Patent Publication Number: US-11384997-B2

Title: Heat exchanger, heat exchanger unit, and refrigeration cycle apparatus

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This application is a U.S. national stage application of International Application No. PCT/JP2018/022575, filed on Jun. 13, 2018, the contents of which are incorporated herein by reference. 
     TECHNICAL FIELD 
     The present disclosure relates to a heat exchanger, a heat exchanger unit provided with the heat exchanger, and a refrigeration cycle apparatus, and particularly to a structure of a spacer that maintains an interval between fins installed on heat transfer tubes. 
     BACKGROUND 
     Some heat exchanger has been known that is provided with flat tubes, to improve heat exchange performance, that are each a heat transfer tube having a flat sectional shape with multiple holes. One example of such a heat exchanger is a heat exchanger where flat tubes are arranged at predetermined intervals from one another in the up-and-down direction with the direction of pipe axes extending in the lateral direction. In such a heat exchanger, plate-like fins are aligned in the direction of the pipe axes of the flat tubes, and heat is exchanged between air passing through between the fins and fluid flowing through the flat tubes. Some fin has been known that is provided with a fin collar at the rim of an insertion portion for the flat tube. The fin collar ensures a separation between the fins by causing the distal end of the fin collar to be in contact with the next fin. By maintaining an appropriate interval between the fins disposed next to each other, resistance against frost and drainage properties of the heat exchanger are ensured to prevent the reduction of heat exchange performance of the heat exchanger. 
     In Patent Literature 1, by raising opposite end portions, in the longitudinal direction, of the rim of an insertion portion, into which the flat tube is inserted, from the plate surface of the fin, the opposite end portions are in contact with the next fin. In Patent Literature 2, by raising a portion of the plate surface of the fin, which is a portion other than the rim of an insertion portion, the portion is caused to be in contact with the next fin. In Patent Literature 3, by raising a portion of the rim of an insertion portion for the flat tube, which is a portion that faces the long side of the section of the flat tube, the portion is caused to be in contact with the next fin. 
     PATENT LITERATURE 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 10-78295 
     Patent Literature 2: Japanese Patent No. 5177307 
     Patent Literature 3: Japanese Unexamined Patent Application Publication No. 2017-198440 
     In Patent Literature 1, by raising the opposite end portions, in the longitudinal direction, of the rim of the insertion portion, a spacer is obtained that maintains the interval between the arranged fins and hence, a standing portion formed at a portion of the rim of the insertion portion that extends along the longitudinal direction is short. The standing portion is joined to the flat tube and transfers heat to the flat tube. A problem, however, is caused in that heat exchange performance is reduced as the standing portion is short. 
     In Patent Literature 2, another spacer that maintains the interval between the arranged fins is provided to a portion other than the rim of the insertion portion. As the spacer is disposed in an air passage between the fins, a problem is caused in that ventilation resistance increases in the heat exchanger and the ventilation resistance further increases during operation under the condition that outside air has a low temperature, where frost increases from the spacer used as a base point. Not only the spacer prevents drainage of condensation water or meltwater of frost through the air passage between the fins but also a problem is caused in that heat transfer performance of the fins reduces as a hole is provided in the plate surface of the fin. 
     In Patent Literature 3, by raising the portion of the rim of the insertion portion for the flat tube, which is a portion that faces the long side of the section of the flat tube, the spacer is formed. In recent years, however, as the thickness of the flat tube has been reduced, the width of the insertion portion is small and hence, it is difficult to raise the spacer from the plate surface of the fin up to a required height. In a case where the height of the spacer from the plate surface is insufficient, the interval between the fins disposed next to each other is small. Drainage properties of condensation water may thus reduce and ventilation properties may be reduced by, for example, the clogging of the air passage when frost forms. A problem therefore is caused in that the heat exchanger does not effectively produce heat exchange performance. 
     SUMMARY 
     The present disclosure has been made to solve the above-mentioned problems, and it is an object of the present disclosure to provide a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus where deterioration in drainage properties and ventilation properties is prevented, an air passage is not easily clogged when frost forms, and both defrosting properties and heat exchange performance are achieved. 
     A heat exchanger according to one embodiment of the present disclosure includes a flat tube and a plurality of fins that are each a plate having a plate surface extending in a longitudinal direction and in a width direction orthogonal to the longitudinal direction. The plate surface intersects a pipe axis of the flat tube. The plurality of fins are arranged at an interval from one another. The plurality of fins each have an insertion portion in which the flat tube is inserted, a first spacer formed at a rim of the insertion portion and maintaining the interval, and a second spacer formed at a portion of the plate other than the rim of the insertion portion and maintaining the interval. The first spacer is positioned at one end portion in a longitudinal direction of a section of the rim of the insertion portion, and the section is perpendicular to the pipe axis of the flat tube. 
