Heat exchanger

Abstract

This heat exchanger (27) comprises: a plurality of fins (43) that are disposed at interval in the thickness direction; and a plurality of flat cross-sectional shape heat transfer pipes (41) that respectively extend through the plurality of fins (43) in the thickness direction and are disposed at intervals in a direction perpendicular to the thickness direction. Each fin (43) is provided with: a plurality of cutout portions (53) that extend in an insertion direction orthogonal to the direction in which the plurality of heat transfer pipes (41) are disposed, and into which at least a portion of the heat transfer pipes (41) are inserted; and a plurality of pipe peripheral beads (55) that are offset in the thickness direction of the fins (43) and follow the flat cross-sectional shape of the heat transfer pipes (41) along each of the plurality of cutout portions (53).

Description

heat exchanger

[0001] FIELD An embodiment of the present invention relates to a heat exchanger.

[0002] There exists a fin-tube heat exchanger that includes a plurality of fins arranged at intervals from one another in the thickness direction, and a plurality of heat transfer tubes with a flat cross section that extend in the direction in which the fins are arranged, penetrate each of the fins in the thickness direction, and are arranged at intervals from one another in a direction perpendicular to the direction in which the fins are arranged.

[0003] Japanese Patent Application Laid-Open No. 2021-196158

[0004] During operation, water generated by condensation may adhere to the surfaces of the fins and heat transfer tubes of the heat exchanger of an air conditioner. This water reduces the heat exchange efficiency of the heat exchanger and must be quickly drained from the heat exchanger. However, in heat transfer tubes with a flat cross-sectional shape, water tends to remain around the heat transfer tube due to its cross-sectional shape.

[0005] SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a heat exchanger having excellent drainage properties.

[0006] In order to solve the above problem, a heat exchanger according to an embodiment of the present invention comprises a plurality of fins arranged at intervals in a thickness direction, and a plurality of heat transfer tubes with a flat cross-sectional shape that extend through each of the plurality of fins in the thickness direction and are arranged at intervals in a direction perpendicular to the thickness direction, wherein each of the fins has a plurality of notches that extend in an insertion direction perpendicular to the up-down direction when the direction in which the plurality of heat transfer tubes are arranged is defined as the up-down direction, and into which at least a portion of the heat transfer tube is inserted, and a plurality of circumferential beads that are offset in the thickness direction of the fin and follow the cross-sectional shape of the heat transfer tube along each of the plurality of notches.

[0007] It is preferable that the circumferential beads of the heat exchanger according to an embodiment of the present invention include a first circumferential bead arranged along the upper longitudinal edge of the cutout, a second circumferential bead arranged along the lower longitudinal edge of the cutout, and a curved third circumferential bead that connects the first circumferential bead and the second circumferential bead and is arranged along the terminal edge of the cutout.

[0008] The circumferential bead of the heat exchanger according to an embodiment of the present invention has a circumferential bead flat portion that intersects with the flat surface of the heat transfer tube, and the heat exchanger preferably satisfies the following relational expression (1), where W (millimeters) is the shortest distance from the notch to the outer periphery of the circumferential bead flat portion, TH (millimeters) is the distance between the opposing flat surfaces, and TP (millimeters) is the distance between adjacent notches: 0.5 millimeters<W<(TP-TH)÷3 (1)

[0009] Each of the fins of the heat exchanger according to the embodiment of the present invention has a flat portion that is a portion excluding the plurality of cutouts and the plurality of circumferential beads, and the heat exchanger preferably satisfies the following relational expression (2), where H (millimeters) is the offset between the flat portion and the flat portion of the circumferential bead, and FP (millimeters) is the spacing between the plurality of fins: 0.1 millimeters<H<FP÷2 (2)

[0010] Each of the fins of the heat exchanger according to an embodiment of the present invention is provided by cutting and raising a portion of the fin, and has at least one cut-and-raised portion that contacts an adjacent fin, and a hollow portion that penetrates the fin in the thickness direction when the at least one cut-and-raised portion is cut and raised. The at least one cut-and-raised portion has a support portion that contacts the adjacent fin, and a connection portion that connects the support portion and a surface of the fin. An imaginary line that passes through the center of the heat transfer tube in the width direction and extends in the up-down direction is defined as a first imaginary line VL1, and an imaginary line that passes through the center between adjacent heat transfer tubes and extends parallel to the width direction of the heat transfer tube is defined as a second imaginary line VL2. 2, a virtual line that passes through the center between the uppermost and lowermost ends of the hollow portion and extends parallel to the width direction of the heat transfer tube is defined as a third virtual line VL3, and a line segment that is a part of the third virtual line VL3 and overlaps with the hollow portion is defined as a virtual line segment VLS. Preferably, the at least one cut-and-raised portion includes the virtual line segment VLS in a divided region in the region S between the adjacent heat transfer tubes, which is on the terminal side of the notch across the first virtual line VL1 and on the upper heat transfer tube side across the second virtual line, and the support portion and the connection portion include a first cut-and-raised portion that is provided to be located below the third virtual line VL3.

[0011] The circumferential bead of the heat exchanger according to an embodiment of the present invention has a circumferential bead flat portion that intersects with the flat surface of the heat transfer tube, and the heat exchanger preferably satisfies the following relational expression (3), where D1 is the shortest distance between the outer circumferential edge of the circumferential bead flat portion and the terminal end of the notch, D2 is the shortest horizontal distance between the outer circumferential edge of the circumferential bead flat portion and the hollow portion, and D3 is the shortest distance from the edge of the fin that extends in the vertical direction and is located closer to the terminal end of the notch to the terminal end of the notch: D1<D2<D3 (3)

[0012] It is preferable that the hollow portion of the heat exchanger according to an embodiment of the present invention is part of the cutout portion, and that the at least one cutout portion includes a second cutout portion provided on at least one of the upper longitudinal edge of the cutout portion and the lower longitudinal edge of the cutout portion.

[0013] In the heat exchanger according to the embodiment of the present invention, it is preferable that the following relational expression (4) be satisfied, where L1 is the length of the side of the support portion extending in the vertical direction, L2 is the cut-and-raised length of the connection portion, and L3 is the length of the side of the cavity portion extending in the vertical direction: L1 + L2 < L3 (4)

[0014] Each of the fins of the heat exchanger according to the embodiment of the present invention is provided in a region S between adjacent heat transfer tubes by cutting and raising a portion of the fin, and has a plurality of louvers arranged parallel to the insertion direction of the cutout portion, a virtual line passing through the center of the heat transfer tube in the width direction and extending in the up-down direction is defined as a first virtual line VL1, a region on the terminal side of the cutout portion with respect to the first virtual line VL1 in the region S is defined as a region S1, and a region on the open end side of the cutout portion is defined as a region S2, and each of the plurality of louvers provided in the region S1 is defined as a When the louvers in area S1 are defined as first louvers and each of the louvers provided in area S2 are defined as second louvers, it is preferable that each of the first louvers is inclined at an angle θ (°) with respect to the surface of the fin, and each of the second louvers is inclined at an angle 180-θ (°) with respect to the surface of the fin, and that each of the first louvers is provided over 50 percent or more of the area of ​​area S1, and that each of the second louvers is provided over 50 percent or more of the area of ​​area S2.

[0015] It is preferable that each of the fins of the heat exchanger according to an embodiment of the present invention has a rib extending in the vertical direction, which is provided in the region between the edge of the fin extending in the vertical direction and closer to the end of the notch, and the end of the notch.

[0016] The present invention provides a heat exchanger with excellent drainage properties.

