Heat exchanger and air-conditioning device comprising same

Abstract

This heat exchanger comprises: a plurality of flat tubes in which a fluid flows in the space demarcated by the walls of the tubes, the tubes having both end sections in the tube axis direction sealed and being arranged in a first direction intersecting the tube axis direction; and one or more headers that extend through and connect the plurality of flat tubes in the first direction. Each of the plurality of flat tubes is formed with one or more header insertion holes, which extend in the first direction, into which the one or more headers are inserted. Each of the one or more headers is formed with a communicating hole that communicates the interior of the header with the interiors of the plurality of flat tubes. Each of the plurality of flat tubes has, at least at one end section in the longitudinal direction, a bent section formed by bending a plate material constituting the wall of the tube.

Description

Heat exchanger and air conditioner equipped with the same

[0001] The present disclosure relates to a heat exchanger including a plurality of flat tubes and an air conditioner equipped with the same.

[0002] In heat exchangers, there has conventionally been a plate fin stacked type (see, for example, Patent Document 1). The heat exchanger of Patent Document 1 allows a second fluid such as air to flow between each plate fin stack of a plate fin stack having a flow path through which a first fluid such as a refrigerant flows, and performs heat exchange between the first fluid and the second fluid. The plate fins constituting the plate fin stack are configured to include a flow path region having a heat transfer flow path through which the first fluid flows by joining a pair of plates, and a header region having header flow paths on the inlet side and the outlet side communicating with the heat transfer flow paths of the flow path region. A large number of them are stacked to form a stacking interval through which the second fluid flows between the plate fins.

[0003] Japanese Patent Application Laid-Open No. 2020-176791

[0004] In the heat exchanger of Patent Document 1, when forming the plate fins constituting the flow path of the first fluid, it is necessary to join them over the entire circumference of the pair of plates. Therefore, since the number of joined portions increases and a larger margin is required, the size becomes larger. In addition, there is a concern that the joined portions may peel off, resulting in a problem that the strength also decreases.

[0005] The present disclosure has been made to solve the above problems, and an object thereof is to provide a heat exchanger capable of suppressing an increase in size and a decrease in strength, and an air conditioner equipped with the same.

[0006] The heat exchanger according to this disclosure comprises a plurality of flattened tubes arranged in a first direction intersecting the axial direction of the tubes, through which a fluid flows inside the tube wall, with both ends in the axial direction of the tubes sealed, and one or more headers that penetrate and connect the plurality of flattened tubes in the first direction, wherein each of the plurality of flattened tubes has one or more header insertion holes that penetrate in the first direction into which the one or more headers are inserted, each of the one or more headers has a communication hole that connects its interior to the interior of the plurality of flattened tubes, and each of the plurality of flattened tubes has a bent portion formed by bending the plate material constituting the tube wall at at least one end in the longitudinal direction.

[0007] Furthermore, the air conditioning system according to this disclosure includes a compressor, the heat exchanger, an expansion valve, and an indoor heat exchanger, all connected via piping, and is equipped with a fluid circuit through which the fluid circulates.

[0008] In the heat exchanger and air conditioning system equipped therewith, each of the multiple flattened tubes constituting the fluid flow path has a bent portion at at least one end in the longitudinal direction rather than a joined portion. Therefore, the number of joined portions can be reduced compared to conventional systems, thereby suppressing increases in size and a decrease in strength.

