Heat exchanger manufacturing method and diameter enlargement tool

Abstract

A heat exchanger manufacturing method, including rolling a metal sheet into a roll shape to form a tube-shaped body, inserting the tube-shaped body through a through hole formed at a metal fin, and loosening the metal sheet that has been rolled into a roll shape to enlarge the diameter of the tube-shaped body and place an outer peripheral face of the tube-shaped body in contact with a hole wall of the through hole, and after enlarging the diameter, joining together a roll-overlap portion of the metal sheet that has been rolled into a roll shape.

1 . A heat exchanger manufacturing method, comprising:
 rolling a metal sheet into a roll shape to form a tube-shaped body;   inserting the tube-shaped body through a through hole formed at a metal fin, and loosening the metal sheet that has been rolled into a roll shape to enlarge the diameter of the tube-shaped body and place an outer peripheral face of the tube-shaped body in contact with a hole wall of the through hole; and   after enlarging the diameter, joining together a roll-overlap portion of the metal sheet that has been rolled into a roll shape.   
     
     
         2 . The heat exchanger manufacturing method of  claim 1 , wherein, in the enlarging of the diameter, inserting a diameter enlargement tool, with an external diameter that is larger than an internal diameter of the tube-shaped body prior to diameter enlargement, inside the tube-shaped body to forcibly loosen the metal sheet that has been rolled into a roll shape and enlarge the diameter of the tube-shaped body. 
     
     
         3 . The heat exchanger manufacturing method of  claim 2 , wherein the metal sheet has an undulating portion formed on one sheet face and, in the forming of the tube-shaped body, rolling the metal sheet into a roll shape to form the tube-shaped body with the undulating portion at an inner side thereof. 
     
     
         4 . The heat exchanger manufacturing method of  claim 2 , comprising configuring the metal sheet by aluminum. 
     
     
         5 . The heat exchanger manufacturing method of  claim 2 , wherein the diameter enlargement tool comprises:
 a circular column-shaped main body that is inserted inside the tube-shaped body;   ribs that are provided at intervals in a circumferential direction around an outer peripheral face of the main body, that project outwardly from the main body outer peripheral face, that extend from an end portion of the main body at an insertion direction side toward an opposite side to the insertion direction, and that contact an inner peripheral face of the tube-shaped body; and   inclined portions that are formed at insertion direction leading end portions of the ribs, and that have a projection height from the main body outer peripheral face that gradually increases toward the opposite side to the insertion direction.   
     
     
         6 . The heat exchanger manufacturing method of  claim 5 , wherein the ribs extend in a spiral shape toward the opposite side of the main body to the insertion direction, with the direction of the spiral being set as an opposite direction to a roll-up direction of the metal sheet that has been rolled into a roll shape. 
     
     
         7 . The heat exchanger manufacturing method of  claim 5 , wherein:
 the ribs extend in straight line shapes toward the opposite side of the main body to the insertion direction; and   an interval between respective contact portions, at which two of the ribs disposed on either side of a peripheral inside edge portion of the metal sheet that has been rolled into a roll shape contact the inner peripheral face of the tube-shaped body, widens toward the opposite side to the insertion direction.   
     
     
         8 . A diameter enlargement tool to enlarge the diameter of a tube-shaped body formed by rolling a metal sheet into a roll shape, the diameter enlargement tool comprising:
 a circular column-shaped main body that is inserted inside the tube-shaped body;   ribs that are provided at intervals in a circumferential direction around an outer peripheral face of the main body, that project outward from the main body outer peripheral face, that extend from an end portion of the main body at an insertion direction side toward an opposite side to the insertion direction, and that contact an inner peripheral face of the tube-shaped body; and   inclined portions that are formed at insertion direction leading end portions of the ribs, and that have a projection height from the main body outer peripheral face that gradually increases toward the opposite side to the insertion direction, wherein   an external diameter of the diameter enlargement tool is larger than an internal diameter of the tube-shaped body.