Pneumatic tire

Abstract

In the pneumatic tire of this invention, at least the outermost one of a plurality of rubber layers between the carcass and tread has been reinforced with a plurality of steel cords. Each of these steel cords is a single-strand steel cord with an elongation at break of not less than 4% and at least one of its component wires does not form a common circumcircle with the remaining wires. This pneumatic tire features a high anti-cut property, high wire tenacity utilization rate, high rigidity and inhibited onset and growth of separation. The curve circumscribing the cross-sections of the constituent wires of each steel cord is not a true circle. Furthermore, a high resistance to nail penetration is assured by arranging the steel cords in such a manner that, for a large majority of steel cords, the direction of maximum offset span of the circumscribing curve is substantially coincidental with the width direction of the outermost layer of rubber.

What is claimed is:  
     
         1 . A pneumatic tire in which at least one of a plurality of rubber layers between its carcass and tread that constitutes the outermost layer has been reinforced with a plurality of steel cords, characterized in that each of steel cords reinforcing said outermost layer has a single-strand structure with an elongation at break of not less than 4 percent and includes one or more constituent wires that do not constitute a common circumcircle.  
     
     
         2 . A pneumatic tire in which at least one of a plurality of rubber layers between its carcass and tread that constitutes the outermost layer has been reinforced with a plurality of steel cords, characterized in that each of steel cords reinforcing said outermost layer has a single-strand construction with an elongation at break of not less than 4 percent, that the curve circumscribing the cross sections of all the constituent wires of the steel cord is not a true circle, and that with regard to a large majority of said steel cords, the direction of maximum offset span of the circumcircle is substantially coincidental with the width direction of said outermost layer.  
     
     
         3 . The pneumatic tire of  claim 1  or  2  which is further characterized in that some of constituent wires of the steel cord vary in shaping rate from the remaining wires.  
     
     
         4 . The pneumatic wire of  claim 1  or  2  which is further characterized in that the steel cord is one prepared by flattening a steel cord having a truely circular circumscribing curve by means of a roller.  
     
     
         5 . The pneumatic tire of  claim 1  or  2  which is further characterized in that one or more of constituent wires of the steel cord vary in diameter from the remaining wires.