Abstract:
Provided is a heat exchanger in which drainage performance of a tube and a fin is improved while preventing reduction in heat exchange efficiency. The heat exchanger includes: a tube having flat surfaces opposed to each other at a predetermined interval; and a fin including a bent portion and a flat portion which are alternately formed in a longitudinal direction, the bent portion being joined to the opposing flat surfaces of the tube. The fin has a predetermined lateral range (bent portion) in the bent portion which is brought into contact with one of the opposing flat surfaces, the predetermined lateral range being bent toward another of the opposing flat surfaces and joined to the another of the opposing flat surfaces, thereby forming a communication path.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to a heat exchanger, and more particularly, to a fin structure in a heat exchanger. 
       BACKGROUND ART 
       [0002]    Conventionally, heat exchangers have been utilized in, for example, an air conditioning apparatus. The air conditioning apparatus includes, for example, an indoor heat exchanger and an outdoor heat exchanger. It is known that, in the indoor heat exchanger in the case of cooling operation and in the outdoor heat exchanger in the case of heating operation, condensed water is easily generated through dew condensation. The condensed water is liable to accumulate between a tube and a fin of the heat exchanger, which may inhibit an air flow to cause not only reduction in heat exchange efficiency, but also frost formation in the outdoor heat exchanger during heating operation, for example. 
         [0003]    To address this problem, as described in, for example, Patent Literature 1, there has been proposed a heat exchanger in which, for drainage of condensed water accumulated in the heat exchanger, a corrugated fin including an inclined portion and a curved portion is joined by brazing between flat heat-transfer tubes (tubes) arranged in a vertical direction, and slits are formed at a plurality of positions in the curved portion of the corrugated fin so as to pass therethrough in the vertical direction. 
         [0004]    With such a heat exchanger, it is conceived that, indeed, the condensed water generated through dew condensation on the surfaces of the flat heat-transfer tube and the corrugated fin is guided downward through the slits formed in the curved portion of the corrugated fin. 
       CITATION LIST 
     Patent Literature 
       [0000]    
       
         [PTL 1] Japanese Patent Application Laid-Open No. 2006-105415 (claim 1, paragraphs [0015] to [0018], FIG. 3) 
       
     
       SUMMARY OF INVENTION 
     Technical Problem 
       [0006]    However, the curved portion of the corrugated fin is a part to be joined to the flat heat-transfer tube, and with this contact of this part, heat moves between the flat heat-transfer tube and the corrugated fin. Therefore, when a slit is formed in the curved portion of the corrugated fin as in the heat exchanger described in Patent Literature 1, the contact area between the corrugated fin and the flat heat-transfer tube reduces, and thus the heat exchange efficiency may be lowered. 
         [0007]    The present invention has been made as a challenge to solve such a problem described above, and has an object to provide a heat exchanger in which drainage performance of the tube and the fin is improved while preventing reduction in heat exchange efficiency. 
       Solution to Problem 
       [0008]    In order to meet the challenge as described above, according to the present invention, there is provided a heat exchanger, including: a tube having surfaces opposed to each other at a predetermined interval; and a fin including a bent portion and a flat portion which are alternately formed in a longitudinal direction, the bent portion being joined to the opposing surfaces of the tube, in which the fin has a predetermined lateral range in the bent portion which is brought into contact with one of the opposing surfaces, the predetermined lateral range being bent toward another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming a communication path. Further, the fin is provided with longitudinal cutting lines within the predetermined lateral range of the bent portion so that a part formed by the longitudinal cutting lines is bent toward the another of the opposing surfaces and joined to the another of the opposing surfaces, thereby forming the communication path. Further, the communication path is provided in each of the bent portion which is brought into contact with the one of the opposing surfaces, and the bent portion which is brought into contact with the another of the opposing surfaces. Further, the communication path provided in the bent portion which is brought into contact with the one of the opposing surfaces has a lateral range which overlaps with a lateral range of the communication path provided in the bent portion which is brought into contact with the another of the opposing surfaces. 
