Heat exchanger and refrigeration cycle device

Abstract

To provide a heat exchanger that can successfully drain droplets attached to a heat transfer tube, and a refrigeration cycle device comprising the heat exchanger.SOLUTION: A heat exchanger according to an embodiment comprises a flattened heat transfer tube, and a fin in contact with the heat transfer tube. The heat transfer tube comprises a first end part and a second end part in a width direction, and a plurality of refrigerant flow passages arranged in the width direction between the first end part and the second end part. In addition, the heat transfer tube includes an upper surface parallel to the width direction, a lower surface parallel to the upper surface, and a first curved surface located between the upper surface and the first end part in the width direction, and located above the lower surface in a thickness direction orthogonal to the upper surface and the lower surface. A distance between the first curved surface and the lower surface decreases as approaching the first end part.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] An embodiment of the present invention relates to a heat exchanger and a refrigeration cycle apparatus. [Background technology]

[0002] A heat exchanger having a plurality of flat heat transfer tubes with a refrigerant flow passage therein and a plurality of fins in contact with the heat transfer tubes is known. This type of heat exchanger is used in a refrigeration cycle device such as an air conditioner.

[0003] When a heat exchanger functions as an evaporator, liquid droplets (water droplets) generated by condensation or the like may adhere to the surface of the heat transfer tube. If these liquid droplets are not properly drained from the surface of the heat transfer tube, the heat exchange performance may decrease. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2018-523175 A Summary of the Invention [Problem to be solved by the invention]

[0005] An object of the present invention is to provide a heat exchanger capable of effectively draining liquid droplets adhering to a heat transfer tube, and a refrigeration cycle apparatus including the heat exchanger. [Means for solving the problem]

[0006] A heat exchanger according to an embodiment includes a flat heat transfer tube and a fin in contact with the heat transfer tube. The heat transfer tube has a first end and a second end in a width direction, and a plurality of refrigerant flow paths aligned in the width direction between the first end and the second end. The heat transfer tube further includes an upper surface parallel to the width direction, a lower surface parallel to the upper surface, and a first curved surface located between the upper surface and the first end in the width direction and above the lower surface in a thickness direction perpendicular to the upper surface and the lower surface. The first curved surface includes a first portion convex toward the outside of the heat transfer tube, a second portion concave toward the inside of the heat transfer tube and located between the first portion and the first end in the width direction, a third portion connecting the second portion and the lower surface; The distance between the first curved surface and the lower surface decreases toward the first end. Furthermore, the radius of curvature of the third portion is smaller than the radius of curvature of each of the first portion and the second portion.

[0007] A heat exchanger according to another aspect of the embodiment includes a flat heat transfer tube and a fin in contact with the heat transfer tube. The heat transfer tube has a first end and a second end in a width direction, and a plurality of refrigerant flow paths arranged in the width direction between the first end and the second end. The heat transfer tube further includes a flat portion having a constant thickness, a first convex portion located between the flat portion and the first end, having a first width in the width direction, and decreasing in thickness toward the first end, and a second convex portion located between the flat portion and the second end, having a second width in the width direction, and decreasing in thickness toward the second end. The first width is greater than the second width.

[0008] The refrigeration cycle device according to the embodiment includes the heat exchanger and a fan that generates an airflow passing through the heat exchanger. The first end is located downstream of the airflow from the second end. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a refrigeration cycle device according to a first embodiment. [Diagram 2]FIG. 2 is a schematic plan view of the heat exchanger according to the first embodiment. [Diagram 3] FIG. 3 is a schematic cross-sectional view of the heat exchanger taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the heat transfer tube shown in FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a heat transfer tube according to a comparative example. [Figure 6] FIG. 6 is a schematic cross-sectional view for explaining the effect of the heat transfer tube according to the first embodiment. [Figure 7] FIG. 7 is a schematic cross-sectional view of a heat exchanger according to the second embodiment. [Figure 8] FIG. 8 is a schematic cross-sectional view of a heat exchanger according to the third embodiment. [Figure 9] FIG. 9 is a schematic cross-sectional view of a heat exchanger according to the fourth embodiment. [Figure 10] FIG. 10 is a schematic cross-sectional view of a heat exchanger according to a fifth embodiment. [Figure 11] FIG. 11 is a schematic cross-sectional view of a heat transfer tube according to the sixth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Several embodiments will be described with reference to the drawings. In each embodiment, an air conditioner capable of cooling and heating operations is disclosed as an example of a refrigeration cycle apparatus equipped with a heat exchanger. However, the configuration disclosed in each embodiment can also be applied to refrigeration cycle apparatuses other than air conditioners. Furthermore, the heat exchanger disclosed in each embodiment can also be used in apparatuses other than refrigeration cycle apparatuses.

