Heat exchanger, air conditioner, method for manufacturing heat exchanger, method for manufacturing air conditioner, and device for manufacturing heat exchanger

Abstract

This heat exchanger (10) comprises: a header (1) in which a plurality of opening-shaped insertion holes (1a-1) in which the XZ cross-section has a shorter length in a width direction (D2) than the length in a longitudinal direction (D1) are formed at intervals in a second direction; and a plurality of heat transfer pipes (2) which are inserted into the plurality of insertion holes (1a) and through which a fluid flows. The plurality of heat transfer pipes (2) are formed to have a cross-sectional shape having a shorter length in a width direction (D4) than the length in a longitudinal direction (D3). A first heat transfer pipe (2-1) among the plurality of heat transfer pipes (2) is inserted into a first insertion hole (1a-1) among the plurality of insertion holes (1a). The first insertion hole (1a-1) is formed such that the longitudinal direction (D1) thereof is inclined with respect to a longitudinal direction (D3) of the first heat transfer pipe (2-1) when viewed in a pipe axis direction (D10) of the first heat transfer pipe (2-1). The first heat transfer pipe (2-1) is joined to the header 1 by brazing with a part of contact portions (C1, C2) as a starting point.

Description

Heat exchanger, air conditioner, method for manufacturing a heat exchanger, method for manufacturing an air conditioner, and apparatus for manufacturing a heat exchanger

[0001] The present disclosure relates to a heat exchanger, an air conditioner, a method for manufacturing a heat exchanger, a method for manufacturing an air conditioner, and an apparatus for manufacturing a heat exchanger.

[0002] Patent Document 1 discloses a heat exchanger that uses an aluminum and brazing clad material. This heat exchanger includes a header tank and tubes with a flat cross section. The header tank and tubes are joined by inserting the tubes into holes formed in the header tank, placing brazing filler metal at the joint between the two, and then brazing them in a furnace, thereby improving the joining strength between the two.

[0003] Japanese Patent Application Laid-Open No. 2001-129658

[0004] In the heat exchanger described in Patent Document 1, if the tubes do not come into contact with the header tank holes during brazing and no brazing starting point is formed, this can lead to poor joints. Also, when multiple tubes are inserted into the header tank holes in a heat exchanger, variations in the dimensions of the header tank and the tubes, as well as insertion resistance due to friction during insertion, can cause the tubes to not come into contact with the header tank holes during brazing, resulting in poor joints.

[0005] The present disclosure has been made in light of the above-mentioned circumstances, and aims to provide a heat exchanger, an air conditioner, a method for manufacturing a heat exchanger, a method for manufacturing an air conditioner, and an apparatus for manufacturing a heat exchanger that can suppress poor bonding during brazing.

[0006] To achieve the above-mentioned object, a heat exchanger according to the present disclosure includes a header having a plurality of insertion holes formed at intervals in a second direction, each of which has an opening shape whose cross section is shorter in a second direction (a width direction orthogonal to a first direction) than in a first direction (a longitudinal direction), and a plurality of heat transfer tubes inserted into the insertion holes and through which a fluid flows. The heat transfer tubes have cross sections each having a length in a fourth direction (a width direction orthogonal to the third direction) shorter than in a third direction (a longitudinal direction). A first heat transfer tube of the plurality of heat transfer tubes is inserted into a first insertion hole of the plurality of insertion holes. The first insertion hole is formed so that the first direction is inclined with respect to the third direction of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube. The first heat transfer tube is joined to the header by brazing, starting from at least a portion of a contact portion.

[0007] In the heat exchanger according to the present disclosure, the first insertion hole is formed at an angle with respect to the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, thereby making it possible to suppress poor bonding during brazing.

[0008]

[0009] Embodiment 1. A heat exchanger 10 according to embodiment 1 will now be described with reference to the drawings. In addition, in each drawing, the same reference numerals indicate the same or corresponding parts. For ease of understanding, mutually orthogonal XYZ coordinates are set and referenced as appropriate. The Z-axis direction of the XYZ coordinates is the same direction as the longitudinal direction D1 of the elongated hole shape of the insertion hole 1a formed in the header 1, as shown in FIG. 2. The X-axis and Y-axis directions of the XYZ coordinates are directions perpendicular to the longitudinal direction D1.

[0010] The heat exchanger 10 is used in a refrigeration cycle device in which a refrigerant is circulated, such as an air conditioner, etc. As shown in Figures 1 and 2, the heat exchanger 10 includes headers 1 and 4, a plurality of heat transfer tubes 2, a plurality of fins 3, and side plates 5 and 6.

[0011] The header 1 is a hollow cylindrical pipe extending in the X-axis direction. In the first embodiment, the header 1 is formed in a rectangular tubular shape. However, this is not limited thereto. The header 1 may be formed in a shape other than a rectangular tubular shape. For example, the header 1 may be formed in a cylindrical shape. The header 1 is also formed from a material with high thermal conductivity. The header 1 is formed, for example, from a metal, more specifically, from aluminum. However, this is not limited thereto. The header 1 may be formed from a material other than aluminum. For example, a fluid, more specifically, a refrigerant, flows inside the header 1. However, this is not limited thereto. The fluid is not limited to a refrigerant and may be changed as appropriate depending on the application of the heat exchanger 10. Furthermore, an insertion hole 1a is formed in the header 1, as shown in FIGS. 3 and 4 .

[0012] As shown in FIGS. 4, 6A, and 6B, the insertion holes 1a communicate with the fluid flow path inside the header 1. The +Y side ends of the heat transfer tubes 2 are inserted into the insertion holes 1a. In the first embodiment, the header 1 is formed with a plurality of insertion holes 1a, including a first insertion hole 1a-1, a second insertion hole 1a-2, and a third insertion hole 1a-3. Although simplified in the figures, for example, 100 insertion holes 1a are formed. Heat transfer tubes 2 are inserted into all of the plurality of insertion holes 1a. Furthermore, the cross section of the insertion holes 1a is formed in an open shape in which the length in the width direction D2 perpendicular to the longitudinal direction D1 is shorter than the length in the longitudinal direction D1. More specifically, in the present embodiment, the cross section of the insertion holes 1a is formed in an opal shape in which the length in the width direction D6 is shorter than the length in the longitudinal direction D5. More specifically, the first insertion hole 1a-1 of the multiple insertion holes 1a has a cross section whose length in the width direction D2 is shorter than its length in the longitudinal direction D1 and whose center is an ellipse centered at a center point P1. Furthermore, the second insertion hole 1a-2 and the third insertion hole 1a-3 of the multiple insertion holes 1a have cross sections whose length in the width direction D8 perpendicular to the longitudinal direction D7 is shorter than their length in the longitudinal direction D7. Specifically, in this embodiment, the second insertion hole 1a-2 and the third insertion hole 1a-3 have cross sections whose length in the width direction D6 is shorter than their length in the longitudinal direction D5. Furthermore, the second insertion hole 1a-2 and the third insertion hole 1a-3 have cross sections whose length in the width direction D8 is shorter than their length in the longitudinal direction D7 and whose center is an ellipse centered at a center point P1. The ellipse of each of these insertion holes 1a is a circle having a pair of opposing flat surfaces 1c and a pair of opposing curved surfaces 1d. The insertion holes 1a are arranged at equal intervals in the X-axis direction, which is perpendicular to the longitudinal direction. In the present embodiment, the longitudinal directions D1 and D7 are the same as the Z-axis direction, and the width directions D2 and D8 are the same as the X-axis direction.

[0013] In the first embodiment, the first insertion hole 1a-1 of the multiple insertion holes 1a is formed near the center in the X-axis direction of the header 1. Unlike the other insertion holes 1a, the first insertion hole 1a-1 is formed such that the longitudinal direction D1 of the elongated hole shape in its cross section is inclined with respect to the Z-axis direction. The inclination angle of the first insertion hole 1a-1 is, for example, 1°.

[0014] Of the multiple insertion holes 1a, the second insertion hole 1a-2 and the third insertion hole 1a-3 are provided on both sides of the first insertion hole 1a-1 in the width direction D2. The second insertion hole 1a-2 and the third insertion hole 1a-3 are formed so that the longitudinal direction D7 of the elongated hole shape of their cross sections is parallel to the Z-axis direction.

[0015] The header 1 formed as described above has two contact portions C1 and C2 that come into contact with the heat transfer tube 2 in the first insertion hole 1a-1.

[0016] The end of the heat transfer tube 2 on the +Y side is inserted into the insertion hole 1a of the header 1. The heat transfer tube 2 is made of, for example, a material with high thermal conductivity. The heat transfer tube 2 is made of, for example, a metal, more specifically, aluminum. However, this is not a limitation. The heat transfer tube 2 may be made of a material other than aluminum. A fluid, more specifically, a refrigerant, flows through the flow path holes formed inside the heat transfer tube 2. However, this is not a limitation, and the fluid is not limited to a refrigerant and can be changed as appropriate depending on the application of the heat exchanger 10.