     A heat exchanger unit according to another embodiment of the present disclosure includes the above-mentioned heat exchanger, and a fan configured to send air to the heat exchanger. The above-mentioned first spacer is positioned upwind of the above-mentioned second spacer in a direction of a flow of air sent to the heat exchanger. 
     A refrigeration cycle apparatus according to still another embodiment of the present disclosure includes the above-mentioned heat exchanger unit. 
     According to an embodiment of the present disclosure, with the above-mentioned configuration, the interval between the fins is appropriately maintained. It is therefore possible to prevent the clogging of the air passage when frost forms, and drainage properties of meltwater are ensured during the defrosting process. Further, as the first spacer is positioned at an end portion of the insertion portion in the longitudinal direction of the flat tube, it is possible to prevent the reduction of ventilation properties between the fin and the flat tube. Resistance against frost and drainage properties of the heat exchanger and the heat exchanger unit are therefore enhanced while heat exchange performance is maintained. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view showing a heat exchanger according to Embodiment 1. 
         FIG. 2  is an explanatory view of a refrigeration cycle apparatus to which the heat exchanger according to Embodiment 1 is applied. 
         FIG. 3  is an explanatory view of the sectional structure of the heat exchanger shown in  FIG. 1 . 
         FIG. 4  is an enlarged sectional view of first spacers provided to fins of the heat exchanger according to Embodiment 1. 
         FIG. 5  is a plan view of a state where an insertion portion to be formed in the fin of the heat exchanger according to Embodiment 1 is yet to be formed. 
         FIG. 6  includes enlarged views of a second spacer provided to the fin of the heat exchanger according to Embodiment 1. 
         FIG. 7  is an explanatory view of a second spacer that is a comparative example of the second spacer formed on the fin of the heat exchanger according to Embodiment 1. 
         FIG. 8  includes explanatory views of a second spacer that is a modification of the second spacer formed on the fin of the heat exchanger according to Embodiment 1. 
         FIG. 9  includes explanatory views of a second spacer that is a modification of the second spacer formed on the fin of the heat exchanger according to Embodiment 1. 
         FIG. 10  is an explanatory view of the sectional structure of a heat exchanger that is a modification of the heat exchanger according to Embodiment 1. 
         FIG. 11  is an explanatory view of the sectional structure of a heat exchanger according to Embodiment 2. 
         FIG. 12  is a plan view of a state where an insertion portion to be formed in a fin of the heat exchanger according to Embodiment 2 is yet to be formed. 
         FIG. 13  is an explanatory view of the sectional structure of a heat exchanger that is a modification of the heat exchanger according to Embodiment 2. 
     
    
    
     DETAILED DESCRIPTION 
     Hereinafter, embodiments of a heat exchanger, a heat exchanger unit, and a refrigeration cycle apparatus are described. Hereinafter, the embodiments of the present disclosure are described with reference to drawings. In the drawings, components and portions given the same reference signs are the same or corresponding components and portions, and the reference signs are common in the entire specification. Further, forms of components described in the entire specification are merely examples, and the present disclosure is not limited to the description in the specification. In particular, the combination of the components is not limited to the combination in each embodiment, and components described in one embodiment may be applicable to another embodiment. Further, when it is not necessary to distinguish or specify a plurality of components or portions of the same kind that are, for example, differentiated by suffixes, the suffixes may be omitted. In the drawings, the relationship in size of the components and portions may differ from that of actual components and portions. It is noted that directions indicated by “x”, “y”, and “z” in the drawings indicate the same directions in the drawings. 
     Embodiment 1 
       FIG. 1  is a perspective view showing a heat exchanger  100  according to Embodiment 1.  FIG. 2  is an explanatory view of a refrigeration cycle apparatus  1  to which the heat exchanger  100  according to Embodiment 1 is applied. The heat exchanger  100  shown in  FIG. 1  is a heat exchanger to be mounted on the refrigeration cycle apparatus  1 , such as an air-conditioning apparatus and a refrigerator. In Embodiment 1, an air-conditioning apparatus is described as an example of the refrigeration cycle apparatus  1 . The refrigeration cycle apparatus  1  has a configuration in which a compressor  3 , a four-way valve  4 , an outdoor heat exchanger  5 , an expansion device  6 , and an indoor heat exchanger  7  are connected by a refrigerant pipe  90  to form a refrigerant circuit. In the refrigeration cycle apparatus  1 , refrigerant flows through the refrigerant pipe  90 . By switching the flows of the refrigerant by the four-way valve  4 , the operation of the refrigeration cycle apparatus  1  is switched to one of a heating operation, a refrigerating operation, and a defrosting operation. 