[0017] Schematic diagrams of a refrigeration cycle apparatus including a heat exchanger according to an embodiment of the present invention. (A) Schematic diagram of a heat exchanger according to an embodiment of the present invention. (B) View as viewed from the arrow A in Fig. 2(A). (A) Cross-sectional view taken along B-B in Fig. 2(A). (B) Enlarged cross-sectional view taken along C-C in Fig. 3(A). (C) Perspective view showing a portion of a fin included in a heat exchanger according to an embodiment of the present invention. (D) Perspective view showing a portion of another example of a fin included in a heat exchanger according to an embodiment of the present invention. (A) Perspective view showing at least one cut-and-raised portion of a fin included in a heat exchanger according to an embodiment of the present invention. (B) Plan view showing at least one cut-and-raised portion of a fin included in a heat exchanger according to an embodiment of the present invention. (A) A plan view showing multiple louvers on a fin provided in a heat exchanger according to an embodiment of the present invention; (B) A cross-sectional view taken along the line D-D in FIG. 5(A); (C) A cross-sectional view taken along the line E-E in FIG. 5(A); (D) A view of FIG. 5(A) from the back; (E) A perspective view of FIG. 5(A); (F) A perspective view of FIG. 5(D).

[0018] The heat exchanger according to this embodiment will be described with reference to Figures 1 to 5. Note that the same or corresponding components in the drawings are denoted by the same reference numerals.

[0019] FIG. 1 is a schematic diagram of a refrigeration cycle device 1 including a heat exchanger 27 according to an embodiment of the present invention.

[0020] As shown in FIG. 1 , a refrigeration cycle device 1 including a heat exchanger 27 according to this embodiment is configured as an air conditioner, and includes an indoor unit 3 and an outdoor unit 5 .

[0021] The indoor unit 3 includes an indoor unit housing 11, an indoor heat exchanger 13 housed in the indoor unit housing 11, and an indoor blower 15 that generates a flow of air passing through the indoor heat exchanger 13.

[0022] The outdoor unit 5 includes an outdoor unit housing 21, a compressor 23 housed in the outdoor unit housing 21, a four-way valve 25 housed in the outdoor unit housing 21, a heat exchanger 27 that is an outdoor heat exchanger housed in the outdoor unit housing 21, an expansion device 29, and an outdoor blower 31 housed in the outdoor unit housing 21 and that generates a flow of air (outdoor air) that passes through the heat exchanger 27. The expansion device 29 is, for example, an electronic expansion valve (Pulse Motor Valve, PMV).

[0023] The refrigeration cycle device 1 includes a refrigerant pipe 33 that sequentially connects the compressor 23, the four-way valve 25, the heat exchanger 27, the expansion device 29, and the indoor heat exchanger 13 to allow the refrigerant to flow.

[0024] The operation of the refrigeration cycle device 1 is switched by switching the flow path of the four-way valve 25, switching between cooling operation of the refrigeration cycle device 1, in which the refrigerant flows as shown by the dashed lines in Figure 1, and heating operation of the refrigeration cycle device 1, in which the refrigerant flows as shown by the solid lines.

[0025] During cooling operation, the high-temperature, high-pressure gas-phase refrigerant compressed by the compressor 23 of the refrigeration cycle apparatus 1 is sent to the heat exchanger 27 via the four-way valve 25. The heat exchanger 27 exchanges heat between the outdoor air and the refrigerant, condensing the refrigerant into a high-pressure liquid phase. In other words, the heat exchanger 27 functions as a condenser. The refrigerant that has passed through the heat exchanger 27 passes through the expansion device 29, where it is decompressed and becomes a low-pressure two-phase gas-liquid refrigerant, and reaches the indoor heat exchanger 13. The indoor heat exchanger 13 exchanges heat between the indoor air and the two-phase gas-liquid refrigerant, cooling the air to be blown into the indoor space while evaporating the refrigerant and transitioning it from the two-phase gas-liquid state to the gas phase. In other words, the indoor heat exchanger 13 functions as an evaporator. The refrigerant that has passed through the indoor heat exchanger 13 is sucked back into the compressor 23.

[0026] During heating operation, the refrigeration cycle apparatus 1 reverses the four-way valve 25 to cause a refrigerant flow in the refrigeration cycle in the opposite direction to the refrigerant flow during cooling operation. In other words, the indoor heat exchanger 13 functions as a condenser, and the heat exchanger 27 functions as an evaporator. High-temperature, high-pressure gas-phase refrigerant compressed by the compressor 23 of the refrigeration cycle apparatus 1 is sent to the indoor heat exchanger 13 via the four-way valve 25. The indoor heat exchanger 13 exchanges heat between the indoor air and the refrigerant, warming the air to be blown into the indoor space while condensing the refrigerant to a high-pressure liquid phase. In other words, the indoor heat exchanger 13 functions as a condenser. The refrigerant that passes through the indoor heat exchanger 13 passes through the expansion device 29 to be decompressed into a low-pressure two-phase gas-liquid refrigerant, which then reaches the outdoor heat exchanger 27. The outdoor heat exchanger 27 exchanges heat between the outdoor air and the two-phase gas-liquid refrigerant, evaporating the refrigerant and transitioning it from the two-phase gas-liquid state to the gas phase. That is, the outdoor heat exchanger 27 functions as an evaporator. The refrigerant that has passed through the outdoor heat exchanger 27 is sucked back into the compressor 23.

[0027] During heating operation, when the refrigerant evaporates in the heat exchanger 27, heat is absorbed from the outside air by the refrigerant. At this time, water vapor in the outside air condenses into droplets that adhere to the heat exchange members of the heat exchanger 27. The adhered moisture may freeze and form frost due to the low temperature of the outside air. The frost may interfere with heat exchange and reduce the heat exchange rate. Therefore, the refrigeration cycle apparatus 1 performs a defrosting operation to remove frost.

[0028] During defrosting operation, the refrigeration cycle apparatus 1 sets the four-way valve 25 to the same state as during cooling operation, and refrigerant flows in the same order as during cooling operation. At this time, the refrigeration cycle apparatus 1 stops both the indoor blower 15 and the outdoor blower 31, and heats the heat exchange members of the heat exchanger 27 with the high-temperature, high-pressure gas-phase refrigerant delivered from the compressor 23. In this way, the refrigeration cycle apparatus 1 melts the frost on the heat exchanger 27. The melted water flows downward on the surface of the heat exchange members of the heat exchanger 27 due to the action of gravity, and is discharged, for example, from a drain hole on the bottom of the outdoor unit 5.

[0029] FIG. 2A is a schematic diagram showing a heat exchanger 27 according to an embodiment of the present invention, and FIG. 2B is a view taken along the arrow A in FIG. 2A.

[0030] 2A and 2B, the heat exchanger 27 according to this embodiment is a fin-tube heat exchanger. The heat exchanger 27 has, for example, a rectangular plate-like appearance. The heat exchanger 27 includes a plurality of fins 43, a plurality of heat transfer tubes 41, and headers 45 and 47.

[0031] The fins 43 are arranged at intervals in the thickness direction. The heat transfer tubes 41 extend through the fins 43 and are arranged at intervals in the vertical direction. The thickness direction of the fins 43 is substantially the same as the stacking direction of the fins 43.

[0032] The headers 45, 47 are arranged parallel to each other and spaced apart in the stacking direction of the fins 43. The headers 45, 47 circulate the refrigerant through the heat transfer tubes 41 installed between them. The headers 45, 47 may be, for example, stacked headers formed by stacking rectangular plates, or may be header pipes that are straight pipes with a circular cross section (annular cross section).

[0033] The air undergoing heat exchange by the heat exchanger 27 flows in the direction of the arrow FL in Fig. 2(B) . In other words, the air undergoing heat exchange by the heat exchanger 27 flows in the short direction of the fins 43. The direction in which the air undergoing heat exchange by the heat exchanger 27 flows is referred to as the "air flow direction FL" of the heat exchanger 27.

