Brazed structure and method of manufacturing the same

Abstract

In a brazed structure, a first member has a first portion defined by one of a recessed portion and a hole, and a second member has a second portion brazed to the first portion with a copper brazing material. The first member has a coefficient of thermal expansion that is smaller than that of the second member.

1 . A brazed structure comprising: 
 a first member having a first portion that is defined by one of a recessed portion and a hole; and    a second member having a second portion brazed to the first portion with a copper brazing material, wherein the first member has a coefficient of thermal expansion smaller than that of the second member.    
   
   
       2 . The brazed structure according to  claim 1 , wherein 
 the first member and the second member are made of different materials,    one of the first member and the second member has a coating, and    the coating is made of a material that is brazed to the other one of the first and second member with diffusion of the copper brazing material.    
   
   
       3 . The brazed structure according to  claim 2 , wherein the material of the coating contains one of copper and nickel.  
   
   
       4 . The brazed structure according to  claim 1 , wherein 
 the first member and the second member are included in members of a heat exchanger that performs heat exchange between an internal fluid flowing therein and an external fluid flowing outside thereof.    
   
   
       5 . The brazed structure according to  claim 4 , wherein 
 the first member is included in a header tank of the heat exchanger in which the internal fluid flows, the header tank forms a hole as the first portion,    the second member is a tube of the heat exchanger in which the internal fluid flows, and the tube has a tube end brazed in the hole of the header tank as the second portion.    
   
   
       6 . The brazed structure according to  claim 5 , wherein the tube encloses an inner fin.  
   
   
       7 . The brazed structure according to  claim 4 , wherein 
 the first member and the second member are made of one of copper and copper alloy, respectively.    
   
   
       8 . The brazed structure according to  claim 4 , wherein 
 the first member is made of one of stainless steel and steel and has a coating containing one of copper and nickel, and    the second member is made of one of copper and copper alloy.    
   
   
       9 . The brazed structure according to  claim 4 , wherein 
 the first member forms a first tube member of a tube of the heat exchanger, the first tube member has a substantially U-shaped cross-section and includes a main portion and side portions extending from sides of the main portion, to define the recessed portion therein,    the second member forms a second tube member of the tube, the second tube member has a substantially U-shaped cross-section and includes a main portion and side portions extending from sides of the main portion, and    the side portions of the second tube member are brazed to the side portions of the first tube member in an inside of the recessed portion.    
   
   
       10 . The brazed structure according to  claim 9 , wherein the first tube member and the second tube member interpose an inner fin therebetween.  
   
   
       11 . A method of manufacturing a brazed structure, the brazed structure having a first member having a first portion defined by one of a recessed portion and a hole and a second member having a second portion brazed in the first portion, the method comprising steps of: 
 arranging the second portion of the second member in the first portion of the first member; and    brazing the second portion of the second member to the first portion of the first member while thermally expanding the second member more than the first member.    
   
   
       12 . The method according to  claim 11 , wherein 
 in the arranging the first member and the second member define an initial clearance between the first portion and the second portion, and    in the brazing the initial clearance is reduced by a difference of coefficient of thermal expansion of the first member and the second member.