         [0009]    According to the present invention, it is possible to provide the heat exchanger in which drainage performance of the tube and the fin is improved while preventing reduction in heat exchange efficiency. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0010]      FIG. 1  is a schematic front view of a heat exchanger according to an embodiment of the present invention. 
           [0011]      FIG. 2  is a perspective view of a fin of the heat exchanger according to the embodiment of the present invention. 
           [0012]      FIG. 3  is a perspective view of a fin of the heat exchanger according to the embodiment of the present invention. 
           [0013]      FIG. 4(   a ) is a plan view of the fin of the heat exchanger according to the embodiment of the present invention. 
           [0014]      FIG. 4(   b ) is a side view of the same. 
           [0015]      FIG. 4(   c ) is a sectional view taken along the line A-A of  FIG. 4(   a ). 
           [0016]      FIG. 5  is a perspective view of a fin of a heat exchanger according to another embodiment of the present invention. 
           [0017]      FIG. 6(   a ) is a plan view of the fin of the heat exchanger according to the another embodiment of the present invention. 
           [0018]      FIG. 6(   b ) is a side view of the same. 
           [0019]      FIG. 6(   c ) is a sectional view taken along the line B-B of  FIG. 6(   a ). 
           [0020]      FIG. 7  is a perspective view of a fin of a heat exchanger according to further another embodiment of the present invention. 
           [0021]      FIG. 8(   a ) is a plan view of the fin of the heat exchanger according to the further another embodiment of the present invention. 
           [0022]      FIG. 8(   b ) is a side view of the same. 
           [0023]      FIG. 8(   c ) is a sectional view taken along the line C-C of  FIG. 8(   a ). 
           [0024]      FIG. 8(   d ) is a sectional view taken along the line D-D of  FIG. 8(   a ). 
           [0025]      FIG. 9  is a configuration view illustrating an example of an air conditioning apparatus including the heat exchangers. 
           [0026]      FIG. 10(   a ) is a schematic view illustrating a modified example of the fin. 
           [0027]      FIG. 10(   b ) is a schematic view illustrating another modified example of the fin. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0028]    In the following, embodiments of the present invention are specifically described with reference to the drawings. For the sake of convenience, parts having the same action and effect are denoted by the same reference symbols, and description thereof is omitted herein. 
       First Embodiment 
       [0029]    As illustrated in  FIG. 1 , a heat exchanger  100  includes a plurality of tubes  110  arranged in parallel to each other, through which a refrigerant flows, and fins  120  each joined by brazing between adjacent tubes  110 . In the illustrated example, the plurality of tubes  110  are communicated to hollow header tanks  130  and  135  at both ends of the plurality of tubes  110  in their longitudinal direction (refrigerant flowing direction). The header tank  130  provided on the upper side includes a refrigerant entrance portion  130   a  provided on one end side, a refrigerant exit portion  130   b  provided on the other end side, and a part it ion plate  131  provided at a center thereof, for partitioning inside of the header tank  130 . With this, the refrigerant flowing in from the entrance portion  130   a  of the header tank  130  flows through the tubes  110  (two tubes on the left side in  FIG. 1 ) communicated on the entrance portion  130   a  side with respect to the partition plate  131 , and flows into the header tank  135  provided on the lower side. Then, the refrigerant exits from the header tank  135  to flow through the tubes  110  (two tubes on the right side in  FIG. 1 ) communicated on the exit portion  130   b  side with respect to the partition plate, and flows out from the exit portion  130   b  via the header tank  130 . Note that,  FIG. 1  schematically illustrates the heat exchanger  100 , and is simplified for the sake of easy understanding of the description. 
         [0030]    As illustrated in  FIG. 2 , the tube  110  is formed into a flat hollow plate shape and is made of a metal having high heat conductivity, such as aluminum. Further, in an inside space, a plurality of partition portions  113  are provided so that a plurality of flow paths  111  extending in a longitudinal direction are arranged in parallel in a lateral direction (width direction). As illustrated in  FIG. 1 , the plurality of tubes  110  are equally arranged in parallel at predetermined intervals so that flat surfaces  115  thereof are opposed to each other, and the fin  120  is joined to the opposing flat surfaces  115  of the adjacent tubes  110 . The tube  110  has two longitudinal end portions  110   a  and  110   b , which are inserted into insertion holes provided in the header tanks  130  and  135 , respectively, and are brazed. 
