air conditioner

Abstract

An air conditioner capable of suppressing poor brazing between a U-shaped tube and a heat transfer tube. [Solution] The air conditioner 100 includes a heat exchanger 1, which includes a plurality of heat transfer tubes 3, a plurality of U-shaped tubes 4 connecting two adjacent heat transfer tubes 3, and a first connecting tube 5 and a second connecting tube 6 connected to the heat transfer tubes 3, and the plurality of third heat transfer tubes 33 include an adjacent tube 33a whose at least a portion is located within a first predetermined range from the central axis of the first heat transfer tube 31 when viewed in the axial direction of the first heat transfer tube 31 and within a second predetermined range from the central axis of the second heat transfer tube 32 when viewed in the axial direction of the second heat transfer tube 32, and the plurality of U-shaped tubes 4 include a first U-shaped tube 41 connected to the adjacent tube 33a and a second U-shaped tube 42 connected to a third heat transfer tube 33 different from the adjacent tube 33a, and the thickness of the first U-shaped tube 41 is thicker than the average thickness of the second U-shaped tubes 42.

Description

[Technical Field]

[0001] The present disclosure relates to an air conditioner. [Background technology]

[0002] Patent Document 1 discloses an air conditioner including a plurality of heat transfer tubes arranged in parallel with a gap therebetween and a plurality of U-shaped tubes connecting two adjacent heat transfer tubes. The heat transfer tubes are connected to connecting tubes, such as an inlet tube for introducing a refrigerant into a heat exchanger and an outlet tube for discharging the refrigerant from the heat exchanger. The connections between the heat transfer tubes and the U-shaped tubes, and between the heat transfer tubes and the connecting tubes, are generally made by brazing, either manually or using an automatic brazing device. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 09-210586 Summary of the Invention [Problem to be solved by the invention]

[0004] When heat transfer tubes or U-tubes are made of aluminum, aluminum has a lower melting point than copper and is close to the melting point of the brazing material. This means that the heat transfer tubes and U-tubes around the brazed portion of the connecting tube may be heated simultaneously during the brazing process, potentially melting the heat transfer tube, U-tube, and brazing material. Excessive heating can also cause the brazing material to penetrate into the heat transfer tube or U-tube, potentially leading to cycle blockages and other problems. This can lead to poor brazing of the U-tube when connecting the connecting tube.

[0005] An object of the present disclosure is to provide an air conditioner that can prevent poor brazing between a U-shaped tube and a heat transfer tube. [Means for solving the problem]

[0006] The air conditioner of the present disclosure comprises: A heat exchanger is provided. the heat exchanger includes a plurality of heat transfer tubes, a plurality of U-shaped tubes connecting two adjacent heat transfer tubes, and a first connecting tube and a second connecting tube connected to the heat transfer tubes; When the heat transfer tube connected to the first connecting tube is a first heat transfer tube, the heat transfer tube connected to the second connecting tube is a second heat transfer tube, and the heat transfer tube connected to the U-shaped tube is a third heat transfer tube, the plurality of third heat transfer tubes include adjacent tubes, at least a portion of which is located within a first predetermined range from the central axis of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and within a second predetermined range from the central axis of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube; the plurality of U-shaped tubes include a first U-shaped tube connected to the adjacent tube and a second U-shaped tube connected to the third heat transfer tube different from the adjacent tube; The wall thickness of the first U-tube is greater than the average wall thickness of the second U-tube. [Brief explanation of the drawings]

[0007] [Figure 1] Schematic diagram showing a heat exchanger of an air conditioner according to a first embodiment. [Figure 2] Schematic diagram showing a heat exchanger of an air conditioner according to a second embodiment. [Figure 3] FIG. 10 is a schematic diagram showing a heat exchanger of an air conditioner according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0008] (First embodiment) First, an air conditioner according to the first embodiment will be described with reference to Fig. 1. Note that in each figure (as well as Figs. 2 and 3), the dimensional ratios in the drawing do not necessarily match the actual dimensional ratios. Fig. 1 is a schematic diagram showing a heat exchanger 1 of an air conditioner 100 according to the first embodiment.

