Heat exchanger and method for manufacturing the same

Abstract

A heat exchanger (1A) comprises: a first header including a first bent portion and a first straight portion extending from the first bent portion; a second header having a second bent portion which is bent in the same direction as the first bent portion and which opposes the first bent portion, and a second straight portion extending from the second bent portion; a plurality of first heat transfer tubes which are aligned along the first bent portion and which connect the first bent portion and the second bent portion; and a plurality of fins (40A) which are provided between each of the first heat transfer tubes that are adjacent to one another to transfer heat in the first heat transfer tubes. At least one of the plurality of fins (40A) has a low-strength part which has a lower rigidity than other parts thereof and which deforms more readily than the other parts when a distance between the adjacent first heat transfer tubes changes.

Description

[Technical Field]

[0001] FIELD OF THE DISCLOSURE The present disclosure relates to heat exchangers and methods for manufacturing heat exchangers. [Background technology]

[0002] Some heat exchangers have partially bent headers that distribute or aggregate refrigerant to heat transfer tubes for easier installation. These heat exchangers are manufactured by first attaching heat transfer tubes and fins to a linearly extending header, and then bending the header. Therefore, in this type of heat exchanger, the fins can become deformed during the process of bending the header. To prevent this fin deformation, heat exchangers with fins that are designed to prevent deformation have been developed.

[0003] For example, Patent Document 1 discloses a heat exchanger in which two types of fins with different depth widths are arranged alternately in the arrangement direction of the heat transfer tubes in multiple gaps formed between the heat transfer tubes arranged in the bent portion of the header.

[0004] Patent Document 1 claims that by using two types of fins with different widths in the depth direction, it is possible to prevent the fins from being significantly deformed or broken during the bending process when manufacturing a heat exchanger. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2015 / 027680 Summary of the Invention [Problem to be solved by the invention]

[0006] However, even if deformation of the fins can be avoided during the bending process, a compressive force is applied to the inner side of the bent portion of the header during the bending process, which may cause deformation of the heat transfer tubes at the bent portion of the header.

[0007] Furthermore, deformation of the heat transfer tube may cause the flow passages inside the heat transfer tube to become blocked or narrow, which may result in a decrease in the efficiency of heat exchange.

[0008] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a heat exchanger and a method for manufacturing a heat exchanger in which deformation of the heat transfer tubes at the bent portion of the header is suppressed and a decrease in heat exchange efficiency is suppressed. [Means for solving the problem]

[0009] In order to achieve the above object, a heat exchanger according to the present disclosure includes a first header having a first bent portion, a second header having a second bent portion bent in the same direction as the first bent portion and facing the first bent portion, a plurality of first heat transfer tubes arranged along the first bent portion and connecting the first bent portion and the second bent portion, a plurality of second heat transfer tubes arranged along the first straight portion and connecting the first straight portion and the second straight portion; Between adjacent first heat transfer tubes and between adjacent second heat transfer tubes Each is equipped with a first heat transfer tube and the second heat transfer tube, respectively and a plurality of fins for transferring heat from the first heat transfer tube to the second heat transfer tube. At least one of the plurality of fins has a low-strength portion that is less rigid than other portions of the fin and is more likely to deform than other portions when the distance between adjacent first heat transfer tubes changes. At least one of the plurality of second heat transfer tubes is bent in a convex shape toward the side where the first bent portion and the second bent portion are located. [Effects of the Invention]

[0010] According to the configuration of the present disclosure, at least one of the multiple fins has a low-strength portion that is less rigid than the other portions thereof and is more likely to deform than the other portions when the spacing between adjacent first heat transfer tubes changes. Therefore, when the spacing between the first heat transfer tubes changes during the bending process of forming the first bent portion and the second bent portion in the first header and the second header, the low-strength portion of the fin deforms before the other portions of the fin. As a result, deformation of the first heat transfer tube is suppressed. Furthermore, as a result of suppressing deformation of the first heat transfer tube, a decrease in the heat exchange efficiency of the heat exchanger is suppressed. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a heat exchanger according to a first embodiment of the present disclosure; [Figure 2] FIG. 2 is an enlarged perspective view of the area II shown in FIG. 1 when viewed from the rear side; [Figure 3] FIG. 1 is an enlarged perspective view of a fin attached to a heat transfer tube connected to a bent portion of a header included in a heat exchanger according to a first embodiment of the present disclosure. [Figure 4] FIG. 1 is a cross-sectional view of a fin positioned to overlap a bent portion of a heat exchanger according to a first embodiment of the present disclosure in a vertical direction; [Figure 5] Flowchart of a method for manufacturing a heat exchanger according to the first embodiment of the present disclosure [Figure 6] FIG. 10 is a front view of a plurality of heat transfer tubes sandwiching fins and unprocessed fins during an assembly process of a semi-finished heat exchanger included in a method for manufacturing a heat exchanger according to the first embodiment of the present disclosure. [Figure 7] FIG. 1 is a front view of a semi-finished heat exchanger fabricated in an assembly step of a semi-finished heat exchanger included in a manufacturing method for a heat exchanger according to a first embodiment of the present disclosure. [Figure 8] FIG. 10 is an enlarged rear view of a portion of the heat exchanger in a modified example of the heat exchanger according to the first embodiment of the present disclosure, in which a heat transfer tube is bent. [Figure 9] FIG. 10 is an enlarged perspective view of a portion of a heat transfer tube and fins included in a heat exchanger according to a second embodiment of the present disclosure. [Figure 10] FIG. 10 is an enlarged perspective view of a portion of a modified example of a heat exchanger according to the second embodiment of the present disclosure. [Figure 11] FIG. 10 is an enlarged perspective view of a portion of another modified example of the heat exchanger according to the second embodiment of the present disclosure. [Figure 12] FIG. 11 is an enlarged perspective view of a portion of a heat transfer tube and fins included in a heat exchanger according to a third embodiment of the present disclosure. [Figure 13] FIG. 11 is an enlarged perspective view of a portion of a modified example of a heat exchanger according to a third embodiment of the present disclosure. [Figure 14] FIG. 10 is an enlarged cross-sectional view of a portion of a fin included in a heat exchanger according to a fourth embodiment of the present disclosure. [Figure 15]FIG. 13 is an enlarged perspective view of a portion of a heat transfer tube and fins included in a heat exchanger according to a fifth embodiment of the present disclosure. [Figure 16] 1 is a development view of a modified example of the heat exchanger according to the first embodiment of the present disclosure. [Figure 17] 10 is a development view of another modified example of the heat exchanger according to the first embodiment of the present disclosure. [Figure 18] FIG. 10 is a cross-sectional view of yet another modified example of the fins included in the heat exchanger according to the first embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0012] Hereinafter, a heat exchanger and a manufacturing method for a heat exchanger according to an embodiment of the present disclosure will be described in detail with reference to the drawings. In the drawings, identical or equivalent parts are designated by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, the direction in which the tube axes of the heat transfer tubes included in the heat exchanger extend is the vertical direction, and the direction in which the heat transfer tubes are arranged is the horizontal direction. The vertical direction is the Z axis, the horizontal direction is the X axis, and the direction perpendicular to the Z axis and the X axis is the Y axis. This coordinate system will be referred to as appropriate in the following description.

[0013] (Embodiment 1) The heat exchanger according to the first embodiment is a heat exchanger in which the fins at the bent portion of the header have low strength portions to suppress deformation of the heat transfer tubes. The configuration of the heat exchanger will be described below using the case where this heat exchanger is used in the outdoor unit of an air conditioner as an example. First, the overall configuration of the heat exchanger will be described with reference to Figures 1 and 2.

[0014] Fig. 1 is a perspective view of a heat exchanger 1A according to a first embodiment. Fig. 2 is an enlarged perspective view of the region II shown in Fig. 1 when the region II is viewed from the rear side B. For ease of understanding, Fig. 1 shows only the heat transfer tubes 20 and fins 30 in a portion of the heat exchanger 1A, and omits the heat transfer tubes 20 and fins 30 in other portions. Fig. 2 also shows only three heat transfer tubes 20 adjacent to each other in the left-right direction and the two fins 30 therebetween.

[0015] As shown in FIG. 1, the heat exchanger 1A includes headers 11 and 12 for distributing and collecting the refrigerant, a plurality of heat transfer tubes 20 connected to the headers 11 and 12 and through which the refrigerant flows, and a plurality of fins 30 attached to the heat transfer tubes 20.

[0016] The headers 11 and 12 are formed in the shape of a rectangular tube. Although not shown, flow paths are formed inside the headers 11 and 12. The headers 11 and 12 also have cylindrical connection parts 13 and 14 shown in Fig. 1, and connection pipes of external equipment (not shown) that supply and discharge refrigerant are connected to these connection parts 13 and 14. When the external equipment is connected to the headers 11 and 12, the refrigerant flows through the internal flow paths.

[0017] 1, the headers 11 and 12 are arranged spaced apart from each other in the vertical direction with their pipe axes A1 and A2 oriented horizontally. A plurality of heat transfer pipes 20 are connected to the headers 11 and 12 to allow the refrigerant to circulate between them.

