Method of manufacturing a composite rim

Abstract

A method of manufacturing a composite rim includes following steps of: disposing a composite material on an outer surface of an air bag to form a semi-formed rim, wherein the air bag is a completely closed annular tube without any through opening on the outer surface and contains a thermal expansion material thereinside; disposing the semi-formed rim in a mold; and heating the thermal expansion material so that the thermal expansion material expands and inflates the air bag and the semi-formed rim is then solidified.

What is claimed is: 
     
         1 . A method of manufacturing a composite rim, including steps of:
 disposing a composite material on an outer surface of an air bag to form a semi-formed rim, wherein the air bag is a completely closed annular tube without any through opening on the outer surface and contains a thermal expansion material thereinside;   disposing the semi-formed rim in a mold; and   heating the thermal expansion material so that the thermal expansion material expands and inflates the air bag and the semi-formed rim is then solidified.   
     
     
         2 . The method of  claim 1 , wherein the composite material is a carbon fiber composite material. 
     
     
         3 . The method of  claim 1 , wherein the pressure generated by the thermal expansion material to inflate the air bag is 1 kg/cm 2  to 20 kg/cm 2.    
     
     
         4 . The method of  claim 3 , wherein the thermal expansion material produces gas during inflation of the air bag. 
     
     
         5 . The method of  claim 4 , wherein the thermal expansion material is ammonium carbonate. 
     
     
         6 . The method of  claim 5 , wherein the composite material is a carbon fiber composite material; after the inflation of the thermal expansion material, the air bag contains a part of the thermal expansion material which is solid state and the gas which is produced from the thermal expansion material; after the semi-formed rim is solidified, the air bag and the thermal expansion material are removed. 
     
     
         7 . The method of  claim 1 , wherein the air bag is inflated by the thermal expansion material of a volume change of 15%. 
     
     
         8 . The method of  claim 7 , wherein the thermal expansion material is wax. 
     
     
         9 . The method of  claim 8 , wherein the composite material is carbon fiber composite material; after the semi-formed rim is solidified, the air bag and the thermal expansion material are removed. 
     
     
         10 . The method of  claim 1 , wherein the thermal expansion material is gas.