Guidewire

Abstract

A guidewire has a distal-most end portion that retains its desired shape. The guidewire includes a first brazing member joining a distal end of a core shaft to a distal end of an outer coil, and a second brazing member provided adjacent to and on a proximal side of the first brazing member. The melting point of the first brazing member is higher than the melting point of the second brazing member. As a result, deformation of the first brazing member due to a heat produced during formation of the second brazing member is prevented or minimized.

What is claimed is: 
     
         1 . A guidewire comprising:
 a core shaft,   an outer coil surrounding an outer periphery of the core shaft,   a first brazing member that joins a distal end of the core shaft to a distal end of the outer coil, and   a second brazing member provided adjacent to and on a proximal side of the first brazing member, wherein   a melting point of the first brazing member is higher than a melting point of the second brazing member.   
     
     
         2 . The guidewire according to  claim 1 , further comprising:
 an inner coil provided between the outer coil and the core shaft, wherein   the second brazing member is provided between the outer coil and the inner coil but is not provided between the inner coil and the core shaft.   
     
     
         3 . The guidewire according to  claim 1 , wherein the distal end of the core shaft and the distal end of the outer coil penetrate into the first brazing member. 
     
     
         4 . The guidewire according to  claim 1 , wherein the second brazing member abuts the proximal side of the first brazing member. 
     
     
         5 . The guidewire according to  claim 3 , wherein the second brazing member abuts the proximal side of the first brazing member. 
     
     
         6 . The guidewire according to  claim 1 , wherein the first brazing member is formed of a brazing material containing gold, silver and tin. 
     
     
         7 . The guidewire according to  claim 6 , wherein the second brazing member is formed of a gold-tin brazing material. 
     
     
         8 . The guidewire according to  claim 6 , wherein the second brazing member is formed of a silver-tin brazing material. 
     
     
         9 . The guidewire according to  claim 2 , wherein the first brazing member is formed of a brazing material containing gold, silver and tin. 
     
     
         10 . The guidewire according to  claim 9 , wherein the second brazing member is formed of a gold-tin brazing material. 
     
     
         11 . The guidewire according to  claim 9 , wherein the second brazing member is formed of a silver-tin brazing material. 
     
     
         12 . The guidewire according to claim I, wherein
 a distal part of the guidewire includes a curved part, and   the second brazing member is provided in the curved part.   
     
     
         13 . The guidewire according to  claim 2 , wherein
 a distal part of the guidewire includes a curved part, and   the second brazing member is provided in the curved part.   
     
     
         14 . The guidewire according to  claim 6 , wherein
 a distal part of the guidewire includes a curved part, and   the second brazing member is provided in the curved part.   
     
     
         15 . The guidewire according to  claim 9 , wherein
 a distal part of the guidewire includes a curved part, and   the second brazing member is provided in the curved part.