Heat exchanger, method of manufacturing heat exchanger and plate-shaped fin for heat exchanger

Abstract

A heat exchanger comprises: a plurality of plate-shaped fins, which are laminated on each other at predetermined intervals, on which a plurality of insertion holes having burring portions are formed; and a plurality of tubes inserted into the insertion holes, wherein the burring portions and the tubes are brazed to each other, and at least the burring portions of the plate-shaped fins are composed of a plurality of metallic layers for displacing the burring portions to the side of the insertion holes according to a rise in temperature at the time of brazing.

1 . A heat exchanger comprising: 
 a plurality of plate-shaped fins, which are laminated at predetermined intervals, on which a plurality of insertion holes having burring portions are formed; and    a plurality of tubes inserted into the insertion holes, wherein    the burring portions and the tubes are brazed to each other, and    at least the burring portions of the plate-shaped fins are composed of a plurality of metallic layers for displacing the burring portions to the side of the insertion holes according to a rise in the temperature at the time of brazing.    
   
   
       2 . A heat exchanger according to  claim 1 , wherein the metallic layer is composed of a core material and a brazing material clad onto one of the faces of the core material.  
   
   
       3 . A heat exchanger according to  claim 2 , wherein a sacrificial material, which conducts a sacrificial corrosion action upon the tube is provided on a face of the metallic layer opposite to the face on which the brazing material is provided.  
   
   
       4 . A heat exchanger according to  claim 1 , the metallic layer including: a core material; a first brazing material; and a second clad material, wherein and the first brazing material and the second clad material are respectively clad on a surface and a reverse face of the core material.  
   
   
       5 . A heat exchanger according to  claim 1 , wherein the direction in which rising points of the burring portions are connected to each other is the same as a rolling direction of the plate-shapes fins.  
   
   
       6 . A heat exchanger according to  claim 1 , wherein 
 a cross section of the tube is formed into a flat shape,    the burring portions are formed on two sides of the insertion hole corresponding to a long side of the flat cross section of the tube, and    a positioning portion for positioning the tube is provided in a portion of the insertion hole corresponding to an end portion of the flat cross section in the longitudinal direction.    
   
   
       7 . A heat exchanger according to  claim 1 , wherein 
 two cutout portions, which are cut out onto the side opposite to the insertion hole side, are formed at a peripheral edge of the insertion hole, and    the burring portion is formed at a base point of a connecting line to connect bottom portions of the cutout portions between the two cutout portions.    
   
   
       8 . A heat exchanger according to  claim 1 , wherein a rib, which is extended along a side portion of the plate-shaped fin, is provided in the side portion of the plate-shaped fin in a direction in which a plurality of tubes are arranged.  
   
   
       9 . A heat exchanger according to  claim 1 , wherein 
 the burring portions are arranged at the peripheral edge of the insertion hole being opposed to each other, and    a portion, the rising height of which is higher than the opposing side, is formed in each burring portion.    
   
   
       10 . A heat exchanger according to  claim 7 , wherein a thickness removing portion is formed in the neighborhood of a portion where the rising points of the burring portions are connected to each other or in the neighborhood of the base point.  
   
   
       11 . A heat exchanger according to  claim 1 , the burring portion including: 
 a first metallic layer arranged on the insertion hole side; and    a second metallic layer, which is arranged on the side opposite to the insertion hole side, to be penetrated into the first metallic layer and to swell the first metallic layer so that the burring portion can be displaced to the insertion hole side.    
   
   
       12 . A heat exchanger according to  claim 1 , the burring portion including a plurality of metallic layers, the coefficients of thermal expansion of which are different from each other so as to exhibit the bimetal effect so that the burring portion can be displaced to the insertion hole side.  
   
   
       13 . A method of manufacturing a heat exchanger comprising the steps of: 
 laminating a plurality of plate-shaped fins, in which a plurality of insertion holes having the burring portions are formed, at regular intervals;    inserting a plurality of tubes into the insertion holes; and    brazing the burring portions and the tubes to each other, wherein    at least the burring portions of the plate-shaped fins are composed of a plurality of metallic material layers so that the burring portions can be displaced to the insertion holes side according to a rise in the temperature to the brazing temperature, and    after the tubes have been inserted into the insertion holes, the burring portions are displaced and contacted with the tubes and brazing is conducted.    
   