[0009] The air conditioner 100 is used, for example, as a package air conditioner or a multi-air conditioner for buildings. The air conditioner 100 is equipped with an outdoor heat exchanger, an outdoor fan, a compressor, an indoor heat exchanger, an indoor fan, an expansion valve, and a four-way valve, which are connected by refrigerant piping. The heat exchanger 1 described below is the outdoor heat exchanger and / or the indoor heat exchanger.

[0010] As shown in Fig. 1, the heat exchanger 1 includes a plurality of fins 2 arranged side by side at a predetermined interval, and a plurality of heat transfer tubes 3. The fins 2 are formed into plate shapes from aluminum or an aluminum alloy, and multiple fins 2 are stacked at a predetermined interval in the plate thickness direction. The predetermined interval is set appropriately depending on the performance and usage environment of the air conditioner 100, the thickness of the fins 2, and the like. In Fig. 1 (as well as Figs. 2 and 3), the multiple fins 2 are simply drawn together as a single block.

[0011] The heat transfer tubes 3 are formed into a cylindrical shape from aluminum or an aluminum alloy and are arranged side by side at a predetermined interval along the longitudinal direction of the fins 2, penetrating the fins 2 in the stacking direction (thickness direction). The heat transfer tubes 3 each extend in substantially the same direction (vertical direction in FIG. 1). The predetermined interval (arrangement pitch) is the distance between the central axis of a heat transfer tube 3 and the central axis of an adjacent heat transfer tube 3, and is set appropriately depending on the performance and usage environment of the air conditioner 100.

[0012] In this embodiment, the heat transfer tubes 3 are arranged in two rows parallel to the short side of the fins 2, but this is not limiting. For example, the heat transfer tubes 3 may be arranged in only one row, or in three or more rows. In this embodiment, the heat transfer tubes 3 in each row are arranged in a straight line, but this is not limiting.

[0013] The heat transfer tubes 3 in the first row are arranged in parallel so as to be alternately positioned with the heat transfer tubes 3 in the second row in the longitudinal direction of the fins 2. In this embodiment, the arrangement interval between each heat transfer tube 3 and the other heat transfer tubes 3 adjacent thereto is substantially the same. That is, the arrangement interval between the heat transfer tubes 3 in the first row and the other heat transfer tubes 3 adjacent thereto is substantially the same as the arrangement interval between the heat transfer tubes 3 in the first row and the other heat transfer tubes 3 adjacent thereto in the second row. However, without being limited to the above, the arrangement interval between each heat transfer tube 3 and the other heat transfer tubes 3 adjacent thereto may be different.

[0014] It is preferable that the outer diameters of all the heat transfer tubes 3 are substantially the same. It is preferable that the axial lengths of all the heat transfer tubes 3 are substantially the same. The heat transfer tubes 3 have straight portions, and the ends of the straight portions of the heat transfer tubes 3 are located axially outward of the fins 2 located at the ends in the stacking direction (the outermost axial positions). The axial direction of the heat transfer tubes 3 refers to the central axial direction of the heat transfer tubes 3, and in the axial direction of the heat transfer tubes 3, the axial outer side refers to the direction away from the center of the heat transfer tube 3, and the axial inner side refers to the direction opposite to the axial outer side and approaching the center of the heat transfer tube 3. The axial direction of the heat transfer tubes 3 coincides with the stacking direction (plate thickness direction) of the fins 2.

[0015] The heat exchanger 1 includes a plurality of U-shaped tubes 4 connecting two adjacent heat transfer tubes 3, and a first connecting tube 5 and a second connecting tube 6 connected to the heat transfer tubes 3. The U-shaped tubes 4 (also called return pipes or short U-shaped tubes) are formed in a U shape and are connected to the ends of the straight portions of the heat transfer tubes 3. The U-shaped tubes 4 may be composed of only a curved portion, or may be composed of a curved portion and a straight portion. It is preferable that the outer diameters of the U-shaped tubes 4 are substantially the same. It is preferable that the lengths of the U-shaped tubes 4 in the central axis direction are substantially the same.

