JP7608230B2 - Heat exchanger and refrigeration cycle device - Google Patents

Description

Embodiments of the present invention relate to a heat exchanger and a refrigeration cycle device.

Conventionally, a heat exchanger is known that includes multiple flat heat transfer tubes with a refrigerant flow path inside and multiple fins that contact the heat transfer tubes. This type of heat exchanger is used in refrigeration cycle devices such as air conditioners.

When a heat exchanger functions as an evaporator, liquid droplets (water droplets) formed by condensation, etc. 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.

JP 2018-523175 A

The problem that the present invention aims to solve is to provide a heat exchanger that can effectively drain droplets adhering to a heat transfer tube, and a refrigeration cycle device equipped with the heat exchanger.

The heat exchanger according to 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 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 that is convex toward the outside of the heat transfer tube, a second portion that is concave toward the inside of the heat transfer tube and is located between the first portion and the first end in the width direction, and a third portion that connects the second portion and the lower surface . The distance between the first curved surface and the lower surface decreases as the first end is approached. 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.

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 the 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 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 as it approaches 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 as it approaches the second end. The first width is greater than the second width.

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.

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

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 device equipped with a heat exchanger. However, the configuration disclosed in each embodiment can also be applied to refrigeration cycle devices other than air conditioners. In addition, the heat exchanger disclosed in each embodiment can also be used in devices other than refrigeration cycle devices.

[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.

The compressor 2 includes a compressor body 2a and an accumulator 2b. The accumulator 2b separates the refrigerant supplied through 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.

In such a refrigeration cycle device 1, the four-way valve 3 can be used to change the flow of refrigerant, thereby switching between cooling operation, heating operation, etc. In the example of Figure 1, the solid arrows indicate the flow of refrigerant in cooling operation, and the dashed arrows indicate the flow of refrigerant in heating operation.

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

On the other hand, during heating operation, the flow path of the four-way valve 3 switches as shown by the dashed lines, and the refrigerant flows through the compressor 2, four-way valve 3, indoor heat exchanger 6, expansion valve 5, and outdoor heat exchanger 4 in that order. 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.

Figure 2 is a schematic plan view of the heat exchanger 100 according to this embodiment. This heat exchanger 100 can be used for the outdoor heat exchanger 4 and the indoor heat exchanger 6 shown in Figure 1.

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 that are arranged in parallel with a gap between them.

Both ends of the first header 10 are closed by end caps 11 and 12. Furthermore, the first header 10 has a first fitting 13 for connecting to the refrigerant piping 7 of the refrigeration cycle device 1.

Similarly, both ends of the second header 20 are closed by end caps 21 and 22. Furthermore, the second header 20 has a second fitting 23 for connecting to the refrigerant piping 7.

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

In the example of FIG. 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 an example, the distance (arrangement pitch) between adjacent fins 40 is about 1.5 mm.

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 diverted 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 diverted 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.

The above-mentioned outdoor heat exchanger 4 and indoor heat exchanger 6 may be configured by multiple heat exchangers 100 whose flow paths are connected to each other. In this case, either the first joint 13 or the second joint 23 may be used to connect the flow paths between the heat exchangers 100.

The first header 10, the second header 20, the heat transfer tubes 30, and the fins 40 are formed 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, for example, brazing.

Figure 3 is a schematic cross-sectional view of the heat exchanger 100 taken along line III-III in Figure 2. Specifically, Figure 3 shows an area including four heat transfer tubes 30 in the cross section of the heat exchanger 100 taken along line III-III in Figure 2, with the lowermost heat transfer tube 30 shown in dashed lines.

As shown in FIG. 3, the width direction WD of the heat transfer tube 30 and the 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.

In this embodiment, the thickness direction TD coincides with the first arrangement direction D1. Furthermore, 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.

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

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 the symbol USM, and the downstream side (secondary side) is marked with the symbol DSM.

The heat transfer tube 30 has a first end 31 and a second end 32 in the width direction WD. The first end 31 is the part of the heat transfer tube 30 located on the most downstream side DSM. The second end 32 is the part of the heat transfer tube 30 located on the most upstream side USM.

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 31 and the second end 32.

The fin 40 has a plurality of fin pieces 41 arranged between adjacent heat transfer tubes 30 in the first arrangement direction D1, and a connection portion 42 (communication portion) that connects these fin pieces 41. In this embodiment, the connection portion 42 is located on the downstream DSM of each heat transfer tube 30. In other words, the connection portion 42 is connected to the end of the downstream DSM of each fin piece 41. The connection portion 42 is formed so as 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 portion 42 that communicates in the first arrangement direction D1 are formed integrally.

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.

The slit 43 has a widened portion 43a located on the upstream USM. The width of the widened portion 43a in the first arrangement 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. The portion 43b near the end of the slit 43 on the downstream DSM has a shape that fits into the portion near the first end 31 of the heat transfer tube 30 (the first curved surface 36 described later).

Figure 4 is an enlarged cross-sectional view of the heat transfer tube 30 shown in Figure 3. A plurality of partition walls 33a are provided inside the heat transfer tube 30. The partition walls 33a divide the internal space of the heat transfer tube 30 into a plurality of refrigerant flow paths 33.

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. The upper surface 34 and the lower surface 35 are also parallel to the width direction WD and perpendicular to the thickness direction TD.

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 this embodiment, the width Wb is greater than the width Wa (Wa<Wb). The upper surface 34 entirely overlaps the lower surface 35 in the thickness direction TD.

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.

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.

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.

The first curved surface 36 overlaps the lower surface 35 entirely in the thickness direction TD. On the other hand, the second curved surface 37 does not overlap 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, a partition wall 33a may be disposed between the first curved surface 36 and the lower surface 35.