     The outdoor heat exchanger  5  is mounted on an outdoor unit  8 , the indoor heat exchanger  7  is mounted on an indoor unit  9 , and a fan  2  is disposed in the vicinity of each of the outdoor heat exchanger  5  and the indoor heat exchanger  7 . In the outdoor unit  8 , the fan  2  sends outside air into the outdoor heat exchanger  5  to exchange heat between the outside air and refrigerant. In the indoor unit  9 , the fan  2  sends indoor air into the indoor heat exchanger  7  to exchange heat between the indoor air and refrigerant, so that the temperature of the indoor air is conditioned. Further, in the refrigeration cycle apparatus  1 , the heat exchanger  100  may be used as the outdoor heat exchanger  5 , mounted on the outdoor unit  8 , or as the indoor heat exchanger  7 , mounted on the indoor unit  9 , and the heat exchanger  100  is used as a condenser or an evaporator. In the specification, a unit, such as the outdoor unit  8  and the indoor unit  9 , on which the heat exchanger  100  is mounted is particularly referred to as “heat exchanger unit”. 
     The heat exchanger  100  shown in  FIG. 1  includes two heat exchange parts  10 ,  20 . The heat exchange parts  10 ,  20  are arranged in series along the x direction shown in  FIG. 1 . The x direction is a direction perpendicular to a direction along which flat tubes  30  of the heat exchange part  10  are arranged in parallel and to a direction along which the pipe axes of the flat tubes  30  extend. In Embodiment 1, air flows into the heat exchanger  100  along the x direction. The heat exchange parts  10 ,  20  are consequently arranged in series along a direction along which air flows through the heat exchanger  100 . The first heat exchange part  10  is disposed upwind, and the second heat exchange part  20  is disposed downwind. Headers  70 ,  71  are disposed at both ends of the heat exchange part  10 , and the header  70  and the header  71  are connected with each other by the flat tubes  30 . The header  70  and a header  72  are disposed at both ends of the heat exchange part  20 , and the header  70  and the header  72  are connected with each other by the flat tubes  30 . Refrigerant flowing into the header  71  from a refrigerant pipe  91  passes through the heat exchange part  10 , flows into the heat exchange part  20  through the header  70 , and flows out to a refrigerant pipe  92  from the header  72 . The heat exchange part  10  and the heat exchange part  20  may have the same structure, or may have different structures. 
       FIG. 3  is an explanatory view of the sectional structure of the heat exchanger  100  shown in  FIG. 1 .  FIG. 3  is an explanatory view showing a portion of a section A of the heat exchange part  10  of the heat exchanger  100  shown in  FIG. 1  as the section A perpendicular to the y axis is viewed from the y direction. The heat exchange part  10  has a configuration in which the plurality of flat tubes  30  are arranged in parallel in the z direction with the pipe axes of the flat tubes  30  extending in the y direction. Refrigerant flows through the flat tubes  30 , so that heat is exchanged between air sent into the heat exchanger  100  and the refrigerant flowing through the flat tubes  30 . Further, fins  40  are attached to the flat tubes  30  with a plate surface  48  of each fin  40 , which is a plate, intersecting the pipe axes of the flat tubes  30 . The fin  40  has a rectangular shape having the longitudinal direction of the fin  40  extending in a direction along which the flat tubes  30  are arranged in parallel. In other words, the fin  40  is provided with the longitudinal direction of the fin  40  extending along the z direction. The fin  40  is provided with an insertion portion  44  in which the flat tube  30  is inserted. In Embodiment 1, the insertion portion  44  is a long hole opened in the plate surface  48  of the fin  40 . The flat tubes  30  are fitted in these insertion portions  44 . 
     The width direction of the fin  40  means a direction perpendicular to the longitudinal direction of the fin  40 , and extends along the x direction shown in  FIG. 3 . In Embodiment 1, air sent into the heat exchanger  100  flows in the x direction shown in  FIG. 3 , and an arrow C indicates the flow of air. The fin  40  includes a first end edge  41 , which is one end edge in the width direction of the fin  40 , positioned upwind in the direction of the flow of air and a second end edge  42 , which is the other end edge in the width direction of the fin  40 , positioned downwind in the direction of the flow of air. The insertion portion  44  is a long hole opened in the plate surface  48  and has the longitudinal direction of the long hole extending parallel to the width direction of the fin  40 . The flat tube  30  also has the longitudinal axis of a section of the flat tube  30  perpendicular to the pipe axis extending parallel to the width direction of the fin  40 . 
     The plurality of fins  40  are arranged along a direction along which the pipe axes of the flat tubes  30  extend. The fins  40  disposed next to each other are disposed with a predetermined gap between the plate surfaces  48  so that air is allowed to pass through between the plate surfaces  48 . To ensure an interval between the fins  40  disposed next to each other, a first spacer  50  and a second spacer  60  are formed on the fins  40 . Hereinafter, the first spacer  50  and the second spacer  60  may be collectively referred to as “spacer”. The spacer is formed by bending a portion of the fin  40 , which is a plate, and the spacer is erected in a direction intersecting the plate surface  48 . 