[0016] The first connecting pipe 5 and the second connecting pipe 6 are each a long U-shaped pipe connecting two distant heat transfer pipes 3, an inlet pipe for introducing the refrigerant into the heat exchanger 1, or an outlet pipe for introducing the refrigerant out of the heat exchanger 1. In this embodiment, the first connecting pipe 5 is an inlet pipe and the second connecting pipe 6 is an outlet pipe, but this is not limited to this. When the first connecting pipe 5 and / or the second connecting pipe 6 are / is a long U-shaped pipe, the length of the long U-shaped pipe in the central axis direction is longer than the length of the U-shaped pipe 4 in the central axis direction.

[0017] The U-shaped tube 4, the first connecting tube 5, and the second connecting tube 6 are preferably made of aluminum or an aluminum alloy (other metals such as copper are also acceptable). In this embodiment, the heat transfer tube 3, the U-shaped tube 4, the first connecting tube 5, and the second connecting tube 6 are each made of the same material, but they may also be made of different materials. The connections between the heat transfer tube 3 and the U-shaped tube 4, and between the heat transfer tube 3 and the connecting tubes 5, 6 are each performed by manual brazing, for example.

[0018] Here, among the multiple heat transfer tubes 3, the heat transfer tube 3 connected to the first connecting tube 5 is referred to as the first heat transfer tube 31, the heat transfer tube 3 connected to the second connecting tube 6 is referred to as the second heat transfer tube 32, and the heat transfer tube 3 connected to the U-shaped tube 4 is referred to as the third heat transfer tube 33.

[0019] The heat exchanger 1 is mainly composed of a hairpin pipe formed by connecting two heat transfer tubes 3, a U-shaped tube 4 connecting the hairpin pipes, and fins 2. In this embodiment, the first heat transfer tube 31 connected to the first connecting tube 5, the second heat transfer tube 32 connected to the second connecting tube 6, and the third heat transfer tube 33 connected to the U-shaped tube 4 do not refer to an entire hairpin pipe, but rather to one heat transfer tube of the hairpin pipe that is connected to the first connecting tube 31, the second connecting tube 32, or the U-shaped tube 4.

[0020] The plurality of third heat transfer tubes 33 includes adjacent tubes 33a, at least a portion of which is located within a first predetermined range from the central axis of the first heat transfer tube 31 when viewed in the axial direction of the first heat transfer tube 31 and within a second predetermined range from the central axis of the second heat transfer tube 32 when viewed in the axial direction of the second heat transfer tube 32. Of the plurality of third heat transfer tubes 33, the third heat transfer tubes 33 other than the adjacent tubes 33a are also referred to as non-adjacent tubes 33b. For example, the first predetermined range is a range that includes at least a portion of the heat transfer tubes 3 adjacent to the first heat transfer tube 31 and does not include any heat transfer tubes 3 not adjacent to the first heat transfer tube 31, and the second predetermined range is a range that includes at least a portion of the heat transfer tubes 3 adjacent to the second heat transfer tube 32 and does not include any heat transfer tubes 3 not adjacent to the second heat transfer tube 32.

[0021] The first predetermined range is, for example, a circle of radius R1 (not shown) centered on the central axis of the first heat transfer tube 31. Radius R1 is preferably 60 mm or less, more preferably 50 mm or less, and even more preferably 45 mm. Radius R1 is also preferably 15 mm or more, more preferably 25 mm or more, and even more preferably 35 mm or more.

[0022] The second predetermined range is, for example, a circle with a radius R2 (not shown) centered on the central axis of the second heat transfer tube 32. The radius R2 is preferably 60 mm or less, more preferably 50 mm or less, and even more preferably 45 mm. The radius R2 is also preferably 15 mm or more, more preferably 25 mm or more, and even more preferably 35 mm or more.

[0023] The first predetermined range may be the same as the second predetermined range, or may be different from the second predetermined range. The first predetermined range and the second predetermined range are set appropriately depending on the outer diameter and arrangement interval of the heat transfer tubes 3, etc.

[0024] In this embodiment, the radius R1 and the radius R2 are each 40 mm, and there are two adjacent pipes 33a, but this is not limited to this. For example, there may be only one adjacent pipe 33a, or there may be three or more adjacent pipes 33a.