[0009] Figure 1 is a schematic external perspective view showing the general configuration of a heat exchanger according to Embodiment 1. Figure 2 is a schematic diagram showing the upper vertical cross section of the heat exchanger. Figure 2 is a vertical cross-sectional view showing the A-A section of the heat exchanger. Figure 2 is a partially enlarged view of the portion enclosed by the rectangle in the heat exchanger. Figure 4 is a horizontal cross-sectional view showing the B-B section of the heat exchanger. Figure 2 is a schematic external perspective view showing the flattened tube in the heat exchanger. Figure 2 is a schematic external perspective view showing a first modified example of the flattened tube in the heat exchanger. Figure 1 is a refrigerant circuit diagram of an air conditioning system equipped with the heat exchanger. Figure 2 is a schematic front view showing the sealing region of the flattened tube in the heat exchanger. Figure 2 is a schematic front view showing the sealing structure at the end of the flattened tube in the heat exchanger. Figure 2 is a schematic front view showing a first modified example of the sealing structure at the end of the flattened tube in the heat exchanger. Figure 2 is a schematic front view showing a second modified example of the sealing structure at the end of the flattened tube in the heat exchanger. This is a schematic front view showing a third modified example of the sealing structure at the end of the flat tube in the heat exchanger of Figure 2. This is a schematic front view showing a fourth modified example of the sealing structure at the end of the flat tube in the heat exchanger of Figure 2. This is a longitudinal cross-sectional view showing the joint between the flat tube and the header in the heat exchanger of Figure 4. This is a longitudinal cross-sectional view illustrating the length of the heat transfer fins in the heat exchanger of Figure 4. This is a longitudinal cross-sectional view showing a first modified example of the joint between the flat tube and the header in the heat exchanger of Figure 4. This is a longitudinal cross-sectional view showing a second modified example of the joint between the flat tube and the header in the heat exchanger of Figure 4. This is a longitudinal cross-sectional view showing a third modified example of the joint between the flat tube and the header in the heat exchanger of Figure 4. This is a longitudinal cross-sectional view showing a fourth modified example of the joint between the flat tube and the header in the heat exchanger of Figure 4. This is a transverse cross-sectional view showing a first modified example of the communication hole in the header of the heat exchanger of Figure 5. This is a transverse cross-sectional view showing a second modified example of the communication hole in the header of the heat exchanger of Figure 5. This is a longitudinal cross-sectional view showing a third modified example of the communication hole in the header of the heat exchanger of Figure 5. This is a longitudinal cross-sectional view showing a first modified example of the header in the heat exchanger of Figure 3. This is a longitudinal cross-sectional view showing a second modified example of the header in the heat exchanger of Figure 3. This is a schematic external perspective view showing a first modified example of the flow path configuration in the heat exchanger of Figure 1. This is a longitudinal cross-sectional view of the heat exchanger of Figure 26. This is a partial longitudinal cross-sectional view showing a C-C cross-section of the heat exchanger of Figure 27. This is a schematic external perspective view showing a second modified example of the flow path configuration in the heat exchanger of Figure 1.

[0010] The heat exchanger according to Embodiment 1 will be described below with reference to the drawings. Note that in the following drawings, including Figure 1, the relative dimensions and shapes of the components may differ from those of the actual components. Also, in the following drawings, components with the same reference numerals are the same or equivalent, and this is consistent throughout the entire specification. In addition, terms indicating direction (e.g., "up," "down," "right," "left," "front," "back") will be used as appropriate to facilitate understanding, but these notations are used only for the convenience of explanation and do not limit the arrangement and orientation of the device or components. In this specification, the positional relationships between components, the extension direction of each component, and the arrangement direction of each component are, in principle, those when the heat exchanger is installed in a usable state.

[0011] Embodiment 1. Figure 1 is an external perspective view showing the schematic configuration of the heat exchanger 101 according to Embodiment 1. Figure 2 is a schematic diagram showing the upper vertical cross-section of the heat exchanger 101 in Figure 1. Figure 3 is a vertical cross-sectional view showing the A-A section of the heat exchanger 101 in Figure 2. Figure 4 is a partially enlarged view of the portion enclosed by a rectangle in the heat exchanger 101 in Figure 2. Figure 5 is a horizontal cross-sectional view showing the B-B section of the heat exchanger 101 in Figure 4. Figure 6 is an external perspective view showing the flattened tube 10 in the heat exchanger 101 in Figure 2. Figure 7 is an external perspective view showing a first modified example of the flattened tube 10 in the heat exchanger 101 in Figure 2. Based on Figures 1 to 7, the configuration of the heat exchanger 101 according to Embodiment 1 will be described.

[0012] As shown in Figure 1, the heat exchanger 101 comprises a plurality of flattened tubes 10 arranged in a first direction D1 that intersects the tube axis direction (second direction D2), and two headers (upper header 61 and lower header 62) that penetrate the ends of the plurality of flattened tubes 10 on both sides in the tube axis direction in the first direction D1. The plurality of flattened tubes 10 are arranged in the first direction D1 at a predetermined tube pitch Lp (see Figure 2). The heat exchanger 101 also comprises a plurality of heat transfer fins 50.