[0011] [First embodiment] 1 is a diagram showing a schematic configuration of a refrigeration cycle apparatus 1 according to a first embodiment. The refrigeration cycle apparatus 1 includes a compressor 2, a four-way valve 3, an outdoor heat exchanger 4, an expansion valve 5, an indoor heat exchanger 6, and refrigerant piping 7 connecting these elements. The refrigeration cycle apparatus 1 further includes an outdoor fan 8 that blows air to the outdoor heat exchanger 4, and an indoor fan 9 that blows air to the indoor heat exchanger 6.

[0012] The compressor 2 includes a compressor body 2a and an accumulator 2b. The accumulator 2b separates the refrigerant supplied via the refrigerant pipe 7 into gas and liquid, and supplies the gas refrigerant to the compressor body 2a. The compressor body 2a compresses the gas refrigerant supplied from the accumulator 2b to generate high-temperature, high-pressure gas refrigerant.

[0013] In such a refrigeration cycle device 1, it is possible to switch between cooling operation, heating operation, etc. by changing the flow of the refrigerant with the four-way valve 3. In the example of Fig. 1, the solid arrows indicate the flow of the refrigerant in cooling operation, and the dashed arrows indicate the flow of the refrigerant in heating operation.

[0014] For example, in cooling operation, the refrigerant flows in the order of the compressor 2, four-way valve 3, outdoor heat exchanger 4, expansion valve 5, and indoor heat exchanger 6. At this time, the outdoor heat exchanger 4 functions as a condenser, and the indoor heat exchanger 6 functions as an evaporator, thereby cooling the room.

[0015] On the other hand, in heating operation, the flow path of the four-way valve 3 switches as shown by the dashed line, and the refrigerant flows in the order of the compressor 2, four-way valve 3, indoor heat exchanger 6, expansion valve 5, and outdoor heat exchanger 4. At this time, the indoor heat exchanger 6 functions as a condenser, and the outdoor heat exchanger 4 functions as an evaporator, heating the room.

[0016] 2 is a schematic plan view of a heat exchanger 100 according to this embodiment. The heat exchanger 100 can be used as the outdoor heat exchanger 4 or the indoor heat exchanger 6 shown in FIG.

[0017] The heat exchanger 100 includes a first header 10 and a second header 20. The first header 10 and the second header 20 are both long tubes, and are arranged in parallel with each other with a gap therebetween.

[0018] Both ends of the first header 10 are closed by end caps 11, 12. Furthermore, the first header 10 has a first joint 13 for connection to the refrigerant pipe 7 of the refrigeration cycle device 1.

[0019] Similarly, both ends of the second header 20 are closed by end caps 21 and 22. Furthermore, the second header 20 has a second joint 23 for connection to the refrigerant pipe 7.

[0020] The heat exchanger 100 further includes a plurality of heat transfer tubes 30 and a plurality of fins (plate fins) 40. The plurality of heat transfer tubes 30 are arranged in parallel to one another at intervals in a first arrangement direction D1. The plurality of fins 40 are arranged in parallel to one another at intervals in a second arrangement direction D2.

[0021] 2, the arrangement pitch of the heat transfer tubes 30 in the first arrangement direction D1 is larger than the arrangement pitch of the fins 40 in the second arrangement direction D2. As one example, the interval (arrangement pitch) between adjacent fins 40 is about 1.5 mm.

[0022] One end of each heat transfer tube 30 in the second arrangement direction D2 is connected to the first header 10. The other end of each heat transfer tube 30 in the second arrangement direction D2 is connected to the second header 20. For example, when a refrigerant is supplied to the heat exchanger 100 through the first joint 13, the refrigerant is divided from the first header 10 to each heat transfer tube 30, merges in the second header 20, and is discharged from the heat exchanger 100 through the second joint 23. When a refrigerant is supplied to the heat exchanger 100 through the second joint 23, the refrigerant is divided from the second header 20 to each heat transfer tube 30, merges in the first header 10, and is discharged from the heat exchanger 100 through the first joint 13.