         [0031]    As illustrated in  FIGS. 3 and 4 , the fin  120  is a so-called corrugated fin, and includes a flat portion  121  having a flat plate shape and a bent portion  122  bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion  122  is a part to be joined to the flat surface  115  of the tube  110 , and includes a first bent portion  122   a  to be joined to the flat surface  115  of one of the opposing tubes  110 , and a second bent portion  122   b  to be joined to the flat surface  115  of the other of the opposing tubes  110  (see  FIG. 1 ). In the illustrated example, the flat portion  121  is smoothly and continuously provided to the bent portion  122  ( 122   a  and  122   b ) formed into a semi-circular arc shape in cross section. With this, adjacent flat portions  121  are provided in parallel to each other. Further, when the fin  120  is joined to the tube  110 , the flat portion  121  becomes perpendicular to the longitudinal direction of the tube  110 . Note that, similarly to the tube, the fin  120  is made of a metal having high heat conductivity, such as aluminum. 
         [0032]    In a predetermined range (near the center in the illustrated example, and as illustrated in  FIG. 4(   a ), observed as a cutout in plan view) in the lateral direction (width direction) of the first bent portion  122   a , two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion  121  continuous with the first bent portion  122   a . Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion  121  so as to be protruded on a side opposite to the side on which the first bent portion  122   a  is protruded. In this manner, a third bent portion  122   c  is formed. The third bent portion  122   c  formed by the two cutting lines extends up to a position of the second bent portion  122   b  so as to be joined to the flat surface  115  of the other of the opposing tubes  110 . 
         [0033]    As illustrated in  FIG. 4(   b ), the third bent portion  122   c  has a curvature radius smaller than the curvature radius of the first bent portion  122   a  and the second bent portion  122   b , and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion  123  in the flat portion  121 . Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion  121 , but the length may be changed as appropriate so that the third bent portion  122   c  can be joined to the flat surface  115  of the other of the opposing tubes  110 , depending on the curvature radius of the third bent portion  122   c  and the curvature radius of the bent-back portion  123  in the flat portion  121 . 
         [0034]    As described above, the third bent portion  122   c  is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion  122   a , and thus a communication path  125  (indicated by an arrow in  FIG. 3 ) is formed along the longitudinal direction of the tube  110  in a predetermined lateral range (width of the third bent portion) on the first bent portion  122   a  side. With this, condensed water accumulated inside the fin  120  or between the fin  120  and the tube  110  may be easily drained downward through the communication path  125 . 
         [0035]    Further, as illustrated in  FIG. 1 , the first bent portion  122   a  is joined by brazing to the surface of the one of the opposing tubes  110 , and the second bent portion  122   b  and the third bent portion  122   c  are joined by brazing to the surface of the other of the opposing tubes  110 . With this, the total contact area of the fin  120  with respect to the pair of opposing tubes  110  and  110  is equivalent in both the case where the third bent portion  122   c  is provided and the case where the third bent portion  122   c  is not provided, and thus reduction in heat exchange efficiency can be prevented. 
       Second Embodiment 
       [0036]      FIGS. 5 and 6  illustrate a fin  220  of a heat exchanger  200  according to a second embodiment of the present invention. Note that, the heat exchanger  200  of the second embodiment has a configuration in which the fin  220  has a structure different from that of the fin  120  of the heat exchanger  100  of the first embodiment. Therefore, description other than that of the fin  220  is omitted herein. 
         [0037]    As illustrated in  FIGS. 5 and 6 , the fin  220  is a so-called corrugated fin, and includes a flat portion  221  having a flat plate shape and a bent portion  222  bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion  222  is a part to be joined to the flat surface  115  of the tube  110 , and includes a first bent portion  222   a  to be joined to the flat surface  115  of one of the opposing tubes  110 , and a second bent portion  222   b  to be joined to the flat surface  115  of the other of the opposing tubes  110 . In the illustrated example, the flat portion  221  is smoothly and continuously provided to the bent portions  222   a  and  222   b  formed into a semi-circular arc shape in cross section. With this, adjacent flat portions  221  are provided in parallel to each other. Further, when the fin  220  is joined to the tube  110 , the flat portion  221  becomes perpendicular to the longitudinal direction of the tube  110 . Note that, similarly to the tube, the fin  220  is made of a metal having high heat conductivity, such as aluminum. 