[0013] In the heat exchanger 101, each flattened tube 10 extends in the direction along the tube axis Ax (see Figure 2) (i.e., in the direction of the tube axis), and has a flattened shape that is elongated in one direction in a cross section perpendicular to the tube axis Ax. Hereinafter, the first direction D1 in which the multiple flattened tubes 10 are arranged will be called the arrangement direction, the direction in the direction of the tube axis of the flattened tube 10 will be called the second direction D2, the longitudinal direction of the flattened tube 10, or the short axis direction of the flattened tube 10, and the longitudinal direction of the cross section of the flattened tube 10 will be called the third direction D3, the short axis direction of the flattened tube 10, or the long axis direction of the flattened tube 10. Furthermore, hereafter, the heat exchanger 101 is defined as being installed so that the arrangement direction of the flattened tubes 10 (first direction D1) is in the left-right direction. Furthermore, each flattened tube 10 is defined as being arranged such that its tube axis Ax is in the vertical direction perpendicular to the arrangement direction (first direction D1), and its short side direction (third direction D3) is in the front-to-back direction perpendicular to the tube axis direction and the arrangement direction.

[0014] The arrangement of the heat exchanger 101, or the angle between the arrangement direction of the flattened tubes 10 in the heat exchanger 101 (first direction D1) and the tube axis direction of each flattened tube 10 (second direction D2), is not limited to the above case. For example, the heat exchanger 101 may be tilted so that the tube axis direction of each flattened tube 10 is inclined relative to the vertical direction. Alternatively, the heat exchanger 101 may be configured such that, when the arrangement direction of the flattened tubes 10 (first direction D1) is in the left-right direction, the tube axis direction of each flattened tube 10 is inclined relative to the vertical direction.

[0015] As shown in Figures 2 and 5, gaps that serve as air passages P2 are formed between the tube walls 11 of adjacent flattened tubes 10 in the arrangement direction (first direction D1), and in the heat exchanger 101, air flows through each gap along the shorter direction (third direction D3) of the flattened tubes 10.

[0016] In Figure 1, a first pipe a and a second pipe b, which serve as inlets and outlets for the fluid (e.g., refrigerant) in the heat exchanger 101, are provided at the right end of the upper header 61 and the right end of the lower header 62. Here, the fluid flowing through the flattened pipes 10 may be a refrigerant, water, brine, etc. A fluid flow path is provided between the first pipe a and the second pipe b in the heat exchanger 101. Specifically, as shown in Figure 2, the fluid flow path is composed of the internal spaces of the multiple flattened pipes 10, the internal space of the upper header 61, and the internal space of the lower header 62. The heat exchanger 101 performs heat exchange between air and fluid. In the following explanation, the fluid flowing through the multiple flattened pipes 10 is defined as a refrigerant.

[0017] As shown in Figure 1, a header insertion hole 10h1 is formed at the upper end of each flattened tube 10, penetrating in a first direction D1 into which the upper header 61 is inserted, and a header insertion hole 10h2 is formed at the lower end of each flattened tube 10, penetrating in a first direction D1 into which the lower header 62 is inserted. The flattened tube 10 has a pipe structure in which an internal space through which the refrigerant flows is maintained along its longitudinal direction (second direction D2), that is, from the upper end to the lower end of the tube wall 11. The open ends 10e on both sides of the flattened tube 10 in the longitudinal direction are sealed. The sealing structure will be described later.

[0018] As shown in Figures 2, 5, and 6, the pipe wall 11 of the flattened pipe 10 has a substantially flat first pipe side wall portion 10a and a second pipe side wall portion 10b facing each other in the short axis direction (first direction D1) of the flattened pipe 10, a curved bend portion 10c located between the first pipe side wall portion 10a and the second pipe side wall portion 10b and bent so that the first pipe side wall portion 10a and the second pipe side wall portion 10b face each other, and a joint portion 10d facing the bend portion 10c in the long axis direction (third direction D3) of the flattened pipe 10 and joining the first pipe side wall portion 10a and the second pipe side wall portion 10b at the ends of the first pipe side wall portion 10a and the second pipe side wall portion 10b in the third direction D3. The first pipe side wall portion 10a and the second pipe side wall portion 10b are joined by joining means such as brazing, adhesive, welding, or pressure welding. The flattened pipe 10 is formed by bending a single sheet material at one bend portion 10c and joining it at one joint portion 10d, thereby creating a pipe structure that maintains an internal space through which the refrigerant flows.