       FIG. 4  is an enlarged sectional view of the first spacers  50  provided to the fins  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 4  corresponds to section A-A of the fin  40  shown in  FIG. 3  and also includes the next fin  40 . In  FIG. 4 , the flat tubes  30  are omitted. At an end portion  46   a  of the insertion portion  44  close to the first end edge  41 , the first spacer  50  is erected toward the next fin  40 , and the distal end of the first spacer  50  is in contact with a plate surface  48   b  of the next fin  40 . The distal end of the first spacer  50  is bent to form a contact portion  52 . In Embodiment 1, a standing surface  53  of the first spacer  50  is arc-shaped. However, the shape is not limited to an arc. For example, the standing surface  53  may be raised substantially perpendicular to a plate surface  48   a  and linearly formed. 
     As shown in  FIG. 4 , at a long side  47   a  in the rim of the insertion portion  44 , a standing piece  45  is formed. The height of the standing piece  45  is lower than the height of the first spacer  50 . The standing piece  45  is in contact with a side surface of the flat tube  30  that extends along the longitudinal axis of the section of the flat tube  30  and transfers heat between the fin  40  and the flat tube  30 . The standing piece  45  and the flat tube  30  are joined by, for example, brazing. At a long side  47   b  shown in  FIG. 3 , a standing piece  45  is also formed similarly to the long side  47   a . The long side  47   b  is formed symmetrically to the long side  47   a  across the center line extending along the longitudinal direction of the insertion portion  44 . 
       FIG. 5  is a plan view of a state where the insertion portion  44  to be formed in the fin  40  of the heat exchanger  100  according to Embodiment 1 is yet to be formed. The insertion portion  44  is formed by raising tongue-shaped pieces obtaining by making cuts in the fin  40 , which is a plate, in the normal direction of the plate surface  48   a . The first spacer  50  is formed by raising a tongue-shaped piece  150  extending from one end close to the first end edge  41  to the other end close to the second end edge  42 . The length L 1  of the tongue-shaped piece  150  is set corresponding to the distance between the fins  40  of the heat exchanger  100 . As the tongue-shaped piece  150  is shaped in such a manner that the tongue-shaped piece  150  extends in the longitudinal direction of the insertion portion  44 , even in a case where the transverse axis of the flat tube  30  fitted in the insertion portion  44  is small, it is possible to set the tongue-shaped piece  150  to be long along the long sides  47   a ,  47   b . Even in a case where the flat tube  30  is thin, the interval between the fins  40  may therefore be set to be large. Further, the width W 1  of the tongue-shaped piece  150  is the width of the short side of the insertion portion  44  and is set in such a manner that it is possible to fit the flat tube  30  into the insertion portion  44 . 
     The standing piece  45  formed to extend along each of the long sides  47   a ,  47   b  of the insertion portion  44  is formed by raising, from the plate surface  48 , the corresponding one of tongue-shaped pieces  145   a ,  145   b  formed at a portion other than a portion in which the tongue-shaped piece  150  is formed. The tongue-shaped pieces  145   a ,  145   b  each extend in the longitudinal direction of the fin  40  and are each formed long in the width direction of the fin  40  to have the width W 2 . In  FIG. 5 , the tongue-shaped pieces  145   a ,  145   b  are each formed in a length of W 1 / 2 , which is a half of the short side of the insertion portion  44 . As the length obtaining by adding the length L 2  of the tongue-shaped piece  145   a  and the length L 2  of the tongue-shaped piece  145   b  is at maximum the same length of the width W 1  of the short side of the insertion portion  44 , in the heat exchanger  100  according to Embodiment 1, the length L 1  of the tongue-shaped piece  150 , which is settable to be large, is adjusted in such a manner that the first spacer  50  is caused to be in contact with the next fin  40 , to appropriately ensure the interval between fins  40 . 
       FIG. 6  includes enlarged views of the second spacer  60  provided to the fin  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 6 ( a )  is an enlarged view as the second spacer  60  is viewed from the direction indicated by the arrow C in  FIG. 3 , and is an enlarged view as the second spacer  60  is viewed from a direction parallel to the plate surfaces  48  of the fins  40  and parallel to a standing surface  63  of the second spacer  60 .  FIG. 6 ( b )  is an explanatory view of the structure of the second spacer  60  as the second spacer  60  is viewed from a direction perpendicular to a section taken along B-B in  FIG. 6 ( a ) . The second spacer  60  is formed by bending a portion of the fin  40 , which is a plate, and the second spacer  60  is erected in a direction intersecting the plate surface  48 . The second spacer  60  is erected toward the next fin  40 , and the distal end of the second spacer  60  is in contact with the plate surface  48   b  of the next fin  40 . That is, the height of the second spacer  60  from the plate surface  48   a  to the distal end of the second spacer  60  is equally set as the height of the first spacer  50 . The distal end of the second spacer  60  is bent to form a contact portion  62 . In Embodiment 1, the standing surface  63  of the second spacer  60  is formed substantially perpendicular to the plate surface  48  of the fin  40 . The second spacer  60  is formed by bending a portion of the fin  40  in a direction intersecting the plate surface  48 . An opening port  61  is formed adjacent to the second spacer  60  in the opposite direction of the z direction of the second spacer  60 . 