[0025] The multiple U-shaped tubes 4 include a first U-shaped tube 41 connected to the adjacent tube 33a and a second U-shaped tube 42 connected to a third heat transfer tube 33 (non-adjacent tube 33b) different from the adjacent tube 33a. At least one end of the first U-shaped tube 41 is connected to the adjacent tube 33a. In this embodiment, one end of the first U-shaped tube 41 (on the connecting tubes 5 and 6 side) is connected to the adjacent tube 33a, and the other end of the first U-shaped tube 41 is connected to the non-adjacent tube 33b, but this is not limited to this. Both ends of the first U-shaped tube 41 may be connected to the adjacent tube 33a.

[0026] The wall thickness of the first U-shaped tube 41 is thicker (larger) than the average wall thickness of the second U-shaped tube 42. With this configuration, the connection portion between the first U-shaped tube 41 and the adjacent tube 33a is susceptible to the effects of heat twice, when the first connecting tube 5 is brazed and when the second connecting tube 6 is brazed. Therefore, by increasing the heat capacity of the first U-shaped tube 41, deformation of the first U-shaped tube 41 due to the heat when the first connecting tube 5 and the second connecting tube 6 are brazed can be suppressed. This suppresses poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0027] The wall thickness of the first U-shaped tube 41 is preferably at least 5% larger than the wall thickness of the second U-shaped tube 42, and more preferably at least 10% larger than the wall thickness of the second U-shaped tube 42. For example, if the wall thickness of the second U-shaped tube 42 is 0.8 mm, the wall thickness of the first U-shaped tube 41 is preferably at least 0.9 mm or at least 1.0 mm. The wall thickness of the first U-shaped tube 41 refers to the wall thickness of the first U-shaped tube 41 alone, and the wall thickness of the second U-shaped tube 42 refers to the wall thickness of the second U-shaped tube 42 alone. The wall thickness of the first U-shaped tube 41 is preferably thicker than the wall thickness of the second U-shaped tube 42.

[0028] The thickness of each of the first connecting pipe 5 and the second connecting pipe 6 is set appropriately depending on the installation environment of the air conditioner 100 and the installation position of each connecting pipe 5, 6. The thickness of each connecting pipe 5, 6 may be substantially the same as the thickness of the first U-shaped pipe 41 or the thickness of the second U-shaped pipe 42, or may be different from these thicknesses.

[0029] The first U-shaped tube 41 is preferably provided with an identification portion 411 for distinguishing it from the second U-shaped tube 42. Such a configuration makes it easy to distinguish between the first U-shaped tube 41 and the second U-shaped tube 42, thereby reducing manufacturing defects.

[0030] The identification portion 411 is, for example, a depression (e.g., a notch) or protrusion provided on the surface of the first U-shaped tube 41, a mark made with ink, etc. In this embodiment, a V-shaped mark is provided as the identification portion 411, but any visible mark such as a symbol or letter may be used.

[0031] The inner diameter of the first U-shaped tube 41 is preferably smaller than the inner diameter of the second U-shaped tube 42. With this configuration, the outer diameter of the first U-shaped tube 41 can be made closer to the outer diameter of the second U-shaped tube 42. This allows the outer diameter of the adjacent tube 33a connected to the first U-shaped tube 41 to be substantially the same as the outer diameter of the other third heat transfer tubes 33 (non-adjacent tubes 33b). As a result, it is not necessary to expand the portion of the adjacent tube 33a connected to the first U-shaped tube 41, and the productivity of the heat exchanger 1 can be improved.

[0032] It is preferable that the outer diameter of the first U-shaped tube 41 is substantially the same as the outer diameter of the second U-shaped tube 42. It is preferable that the length of the central axis of the first U-shaped tube 41 is substantially the same as the length of the central axis of the second U-shaped tube 42. However, without being limited to the above, the outer diameter of the first U-shaped tube 41 may be different from the outer diameter of the second U-shaped tube 42, and the length of the first U-shaped tube 41 may be different from the length of the second U-shaped tube 42.

[0033] (Second embodiment) Next, a second embodiment of the air conditioner 100 of the present disclosure will be described with reference to FIG. 2. The second embodiment can be configured similarly to the first embodiment except for the configuration described below, so commonalities will be omitted and differences will be mainly described. Components already described in the first embodiment will be assigned the same reference numerals and redundant description will be omitted. FIG. 2 is a schematic diagram showing a heat exchanger 1 of an air conditioner 100 according to the second embodiment.