[0023] The above-mentioned outdoor heat exchanger 4 and indoor heat exchanger 6 may be configured by a plurality of heat exchangers 100 whose flow paths are connected to each other. In this case, either one of the first joint 13 and the second joint 23 may be used to connect the flow paths of the heat exchangers 100 to each other.

[0024] The first header 10, the second header 20, the heat transfer tubes 30, and the fins 40 are made of a metal material. For example, aluminum or an aluminum alloy can be used as the metal material. The first header 10, the second header 20, the heat transfer tubes 30, and the fins 40 are joined together by brazing, for example.

[0025] Fig. 3 is a schematic cross-sectional view of the heat exchanger 100 taken along line III-III in Fig. 2. Specifically, Fig. 3 shows a region including four heat transfer tubes 30 in the cross section of the heat exchanger 100 taken along line III-III in Fig. 2, and the lowermost heat transfer tube 30 in the drawing is indicated by a dashed line.

[0026] As shown in Fig. 3, a width direction WD of the heat transfer tube 30 and a thickness direction TD of the heat transfer tube 30 are defined. The heat transfer tube 30 is elongated in the second arrangement direction D2 shown in Fig. 2, and has a flat shape in which the thickness in the thickness direction TD is sufficiently smaller than the width in the width direction WD.

[0027] In this embodiment, the thickness direction TD coincides with the first arrangement direction D1. In addition, when the heat exchanger 100 is assembled to an outdoor unit as the outdoor heat exchanger 4, or when the heat exchanger 100 is assembled to an indoor unit as the indoor heat exchanger 6, the first arrangement direction D1 is parallel to the gravity direction GD.

[0028] The heat exchanger 100 is exposed to an airflow in the airflow direction SD. This airflow is generated by an outdoor fan 8 when the heat exchanger 100 is used as the outdoor heat exchanger 4, and is generated by an indoor fan 9 when the heat exchanger 100 is used as the indoor heat exchanger 6.

[0029] In this embodiment, the airflow direction SD and the width direction WD coincide with each other. In Fig. 3, the upstream side (primary side) of the heat exchanger 100 in the airflow direction SD is marked with USM, and the downstream side (secondary side) is marked with DSM.

[0030] The heat transfer tube 30 has a first end portion 31 and a second end portion 32 in the width direction WD. The first end portion 31 is a portion of the heat transfer tube 30 located at the most downstream DSM. The second end portion 32 is a portion of the heat transfer tube 30 located at the most upstream USM.

[0031] The heat transfer tube 30 has a plurality of refrigerant flow paths 33 that communicate with the flow paths in the first header 10 and the flow paths in the second header 20 shown in Fig. 2. These refrigerant flow paths 33 are aligned in the width direction WD between the first end portion 31 and the second end portion 32.

[0032] The fin 40 has a plurality of fin pieces 41 arranged between adjacent heat transfer tubes 30 in the first arrangement direction D1, and connection portions 42 (communication portions) connecting these fin pieces 41. In this embodiment, the connection portions 42 are located on the downstream DSM of each heat transfer tube 30. That is, the connection portions 42 are connected to the ends of the downstream DSM of each fin piece 41. The connection portions 42 are formed to communicate between both ends of the fin 40 in the first arrangement direction D1. In this embodiment, each fin piece 41 and the connection portions 42 communicating in the first arrangement direction D1 are formed integrally.

[0033] The fin pieces 41 arranged between adjacent heat transfer tubes 30 are in contact with both of these heat transfer tubes 30. A slit 43 is formed between adjacent fin pieces. The slit 43 opens at the end edge of the upstream USM of the fin 40. The heat transfer tube 30 is inserted into the slit 43.

[0034] The slit 43 has a widened portion 43a located in the upstream USM. The width of the widened portion 43a in the first array direction D1 decreases as it approaches the downstream DSM. By providing the widened portion 43a, it becomes possible to smoothly insert the heat transfer tube 30 into the slit 43 during the manufacture of the heat exchanger 100. A portion 43b near the end in the downstream DSM of the slit 43 has a shape that fits with a portion (the first curved surface 36, to be described later) near the first end 31 of the heat transfer tube 30.