       FIG. 7  is an explanatory view of a second spacer  160   c  that is a comparative example of the second spacer  60  formed on the fin  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 7  is an explanatory view as the second spacer  160   c  is viewed in the same direction as  FIG. 6 ( b ) . The second spacer  160   c  of the comparative example is formed by bending a portion of a fin  140  in the opposite direction of the z direction in  FIG. 7 . In other words, when the heat exchanger  100  is installed with the opposite direction of the z direction in  FIG. 7  aligning with the direction of gravity, the second spacer  160   c  is formed by bending the portion of the fin  140  in the direction of gravity. A standing surface  163   c  is formed substantially perpendicular to the plate surface  48 . In this case, an opening port  161   c  is formed over the second spacer  160   c . When condensation water or meltwater of frost flows down to the second spacer  160   c , not only water stays on the standing surface  163   c , but also water adheres to the edge of the opening port  161   c  because of capillarity. Further, water drops also adhere to a portion under the second spacer  160   c  in such a manner that the water drops hang from the portion under the second spacer  160   c , so that the second spacer  160   c  and the opening port  161   c  maintain water in a region surrounded by a dotted line  180  in  FIG. 7 . In contrast, water drops adhere to the second spacer  60  and the opening port  61  according to Embodiment 1 in such a manner that the water drops hang from a portion under the second spacer  60  as shown by a dotted line  80  in  FIG. 6 ( b ) . The amount of water maintained at the second spacer  60  and the opening port  61  is consequently small compared with that maintained at the second spacer  160  and the opening port  161  of the comparative example. In other words, the second spacer  60  and the opening port  61  according to Embodiment 1 maintains less amount of water and has higher drainage properties compared with the second spacer  160  and the opening port  161  of the comparative example. 
     As shown in  FIG. 3 , in Embodiment 1, the second spacer  60  is provided in an intermediate region  43  between two flat tubes  30 . In the width direction of the fin  40 , the second spacer  60  is positioned close to the second end edge  42  and the first spacer  50  is positioned close to the first end edge  41 . In addition, the first spacer  50  and the second spacer  60  are positioned away from each other across a line I. The line I passes through the center of gravity of the fin  40  as the fin  40  is viewed from the y direction and extends parallel to the longitudinal direction of the fin  40 . In the specification, the line I is referred to as “gravity center axis”. In other words, the gravity center axis intersects an imaginary line connecting the first spacer  50  and the second spacer  60 . With this configuration, the fins  40  are stably stacked on one another and an advantageous effect is obtained that the assembly workability increases in assembling the heat exchanger  100 . In addition, the first spacer  50  and the second spacer  60  are disposed with an interval between the first spacer  50  and the second spacer  60  in the width direction of the fin  40  and hence, the interval between the fins  40  is stably ensured. 
     In addition, one second spacer  60  is disposed in the intermediate region  43  between the flat tubes  30  disposed next to each other in  FIG. 3 , the second spacer  60 , however, is not always required to be disposed in each of all the intermediate regions  43 . By lessening the number of the second spacers  60  disposed to be smaller than the number of the first spacers  50  disposed, ventilation properties of the heat exchanger  100  are increased and the interval between the fins  40  disposed next to each other is stably ensured. 
     The first spacer  50  is positioned upwind of the second spacer  60  in the direction of the flow of air flowing in in the x direction. The difference in temperature between air passing through the heat exchanger  100  and a region close to the first end edge  41  of the fin  40  positioned upwind in the direction of the flow of air is larger than the difference in temperature between air passing through the heat exchanger  100  and a region close to the second end edge  42  of the fin  40  positioned downwind in the direction of the flow of air. At the region close to the first end edge  41 , heat is therefore easily exchanged between the fin  40  and the air. As the second spacer  60  is positioned in a region other than the region close to the first end edge  41  of the fin  40 , where heat is thus easily exchanged, even with the second spacer  60  disposed, the reduction of heat exchange performance of the heat exchanger  100  is prevented. Further, in a case where the heat exchanger  100  is operated as an evaporator under the condition that outside air has a low temperature, frost easily forms on an upwind portion of the heat exchanger  100 , where the difference in temperature between the upwind portion and air is large. By disposing the second spacer  60  downwind of the first spacer  50 , increase of frost from the second spacer  60  used as a base point is prevented and the interval between the fins  40  is appropriately ensured. It is therefore possible to prevent the reduction of ventilation properties of the heat exchanger  100  and appropriately ensure heat exchange performance of the heat exchanger  100 . 