The first curved surface 36 has a shape in which the distance between the first curved surface 36 and the lower surface 35 in the thickness direction TD decreases as the first end 31 approaches. In this embodiment, the first curved surface 36 is composed of multiple portions with 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.

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. In other words, the first curved surface 36 includes the first end 31.

The center of curvature O1a of the first portion 36a is located lower than the first portion 36a (toward the lower surface 35). The center of curvature O1b of the second portion 36b is located higher than the second portion 36b. That is, the first portion 36a is convex toward the outside of the heat transfer tube 30. 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 with the first curved surface 36. The region of the first curved surface 36 that is formed by the first portion 36a and the second portion 36b is curved so that the cross-sectional shape is S-shaped. The radii of curvature R1a and R1b are, for example, the same, but may be different from each other.

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, the inner surfaces 38 of the heat transfer tubes 30 are in contact with each other near the third portion 36c. This allows the radius of curvature R1c of the third portion 36c to be minimized.

In the example of FIG. 4, the second curved surface 37 is semicircular with a constant curvature. The radius of curvature R2 of the second curved surface 37 is, for example, equal 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). The point of the second curved surface 37 that protrudes most toward the upstream USM corresponds to the second end 32. That is, the second curved surface 37 includes the second end 32.

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

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.

The thickness of the first protrusion 30B decreases as it approaches the first end 31. The thickness of the second protrusion 30C decreases as it approaches the second end 32. The first protrusion 30B has a more pointed shape than the second protrusion 30C.

The first end 31, which is the tip of the first convex portion 30B, is located on the lower surface 35 side compared to the center C in the thickness direction TD of the heat transfer tube 30. On the other hand, the position of the second end 32, which is the tip of the second convex portion 30C, coincides with the center C.

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 of the present embodiment. Fig. 6 is a schematic cross-sectional view for explaining the effect of the heat transfer tube 30 according to the present embodiment.

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.

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

When the first curved surface 36X has the shape shown in the figure, the air flow speed 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. As a result, the liquid droplets 200 remain on the surface of the heat transfer tube 30X for a long period of time, which causes frost formation. When frost forms, the heat exchange efficiency may decrease.

On the other hand, the heat transfer tube 30 according to this embodiment shown in FIG. 6 has a first curved surface 36 located above the lower surface 35 in the thickness direction TD near 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, because the first end 31 is pointed, the droplets 200 that flow 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.

As explained with reference to FIG. 4, the first curved surface 36 has a first portion 36a and a second portion 36b. The droplets 200 first flow smoothly downward through the first portion 36a, and then flow along the airflow direction SD toward the first end 31 through the second portion 36b. 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.

In this embodiment, the fin 40 has a connection portion 42 that connects each fin piece 41. Liquid droplets that adhere 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 31 side (downstream DSM). In this case, liquid droplets that adhere to the surface of the heat transfer tube 30 near the first end 31 tend to flow along the connection portion 42.

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. It can also improve the performance of the refrigeration cycle device 1 that includes the heat exchanger 100 as at least one of the outdoor heat exchanger 4 and the indoor heat exchanger 6.

Other embodiments that can be applied to the heat exchanger 100 will be disclosed below. Configurations that are not specifically mentioned in each embodiment are similar to those in the first embodiment. In addition, 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.

As a result, the width direction WD and the airflow direction SD are non-parallel. Furthermore, 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. The first end 31 is located lower in the gravity direction GD than the second end 32.

Even if the heat exchanger 100 is tilted with respect to the airflow direction SD in this way, 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.

[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 than the second end 32 in the gravity direction GD, as in the second embodiment.

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

[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.

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

Even if a 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. In addition, liquid droplets adhering to the fins 40 flow downward along the connection portion 42, improving the drainage performance of the heat exchanger 100.

[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.

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 the end of the downstream DSM of each fin piece 41. The first connection portion 42a is formed between both ends of the fin 40 in the first arrangement direction D1.

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 the end of the upstream USM of each fin piece 41. The second connection portion 42b is formed between both ends of the fin 40 in the first arrangement direction D1.

In the example of FIG. 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.

Even when the first connection portion 42a and the second connection portion 42b are provided as in this embodiment, if the heat transfer tube 30 has the shape shown in FIG. 4, the liquid droplets adhering to the surface of the heat transfer tube 30 can be drained well. In addition, in the downstream DSM of each heat transfer tube 30, the liquid droplets flow downward along the first connection portion 42a, and in the upstream USM of each heat transfer tube 30, the liquid droplets flow downward along the second connection portion 42b, improving the drainage performance of the heat exchanger 100.

When air is blown, the liquid droplets adhering to the heat transfer tube 30 flow toward the downstream DSM. Therefore, as shown in the example of FIG. 10, the liquid droplets flow along the first connection portion 42a and are efficiently drained.

When the fin 40 is provided with the first connection portion 42a and the second connection portion 42b, the fin 40 and the heat exchanger 100 may become larger. In this regard, in the example of FIG. 10, the width of the second connection portion 42b is small, so that the fin 40 and the heat exchanger 100 can be prevented from becoming larger.

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

In other words, in the example of FIG. 11, the first curved surface 36 is curved at a constant curvature between the upper surface 34 and the first end portion 31. Note that the first curved surface 36 is located above the lower surface 35 in the thickness direction TD, as in the example of FIG. 4. Also, 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).

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

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 that 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 forms.

In the heat transfer tube 30 shown in Figures 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. Also, 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.

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

Although several 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 embodied in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention. These embodiments and their modifications are included in the scope and gist of the invention, and are included in the scope of the invention and its equivalents described in the claims.

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 (5)

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. 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. 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. 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. 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.

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