[0035] FIG. 4 is an enlarged cross-sectional view of the heat transfer tube 30 shown in FIG. 3. A plurality of partition walls 33a are provided inside the heat transfer tube 30. By the partition walls 33a, the internal space of the heat transfer tube 30 is partitioned into a plurality of refrigerant flow paths 33.

[0036] The heat transfer tube 30 has an upper surface 34 and a lower surface 35. The upper surface 34 and the lower surface 35 are planes parallel to each other. Also, the upper surface 34 and the lower surface 35 are parallel to the width direction WD and perpendicular to the thickness direction TD.

[0037] The upper surface 34 has a width Wa in the width direction WD. The lower surface 35 has a width Wb in the width direction WD. In the present embodiment, the width Wb is larger than the width Wa (Wa < Wb). The upper surface 34 entirely overlaps the lower surface 35 in the thickness direction TD.

[0038] The heat transfer tube 30 further has a first curved surface 36 and a second curved surface 37 that connect the upper surface 34 and the lower surface 35. The first curved surface 36 can also be said to be the side surface of the downstream DSM of the heat transfer tube 30. The second curved surface 37 can also be said to be the side surface of the upstream USM of the heat transfer tube 30.

[0039] The first curved surface 36 is located between the upper surface 34 and the first end 31 in the width direction WD. The second curved surface 37 is located between the upper surface 34 and the lower surface 35 and the second end 32 in the width direction WD.

[0040] The first curved surface 36 has a width W1 (first width) in the width direction WD. The second curved surface 37 has a width W2 (second width) in the width direction WD. In this embodiment, the width W1 is greater than the width W2 (W1>W2). As an example, the width W1 is 1.5 times or more, preferably 2 times or more, of the width W2.

[0041] The first curved surface 36 entirely overlaps with the lower surface 35 in the thickness direction TD. On the other hand, the second curved surface 37 does not overlap with either the upper surface 34 or the lower surface 35 in the thickness direction TD. In the example of FIG. 4, no partition wall 33a is disposed between the first curved surface 36 and the lower surface 35. As another example, the partition wall 33a may be disposed between the first curved surface 36 and the lower surface 35.

[0042] The first curved surface 36 has a shape in which the distance from the lower surface 35 in the thickness direction TD decreases toward the first end portion 31. In this embodiment, the first curved surface 36 is composed of a plurality of portions having different curvatures. In the example of Fig. 4, the first curved surface 36 includes a first portion 36a having a radius of curvature R1a, a second portion 36b having a radius of curvature R1b, and a third portion 36c having a radius of curvature R1c.

[0043] The first portion 36a connects the upper surface 34 and the second portion 36b. The second portion 36b connects the first portion 36a and the third portion 36c. The third portion 36c connects the second portion 36b and the lower surface 35. The point of the third portion 36c that protrudes most toward the downstream DSM corresponds to the first end 31 of the heat transfer tube 30. That is, the first curved surface 36 includes the first end 31.

[0044] The center of curvature O1a of the first portion 36a is located below the first portion 36a (on the side of the lower surface 35). The center of curvature O1b of the second portion 36b is located above the second portion 36b. That is, the first portion 36a is convex toward the outside of the heat transfer tube 30. Also, the second portion 36b is concave toward the inside of the heat transfer tube 30. The line segment connecting the centers of curvature O1a and O1b intersects the first curved surface 36. The region of the first curved surface 36 composed of the first portion 36a and the second portion 36b is bent so that the cross-sectional shape is S-shaped. The radii of curvature R1a and R1b are, for example, the same, but they may be different from each other.

[0045] It is preferable that the radius of curvature R1c of the third portion 36c is sufficiently smaller than the radii of curvature R1a and R1b. In the example of FIG. 4, in the vicinity of the third portion 36c, the inner surfaces 38 of the heat transfer tube 30 are in contact with each other. Thereby, the radius of curvature R1c of the third portion 36c can be minimized.

[0046] In the example of FIG. 4, the second curved surface 37 is semi-circular with a constant curvature. The radius of curvature R2 of the second curved surface 37 is, for example, equivalent to the radius of curvature R1a. That is, the radius of curvature R1c of the third portion 36c is sufficiently smaller than the radius of curvature R2 (R1c < R2). Among the second curved surface 37, the point that most protrudes toward the upstream side USM corresponds to the second end portion 32. That is, the second curved surface 37 includes the second end portion 32.

