Heat exchanger and manufacturing method for the same

Abstract

In a heat exchanger, a core portion includes a plurality of plate fins each shaped like a flat plate and a plurality of tubes in which a fluid flows and each of which is inserted into each of the plate fins to be mechanically bonded thereto. Further, an end portion in a longitudinal direction of each of the tubes is bonded to a header plate which constructs a part of a header tank. In this heat exchanger, the tube is bonded to the header plate in a solid phase. Therefore, the plate fins are mechanically bonded to the tube and the end portion of the tube in the longitudinal direction of the tube can be bonded to the header plate without a furnace of a high temperature.

1 . A heat exchanger comprising: 
 a core portion including a plurality of plate fins each shaped like a flat plate and a tube in which a fluid flows, the tube being inserted into the plate fins to be mechanically connected to the plate fins; and    a header plate to which an end portion of the tube in a longitudinal direction of the tube is bonded, and which construct a part of a header tank,    wherein the tube and the header plate are bonded to each other by a solid bonding.    
   
   
       2 . The heat exchanger as in  claim 1 , 
 wherein the tube has an insertion portion inserted into a tube hole provided in the header plate,    wherein the insertion portion of the tube has a flange portion expanded and bent to a surface of the header plate along the entire periphery on a tip side of the insertion portion, and    wherein the tube and the header plate are bonded to each other at an abutting portion where the flange portion abuts on the header plate.    
   
   
       3 . The heat exchanger as in  claim 2 , wherein the flange portion is expanded and bent approximately 90 degrees along the surface of the header plate.  
   
   
       4 . The heat exchanger as in  claim 2 , 
 wherein the header plate has a hole wall portion for defining the tube hole, and the hole wall portion has a tapered portion on a side of the flange portion, and    wherein the tube is formed along the tapered portion and is bonded to the tapered portion to contact the tapered portion.    
   
   
       5 . The heat exchanger as in  claim 2 , wherein the flange portion has a stress relieving portion for relieving a tensile stress that is generated in a peripheral direction when the flange portion is formed at a predetermined position of an outer peripheral portion of the flange portion.  
   
   
       6 . The heat exchanger as in  claim 5 , wherein the stress relieving portion is a portion in which the outer peripheral portion of the flange portion is cut out in a circumferential shape.  
   
   
       7 . The heat exchanger as in  claim 1 , wherein the header plate has a protruding portion for reducing a contact area with the tube, in a bonding portion where the tube is bonded to the header plate.  
   
   
       8 . The heat exchanger as in  claim 2 , 
 wherein the header plate has a hole wall portion for defining the tube hole, and    wherein the hole wall portion has a first chamfered portion formed on a side in which the tube is inserted.    
   
   
       9 . The heat exchanger as in  claim 8 , wherein the hole wall portion has a second chamfered portion formed on a side of the flange portion.  
   
   
       10 . The heat exchanger as in  claim 1 , wherein the tube has a thickness that is in a range from 0.1 mm to 0.5 mm.  
   
   
       11 . The heat exchanger as in  claim 1 , wherein the tube is a flat tube having a flat cross section.  
   
   
       12 . A method for manufacturing a heat exchanger, comprising the steps of: 
 inserting a tube in which a fluid flows into a plurality of plate fins each shaped like a flat plate;    expanding the tube to mechanically connect the tube to the plate fins to form a core portion; and    connecting an end portion of the tube in a longitudinal direction of the tube to a header plate forming a part of a header tank;    vibrating the tube by supersonic vibration in a direction in which a surface of an abutting portion where the tube abuts on the header plate extends; and    solid-bonding the tube to the header plate in a solid phase while applying a predetermined load in a direction in which the tube abuts on the header plate.    
   
   
       13 . The method for manufacturing a heat exchanger as in  claim 12 , further comprising a step of penetrating the tube into a tube hole provided in the header plate upon forming the abutting portion and then bending the end portion in the longitudinal direction of the tube along its entire periphery in such a way as to expand to a surface of the header plate to form a flange portion to make the flange portion abut on the header plate, in the forming of the abutting portion.  
   
   
       14 . The method for manufacturing a heat exchanger as in  claim 13 , further comprising a step of previously forming a stress relieving portion for relieving a tensile stress generated in a circumferential direction at a predetermined portion along the entire periphery of the end portion of the tube in the longitudinal direction of the tube when the end portion of the tube in the longitudinal direction of the tube is bent to the surface of the header plate before forming the flange portion.  
   
   
       15 . The method for manufacturing a heat exchanger as in  claim 12 , further comprising a step of previously forming a protruding portion for reducing a contact area with the tube on the header plate in the abutting portion.  
   
   
       16 . The method for manufacturing a heat exchanger as in  claim 12 , further comprising a step of heating a portion near the abutting portion by heating means when the tube is bonded to the header plate in the solid phase.