[0019] The pipe wall 11 of the flattened pipe 10 is not limited to the above structure, and may have the following structure. That is, as shown in Figures 2, 5, and 7, the pipe wall 11 of the flattened pipe 10 has a substantially flat first pipe side wall portion 10a and a second pipe side wall portion 10b facing each other in the short axis direction (first direction D1) of the flattened pipe 10, a curved bend portion 10c located between the first pipe side wall portion 10a and the second pipe side wall portion 10b, which is bent so that the first pipe side wall portion 10a and the second pipe side wall portion 10b face each other, and faces each other in the long axis direction (third direction D3) of the flattened pipe 10, and a joint portion 10d which is a portion that joins the portion extending from the center of one of the first pipe side wall portion 10a and the center of the other pipe side wall portion 10b with the aforementioned center portion of the other pipe side wall portion. Furthermore, the portion extending from the center of one of the first pipe sidewalls 10a and the second pipe sidewall 10b to the center of the other may be joined to the other center by brazing or adhesive or other joining means. The flattened pipe 10 is formed by bending a single sheet material at two bends 10c and joining them at one joint 10d, thereby creating a pipe structure that maintains an internal space through which the refrigerant flows. In addition, as shown in Figure 7, in a configuration where the flow path inside the flattened pipe 10 is divided into two in a third direction D3 by the joint 10d, a header insertion hole 10h1 may be provided in each, and the refrigerant may be distributed to each flow path from the two headers.

[0020] As shown in Figures 6 and 7, the joint portion 10d is the part where a single plate material is joined to form a tube. This joint portion 10d extends in the direction of the tube axis (second direction D2) and is formed at only one location in the circumferential direction of the flattened tube 10. In this way, since the joint portion 10d, which is the part to be joined, is formed at only one location in the circumferential direction, the amount of joining can be reduced compared to conventional designs, thereby suppressing an increase in size and a decrease in strength. Furthermore, the joint portion 10d is formed at a position offset in the third direction D3 from the header insertion holes 10h1 and 10h2. In this way, by forming the joint portion 10d at a position that does not overlap with the header insertion holes 10h1 and 10h2, a decrease in the strength of the flattened tube 10 can be suppressed.

[0021] The method for forming the flattened tube 10 according to Embodiment 1 is roll forming. However, the method for forming the flattened tube 10 may also be extrusion or drawing, in addition to roll forming.

[0022] As shown in Figures 2 and 3, the first pipe side wall portion 10a and the second pipe side wall portion 10b each have a rectangular shape with the longer side extending in the longitudinal direction (second direction D2) of the flattened pipe 10 and the shorter side extending in the short direction (third direction D3) of the flattened pipe 10. The first pipe side wall portions 10a and 10b are each flat, but "flat" here does not have to be a surface composed of a perfectly flat plane; it is sufficient if the structure as a whole appears to spread out in a planar manner. For example, depressions, protrusions, or corrugations may be formed in a part of the area that spreads out in a planar manner. In Figure 2, the left wall portion of the pipe wall 11 is the first pipe side wall portion 10a (hereinafter also referred to as the flattened plane), and the right wall portion of the pipe wall 11 is the second pipe side wall portion 10b (hereinafter also referred to as the flattened plane).

[0023] As shown in Figure 2, a first hole ha is formed in the left side wall portion 10a of the first pipe, penetrating in the first direction D1, and a second hole hb is formed in the right side wall portion 10b of the second pipe, penetrating in the first direction D1. The header insertion hole 10h1 is composed of the first hole ha and the second hole hb. The shapes of the first hole ha and the second hole hb are, for example, circular (see Figure 3). The configuration of the header insertion hole 10h2 into which the lower header 62 is inserted is the same as the configuration of the header insertion hole 10h1 into which the upper header 61 is inserted, and is composed of a first hole ha formed in the first pipe side wall portion 10a and a second hole hb formed in the second pipe side wall portion 10b.