[0034] The heat exchanger 27 divides the refrigerant that has flowed into one of the headers 45, 47 from the refrigerant pipe 33 (see FIG. 1 ), for example, into the plurality of heat transfer tubes 41. While flowing through the heat transfer tubes 41, the refrigerant exchanges heat with the outside air flowing between the fins 43, and condenses or evaporates depending on the operation mode of the refrigeration cycle apparatus 1 equipped with the heat exchanger 27. The heat exchanger 27 merges the refrigerant after condensation or evaporation in the other header 47, 45, and causes the refrigerant to flow out again into the refrigerant pipe 33 (see FIG. 1 ).

[0035] The heat transfer tubes 41, the fins 43, and the headers 45 and 47 are typically made of aluminum or an aluminum alloy, and are typically integrated with the heat transfer tubes 41, the fins 43, and the headers 45 and 47 by brazing.

[0036] Figure 3(A) is a cross-sectional view taken along line B-B of Figure 2(A), Figure 3(B) is an enlarged cross-sectional view taken along line C-C of Figure 3(A), Figure 3(C) is a perspective view showing a portion of the fin 43 provided in the heat exchanger 27 according to an embodiment of the present invention, and Figure 3(D) is a perspective view showing a portion of another example of the fin 43 provided in the heat exchanger 27 according to an embodiment of the present invention.

[0037] 3A, some of the heat transfer tubes 41 have been removed for ease of explanation of each component. In actual use, the heat exchanger 27 is installed so that the multiple heat transfer tubes 41 are aligned in the longitudinal direction of the fins 43. In other words, the heat exchanger 27 is installed so that the multiple fins 43 are aligned horizontally and the multiple heat transfer tubes 41 are aligned vertically. In this embodiment, the vertical direction coincides with the vertical direction.

[0038] As shown in Figures 3(A) to 3(D) in addition to Figures 2(A) and 2(B), the heat transfer tubes 41 are flat tubes having a flat, rounded rectangular cross section. The heat transfer tubes 41 are arranged at substantially equal intervals in the X direction, which is the extension direction of the headers 45, 47. The heat transfer tubes 41 are substantially perpendicular to the headers 45, 47. Ends of each of the heat transfer tubes 41 are inserted into and fixed to the headers 45, 47. The heat transfer tubes 41 extend in the thickness direction of the fins 43.

[0039] The cross-sectional shape of the heat transfer tubes 41 extends in the air flow direction FL of the heat exchanger 27. In other words, the long sides of the cross-sectional shape of the heat transfer tubes 41 extend in the short direction of the fins 43. The direction of the long sides of the cross-sectional shape of the heat transfer tubes 41, i.e., the longitudinal direction of the cross-sectional shape of the heat transfer tubes 41, is substantially the same as the width direction of the heat transfer tubes 41. The short sides of the cross-sectional shape of the heat transfer tubes 41 extend in the direction in which the heat transfer tubes 41 are lined up, i.e., the extension direction of the headers 45, 47 (X direction). The length dimension of the short sides of the cross-sectional shape of the heat transfer tubes 41 is substantially the same as the thickness dimension of the heat transfer tubes 41. A pair of adjacent heat transfer tubes 41 have their wide surfaces, i.e., flat surfaces 41a, facing each other in the extension direction of the long sides of the cross-sectional shape.

[0040] Each heat transfer tube 41 has a plurality of refrigerant flow passages 51 aligned in the air flow direction FL of the heat exchanger 27. In other words, each heat transfer tube 41 has a plurality of refrigerant flow passages 51 aligned in the width direction of the heat transfer tube 41. The plurality of refrigerant flow passages 51 extend substantially parallel to the extension direction of the heat transfer tube 41. One end of each of the plurality of refrigerant flow passages 51 is connected to one header 45, and the other end is connected to the other header 47. The heat transfer tubes 41 are generally manufactured by extruding aluminum.

[0041] The fins 43 are thin plates having the same rectangular shape. Each fin 43 is a molded product formed by pressing a metal plate. The fins 43 are arranged at substantially equal intervals in the extension direction of the heat transfer tubes 41. The long sides of the fins 43 extend vertically, and the short sides of the fins 43 extend in the air flow direction FL. The length of the short sides of the fins 43 is usually longer than the length of the heat transfer tubes 41 in the width direction. If the dimension of the fins 43 defined in the extension direction of the heat transfer tubes 41 is the thickness, the thickness of the fins 43 is smaller than the length of the short sides and the length of the long sides.

[0042] The fins 43 have a plurality of notches 53 extending in the short side direction of the fins 43, an insertion direction perpendicular to the direction in which the heat transfer tubes 41 are arranged, and into which at least a portion of the heat transfer tubes 41 is inserted. The notches 53 are provided at intervals from one another in the vertical direction, i.e., the longitudinal direction of the fins 43. The heat transfer tubes 41 are inserted into the notches 53 formed in each of the fins 43 and brazed to the fins 43 in a heat transferable manner, thereby increasing the heat transfer area of ​​the heat transfer tubes 41.

[0043] The notches 53 are formed along the cross-sectional shape or outer shape of the heat transfer tubes 41. In other words, the shape of the notches 53 is long in the short-side direction of the fins 43. The length dimension of the notches 53 in the short-side direction is approximately the same as the thickness dimension of the heat transfer tubes 41. Furthermore, the length of the notches 53 in the longitudinal direction, i.e., the length in the insertion direction of the heat transfer tubes 41, is usually approximately the same as the length of the heat transfer tubes 41 in the width direction.

[0044] The cutout 53 has an open end 53a that opens at one longitudinal edge 43a of the fin 43 that extends in a direction perpendicular to the air flow direction FL, and an end 53b that is closed at the other longitudinal edge 43b of the fin 43. The open end 53a of the cutout 53 may have a heat transfer tube introduction portion 53c that increases in length in the lateral direction of the cutout 53 toward the one longitudinal edge 43a, in order to make it easier to insert the heat transfer tube 41.

[0045] The notch 53 is formed, for example, by punching out the fin 43 in the thickness direction of the fin 43 at the portion where the notch 53 is to be formed before the fin 43 is formed.

[0046] However, in a heat transfer tube with a flat cross-sectional shape, water tends to remain around the heat transfer tube due to its cross-sectional shape. In particular, water that flows down the surface of the fins tends to remain at the contact points between the heat transfer tube and the fins.

[0047] Therefore, each fin 43 has a plurality of circumferential beads 55 that are offset in the thickness direction of the fin 43 and follow the cross-sectional shape of the heat transfer tube 41 along each of the plurality of cutouts 53, and a flat portion 57 that is the portion of the fin 43 excluding the plurality of cutouts 53 and the plurality of circumferential beads 55.

[0048] The multiple circumferential beads 55 are offset to one side in the thickness direction of the fin 43 with respect to the flat plate portion 57. In other words, the multiple circumferential beads 55 protrude from one flat surface 57a of the flat plate portion 57, as shown in Figures 3(A) to 3(C). Alternatively, the multiple circumferential beads 55 may protrude from the other flat surface (not shown) of the flat plate portion 57, as shown in Figure 3(D). Water adhering to the fin 43 flows along the shape of the circumferential beads 55.

[0049] The circumferential bead 55 may have a circumferential bead connecting portion 58 that connects the circumferential bead 55 and the flat portion 57. The circumferential bead connecting portion 58 is formed at an angle so as to connect the raised portion of the circumferential bead 55, i.e., the circumferential bead flat portion 56 (described later) and the flat portion 57. Water adhering to the fin 43 flows along the shapes of the circumferential bead 55 and the circumferential bead connecting portion 58.

[0050] The flat plate portions 57 are drainage regions on the surface of the fins 43. The flat plate portions 57 join together the water that has flowed down via the respective circumferential beads 55. In other words, the spaces between adjacent fins 43 in the extension direction of the heat transfer tube 41 become flow paths for the water that has flowed down via the respective circumferential beads 55.