         [0038]    In a predetermined range (near the center in the illustrated example) in the lateral direction of the first bent portion  222   a , two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion  221  continuous with the first bent portion  222   a . Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion  221  so as to be protruded on a side opposite to the side on which the first bent portion  222   a  is protruded. In this manner, a third bent portion  222   c  is formed. The third bent portion  222   c  formed by the two cutting lines extends up to a position of the second bent portion  222   b  so as to be joined to the flat surface  115  of the other of the opposing tubes  110 . 
         [0039]    Further, in a predetermined range in the lateral direction of the second bent portion  222   b , which is larger than and overlapped with the range in the lateral direction of the third bent portion  222   c , two cutting lines along the longitudinal direction are provided up to the intermediate position of the flat portion  221  continuous with the second bent portion  222   b . Then, the fin  220  within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion  221  so as to be protruded on a side opposite to the side on which the second bent portion  222   b  is protruded. In this manner, a fourth bent portion  222   d  is formed. The fourth bent portion  222   d  formed by the two cutting lines extends up to a position of the first bent portion  222   a  so as to be joined to the flat surface  115  of the one of the opposing tubes  110 . 
         [0040]    As illustrated in  FIG. 6(   b ), the third bent portion  222   c  and the fourth bent portion  222   d  have a curvature radius smaller than the curvature radius of the first bent portion  222   a  and the second bent portion  222   b , and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion  223  in the flat portion  221 . Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion  221 , but the length is changed as appropriate depending on the curvature radius of the third bent portion  222   c  and the fourth bent portion  222   d  and the curvature radius of the bent-back portion  223  in the flat portion  221 . 
         [0041]    As described above, the third bent portion  222   c  is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion  222   a , and thus a communication path  225   a  (indicated by an arrow in  FIG. 5 ) is formed along the longitudinal direction of the tube  110  in a predetermined lateral range (width of the third bent portion  222   c ) on the first bent portion  222   a  side. With this, condensed water accumulated inside the fin  220  or between the fin  220  and the tube  110  is drained downward through the communication path  225   a . Note that, the fourth bent portion  222   d  is arranged so as to block the communication path  225   a , and hence condensed water is drained in a manner that the condensed water threads between the communication path  225   a  and the fourth bent portion  222   d.    
         [0042]    Further, the fourth bent portion  222   d  is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the second bent portion  222   b , and thus a communication path  225   b  (indicated by arrows in  FIG. 5 ) is formed along the longitudinal direction of the tube  110  in a predetermined lateral range (width of the fourth bent portion  222   d ) on the second bent portion  222   b  side. With this, condensed water accumulated inside the fin  220  or between the fin  220  and the tube  110  is drained downward through the communication path  225   b . Note that, the third bent portion  222   c  is arranged in the communication path  225   b , and hence only both sides of the communication path  225   b  are linearly communicated. 
         [0043]    Further, the first bent portion  222   a  and the fourth bent portion  222   d  are joined by brazing to the flat surface  115  of the one of the opposing tubes  110 , and the second bent portion  222   b  and the third bent portion  222   c  are joined by brazing to the flat surface  115  of the other of the opposing tubes  110 . With this, the total contact area of the fin  220  with respect to the pair of opposing tubes  110  and  110  is equivalent in both the case where the third bent portion  222   c  and the fourth bent portion  222   d  are provided and the case where the third bent portion  222   c  and the fourth bent portion  222   d  are not provided, and thus reduction in heat exchange efficiency can be prevented. 
       Third Embodiment 
       [0044]      FIGS. 7 and 8  illustrate a fin  320  of a heat exchanger  300  according to a third embodiment of the present invention. Note that, the heat exchanger  300  of the third embodiment has a configuration in which the fin  320  has a structure different from that of the fin  120  of the heat exchanger  100  of the first embodiment. Therefore, description other than that of the fin  320  is omitted herein. 
