Method of manufacturing heat exchanger and heat exchanger

Abstract

A heat exchanger has a core including tubes and a core plate coupled to the core. The core plate has a coupling wall on which tube insertion holes are formed for receiving ends of the tubes. The coupling wall has an end portion and a clearance portion both coupled to the tubes. The clearance portion is integrally connected to the end portion and spaced from an imaginary plane, on which the end portion is located. A paste brazing material is applied to a joining portion between the core plate and each tube by a brazing material applying device through a space provided between the clearance portion and the imaginary plane.

1 . A method of manufacturing a heat exchanger, comprising:
 forming a core plate having a coupling wall for coupling to tubes, wherein the coupling wall includes an end portion and a clearance portion, the clearance portion is spaced from an imaginary plane on which the end portion is located, and tube insertion holes are formed across the end portion and the clearance portion;   preliminarily fixing the core plate and the tubes by inserting ends of the tubes into the tube insertion holes of the core plate;   applying a paste brazing material to joining portions between the core plate and the tubes by a brazing material applying device; and   heating the preliminarily fixed core plate and tubes for brazing the joining portions.   
   
   
       2 . The method according to  claim 1 , wherein
 the forming includes forming an inclined surface on a perimeter of each tube insertion hole, the inclined surface inclined relative to a direction perpendicular to the imaginary plane, and   in the applying, the paste brazing material is applied between the inclined surface and an outer wall of the tube.   
   
   
       3 . The method according to  claim 1 , wherein the tubes have a substantially flat tubular shape. 
   
   
       4 . The method according to  claim 1 , wherein each of the core plate and the tubes has an outer surface made of one of copper, copper alloy, and nickel. 
   
   
       5 . The method according to  claim 1 , wherein the paste brazing material has a melting point between 550 and 700° C. 
   
   
       6 . The method according to  claim 1 , wherein
 in the applying, the paste brazing material is applied to a part of each joining portion, and   in the heating, the core plate is arranged such that the part to which the paste brazing material is applied is located higher than a remaining part of the respective joining portion.   
   
   
       7 . The method according to  claim 1 , wherein the core plate has a coefficient of linear expansion smaller than that of the tubes. 
   
   
       8 . The method according to  claim 1 , wherein
 in the applying, the paste brazing material is applied to a part of the joining portion by entering an end of the brazing material applying device in a space defined between the clearance portion and the imaginary plane.   
   
   
       9 . The method according to  claim 1 , wherein
 in the applying, the paste brazing material is applied to a part of the joining portion, the part being formed on the clearance portion, and   in the heating, the core plate is arranged such that the clearance portion is located higher than the end portion.   
   
   
       10 . The method according to  claim 1 , wherein the brazing material applying device has a straight end portion. 
   
   
       11 . The method according to  claim 1 , wherein
 the preliminarily fixing includes arranging fins between the tubes.   
   
   
       12 . A heat exchanger comprising:
 a core having tubes and fins; and   a header tank having a core plate, the core plate having a coupling wall formed with tube insertion holes, wherein ends of the tubes are received in and brazed with the tube insertion holes, wherein the coupling wall includes an end portion and a clearance portion, the end portion is located on an imaginary plane, and the clearance portion is spaced from the imaginary plane.   
   
   
       13 . The heat exchanger according to  claim 12 , wherein
 the tube insertion holes extend across the clearance portion and the end portion, and   the clearance portion is at least partly located within the core.   
   
   
       14 . The heat exchanger according to  claim 12 , wherein
 the imaginary plane is perpendicular to a longitudinal direction of the tubes, and   the clearance portion is inclined relative to the imaginary plane.   
   
   
       15 . The heat exchanger according to  claim 12 , wherein the clearance portion has a curved wall.