Heat exchanger unit and method of manufacturing the same

Abstract

A heat exchanger unit has tubes each having a body section and at least one of an inner pipe section and an outer pipe section extending from the body section and defining an opening at an end. Each of the inner pipe section and the outer pipe section has a first portion and a second portion adjacent to the first portion. The tubes are stacked such that the body sections are spaced from each other. Further, the inner pipe section is received in the outer pipe section such that the first portion of the inner pipe section overlaps the first portion of the outer pipe section, and the second portions of the inner and outer pipe sections are located on opposite sides of the overlapped first portions. The first and second portions of the inner pipe section have an outer diameter smaller than an inner diameter of the first and second portions of the outer pipe section.

1 . A heat exchanger unit comprising a plurality of tubes, each tube having a flat body section and at least one of an inner pipe section and an outer pipe section extending from the body section in a direction perpendicular to an axis of the body section and defining an opening at an end, the body section defining a passage through which a heat medium flows, wherein 
 each of the inner pipe section and the outer pipe section includes a first portion and a second portion adjacent to the first portion,    the tubes are stacked such that the body sections are spaced from each other for performing heat exchange between the heat medium and an object existing between the adjacent body sections and the inner pipe section and the outer pipe section are coupled to each other and joined through side walls thereof, thereby to construct a header part that allows communication between adjacent body sections, wherein    the inner pipe section is disposed in the outer pipe section such that the first portion of the inner pipe section overlaps the first portion of the outer pipe section, and the second portions of the inner pipe section and the outer pipe section are located on opposite sides of the overlapped first portions in an axial direction of the inner pipe section and the outer pipe section, and    the first portion and the second portion of the inner pipe section have an outer diameter smaller than an inner diameter of the first portion and the second portion of the outer pipe section.    
   
   
       2 . The heat exchanger unit according to  claim 1 , wherein 
 the inner pipe section and the outer pipe section are brazed to each other,    the outer pipe section has a flange at an end, and an end of the flange has a diameter larger than the inner diameter of the first portion of the outer pipe section.    
   
   
       3 . The heat exchanger unit according to  claim 1 , wherein 
 the inner pipe section further includes a third portion that extends between the body section and the second portion and defines a base portion of the inner pipe section, and    the third portion has an outer diameter larger than the outer diameter of the first portion of the inner pipe section.    
   
   
       4 . A heat exchanger unit comprising a plurality of tubes, each tube having a flat body section and at least one of an inner pipe section and an outer pipe section extending from the body section in a direction perpendicular to an axis of the body section and defining an opening at an end, the body section defining a passage through which a heat medium flows, wherein 
 the tubes are stacked such that the body sections are spaced from each other for performing heat exchange between the heat medium and an object existing between the adjacent body sections, and the inner pipe section and the outer pipe section are coupled such that an outer side wall of the inner pipe section is brazed to an inner side wall of the outer pipe section, thereby to construct a header part that allows communication between adjacent body sections,    the outer pipe section has a flange at an end, and    the flange has a diameter larger than an inner diameter of a remaining portion of the outer pipe section.    
   
   
       5 . The heat exchanger unit according to  claim 1 , wherein the object is an electronic component.  
   
   
       6 . The heat exchanger unit according to  claim 1 , wherein 
 the body section of each tube has a diaphragm portion on a periphery of each of the inner pipe section and the outer pipe section, and    the diaphragm portion is deformed in a direction substantially parallel to an axis of the header part.    
   
   
       7 . The heat exchanger unit according to  claim 6 , wherein 
 each of the inner pipe section and the outer pipe section includes a third portion adjacent to the body section, and    the third portion of the inner pipe section has an inner diameter substantially equal to an inner diameter of the third portion of the outer pipe section.    
   
   
       8 . The heat exchanger unit according to  claim 1 , wherein 
 each of the tubes that are located at other than ends of a stack of tubes has a pair of outer plates, a middle plate and corrugated inner fins,    the middle plate is disposed between the outer plates,    the inner fins are disposed between the outer plates and the middle plate, and    the passages are defined by spaces between the outer plates and the middle plate.    
   
   
       9 . The heat exchanger unit according to  claim 8 , wherein each of the outer plates includes a core made of a metallic material, and an outer surface of the tube is defined by a bare surface of the core.  
   