[0018] Each heat transfer tube 20 is formed in a tubular shape to allow a refrigerant to flow therethrough. The heat transfer tubes 20 extend in the vertical direction. Furthermore, the upper and lower ends of the heat transfer tubes 20 are inserted into insertion holes (not shown) in the cylindrical walls of the headers 11 and 12. In this way, the heat transfer tubes 20 are connected to the headers 11 and 12. As a result, the refrigerant flows through the heat transfer tubes 20 when it flows through the headers 11 and 12.

[0019] Each heat transfer tube 20 is made of a metal with high thermal conductivity, such as pure aluminum or an aluminum alloy, to facilitate the transfer of heat from the refrigerant flowing therethrough. Furthermore, each heat transfer tube 20 has a flattened cross section to facilitate the transfer of heat from the refrigerant. That is, the heat transfer tubes 20 are flattened tubes. As shown in FIG. 1 , the heat transfer tubes 20 are arranged at a constant pitch in the axial direction of the headers 11 and 12. This provides gaps between the heat transfer tubes 20. Fins 30 are provided in the gaps to release the heat transferred to the heat transfer tubes 20 into the surrounding air.

[0020] The fins 30 are formed of a metal with high thermal conductivity, for example, the same metal material as the heat transfer tubes 20, to facilitate heat transfer from the heat transfer tubes 20. Furthermore, the fins 30 are formed in a plate shape, as shown in FIG. 2, to facilitate heat release into the surrounding air. The plate of the fins 30 is folded into a corrugated shape. The fins 30 are sandwiched between adjacent heat transfer tubes 20 with the peaks and valleys of the corrugations facing the flat surfaces of the heat transfer tubes 20. The peaks and valleys of the corrugations of the fins 30 are joined to the heat transfer tubes 20, respectively. Thus, the fins 30 are attached to the heat transfer tubes 20. As a result, the fins 30 release the heat transferred from the heat transfer tubes 20 into the air from the surface of the corrugated plate.

[0021] 1, headers 11 and 12 are bent into an L-shape so as to be incorporated into the rectangular parallelepiped housing of the outdoor unit. More specifically, headers 11 and 12 are bent at right angles, resulting in L-shaped bent portions 15 and 16 and linear portions 17 and 18 that are connected to bent portions 15 and 16 and extend linearly.

[0022] The bent portions 15 and 16 are produced by assembling a semi-finished heat exchanger having linearly extending headers 11 and 12, and then bending the semi-finished heat exchanger. During the bending process, compressive force is applied to the inner side of the bend of the semi-finished heat exchanger. As a result, the fins 30 may be deformed into irregular shapes. This may result in variations in ventilation resistance among the fins 30, reducing the heat exchange efficiency of the heat exchanger 1A.

[0023] Furthermore, the compressive force generated during the bending process may deform the heat transfer tube 20, which may block or reduce the flow path inside the heat transfer tube 20. As a result, the heat exchange efficiency of the heat exchanger 1A may decrease.

[0024] Therefore, in the heat exchanger 1A, the fins 30 are deformed at specific locations during the bending process during manufacturing, thereby suppressing irregular deformation of the fins 30 and suppressing deformation of the heat transfer tubes 20 preferentially over deformation of the fins 30. Therefore, the fins 30 at the bending portions 15 and 16 are provided with low-strength portions at specific locations that are less rigid than other portions and are more susceptible to deformation when bent.

[0025] Next, the configuration of the fins 40A and the low strength portions will be described with reference to Figures 3 and 4. For ease of understanding, hereinafter, the fins 30 at the bent portions 15 and 16 will be referred to as fins 40A.

[0026] Fig. 3 is an enlarged perspective view of a fin 40A attached to a heat transfer tube 20 connected to the bent portions 15, 16 of the headers 11, 12. Fig. 4 is a cross-sectional view of the fin 40A positioned to overlap the bent portions 15, 16 of the heat exchanger 1A in the vertical direction. Fig. 3 is an enlarged perspective view of the region IV shown in Fig. 1 when viewed from the rear side B. For ease of understanding, the internal structure of the heat transfer tube 20 is omitted from Fig. 4.

[0027] 3, like the fin 30, the fin 40A has a corrugated plate shape bent in such a way that waves continue in the vertical direction. The peaks 401 of the corrugations contact the heat transfer tubes 20 on the +X side, and the valleys 402 of the waves contact the heat transfer tubes 20 on the -X side. Furthermore, the peaks 401 and valleys 402 are connected to each other by plate-like portions 41. In other words, the fin 40A has a plurality of plate-like portions 41 that cross the gaps between adjacent heat transfer tubes 20 from one side to the other.

[0028] Such fins 40A are attached to the heat transfer tubes 20 at the bent portions 15, 16 of the headers 11, 12. Each of the plate-like portions 41 of the fins 40A is provided with a low-strength portion.

[0029] Here, in this specification, the low-strength portion refers to a portion formed on the plate-shaped portion 41 of the fin 40A and having lower rigidity than other portions of the plate-shaped portion 41. In more detail, the low-strength portion refers to a portion that is more likely to deform than other portions of the plate-shaped portion 41 when the gap between adjacent heat transfer tubes 20 changes, for example, when the gap between the heat transfer tubes 20 on the inner side of the bend is narrowed by bending. Being more likely to deform than other portions means, for example, in the case of the heat exchanger 1A, that it is more likely to bend than other portions.

[0030] The detailed configuration of the low strength portion will be described. The low strength portion is formed by a fin bent portion 42 formed by bending the plate-shaped portion 41 into a shape that protrudes downward.

[0031] The fin bent portion 42 has a shape in which the plate-shaped portion 41 is bent in a V-shape at the center in the arrangement direction of the heat transfer tubes 20. That is, the fin bent portion 42 has a shape in which the plate-shaped portion 41 is bent in a V-shape at the center between adjacent heat transfer tubes 20. As a result, when the size of the gap between adjacent heat transfer tubes 20 changes due to the bending process during manufacturing, the fin bent portion 42 is more likely to deform and bend than other portions of the plate-shaped portion 41. When the size of the gap between the heat transfer tubes 20 changes, the fin bent portion 42 deforms into a shape in which the V-shape angle increases or decreases. In other words, the fin bent portion 42 expands and contracts while maintaining the folds during the bending process during manufacturing, similar to a bellows, thereby regularly deforming the fins 40A. As a result, the fin bent portion 42 prevents the fins 40A from being irregularly deformed during the bending process, which would result in a decrease in ventilation performance. The fin bent portions 42 also maintain the ventilation performance of the fins 40A to a certain extent. Furthermore, when a compressive force is applied due to bending of the headers 11 and 12, the fin bent portions 42 expand and contract like a bellows, thereby suppressing the concentration of the compressive force on the heat transfer tubes 20. As a result, the fin bent portions 42 suppress deformation of the heat transfer tubes 20.

[0032] Furthermore, the fin bent portions 42 have a V-shaped shape with the tip of the V protruding downward. As a result, when water droplets adhere to the fin 40A, the fin bent portions 42 collect the water droplets at the tip of the V and drain them. As a result, the fin bent portions 42 improve the drainage performance of the fin 40A.

[0033] Furthermore, the fin bent portion 42 is formed at the end portion facing the inside of the bend of the plate-like portion 41 in order to enable deformation according to the compressive force applied during the bending process during manufacturing.

[0034] More specifically, as shown in FIG. 4, the bent portion 16 of the header 12 is bent toward the back side B when viewed from the right. Therefore, the inner side of the bent portion 16 is the back side B. A large compressive force is likely to be applied to the back side B of the bent portion 16 during the bending process during manufacturing. Therefore, the fin bent portion 42 is formed in a portion of the plate-shaped portion 41 that includes the end face of the back side B, i.e., in the end face of the back side B and its vicinity. Here, the end face refers to the side surface when the plate surface of the plate-shaped portion 41 is facing up or down.

[0035] When the plate-shaped portion 41 is viewed perpendicularly to the plate surface, the fin bent portion 42 has an isosceles triangular shape with its base facing the end surface of the back surface side B of the plate-shaped portion 41. The fin bent portion 42 is formed by bending the plate-shaped portion 41 along mountain folds 421 and 422 that are the equal sides of the isosceles triangle. The fin bent portion 42 is also formed by bending the plate-shaped portion 41 along a valley fold 424 that is a perpendicular line drawn from the apex 423 of the isosceles triangle to the base. As a result, the area of ​​the bent portion of the plate-shaped portion 41 increases toward the back surface side B. The compressive force applied during the bending process during manufacturing is greater toward the back surface side than toward the neutral plane. The area of ​​the fin bent portion 42 increases toward the back surface side B, enabling deformation in response to compressive force. This makes it easier for the fin bent portions 42 to be deformed by the compressive force of the bending process than the heat transfer tube 20 , and as a result, the compressive force of the bending process is less likely to be applied to the heat transfer tube 20 .

[0036] Furthermore, by bending the plate-shaped portion 41 into the above-described shape, the fin bending portion 42 has a V-shaped bend that becomes larger toward the back side B. As a result, as shown in Fig. 3, the fin bending portion 42 forms a V-shaped groove on the upper surface side of the plate-shaped portion 41 that becomes deeper toward the back side B. In this way, when water droplets adhere to the fin 40A, the fin bending portion 42 effectively discharges the water droplets to the outside of the fin 40A.