[0017] The heat transfer tube 2 has a plurality of holes 2a formed therein, for example, by being separated by a plurality of partition walls 2b. A fluid flows through these holes 2a. However, this is not limited thereto. The heat transfer tube 2 does not necessarily have to have a plurality of holes 2a. For example, the heat transfer tube 2 may have only one hole 2a formed therein by not having a partition wall 2b.

[0018] The heat transfer tubes 2 have an outer shape such that their cross sections are oval in shape, with the length in a width direction D4 perpendicular to the longitudinal direction D3 being shorter than the length in the longitudinal direction D3. More specifically, the heat transfer tubes 2 have a cross section such that the length in the width direction D4 is shorter than the length in the longitudinal direction D3, and the cross section is formed in a flat shape centered on a central point P2. The flat shape of the heat transfer tube 2 has a pair of flat surfaces 2c and a pair of curved surfaces 2d. The plurality of heat transfer tubes 2 are arranged at equal intervals in the X-axis direction. In the first embodiment, the heat exchanger 10 includes a plurality of heat transfer tubes 2, including a first heat transfer tube 2-1, a second heat transfer tube 2-2, and a third heat transfer tube 2-3.

[0019] In the present embodiment 1, the first heat transfer tube 2-1 of the multiple heat transfer tubes 2 is inserted into the first insertion hole 1a-1 located near the center in the X-axis direction of the header 1. The first heat transfer tube 2-1 is formed so that the longitudinal direction D3 of the flattened cross section is parallel to the Z-axis direction.

[0020] Of the multiple heat transfer tubes 2, the second heat transfer tube 2-2 and the third heat transfer tube 2-3 are arranged on either side of the first heat transfer tube 2-1 in the width direction D2. Similar to the first heat transfer tube 2-1, the second heat transfer tube 2-2 and the third heat transfer tube 2-3 are formed so that the longitudinal direction D3 of the flattened cross section is parallel to the Z-axis direction.

[0021] As shown in FIGS. 1 and 2 , the fins 3 are arranged alternately in the X-axis direction with respect to the multiple heat transfer tubes 2. The fins 3 are corrugated fins formed in a wave shape when viewed from the +Z side. The fins 3 are made of, for example, a material with high thermal conductivity. The fins 3 are made of, for example, a metal, more specifically, aluminum or copper. However, this is not limited thereto. The fins 3 may be made of a material other than aluminum or copper. The fins 3 are incorporated into the heat exchanger 10 so as to enhance the heat dissipation effect of the heat exchanger 10 by being arranged alternately with the heat transfer tubes 2. The fins 3 and the multiple heat transfer tubes 2 form a core 9 of the heat exchanger 10.

[0022] The header 4 is a member equivalent to the header 1 and is a hollow cylindrical pipe extending in the X-axis direction. In the first embodiment, the header 4 is formed in a rectangular tubular shape. However, this is not limited thereto. The header 4 may be formed in a shape other than a rectangular tubular shape. For example, the header 4 may be formed in a cylindrical shape. The header 4 is also formed from a material with high thermal conductivity. The header 4 is formed, for example, from a metal, more specifically, from aluminum. However, this is not limited thereto. The header 4 may be formed from a material other than aluminum. For example, a fluid, specifically, a refrigerant, flows inside the header 4. However, this is not limited thereto. The fluid is not limited to a refrigerant and may be changed as appropriate depending on the application of the heat exchanger 10. The header 4 is also formed with an insertion hole 4a, as shown in FIGS. 3 and 5 .

[0023] As shown in FIGS. 5, 6A, and 6B, the insertion holes 4a communicate with the fluid flow path inside the header 4. The -Y side ends of the heat transfer tubes 2 are inserted into the insertion holes 4a. In the first embodiment, the header 4 is formed with a plurality of insertion holes 4a, including a fourth insertion hole 4a-1, a fifth insertion hole 4a-2, and a sixth insertion hole 4a-3. Although the insertion holes 4a are simplified in the figures, for example, 100 insertion holes 4a are formed. Heat transfer tubes 2 are inserted into all of the plurality of insertion holes 4a. Furthermore, the cross section of the insertion holes 4a is formed in an open shape in which the length in the width direction D6 perpendicular to the longitudinal direction D5 is shorter than the length in the longitudinal direction D5. More specifically, in the present embodiment, the cross section of the insertion holes 4a is formed in an opal shape in which the length in the width direction D6 is shorter than the length in the longitudinal direction D5. More specifically, the cross section of the insertion hole 4a is formed in an ellipse with a length in the width direction D6 shorter than a length in the longitudinal direction D5 and a center point P4. The multiple insertion holes 4a are provided at equal intervals in the X-axis direction perpendicular to the longitudinal direction.

[0024] In the first embodiment, the fourth insertion hole 4a-1 of the multiple insertion holes 4a is formed near the center of the header 4 in the X-axis direction. Unlike the other insertion holes 4a, the fourth insertion hole 4a-1 is formed such that the longitudinal direction D5 of the elongated hole in its cross section is inclined with respect to the Z-axis direction. As shown in FIG. 3, the fourth insertion hole 4a-1 is inclined in the same direction as the first insertion hole 1a-1 when viewed in the tube axis direction D10 of the heat transfer tube 2. Specifically, as indicated by arrow Y3 in FIG. 3, the fourth insertion hole 4a-1 is formed such that its upper end is inclined to the right, similar to the first insertion hole 1a-1, when viewed in the +Y direction.

[0025] 5, 6A, and 6B, the fifth insertion hole 4a-2 and the sixth insertion hole 4a-3 of the multiple insertion holes 4a are provided on both sides of the fourth insertion hole 4a-1 in the width direction D6. The fifth insertion hole 4a-2 and the sixth insertion hole 4a-3 are formed so that the longitudinal direction D5 of the elongated hole shape of their cross section is parallel to the Z-axis direction.

[0026] The header 4 formed as described above has two contact portions C3 and C4 that come into contact with the heat transfer tube 2 in the fourth insertion hole 4a-1.

[0027] As shown in Fig. 1 , the side plates 5, 6 cover the core of the heat exchanger 10, which is formed by the heat transfer tubes 2 and the fins 3, from both sides to protect the heat transfer tubes 2 and the fins 3. The side plates 5, 6 are made of, for example, metal, more specifically, aluminum. However, the material is not limited to this. The side plates 5, 6 may also be made of a material other than aluminum.

[0028] A method for manufacturing the heat exchanger 10 formed as above will be described with reference to the drawings.

[0029] First, as shown in Figures 1 to 3, a worker manufacturing a heat exchanger 10 prepares the same number of heat transfer tubes 2 as the number of insertion holes 1a, 4a in the headers 1, 4, and the fins 3 to be provided between the heat transfer tubes 2. The worker arranges the heat transfer tubes 2 and the fins 3 alternately and in parallel. In this way, the core 9 of the heat exchanger 10 formed by the heat transfer tubes 2 and the fins 3 is assembled. Furthermore, side plates 5, 6 are arranged on both side surfaces of the core.

[0030] Next, as shown in FIG. 7A , the worker compresses the core 9 from both sides in the X-axis direction by pressing the side plates 5 and 6 with a pressing portion of an assembly device (not shown). Then, the worker inserts the heat transfer tubes 2 into the insertion holes 1 a and 4 a of the headers 1 and 4. Then, the worker uses restraining devices (not shown) to restrain the core 9 from both sides of the side plates 5 and 6. The restraining device may be, for example, a jig. However, this is not limited to this. The restraining device may be anything other than a jig as long as it restrains the core 9. The restraining device may be, for example, a wire or a heat-resistant band. Furthermore, as shown in FIG. 7B , the worker operates the assembly device to release the compression applied to the core 9.

[0031] Furthermore, the headers 1, 4 and the heat transfer tubes 2 are joined by furnace brazing. Specifically, a brazing filler metal is placed at the location where the heat transfer tubes 2 are to be joined to the headers 1, 4. Then, the worker places the headers 1, 4, the core 9, and the restraining device in a furnace in which the oxygen and moisture contents are controlled. When heated in the furnace, the headers 1, 4, the core 9, and the restraining device thermally expand. The headers 1, 4 and the restraining device have different thermal expansion coefficients. Therefore, as shown in FIGS. 8A and 8B , the difference in displacement due to thermal expansion between the headers 1, 4 and the core 9 restrained by the restraining device becomes large. Therefore, the heat transfer tubes 2 of the core 9 come into contact with a portion of the inner surface of the insertion holes 1a, 4a, as shown in FIG. 3 , and are brazed starting from this contact point and joined to the headers 1, 4. The heat transfer tube 2, which is located in the central portion of the core 9 in the X-axis direction, has a small difference in displacement due to thermal expansion, as shown in Figures 7A, 7B, 8A, and 8B, but has contact parts C1, C2, C3, and C4 (see Figure 5) that come into contact with the heat transfer tube 2, and is therefore brazed starting from the contact parts C1 to C4 and joined to the headers 1 and 4.