         [0045]    As illustrated in  FIGS. 7 and 8 , the fin  320  is a so-called corrugated fin, and includes a flat portion  321  having a flat plate shape and a bent portion  322  bent with a predetermined curvature radius, which are formed alternately in the longitudinal direction. The bent portion  322  is a part to be joined to the flat surface  115  of the tube  110 , and includes a first bent portion  322   a  to be joined to the flat surface  115  of one of the opposing tubes  110 , and a second bent portion  322   b  to be joined to the flat surface  115  of the other of the opposing tubes  110 . In the illustrated example, the flat portion  321  is smoothly and continuously provided to the bent portion  322  formed into a semi-circular arc shape in cross section. With this, adjacent flat portions  321  are provided in parallel to each other. Further, when the fin  320  is joined to the tube  110 , the flat portion  321  becomes perpendicular to the longitudinal direction of the tube  110 . Note that, similarly to the tube, the fin  320  is made of a metal having high heat conductivity, such as aluminum. 
         [0046]    In a predetermined range on one side (in the example illustrated in  FIG. 8(   a ), a predetermined range on the left side with respect to the center) in the lateral direction of the first bent portion  322   a , two cutting lines along the longitudinal direction are provided up to an intermediate position of the flat portion  321  continuous with the first bent portion  322   a . Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion  321  so as to be protruded on a side opposite to the side on which the first bent portion  322   a  is protruded. In this manner, a third bent portion  322   c  is formed. The third bent portion  322   c  formed by the two cutting lines extends up to a position of the second bent portion  322   b  so as to be joined to the flat surface  115  of the other of the opposing tubes  110 . 
         [0047]    Further, in a predetermined range on the other side (in the example illustrated in  FIG. 8(   a ), a predetermined range on the right side with respect to the center) in the lateral direction of the second bent portion  322   b , two cutting lines along the longitudinal direction are provided up to the intermediate position of the flat portion  321  continuous with the second bent portion  322   b . Then, the fin within the range of the two cutting lines is bent back from the longitudinal intermediate position of the flat portion  321  so as to be protruded on a side opposite to the side on which the second bent portion  322   b  is protruded. In this manner, a fourth bent portion  322   d  is formed. The fourth bent portion  322   d  formed by the two cutting lines extends up to a position of the first bent portion  322   a  so as to be joined to the flat surface  115  of the one of the opposing tubes  110 . Note that, in the illustrated example, the width of the third bent portion  322   c  and the width of the fourth bent portion  322   d  are equal to each other. 
         [0048]    As illustrated in  FIGS. 8(   b ) and  8 ( c ), the third bent portion  322   c  and the fourth bent portion  322   d  have a curvature radius smaller than the curvature radius of the first bent portion  322   a  and the second bent portion  322   b , and further, this curvature radius is substantially the same as the curvature radius of a bent-back portion  323  in the flat portion  321 . Note that, description is made of an example in which the cutting line has a length extending up to the longitudinal intermediate position of the flat portion  321 , but the length is changed as appropriate depending on the curvature radius of the third bent portion  322   c  and the fourth bent portion  322   d  and the curvature radius of the bent-back portion  323  in the flat portion. 
         [0049]    As described above, the third bent portion  322   c  is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the first bent portion  322   a , and thus a communication path  325   a  (indicated by an arrow in  FIG. 7 ) is formed along the longitudinal direction of the tube  110  in a predetermined lateral range (width of the third bent portion  322   c ) on the first bent portion  322   a  side. With this, condensed water accumulated inside the fin  320  or between the fin  320  and the tube  110  is drained downward through the communication path  325   a.    
         [0050]    Further, the fourth bent portion  322   d  is formed continuously in the longitudinal direction with respect to the predetermined lateral range of the second bent portion  322   b , and thus a communication path  325   b  (indicated by an arrow in  FIG. 7 ) is formed toward the longitudinal direction of the fin  320  in a predetermined lateral range (width of the fourth bent portion  322   d ) on the second bent portion  322   b  side. With this, condensed water accumulated inside the fin  320  or between the fin  320  and the tube  110  is drained downward through the communication path  325   b.    