[0037] It is desirable that the extension of the folds 424 of the fin bending portions 42 point toward the bending center C1 shown in Fig. 4. This is because such folds 424 allow the compressive force applied during the bending process during manufacturing to be applied evenly to each part of the fin bending portions 42, making it easier for the fin bending portions 42 to deform regularly. As a result, it is possible to prevent the compressive force from concentrating on some of the heat transfer tubes 20.

[0038] Furthermore, it is desirable that vertex 423, which is the joining point of folds 421 and 422, is on or near the neutral plane of plate-shaped portion 41. This is because, with this configuration, fin bending portion 42 can be effectively positioned at a location where compressive force is generated during bending during manufacturing.

[0039] Next, a method for manufacturing the heat exchanger 1A having such fins 40A will be described with reference to FIGS.

[0040] Fig. 5 is a flowchart of a method for manufacturing a heat exchanger 1A. Fig. 6 is a front view of a plurality of heat transfer tubes 20 sandwiching fins 30 and unprocessed fins 50 in a step of assembling a semi-finished heat exchanger 2 included in the method for manufacturing a heat exchanger 1A. Fig. 7 is a front view of a semi-finished heat exchanger 2 fabricated in a step of assembling a semi-finished heat exchanger 2 included in the method for manufacturing a heat exchanger 1A.

[0041] First, as shown in Fig. 5, a straight tubular header, heat transfer tubes 20, and fins 30 are fabricated (step S1). Here, a straight tubular header refers to a header with a linear tube axis that does not have bent portions 15, 16, and refers to a header before being processed into headers 11, 12. For example, two straight tubular headers are fabricated by pressing a metal plate made of the above-mentioned material.

[0042] Furthermore, for example, the fin 30 having the above-described shape is produced by pressing a metal plate made of the above-described material. To obtain a semi-finished product to be processed into the fin 40A, a fin having a longer length from the corrugated peaks 401 to the valleys than the fin 30 is produced. Hereinafter, this fin will be referred to as the unprocessed fin.

[0043] Furthermore, the metal material described above is extruded to produce the heat transfer tube 20 having the shape described above.

[0044] Next, the heat exchanger 2 in a semi-finished product state is assembled using the manufactured straight tubular headers, heat transfer tubes 20, fins 30 and unprocessed fins (step S2).

[0045] In this assembly process, first, a plurality of heat transfer tubes 20 are arranged with their tube axes facing the same direction and their flat surfaces facing each other. Then, fins 30 or pre-machined fins are sandwiched between the heat transfer tubes 20 with the corrugated peaks 401 and valleys 402 facing the flat surfaces of the heat transfer tubes 20. At this time, as shown in Fig. 6, pre-machined fins 50 are sandwiched between the heat transfer tubes 20 attached to portions P1 of the straight tubular headers 21, 22 that will become the bent portions 15, 16 in step S3, which will be described later. Fins 30 are sandwiched between the heat transfer tubes 20 attached to the other portions P2, P3 of the straight tubular headers 21, 22.

[0046] Next, the core is assembled by inserting one end and the other end of the heat transfer tube 20 in this state into insertion holes (not shown) of the straight tubular headers 21 and 22. Subsequently, the various parts of the assembled core are brazed together to produce the semi-finished heat exchanger 2 shown in FIG.

[0047] Next, as shown in FIG. 5, fin bent portions 42 are formed (step S3). More specifically, the unprocessed fin 50 of the semi-finished heat exchanger 2 has a plurality of plate-like portions 41 connecting the corrugated peaks 401 and valleys 402, similar to the case shown in FIG. 3. These plate-like portions 41 cross the gaps between the heat transfer tubes 20. Although not shown, after the semi-finished heat exchanger 2 is fabricated, the comb teeth of a comb-like tool are inserted into the gaps between the heat transfer tubes 20 from the rear side B and pressed against each of the plate-like portions 41, thereby bending each of the plate-like portions 41 into the V-shape described above. This forms fin bent portions 42 on the rear surface of the plate-like portions 41, with shallower V-shaped grooves and a V-bending angle closer to 180° than in the case described with reference to FIG. 3. In this manner, a fin 40A having fin bent portions 42 is fabricated.

[0048] Next, the semi-finished heat exchanger 2 is bent as shown in FIG. 5 (step S4).

[0049] In this bending process, a punch (not shown) is pressed against the portion P1 shown in Fig. 7, which will become the above-mentioned bent portions 15 and 16, from the back surface side B where the above-mentioned fin bent portion 42 is formed. As a result, the semi-finished heat exchanger 2 is bent into an L shape.

[0050] At this time, since the fin bending portions 42 are located on the inner side of the bend, a compressive force is applied to the fin bending portions 42. This causes the fin bending portions 42 to bend further. As a result, the V-shaped grooves of the fin bending portions 42 deepen to the depth shown in FIG. 3. Furthermore, the bending angle of the V-shape of the fin bending portions 42 decreases to the angle shown in FIG. 3. This prevents the compressive force from concentrating on the heat transfer tube 20 during the bending process. As a result, deformation of the heat transfer tube 20 is suppressed. This prevents a decrease in the heat exchange efficiency of the heat exchanger 1A.

[0051] Furthermore, the deformation of the fins 40A is regular because only the V-shaped bending of the fin bends 42 changes, which reduces the variation in ventilation resistance between the fins 30 and reduces the heat exchange efficiency of the heat exchanger 1A.

[0052] When the semi-finished heat exchanger 2 is bent into an L shape, the V-shaped bend of the fin bend portion 42 is further bent. Also, L-shaped bend portions 15, 16 are formed in the straight tubular header. As a result, the heat exchanger 1A is manufactured, which includes the headers 11, 12 provided with the bend portions 15, 16. In this way, the heat exchanger 1A is completed.

[0053] In this disclosure, step S2 is also referred to as an assembly process for the semi-finished heat exchanger 2. Step S3 is also referred to as a manufacturing process or bending process for the heat exchanger 1A. Furthermore, the fin bent portion 42 is also referred to as a fallen portion because the plate-shaped portion 41 is fallen downward.

[0054] The straight-tube header 21 and the straight-tube header 22 produced in step S1 are examples of the first header having a first straight pipe portion and the second header having a second straight pipe portion, as defined in the present disclosure. The headers 11 and 12 described above are examples of the first header and the second header, as defined in the present disclosure. The bent portions 15 and 16 are examples of the first bent portion and the second bent portion, as defined in the present disclosure. The straight portions 17 and 18 are examples of the first straight portion and the second straight portion, as defined in the present disclosure. The fins 40A and 30 are examples of the first fin and the second fin, as defined in the present disclosure. The heat transfer tubes 20 at the bent portions 15 and 16 are examples of the first heat transfer tube, as defined in the present disclosure. The heat transfer tubes 20 at the straight portions 17 and 18 are examples of the second heat transfer tube, as defined in the present disclosure.

[0055] As described above, in the heat exchanger 1A according to the first embodiment, the fins 40A are attached to the heat transfer tubes 20 at the bent portions 15 and 16, and the fins 40A include the fin bent portions 42, which are low-strength portions. The fin bent portions 42 are less rigid than the other portions and are more likely to deform than the other portions when the spacing between adjacent heat transfer tubes changes. Therefore, when the spacing between the heat transfer tubes 20 changes during the bending process during the manufacture of the heat exchanger 1A, the fin bent portions 42 of the fins 40A located between the heat transfer tubes 20 deform before the other portions. As a result, compressive forces are less likely to concentrate on the heat transfer tubes 20, and deformation of the heat transfer tubes 20 is suppressed. Furthermore, because deformation of the heat transfer tubes 20 is suppressed, a decrease in the heat exchange efficiency of the heat exchanger 1A is suppressed.

[0056] Because the fin bent portions 42 are formed at the ends of the plate-like portions 41 of the fins 40A that face the inside of the bend, a compressive force is likely to be applied to them during the bending process. As a result, even if a compressive force is applied to the heat transfer tubes 20 during the bending process, the compressive force is likely to be concentrated at the fin bent portions 42, and is unlikely to be concentrated on the heat transfer tubes 20. Furthermore, in the heat exchanger 1A, deformation of the heat transfer tubes 20 can be suppressed simply by forming the fin bent portions 42 at the ends of the plate-like portions 41 that face the inside of the bend. This makes it easy to manufacture a heat exchanger 1A in which deformation of the heat transfer tubes 20 is suppressed.

[0057] Furthermore, the fin bending portion 42 is bent so that the plate-shaped portion 41 of the fin 40A protrudes toward one of the plate surfaces. As a result, the fin bending portion 42 changes the protrusion amount according to the compressive force in the bending process, thereby preventing the compressive force from concentrating on the heat transfer tube 20.

[0058] Furthermore, fin bent portion 42 is formed by bending plate-shaped portion 41 of fin 40A into a V shape, with the tip of the V pointing downward. Therefore, fin bent portion 42 can collect water droplets adhering to plate-shaped portion 41 at the tip of the V shape, allowing them to be drained with high efficiency.

[0059] Even when compressive force is applied during the bending process, the fin bent portion 42 maintains the V-shaped bent shape of the plate-shaped portion 41. Therefore, the fin 40A is less likely to experience increased ventilation resistance compared to when the fin 30 is irregularly deformed by the compressive force during the bending process. As a result, the fin 40A can maintain ventilation resistance within a certain range and prevent a decrease in the heat exchange efficiency of the heat exchanger 1A.