[0047] Explaining the heat transfer tube 30 having the upper surface 34, the lower surface 35, the first curved surface 36, and the second curved surface 37 as described above from another perspective, the heat transfer tube 30 has a flat portion 30A having a certain thickness T, a first convex portion 30B protruding from the flat portion 30A toward the downstream side DSM, and a second convex portion 30C protruding from the flat portion 30A toward the upstream side USM.

[0048] The flat portion 30A is a portion whose outer surface is composed of the upper surface 34 and a portion of the lower surface 35, and has the same width Wa as the upper surface 34. The first convex portion 30B is a portion whose outer surface is composed of the first curved surface 36 and a portion of the lower surface 35, and has the same width W1 as the first curved surface 36. The second convex portion 30C is a portion whose outer surface is composed of the second curved surface 37, and has the same width W2 as the second curved surface 37.

[0049] The thickness of the first protrusion 30B decreases toward the first end 31. The thickness of the second protrusion 30C decreases toward the second end 32. The first protrusion 30B has a more pointed shape than the second protrusion 30C.

[0050] A first end 31, which is a tip of the first protrusion 30B, is located closer to the lower surface 35 than a center C in the thickness direction TD of the heat transfer tube 30. On the other hand, a second end 32, which is a tip of the second protrusion 30C, is located at the same position as the center C.

[0051] Next, an example of the effect achieved by this embodiment will be described. Fig. 5 is a schematic cross-sectional view of a heat transfer tube 30X according to a comparative example to this embodiment. Fig. 6 is a schematic cross-sectional view for explaining the effect of the heat transfer tube 30 according to this embodiment.

[0052] The heat transfer tube 30X shown in Fig. 5 has a first end 31X of the downstream DSM, a second end 32X of the upstream USM, an upper surface 34X, a lower surface 35X, a first curved surface 36X including the first end 31X, and a second curved surface 37X including the second end 32X. The shape of the second curved surface 37X is similar to the shape of the second curved surface 37 of the heat transfer tube 30 shown in Fig. 4. The first curved surface 37X also has a similar shape to the second curved surface 37X.

[0053] When a heat exchanger including this heat transfer tube 30X functions as an evaporator, liquid droplets 200 generated by condensation or the like may adhere to an upper surface 34X of the heat transfer tube 30X. The liquid droplets 200 are carried downstream DSM by the airflow flowing in the air blowing direction SD.

[0054] When the first curved surface 36X has the shape shown in the figure, the flow speed of the airflow decreases around the first end 31X. In addition, the liquid droplets 200 flow downward along the first curved surface 36X and are difficult to separate from the first end 31X. Therefore, the liquid droplets 200 remain on the surface of the heat transfer tube 30X for a long time, which causes frost formation. When frost forms, the heat exchange efficiency may decrease.

[0055] 6 according to this embodiment has a first curved surface 36 located above the lower surface 35 in the thickness direction TD in the vicinity of the first end 31. Furthermore, the distance between the first curved surface 36 and the lower surface 35 decreases as it approaches the first end 31. With this shape, the flat lower surface 35 extends up to the vicinity of the first end 31, and further, the first end 31 is pointed, so that the liquid droplets 200 that have flowed up to the first end 31 do not flow around below the heat transfer tube 30 and are easily blown away by the air current.

[0056] 4, the first curved surface 36 has a first portion 36a and a second portion 36b. The droplets 200 first flow smoothly downward by the first portion 36a, and then flow along the airflow direction SD by the second portion 36b toward the first end 31. If the droplets 200 flow along the airflow direction SD near the first end 31, the droplets 200 are likely to peel off from the surface of the heat transfer tube 30 at the pointed first end 31.

[0057] In this embodiment, the fin 40 has a connection portion 42 that connects each fin piece 41. Liquid droplets adhering to the fin 40 flow downward along the connection portion 42. In particular, in this embodiment, the connection portion 42 is provided on the first end portion 31 side (downstream DSM). In this case, liquid droplets adhering to the surface of the heat transfer tube 30 near the first end portion 31 tend to flow along the connection portion 42.

[0058] In this way, the shape of the heat transfer tube 30 according to this embodiment can improve the drainage of droplets adhering to the upper surface 34. This can suppress a decrease in heat exchange efficiency and improve the performance of the heat exchanger 100. In addition, the performance of the refrigeration cycle apparatus 1 including the heat exchanger 100 as at least one of the outdoor heat exchanger 4 and the indoor heat exchanger 6 can also be improved.