   
       10 . The heat exchanger unit according to  claim 8 , wherein each of the outer plates is formed of a brazing sheet that has a core and a sacrificial anode material disposed on a surface of the core, and an inner surface of the tube is defined by the sacrificial anode material.  
   
   
       11 . The heat exchanger unit according to  claim 8 , wherein the pair of outer plates is directly brazed at ends thereof.  
   
   
       12 . The heat exchanger unit according to  claim 11 , wherein each of the outer plates has a brazing material on a surface that defines an inner surface of the tube.  
   
   
       13 . The heat exchanger unit according to  claim 11 , wherein 
 each of the outer plates is formed of a brazing sheet having a core, a sacrificial anode material disposed on a surface of the core, and a brazing material disposed on the sacrificial anode material, and    an inner surface of the tube is defined by the brazing material.    
   
   
       14 . The heat exchanger unit according to  claim 8 , wherein the pair of outer plates is formed of a single plate member.  
   
   
       15 . The heat exchanger unit according to  claim 8 , wherein each of the outer plates has a core, and each of the inner fins is made of a material having an electric potential lower than that of the core of the outer plate.  
   
   
       16 . The heat exchanger unit according to  claim 10 , wherein each of the inner fins has a core made of a material having an electric potential higher than that of the sacrificial anode material of the outer plate.  
   
   
       17 . The heat exchanger unit according to  claim 16 , wherein the core of the inner fin has a potential difference with respect to the sacrificial anode material in a range between 0 and +50 mV.  
   
   
       18 . The heat exchanger unit according to  claim 8 , wherein each of the outer plates has a core, and the middle plate is made of a material having an electric potential lower than that of the core of the outer plate.  
   
   
       19 . The heat exchanger unit according to  claim 1 , further comprising: 
 an electronic component arranged between the tubes such that the electronic component is cooled by the heat medium flowing in the tubes.    
   
   
       20 . The heat exchanger unit according to  claim 1 , wherein the outer pipe section has no portion that contacts the end of the inner pipe section in the axial direction of the outer pipe section.  
   
   
       21 . A method of manufacturing a heat exchanger unit, the method comprising: 
 forming tubes, wherein each tube has a body section having a flat tubular shape and at least one of an inner pipe section and an outer pipe section that extend from the body section in a direction perpendicular to an axis of the body section, each of the inner pipe section and the outer pipe section has a first portion and a second portion adjacent to the first portion, the first portion and the second portion of the inner pipe section have an outer diameter smaller than an inner diameter of the first portion and the second portion of the outer pipe section; and    stacking the tubes such that the inner pipe section is inserted in the outer pipe section of the adjacent tube, wherein the first portion of the inner pipe section overlaps the first portion of the outer pipe section, and the second portions of the inner and outer pipe sections are disposed on opposite sides of the overlapped first portions in an axial direction of the inner and outer pipe sections.    
   
   
       22 . The method according to  claim 21 , further comprising: 
 joining an outer side wall of the inner pipe section and an inner side wall of the outer pipe section in a condition that a spacing jig is placed between the adjacent tubes.    
   
   
       23 . The method according to  claim 21 , wherein the inner side wall of the outer pipe section has no portion that contacts an end of the inner pipe section when the inner pipe section is inserted in the outer pipe section.  
   
   
       24 . A method of manufacturing a heat exchanger unit, the method comprising: 
 forming tubes, wherein each tube has a body section having a flat tubular shape and at least one of an inner pipe section and an outer pipe section that extend from the body section in a direction perpendicular to an axis of the body section and define an opening at an end, and the outer pipe section has a flange at an end;    stacking the tubes such that the inner pipe section is inserted in the outer pipe section of the adjacent tube in a condition that a brazing material is placed between the flange of the outer pipe section and the inner pipe section; and    brazing an outer side wall of the inner pipe section and an inner side wall of the outer pipe section.    
   
   
       25 . The method according to  claim 24 , wherein 
 the brazing material is a ring-shaped wire brazing material, and    the flange has an outer diameter larger than an outer diameter of the wire brazing material.    
   
   
       26 . The method according to  claim 24 , wherein the inner pipe section and the outer pipe section are brazed in a condition that a spacing jig is placed between the adjacent tubes.