[0032] Finally, the header 1, header 4, core, and restraining device are removed from the furnace and allowed to cool slowly. The restraining device is then removed from the header 1, header 4, and core, which have returned to room temperature. As shown in FIG. 9 , the header 1 returns to its original dimensions after returning to room temperature. The header 4, not shown in FIG. 9 , also returns to its original dimensions. However, the core shrinks by more than its original width. The heat transfer tube 2 is then fixed in contact with the insertion holes 1 a and 4 a, as shown in FIG. 3 , and the gaps between the heat transfer tube 2 and the insertion holes 1 a and 4 a are filled with brazing filler. This completes the heat exchanger 10.

[0033] As described above, in the heat exchanger 10 according to the first embodiment, as shown in FIG. 4, the first insertion hole 1a-1 is formed at an angle with respect to the first heat transfer tube 2-1 when viewed in the axial direction of the first heat transfer tube 2-1. Therefore, in the present disclosure, poor bonding during brazing can be suppressed. Also, in the heat exchanger 10 according to the first embodiment, as shown in FIG. 4, the header 1 has contact portions C1 and C2 that contact the first heat transfer tube 2-1 in the first insertion hole 1a-1. The first heat transfer tube 2-1 is joined to the header 1 by brazing, starting from these contact portions C1 and C2. Therefore, in the heat exchanger 10, poor bonding during brazing can be suppressed.

[0034] 5, in the heat exchanger 10 according to the first embodiment, the header 4 has contact portions C3 and C4 that contact the first heat transfer tube 2-1 in the fourth insertion hole 4a-1. The first heat transfer tube 2-1 is joined to the header 4 by brazing, starting from the contact portions C3 and C4. Therefore, in the heat exchanger 10, poor joining during brazing can be suppressed.

[0035] Modification of First Embodiment In the first embodiment, as shown in FIG. 4, the header 1 has, for example, 100 insertion holes 1a formed therein. However, the number of insertion holes 1a formed therein is not limited to this. The header 1 may have 101 or more insertion holes 1a formed therein, or may have 99 or fewer insertion holes 1a formed therein. However, it is preferable that the header 1 has three or more insertion holes 1a formed therein. It is also preferable that the number of insertion holes 1a formed therein is an odd number.

[0036] Similarly, as shown in Figure 5, the header 4 has 101 insertion holes 4a formed therein. However, the number of insertion holes 4a is not limited to this. The header 4 may have 102 or more insertion holes 4a formed therein, or may have 100 or fewer insertion holes 4a formed therein. However, it is preferable that the header 4 has three or more insertion holes 4a formed therein. It is also preferable that the number of insertion holes 4a formed therein is an odd number. It is also preferable that the header 4 has the same number of insertion holes 4a as the number of insertion holes 1a formed in the header 1.

[0037] 3 to 5, in the first embodiment, the fourth insertion hole 4a-1 is formed with its upper end tilted to the right when viewed in the +Y direction, similar to the first insertion hole 1a-1. However, this is not limited to this. The fourth insertion hole 4a-1 may be formed with its upper end tilted to the left when viewed in the +Y direction, opposite to the first insertion hole 1a-1, as indicated by arrows Y1 and Y2 in FIG. 10. The cross sections of the insertion points at both ends of the heat transfer tube 2 are twisted about the Y-axis, making it easier for the heat transfer tube 2 to come into contact with the first insertion hole 1a-1 and the fourth insertion hole 4a-1.

[0038] Second Embodiment The following describes a heat exchanger 10-2 according to a second embodiment, which has a different shape for the inner surface of the insertion hole 1a of the header 1. In addition, in each drawing, the same reference numerals indicate the same or corresponding parts.

[0039] As shown in FIGS. 11A and 11B , an insertion hole 1a is formed in the header 1 of the heat exchanger 10-2. A protrusion 7 is formed on the inner surface of the insertion hole 1a. The protrusion 7 is formed, for example, using a grooved punch in a press die used to form the insertion hole 1a in the header 1. The height L1 of the protrusion 7 is preferably equal to or greater than the clearance L2 between the insertion hole 1a and the heat transfer tube 2. Specifically, the height L1 is preferably equal to or greater than the clearance L2, which is the value obtained by subtracting the tube width L4 of the heat transfer tube 2 in the X-axis direction from the hole width L3 of the insertion hole 1a in the X-axis direction (L1≧L2=L3−L4). In the second embodiment, the protrusion 7 extends toward the depth of the insertion hole 1a, as shown in FIG. 12 . In the second embodiment, two protrusions 7 are formed in the first insertion hole 1a-1. These two protrusions 7 are asymmetrically positioned relative to the center of the insertion hole 1a-1 when viewed in the axial direction of the heat transfer tube 2. As a result, poor bonding during brazing can be suppressed.

[0040] As shown in FIGS. 11A and 11B, in the second embodiment, two protrusions 7 are formed on the inner surface of the insertion hole 1a. However, this is not limited to this. One protrusion 7 may be formed on the inner surface of the insertion hole 1a. Furthermore, as shown in FIG. 13A, three or more protrusions 7 may be formed on the inner surface of the insertion hole 1a. However, if the number of protrusions 7 is too large, the insertion resistance of the heat transfer tube 2 into the insertion hole 1a of the header 1 increases, reducing the assembly efficiency of the heat exchanger 10. Therefore, from the viewpoint of assembly efficiency, it is preferable that the number of protrusions 7 is two, as shown in FIGS. 11A and 11B. Furthermore, in either case, it is preferable that the protrusions 7 are formed asymmetrically with respect to the center of the insertion hole 1a-1 when viewed in the axial direction of the heat transfer tube 2.

[0041] In the second embodiment, the XZ cross section of the protrusion 7 is formed in a semicircular shape with an arc-shaped apex. However, this is not limited to this. The XZ cross section of the protrusion 7 may be formed in a shape other than a semicircular shape. For example, the XZ cross section of the protrusion 7 may be formed in a polygonal shape such as a rectangular shape, a trapezoidal shape, or a triangular shape. However, from the viewpoint of preventing scratches on the outer surface of the heat transfer tube 2 when the heat transfer tube 2 is inserted into the insertion hole 1a of the header 1, it is preferable that the XZ cross section of the protrusion 7 is formed in a semicircular shape with an arc-shaped apex.

[0042] In the second embodiment, the protrusion 7 extends toward the depth of the insertion hole 1 a as shown in Fig. 12. However, this is not limiting. The protrusion 7 does not have to extend toward the depth of the insertion hole 1 a as in a modified example of the second embodiment shown in Fig. 14.

[0043] The positions of the two protrusions 7 may be changed as appropriate. For example, the two protrusions 7 may be formed near the +Z end and the -Z end of the insertion hole 1a in the longitudinal directions D1 and D7, as shown in Fig. 13B. Alternatively, the two protrusions 7 may be formed symmetrically on both sides near the center of the insertion hole 1a in the longitudinal directions D1 and D7, as shown in Fig. 13C.

[0044] Modification of Embodiment 2. In addition, in Embodiment 2, as shown in FIGS. 11A and 11B, the protrusions 7 are formed on the inner surface of the insertion hole 1a of the header 1. However, this is not limited to this. As in the modification of Embodiment 2 shown in FIGS. 15A and 15B, the protrusions 7 may be formed on the outer surface of the heat transfer tube 2. This embodiment also achieves the same effects as those of Embodiment 1. Furthermore, the number of protrusions 7 formed on the outer surface of the heat transfer tube 2 may be one, or three or more. Furthermore, the protrusions 7 are formed asymmetrically with respect to the center of the heat transfer tube 2 when viewed in the axial direction of the heat transfer tube 2. As a result, poor joining during brazing can be suppressed.

[0045] Furthermore, the protrusions 7 may be formed on both the inner surface of the insertion hole 1a of the header 1 and the outer surface of the heat transfer tube 2. In this case, however, it is preferable that the protrusions 7 formed on the inner surface of the insertion hole 1a of the header 1 and the protrusions 7 formed on the outer surface of the heat transfer tube 2 are formed in positions where they do not come into contact with each other.

[0046] Third Embodiment (Reference Example) As in a heat exchanger 10-3 shown in Fig. 16, the center of the cross section of the heat transfer tube 2 may be positioned so that it is offset in the width direction D2 or the X-axis direction from the center of the insertion hole 1a. In this case, for example, as shown in Fig. 16, by offsetting the formation positions of the insertion holes 1a of the header 1 in the X-axis direction with respect to the heat transfer tube 2, all of the heat transfer tubes 2 are brought into contact with the inner surfaces of all of the insertion holes 1a. In this embodiment, poor bonding during brazing can also be suppressed, and as a result, the same effect as in the first embodiment can be obtained.