[0024] As shown in Figure 1, the header insertion holes 10h1 and 10h2 are located inside the open ends 10e on both sides in the longitudinal direction (second direction D2) of the flattened tube 10. In the heat exchanger 101 arranged as shown in Figure 1, the header insertion holes 10h1 and 10h2 of each flattened tube 10 are located below the upper open end 10e of the flattened tube 10 and above the lower open end 10e of the flattened tube 10.

[0025] As shown in Figure 1, the upper header 61 and the lower header 62 each pass through and connect multiple flat pipes 10. The upper header 61 and the lower header 62 have, for example, a cylindrical shape. In Figure 1, the left ends of the upper header 61 and the lower header 62 that are not used as refrigerant inlets or outlets are sealed.

[0026] As shown in Figure 4, the upper header 61 has multiple communication holes 60h that connect its internal space to the internal spaces of the multiple flattened pipes 10. In the upper header 61, the multiple communication holes 60h are formed at the same interval Lh as the pipe pitch Lp in the first direction D1 of the multiple flattened pipes 10. Although not shown, the lower header 62 in Figure 1 also has multiple communication holes 60h that connect its internal space to the internal spaces of the multiple flattened pipes 10.

[0027] In other words, the refrigerant flow path of the heat exchanger 101 includes a heat transfer flow path P1a provided within the tube wall 11 of each flat tube 10 and extending in the longitudinal direction (second direction D2) of the flat tube 10, and a header flow path P1h provided inside the upper header 61 and the lower header 62, extending in the direction of arrangement of the multiple flat tubes 10 (first direction D1) and connecting the heat transfer flow paths P1a of the multiple flat tubes 10 to each other.

[0028] In the examples shown in Figures 4 and 5, the multiple communication holes 60h are provided at the lower circumferential end of the upper header 61 extending in the first direction D1. The communication holes 60h have, for example, a circular shape (see Figure 5). Also, in the examples shown in Figures 4 and 5, the center of the communication hole 60h is provided to coincide with the center of the flattened pipe 10 in the first direction D1, and one communication hole 60h is provided for each flattened pipe 10. Furthermore, in the first direction D1, the communication hole 60h is provided such that its width, i.e., diameter, is approximately the same as the width W of the heat transfer flow path P1a of the flattened pipe 10, i.e., the distance between the first pipe side wall portion 10a and the second pipe side wall portion 10b. The lower part of the heat exchanger 101 has a structure that is generally the same as the upper part of the heat exchanger 101 when inverted vertically, and in the lower header 62, the multiple communication holes 60h are provided at the upper circumferential end of the lower header 62. The position, number, and shape of the communication holes 60h in each header (upper header 61 and lower header 62) are not limited to those described above. Other configurations of the communication holes 60h in each header will be described later.

[0029] The outer surfaces of each header (upper header 61, lower header 62) are joined to the inner surfaces of the header insertion holes 10h1 and 10h2 of the multiple flattened pipes 10 by brazing or other joining means such as adhesive.

[0030] The heat exchanger 101 in Figure 1 is equipped with corrugated fins as an example of heat transfer fins 50, which connect the opposing first pipe sidewalls 10a and second pipe sidewalls 10b of adjacent flat pipes 10 in each gap, i.e., the airflow path P2, of the multiple flat pipes 10. In this case, the opposing first pipe sidewalls 10a and second pipe sidewalls 10b of adjacent flat pipes 10 and the heat transfer fins 50 are brazed together. By providing heat transfer fins 50, heat exchange between the refrigerant and air is promoted, and the heat exchange performance of the heat exchanger 101 is improved.

[0031] Figure 8 is a refrigerant circuit diagram of the air conditioning system 100 equipped with the heat exchanger 101 shown in Figure 1. As shown in Figure 8, the heat exchanger 101 constitutes a part of the refrigerant circuit 100c through which the refrigerant circulates in the air conditioning system 100.