[0060] The heat transfer tube 20 may bend during the bending process. However, the heat transfer tube 20 may bend as long as it is not buckled. Figure 8 shows a heat transfer tube 20 that has been deformed into such a shape.

[0061] Fig. 8 is an enlarged rear view of a portion of the heat exchanger 1A when the heat transfer tube 20 included in a modification of the heat exchanger 1A according to embodiment 1 is bent. Fig. 8 shows the straight portions 17, 18 of the headers 11, 12 of the heat exchanger 1A as viewed from the inside of the bend after bending.

[0062] 8, the heat transfer tubes 20 connected to the straight portions 17, 18 of the headers 11, 12 may be bent convexly toward the −X side, i.e., toward the bent portions 15, 16. This occurs because the spacing between the heat transfer tubes 20 at the bent portions 15, 16 changes due to the bending process, and the heat transfer tubes 20 at the straight portions 17, 18 are pulled toward the bent portions 15, 16 and deformed.

[0063] This phenomenon of bending of the heat transfer tubes 20 occurs during uniform bending, in which a straight header is bent by supporting both sides of the longitudinal center and applying a load to the longitudinal center. In this uniform bending, bending may occur in the heat transfer tubes 20 at the straight sections 17 and 18 on both sides of the bent sections 15 and 16. It is also acceptable for the heat transfer tubes 20 at the straight sections 17 and 18 on both sides to bend.

[0064] Furthermore, when rotary draw bending is used, the heat transfer tubes 20 in the straight sections 17, 18 that are in the direction in which the clamps used in this processing method rotate do not bend, but the heat transfer tubes 20 in the straight sections 17, 18 that are on the opposite side of the direction in which the clamps rotate do bend. It is acceptable for the heat transfer tubes 20 in these positions to bend. Here, the rotary draw bending method is a method in which a portion of the straight tubular headers 21, 22 is clamped between a clamp and a cylindrical bending die, and the clamp is moved circumferentially around the bending die to rotate the clamp around the central axis of the bending die, thereby forming the bent sections 15, 16.

[0065] Furthermore, when a bending process is used, the heat transfer tubes 20 at the straight portions 17, 18 connected to the bent portions 15, 16 are bent, and the heat transfer tubes 20 at the straight portions 17, 18 on the other side of the bent portions 15, 16 are not bent. The heat transfer tubes 20 may be deformed into such shapes.

[0066] Furthermore, this phenomenon of bending of the heat transfer tubes 20 occurs not only at the straight sections 17 and 18 but also at the bent sections 15 and 16, but the bending of the heat transfer tubes 20 at the bent sections 15 and 16 is not as great as that of the heat transfer tubes 20 at the straight sections 17 and 18. Therefore, the heat transfer tubes 20 at the bent sections 15 and 16 do not need to bend as much as the heat transfer tubes 20 at the straight sections 17 and 18.

[0067] (Embodiment 2) In the first embodiment, the low-strength portion of each plate-like portion 41 of the fin 40A is formed by the fin bent portion 42. However, the low-strength portion is not limited to this. The low-strength portion may be any portion that has lower rigidity than other portions of the plate-like portion 41 and is more likely to deform than other portions when the spacing between adjacent heat transfer tubes 20 changes.

[0068] In a heat exchanger 1B according to the second embodiment, the low-strength portion of each plate-shaped portion 41 is formed by a portion of each plate-shaped portion 41 that includes a notch cut inward from the end face. The configuration of the heat exchanger 1B will be described below with reference to Fig. 9. The second embodiment will be described mainly with respect to the configuration different from the first embodiment.

[0069] Fig. 9 is an enlarged perspective view of a portion of the heat transfer tube 20 and the fins 40B included in the heat exchanger 1B according to embodiment 2. Similar to Fig. 3, Fig. 9 shows the heat transfer tube 20 connected to the bent portions 15 and 16 of the headers 11 and 12, and the fins 40B attached to the heat transfer tube 20. Although the fins 40B will be deformed by the compressive force applied in the bending process, Fig. 9 shows the fins 40B with little deformation to facilitate understanding.

[0070] In heat exchanger 1B, the low-strength portion is formed by a portion of plate-shaped portion 41 including cut portion 43 shown in Fig. 9, which cuts into the end face. In other words, the low-strength portion is formed by cut portion 43 and the peripheral portion of cut portion 43 of plate-shaped portion 41.

[0071] The notch 43 cuts into the plate-shaped portion 41 from the end face of the back side B of the plate-shaped portion 41 toward the inside of the plate-shaped portion 41. The notch 43 penetrates the plate-shaped portion 41. The notch 43 is formed in a wedge shape with the tip facing inward of the plate-shaped portion 41. That is, when viewed from a direction perpendicular to the plate surface of the plate-shaped portion 41, the notch 43 is formed in a triangular shape with its apex located inside the plate-shaped portion 41 and its opposite side located on the end face of the plate-shaped portion 41.

[0072] In detail, when the plate-like portion 41 is viewed from a direction perpendicular to the plate surface, the notches 43 are formed in the shape of an isosceles triangle with the base facing toward the inside of the bends 15 and 16 shown in FIG. 1 , i.e., toward the back surface side B. The compressive force applied in the bending process is greater toward the back surface side B than toward the neutral plane. The notches 43 have such a shape, which enables the fins 40B to deform in response to the compressive force. As a result, the notches 43 are deformed by the compressive force in the bending process, making it difficult for the compressive force to be applied to the heat transfer tube 20.

[0073] Furthermore, because cutouts 43 have the above-described shape, even if they are deformed by a compressive force, the end faces of cutouts 43 on plate-like portion 41 are less likely to overlap or protrude. As a result, cutouts 43 are less likely to cause large ventilation resistance.

[0074] Furthermore, the notches 43 cut the plate-shaped portion 41 into the above-described shape. That is, the notches 43 completely cut out the plate-shaped portion 41 in the thickness direction. As a result, the notches 43 facilitate deformation of the fin 40B by the compressive force applied in the bending process.

[0075] In this specification, the notch refers to a shape of a cut made from an end face of the plate-like portion 41 toward the inside. For this reason, the notch portion 43 is also called a cutout portion.

[0076] The manufacturing method of heat exchanger 1B is the same as the manufacturing method of heat exchanger 1A according to embodiment 1, except that (1) in step S1 described in embodiment 1, fins 40B are manufactured in the same manner as fins 30 are manufactured, (2) in manufacturing fins 40B, notches 43 are formed simultaneously with the molding of fins 40B, for example, by press working, and (3) as a result, step S3 described in embodiment 1 is omitted. Therefore, its description will be omitted. The notches 43 are triangular in shape because plate-like portions 41 are punched out by press working.

[0077] The above-mentioned cutout 43 is an example of a first cutout as defined in the present disclosure. The end surface of the back side B of the plate-like portion 41 on which the cutout 43 is formed is an example of either an end surface of the plate-like portion 41 facing the inner side of the bent first bent portion or an end surface of the plate-like portion 41 facing the outer side of the bent first bent portion as defined in the present disclosure. The fin 40B is an example of a first fin as defined in the present disclosure. The shape of the cutout 43 may also be called V-shaped.

[0078] As described above, in the heat exchanger 1B according to the second embodiment, the notches 43 are formed in the plate-shaped portions 41 of the fins 40B, and the portions of the plate-shaped portions 41 including the notches 43 function as low-strength portions. As a result, when a compressive force is applied to the heat transfer tubes 20 in the bending process during manufacturing, the portions of the plate-shaped portions 41 including the notches 43 deform before other portions of the plate-shaped portions 41. This makes it difficult for the compressive force to concentrate on the heat transfer tubes 20 in the heat exchanger 1B. Furthermore, the heat exchanger 1B can suppress deformation of the heat transfer tubes 20.

[0079] In the method for manufacturing the heat exchanger 1B, the cut portions 43 can be formed at the same time as the fins 40B are formed by, for example, pressing. Therefore, the heat exchanger 1B can be manufactured with the same number of steps as a normal heat exchanger whose fins do not have the cut portions 43.

[0080] (Variation) In the heat exchanger 1B according to the second embodiment, the cut portions 43 are triangular, but the cut portions 43 are not limited to this. It is sufficient that the portions of the plate-shaped portion 41 including the cut portions 43 have lower rigidity than the other portions of the plate-shaped portion 41 and are more easily deformed than the other portions of the plate-shaped portion 41 when the gap between adjacent heat transfer tubes 20 changes. The shape of the cut portions 43 is arbitrary within this range.

[0081] Fig. 10 is an enlarged perspective view of a portion of a modified example of heat exchanger 1B according to embodiment 2. Fig. 11 is an enlarged perspective view of a portion of another modified example of heat exchanger 1B according to embodiment 2. Note that Figs. 10 and 11 show the same portion of heat exchanger 1B as shown in Fig. 9.

[0082] 10, the cutout 43 may be rectangular. Specifically, the cutout 43 may be formed by cutting the plate-shaped portion 41 from an end face on the back side B to the front side F, and may have a rectangular shape with its longitudinal direction facing the front direction. In other words, the cutout 43 may be I-shaped with its longitudinal direction facing the front direction.