[0059] Other embodiments that can be applied to the heat exchanger 100 are disclosed below. Configurations not specifically mentioned in each embodiment are the same as those in the first embodiment. Furthermore, the configurations disclosed in each embodiment can be appropriately combined. [Second embodiment] 7 is a schematic cross-sectional view of a heat exchanger 100 according to a second embodiment. In this embodiment, the heat exchanger 100 is inclined with respect to the airflow direction SD so that the airflow hits the lower surface 35 of the heat transfer tube 30.

[0060] As a result, the width direction WD and the airflow direction SD are non-parallel to each other. The first arrangement direction D1 and the gravity direction GD, and further the thickness direction TD and the gravity direction GD are also non-parallel to each other. The first end 31 is located lower than the second end 32 in the gravity direction GD.

[0061] Even when the heat exchanger 100 is tilted with respect to the air blowing direction SD in this manner, if the heat transfer tube 30 has the shape shown in Figure 4, liquid droplets adhering to the surface of the heat transfer tube 30 can be drained effectively.

[0062] [Third embodiment] 8 is a schematic cross-sectional view of a heat exchanger 100 according to a third embodiment. In this embodiment, the heat transfer tube 30 is inclined with respect to the airflow direction SD so that the airflow hits the lower surface 35 of the heat transfer tube 30. As a result, the first end 31 is located lower in the gravity direction GD than the second end 32, similar to the second embodiment.

[0063] When the heat exchanger 100 is inclined with respect to the airflow direction SD in this manner, liquid droplets adhering to the heat transfer tube 30 tend to flow toward the first end 31. This allows liquid droplets adhering to the surface of the heat transfer tube 30 to be drained more efficiently.

[0064] [Fourth embodiment] 9 is a schematic cross-sectional view of a heat exchanger 100 according to a fourth embodiment. In this embodiment, the connection parts 42 of the fins 40 are provided on the upstream USM of each heat transfer tube 30. That is, the connection parts 42 are connected to the ends of the upstream USM of each fin piece 41.

[0065] The slits 43 open at the end edge of the downstream DSM of the fin 40. In the example of Fig. 9, the first end 31 of each heat transfer tube 30 protrudes further toward the downstream DSM than each fin piece 41, but this is not limited to this example.

[0066] Even when the connection portion 42 is provided on the upstream USM of each heat transfer tube 30 as in this embodiment, if the heat transfer tube 30 has the shape shown in Fig. 4, liquid droplets adhering to the surface of the heat transfer tube 30 can be drained well. Furthermore, liquid droplets adhering to the fins 40 flow downward along the connection portion 42, improving the drainage performance of the heat exchanger 100.

[0067] [Fifth embodiment] 10 is a schematic cross-sectional view of a heat exchanger 100 according to a fifth embodiment. In this embodiment, the fin 40 has a first connection portion 42a and a second connection portion 42b.

[0068] The first connection portion 42a is provided on the downstream DSM of each heat transfer tube 30. That is, the first connection portion 42a is connected to an end portion of the downstream DSM of each fin piece 41. The first connection portion 42a is formed across both ends of the fin 40 in the first arrangement direction D1.

[0069] The second connection portion 42b is provided on the upstream USM of each heat transfer tube 30. That is, the second connection portion 42b is connected to an end portion of the upstream USM of each fin piece 41. The second connection portion 42b is formed across both ends of the fin 40 in the first arrangement direction D1.

[0070] 10, the width of the first connection portion 42a is greater than the width of the second connection portion 42b. The slit 43 has the same shape as the outer shape of the heat transfer tube 30. The heat transfer tube 30 is fitted into the slit 43.

[0071] Even when the first connecting portion 42a and the second connecting portion 42b are provided as in this embodiment, so long as the heat transfer tubes 30 have the shape shown in Fig. 4, liquid droplets adhering to the surfaces of the heat transfer tubes 30 can be drained well. Furthermore, in the downstream DSM of each heat transfer tube 30, liquid droplets flow downward along the first connecting portion 42a, and in the upstream USM of each heat transfer tube 30, liquid droplets flow downward along the second connecting portion 42b, improving the drainage performance of the heat exchanger 100.