[0034] 2, the axial end of the adjacent tube 33a (the portion where it abuts the first U-shaped tube 41) is located axially outward of the respective ends of the first heat transfer tube 31 and the second heat transfer tube 32 (the respective connections with the connecting tubes 5, 6). With this configuration, by making the end position of the adjacent tube 33a different from the respective end positions of the first heat transfer tube 31 and the second heat transfer tube 32, it is possible to prevent deformation of the first U-shaped tube 41 due to heat generated during brazing of the first connecting tube 5 and the second connecting tube 6. This makes it possible to prevent poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0035] In this embodiment, when viewed radially from the heat transfer tube 3, the end position of the adjacent tube 33a is preferably at least 5 mm axially outward from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32, and more preferably at least 10 mm axially outward from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32.

[0036] The end of the adjacent pipe 33a is located axially outward of the end of the non-adjacent pipe 33b connected to the second U-shaped pipe 42. In the axial direction, the position of the end of the adjacent pipe 33a is substantially the same as the position of the end of the non-adjacent pipe 33b connected to the first U-shaped pipe 41.

[0037] The axial length of the adjacent tube 33a is longer than the axial lengths of the non-adjacent tube 33b connected to the second U-shaped tube 42, the first heat transfer tube 31, and the second heat transfer tube 32. The length of the adjacent tube 33a is substantially the same as the axial length of the non-adjacent tube 33b connected to the first U-shaped tube 41.

[0038] The first U-shaped tube 41 in the second embodiment is not provided with an identification portion 411 as in the first embodiment. The same applies to the first U-shaped tube 41 in a third embodiment described later.

[0039] (Third embodiment) Next, a third embodiment of the air conditioner 100 of the present disclosure will be described with reference to FIG. 3. The third embodiment can be configured similarly to the first embodiment except for the configuration described below, so commonalities will be omitted and differences will be mainly described. Components already described in the first embodiment will be assigned the same reference numerals and duplicated explanations will be omitted. FIG. 3 is a schematic diagram showing a heat exchanger 1 of an air conditioner 100 according to the third embodiment.

[0040] 3, the axial end of the adjacent tube 33a (the portion where it abuts the first U-shaped tube 41) is located axially more inward than the axial ends of the first heat transfer tube 31 and the second heat transfer tube 32 (the connections with the connecting tubes 5 and 6). With this configuration, by making the end position of the adjacent tube 33a different from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32, it is possible to prevent deformation of the first U-shaped tube 41 due to heat generated during brazing of the first connecting tube 5 and the second connecting tube 6. This makes it possible to prevent poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0041] In this embodiment, when viewed radially from the heat transfer tube 3, the end position of the adjacent tube 33a is preferably at least 5 mm axially inward from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32, and more preferably at least 10 mm axially inward from the end positions.

[0042] The end position of the adjacent tube 33a is substantially the same as the end position of the non-adjacent tube 33b in the axial direction. The axial length of the adjacent tube 33a is shorter than the axial lengths of the first heat transfer tube 31 and the second heat transfer tube 32. The length of the adjacent tube 33a is substantially the same as the axial length of the non-adjacent tube 33b.

[0043] (Variation) In the first to third embodiments, the spacing between each heat transfer tube 3 and its adjacent heat transfer tube 3 is substantially the same, but this is not limited to this. For example, the spacing between the first heat transfer tube 31 and its adjacent tube 33a may be wider than the average spacing between the third heat transfer tubes 33, and the spacing between the second heat transfer tube 32 and its adjacent tube 33a may be wider than the average spacing between the third heat transfer tubes 33. With this configuration, by widening the spacing between the first heat transfer tube 31 and its adjacent tube 33a and the spacing between the second heat transfer tube 32 and its adjacent tube 33a from the average spacing, the influence of heat during brazing of the first connecting tube 5 and the second connecting tube 6 is reduced, and deformation of the first U-shaped tube 41 can be suppressed. This suppresses poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0044] The average spacing between the third heat transfer pipes 33 is the average value of the spacing between adjacent third heat transfer pipes 33. From the viewpoint of ensuring the performance of the air conditioner 100, the difference between the spacing between the first heat transfer pipe 31 and the adjacent pipe 33a and the average spacing between the third heat transfer pipes 33 is preferably 5 mm or less. The same applies to the spacing between the second heat transfer pipe 32 and the adjacent pipe 33a.