[0051] The multiple circumferential beads 55 and flat plate portions 57 cooperate to expel water that has migrated to the upper surfaces of the heat transfer tubes 41 and their vicinity. Specifically, water generated by condensation on the surfaces of the heat transfer tubes 41 and fins 43 of the heat exchanger 27 flows along the surfaces of the fins 43 and condenses repeatedly, moving to the upper flat surfaces 41a of the heat transfer tubes 41 and their vicinity. The water that has migrated to the upper flat surfaces 41a of the heat transfer tubes 41 and their vicinity flows along the circumferential beads 55 near the heat transfer tubes 41 and along the circumferential bead connections 58. In other words, the circumferential beads 55 capture and collect water that tends to accumulate around the heat transfer tubes 41. The flat plate portions 57 allow the water collected by the respective circumferential beads 55 to flow downward while repeatedly merging.

[0052] In addition, the circumferential bead 55 may include a first circumferential bead 55a arranged along the upper edge 53d in the longitudinal direction of the cutout 53, i.e., the insertion direction of the heat transfer tube 41, a second circumferential bead 55b arranged along the lower edge 53e in the longitudinal direction of the cutout 53, and a curved third circumferential bead 55c that connects the first circumferential bead 55a and the second circumferential bead 55b and is arranged along the terminal edge 53f, which is the edge of the terminal end 53b of the cutout 53.

[0053] The first circumferential bead 55a collects water that has migrated to the upper flat surface 41a of the heat transfer tube 41 and prevents the water from accumulating on the upper flat surface 41a of the heat transfer tube 41. The first circumferential bead 55a may be provided over the entire upper edge 53d of the cutout 53, or may be provided on a portion of the upper edge 53d excluding the vicinity of the open end 53a of the cutout 53, for example.

[0054] The second circumferential bead 55b collects water that has reached the lower side of the heat transfer tube 41 and prevents the water from accumulating on the lower flat surface 41a of the heat transfer tube 41. The second circumferential bead 55b may be provided over the entire lower edge 53e of the cutout 53, or may be provided on a portion of the lower edge 53e excluding the vicinity of the open end 53a of the cutout 53, for example.

[0055] The third circumferential bead 55c collects water that has flowed along the first circumferential bead 55a and water that has moved to the side of the heat transfer tube 41, i.e., near the end 53b of the cutout portion 53, and guides the collected water downward due to its curved shape.

[0056] The circumferential bead 55 may have a circumferential bead flat portion 56 that intersects with the flat surface 41a of the heat transfer tube 41. In this case, the heat exchanger 27 preferably satisfies the following relational expression (1), where W (millimeters (mm)) is the shortest distance from the notch 53 to the outer periphery 56a of the circumferential bead flat portion 56 of the circumferential bead 55, TH (millimeters (mm)) is the distance between the opposing flat surfaces 41a of the heat transfer tube 41, i.e., the thickness of the heat transfer tube 41, and TP (millimeters (mm)) is the distance between adjacent notches 53: 0.5 millimeters<(shortest distance W)<((distance TP)-(distance TH))÷3 (1)

[0057] Furthermore, it is more preferable that the heat exchanger 27 satisfies the following relational expression (1)': 1 millimeter < (shortest distance W) < ((distance TP) - (distance TH)) ÷ 4 (1)'

[0058] More precisely, the distance TP is the distance between the imaginary lines VLt of adjacent notches 53, where VLt is an imaginary line that passes through the center of the notch 53 in the short direction and extends parallel to the longitudinal direction (horizontal direction) of the notch 53. The distances TP and TH can be set appropriately depending on, for example, the specifications of the heat exchanger 27. The distance TP is, for example, a value within a range of 10 to 15 millimeters. The distance TH is, for example, a value within a range of 1 to 3 millimeters.

[0059] By setting the shortest distance W within the range of relational expression (1), in other words the width of the circumferential bead flat portion 56, the circumferential bead 55 improves the water collection effect. Furthermore, by setting the shortest distance W within the range of relational expression (1)', the circumferential bead 55 further improves the water collection effect. In the process of finding relational expressions (1) and (1)', the inventors conducted the following analysis of the drainage performance in the heat exchanger 27.

[0060] As an example of the analysis, the region P in Fig. 3(A) was used as the analysis region, and the heat exchanger 27 was in a state where heat transfer tubes 41 were inserted into all of the cutouts 53 in the region P. Also, as shown in Fig. 3(B), the rising angle θb of the circumferential bead 55 relative to the flat plate portion 57 was set to 150°, and the offset amount H of the circumferential bead flat portion 56 relative to the flat plate portion 57 was set to 0.5 millimeters. The rising angle θb is the angle of the circumferential bead connecting portion 58 connecting the circumferential bead 55 and the flat plate portion 57.

[0061] Furthermore, in the initial state, water was applied to the surface of the fin 43 in the region P, and the total amount of water was set to 1. Then, over time, water was discharged from the lower end of the region P, and the remaining amount of water (residual water rate) on the surface of the fin 43 in the region P was calculated by changing the condition of the shortest distance W.

[0062] The minimum distance W was set to 1.0 mm, 1.5 mm, and 2.0 mm as the condition for the minimum distance W. Furthermore, for comparison, the amount of water remaining on the surface of the fin when the fin does not have the circumferential bead 55 and the circumferential bead flat portion 56 was also calculated.

[0063] As a result of the analysis, the difference in dissolution residual water rate became clear. The residual water rate 0.4 seconds after the initial state was as follows for each condition of the shortest distance W and when there was no circumferential bead flat portion 56. When the shortest distance W was 1.0 mm, the residual water rate was 0.713. When the shortest distance W was 1.5 mm, the residual water rate was 0.683. When the shortest distance W was 2.0 mm, the residual water rate was 0.695. And when there was no circumferential bead flat portion 56, the residual water rate was 0.749. The inventors found that under the above-mentioned specified analysis conditions, the residual water rate was lowest and drainage performance was improved when the circumferential bead 55 had a circumferential bead flat portion 56 and the shortest distance W, which is the width of the circumferential bead flat portion 56, was 1.5 mm.

[0064] The circumferential bead flat portion 56 does not need to have the shortest distance W as a uniform width, and may have a non-uniform width as long as the shortest distance W is greater than 0.5 millimeters, which is the lower limit of relational expression (1), and smaller than (TP-TH) / 3, which is the upper limit of relational expression (1). The surface of the circumferential bead flat portion 56 does not need to be uniformly flat, and may have at least one or more recesses (not shown) and / or at least one or more protrusions (not shown), for example.

[0065] Furthermore, when the spacing between the fins 43 in the stacking direction is FP (millimeters (mm)), the offset amount H preferably satisfies the range of the following relational expression (2): 0.1 millimeters<(offset amount H)<(spacing FP)÷2 (2)

[0066] If the offset amount H is 0.1 millimeters or less, the water collection effect of the circumferential bead 55 is excessively reduced, and water may easily move over the flat portion 56 of the circumferential bead and toward the heat transfer tube 41. On the other hand, if the offset amount H is (spacing FP) / 2 or more, it may be difficult to form the circumferential bead 55 on the fin 43 without distortion by press working, depending on the material and thickness of the fin 43. Therefore, as long as the offset amount H is within the range of the above relational expression (2), the circumferential bead 55 exhibits water collection without impairing processability and manufacturability.

[0067] Figure 4(A) is an oblique view showing at least one raised portion 59 of a fin 43 provided in a heat exchanger 27 according to an embodiment of the present invention, and Figure 4(B) is a plan view showing at least one raised portion 59 of a fin 43 provided in a heat exchanger 27 according to an embodiment of the present invention.

[0068] 4A and 4B show only a portion of the fin 43. This also applies to the figures described below. For ease of explanation, adjacent heat transfer tubes 41 are attached to the fin 43 in FIG. 4B.

[0069] As shown in Figures 4(A) and 4(B), each fin 43 may have at least one cut-out portion 59 formed by cutting out a portion of the fin 43 and in contact with an adjacent fin 43, and a hollow portion 61 that penetrates the thickness of the fin 43 when the at least one cut-out portion 59 is cut out.