     When the fin  40  is viewed in the y direction, that is, when the fin  40  is viewed in a direction perpendicular to the plate surface  48 , the standing surface  63  of the second spacer  60  extends parallel to the width direction of the fin  40 . The configuration, however, is not limited to the above-mentioned configuration. The standing surface  63  of the second spacer  60  may be inclined. In this case, as condensation water or meltwater of frost flowing down from an upper portion of the fin  40  flows from the standing surface  63  in the direction of gravity, stagnation of water on the standing surface  63  is prevented to obtain an advantageous effect that drainage properties of the heat exchanger  100  increases. 
     In addition, the width W 3  of the second spacer  60  may be smaller than the width W 1  of the first spacer  50 . As the width of the standing surface  63  of the second spacer  60  is small, ventilation resistance between the fins  40  of the heat exchanger  100  reduces and ventilation properties of the heat exchanger  100  are therefore increased. In addition, as the opening port  61  in the plate surface  48  of the fin  40  is also small, it is possible to prevent the reduction of heat exchange performance. 
     The second spacer  60  may be disposed in a region between second end portions  32  and the second end edge  42  of the fin  40 , and each second end portion  32  of the flat tube  30  is disposed downwind in the width direction of the fin  40 . By disposing the second spacer  60  further downwind than is the flat tube  30 , it is possible to prevent the reduction of heat exchange performance of the heat exchanger  100  caused by the provision of the second spacer  60 . 
     &lt;Modification of Second Spacer  60 &gt; 
       FIG. 8  includes explanatory views of a second spacer  160   a  that is a modification of the second spacer  60  formed on the fin  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 8 ( a )  corresponds to  FIG. 6 ( a ) , and  FIG. 8 ( b )  corresponds to  FIG. 6 ( b ) . The second spacer  60  provided to the fins  40  of the heat exchanger  100  according to Embodiment 1 may have the structure of the second spacer  160   a  as shown in  FIG. 8 , for example. The second spacer  160   a  is formed in such a manner that two slits are formed in a plate surface  148   a  of the fin  140 , and a portion between these slits is caused to protrude from the plate surface  148   a . The second spacer  160   a  is consequently connected with the plate surface  148   a  at two positions. In  FIG. 8 , an upper surface of the second spacer  160   a  is a standing surface  163   a . In the same manner as the standing surface  63  of the second spacer  60 , the standing surface  163   a  extends parallel to the width direction of the fin  140  when the standing surface  163   a  is viewed in the y direction. 
       FIG. 9  includes explanatory views of a second spacer  160   b  that is a modification of the second spacer  60  formed on the fin  40  of the heat exchanger  100  according to Embodiment 1.  FIG. 9 ( a )  corresponds to  FIG. 6 ( a ) , and  FIG. 9 ( b )  corresponds to  FIG. 6 ( b ) . The second spacer  160   b  is formed in such a manner that the second spacer  160   b  is caused to protrude from a plate surface  148   b  of the fin  140  in a rectangular shape. In  FIG. 9 , an upper surface of the second spacer  160   b  is a standing surface  163   b . In the same manner as the standing surface  53  of the second spacer  60 , the standing surface  163   b  extends parallel to the width direction of the fin  140  when the standing surface  163   b  is viewed in the y direction. 
     &lt;Advantageous Effects of Embodiment 1&gt; 
     In the heat exchanger  100  according to Embodiment 1, as the first spacer  50  is disposed at the end portion  46   a  in the longitudinal direction in the rim of the insertion portion  44  provided to the fin  40 , it is possible to suitably set the height of the first spacer  50  from the plate surface  48  to the distal end of the first spacer  50 . For example, even in the case where the transverse axis of the flat tube  30  is short, as the height of the first spacer  50  is ensured, it is possible to appropriately ensure the interval between the fins  40 . The reduction of the amount of refrigerant filled in the refrigeration cycle apparatus  1  is required to reduce global warming. As it is possible to set the transverse axis of the flat tube  30  to have a small value, the heat exchanger  100  is effective to reduce the amount of filled refrigerant. 
     The first spacer  50  is disposed upwind of a first end portion  31  of the flat tube  30 . No possibility consequently remains that ventilation properties of the air passage between the fins  40  are impaired. It is therefore possible to appropriately ensure a gap between the fins  40  by the first spacer  50  while ventilation resistance between the fins  40  is not increased. 
     As the first spacer  50  is disposed only at the end portion  46   a , which is one end portion of the insertion portion  44  in the longitudinal direction, it is possible to dispose the standing piece  45  at a portion other than the vicinity of the end portion  46   a . It is therefore possible to set an area on which the flat tube  30  and the standing piece  45  are in contact with each other to be large compared with a case where the first spacer  50  is disposed at each of the opposite end portions of the insertion portion  44  in the longitudinal direction. Heat transfer between the flat tube  30  and the fin  40  is consequently facilitated and heat exchange performance of the heat exchanger  100  increases. 