[0045] In the first to third embodiments, the first heat transfer tube 31 is disposed adjacent to the second heat transfer tube 32, but this is not limiting. For example, the third heat transfer tube 33 may be disposed between the first heat transfer tube 31 and the second heat transfer tube 32. Furthermore, although one first heat transfer tube 31 and one second heat transfer tube 32 are provided, this is not limiting. A plurality of first heat transfer tubes 31 and a plurality of second heat transfer tubes 32 may be provided, and the numbers of first heat transfer tubes 31 and second heat transfer tubes 32 may differ from each other.

[0046] [1] As described above, the air conditioner 100 includes the heat exchanger 1, and the heat exchanger 1 includes a plurality of heat transfer tubes 3, a plurality of U-shaped tubes 4 connecting two adjacent heat transfer tubes 3, and a first connecting tube 5 and a second connecting tube 6 connected to the heat transfer tubes 3. When the heat transfer tube 3 connected to the first connecting tube 5 is defined as the first heat transfer tube 31, the heat transfer tube 3 connected to the second connecting tube 6 is defined as the second heat transfer tube 32, and the heat transfer tube 3 connected to the U-shaped tube 4 is defined as the third heat transfer tube 33, the plurality of third heat transfer tubes 33 include the first heat transfer tube 31, the second heat transfer tube 32, and the third heat transfer tube 33. The tube 31 includes an adjacent tube 33a, at least a portion of which is located within a first predetermined range from the central axis of the first heat transfer tube 31 when viewed in the axial direction, and within a second predetermined range from the central axis of the second heat transfer tube 32 when viewed in the axial direction, and the multiple U-shaped tubes 4 include a first U-shaped tube 41 connected to the adjacent tube 33a and a second U-shaped tube 42 connected to a third heat transfer tube 33 different from the adjacent tube 33a, and the thickness of the first U-shaped tube 41 is thicker than the average thickness of the second U-shaped tubes 42.

[0047] This configuration increases the heat capacity of the first U-shaped tube 41, and prevents the first U-shaped tube 41 from being deformed by the heat generated when brazing the first connecting tube 5 and the second connecting tube 6. This prevents poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0048] [2] In the air conditioner 100 described in [1] above, it is preferable that the first U-shaped pipe 41 is provided with an identification portion 411 for distinguishing it from the second U-shaped pipe .

[0049] According to this configuration, it becomes easy to distinguish between the first U-shaped tube 41 and the second U-shaped tube 42, and manufacturing defects can be reduced.

[0050] [3] In the air conditioner 100 described in the above [1] or [2], it is preferable that the inner diameter of the first U-shaped pipe 41 is smaller than the inner diameter of the second U-shaped pipe .

[0051] With this configuration, the outer diameter of the first U-shaped tube 41 can be made closer to the outer diameter of the second U-shaped tube 42. This allows the outer diameter of the adjacent tube 33a connected to the first U-shaped tube 41 to be substantially the same as the outer diameter of the other third heat transfer tube 33. As a result, it is no longer necessary to expand the portion of the adjacent tube 33a connected to the first U-shaped tube 41, and the productivity of the heat exchanger 1 can be improved.

[0052] [4] In the air conditioner 100 described in any one of the above [1] to [3], the wall thickness of the first U-shaped pipe 41 is preferably thicker than the wall thickness of the second U-shaped pipe .

[0053] [5] The air conditioner 100 includes a heat exchanger 1, the heat exchanger 1 including a plurality of heat transfer tubes 3, a plurality of U-shaped tubes 4 connecting two adjacent heat transfer tubes 3, and a first connecting tube 5 and a second connecting tube 6 connected to the heat transfer tubes 3. When the heat transfer tube 3 connected to the first connecting tube 5 is defined as a first heat transfer tube 31, the heat transfer tube 3 connected to the second connecting tube 6 is defined as a second heat transfer tube 32, and the heat transfer tube 3 connected to the U-shaped tube 4 is defined as a third heat transfer tube 33, the plurality of third heat transfer tubes 33 may include an adjacent tube 33a whose at least a portion is located within a first predetermined range from the central axis of the first heat transfer tube 31 when viewed in the axial direction and within a second predetermined range from the central axis of the second heat transfer tube 32 when viewed in the axial direction, and the end of the adjacent tube 33a in the axial direction is located axially outward of each end of the first heat transfer tube 31 and the second heat transfer tube 32 in the axial direction.