[0070] At least one cut-and-raised portion 59 contacts an adjacent fin 43, thereby maintaining the spacing FP between the multiple fins 43 in the stacking direction. In other words, at least one cut-and-raised portion 59 maintains the spacing FP and suppresses deflection of the fins 43. Furthermore, the heat exchanger 27 can be assembled with the multiple fins 43 arranged at the spacing FP. In other words, the assembly of the heat exchanger 27 can be performed by inserting fewer heat transfer tubes 41 than the number of fins 43 into the cutouts 53 of the fins 43, thereby significantly reducing the number of steps compared to attaching each fin 43 to each heat transfer tube 41.

[0071] In the examples of Figures 4(A) and 4(B), at least one raised portion 59 is raised on the surface of the fin 43 opposite to the surface on which the circumferential bead 55 is raised, but it may also be raised on the surface on the same side as the surface on which the circumferential bead 55 is raised.

[0072] At least one cut-and-raised portion 59 is provided integrally with a hollow portion 61. In other words, at least one cut-and-raised portion 59 and a hollow portion 61 are provided as a pair, and the number of at least one cut-and-raised portion 59 is the same as the number of hollow portions 61. Furthermore, at least one cut-and-raised portion 59 has a support portion 63 that contacts the adjacent fin 43, and a connection portion 65 that connects the support portion 63 to the surface of the fin 43.

[0073] The support portions 63 are usually in surface contact with adjacent fins 43, maintaining the spacing FP between the fins 43 in the stacking direction. The support portions 63 are perpendicular to the connecting portions 65 and extend vertically downward from the connecting portions 65. The side of the support portions 63 that extends vertically downward is usually the short side of the support portions 63. The support portions 63 are cut and raised together with the connecting portions 65 as a single long plate during the manufacturing process of the cut-and-raised portions 59. A portion of the cut-and-raised long plate is cut from its tip so that its longitudinal length is an appropriate length. The support portions 63 are formed by pressing a jig against the long plate after the tip has been cut, and folding the long plate halfway.

[0074] The connecting portion 65 is cut and raised from a part of the fin 43 so as to be substantially perpendicular to the flat portion 57 of the fin 43. The side of the connecting portion 65 that extends perpendicular to the flat portion 57 of the fin 43 is the cut-and-raised length of the connecting portion 65. The cut-and-raised length of the connecting portion 65 is approximately the same as the spacing FP between adjacent fins 43 in the stacking direction. The connecting portion 65 is cut and raised as a single long plate together with the support portion 63 in the manufacturing process of the cut-and-raised portion 59. The connecting portion 65 is the portion that remains cut and raised without being folded when a jig is pressed against the long plate after the tip has been cut and the long plate is folded back partway.

[0075] The shape of the cavity 61 is usually a rectangle with long sides extending in the vertical direction. However, the shape of the cavity 61 is not limited to this shape, and may be, for example, a trapezoid with long sides of different lengths extending in the vertical direction, or a shape other than a rectangle. Furthermore, the cavity 61 may be provided at an angle with respect to the vertical direction.

[0076] Since the hollow portion 61 is a through-hole, it does not have surface tension. Therefore, water that has moved around the hollow portion 61 in the flat plate portion 57 of the fin 43 moves so as to avoid the hollow portion 61. In other words, the hollow portion 61 controls the flow of water that has moved around the hollow portion 61. By defining the positions of the hollow portion 61 and at least one cut-and-raised portion 59 paired with the hollow portion 61 based on their positional relationship with the heat transfer tube 41, it is expected that drainage around the heat transfer tube 41 will be improved.

[0077] Therefore, it is preferable that at least one of the raised portions 59 includes a first raised portion 59a whose position is determined by its positional relationship with the following three virtual straight lines and one virtual line segment in the fin 43:

[0078] 4(B), a first imaginary line VL1 is an imaginary line that passes through the center of the width of the heat transfer tube 41 and extends vertically. A second imaginary line VL2 is an imaginary line that passes through the center between adjacent heat transfer tubes 41, i.e., the center between the lower flat surface 41a of the heat transfer tube 41 located vertically above and the upper flat surface 41a of the heat transfer tube 41 located vertically below, and extends parallel to the width of the heat transfer tube 41. A third imaginary line VL3 is an imaginary line that passes through the center between the uppermost end 61a and the lowermost end 61b of the cavity 61 in the vertical direction and extends parallel to the width of the heat transfer tube 41. A line segment that is part of the third imaginary line VL3 and overlaps with the cavity 61 is an imaginary line segment VLS.

[0079] Furthermore, the region between adjacent heat transfer tubes 41, i.e., the region surrounded by the lower flat surface 41a of the heat transfer tube 41 located vertically above, the upper flat surface 41a of the heat transfer tube 41 located vertically below, and an imaginary line (not shown) connecting the ends 53b of adjacent cutout portions 53 in the vertical direction, is defined as region S. In this case, the first cut-and-raised portion 59a is included in a divided region of region S that is on the side of the ends 53b of the cutout portions 53 with respect to the first imaginary line VL1 and on the side of the upper heat transfer tube 41 in the vertical direction with respect to the second imaginary line VL2, and the imaginary line segment VLS is included in the divided region, and the support portion 63 and the connection portion 65 are positioned vertically below the third imaginary line VL3. In other words, the first cut-and-raised portion 59a and the hollow portion 61 paired with the first cut-and-raised portion 59a are disposed in a specific region below the lower flat surface 41a of the heat transfer tube 41 located vertically above in the region S. The hollow portion 61 blocks water moving below the lower flat surface 41a of the heat transfer tube 41 located vertically above the adjacent heat transfer tube 41, thereby preventing water from entering the region S.

[0080] Furthermore, the heat exchanger 27 preferably satisfies the following relational expression (3): (shortest distance D1) < (horizontal shortest distance D2) < (shortest distance D3) (3) where D1 is the shortest distance between the outer peripheral edge 56a of the circumferential bead flat portion 56 and the terminal end 53b of the notch 53, D2 is the shortest horizontal distance between the outer peripheral edge 56a of the circumferential bead flat portion 56 and the windward end 61c of the cavity 61 paired with the first raised portion 59a, and D3 is the shortest distance from the other edge 43b of the fin 43 closer to the terminal end 53b of the notch 53 to the terminal end 53b of the notch 53.

[0081] If the first raised portion 59a and the circumferential bead 55 located vertically above and closest to the first raised portion 59a are too close to each other horizontally, the first raised portion 59a may obstruct the flow of water collected by the circumferential bead 55. In other words, if the first raised portion 59a and the circumferential bead 55 are not positioned in an appropriate positional relationship, drainage performance may be reduced. By satisfying the above-mentioned relational expression (3), the heat exchanger 27 optimizes the drainage path in the flat portion 57 by positioning the first raised portion 59a and the circumferential bead 55 in an appropriate positional relationship.

[0082] 4(B), the shortest distance D1 is substantially the same as the shortest distance W, i.e., the width of the circumferential bead flat portion 56. More precisely, the shortest horizontal distance D2 is the shortest horizontal distance between the outer peripheral edge 56b, which is the windward end of the outer peripheral edge 56a of the circumferential bead flat portion 56, and the windward end 61c of the hollow portion 61 that pairs with the first cut-and-raised portion 59a.

[0083] Furthermore, the cavity 61 of the fin 43 may be part of the cutout 53, and at least one cutout 59 may include a second cutout 59b provided on at least one of the upper edge 53d and the lower edge 53e of the cutout 53. When the cavity 61 is part of the cutout 53, the length of the long side of the cavity 61 may be considered to be substantially the same as the length of the cutout 53 in the short direction.

[0084] The second raised portions 59b contact the adjacent fins 43 at their support portions 63, and together with the first raised portions 59a, more reliably maintain the spacing FP in the stacking direction of the multiple fins 43. Moreover, the second raised portions 59b are provided in a manner that leaves a portion that would normally be cut off in the process of providing at least one notch 53 in the fin 43. In other words, the second raised portions 59b are provided by effectively utilizing a portion of the fin 43 that would otherwise be discarded.