         [0051]    Further, the first bent portion  322   a  and the fourth bent portion  322   d  are joined by brazing to the flat surface  115  of the one of the opposing tubes  110 , and the second bent portion  322   b  and the third bent portion  322   c  are joined by brazing to the flat surface  115  of the other of the opposing tubes  110 . With this, the total contact area of the fin  320  with respect to the pair of opposing tubes  110  is equivalent in both the case where the third bent portion  322   c  and the fourth bent portion  322   d  are provided and the case where the third bent portion  322   c  and the fourth bent portion  322   d  are not provided, and thus reduction in heat exchange efficiency can be prevented. 
         [0052]    (Usage Example) 
         [0053]    As an example in which the heat exchangers ( 100 ,  200 , and  300 ) exemplified in the above-mentioned first to third embodiments are used,  FIG. 9  illustrates an overall configuration view of an air conditioning apparatus  1  provided in an electric vehicle, for example. This air conditioning apparatus  1  utilizes a so-called heat pump cycle, and switches cooling and heating by switching, with a four-way valve  13 , the flow of the refrigerant from a compressor  11  with respect to an out-vehicle heat exchanger  100 A and an in-vehicle heat exchanger  100 B. Note that, the heat exchanger  100 A and the heat exchanger  100 B each correspond to any one of the heat exchangers  100 ,  200 , and  300 , and in this case, description is made of a case where the heat exchanger  100 A and the heat exchanger  100 B each correspond to the heat exchanger  100  of the first embodiment. 
         [0054]    In the illustrated example, the four-way valve  13  is connected to an ejection port  11   a  of the compressor  11 . With this, the compressor  11 , the in-vehicle heat exchanger  100 B, and the out-vehicle heat exchanger  100 A are connected as follows. That is, in a case where the four-way valve  13  is connected in a state as indicated by broken lines (heating operation), the refrigerant ejected from the compressor  11  flows into the in-vehicle heat exchanger  100 B, and the refrigerant that has passed through the in-vehicle heat exchanger  100 B flows into the out-vehicle heat exchanger  100 A via an expansion valve  15  so that the refrigerant returns to an intake port  11   b  of the compressor  11  via the four-way valve  13 . Further, in a case where the four-way valve  13  is connected in a state as indicated by solid lines (cooling operation), the refrigerant ejected from the compressor  11  flows into the out-vehicle heat exchanger  100 A, and the refrigerant that has passed through the out-vehicle heat exchanger  100 A flows into the in-vehicle heat exchanger  100 B via the expansion valve  15  so that the refrigerant returns to the intake port  11   b  of the compressor  11  via the four-way valve  13 . Note that, a cooling fan  17  is provided adjacent to the out-vehicle heat exchanger  100 A. 
         [0055]    In an in-vehicle unit of the air conditioning apparatus  1 , a damper  21  for intake air switching and a blower  23  are provided on an upstream side of a ventilating duct  20  provided with the heat exchanger  100 B. Further, on a downstream side of the ventilating duct  20 , a heater unit  25  for heating assistance is provided, and an amount of air passing through the heater unit  25  is adjusted by a damper  27  for discharge air switching. Outlet ports  29   a ,  29   b , and  29   c  of the ventilating duct  20  are for DEF, FACE, and FOOT, respectively, and dampers  30   a ,  30   b , and  30   c  respectively provided thereto can adjust the amount of air to be discharged from the outlet ports  29   a ,  29   b , and  29   c.    
         [0056]    In such an air conditioning apparatus  1 , even when condensed water generated through dew condensation adheres to the in-vehicle heat exchanger  100 B in the case of cooling operation, the condensed water is drained through the communication path  25  provided in the fin  120  of the heat exchanger  100 B. Further, even when condensed water adheres to the out-vehicle heat exchanger  100 A in the case of heating operation, the condensed water is drained through the communication path  25  provided in the fin  120  of the heat exchanger  100 A. 