[0047] Fourth Embodiment (Reference Example). Furthermore, as in a heat exchanger 10-4 shown in FIG. 17 , the end of the first heat transfer tube 2-1 on the +Z side in the longitudinal direction D3 may be inserted into the first insertion hole 1a-1 while contacting the first insertion hole 1a-1. In this case, for example, as shown in FIG. 17 , the formation position of the first insertion hole 1a-1 of the header 1 is shifted in the longitudinal direction D3 or the Z-axis direction relative to the first heat transfer tube 2-1 to achieve contact. This eliminates clearance between the first insertion hole 1a-1 and the first heat transfer tube 2-1. Furthermore, in this embodiment, only the formation position of the first insertion hole 1a-1 is shifted in the longitudinal direction D3 or the Z-axis direction relative to the first heat transfer tube 2-1, but this is not limited thereto. The formation positions of all the insertion holes 1a may be shifted in the longitudinal direction D3 or the Z-axis direction relative to the heat transfer tube 2. This embodiment also suppresses poor bonding during brazing, thereby achieving the same effect as that of the first embodiment. The end of the heat transfer tube 2 on the +Z side in the longitudinal direction D3 may also be inserted into the insertion hole 4a of the header 4 shown in FIG. 5 while being in contact with it.

[0048] Fifth Embodiment (Reference Example). Also, as in the heat exchanger 10-5 shown in FIG. 18 , both the +Z-side end and the −Z-side end of the first heat transfer tube 2-1 in the longitudinal direction D3 may be inserted into the first insertion hole 1a-1 while contacting each other. In this case, for example, as shown in FIG. 18 , the size of the first insertion hole 1a-1 in the longitudinal direction D1 is made smaller than that of the first heat transfer tube 2-1, so that the first heat transfer tube 2-1 contacts the inner surface of the first insertion hole 1a-1. In this embodiment, only the size of the first insertion hole 1a-1 in the longitudinal direction D1 is made smaller than that of the first heat transfer tube 2-1, but this is not limited to this. The sizes of the insertion holes 1a in the longitudinal directions D1 and D7 may also be made smaller for all heat transfer tubes 2. This embodiment also suppresses poor bonding during brazing, resulting in the same effects as those of the first embodiment. The heat transfer tube 2 may have both ends on the +Z side and the −Z side in the longitudinal direction D3 inserted into the insertion hole 4a of the header 4 shown in FIG. 5 while in contact with each other.

[0049] Although the present embodiment has been described above, the present disclosure is not limited to the above embodiment.

[0050] For example, in this embodiment, as shown in Figures 4, 6A, and 6B, the insertion hole 1a of the header 1 has a cross section that is shorter in the width directions D2 and D8 than in the longitudinal directions D1 and D7, and is formed as an ellipse centered at the center point P1. However, this is not limited to this. The insertion hole 1a may have a cross section that is shorter in the width directions D2 and D8 than in the longitudinal directions D1 and D7, and is formed as an ellipse centered at the center point P1. Furthermore, the insertion hole 1a may have a shape other than an ellipse, as long as the width directions D2 and D8 are shorter than the length in the longitudinal directions D1 and D7.

[0051] Similarly, in this embodiment, as shown in Figures 5, 6A, and 6B, the cross section of the insertion hole 4a is formed as an ellipse with its length in the width direction D6 shorter than its length in the longitudinal direction D5 and its center point P4 as a center. However, this is not limited to this. The cross section of the insertion hole 4a may be formed as an ellipse with its length in the width direction D6 shorter than its length in the longitudinal direction D5 and its center point P4 as a center. Furthermore, the insertion hole 4a may be formed as a shape other than an ellipse or an ellipse as long as its length in the width direction D6 is shorter than its length in the longitudinal direction D5.

[0052] In the present embodiment, as shown in Figures 4, 6A, and 6B, the heat transfer tube 2 has a cross section that is shorter in the width direction D4 than in the longitudinal direction D3 and is formed into a flattened shape centered on a central point P2. However, this is not limited to this. The heat transfer tube 2 may have a cross section that is shorter in the width direction D4 than in the longitudinal direction D3 and is formed into an elliptical shape centered on a central point P2. Furthermore, the heat transfer tube 2 may have a shape other than a flattened or elliptical shape as long as the length in the width direction D4 is shorter than the length in the longitudinal direction D3.

[0053] In this embodiment, as shown in FIGS. 4 to 6A and 6B, the first insertion hole 1a-1 is formed so that the longitudinal direction D1 of its elongated cross-sectional shape is inclined with respect to the Z-axis direction. The first heat transfer tube 2-1 is formed so that the longitudinal direction D3 of its flat cross-sectional shape is parallel to the Z-axis direction. However, this is not limited to this. As shown in FIG. 19, the first insertion hole 1a-1 may be formed so that the longitudinal direction D1 of its elongated cross-sectional shape is parallel to the Z-axis direction, and the first heat transfer tube 2-1 may be formed so that the longitudinal direction D3 of its flat cross-sectional shape is inclined with respect to the Z-axis direction. Even in this example, the first insertion hole 1a-1 can be formed so that it is inclined with respect to the first heat transfer tube 2-1 when viewed in the axial direction of the first heat transfer tube 2-1, thereby suppressing poor joining during brazing.

[0054] Furthermore, the first insertion hole 1a-1 may be formed so that the longitudinal direction D1 of the elongated hole shape of its cross section is inclined in the Z-axis direction, and the first heat transfer tube 2-1 may also be formed so that the longitudinal direction D3 of the flattened shape of its cross section is inclined with respect to the Z-axis direction.

[0055] 11A and 11B, the protrusion 7 is formed only in the first insertion hole 1a-1 of the multiple insertion holes 1a. However, this is not limited to this. The protrusion 7 may also be formed in the insertion holes 1a other than the first insertion hole 1a-1.

[0056] 15A and 15B, in a modification of the second embodiment, the protrusions 7 are formed only on the first heat transfer tube 2-1 among the plurality of heat transfer tubes 2. However, this is not limiting. The protrusions 7 may also be formed on heat transfer tubes 2 other than the first heat transfer tube 2-1.

[0057] 16 to 18, in the third to fifth embodiments, the protrusions 7 are not formed on either the inner surface of the insertion hole 1a or the outer surface of the heat transfer tube 2. However, this is not limited to this. In the third to fifth embodiments, the protrusions 7 may be formed on at least one of the inner surface of the insertion hole 1a and the outer surface of the heat transfer tube 2.

[0058] Furthermore, in the first embodiment, as shown in FIG. 4, the first insertion hole 1a-1 differs from the other insertion holes 1a in that the longitudinal direction D1 of the elongated cross-section of the first insertion hole 1a-1 is inclined with respect to the Z-axis direction. However, this is not limited to this. For example, as shown in FIG. 20, the insertion holes 1a other than the first insertion hole 1a-1 may also have the longitudinal directions D1, D7 of the elongated cross-section of the first insertion hole 1a-1 inclined with respect to the Z-axis direction. For example, it is preferable that the three insertion holes 1a-1, 1a-2, and 1a-3 located near the center of the header 1 in the X-axis direction have the longitudinal directions D1, D7 of the elongated cross-section of the first insertion hole 1a-1 inclined with respect to the Z-axis direction.

[0059] In the example shown in FIG. 20 , the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 located near the center of the header 1 in the X-axis direction are formed such that the longitudinal directions D1 and D7 of the elongated cross-sections thereof are inclined at the same inclination angle relative to the Z-axis direction. However, this is not limited to this. As shown in FIG. 21 , the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 may be formed such that the longitudinal directions D1 and D7 of the elongated cross-sections thereof are inclined at different inclination angles relative to the Z-axis direction. Specifically, as shown in FIG. 21 , the inclination angle of the first insertion hole 1a-1 may be larger than the inclination angles of the second insertion hole 1a-2 and the third insertion hole 1a-3, and the second insertion hole 1a-2 and the third insertion hole 1a-3 may be formed such that they are inclined at the same inclination angle. More specifically, the first insertion hole 1a-1 has a cross section whose length in the width direction D2 is shorter than its length in the longitudinal direction D1 and is formed as an ellipse centered on a center point P1. The second insertion hole 1a-2 has a cross section whose length in the width direction D8 is shorter than its length in the longitudinal direction D7 and is formed as an ellipse centered on a center point P1. Similarly, the third insertion hole 1a-3 has a cross section whose length in the width direction D8 is shorter than its length in the longitudinal direction D7 and is formed as an ellipse centered on a center point P1. In the example shown in FIG. 21 , the seventh direction, which is the longitudinal direction D7 of the second insertion hole 1a-2 and the third insertion hole 1a-3, is inclined with respect to the first direction, which is the longitudinal direction D1 of the first insertion hole 1a-1.

[0060] In the example shown in FIG. 20, the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3, which are located near the center of the header 1 in the X-axis direction, are all formed with their upper ends tilted to the right when viewed in the +Y direction. However, this is not limited to this. For example, as shown in FIG. 22, the tilt directions of the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 may be different. For example, as shown in FIG. 22, the first insertion hole 1a-1 may be formed with its upper end tilted to the right when viewed in the +Y direction, and the second insertion hole 1a-2 and the third insertion hole 1a-3 may be formed with their upper ends tilted to the left.

[0061] In addition, in the first embodiment, the insertion hole 1a is formed so that its cross section has an elongated hole shape. However, this is not limited to this. As shown in FIG. 23 , the insertion hole 1a may be formed so that its cross section has a combination of an elongated hole whose longitudinal direction is in the Z-axis direction and an elongated hole whose longitudinal direction is inclined with respect to the Z-axis direction. The insertion hole 1a may be formed in an oval shape in which the width direction is shorter than the length in the longitudinal direction. The same applies to the insertion hole 4a of the header 4.