[0085] 4(A) and 4(B), the connecting portion 65 of the second raised portion 59b is formed integrally with a fin collar 67. When forming the notch 53 in the fin 43, the fin collar 67 is formed to protrude in the punching direction from the upper edge 53d, the lower edge 53e, and the terminal edge 53f that surround the notch 53. The fin collar 67 guides the insertion of the heat transfer tube 41 into the notch 53 and supports the heat transfer tube 41 after insertion.

[0086] Furthermore, when the length of the vertically extending side of the support portion 63 of at least one cut-and-raised portion 59 is L1, the cut-and-raised length of the connection portion 65 of at least one cut-and-raised portion 59 is L2, and the length of the vertically extending side of the hollow portion 61 is L3, the heat exchanger 27 preferably satisfies the following relational expression (4): (length L1) + (length L2) < (length L3) (4)

[0087] In the manufacturing process of the cut-and-raised portion 59, the long side of the cut-and-raised elongated plate coincides with the long side of the hollow portion 61. If the elongated plate is excessively long in the longitudinal direction (vertical direction), it may be difficult to control the bending at the appropriate position when a jig is pressed against the plate. Furthermore, even if the support portion 63 and the connecting portion 65 are formed by bending the elongated plate while it is still excessively long, the length L1 of the vertical side of the support portion 63 will remain excessively long. A support portion 63 with an excessively long length L1 may easily get caught on other fins 43, which may hinder the transportation of the fins 43 and the manufacturing of the heat exchanger 27. Therefore, the tip of the cut-and-raised elongated plate is cut to a length that allows the elongated plate to be reliably bent at the appropriate position. The support portion 63 and the connecting portion 65 are formed by pressing a jig against the shortened elongated plate. At this time, the above-mentioned relational expression (4) is established. Furthermore, the position at which the cut and raised long plate is bent is usually determined by the interval FP. In other words, the cut and raised length L2 of the connecting portion 65 is determined by the interval FP. Therefore, cutting the tip of the cut and raised long plate to shorten the long plate essentially means shortening the length L1 of the side extending in the vertical direction of the support portion 63.

[0088] As long as the relational expression (4) is satisfied, the first cut-and-raised portion 59a and the second cut-and-raised portion 59b may have different lengths L1 of the vertically extending sides of the respective support portions 63, and may also have different cut-and-raised lengths L2 of the respective connection portions 65. Furthermore, the length L3 of the vertically extending side of the hollow portion 61 paired with the first cut-and-raised portion 59a may also be different from the length L3 of the vertically extending side of the hollow portion 61 paired with the second cut-and-raised portion 59b.

[0089] Fig. 5(A) is a plan view showing a plurality of louvers 69 in the fins 43 provided in the heat exchanger 27 according to the embodiment of the present invention, Fig. 5(B) is a cross-sectional view taken along line D-D of Fig. 5(A), Fig. 5(C) is a cross-sectional view taken along line E-E of Fig. 5(A), Fig. 5(D) is a view of Fig. 5(A) seen from the back, Fig. 5(E) is a perspective view of Fig. 5(A), and Fig. 5(F) is a perspective view of Fig. 5(D). For ease of explanation, adjacent heat transfer tubes 41 are attached in Fig. 5(A) and removed in Figs. 5(B) to 5(F).

[0090] 5(A) to 5(F), each fin 43 is preferably provided in a region S between adjacent heat transfer tubes 41 by cutting out a portion of the fin 43 and having a plurality of louvers 69 aligned parallel to the insertion direction of the cutouts 53. The plurality of louvers 69 satisfies the following condition:

[0091] Specifically, within region S, the region on the side of terminal end 53b of cutout portion 53, with first virtual line VL1 as the boundary, is referred to as region S1, and the region on the side of open end 53a of cutout portion 53 is referred to as region S2. First virtual line VL1 divides region S into regions S1 and S2. Furthermore, of the multiple louvers 69, each louver 69 provided in region S1 is referred to as a first louver 69a, and each louver 69 provided in region S2 is referred to as a second louver 69b. In this case, each first louver 69a is inclined at an angle θ (°) with respect to the surface of fin 43, and each second louver 69b is inclined at an angle 180-θ (°) with respect to the surface of fin 43.

[0092] Each of the first louvers 69a is provided to cover 50% or more of the area of ​​the region S1, and each of the second louvers 69b is provided to cover 50% or more of the area of ​​the region S2. In the present embodiment, the first louvers 69a are provided on the upwind side and the second louvers 69b are provided on the downwind side with respect to the air flow direction FL of the heat exchanger 27, but the first louvers 69a may be provided on the downwind side and the second louvers 69b may be provided on the upwind side.

[0093] The multiple louvers 69 are cut and raised on both surfaces of the fins 43. The multiple louvers 69 increase the contact area with the airflow passing between adjacent heat transfer tubes 41, thereby increasing the amount of heat exchanged by the fins 43. If the cut-and-raised angles of the multiple louvers 69 were the same in regions S1 and S2, the airflow passing between adjacent heat transfer tubes 41 would be blocked by the first louvers 69a on the upwind side, and the proportion of the airflow that comes into contact with the second louvers 69b on the downwind side would decrease. In other words, the amount of heat exchanged by the second louvers 69b on the downwind side would be lower than that by the first louvers 69a on the upwind side.

[0094] On the other hand, the multiple louvers 69 of the heat exchanger 27 according to this embodiment have different cut-and-raised angles in the regions S1 and S2, causing the airflow passing between adjacent heat transfer tubes 41 to meander near the first imaginary line VL1. After contacting and passing through the first louvers 69a on the windward side, the meandering airflow also comes into contact with the second louvers 69b on the leeward side. Furthermore, the louvers 69 provided in the regions S1 and S2 each occupy a high proportion of the area of ​​the regions S1 and S2, at least 50 percent, so the multiple louvers 69 utilize the region S of the fins 43 to enhance the heat exchange rate.

[0095] In addition, each fin 43 may have a rib 71 extending vertically and provided in the area between the edge 43b of the fin 43 closer to the end 53b of the cutout 53 and the end 53b of the cutout 53.

[0096] The ribs 71 are steps formed by protruding from the surface of the fin 43 in the thickness direction of the fin 43. The ribs 71 are formed continuously from the upper end to the lower end of the fin 43. In this embodiment, the direction in which the ribs 71 protrude from the surface of the fin 43 coincides with the direction in which the circumferential bead 55 protrudes. However, the direction in which the ribs 71 protrude from the surface of the fin 43 does not have to coincide with the direction in which the circumferential bead 55 protrudes.

[0097] Some of the water generated by condensation on the surfaces of the fins 43 and heat transfer tubes 41 flows along the ribs 71. In other words, the ribs 71 collect the water flowing down the surfaces of the fins 43, thereby reducing the amount of water that moves to the upper surfaces of the heat transfer tubes 41 and their vicinity.

[0098] As described above, the heat exchanger 27 according to this embodiment includes multiple circumferential beads 55 that are offset in the thickness direction of each fin 43 and formed along each of the multiple cutouts 53 to conform to the cross-sectional shape of the multiple heat transfer tubes 41. Water generated by condensation on the surfaces of the heat transfer tubes 41 and fins 43 flows vertically downward due to gravity, condensing repeatedly and moving to the upper flat surface 41a of the heat transfer tube 41 and its vicinity. The water that has moved to the upper flat surface 41a of the heat transfer tube 41 and its vicinity flows along the circumferential beads 55 and the circumferential bead connectors 58 connecting the circumferential beads 55 and the flat plate portion 57. The water merges with other flowing water at the flat plate portion 57 and is quickly discharged to the outside of the heat exchanger 27. Therefore, the heat exchanger 27 can prevent water from accumulating around the heat transfer tubes 41. In other words, the heat exchanger 27 achieves excellent drainage performance due to the water collection effect of the circumferential beads 55.

