Heat exchanger

Abstract

A heat exchanger includes two header tanks and a plurality of heat exchange tubes. The header tanks each include an outside plate, an inside plate, and an intermediate plate. The outside plate has an outwardly bulging portion(s). The inside plate has a plurality of tube insertion holes. The intermediate plate has communication holes for allowing communication of the tube insertion holes with the outwardly bulging portion of the header tank. A pair of inclined portions inclined in a fanning-out fashion toward the inside plate are formed at inside-plate-side edge portions of opposite wall surfaces of each communication hole which extend in the hole-length direction. Projecting portions of the inside plate are formed by bending, toward the intermediate plate, portions of the inside plate located at opposite edges of each tube insertion hole which extend in the hole-length direction. The projecting portions are closely brazed to the corresponding inclined portions.

1 . A heat exchanger comprising a pair of header tanks disposed apart from each other and a plurality of flat heat exchange tubes disposed in parallel at intervals between the two header tanks and having opposite end portions connected to the respective header tanks, each of the two header tanks being configured such that an outside plate, an inside plate, and an intermediate plate intervening between the outside and inside plates are brazed together in layers, the outside plate having an outwardly bulging portion extending in a longitudinal direction thereof and having an opening closed by the intermediate plate, the inside plate having a plurality of tube insertion holes in the form of through-holes formed in a region corresponding to the outwardly bulging portion of the outside plate and spaced apart from one another along a longitudinal direction thereof, and the intermediate plate having a plurality of communication holes in the form of through-holes formed for allowing the respective tube insertion holes of the inside plate to communicate with the interior of the outwardly bulging portion of the outside plate, 
 wherein a pair of inclined portions inclined in a fanning-out fashion toward the inside plate are formed at inside-plate-side edge portions of opposite wall surfaces of each communication hole of the intermediate plate which extend in a hole-length direction of the communication hole;    a pair of projecting portions projecting toward the intermediate plate are formed on a surface of the inside plate which faces the intermediate plate, the projecting portions being located at positions corresponding to opposite edges of each tube insertion hole which extend in a hole-length direction of the tube insertion hole and being in close contact with the corresponding inclined portions of the intermediate plate; and    the projecting portions are brazed to the corresponding inclined portions.    
   
   
       2 . A heat exchanger according to  claim 1 , wherein opposite end portions of the heat exchange tubes are inserted through the respective tube insertion holes of the inside plates and into the respective communication holes of the intermediate plates of the two header tanks; entire outer peripheral surfaces of opposite end portions of the heat exchange tubes are brazed to the respective entire peripheral wall surfaces of the tube insertion holes of the inside plates; and at least opposite-side surfaces, extending in a tube-width direction, of the entire outer peripheral surfaces of opposite end portions of the heat exchange tubes and at least opposite wall surfaces, extending in the hole-length direction, of the entire peripheral wall surfaces of the communication holes of the intermediate plates are respectively brazed together.  
   
   
       3 . A heat exchanger according to  claim 1 , wherein a hole width of the tube insertion hole of the inside plate and a hole width of the communication hole of the intermediate plate are equal.  
   
   
       4 . A heat exchanger according to  claim 1 , wherein Wp≦(Wt+0.8) and Hp≦(Ht+0.3) are satisfied, where Wp (mm) is a dimension of the communication hole of the intermediate plate as measured in the hole-length direction, Hp (mm) is a dimension of the communication hole of the intermediate plate as measured in a hole-width direction, Wt (mm) is a tube width of the heat exchange tube, and Ht (mm) is a tube height of the heat exchange tube.  
   
   
       5 . A heat exchanger according to  claim 1 , wherein the projecting portions of the inside plate are formed by bending, toward the intermediate plate, portions of the inside plate corresponding to opposite edges of each tube insertion hole which extend along in the hole-length direction of the tube insertion hole.  
   
   
       6 . A heat exchanger according to  claim 1 , wherein stepped portions are formed on a peripheral wall surface of each communication hole of the intermediate plate to be located at opposite end portions of the communication hole with respect to the hole-length direction, the stepped portions projecting inward with respect to the hole-length direction and engaging an end surface of the corresponding heat exchange tube.  
   
   
       7 . A heat exchanger according to  claim 6 , wherein a projecting height of each stepped portion of the intermediate plate from the peripheral wall surface of the corresponding communication hole is determined so as not to cover a refrigerant channel of the corresponding heat exchange tube.  
   
   
       8 . A heat exchanger according to  claim 1 , wherein each heat exchange tube is brazed to a peripheral wall surface of the corresponding communication hole of the intermediate plate by use of a brazing material on an outer peripheral surface of the heat exchange tube.  
   
   
       9 . A heat exchanger according to  claim 8 , wherein the heat exchange tube comprises a pair of flat walls facing each other and two side walls each extending between opposed side edges of the two flat walls and is formed by bending a tube-forming sheet-like member in the form of an aluminum brazing sheet having a brazing material layer on each of opposite sides.