[0062] As shown in FIG. 20, the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3, which are located near the center of the header 1 in the X-axis direction, are formed so that the longitudinal directions D1 and D7 of the elongated cross-sectional shapes are inclined with respect to the Z-axis direction. In this case, as shown in FIG. 24, the height L10 of the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 in the Z-axis direction is smaller than the height L11 of the other insertion holes 1a in the Z-axis direction by the amount of inclination (L10<L11). In this case, the center point P1 of the insertion hole 1a is located on a straight line parallel to the X-axis direction. Furthermore, the center points P1 of the insertion holes 1a may be located at equal intervals along the X-axis direction.

[0063] 25, the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 may be formed so that their height L10 in the Z-axis direction is the same as the height L11 in the Z-axis direction of the other insertion holes 1a (L10 = L11). In this case, the cross-sectional areas of the first insertion hole 1a-1, the second insertion hole 1a-2, and the third insertion hole 1a-3 are larger than the cross-sectional areas of the other insertion holes 1a. In this case, the center point P1 of the insertion hole 1a is located on a straight line parallel to the X-axis direction. The center points P1 of the insertion holes 1a may also be located at equal intervals along the X-axis direction.

[0064] As shown in FIG. 26 , the protrusion 7 is preferably formed closer to the end E1 than the center line S2 between the center line S1 of the insertion hole 1a in the Z-axis direction and the end E1 on the +Z side of the insertion hole 1a. Alternatively, the protrusion 7 is preferably formed closer to the end E2 than the center line S3 between the center line S1 and the end E2 on the -Z side. This prevents the heat transfer tube from being pinched between the two protrusions 7 in the width direction, which can lead to crushing, compared to when two protrusions 7 are formed near the center line S1. Furthermore, when two protrusions 7 are formed, it is preferable that the two protrusions 7 are positioned diagonally opposite each other. In other words, it is preferable that the two protrusions 7 are formed point-symmetrically about the center point P1 of the insertion hole 1a. This reduces the insertion resistance of the electric heating tube inserted into the insertion hole 1a.

[0065] As shown in FIG. 27, flat surfaces may be formed near the ends E1, E2 on the +Z side and the −Z side of the elongated hole of the insertion hole 1a.

[0066] Furthermore, in the header 1 according to this embodiment, the multiple insertion holes 1a are formed at equal intervals in the X-axis direction, as shown in Fig. 4. However, this is not limited to this. As shown in Fig. 28, the multiple insertion holes 1a may be formed at different intervals in the X-axis direction. The same applies to the multiple insertion holes 4a of the header 4.

[0067] Furthermore, the insertion hole 1a of the header 1 as in this embodiment is generally formed by press working. Therefore, as shown in FIG. 29 , when the insertion hole 1a of the header 1 is formed by press working, it is possible to leave a protrusion 1e protruding from the inner surface of the insertion hole 1a of the header 1. This protrusion 1e is, for example, a burr generated during press working. The protrusion 1e formed on the insertion hole 1a becomes a contact portion with the heat transfer tube 2, thereby improving the stable joining strength during brazing. Furthermore, the protrusion 1e interferes with the heat transfer tube 2, making it possible to prevent the heat transfer tube 2 from coming off the header 1.

[0068] 11A and 11B , when a heat transfer tube 2 is inserted into a header 1 having two protrusions 7 formed on the inner surface of the insertion hole 1a, the surface of the heat transfer tube 2 comes into contact with the protrusions 7. Therefore, as shown in FIG. 30 , a linear depression 11 is formed on the surface of the heat transfer tube 2. The inner surface of the header 1 has a flat second flat surface. The outer surface of the heat transfer tube 2 has a flat first flat surface opposite the second flat surface. If this depression 11 is formed on the first flat surface, the heat transfer tube 2 may come off the header 1 during the process of inserting the heat transfer tube 2 into the header 1 and brazing it. This may result in insufficient brazing bonding strength in the heat exchanger 10. Furthermore, friction occurs between the heat transfer tube 2 and the protrusions 7 of the insertion hole 1a during insertion, which raises concerns about the increased load required to insert the heat transfer tube 2. A method for inserting the heat transfer tubes 2 into the header 1 without forming the linear depressions 11 will be described below with reference to FIG.

[0069] 31A , the heat transfer tube 2 is inserted into the header 1 to a predetermined insertion distance while tilting it in the rotation direction R1 to avoid contact with the protrusions 7. This allows the heat transfer tube 2 to be inserted into the header 1 while avoiding contact between the surface of the heat transfer tube 2 and the protrusions 7.

[0070] 31B , the heat transfer tube 2 is rotated in the rotation direction R2. As a result, a contact portion C5 is formed between the heat transfer tube 2 and the protrusion 7. By inserting the heat transfer tube 2 and then rotating it in the rotation direction R2, no linear depression 11 is formed on the surface of the heat transfer tube 2.

[0071] In this case, as shown in Figure 32, point-like dents 12 are formed on the surface of the heat transfer tube 2 only at positions that come into contact with the protrusions 7. The protrusions 7 fit into the point-like dents 12, making it difficult for the heat transfer tube 2 to come off the header 1. As a result, it is possible to prevent a decrease in the joining strength due to brazing. Furthermore, with this method, friction between the heat transfer tube 2 and the protrusions 7 is less likely to occur when the heat transfer tube 2 is inserted, so the load when inserting the heat transfer tube 2 into the header 1 can be reduced.

[0072] A method for manufacturing a heat exchanger 10 having heat transfer tubes 2 on which point-like depressions 12 are formed will be described below with reference to FIGS. 33A to 33C.

[0073] As shown in Figure 33A, before being inserted into the header 1, the heat transfer tubes 2 and the fins 3 are arranged alternately to form a core 9. In the core 9, the heat transfer tubes 2 and the fins 3 are arranged alternately in a parallel direction. As a result, the core 9 is formed in a plate shape with its thickness direction in the Z-axis direction. The thickness direction of the core 9 is the same as the longitudinal direction D3 of the heat transfer tubes 2. The heat transfer tubes 2 are arranged without any inclination.

[0074] Next, as shown in FIG. 33B , the inclination adjustment jig 21 is fitted into the core 9 from the +Z side. As shown in FIG. 34C , the inclination adjustment jig 21 has multiple gaps 21a formed at intervals with respect to the width direction D2 of the heat transfer tube 2. The multiple gaps 21a are shaped to allow the heat transfer tube 2 to fit therein. A heat transfer tube holding component 22 is fitted into the inclination adjustment jig 21. The heat transfer tube holding component 22 fitted into the inclination adjustment jig 21 forms an inclination within the gap 21a that inclines the longitudinal direction D3 of the heat transfer tube 2. As shown in FIGS. 33B and 34 , by holding the heat transfer tube 2 with the inclination adjustment jig 21 and the heat transfer tube holding component 22, the longitudinal direction D3 of the heat transfer tube 2 is slightly inclined with respect to the plate thickness direction (Z-axis direction) of the plate-shaped core 9.

[0075] When the heat transfer tube 2 is inserted into the insertion hole 1a of the header 1 in this state, the heat transfer tube 2 is inserted into the insertion hole 1a of the header 1 while avoiding contact with the protrusions 7 formed on the inner surface of the insertion hole 1a symmetrically about the center of the hole. At this time, a gap 13 is generated between the protrusions 7 and the heat transfer tube 2, which suppresses friction between the protrusions 7 and the heat transfer tube 2 and makes it possible to suppress an increase in the insertion load.

[0076] 33C , when the heat transfer tube 2 is completely inserted to the predetermined position and the heat transfer tube holder 22 is removed, the heat transfer tube 2 attempts to return from its slightly tilted state to a straight state. At this time, the protrusions 7 between the heat transfer tube 2 and the insertion hole 1a form contact portions C6, forming point-like depressions 12. Since the protrusions 7 are pressed against the point-like depressions 12, deviation of the heat transfer tube 2 in the tube axis direction D10 can be suppressed. Furthermore, since a contact point is provided between the heat transfer tube 2 and the header 1, a starting point for brazing can be formed.

[0077] 31B and 32, point-like dents 12 are formed on the surface of the heat transfer tube 2 only at positions that come into contact with the protrusions 7. The protrusions 7 fit into the point-like dents 12, making it possible to prevent the heat transfer tube 2 from shifting in the tube axis direction D10. Furthermore, the heat transfer tube 2 is brazed to the header 1 starting from the contact portion C6. When protrusions are formed on the heat transfer tube, the dents 11 and 12 are formed on the inner surface of the insertion hole of the header.

[0078] Various aspects of the present disclosure are described below. (Supplementary Note 1) (Supplementary Note 1-1) A heat exchanger comprising: a first header having a first insertion hole formed therein that has an oval cross section, the length of which in a second direction, i.e., a width direction perpendicular to a first direction, is shorter than the length of the first direction, i.e., a longitudinal direction; and a first heat transfer tube that is inserted into the first insertion hole and through which a fluid flows, wherein the first header has at least one contact portion in the first insertion hole that contacts the first heat transfer tube, and the first heat transfer tube is joined to the first header by brazing, starting from at least a part of the contact portion.