[0099] Furthermore, by including a plurality of fins 43 each having a plurality of circumferential beads 55, the heat exchanger 27 can increase the rigidity around the notches 53 of the fins 43. The increased rigidity around the notches 53 makes the fins 43 less likely to be distorted when the heat transfer tubes 41 are inserted into the notches 53 of the fins 43. This allows the heat exchanger 27 to be more manufacturable.

[0100] In addition, the heat exchanger 27 of this embodiment is equipped with a circumferential bead 55 including a first circumferential bead 55a arranged along the upper longitudinal edge 53d of the cutout portion 53, a second circumferential bead 55b arranged along the lower longitudinal edge 53e of the cutout portion 53, and a curved third circumferential bead 55c that connects the first circumferential bead 55a and the second circumferential bead 55b and is arranged along the terminal edge 53f of the cutout portion 53. Therefore, the heat exchanger 27 causes water to flow around the heat transfer tube 41 along the first circumferential bead 55a, the second circumferential bead 55b, and the third circumferential bead 55c, and also causes water to flow along the circumferential bead connection portion 58 that connects the first circumferential bead 55a, the second circumferential bead 55b, and the third circumferential bead 55c to the flat portion 57, thereby further improving drainage around the heat transfer tube 41.

[0101] The heat exchanger 27 according to the present embodiment also includes a circumferential bead 55 having a circumferential bead flat portion 56 that intersects with the flat surface 41 a of the heat transfer tube 41, with the shortest distance W from the notch 53 to the outer circumferential edge 56 a of the circumferential bead flat portion 56 being set within the range of Relational Formula (1). Therefore, by setting the shortest distance W within the range of Relational Formula (1) based on the relationship between the distance TH between the opposing flat surfaces 41 a of the heat transfer tube 41 and the spacing TP between vertically adjacent notches 53, the heat exchanger 27 can improve the water collection effect of the circumferential bead 55 and obtain even better drainage performance in accordance with the analysis results regarding the drainage performance of the heat exchanger 27.

[0102] Furthermore, the heat exchanger 27 according to this embodiment includes a circumferential bead 55 having an offset H between the flat plate portion 57 and the circumferential bead flat portion 56 that is set within the range of the relational expression (2). If the offset H is 0.1 millimeters or less, below the lower limit of the relational expression (2), the water collection effect of the circumferential bead 55 may be excessively reduced, and water may easily move over the circumferential bead flat portion 56 and into the heat transfer tube 41. On the other hand, if the offset H is equal to or greater than FP / 2, which exceeds the upper limit of the relational expression (2), it may be difficult to form the circumferential bead 55 on the fin 43 without distortion during press processing, depending on the material and thickness of the fin 43. Therefore, by satisfying the relational expression (2), the heat exchanger 27 can exhibit water collection without impairing processability and manufacturability.

[0103] The heat exchanger 27 according to this embodiment also includes at least one cut-and-raised portion 59, including a first cut-and-raised portion 59a, whose position is determined by the positional relationship between three imaginary straight lines, the first to third imaginary lines VL1 to VL3, and one imaginary line segment VLS. The first cut-and-raised portion 59a and a cavity 61 paired with the first cut-and-raised portion 59a are disposed in a specific region below the lower flat surface 41a of the vertically upper heat transfer tube 41 of adjacent heat transfer tubes 41. Due to the absence of surface tension, the cavity 61 blocks water moving toward the lower flat surface 41a of the vertically upper heat transfer tube 41 of adjacent heat transfer tubes 41, preventing water from entering the region S between the adjacent heat transfer tubes 41. In other words, by specifying the position of the first raised portion 59a and the hollow portion 61 that pairs with the first raised portion 59a, the heat exchanger 27 can maintain the spacing FP in the stacking direction of the multiple fins 43, thereby achieving excellent manufacturability, while also blocking water that attempts to move to the upper surface of the heat transfer tube 41 and its vicinity, thereby further improving drainage performance.

[0104] Furthermore, the heat exchanger 27 according to this embodiment satisfies relational expression (3) when D1 is the shortest distance between the outer peripheral edge 56a of the circumferential bead flat portion 56 and the terminal end 53b of the cutout 53, D2 is the shortest horizontal distance between the outer peripheral edge 56a of the circumferential bead flat portion 56 and the windward end 61c of the cavity 61, and D3 is the shortest vertical distance between the edge 43b of the fin 43 closest to the terminal end 53b of the cutout 53 and the terminal end 53b of the cutout 53. Therefore, the heat exchanger 27 can optimize the drainage path in the flat portion 57 by appropriately positioning the first cut-and-raised portions 59a and the circumferential bead 55. In other words, the heat exchanger 27 can further improve drainage performance by combining the circumferential bead 55 and the first cut-and-raised portions 59a.

[0105] Furthermore, the heat exchanger 27 according to this embodiment includes multiple fins 43 each having a cavity 61 that penetrates the thickness of the fin 43 when at least one cut-out portion 59 is cut and raised, the cavity 61 becoming part of the notch 53, and a second cut-out portion 59b provided on at least one of the upper edge 53d and the lower edge 53e. Therefore, the heat exchanger 27 can more reliably maintain the spacing FP between the multiple fins 43 in the stacking direction by using the second cut-out portion 59b in addition to the first cut-out portion 59a. Furthermore, the second cut-out portion 59b is formed in a manner that leaves a portion that would normally be cut off during the process of forming at least one cut-out portion 53 in the fin 43. Therefore, the heat exchanger 27 can maintain the spacing FP without compromising manufacturability during the processing of the second cut-out portion 59b.

[0106] Furthermore, the heat exchanger 27 according to this embodiment satisfies the relational expression (4) when, for at least one cut-and-raised portion 59, the length of the vertically extending side of the support portion 63 is L1, the cut-and-raised length of the connection portion 65 is L2, and the length of the vertically extending side of the hollow portion 61 is L3. Therefore, the heat exchanger 27 has the support portion 63 with a short length L1, and can suppress a decrease in manufacturability caused by a long length L1.

[0107] The heat exchanger 27 according to this embodiment also includes a plurality of fins 43, each of which has a plurality of louvers 69 arranged parallel to the longitudinal direction of the cutout 53, and each of which is formed by cutting and raising a portion of the fin 43 in a region S between adjacent heat transfer tubes 41. The plurality of louvers 69 satisfy the following conditions. Specifically, within the region S, a region on the side of the terminal end 53b of the cutout 53, with the first virtual line VL1 as the boundary, is referred to as region S1, and a region on the side of the open end 53a of the cutout 53 is referred to as region S2. Of the plurality of louvers 69, the louvers 69 provided in the region S1 are referred to as first louvers 69a, and the louvers 69 provided in the region S2 are referred to as second louvers 69b. In this case, each of the first louvers 69a is inclined at an angle θ (°) with respect to the surface of the fin 43, and each of the second louvers 69b is inclined at an angle 180-θ (°) with respect to the surface of the fin 43. Each of the first louvers 69a is provided to occupy 50% or more of the area of ​​the region S1, and each of the second louvers 69b is provided to occupy 50% or more of the area of ​​the region S2. Therefore, the heat exchanger 27 can utilize the region S of the fins 43 to increase the amount of heat exchanged between the airflow and the fins 43.

[0108] Furthermore, the heat exchanger 27 according to this embodiment includes a plurality of fins 43 each having a vertically extending rib 71 that is provided in a region between the end edge 43b of the fin 43 that is located near the end 53b of the notch 53 and the end 53b of the notch 53. Therefore, the heat exchanger 27 can reduce the amount of water that reaches the upper surface of the heat transfer tube 41 and its vicinity by the water collection effect of the rib 71, thereby further improving drainage performance.