[0083] Furthermore, it is desirable that the width of cutout 43 in the short direction is smaller than the base of the isosceles triangle of cutout 43 described in embodiment 2. This is because, with this configuration, the area of ​​cutout plate portion 41 can be made smaller than in embodiment 2, thereby improving the heat exchange performance of fin 40B as much as possible.

[0084] Furthermore, as shown in Fig. 11, the cutout 43 may be semicircular. Specifically, the cutout 43 may have a center on the end face side of the plate-shaped portion 41 and have a semicircular shape with a convex arc facing inward of the plate-shaped portion 41. This configuration can prevent stress from concentrating on the interior angle of the cutout 43 during the bending process, which could cause the fin 40B to break or deform into an unintended shape. The semicircular arc may be a perfect circle or an ellipse.

[0085] Although not shown, the configuration shown in Fig. 11 may be applied to the second embodiment or the configuration shown in Fig. 10. That is, the interior angles of the triangular or rectangular cutout 43 may be rounded into a semicircular shape. In this case, the arc of the semicircular shape may be an arc corresponding to the angle of the interior angle.

[0086] 10 and 11 may be applied to Embodiment 1. That is, the fin bent portion 42 may have a notch 43 formed therein.

[0087] (Embodiment 3) In the first embodiment, the low-strength portion of each plate-shaped portion 41 of the fin 40A is formed by the fin bent portion 42. In the second embodiment, the low-strength portion is formed by a portion of the plate-shaped portion 41 including the cut portion 43. However, the low-strength portion is not limited to this. As explained in the second embodiment, the low-strength portion may be any portion that has lower rigidity than other portions of the plate-shaped portion 41 and is more likely to deform than other portions when the spacing between adjacent heat transfer tubes 20 changes.

[0088] In a heat exchanger 1C according to the third embodiment, each of the plate-shaped portions 41 has a low-strength portion formed by a thin-walled portion. The configuration of the heat exchanger 1C will be described below with reference to Fig. 12. The configuration of the third embodiment that differs from the first and second embodiments will be mainly described.

[0089] Fig. 12 is an enlarged perspective view of a portion of the heat transfer tube 20 and the fins 40C included in the heat exchanger 1C according to embodiment 3. Like Fig. 3, Fig. 12 shows the heat transfer tube 20 connected to the bent portions 15 and 16 of the headers 11 and 12, and the fins 40C attached to the heat transfer tube 20. Although the fins 40C are deformed by the compressive force applied in the bending process, Fig. 12 shows the fins 40C with little deformation, similar to Fig. 9, for ease of understanding.

[0090] As shown in FIG. 12, in a heat exchanger 1C, the low strength portion is formed by a thin portion 44 that is thinner than the other portion of a plate-shaped portion 41.

[0091] When viewed from a direction perpendicular to the plate surface of the plate-shaped portion 41, the thin-walled portion 44 is formed in a triangular shape with its apex located inside the plate-shaped portion 41 and its opposite side located on the end surface of the plate-shaped portion 41. That is, the thin-walled portion 44 is formed in a planar shape similar to that of the cutout portion 43 described with reference to FIG. 9. As a result, the outer shape of the thin-walled portion 44 when viewed from a direction perpendicular to the plate surface of the plate-shaped portion 41 is similar to that of the cutout portion 43 shown in FIG. 9. Therefore, a detailed description of the outer shape of the thin-walled portion 44 will be omitted. By having such a shape, the thin-walled portion 44 is deformed by the compressive force in the bending process, making it difficult for the compressive force to be applied to the heat transfer tube 20.

[0092] As described above, the thin-walled portions 44 are thinner than the other portions of the plate-shaped portion 41. The thickness of the thin-walled portions 44 is constant. Unlike the cut portions 43 described in the second embodiment, the thin-walled portions 44 transfer heat from the heat transfer tubes 20, thereby contributing to heat exchange. As a result, the fins 40C have a higher heat exchange efficiency than the fins 40B described in the second embodiment.

[0093] Although not shown in Fig. 12, the thin-walled portion 44 may be embossed on one side of the plate-like portion 41 by embossing. In this case, the direction in which the thin-walled portion 44 protrudes is preferably the direction of gravity, i.e., downward. Note that in Fig. 12, the thin-walled portions 44 that are symmetrical in the X direction are adjacent to each other in the vertical direction, but thin-walled portions 44 of the same shape may also be adjacent to each other in the vertical direction.

[0094] The manufacturing method of heat exchanger 1C is the same as the manufacturing method of heat exchanger 1A according to embodiment 1, except that (1) in step S1 described in embodiment 1, fins 40C are manufactured in the same manner as fins 30 are manufactured, and at the same time, thin-walled portions 44 are formed by, for example, press working while shaping fins 40C, and (2) as a result, step S3 described in embodiment 1 is omitted. Therefore, its description will be omitted.

[0095] The above-described thin-walled portion 44 is an example of a first thin-walled portion as defined in the present disclosure. The end face of the back side B of the plate-like portion 41 on which the thin-walled portion 44 is formed is an example of either an end face facing the inner side of the bent first bent portion or an end face facing the outer side of the bent first bent portion of the plate-like portion 41 as defined in the present disclosure. The fin 40C is an example of a first fin as defined in the present disclosure.

[0096] As described above, in the heat exchanger 1C according to the third embodiment, the fins 40C include the thin-walled portions 44, which are low-strength portions. As a result, when a compressive force is applied to the heat transfer tube 20 during the bending process during manufacturing, the thin-walled portions 44 deform before other portions of the plate-shaped portion 41. This makes it difficult for the compressive force to concentrate on the heat transfer tube 20. Furthermore, the heat exchanger 1C can suppress deformation of the heat transfer tube 20.

[0097] In the method for manufacturing heat exchanger 1C, similar to the second embodiment, the thin-walled portions 44 can be formed simultaneously with the formation of fins 40C by, for example, press working. Therefore, heat exchanger 1C can be manufactured with the same number of steps as a normal heat exchanger in which the fins do not have thin-walled portions 44.

[0098] (Variation) In the heat exchanger 1C according to the third embodiment, the thin-walled portions 44 have a triangular shape in plan view, but are not limited to this. For the same reasons as those described in the second embodiment, the shape of the thin-walled portions 44 is arbitrary as long as it satisfies the conditions for the low-strength portion.

[0099] Fig. 13 is an enlarged perspective view of a portion of a modified example of the heat exchanger 1C according to embodiment 3. Note that Fig. 13 shows the same portion of the heat exchanger 1C as shown in Fig. 12.

[0100] As shown in Fig. 13, the thin-walled portion 44 may have a semicircular shape. More specifically, the thin-walled portion 44 may have a semicircular shape with a center on the end face side of the plate-shaped portion 41 and a convex arc facing inward of the plate-shaped portion 41, similar to the embodiment shown in Fig. 11. With this embodiment, stress concentration during the bending process can be prevented, similar to the embodiment shown in Fig. 11. In this embodiment, the semicircular arc may also be an elliptical arc.

[0101] The thin-walled portion 44 of the third embodiment may be applied to the fin bent portion 42 of the fin 40A described in the first embodiment. For example, when the plate-shaped portion 41 is viewed from a direction perpendicular to the plate surface, the fin bent portion 42 has an isosceles triangular shape with its base facing the end face of the back side B of the plate-shaped portion 41, and the isosceles triangular shaped portion may be a thin-walled portion 44 that is thinner than the other portions of the plate-shaped portion 41. This is because such a thin-walled portion 44 is easier to bend, and therefore the fin bent portion 42 is more likely to deform.

[0102] (Fourth embodiment) In the second embodiment, the notches 43 are formed on the end surface of the plate-shaped portion 41 facing the inside of the bend. However, the form having the notches 43 is not limited to this. The notches may be formed in other parts of the plate-shaped portion 41.

[0103] In a heat exchanger 1D according to embodiment 4, notches 45 and 46 are formed in each of the plate-shaped portions 41. The configuration of the heat exchanger 1D will be described below with reference to Fig. 14. In embodiment 4, the configuration different from embodiments 1 to 3 will be mainly described.

[0104] Fig. 14 is an enlarged cross-sectional view of a portion of a fin 40D included in a heat exchanger 1D according to embodiment 4. The fin 40D shown in Fig. 14 is a fin attached to the bending portions 15 and 16 of the headers 11 and 12 included in the heat exchanger 1D, but for ease of understanding, the fin 40D is shown in an undeformed state before the headers 11 and 12 are bent in the bending process.

[0105] 14, in heat exchanger 1D, plate-like portion 41 of fin 40D is formed with notch 45 corresponding to notch 43 of embodiment 2 and notch 46 located at a different position from notch 45. Both notch 45 and 46 correspond to the low-strength portion described in embodiments 1-3.

[0106] As in the second embodiment, the notch 45 is formed on the end surface of the plate-shaped portion 41 facing the back side B. As in the notch 43 according to the modified example of the second embodiment, the notch 45 has a rectangular shape formed by cutting the plate-shaped portion 41 from the end surface of the back side B to the front side F, with the longitudinal direction facing the front direction. The tip of the notch 45 on the front side F is rounded into a semicircular shape. The notch 45 is formed on the end surface of the plate-shaped portion 41 facing the back side B, and by having such a shape, as in the second embodiment, the plate-shaped portion 41 is easily deformed by the compressive force in the bending process, making it difficult for the compressive force to be applied to the heat transfer tube 20.