[0079] (Supplementary Note 1-2) The heat exchanger according to Supplementary Note 1-1, wherein the first header is formed with a second insertion hole and a third insertion hole provided on both sides of the first insertion hole in the second direction, and the heat exchanger comprises: a second heat transfer tube inserted into the second insertion hole and through which a fluid flows; and a third heat transfer tube inserted into the third insertion hole and through which a fluid flows, and the header has at least one contact portion that contacts the first heat transfer tube in at least the first insertion hole among the first insertion hole, the second insertion hole, and the third insertion hole.

[0080] (Appendix 1-3) The heat exchanger according to Appendix 1-1, wherein the first heat transfer tube has an oval cross section in which the length in a fourth direction, which is the width direction perpendicular to the third direction, is shorter than the length in a third direction, which is the longitudinal direction, and is formed so as to be insertable into the first insertion hole.

[0081] (Supplementary Note 1-4) The heat exchanger according to Supplementary Note 1-3, wherein the first insertion hole has a cross section formed into an oval or ellipse with the center of the hole at the center in the first direction and the center in the second direction, and the first heat transfer tube has a cross section formed into an oval or ellipse with the center of the circle at the center in the third direction and the center in the fourth direction.

[0082] (Supplementary Note 1-5) The heat exchanger according to Supplementary Note 1-4, wherein the center of a cross section of the first heat transfer tube is disposed at a position shifted in the second direction of the first insertion hole with respect to the center of the first insertion hole.

[0083] (Supplementary Note 1-6) The heat exchanger according to Supplementary Note 1-3, wherein one end of the first heat transfer tube in the third direction is inserted into the first insertion hole while contacting the first insertion hole.

[0084] (Supplementary Note 1-7) The heat exchanger according to Supplementary Note 1-6, wherein the other end of the first heat transfer tube opposite to the one end in the third direction is inserted into the first insertion hole while being in contact with the first insertion hole.

[0085] (Supplementary Note 1-8) The heat exchanger according to Supplementary Note 1-3, wherein the first heat transfer tube is inserted into the first insertion hole such that the first direction of a cross section of the first heat transfer tube is inclined with respect to the third direction of a cross section of the first insertion hole.

[0086] (Appendix 1-9) The heat exchanger according to any one of Appendices 1-1 to 1-8, wherein a protrusion is formed on at least one of an inner surface of the first insertion hole and the first heat transfer tube.

[0087] (Appendix 1-10) A heat exchanger according to any one of Appendices 1-2 to 1-9, comprising a second header having a fourth insertion hole formed therein, the fourth insertion hole having an oval cross section whose length in a sixth direction, which is a width direction perpendicular to the fifth direction, is shorter than its length in a fifth direction, which is a longitudinal direction; the first heat transfer tube is inserted into the fourth insertion hole; the second header has at least one contact portion in the fourth insertion hole that contacts the first heat transfer tube; and the first heat transfer tube is joined to the second header by brazing, starting from at least a part of the contact portion.

[0088] (Appendix 1-11) The heat exchanger according to appendix 1-10, wherein the first insertion hole of the first header is formed such that the second direction is inclined with respect to a straight line passing through the center of the first insertion hole and the center of the second insertion hole when viewed in the tube axis direction of the first heat transfer tube, and the fourth insertion hole of the second header is formed such that the sixth direction is inclined at the same inclination angle as the first insertion hole with respect to a straight line passing through the center of the third insertion hole and the center of the fourth insertion hole when viewed in the same tube axis direction.

[0089] (Appendix 1-12) The heat exchanger according to appendix 1-10, wherein the first insertion hole of the first header is formed such that the second direction is inclined with respect to a straight line passing through the center of the first insertion hole and the center of the second insertion hole when viewed in the tube axis direction of the first heat transfer tube, and the fourth insertion hole of the second header is formed such that the sixth direction is inclined on the opposite side to the inclination of the first insertion hole when viewed in the same tube axis direction and a straight line passing through the center of the third insertion hole and the center of the fourth insertion hole.

[0090] (Appendix 1-13) A heat exchanger according to any one of Appendices 1-1 to 1-12, wherein the first header has a second insertion hole formed on one of both sides of the first insertion hole in the second direction, the second insertion hole has an oval cross section whose length in an eighth direction, which is the width direction perpendicular to the seventh direction, is shorter than its length in a seventh direction, which is the longitudinal direction, and the first direction, which is the longitudinal direction of the first insertion hole, is inclined with respect to the seventh direction, which is the longitudinal direction of the second insertion hole.

[0091] (Supplementary Note 2) (Supplementary Note 2-1) A heat exchanger comprising: a first header, in which a plurality of insertion holes, each having an open cross section whose length in a second direction, which is a width direction orthogonal to a first direction, is shorter than its length in a first direction, which is a longitudinal direction, are formed at intervals in the second direction; and a plurality of heat transfer tubes, which are inserted into the plurality of insertion holes and through which a fluid flows, wherein the plurality of heat transfer tubes are formed so that their cross sections have a length in a fourth direction, which is a width direction orthogonal to the third direction, which is a longitudinal direction, shorter than their length in a third direction, which is a longitudinal direction, a first heat transfer tube of the plurality of heat transfer tubes is inserted into a first insertion hole of the plurality of insertion holes, the first direction of the first insertion hole is formed so that the first direction is inclined with respect to the third direction of the first heat transfer tube, when viewed in the tube axial direction of the first heat transfer tube, and the first heat transfer tube is joined to the first header by brazing.

[0092] (Appendix 2-2) A heat exchanger according to appendix 2-1, wherein the heat transfer tubes are inserted into all of the insertion holes, all of the insertion holes are formed such that the first direction is inclined with respect to the third direction of each of the heat transfer tubes inserted into the insertion holes when viewed in the tube axial direction of the first heat transfer tube, and all of the heat transfer tubes are joined to all of the insertion holes by brazing.

[0093] (Appendix 2-3) The heat exchanger according to Appendix 2-1, wherein a second heat transfer tube of the plurality of heat transfer tubes is inserted into a second insertion hole of the plurality of insertion holes, the second insertion hole is formed such that the first direction is parallel to the third direction of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube, and the second heat transfer tube is joined to the first header by brazing.

[0094] (Supplementary Note 2-4) The heat exchanger according to Supplementary Note 2-3, wherein a third heat transfer tube of the plurality of heat transfer tubes is inserted into a third insertion hole of the plurality of insertion holes, the first insertion hole is formed between the second insertion hole and the third insertion hole, the third insertion hole is formed such that the first direction is inclined with respect to the third direction of the third heat transfer tube or is formed parallel to the third direction when viewed in the tube axial direction of the third heat transfer tube, and the third heat transfer tube is joined to the first header by brazing.

[0095] (Supplementary Note 2-5) A heat exchanger comprising: a first header in which a plurality of insertion holes, each having an opening shape in cross section such that a length in a second direction, which is a width direction orthogonal to a first direction, is shorter than a length in a first direction, which is a longitudinal direction, are formed at intervals in the second direction; and a plurality of heat transfer tubes that are inserted into the plurality of insertion holes and through which a fluid flows, wherein a first heat transfer tube of the plurality of heat transfer tubes is inserted into a first insertion hole of the plurality of insertion holes, one protrusion or a plurality of protrusions is formed on an inner surface of the first insertion hole or an outer surface of the first heat transfer tube, and the one protrusion or the plurality of protrusions is formed asymmetrically with respect to a center of the first insertion hole or a center of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and the first heat transfer tube is joined to the first header by brazing.

[0096] (Appendix 2-6) A heat exchanger according to appendix 2-5, wherein the heat transfer tubes are inserted into all of the insertion holes, one protrusion or multiple protrusions are formed on the inner surfaces of all of the insertion holes or on the outer surfaces of all of the heat transfer tubes, the one protrusion or the multiple protrusions are formed asymmetrically with respect to the centers of the insertion holes or the centers of the heat transfer tubes when viewed in the axial direction of each of the heat transfer tubes, and the heat transfer tubes are joined to the first header by brazing.

[0097] (Appendix 2-7) The heat exchanger according to Appendix 2-5, wherein a second heat transfer tube of the plurality of heat transfer tubes is inserted into a second insertion hole of the plurality of insertion holes, one protrusion or multiple protrusions are formed on an inner surface of the second insertion hole or an outer surface of the second heat transfer tube, the one protrusion or the multiple protrusions are formed asymmetrically with respect to the center of the second insertion hole or the center of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube, and the second heat transfer tube is joined to the first header by brazing.