[0109] Therefore, the heat exchanger 27 according to this embodiment can achieve a high heat exchange rate by including the heat transfer tubes 41 with a flat cross-sectional shape, while also having excellent drainage properties.

[0110] In this embodiment, the heat exchanger 27 is used as an outdoor heat exchanger, but the present invention is not limited to this. In other embodiments, the heat exchanger 27 may be used as an indoor heat exchanger 13. In addition, in this embodiment, the wind blows from the end 53b side of the cutout portion 53 to the open end 53a side. However, the present invention is not limited to this. The wind may blow from the open end 53a of the cutout portion 53 to the end 53b side.

[0111] 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 spirit of the invention. These embodiments and their modifications are included within the scope and spirit of the invention, and are also included in the scope of the invention and its equivalents as defined in the claims.

[0112] 1...air conditioner, 3...indoor unit, 5...outdoor unit, 11...indoor unit housing, 13...indoor heat exchanger, 15...indoor blower, 21...outdoor unit housing, 23...compressor, 25...four-way valve, 27...heat exchanger (outdoor heat exchanger), 29...expansion device, 31...outdoor blower, 33...refrigerant piping, 41...heat transfer tube, 41a...flat surface, 43...fins, 43a, 43b... Edge, 45, 47...Header, 51...Refrigerant flow passage, 53...Notch, 53a...Open end, 53b...Terminal end, 53c...Heat transfer tube introduction portion, 53d...Upper edge, 53e...Lower edge, 53f...Terminal edge, 55...Pipe circumferential bead, 55a...First pipe circumferential bead, 55b...Second pipe circumferential bead, 55c...Third pipe circumferential bead, 56...Pipe circumferential bead flat portion, 56a...Outer Circumferential edge, 57...flat portion, 58...pipe circumferential bead connection portion, 59...cut-and-raised portion, 59a...first cut-and-raised portion, 59b...second cut-and-raised portion, 61...hollow portion, 61a...uppermost end, 61b...lowermost end, 61c...windward end, 63...support portion, 65...connection portion, 67...fin collar, 69...louver, 69a...first louver, 69b...second louver, 71...rib, D1, D3, W...shortest distance, D2...horizontal shortest distance, FL...air flow direction (arrow), FP...spacing, H...offset amount, P, S, S1, S2...area, TH, TP...distance, VLt...virtual line, VL1...first virtual line, VL2...second virtual line, VL3...third virtual line, VLS...virtual line segment, X...extension direction, θ...angle, θb...rise angle.

Claims

1. A heat exchanger comprising: a plurality of fins arranged at intervals in a thickness direction; and a plurality of heat transfer tubes having a flat cross-sectional shape extending through each of the plurality of fins in the thickness direction and arranged at intervals in a direction perpendicular to the thickness direction, wherein each of the fins has a plurality of cutouts extending in an insertion direction perpendicular to the up-down direction in which the plurality of heat transfer tubes are arranged, and into which at least a portion of the heat transfer tube is inserted, when the direction in which the plurality of heat transfer tubes are arranged is defined as the up-down direction, and a plurality of circumferential beads that are offset in the thickness direction of the fin and follow the cross-sectional shape of the heat transfer tube along each of the plurality of cutouts.

2. A heat exchanger as described in claim 1, wherein the circumferential beads include: a first circumferential bead arranged along an upper longitudinal edge of the cutout; a second circumferential bead arranged along a lower longitudinal edge of the cutout; and a curved third circumferential bead connecting the first and second circumferential bead and arranged along a terminal edge of the cutout.

3. The heat exchanger according to claim 1 or 2, wherein the circumferential bead has a circumferential bead flat portion intersecting with a flat surface of the heat transfer tube, and the following relational expression (1) is satisfied when the shortest distance from the notch to the outer periphery of the circumferential bead flat portion is W (millimeters), the distance between the opposing flat surfaces is TH (millimeters), and the distance between the adjacent notches is TP (millimeters): 0.5 mm<W<(TP-TH)÷3 (1) 4. The heat exchanger according to claim 3, wherein each of the fins has a flat portion that is a portion excluding the plurality of cutouts and the plurality of circumferential beads, and the following relational expression (2) is satisfied when the offset amount between the flat portion and the flat portion of the circumferential bead is H (millimeters) and the interval between the plurality of fins is FP (millimeters): 0.1 millimeters<H<FP÷2 (2) 5. Each of the fins has at least one cut-and-raised portion formed by cutting and raising a portion of the fin and in contact with an adjacent fin, and a hollow portion penetrating the fin in the thickness direction when the at least one cut-and-raised portion is cut and raised, and the at least one cut-and-raised portion has a support portion in contact with the adjacent fin, and a connection portion connecting the support portion to a surface of the fin, and a virtual line passing through the center of the width direction of the heat transfer tube and extending in the vertical direction is defined as a first virtual line VL1, a virtual line passing through the center between adjacent heat transfer tubes and extending parallel to the width direction of the heat transfer tube is defined as a second virtual line VL2, a virtual line passing through the center between the uppermost and lowermost ends of the hollow portion and extending parallel to the width direction of the heat transfer tube is defined as a third virtual line VL3, and a line segment that is a part of the third virtual line VL3 and overlaps with the hollow portion is defined as a virtual line segment VLS.

5. The heat exchanger according to claim 1, wherein the at least one cut-and-raised portion includes the virtual line segment VLS within a divided region between adjacent heat transfer tubes, which is on the terminal side of the cut-out portion with respect to the first virtual line VL1 and on the upper heat transfer tube side with respect to the second virtual line, and the support portion and the connection portion include a first cut-and-raised portion arranged so as to be positioned below the third virtual line VL3.

6. The heat exchanger according to claim 5, wherein the circumferential bead has a circumferential bead flat portion that intersects with the flat surface of the heat transfer tube, and the following relational expression (3) is satisfied when the shortest distance between the outer circumferential edge of the circumferential bead flat portion and the end of the notch is D1, the shortest horizontal distance between the outer circumferential edge of the circumferential bead flat portion and the cavity is D2, and the shortest distance from the edge of the fin that extends in the vertical direction and is located near the end of the notch to the end of the notch is D3. D1<D2<D3 (3) 7. A heat exchanger as described in claim 5 or 6, wherein the hollow portion is a part of the cutout portion, and the at least one cutout portion includes a second cutout portion provided on at least one of an upper edge of the cutout portion in the longitudinal direction and a lower edge of the cutout portion in the longitudinal direction.

8. The heat exchanger according to any one of claims 5 to 7, wherein the following relational expression (4) is satisfied, where L1 is the length of the side of the support portion extending in the vertical direction, L2 is the cut-and-raised length of the connection portion, and L3 is the length of the side of the hollow portion extending in the vertical direction. L1 + L2 < L3 (4) 9. Each of the fins is provided in a region S between the adjacent heat transfer tubes by cutting out a part of the fin, and has a plurality of louvers arranged parallel to the insertion direction of the cutout portion, 9. The heat exchanger according to claim 1, wherein a virtual line passing through the center of the heat transfer tube in the width direction and extending in the vertical direction is defined as a first virtual line VL1, a terminal side region of the cutout of the region S is defined as a region S1 and a region on the open end side of the cutout of the region S2, and each of the louvers provided in the region S1 is defined as a first louver and each of the louvers provided in the region S2 is defined as a second louver, each of the first louvers is inclined at an angle θ (°) with respect to the surface of the fin and each of the second louvers is inclined at an angle 180-θ (°) with respect to the surface of the fin, each of the first louvers is provided in an area of ​​50 percent or more of the region S1, and each of the second louvers is provided in an area of ​​50 percent or more of the region S2.

10. A heat exchanger as claimed in any one of claims 1 to 9, wherein each of the fins has a rib extending in the vertical direction and provided in the region between the end edge of the fin extending in the vertical direction and closer to the end of the cutout and the end of the cutout.

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