[0054] According to this configuration, by making the end position of the adjacent tube 33a different from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32, it is possible to prevent the first U-shaped tube 41 from being deformed by the heat generated when brazing the first connecting tube 5 and the second connecting tube 6. This makes it possible to prevent poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0055] [6] The air conditioner 100 includes a heat exchanger 1, the heat exchanger 1 including a plurality of heat transfer tubes 3, a plurality of U-shaped tubes 4 connecting two adjacent heat transfer tubes 3, and a first connecting tube 5 and a second connecting tube 6 connected to the heat transfer tubes 3. When the heat transfer tube 3 connected to the first connecting tube 5 is defined as a first heat transfer tube 31, the heat transfer tube 3 connected to the second connecting tube 6 is defined as a second heat transfer tube 32, and the heat transfer tube 3 connected to the U-shaped tube 4 is defined as a third heat transfer tube 33, the plurality of third heat transfer tubes 33 may include an adjacent tube 33a whose at least a portion is located within a first predetermined range from the central axis of the first heat transfer tube 31 when viewed in the axial direction and within a second predetermined range from the central axis of the second heat transfer tube 32 when viewed in the axial direction, and the end of the adjacent tube 33a in the axial direction is located axially inner than each end of the first heat transfer tube 31 and the second heat transfer tube 32 in the axial direction.

[0056] According to this configuration, by making the end position of the adjacent tube 33a different from the end positions of the first heat transfer tube 31 and the second heat transfer tube 32, it is possible to prevent the first U-shaped tube 41 from being deformed by the heat generated when brazing the first connecting tube 5 and the second connecting tube 6. This makes it possible to prevent poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0057] [7] In the air conditioner 100 described in any one of [1] to [6] above, the arrangement distance between the first heat transfer pipe 31 and the adjacent pipe 33a may be wider than the average arrangement distance between the third heat transfer pipes 33, and the arrangement distance between the second heat transfer pipe 32 and the adjacent pipe 33a may be wider than the average arrangement distance between the third heat transfer pipes 33.

[0058] According to this configuration, by widening the spacing between the first heat transfer tube 31 and the adjacent tube 33a and the spacing between the second heat transfer tube 32 and the adjacent tube 33a from the average spacing, it is possible to reduce the influence of heat when brazing the first connecting tube 5 and the second connecting tube 6, and to prevent deformation of the first U-shaped tube 41. This makes it possible to prevent poor brazing between the U-shaped tube 4 (first U-shaped tube 41) and the heat transfer tube 3 (adjacent tube 33a).

[0059] [8] In the air conditioner 100 described in any one of [1] to [7] above, the first predetermined range may be a range that includes at least a portion of the heat transfer tubes 3 adjacent to the first heat transfer tube 31, but does not include any heat transfer tubes 3 that are not adjacent to the first heat transfer tube 31, and the second predetermined range may be a range that includes at least a portion of the heat transfer tubes 3 adjacent to the second heat transfer tube 32, but does not include any heat transfer tubes 3 that are not adjacent to the second heat transfer tube 32.

[0060] The air conditioner is not limited to the configurations of the above-described embodiments, nor is it limited to the above-described effects. Furthermore, it goes without saying that various modifications can be made to the air conditioner without departing from the spirit of the present disclosure. For example, it goes without saying that one or more of the configurations according to the first to third embodiments or the configurations according to the modified examples described above may be arbitrarily selected and employed in the configurations according to other embodiments. [Explanation of symbols]

[0061] 100...Air conditioner 1...Heat exchanger 2. Fin 3...Heat transfer tube 31...First heat transfer tube 32...Second heat transfer tube 33...Third heat transfer tube 33a...adjacent pipe 33b...Non-adjacent pipes 4...U-shaped tube 41...1st U-shaped tube 411...Identification section 42…Second U-shaped tube 5...First connecting pipe 6...Second connecting pipe