[0107] In contrast, the notch 46 is formed on the end face of the plate-shaped portion 41 facing the front side F. That is, the notch 46 is formed on the end face opposite to the end face of the plate-shaped portion 41 on which the notch 45 is formed. The notch 46 has a shape obtained by inverting the notch 45 in the front direction. In other words, the notch 46 has a shape symmetrical to the notch 45 with respect to the line L1 indicating the neutral plane.

[0108] The heat exchanger 1D is manufactured by steps S1, S2, and S4, excluding step S3 described in the second embodiment. In the manufacturing method of the second embodiment, in step S2, when each fin 40B is sandwiched between heat transfer tubes 20, the end faces of the fins 40B on which the notches 43 are formed are aligned. In contrast, in the manufacturing method of the heat exchanger 1D according to the fourth embodiment, the notches 45 and 46 are formed on each of the two opposing surfaces of the plate-like portion 41. Therefore, in step S2, the end faces of the fins 40D on which the notches 45 are formed do not need to be aligned in the same direction. The end face on which the notches 45 and the end face on which the notches 46 are formed may be oriented in the same direction. As a result, the manufacturing method of the heat exchanger 1D can improve the efficiency of the manufacturing process.

[0109] Furthermore, when the semi-finished heat exchanger 2 is bent in step S4 of the manufacturing method for heat exchanger 1D, a compressive force is applied to the end face of the plate-shaped portion 41 facing the inside of the bend, and a tensile force is applied to the end face of the plate-shaped portion 41 facing the outside of the bend. In contrast, in heat exchanger 1D, notches 45 are provided on the end face of the plate-shaped portion 41 facing the inside of the bend, and notches 46 are provided on the end face of the plate-shaped portion 41 facing the outside of the bend. As a result, when the semi-finished heat exchanger 2 is bent in step S4, the plate-shaped portion 41 is deformed so that notches 45 are compressed and notches 46 are tensile. Thus, according to the manufacturing method for heat exchanger 1D, compressive and tensile forces are less likely to be applied to the heat transfer tubes 20. As a result, deformation of the heat transfer tubes 20 is suppressed. Furthermore, a decrease in the heat exchange efficiency of the heat exchanger 1D can be suppressed.

[0110] The above-mentioned cut portions 45 and 46 are an example of a first cut portion and a second cut portion as defined in the present disclosure. The end surface of the plate-shaped portion 41 facing the back side B on which the cut portion 45 is formed is an example of either an end surface of the plate-shaped portion 41 facing the inner side of the bent portion of the first bent portion or an end surface of the plate-shaped portion 41 facing the outer side of the bent portion of the first bent portion as defined in the present disclosure. The end surface of the plate-shaped portion 41 facing the front side F on which the cut portion 46 is formed is an example of the other end surface of the plate-shaped portion 41 facing the inner side of the bent portion of the first bent portion or an end surface of the plate-shaped portion 41 facing the outer side of the bent portion of the first bent portion as defined in the present disclosure.

[0111] As described above, in the heat exchanger 1D according to the fourth embodiment, the plate-like portions 41 of the fins 40D each have the notch portions 45 and the notch portions 46 that are symmetrical in shape and arrangement to the notch portions 46. As a result, when assembling a heat exchanger 1D using a plurality of fins 40D, the heat exchanger 1D can be assembled with the orientation of the fins 40D reversed. As a result, in the manufacturing method of the heat exchanger 1D, the work of aligning the orientation of the fins 40D can be omitted, and assembly efficiency can be improved.

[0112] Furthermore, in the heat exchanger 1D, deformation of the heat transfer tubes 20 can be suppressed, as in the second embodiment.

[0113] (Variation) In the fourth embodiment, the cuts 45 and 46 are rectangular. However, the shape of the cuts 45 and 46 is not limited to this. For the same reasons as those described in the second embodiment, the shape of the cuts 45 and 46 may be any shape that satisfies the conditions for the low strength portion. Furthermore, the shapes of the cuts 45 and 46 may be any shape that is symmetrical with respect to the neutral plane. For example, the cuts 45 and 46 may be triangular or semicircular as described in the second embodiment and the modified example of the second embodiment.

[0114] In the fourth embodiment, the case where the low-strength portions are the cut portions 45 and 46 is described, but the fourth embodiment is also applicable to the case where the low-strength portions are the thin-walled portions 44. In particular, the cut portion 45 may be replaced with the thin-walled portion 44, and the cut portion 46 may be replaced with the thin-walled portion 44 that is symmetrical with respect to the neutral plane. In this case, the thin-walled portion 44 that is symmetrical with respect to the neutral plane is an example of the second thin-walled portion defined in the present disclosure.

[0115] Moreover, the fourth embodiment is also applicable to a case where the low strength portion is the fin bent portion 42. In detail, the notch portion 45 may be replaced with the fin bent portion 42, and the notch portion 46 may be replaced with the fin bent portion 42 that is symmetrical with respect to the neutral plane.

[0116] (Embodiment 5) In the first embodiment, the low-strength portion of each plate-shaped portion 41 of the fin 40A is formed by the fin bent portion 42. In the second embodiment, the low-strength portion is formed by a portion of the plate-shaped portion 41 including the cut portion 43. In the third embodiment, the low-strength portion is formed by the thin-walled portion 44. However, the low-strength portion is not limited to this. As described above, the low-strength portion may be any portion that has lower rigidity than other portions of the plate-shaped portion 41 and is more likely to deform than other portions when the spacing between adjacent heat transfer tubes 20 changes.

[0117] In a heat exchanger 1E according to embodiment 5, each plate-like portion 41 has a low-strength portion formed by a bending portion 47. The configuration of the heat exchanger 1E will be described below with reference to Fig. 15. The configuration of embodiment 5 that differs from embodiments 1 to 4 will be mainly described.

[0118] Fig. 15 is an enlarged perspective view of a portion of the heat transfer tube 20 and the fins 40E included in the heat exchanger 1E according to embodiment 5. Like Fig. 3, Fig. 15 shows the heat transfer tube 20 connected to the bent portions 15 and 16 of the headers 11 and 12, and the fins 40E attached to the heat transfer tube 20. Although the fins 40E are deformed by the compressive force applied in the bending process, Fig. 15, like Figs. 9 and 12, shows the fins 40E that are not deformed by the bending process for ease of understanding.

[0119] As shown in FIG. 15, in the heat exchanger 1E, the low strength portion is formed by a bending portion 47 that is more bent than the other portions of the plate-shaped portion 41.

[0120] The corrugated peaks 401 and valleys 402 of the fin 40E are brazed to the heat transfer tube 20. Two flexures 47 are provided on each of the peaks 401 and valleys 402, sandwiching the brazed portions of the peaks 401 and valleys 402. By providing the flexures 47 in these positions, the widths W1 and W2 of the corrugated peaks 401 and valleys 402 are greater than half the wavelength L2 of the corrugated shape. Furthermore, although the flexures 47 are provided on the rear side B in FIG. 15 , the flexures 47 actually extend from the rear side B to the front side F (not shown). By providing the flexures 47 in this shape and position, they are deformed by compressive and tensile forces during the bending process, preventing damage to the fin 40E itself. Furthermore, the flexures 47 also reduce the likelihood of compressive and tensile forces being applied to the heat transfer tube 20.

[0121] The method for manufacturing the heat exchanger 1E is the same as the method for manufacturing the heat exchanger 1A according to the first embodiment, except for (1) that the fins 40E having the bending portions 47 are fabricated in step S1 described in the first embodiment, and (2) that, as a result, step S3 described in the first embodiment is omitted. Therefore, the description thereof will be omitted.

[0122] As described above, in the heat exchanger 1E according to the fifth embodiment, the fins 40E include the flexible portions 47, which are low-strength portions. As a result, when a compressive or tensile force is applied to the heat transfer tube 20 during the bending process during manufacturing, the flexible portions 47 deform before other portions of the plate-like portion 41. This makes it difficult for the compressive or tensile force to concentrate on the heat transfer tube 20. As a result, deformation of the heat transfer tube 20 is suppressed.

[0123] In particular, when a tensile force is applied, the plate-shaped portion 41 may be pulled beyond its allowable limit and broken, but according to the heat exchanger 1E, the flexible portion 47 provides room for expansion, so the fins 40E themselves are less likely to break.

[0124] Although the heat exchanger 1A-1E and the method for manufacturing the heat exchanger 1A-1E according to the embodiment of the present disclosure have been described above, the heat exchanger 1A-1E and the method for manufacturing the heat exchanger 1A-1E are not limited to this.

[0125] In embodiments 1-5, fins 40A-40E having low-strength portions are attached to the heat transfer tubes 20 connected to the bent portions 15, 16 of the headers 11, 12, respectively. In other words, fins 40A-40E are attached to all of the heat transfer tubes 20 at the bent portions 15, 16. However, the heat exchanger 1A-1E is not limited to this. In the heat exchanger 1A-1E, it is sufficient that at least one of the fins attached to the heat transfer tubes 20 connected to the bent portions 15, 16 has a low-strength portion. In short, it is sufficient that at least one of the fins is fin 40A-40E.

