, and a second sidewall portion extending along at least a portion of the second sidewall region of the non-pneumatic tire. The toroidal element is pre-stressed such that when the non-pneumatic tire is mounted to a rim, the first sidewall portion of the toroidal element exerts a first axially outward force of at least 1000 pounds against the rim, and such that the second sidewall portion of the toroidal element exerts a second axially outward force of at least 1000 pounds against the rim.

What is claimed is: 
     
         1 . A non-pneumatic tire having a crown region and a pair of sidewall regions, including a first sidewall region and a second sidewall region, the non-pneumatic tire comprising:
 a pair of beads, including a first bead and a second bead;   a toroidal element,
 wherein the toroidal element includes an inner region, an outer region, and a central region, 
 wherein at least a portion of the central region is more elastic than the inner and outer regions, 
 wherein the toroidal element includes a crown portion extending across the crown region of the non-pneumatic tire, 
 wherein the toroidal element includes a first sidewall portion extending along at least a portion of the first sidewall region of the non-pneumatic tire, 
 wherein the toroidal element includes a second sidewall portion extending along at least a portion of the second sidewall region of the non-pneumatic tire, and wherein the toroidal element is pre-stressed such that when the non-pneumatic tire is mounted to a rim, the first sidewall portion of the toroidal element exerts a first axially outward force of at least 1000 pounds against the rim, and such that the second sidewall portion of the toroidal element exerts a second axially outward force of at least 1000 pounds against the rim. 
   
     
     
         2 . The non-pneumatic tire of  claim 1 , wherein the central region of the toroidal element includes at least one high stiffness layer between a pair of lower stiffness layers. 
     
     
         3 . The non-pneumatic tire of  claim 1 , wherein the inner region, the outer region, and the central region extend from the first bead to the second bead. 
     
     
         4 . The non-pneumatic tire of  claim 1 , wherein the first sidewall portion of the toroidal element exerts an axially outward force of at least 5000 pounds, and such that the second sidewall portion of the toroidal element exerts an axially outward force of at least 5000 pounds. 
     
     
         5 . The non-pneumatic tire of  claim 1 , further comprising at least one body ply defining a plurality of body ply layers, wherein the body ply layers form the inner region and the outer region of the toroidal element. 
     
     
         6 . The non-pneumatic tire of  claim 5 , wherein the central region of the toroidal element includes a first inner rubber component and a second inner rubber component separated by a second body ply. 
     
     
         7 . The non-pneumatic tire of  claim 5 , wherein the central region of the toroidal element includes a third rubber component separated from the second rubber component by a third body ply. 
     
     
         8 . A tire and rim assembly comprising:
 a rim having a pair of wheel flanges, including a first wheel flange and a second wheel flange;   a tire fastened to the rim, the tire including:
 a crown region; 
 a first sidewall region extending from the crown region to a first bead area, the first sidewall region of the tire being affixed to the first wheel flange of the rim; 
 a second sidewall region opposite the first sidewall region, the second sidewall region extending from the crown region to a second bead area, the second sidewall region of the tire being affixed to the second wheel flange of the rim; 
 a toroidal element extending across a crown region of the tire, further extending along at least a portion of the first sidewall region of the tire, and further extending along at least a portion of the second sidewall region of the tire, the toroidal element having a central region located between inner and outer regions,
 wherein the central region is more elastic than the inner and outer regions, 
 wherein the toroidal element is pre-stressed such that the toroidal element exerts a first axially outward force of at least 1000 pounds against the first wheel flange of the rim, and 
 wherein the toroidal element exerts a second axially outward force of at least 1000 pounds against the second wheel flange of the rim. 
 
   
     
     
         9 . The tire and rim assembly of  claim 8 , wherein the central region of the toroidal element includes a layer of rubber. 
     
     
         10 . The tire and rim assembly of  claim 9 , wherein the layer of rubber includes a first layer of rubber and a second layer of rubber, separated by a body ply. 
     
     
         11 . The tire and rim assembly of  claim 9 , wherein the layer of rubber includes a first layer of rubber, a second layer of rubber, and a third layer of rubber, wherein the first layer of rubber and the second layer of rubber are separated by a first body ply, and wherein the second layer of rubber and the third layer of rubber are separated by a second body ply. 
     
     
         12 . The tire and rim assembly of  claim 8 , wherein the first sidewall region of the tire is bolted to the first wheel flange of the rim and wherein the second sidewall region of the tire is bolted to the second wheel flange of the rim. 
     
     
         13 . The tire and rim assembly of  claim 8 , wherein the first axially outward force is at least 5000 pounds, and wherein the second axially outward force is at least 5000 pounds. 
     
     
         14 . The tire and rim assembly of  claim 8 , wherein the toroidal element extends from a first bead area to a second bead area. 
     
     
         15 . A method of making a tire and rim assembly, the method comprising:
 providing a rim having a pair of rim flanges;   forming a green tire having:
 a green tread, 
 a pair of bead regions, including a first bead region and a second bead region, each of the pair of bead regions being axially outside and radially below the tread, 
 green sidewall regions extending from the tread to the bead regions, 
 a green toroidal element disposed radially below the tread and radially below at least a portion of each sidewall region, the green toroidal element having a pair of inextensible ply layers with green rubber disposed between the inextensible ply layers, 
 wherein the pair of inextensible ply layers and the green rubber disposed between the ply layers extend from the first bead to the second bead; 
   curing the green tire;   applying at least 1000 pounds of force to move the pair of bead regions axially inward; and   mounting the tire on the rim by placing the pair of bead regions in the pair of rim flanges.   
     
     
         16 . The method of  claim 15 , further comprising affixing the bead regions of the tire to the flanges of the rim. 
     
     
         17 . The method of  claim 16 , wherein the affixing the bead regions of the tire to the wheel flanges of the rim includes bolting the bead regions of the tire to the flanges of the rim. 
     
     
         18 . The method of  claim 15 , wherein the moving the pair of bead regions axially inward includes applying at least 1000 pounds of force to move the pair of bead regions axially inward. 
     
     
         19 . The method of  claim 15 , wherein the moving the pair of bead regions axially inward includes applying at least 5000 pounds of force to move the pair of bead regions axially inward. 
     
     
         20 . The method of  claim 15 , wherein the tire is a non-pneumatic tire.