Claims

1. A heat exchanger is provided. the heat exchanger includes a plurality of heat transfer tubes, a plurality of short U-shaped tubes connecting two adjacent heat transfer tubes, and a first connecting tube and a second connecting tube connected to the heat transfer tubes, the first connecting pipe and the second connecting pipe are different pipes from the U-shaped short pipe, When the heat transfer tube connected to the first connecting tube is a first heat transfer tube, the heat transfer tube connected to the second connecting tube is a second heat transfer tube, and the heat transfer tube connected to the U-shaped short tube is a third heat transfer tube, the plurality of third heat transfer tubes include adjacent tubes, at least a portion of which is located within a first predetermined range from a central axis of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and within a second predetermined range from the central axis of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube; the plurality of short U-shaped tubes include a first U-shaped tube connected to the adjacent tube and a second U-shaped tube connected to the third heat transfer tube different from the adjacent tube; An air conditioner, wherein the wall thickness of the first U-shaped tube is thicker than the average wall thickness of the second U-shaped tube.

2. The air conditioner according to claim 1 , wherein the first U-shaped tube is provided with an identification portion for distinguishing it from the second U-shaped tube.

3. The air conditioner according to claim 1 , wherein an inner diameter of the first U-shaped pipe is smaller than an inner diameter of the second U-shaped pipe.

4. The air conditioner according to claim 1 , wherein a wall thickness of the first U-shaped tube is greater than a wall thickness of the second U-shaped tube.

5. A heat exchanger is provided. the heat exchanger includes a plurality of heat transfer tubes, a plurality of short U-shaped tubes connecting two adjacent heat transfer tubes, and a first connecting tube and a second connecting tube connected to the heat transfer tubes, the first connecting pipe and the second connecting pipe are different pipes from the U-shaped short pipe, When the heat transfer tube connected to the first connecting tube is a first heat transfer tube, the heat transfer tube connected to the second connecting tube is a second heat transfer tube, and the heat transfer tube connected to the U-shaped short tube is a third heat transfer tube, the plurality of third heat transfer tubes include adjacent tubes, at least a portion of which is located within a first predetermined range from a central axis of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and within a second predetermined range from the central axis of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube; an end of the adjacent tube in the axial direction is located axially outward of each end of the first heat transfer tube and the second heat transfer tube in the axial direction; the plurality of short U-shaped tubes include a first U-shaped tube connected to the adjacent tube and a second U-shaped tube connected to the third heat transfer tube different from the adjacent tube; an axial end of the adjacent tube is positioned axially outward of an axial end of the third heat transfer tube connected to the second U-shaped tube.

6. A heat exchanger is provided. the heat exchanger includes a plurality of heat transfer tubes, a plurality of short U-shaped tubes connecting two adjacent heat transfer tubes, and a first connecting tube and a second connecting tube connected to the heat transfer tubes, the first connecting pipe and the second connecting pipe are different pipes from the U-shaped short pipe, When the heat transfer tube connected to the first connecting tube is a first heat transfer tube, the heat transfer tube connected to the second connecting tube is a second heat transfer tube, and the heat transfer tube connected to the U-shaped short tube is a third heat transfer tube, the plurality of third heat transfer tubes include adjacent tubes, at least a portion of which is located within a first predetermined range from a central axis of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and within a second predetermined range from the central axis of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube; an axial end of the adjacent tube is positioned axially more inward than axial ends of the first heat transfer tube and the second heat transfer tube.

7. an arrangement interval between the first heat transfer tube and the adjacent tube is wider than an average arrangement interval between the third heat transfer tubes; The air conditioner according to any one of claims 1 to 6, wherein the arrangement interval between the second heat transfer tube and the adjacent tube is wider than the average arrangement interval between the third heat transfer tubes.

8. the first predetermined range is a range that includes at least a part of the heat transfer tubes adjacent to the first heat transfer tube, and does not include any of the heat transfer tubes that are not adjacent to the first heat transfer tube, The air conditioner according to any one of claims 1 to 6, wherein the second predetermined range is a range that includes at least a portion of the heat transfer tubes adjacent to the second heat transfer tube, and does not include the heat transfer tubes that are not adjacent to the second heat transfer tube.

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