[0126] Fig. 16 is a development view of a modified example of the heat exchanger 1A according to embodiment 1. Fig. 17 is a development view of another modified example of the heat exchanger 1A according to embodiment 1. Figs. 16 and 17 show the heat exchanger 1A when the bent portions 15 and 16 of the modified example and the other modified example are linearly developed. The parts corresponding to the bent portions 15 and 16 developed linearly are designated by the symbol P4.

[0127] 16, in portions P4 of headers 11 and 12 corresponding to bending portions 15 and 16, fins 40A having low-strength portions and fins 30 having no low-strength portions may be arranged alternately in the arrangement direction of heat transfer tubes 20. In this configuration, fins 30 that are less likely to deform than fins 40A during the bending process and therefore more likely to maintain ventilation performance are arranged in bending portions 15 and 16, thereby improving the ventilation performance of heat exchanger 1A.

[0128] 17, a plurality of fin groups may be formed in portions P4 of headers 11 and 12 corresponding to bent portions 15 and 16, each of which includes fins 30 without low-strength portions arranged continuously in the arrangement direction of heat transfer tubes 20. Fins 40A may be disposed between the fin groups. As described above, fins 30 are less likely to deform than fins 40A during the bending process, and as a result, ventilation performance is more easily maintained. Therefore, the ventilation performance of heat exchanger 1A can be improved compared to the first embodiment.

[0129] In this way, it is sufficient that at least one fin 40A-40E is disposed at the bent portions 15, 16. This is because, in the heat exchangers 1A-1E, deformation of the heat transfer tube 20 can be suppressed, and a decrease in heat exchange efficiency can be suppressed.

[0130] In embodiments 1-4, the low-strength portions are provided on end surfaces of the plate-shaped portions 41 of the fins 40A that face the inside of the bend. However, the locations at which the low-strength portions are provided are not limited thereto. The low-strength portions may be provided on at least one of the end surfaces of the plate-shaped portions 41 that face the inside of the bend of the bent portions 15 and the end surfaces that face the outside of the bend of the bent portions 15. If the low-strength portions are provided at such positions, when the spacing between the heat transfer tubes 20 changes during the bending process in manufacturing the heat exchangers 1A-1D, for example, when the spacing between the heat transfer tubes 20 narrows or widens during the bending process, the low-strength portions are preferentially deformed, and it is possible to suppress the concentration of compressive or tensile forces on the heat transfer tubes 20.

[0131] Furthermore, in embodiments 1-5, the fins 40A-40E do not protrude beyond the heat transfer tubes 20 toward the rear side B, and do not protrude beyond the heat transfer tubes 20 toward the front side F. However, the shape of the fins 40A-40E is not limited to this. The fins 40A-40E may protrude beyond the heat transfer tubes 20 toward the rear side B. Alternatively, the fins 40A-40E may protrude beyond the heat transfer tubes 20 toward the front side F.

[0132] Fig. 18 is a cross-sectional view of yet another modified example of the fin 40A included in the heat exchanger 1A according to embodiment 1. Fig. 18 shows a cross-section of the modified example of the heat transfer tube 20 and the fin 40A, which are positioned so as to overlap the bent portions 15 and 16 in the vertical direction. Hatching has been omitted to facilitate understanding.

[0133] As shown in FIG. 18, the fins 40A may protrude further toward the front side F than the tip of the flattened cross-sectional shape of the heat transfer tube 20 on the front side F. That is, they may protrude toward the outside of the bends 15 and 16. The front side F of the fins 40A shown in FIG. 18 corresponds to the outside of the bend, and is the side into which outside air flows when the outdoor unit is in heating operation. For this reason, frost is easily formed on the front side F of the fins 40A. By protruding toward the front side F beyond the heat transfer tube 20, the fins 40A increase the area on which frost accumulates in areas prone to frost, thereby suppressing a decrease in heat exchange performance. Furthermore, the fins 40A have such a shape, which increases the heat transfer area and improves heat exchange performance.

[0134] Furthermore, as shown in FIG. 18 , the fins 40A may protrude further toward the rear surface side B than the base end of the flat cross-sectional shape of the heat transfer tube 20, which is located on the rear surface side B. That is, they may protrude toward the inner side of the bends 15 and 16. The distance D1 by which the fins 40A protrude may be the same as or shorter than the distance D2 by which the fins 40A protrude toward the front surface side F. The fins 40A have such a shape, which increases the area on which frost adheres and suppresses a decrease in heat exchange performance. In addition, the increased heat transfer area improves heat exchange performance.

[0135] In the embodiment shown in Figure 18, the fins 40A protrude to both the outside and inside of the bent portions 15 and 16, but it is preferable that the fins 40A protrude to at least one of the outside and inside of the bent portions 15 and 16.

[0136] In addition, in the first to fifth embodiments, the fins 30 and the fins 40A-40E are corrugated. However, the fins 30 and the fins 40A-40E are not limited to this. The fins 30 and the fins 40A-40E may be any fins that are provided between adjacent heat transfer tubes 20 and transfer heat from the heat transfer tubes 20.

[0137] Furthermore, in the first to fifth embodiments, the heat transfer tube 20 is a flat tube, but the heat transfer tube 20 is not limited to this. The heat transfer tube 20 may be any tube that connects at least the bent portions 15 and 16. Therefore, the heat transfer tube 20 may be, for example, a circular tube.

[0138] In the embodiments 1-5, an example is described in which the heat exchanger 1A-1E is incorporated into the outdoor unit of an air conditioner, but the heat exchanger 1A-1E is not limited to this. The heat exchanger 1A-1E can be applied to any device or equipment that requires heat exchange. For example, the heat exchanger 1A may be incorporated into the indoor unit of an air conditioner.

[0139] The orientations of the heat exchangers 1A-1E described in the embodiments 1-5, such as the vertical and horizontal directions, are for convenience in explaining the embodiments and may be changed as long as the positional relationship between the components of the heat exchangers 1A-1E is maintained.

[0140] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure. (Appendix 1) a first header having a first bent portion and a first linear portion extending from the first bent portion; a second header having a second bent portion bent in the same direction as the first bent portion and facing the first bent portion, and a second linear portion extending from the second bent portion; a plurality of first heat transfer tubes arranged along the first bent portion and connecting the first bent portion and the second bent portion; a plurality of fins provided between adjacent first heat transfer tubes, the fins transferring heat from the first heat transfer tubes; Equipped with At least one of the plurality of fins has a low-strength portion that is lower in rigidity than other portions of the fin and is more likely to deform than the other portions when the interval between adjacent first heat transfer tubes changes. heat exchanger. (Appendix 2) the fins each have a plate-shaped portion extending from one of the first heat transfer tubes to the other of the adjacent first heat transfer tubes, the low-strength portion is provided in a portion of the plate-shaped portion including at least one end surface of the first bent portion facing the inside of the bent portion and the end surface of the first bent portion facing the outside of the bent portion, 10. The heat exchanger of claim 1. (Appendix 3) The low-strength portion has a fin bent portion in which the plate-shaped portion is bent into a shape that protrudes toward one plate surface. 10. A heat exchanger as described in Appendix 2. (Appendix 4) the one plate surface of the plate-shaped portion faces the gravity direction, and the fin bent portion protrudes in the gravity direction; 10. A heat exchanger as described in Appendix 3. (Appendix 5) The low-strength portion has a first notch portion cut from either an end surface of the plate-shaped portion facing the inside of the bent portion or an end surface of the first bent portion facing the outside of the bent portion toward the inside of the plate-shaped portion. 5. The heat exchanger of any one of claims 2 to 4. (Appendix 6) The first cutout portion has any one of a triangular, rectangular, and semicircular shape when viewed from a direction perpendicular to the plate surface of the plate-shaped portion. 6. The heat exchanger of claim 5. (Appendix 7) The low-strength portion has the first notch portion and a second notch portion cut from the other end face of the plate-shaped portion, either an end face facing the inside of the bent first bent portion or an end face facing the outside of the bent first bent portion, toward the inside of the plate-shaped portion. 7. The heat exchanger of claim 5 or 6. (Appendix 8) the low-strength portion is provided at a position in contact with either an end surface of the plate-like portion facing the inside of the bent portion or an end surface of the first bent portion facing the outside of the bent portion, and has a first thin-walled portion having a thickness smaller than that of other portions of the plate-like portion. 8. The heat exchanger of any one of claims 2 to 7. (Appendix 9) When viewed from a direction perpendicular to the plate surface of the plate-shaped portion, the first thin-walled portion has a triangular shape with an apex located inside the plate-shaped portion and an opposite side to the apex located on the end surface of the plate-shaped portion, or has a semicircular shape with a center on the end surface side of the plate-shaped portion and a convex arc facing toward the inside of the plate-shaped portion. 10. The heat exchanger of claim 8. (Appendix 10) The low-strength portion has the first thin-walled portion and a second thin-walled portion provided at a position in contact with the other end surface of the plate-like portion, either an end surface facing the inside of the bent portion or an end surface facing the outside of the bent portion, and having a thickness smaller than that of other portions of the plate-like portion. 10. The heat exchanger of claim 8 or 9. (Appendix 11) the fin has a plate-like portion formed in a corrugated shape that undulates from one side of the first heat transfer tube to the other side of the adjacent first heat transfer tube, the low strength portion is provided on the plate-like portion and has a flexure portion shaped to make a width of a peak portion or a valley portion of the corrugation larger than half the wavelength of the corrugation. 10. The heat exchanger of claim 1. (Appendix 12) the fin protrudes beyond the first heat transfer tube to at least one of an inner side and an outer side of the first bent portion. 12. The heat exchanger of any one of claims 1 to 11. (Appendix 13) All of the plurality of fins have the low strength portion. 13. The heat exchanger of any one of claims 1 to 12. (Appendix 14) The plurality of fins are configured by a first fin having the low strength portion and a second fin not having the low strength portion. 13. The heat exchanger of any one of claims 1 to 12. (Appendix 15) The first fins and the second fins are arranged alternately in the gaps between the first heat transfer tubes aligned in the arrangement direction of the first heat transfer tubes. 15. The heat exchanger of claim 14. (Appendix 16) the second fins are provided in a plurality of successive positions in the gaps between the first heat transfer tubes arranged in the arrangement direction of the first heat transfer tubes, thereby forming a plurality of fin groups each successively arranged in the arrangement direction of the first heat transfer tubes; The first fin is disposed between the fin groups. 15. The heat exchanger of claim 14. (Appendix 17) further comprising a plurality of second heat transfer tubes arranged along the first straight portion and connecting the first straight portion and the second straight portion; At least one of the plurality of second heat transfer tubes is bent in a convex shape toward the side where the first bent portion and the second bent portion are located. 17. The heat exchanger of any one of claims 1 to 16. (Appendix 18) a step of assembling a semi-finished heat exchanger comprising: a first header having a first straight pipe portion; a second header having a second straight pipe portion parallel to the first straight pipe portion; a plurality of first heat transfer tubes arranged along the first straight pipe portion and connecting the first straight pipe portion and the second straight pipe portion; and a plurality of fins provided between adjacent first heat transfer tubes and transferring heat from the first heat transfer tubes, wherein at least one of the plurality of fins has a low-strength portion that is less rigid than other portions of the fin itself and is more easily deformed than the other portions when the spacing between adjacent first heat transfer tubes changes; a step of fabricating a heat exchanger in which the first header has a first bent portion and the second header has a second bent portion by bending the first straight pipe portion of the first header and the second straight pipe portion of the second header included in the semi-finished heat exchanger in the same direction; Equipped with In the step of fabricating the heat exchanger, the first straight pipe portion of the first header and the second straight pipe portion of the second header are bent, thereby changing the interval between adjacent first heat transfer tubes and deforming the low-strength portion. A method for manufacturing a heat exchanger.