[0072] When air is blown, the liquid droplets adhering to the heat transfer tube 30 flow toward the downstream DSM. Therefore, as in the example of Fig. 10, the liquid droplets run down the first connecting portion 42a and are efficiently drained.

[0073] Incidentally, when the first connecting portion 42a and the second connecting portion 42b are provided on the fin 40, the fin 40 and the heat exchanger 100 may become large in size. In this regard, since the width of the second connecting portion 42b is small in the example of Fig. 10, the fin 40 and the heat exchanger 100 can be prevented from becoming large in size.

[0074] [Sixth embodiment] 11 is a schematic cross-sectional view of a heat transfer tube 30 according to a sixth embodiment. This heat transfer tube 30 differs from the example shown in FIG.

[0075] 11, the first curved surface 36 is curved at a constant curvature between the upper surface 34 and the first end portion 31. The first curved surface 36 is located above the lower surface 35 in the thickness direction TD, similar to the example of FIG. 4. The width W1 of the first curved surface 36 (first convex portion 30B) is greater than the width W2 of the second curved surface 37 (second convex portion 30C).

[0076] Even when the heat transfer tube 30 has a shape as in this embodiment, the drainage of droplets adhering to the upper surface 34 can be improved, similarly to the first embodiment.

[0077] The heat transfer tube 30 according to this embodiment can be applied to any of the heat exchangers 100 according to the above-mentioned embodiments. The shape of the heat transfer tube 30 is not limited to those shown in Fig. 4 and Fig. 11. For example, the shape of the first curved surface 36 (first convex portion 30B) can be modified into various other modes.

[0078] 4 and 11, a curved surface similar to the first curved surface 36 may be provided between the lower surface 35 and the first end 31. In addition, a curved surface similar to the first curved surface 36 may be provided between the upper surface 34 and the second end 32, or between the lower surface 35 and the second end 32.

[0079] In each embodiment, the heat exchanger 100 is disclosed that includes the plate-shaped fins 40. The heat transfer tube 30 in each embodiment can also be applied to other types of heat exchangers, such as a heat exchanger that includes wave-shaped corrugated fins.

[0080] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope and spirit of the invention, and are included in the scope of the invention and its equivalents described in the claims. [Explanation of symbols]

[0081] 1...refrigeration cycle device, 30...heat transfer tube, 31...first end, 32...second end, 33...refrigerant flow path, 33a...partition wall, 34...upper surface, 35...lower surface, 36...first curved surface, 37...second curved surface, 38...inner surface, 40...fin, 100...heat exchanger, WD...width direction, TD...thickness direction, GD...gravity direction, SD...air blowing direction.

Claims

1. a flat heat transfer tube having a first end and a second end in a width direction, and a plurality of refrigerant flow paths arranged in the width direction between the first end and the second end; A fin in contact with the heat transfer tube; Equipped with The heat transfer tube is An upper surface parallel to the width direction; A lower surface parallel to the upper surface; a first curved surface located between the upper surface and the first end in the width direction and above the lower surface in a thickness direction perpendicular to the upper surface and the lower surface; Including, The first curved surface is a first portion of the heat transfer tube that is convex toward an outside of the heat transfer tube; a second portion that is located between the first portion and the first end in the width direction and has a concave shape toward an inside of the heat transfer tube; a third portion connecting the second portion and the lower surface; Including, a distance between the first curved surface and the lower surface decreases toward the first end; The radius of curvature of the third portion is smaller than the radius of curvature of each of the first portion and the second portion. heat exchanger.

2. the heat transfer tube further has a second curved surface including the second end and connecting the upper surface and the lower surface; The first curved surface has a first width in the width direction, The second curved surface has a second width in the width direction, The first width is greater than the second width.

2. The heat exchanger of claim 1.

3. The first end is located lower than the second end in a direction of gravity.

3. A heat exchanger according to claim 1 or 2.

4. A plurality of the heat transfer tubes are arranged in parallel at intervals, The fin is A plurality of fin pieces each positioned between adjacent heat transfer tubes; a communication portion that communicates with the heat transfer tubes in an arrangement direction at an end portion of the plurality of fins in the width direction; It has A heat exchanger according to any one of claims 1 to 3.

5. A heat exchanger according to any one of claims 1 to 4; a fan for generating an airflow through the heat exchanger; Equipped with The first end is located downstream of the airflow relative to the second end. Refrigeration cycle equipment.

Images