         [0057]    The embodiments of the present invention have been described above in detail with reference to the drawings, but specific configurations are not limited to those embodiments, and the present invention also encompasses design changes and the like without departing from the gist of the present invention. Further, mutual use of technologies among the above-mentioned embodiments is possible as long as the objects, the configurations, and the like do not have particular contradictions and problems. 
         [0058]    For example, description is made of an example in which the plurality of tubes are arranged in parallel, but the present invention is not limited thereto. The present invention is widely applicable to a heat exchanger in which the flat surfaces of the tube are provided opposed to each other, and the fin is arranged between the flat surfaces. For example, the heat exchanger may have a configuration in which one tube is formed into a wave shape so that opposing flat surfaces are formed in the one tube. 
         [0059]    Further, description is made of an example in which the adjacent flat portions in the fin are provided in parallel to each other, but the present invention is not limited thereto. For example, as illustrated in  FIG. 10(   a ), adjacent flat portions  421  may be arranged with a predetermined angle. Note that, in the example of  FIG. 10(   a ), each of a first bent portion  422   a  and a second bent portion  422   b  is provided with a communication path, and condensed water may easily flow into each communication path. 
         [0060]    Further, description is made of an example in which the flat portion is provided so as to be perpendicular to the longitudinal direction of the tube, but the present invention is not limited thereto. For example, as illustrated in  FIG. 10(   b ), a position of a bent portion  522   a  joined to one of the opposing tubes  110  and a position of a bent portion  522   b  joined to the other of the opposing tubes  110  may be more shifted in a vertical direction as compared to the above-mentioned embodiments so that a flat portion  521  is inclined toward the one of the opposing tubes  110 . In this case, for example, when the communication path is provided only on the first bent portion  522   a  side, if the flat portion  521  is inclined so that the communication path side is always directed downward, the condensed water may easily flow into the communication path. 
         [0061]    Further, description is made of an example in which the communication path is provided in a lateral center in the first embodiment and the second embodiment, and the communication paths are provided in both the lateral end portions in the third embodiment, but the present invention is not limited thereto, and the communication path may be provided at any positions. Note that, when the communication path is provided at one lateral end portion, it is known that a larger amount of condensed water adheres to the end portion of the tube on the windward side, and hence it is preferred that the heat exchanger be configured so that air is blown by a fan from the one end side on which the communication path is provided. 
         [0062]    Further, description is made of an example in which the bent portion of the fin is curved smoothly with a predetermined curvature radius, but the present invention is not limited thereto. It is sufficient as long as the fin may be joined alternately to the flat surfaces of the opposing tubes. For example, the fin may be completely folded back to obtain corners, and the corners may be used for joining. Alternatively, the fin may be bent to form a rectangular shape for surface joining. 
         [0063]    Description is made of an example in which only one communication path is provided in the first bent portion or the second bent portion, but the present invention is not limited thereto, and two or more communication paths may be provided. Further, the width of the communication path described in each embodiment is merely an example, and the present invention is not limited thereto. Each embodiment does not preclude the setting of various widths for the communication path. 
         [0064]    Further, each embodiment does not preclude, for example, hydrophilic treatment processing by, for example, a silicate-containing coating on the surface of the heat exchanger. With such hydrophilic treatment processing, condensed water adhering to the fin or the tube easily runs downward, and hence the drainage performance improves. 
       REFERENCE SIGNS LIST 
       [0000]    
       
         
           
               100  heat exchanger 
               110  tube 
               115  flat surface 
               120  fin 
               121  flat portion 
               122   a  first bent portion 
               122   b  second bent portion 
               122   c  third bent portion 
               125  communication path 
               200  heat exchanger 
               220  fin 
               221  flat portion 
               222   a  first bent portion 
               222   b  second bent portion 
               222   c  third bent portion 
               222   d  fourth bent portion 
               225   a  communication path 
               225   b  communication path 
               300  heat exchanger 
               320  fin 
               321  flat portion 
               322   a  first bent portion 
               322   b  second bent portion 
               322   c  third bent portion 
               322   d  fourth bent portion 
               325   a  communication path 
               325   b  communication path