Joint structure of header tank and connector in heat exchanger, and method of joining thereof

Abstract

A joint structure of a header tank and a connector in a heat exchanger includes a header tank ( 1 ) including a plate wall ( 1 c ) formed with a first communication hole ( 1 a ). The joint structure includes a block-shaped connector ( 2 ) having a second communication hole ( 2 b ) positioned to the first communication hole ( 1 a ) and joined to the header tank ( 1 ). The first communication hole ( 1 a ) is smaller than the second communication hole ( 2 b ). The first communication hole ( 1 a ) has therearound a periphery ( 1 b ) caulked and fixed on an inner peripheral surface of the second communication hole ( 2 a ) by burring formation.

1 . A joint structure of a header tank and a connector in a heat exchanger comprising: 
 a header tank including a plate wall formed with a first communication hole; and    a block-shaped connector having a second communication hole positioned to the first communication hole and joined to the header tank,    wherein the first communication hole is smaller than the second communication hole,    wherein the first communication hole has therearound a periphery caulked and fixed on an inner peripheral surface of the second communication hole by burring formation.    
   
   
       2 . The joint structure according to  claim 1 , 
 wherein the header tank and the connector caulked and fixed on each other by burring formation are brazed to each other.    
   
   
       3 . The joint structure according to  claim 1 , 
 wherein the connector comprises a first portion diverged in a concave form,    wherein the joint structure further comprises a header-tank backup member mating with the connector and having a second portion converged in a convex form,    wherein the diverged first portion and the converged second portion hold the plate wall therebetween.    
   
   
       4 . A method of joining a header tank and a connector in a heat exchanger, comprising: 
 forming, on a plate wall of a header tank of a heat exchanger, a first communication hole smaller than a second communication hole of a block-shaped connector;    positioning the first and second communication holes to each other;    inserting a punch into the header tank to burring form a periphery around the first communication hole, with the first and second communication holes positioned to each other;    caulking and fixing the periphery around the first communication hole on an inner peripheral surface of the second communication hole by the punch; and    brazing the header tank and the connector caulked and fixed.    
   
   
       5 . The method according to  claim 4 , further comprising: 
 applying a brazing material on an outer surface of the plate wall of a header tank before the step of caulking and fixing by burring formation; and    brazing the header tank and the connector to each other with the brazing material.