       FIG. 10  is an explanatory view of the sectional structure of a heat exchanger  100   a  that is a modification of the heat exchanger  100  according to Embodiment 1. The longitudinal axis of the flat tube  30  in the heat exchanger  100  according to Embodiment 1 may be disposed and inclined to the width direction of the fin  40 . As shown in  FIG. 10 , the first end portion  31  positioned closer to the first end edge  41  of the fin  140  than is the second end portion  32  is positioned lower than is the second end portion  32  positioned closer to the second end edge  42  than is the first end portion  31 . In this case, an insertion portion  144  disposed in the fin  140  is also disposed and inclined to the width direction of the fin  140  by the inclination angle θ. A second spacer  160  is also disposed and inclined by the inclination angle θ. With such a configuration, water flowing down from an upper portion of the fin  140  is easily drained from an upper surface of the flat tube  30  and an upper surface of the second spacer  160  to improve drainage properties of the heat exchanger  100   a . In addition, the insertion portion  144  and the second spacer  160  are inclined in the same direction. With such a configuration, it is possible to dispose the second spacer  60  while ventilation resistance of the air passage between the flat tubes  30  disposed next to each other is not increased. 
     The description has been made above for a state where air flows into the heat exchanger  100   a  from a direction perpendicular to the first end edge  41  of the fin  140  of the heat exchanger  100   a . However, there may be also a case where the heat exchanger  100   a  is disposed and inclined to the direction of gravity, for example. In Embodiment 1, the direction of gravity extends downward along the z axis. The heat exchanger  100 ,  100   a , however, may be disposed to have the z axis inclined to the direction of gravity. The inclination angle of each of the flat tubes  30  and the second spacer  60  is only required to be suitably set corresponding to an environment where the heat exchanger  100 ,  100   a  is disposed. 
     The second spacer  60  may be disposed in a shielded region  145 . The shielded region  145  is, within an intermediate region  143  between two insertion portions  144  of the heat exchanger  100   a , a region between an imaginary line p and a lower surface of the flat tube  30 . The imaginary line p is drawn horizontal to the width direction of the fin  140  from a lower end of the first end portion  31  of the flat tube  30 . When air flows into the heat exchanger  100   a  across the first end edge  41  of the fin  140  in the x direction, the shielded region  145  is a region shielded by the flat tube  30  disposed and inclined. In a case where the flat tube  30  is disposed as shown in  FIG. 10 , air flowing over the upper surface of the flat tube  30  flows along the upper surface of the flat tube  30  as illustrated by an arrow r shown in  FIG. 10 . The direction of air flowing under the lower surface of the flat tube  30 , however, is not easily changed as illustrated by an arrow q shown in  FIG. 10 , so that the shielded region  145  is a region where the flow of air stagnates. As the second spacer  160  is disposed in the shielded region  145 , ventilation properties of the air passage between the fins  140  are therefore less affected. 
     Embodiment 2 
     A heat exchanger  200  according to Embodiment 2 is a heat exchanger obtained by changing the structure of the insertion portion  44  from that in the heat exchanger  100  according to Embodiment 1. The description of the heat exchanger  200  according to Embodiment 2 is made below mainly for points different from Embodiment 1. In the drawings, portions of the heat exchanger  200  according to Embodiment 2 having the same functions as those in Embodiment 1 are given the same reference signs as used in the drawings for describing Embodiment 1. 
       FIG. 11  is an explanatory view of the sectional structure of the heat exchanger  200  according to Embodiment 2.  FIG. 11  is an explanatory view showing a portion of a section A of the heat exchange part  10  of the heat exchanger  200  shown in  FIG. 1  as the section A perpendicular to the y axis is viewed from the y direction. In Embodiment 2, insertion portions  244  are disposed in a fin  240 , which is a plate, included in the heat exchange part  10 . The insertion portions  244  are each a cut-out in a second end edge  242  of the fin  240 . The flat tubes  30  are fitted in these cut-outs. The insertion portion  244  has the longitudinal direction extending parallel to the width direction of the fin  240 . The flat tube  30  also has the longitudinal axis of a section of the flat tube  30  perpendicular to the pipe axis extending parallel to the width direction of the fin  240 . 
     The first spacer  50  provided to the fin  240  of the heat exchanger  200  according to Embodiment 2 has the same structure as that of the heat exchanger  100  shown in  FIG. 4 .  FIG. 4  corresponds to section A-A shown in  FIG. 11 . Long side portions  247   a ,  247   b  are in the rim of the insertion portion  244 , and a standing piece  245  is formed at the each of the long side portions  247   a ,  247   b , similarly to Embodiment 1. The height of the standing piece  245  is lower than the height of the first spacer  50 . The standing piece  245  is in contact with a side surface of the flat tube  30  that extends along the longitudinal axis of the section of the flat tube  30  and transfers heat between the fin  240  and the flat tube  30 . The standing piece  245  and the flat tube  30  are joined by, for example, brazing. 
