Pneumatic tire and method of producing the same

Abstract

A pneumatic tire comprises a spiral belt formed by spirally winding a cord(s) along a circumferential direction of a torus tread, wherein the spiral belt is comprised of at least one layer constructed with a combination of two different cords each having an initial tension of not less than 50 cN/cord.

What is claimed is:  
     
         1 . In a pneumatic tire comprising a spiral belt formed by spirally winding a cord(s) along a circumferential direction of a torus tread, the improvement wherein the spiral belt is comprised of at least one layer constructed with a combination of two different cords consisting of a steel cord and a fiber reinforcing cord each having an initial tension of not less than 50 cN/cord.  
     
     
         2 . A pneumatic tire according to  claim 1 , wherein the fiber reinforcing cord is made from a resin material or an inorganic material.  
     
     
         3 . A pneumatic tire according to  claim 2 , wherein the resin material is selected from aromatic polyamide, polyethylene naphthalate, polyethylene terephthalate, rayon and aliphatic polyamide, and the inorganic material is selected from glass and carbon.  
     
     
         4 . A pneumatic tire according to  claim 1 , wherein the two different cords are continuously arranged from an end of the tread to the other end thereof in a widthwise direction.  
     
     
         5 . A pneumatic tire according to  claim 1 , wherein one cord among the two different cords is arranged on both side portions of the spiral belt in the widthwise direction.  
     
     
         6 . A pneumatic tire according to  claim 1 , wherein one cord among the two different cords is arranged on a central portion of the spiral belt in the widthwise direction.  
     
     
         7 . A method of producing a pneumatic tire comprising a spiral belt formed by spirally winding a cord(s) along a circumferential direction of a torus tread, which comprises arranging a double-start type head in a cord winding machine, and simultaneously winding one to five steel cords and one to five fiber reinforcing cords from one end of the tread toward the other end thereof in a widthwise direction through the cord winding machine.