Wire rope

Abstract

A wire rope having improved durability and that can be used in a medical device to be inserted into a patient's body. The wire rope includes a core wire and side wires. The core wire is a special metal element wire that has a hardness at an outer periphery in a cross-section thereof that is higher than that at a center in the cross-section thereof. The wire rope does not include grease.

What is claimed is: 
     
         1 . A wire rope comprising multiple metal element wires wound together,
 wherein the multiple metal element wires include at least one special metal element wire that has a first hardness at an outer periphery in a cross-section thereof that is higher than a second hardness at a center in the cross-section thereof.   
     
     
         2 . The wire rope according to  claim 1 , wherein the at least one special metal element wire is arranged at a center of the wire rope. 
     
     
         3 . The wire rope according to  claim 2 , wherein the multiple metal element wires consist of the at least one special metal element wire and multiple side metal element wires in contact with the at least one special metal element wire. 
     
     
         4 . The wire rope according to  claim 3 , wherein the at least one special metal element wire has a circular cross-section, and the multiple side metal element wires each have an approximately trapezoidal cross-section. 
     
     
         5 . A bundled wire rope formed by twisting together a plurality of the wire rope according to  claim 4 . 
     
     
         6 . The wire rope according to  claim 1 , wherein:
 the at least one special metal element wire comprises multiple special metal element wires, and   a twisted wire in which the multiple special metal element wires are twisted together is arranged at a center of the wire rope.   
     
     
         7 . The wire rope according to  claim 1 , wherein the wire rope contains no grease.