       FIG. 12  is a plan view of a state where the insertion portion  244  to be formed in the fin  240  of the heat exchanger  200  according to Embodiment 2 is yet to be formed. The insertion portion  244  is formed by raising tongue-shaped pieces obtaining by making cuts in the fin  240 , which is a plate, in the normal direction of the plate surface  48 . The first spacer  50  is formed by raising the tongue-shaped piece  150  extending from one end close to the first end edge  41  to the other end close to the second end edge  242 . 
     The standing piece  245  formed to extend along each of the long side portions  247   a ,  247   b  of the insertion portion  244  is the corresponding one of tongue-shaped pieces  245   a ,  245   b  formed at a portion other than a portion in which the tongue-shaped piece  150  is formed. The tongue-shaped pieces  245   a ,  245   b  each extend in the longitudinal direction of the fin  240  and are each formed long in the width direction of the fin  240  to have the width W 2 . In  FIG. 12 , the tongue-shaped pieces  245   a ,  245   b  are each formed in a length of W 1 / 2 , which is a half of the short side of the insertion portion  244 . As the length obtaining by adding the length L 2  of the tongue-shaped piece  245   a  and the length L 2  of the tongue-shaped piece  245   b  is at maximum the same length of the width W 1  of the short side of the insertion portion  244 , in the heat exchanger  200  according to Embodiment 2, the length L 1  of the tongue-shaped piece  150 , which is settable to be large, is adjusted in such a manner that the first spacer  50  is caused to be in contact with the next fin  240 , to appropriately ensure the interval between the fins  240 . 
     &lt;Advantageous Effects of Embodiment 2&gt; 
     In the heat exchanger  200  according to Embodiment 2, as the first spacer  50  is disposed at the end portion  46   a  in the longitudinal direction in the rim of the insertion portion  244  provided to the fin  240 , it is possible to suitably set the height of the first spacer  50  from the plate surface  48  to the distal end of the first spacer  50 , to appropriately ensure the interval between the fins  240  disposed next to each other. In addition, as the insertion portions  244  are each a cut-out in the second end edge  242 , it is possible to insert the flat tubes  30  into the insertion portions  244  of the fin  240  from the second end edge  242 . In manufacturing the heat exchanger  200 , the fins  240  and the flat tubes  30  are easily assembled. Further, in a case where the fin  40  according to Embodiment 1 and the fin  240  according to Embodiment 2 have the same width, it is possible to set the distance between the first end portion  31  of the flat tube  30  and the first end edge  41  of the fin  240  to be larger than that of the fin  40 . In a case where the heat exchanger  200  is disposed in such a manner that the first end edge  41  of the fin  240  is disposed upwind and the refrigeration cycle apparatus  1  is operated under the condition that outside air has a low temperature, it is therefore possible to reduce frost forming in a region close to the first end edge  41  of the fin  240 . 
     In addition, similarly to Embodiment 1, the flat tube  30  in the heat exchanger  200  according to Embodiment 2 may also be inclined to the width direction of the fin  240 . In this case, the second spacer  60  may also be inclined to the width direction of the fin  240 . With such a configuration, water flowing down from the upper portion of the fin  240  is easily drained from the upper surface of the flat tube  30  and the upper surface of the second spacer  60  to improve drainage properties of the heat exchanger  200 . 
       FIG. 13  is an explanatory view of the sectional structure of a heat exchanger  200   a  that is a modification of the heat exchanger  200  according to Embodiment 2. The heat exchanger  200   a  of the modification is obtained by causing the fin  240  to extend farther in the downwind direction than the second end portions  32  of the flat tubes. As the shape of the fin  240  is caused to extend in the downwind direction, the insertion portions  244  are also formed to extend in the downwind direction. Nothing is disposed in a region of the insertion portion  244  at a portion close to the second end edge  242 . In the heat exchanger  200  according to Embodiment 2, the second end edge  242  and the second end portions  32  of the flat tubes  30  are disposed at substantially the same position in the x direction. In contrast, in the heat exchanger  200   a  of the modification, the second end edge  242  of the fin  240  is positioned away from the second end portions  32  of the flat tubes  30  in the x direction. In addition, the second spacer  60  is disposed in a region between the second end portions  32  and the second end edge  242  of the fin  240 , and each second end portion  32  of the flat tube  30  is disposed downwind in the width direction of the fin  240 . By disposing the second spacer  60  downwind of the flat tube  30 , it is possible to prevent the reduction of heat exchange performance of the heat exchanger  200   a  caused by the provision of the second spacer  60 .