   
       14 . A method of manufacturing a heat exchanger according to  claim 13 , wherein gaps are formed between the burring portions and the tubes when the tubes are inserted into the insertion holes.  
   
   
       15 . A method of manufacturing a heat exchanger according to  claim 14 , wherein the tubes are inserted into the insertion holes at the normal temperature.  
   
   
       16 . A method of manufacturing a heat exchanger according to  claim 13 , the burring portion including: 
 a first metallic layer arranged on the insertion hole side; and    a second metallic layer, which is arranged on the side opposite to the insertion hole side, to be penetrated into the first metallic layer and to swell the first metallic layer so that the burring portion can be displaced to the insertion hole side.    
   
   
       17 . A method of manufacturing a heat exchanger according to  claim 13 , the burring portion including: a plurality of metallic layers, the coefficients of thermal expansion of which are different from each other so as to exhibit the bimetal effect so that the burring portion can be displaced to the insertion hole side.  
   
   
       18 . A plate-shaped fin used for a heat exchanger in which the burring portions are provided in the insertion holes into which a plurality of tubes are inserted, wherein 
 at least the burring portions are composed of a plurality of metallic material layers, and the burring portions are displaced to the insertion hole side according to a rise in the temperature to the temperature at the time of brazing.    
   
   
       19 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein the metallic layer is composed of a core material and a brazing material clad on one of the faces of the core material.  
   
   
       20 . A plate-shaped fin used for a heat exchanger according to  claim 19 , wherein a sacrificial corrosion layer, which conducts a sacrificial corrosion action upon the tube, is provided on a face opposite to the face on which the brazing material is provided.  
   
   
       21 . A plate-shaped fin used for a heat exchanger according to  claim 18 , the metallic layer including: a core material; a first brazing material; and a second clad material, wherein and the first brazing material and the second clad material are respectively clad on a surface and a reverse face of the core material.  
   
   
       22 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein a direction in which rising points of the burring portions are connected to each other is the same as its rolling direction.  
   
   
       23 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein 
 a cross section of the tube is formed into a flat shape,    the burring portions are formed on two sides of the insertion hole corresponding to a long side of the flat cross section of the tube, and    a positioning portion for positioning the tube is provided in a portion of the insertion hole corresponding to an end portion of the flat cross section in the longitudinal direction.    
   
   
       24 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein 
 two cutout portions, which are cut out onto the side opposite to the insertion hole side, are formed at a peripheral edge of the insertion hole, and    the burring portion is formed at a base point of a connecting line to connect bottom portions of the cutout portions between the two cutout portions.    
   
   
       25 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein a rib, which is extended along a side portion of the plate-shaped fin, is provided in the side portion of the plate-shaped fin in a direction in which the tubes are arranged.  
   
   
       26 . A plate-shaped fin used for a heat exchanger according to  claim 18 , wherein 
 the burring portions are arranged at the peripheral edge of the insertion hole being opposed to each other, and    a portion, the rising height of which is higher than the opposing side, is formed in each burring portion.    
   
   
       27 . A plate-shaped fin used for a heat exchanger according to  claim 20 , wherein 
 a thickness removing portion is formed in the neighborhood of a portion where the rising points of the burring portions are connected to each other or in the neighborhood of the base point.    
   
   
       28 . A plate-shaped fin used for a heat exchanger according to  claim 18 , the burring portion including: 
 a first metallic layer arranged on the insertion hole side; and    a second metallic layer, which is arranged on the side opposite to the insertion hole side, to be penetrated into the first metallic layer and to swell the first metallic layer so that the burring portion can be displaced to the insertion hole side.    
   
   
       29 . A plate-shaped fin used for a heat exchanger according to  claim 18 , the burring portion including: a plurality of metallic layers, the coefficients of thermal expansion of which are different from each other so as to exhibit the bimetal effect so that the burring portion can be displaced to the insertion hole side.