[0098] (Appendix 2-8) The heat exchanger according to Appendix 2-7, wherein a third heat transfer tube of the plurality of heat transfer tubes is inserted into a third insertion hole of the plurality of insertion holes, the first insertion hole is formed between the second insertion hole and the third insertion hole, one protrusion or multiple protrusions are formed on an inner surface of the third insertion hole or an outer surface of the third heat transfer tube, the one protrusion or the multiple protrusions are formed asymmetrically with respect to the center of the third insertion hole or the center of the third heat transfer tube when viewed in the axial direction of the third heat transfer tube, and the third heat transfer tube is joined to the first header by brazing.

[0099] (Supplementary Note 2-9) The heat exchanger according to any one of Supplementary Notes 2-1 to 2-8, wherein a protrusion protruding from an inner surface of the hole is formed at an end of the first insertion hole.

[0100] (Appendix 2-10) A heat exchanger according to any one of Appendices 2-5 to 2-8, wherein an outer surface of the first heat transfer tube has a flat first flat surface, an inner surface of the first insertion hole has a flat second flat surface opposite to the first flat surface, and a recess is formed in the first flat surface or the second flat surface at a formation position where the one protrusion or the multiple protrusions contact.

[0101] (Appendix 2-11) The heat exchanger according to any one of Appendices 2-1 to 2-4, comprising: a second header having a plurality of insertion holes formed at intervals in the sixth direction, each of which has an opening shape in cross section such that the length in a sixth direction, which is a width direction perpendicular to the fifth direction, is shorter than the length in a fifth direction, which is a longitudinal direction; a fourth insertion hole of the plurality of insertion holes of the second header into which a first heat transfer tube of the plurality of heat transfer tubes is inserted; the fourth insertion hole is formed such that the fifth direction is inclined with respect to the third direction of the first heat transfer tube when viewed in the tube axial direction of the first heat transfer tube; and the fourth heat transfer tube is joined to the first header by brazing.

[0102] (Supplementary Note 2-12) The heat exchanger according to Supplementary Note 2-11, wherein the fourth insertion hole is inclined to the same side as the inclination of the first insertion hole when viewed in the same tube axis direction.

[0103] (Supplementary Note 2-13) The heat exchanger according to Supplementary Note 2-11, wherein the fourth insertion hole is inclined in a direction opposite to the inclination of the first insertion hole when viewed in the same tube axis direction.

[0104] (Supplementary Note 2-14) An air conditioner comprising the heat exchanger according to any one of Supplementary Notes 2-1 to 2-13, and adjusting the temperature of an object to be air-conditioned.

[0105] (Appendix 2-15) A method for manufacturing a heat exchanger according to any one of Appendices 2-1 to 2-4, comprising: an assembly process for assembling the heat transfer tubes to the first header by inserting the heat transfer tubes into the insertion holes; and a joining process for brazing and joining the heat transfer tubes to the first header, wherein the joining process includes brazing a first heat transfer tube of the plurality of heat transfer tubes to a first insertion hole of the plurality of insertion holes while tilting the first heat transfer tube relative to the first insertion hole.

[0106] (Appendix 2-16) A method for manufacturing a heat exchanger according to any one of Appendices 2-5 to 2-8, comprising: an assembling step of assembling the plurality of heat transfer tubes to the first header by inserting the plurality of heat transfer tubes into the plurality of insertion holes; and a joining step of brazing and joining the plurality of heat transfer tubes to the first header, wherein the assembling step includes: inserting a first heat transfer tube of the plurality of heat transfer tubes into a first insertion hole of the plurality of insertion holes while tilting the first heat transfer tube relatively to the first insertion hole, thereby inserting the first heat transfer tube while avoiding interference with the one protrusion or the plurality of protrusions; and after insertion, returning the tilt of the first heat transfer tube with respect to the first insertion hole to bring the first heat transfer tube into contact with the one protrusion or the plurality of protrusions.

[0107] (Appendix 2-17) The method for manufacturing a heat exchanger according to Appendix 2-16, wherein the assembling step includes fitting an inclination adjustment jig into the heat transfer tubes, the inclination adjustment jig being capable of holding the first heat transfer tube while tilting it relative to the first insertion hole, and inserting the first heat transfer tube into the first insertion hole while the inclination adjustment jig remains fitted into the heat transfer tubes.

[0108] (Appendix 2-18) A method for manufacturing an air conditioner that adjusts the temperature of an air-conditioned object and is equipped with a heat exchanger described in any one of Appendices 2-1 to 2-4, comprising: an assembly process for assembling the heat transfer tubes to the first header by inserting the heat transfer tubes into the insertion holes; and a joining process for brazing and joining the heat transfer tubes to the first header, wherein the joining process includes brazing a first heat transfer tube of the plurality of heat transfer tubes to a first insertion hole of the plurality of insertion holes while tilting the first heat transfer tube relative to the first insertion hole.

[0109] (Appendix 2-19) A method for manufacturing an air conditioner that adjusts the temperature of an air-conditioned object, and that is equipped with the heat exchanger described in any one of Appendices 2-5 to 2-8, comprising: an assembly step of assembling the plurality of heat transfer tubes to the first header by inserting the plurality of heat transfer tubes into the plurality of insertion holes; and a joining step of brazing the plurality of heat transfer tubes to the first header, wherein the assembly step includes: inserting the first heat transfer tube of the plurality of heat transfer tubes into a first insertion hole of the plurality of insertion holes while tilting it relatively to the first insertion hole, thereby inserting the first heat transfer tube while avoiding interference with the one protrusion or the plurality of protrusions; and after insertion, returning the tilt of the first heat transfer tube with respect to the first insertion hole, so that the first heat transfer tube comes into contact with the one protrusion or the plurality of protrusions.

[0110] (Appendix 2-20) The method for manufacturing an air conditioner described in Appendix 2-19 includes, in the assembly process, fitting an inclination adjustment jig into the plurality of heat transfer tubes, the inclination adjustment jig being capable of holding the first heat transfer tube while tilting it relative to the first insertion hole, and inserting the first heat transfer tube into the first insertion hole while the inclination adjustment jig remains fitted into the plurality of heat transfer tubes.

[0111] (Appendix 2-21) A manufacturing apparatus for manufacturing a heat exchanger according to any one of Appendices 2-1 to 2-13, comprising: a restraining device that restrains a core in which the plurality of heat transfer tubes and fins are alternately arranged; and a compression section that compresses the core.

[0112] (Appendix 2-22) A manufacturing apparatus for manufacturing the heat exchanger according to any one of Appendices 2-1 to 2-13, comprising: an assembly device that inserts the heat transfer tubes into the insertion holes and assembles the heat transfer tubes to the first header; and a joining device that brazes and joins the heat transfer tubes to the first header.

[0113] (Appendix 2-23) A manufacturing apparatus for manufacturing the heat exchanger according to any one of Appendices 2-5 to 2-8, comprising an inclination adjustment jig capable of holding the first heat transfer tube while tilting it relative to the first insertion hole.

[0114] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to illustrate the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and the meaning of equivalent disclosures are considered to be within the scope of the present disclosure.

[0115] This application is based on Japanese Patent Application No. 2024-075689, filed on May 8, 2024. The entire specification, claims, and drawings of Japanese Patent Application No. 2024-075689 are incorporated herein by reference.

[0116] 10, 10-2, 10-3, 10-4, 10-5: heat exchanger, 1: header, 1a: insertion hole, 1a-1: first insertion hole, 1a-2: second insertion hole, 1a-3: third insertion hole, 1c: flat surface, 1d: curved surface, 1e: protrusion, 2: heat transfer tube, 2-1: first heat transfer tube, 2-2: second heat transfer tube, 2-3: third heat transfer tube, 2a: hole, 2b: partition wall, 2c: flat surface, 2d: curved surface, 3: fin, 4: header, 4a: insertion hole, 4a-1: fourth insertion hole, 4a-2: fifth insertion hole, 4a-3: sixth insertion hole, 5, 6: side plate, 7: protrusion, 9: core, 11, 1 2: dent, 13: gap, 21: tilt adjustment jig, 21a: gap, 22: heat transfer tube holding part, C1, C2, C3, C4, C5, C6: contact part, E1, E2: end part, D1: longitudinal direction, D2: width direction, D3: longitudinal direction, D4: width direction, D5: longitudinal direction, D6: width direction, D7: longitudinal direction, D8: width direction, D10: tube axis direction, L1: height, L2: clearance, L3: hole width, L4: tube width, L10, L11: height, P1, P2, P4: center point, S1, S2, S3: center line, Y1, Y2, Y3: arrow, R1, R2: rotation direction.

Claims

1. A heat exchanger comprising: a first header having a plurality of insertion holes, each having an open cross section whose length in a second direction (a width direction orthogonal to a first direction) is shorter than its length in a first direction (a longitudinal direction), and the insertion holes are formed at intervals in the second direction; and a plurality of heat transfer tubes inserted into the insertion holes and through which a fluid flows, wherein the heat transfer tubes have cross sections whose length in a fourth direction (a width direction orthogonal to the third direction) is shorter than their length in a third direction (a longitudinal direction), a first of the plurality of insertion holes is inserted into a first of the plurality of insertion holes, the first direction of the first insertion hole being inclined with respect to the third direction of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and the first heat transfer tube is joined to the first header by brazing.