[0141] This application is based on Japanese Patent Application No. 2022-42358, filed on March 17, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-42358 are incorporated herein by reference. [Explanation of symbols]

[0142] 1A, 1B, 1C, 1D, 1E heat exchanger, 2 semi-finished heat exchanger, 11, 12 header, 13, 14 connection part, 15, 16 bent part, 17, 18 straight part, 20 heat transfer tube, 21, 22 straight tubular header, 30 fin, 40A, 40B, 40C, 40D, 40E fin, 41 plate part, 42 fin bent part, 43 notch part, 44 thin part, 45, 46 notch part, 47 deflection part, 50 fin before processing, 401 peak part, 402 valley part, 421, 422, 424 fold, 423 apex, A1, A2 tube axis, B back side, C1 center, D1, D2 distance, F front side, L1 line, L2 Wavelength, P1, P2, P3, P4 portion, W1, W2 width.

Claims

1. a first header having a first bent portion and a first linear portion extending from the first bent portion; a second header having a second bent portion bent in the same direction as the first bent portion and facing the first bent portion, and a second linear portion extending from the second bent portion; a plurality of first heat transfer tubes arranged along the first bent portion and connecting the first bent portion and the second bent portion; a plurality of second heat transfer tubes arranged along the first straight portion and connecting the first straight portion and the second straight portion; a plurality of fins provided between adjacent first heat transfer tubes and between adjacent second heat transfer tubes, the fins transferring heat from the first heat transfer tubes and the second heat transfer tubes; Equipped with at least one of the plurality of fins has a low-strength portion that is lower in rigidity than other portions of the fin and is more likely to deform than the other portions when the interval between adjacent first heat transfer tubes changes, At least one of the plurality of second heat transfer tubes is bent in a convex shape toward a side where the first bent portion and the second bent portion are located. heat exchanger.

2. the fins each have a plate-shaped portion extending from one of the first heat transfer tubes to the other of the adjacent first heat transfer tubes, the low-strength portion is provided in a portion of the plate-shaped portion including at least one end surface of the first bent portion facing the inside of the bent portion and the end surface of the first bent portion facing the outside of the bent portion, The heat exchanger of claim 1 .

3. The low-strength portion has a fin bent portion in which the plate-shaped portion is bent into a shape that protrudes toward one plate surface.

3. The heat exchanger of claim 2.

4. the one plate surface of the plate-shaped portion faces the gravity direction, and the fin bent portion protrudes in the gravity direction; 4. The heat exchanger according to claim 3.

5. The low-strength portion has a first notch portion cut from either an end surface of the plate-shaped portion facing the inside of the bent portion or an end surface of the first bent portion facing the outside of the bent portion toward the inside of the plate-shaped portion.

3. The heat exchanger of claim 2.

6. The first cutout portion has any one of a triangular, rectangular, and semicircular shape when viewed from a direction perpendicular to the plate surface of the plate-shaped portion.

6. The heat exchanger according to claim 5.

7. The low-strength portion has the first notch portion and a second notch portion cut from the other end face of the plate-shaped portion, either an end face facing the inside of the bent first bent portion or an end face facing the outside of the bent first bent portion, toward the inside of the plate-shaped portion.

7. The heat exchanger according to claim 5 or 6.

8. the low-strength portion is provided at a position in contact with either an end surface of the plate-like portion facing the inside of the bent portion or an end surface of the first bent portion facing the outside of the bent portion, and has a first thin-walled portion having a thickness smaller than that of other portions of the plate-like portion.

3. The heat exchanger of claim 2.

9. When viewed from a direction perpendicular to the plate surface of the plate-shaped portion, the first thin-walled portion has a triangular shape with an apex located inside the plate-shaped portion and an opposite side to the apex located on the end surface of the plate-shaped portion, or has a semicircular shape with a center on the end surface side of the plate-shaped portion and a convex arc facing toward the inside of the plate-shaped portion.

9. The heat exchanger of claim 8.

10. The low-strength portion has the first thin-walled portion and a second thin-walled portion provided at a position in contact with the other end surface of the plate-like portion, either an end surface facing the inside of the bent portion or an end surface facing the outside of the bent portion, and having a thickness smaller than that of other portions of the plate-like portion.

10. The heat exchanger according to claim 8 or 9.

11. the fin has a plate-like portion formed in a corrugated shape that undulates from one side of the first heat transfer tube to the other side of the adjacent first heat transfer tube, the low strength portion is provided on the plate-like portion and has a flexure portion shaped to make a width of a peak portion or a valley portion of the corrugation larger than half the wavelength of the corrugation. The heat exchanger of claim 1 .

12. the fin protrudes beyond the first heat transfer tube to at least one of an inner side and an outer side of the first bent portion.

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

13. All of the plurality of fins have the low strength portion.

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

14. The plurality of fins are configured by a first fin having the low strength portion and a second fin not having the low strength portion.

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

15. The first fins and the second fins are arranged alternately in the gaps between the first heat transfer tubes aligned in the arrangement direction of the first heat transfer tubes.

15. The heat exchanger of claim 14.

16. the second fins are provided in a plurality of successive positions in the gaps between the first heat transfer tubes arranged in the arrangement direction of the first heat transfer tubes, thereby forming a plurality of fin groups each successively arranged in the arrangement direction of the first heat transfer tubes; The first fin is disposed between the fin groups.

15. The heat exchanger of claim 14.

17. a step of assembling a semi-finished heat exchanger comprising: a first header having a first straight pipe portion; a second header having a second straight pipe portion parallel to the first straight pipe portion; a plurality of heat transfer tubes arranged along the first straight pipe portion and connecting the first straight pipe portion and the second straight pipe portion; and a plurality of fins provided between adjacent heat transfer tubes to transfer heat of the heat transfer tubes, wherein at least one of the plurality of fins has a low-strength portion that is less rigid than other portions of the fin itself and is more likely to deform than the other portions when the spacing between the adjacent heat transfer tubes changes; a step of fabricating a heat exchanger in which the first header has a first bent portion and a first linear portion extending from the first bent portion, and the second header is bent in the same direction as the first bent portion, and the second header has a second bent portion opposite the first bent portion and a second linear portion extending from the second bent portion; Equipped with In the step of fabricating the heat exchanger, by bending the first straight pipe portion of the first header and the second straight pipe portion of the second header, the interval between adjacent heat transfer tubes changes and the low strength portion is deformed, At least one of the heat transfer tubes connecting the first straight portion and the second straight portion among the plurality of heat transfer tubes is bent in a convex shape toward a side where the first bent portion and the second bent portion are located. A method for manufacturing a heat exchanger.

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