2. A heat exchanger as described in claim 1, wherein the heat transfer tubes are inserted into all of the plurality of insertion holes, all of the plurality of insertion holes are formed such that the first direction is inclined with respect to the third direction of each of the plurality of heat transfer tubes inserted into the plurality of insertion holes when viewed in the axial direction of the first heat transfer tube, and all of the plurality of heat transfer tubes are joined to all of the plurality of insertion holes by brazing.

3. A heat exchanger as described in claim 1, wherein a second heat transfer tube of the plurality of heat transfer tubes is inserted into a second insertion hole of the plurality of insertion holes, the second insertion hole is formed such that the first direction is parallel to the third direction of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube, and the second heat transfer tube is joined to the first header by brazing.

4. A heat exchanger as described in claim 3, wherein a third heat transfer tube of the plurality of heat transfer tubes is inserted into a third insertion hole of the plurality of insertion holes, the first insertion hole is formed between the second insertion hole and the third insertion hole, the third insertion hole is formed such that the first direction is inclined with respect to the third direction of the third heat transfer tube or is formed parallel to the third direction when viewed in the axial direction of the third heat transfer tube, and the third heat transfer tube is joined to the first header by brazing.

5. A heat exchanger comprising: a first header in which a plurality of insertion holes, each having an opening shape whose cross section is shorter in a second direction (a width direction perpendicular to a first direction) than in a first direction (a longitudinal direction), are formed at intervals in the second direction; and a plurality of heat transfer tubes inserted into the plurality of insertion holes and through which a fluid flows, wherein a first heat transfer tube of the plurality of heat transfer tubes is inserted into a first insertion hole of the plurality of insertion holes, and one protrusion or multiple protrusions are formed on the inner surface of the first insertion hole or the outer surface of the first heat transfer tube, and the one protrusion or the multiple protrusions are formed asymmetrically with respect to the center of the first insertion hole or the center of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube, and the first heat transfer tube is joined to the first header by brazing.

6. A heat exchanger as described in claim 5, wherein the heat transfer tubes are inserted into all of the insertion holes, one protrusion or multiple protrusions are formed on the inner surfaces of all of the insertion holes or on the outer surfaces of all of the heat transfer tubes, the one protrusion or multiple protrusions are formed asymmetrically with respect to the centers of the insertion holes or the centers of the heat transfer tubes when viewed in the axial direction of each of the heat transfer tubes, and the heat transfer tubes are joined to the first header by brazing.

7. A heat exchanger as described in claim 5, wherein a second heat transfer tube of the plurality of heat transfer tubes is inserted into a second insertion hole of the plurality of insertion holes, one protrusion or multiple protrusions are formed on the inner surface of the second insertion hole or the outer surface of the second heat transfer tube, the one protrusion or the multiple protrusions are formed asymmetrically with respect to the center of the second insertion hole or the center of the second heat transfer tube when viewed in the axial direction of the second heat transfer tube, and the second heat transfer tube is joined to the first header by brazing.

8. A heat exchanger as described in claim 7, wherein a third heat transfer tube of the plurality of heat transfer tubes is inserted into a third insertion hole of the plurality of insertion holes, the first insertion hole is formed between the second insertion hole and the third insertion hole, one protrusion or multiple protrusions are formed on the inner surface of the third insertion hole or the outer surface of the third heat transfer tube, the one protrusion or the multiple protrusions are formed asymmetrically with respect to the center of the third insertion hole or the center of the third heat transfer tube when viewed in the axial direction of the third heat transfer tube, and the third heat transfer tube is joined to the first header by brazing.

9. A heat exchanger according to any one of claims 1 to 8, wherein a protrusion protruding from the inner surface of the hole is formed at the end of the first insertion hole.

10. A heat exchanger as described in any one of claims 5 to 8, wherein the outer surface of the first heat transfer tube has a flat first flat surface, the inner surface of the first insertion hole has a flat second flat surface opposite to the first flat surface, and a recess is formed on the first flat surface or the second flat surface at a formation position where the one protrusion or the multiple protrusions contact.

11. A heat exchanger as described in any one of claims 1 to 4, comprising: a second header having a plurality of insertion holes formed at intervals in the sixth direction, each of which has an opening shape in cross section such that its length in a sixth direction, which is the width direction perpendicular to the fifth direction, is shorter than its length in the fifth direction, which is the longitudinal direction; a fourth insertion hole of the plurality of insertion holes of the second header into which the first heat transfer tube of the plurality of heat transfer tubes is inserted; the fourth insertion hole is formed so that the fifth direction is inclined with respect to the third direction of the first heat transfer tube when viewed in the axial direction of the first heat transfer tube; and the first heat transfer tube is joined to the second header by brazing.

12. A heat exchanger according to claim 11, wherein the fourth insertion hole is inclined to the same side as the inclination of the first insertion hole when viewed in the same tube axis direction.

13. A heat exchanger according to claim 11, wherein the fourth insertion hole is inclined in the opposite direction to the inclination of the first insertion hole when viewed in the same tube axis direction.

14. An air conditioner comprising a heat exchanger according to any one of claims 1 to 13 and for adjusting the temperature of an object to be air-conditioned.

15. A method for manufacturing a heat exchanger as defined in any one of claims 1 to 4, comprising: an assembly step of assembling the heat transfer tubes to the first header by inserting the heat transfer tubes into the insertion holes; and a joining step of brazing and joining the heat transfer tubes to the first header, wherein the joining step includes brazing the first heat transfer tube of the plurality of heat transfer tubes while tilting it relative to the first insertion hole of the plurality of insertion holes.

16. A method for manufacturing a heat exchanger as defined in any one of claims 5 to 8, comprising: an assembly step of assembling the plurality of heat transfer tubes to the first header by inserting the plurality of heat transfer tubes into the plurality of insertion holes; and a joining step of brazing and joining the plurality of heat transfer tubes to the first header, wherein the assembly step includes: inserting the first heat transfer tube of the plurality of heat transfer tubes into the first insertion hole of the plurality of insertion holes while tilting it relatively to the first insertion hole, thereby avoiding interference with the one protrusion or the plurality of protrusions; and after insertion, returning the tilt of the first heat transfer tube with respect to the first insertion hole to bring the first heat transfer tube into contact with the one protrusion or the plurality of protrusions.

17. A method for manufacturing a heat exchanger as described in claim 16, wherein the assembly process includes fitting an inclination adjustment jig into the plurality of heat transfer tubes, the inclination adjustment jig being capable of holding the first heat transfer tube while tilting it relative to the first insertion hole, and inserting the first heat transfer tube into the first insertion hole while the inclination adjustment jig remains fitted into the plurality of heat transfer tubes.

18. A method for manufacturing an air conditioner that is equipped with a heat exchanger as described in any one of claims 1 to 4 and adjusts the temperature of an air-conditioned object, comprising: an assembly process for assembling the plurality of heat transfer tubes to the first header by inserting the plurality of heat transfer tubes into the plurality of insertion holes; and a joining process for brazing and joining the plurality of heat transfer tubes to the first header, wherein the joining process includes brazing the first heat transfer tube of the plurality of heat transfer tubes while tilting it relatively to the first insertion hole of the plurality of insertion holes.

19. A method for manufacturing an air conditioner that adjusts the temperature of an object to be air-conditioned, comprising the heat exchanger of any one of claims 5 to 8, and includes an assembly step of assembling the plurality of heat transfer tubes to the first header by inserting the plurality of heat transfer tubes into the plurality of insertion holes, and a joining step of brazing the plurality of heat transfer tubes to the first header, wherein the assembly step includes inserting the first of the plurality of heat transfer tubes into the first of the plurality of insertion holes while tilting the first of the plurality of heat transfer tubes relative to the first insertion hole, thereby inserting the first of the plurality of heat transfer tubes while avoiding interference with the one protrusion or the plurality of protrusions, and after insertion, returning the tilt of the first heat transfer tube relative to the first insertion hole to bring the first heat transfer tube into contact with the one protrusion or the plurality of protrusions.

20. A method for manufacturing an air conditioner as described in claim 19, wherein the assembly process includes fitting an inclination adjustment jig into the plurality of heat transfer tubes, which is capable of holding the first heat transfer tube while tilting it relative to the first insertion hole, and inserting the first heat transfer tube into the first insertion hole while the inclination adjustment jig remains fitted into the plurality of heat transfer tubes.

21. A manufacturing apparatus for manufacturing a heat exchanger according to any one of claims 1 to 13, comprising: a restraining device for restraining a core in which the plurality of heat transfer tubes and fins are arranged alternately; and a compression section for compressing the core.

22. A manufacturing apparatus for manufacturing a heat exchanger according to any one of claims 1 to 13, comprising: an assembly device that inserts the heat transfer tubes into the insertion holes and assembles the heat transfer tubes to the first header; and a joining device that brazes and joins the heat transfer tubes to the first header.

23. A manufacturing apparatus for manufacturing a heat exchanger according to any one of claims 5 to 8, comprising an inclination adjustment jig capable of holding the first heat transfer tube while tilting it relative to the first insertion hole.