[0032] The air conditioning system 100 includes a compressor 102, a heat exchanger 101, an expansion valve 105, an indoor heat exchanger 104, and a four-way valve 103. In Figure 8, the compressor 102, heat exchanger 101, expansion valve 105, and four-way valve 103 are installed in the outdoor unit 100A, and the indoor heat exchanger 104 is installed in the indoor unit 100B. The first pipe a and second pipe b (see Figure 1), which serve as the refrigerant inlet and outlet for the heat exchanger 101, are connected to the four-way valve 103 and expansion valve 105 of the refrigerant circuit 100c.

[0033] The compressor 102, heat exchanger 101, expansion valve 105, indoor heat exchanger 104, and four-way valve 103 are connected to each other via refrigerant piping (also simply called piping), thereby forming a refrigerant circuit 100c that allows the refrigerant to circulate. In the air conditioning system 100, when the compressor 102 operates, a refrigeration cycle is performed in which the refrigerant circulates through the compressor 102, heat exchanger 101, expansion valve 105, and indoor heat exchanger 104 while undergoing phase change.

[0034] The outdoor unit 100A is equipped with an outdoor fan 107 that forces outdoor air to pass through the heat exchanger 101. The heat exchanger 101 performs heat exchange between the airflow of outdoor air generated by the operation of the outdoor fan 107 and the refrigerant. The indoor unit 100B is equipped with an indoor fan 106 that forces indoor air to pass through the indoor heat exchanger 104. The indoor heat exchanger 104 performs heat exchange between the airflow of indoor air generated by the operation of the indoor fan 106 and the refrigerant.

[0035] The operation of the air conditioning system 100 can be switched between cooling and heating modes. In Figure 8, the direction of refrigerant flow during cooling operation is shown by a dashed arrow, and the direction of refrigerant flow during heating operation is shown by a solid arrow. The four-way valve 103 is a solenoid valve that switches the refrigerant flow path according to the switching between cooling and heating modes of the air conditioning system 100. Alternatively, a combination of two-way and three-way valves may be used to switch the refrigerant flow path instead of the four-way valve 103. During cooling operation, the four-way valve 103 guides refrigerant from the compressor 102 to the heat exchanger 101 and refrigerant from the indoor heat exchanger 104 to the compressor 102. During heating operation, it guides refrigerant from the compressor 102 to the indoor heat exchanger 104 and refrigerant from the heat exchanger 101 to the compressor 102.

[0036] During cooling operation of the air conditioning system 100, the refrigerant compressed by the compressor 102 is sent to the heat exchanger 101. In the heat exchanger 101, the refrigerant releases heat to the outside air and condenses. After this, the refrigerant is sent to the expansion valve 105, where it is depressurized, and then sent to the indoor heat exchanger 104. After this, the refrigerant absorbs heat from the indoor air in the indoor heat exchanger 104 and evaporates, before returning to the compressor 102. Therefore, during cooling operation of the air conditioning system 100, the heat exchanger 101 functions as a condenser, and the indoor heat exchanger 104 functions as an evaporator.

[0037] During heating operation of the air conditioning system 100, the refrigerant compressed by the compressor 102 is sent to the indoor heat exchanger 104. In the indoor heat exchanger 104, the refrigerant releases heat into the indoor air and condenses. After this, the refrigerant is sent to the expansion valve 105, where it is depressurized, and then sent to the heat exchanger 101. After this, the refrigerant absorbs heat from the outside air in the heat exchanger 101 and evaporates, before returning to the compressor 102. Therefore, during heating operation of the air conditioning system 100, the heat exchanger 101 functions as an evaporator, and the indoor heat exchanger 104 functions as a condenser.

[0038] Next, an example of the operation of the heat exchanger 101 will be explained using Figures 1, 2, and 8. As shown by the white arrows in Figure 1, the refrigerant flows into the heat exchanger 101 from the first pipe a. As shown in Figure 2, in the heat exchanger 101, the refrigerant first flows into the header flow path P1h of the upper header 61 and flows from right to left through the header flow path P1h. In this process, the refrigerant is distributed to a plurality of flat pipes 10 from the communication holes 60h provided in the upper header 61 and flows into the heat transfer flow path P1a of each flat pipe 10. In each heat transfer flow path P1a, the refrigerant flows downward. At this time, the refrigerant exchanges heat with the air flowing through the gaps between the pipe walls 11 of the flat pipes 10 (i.e., the air flow path P2) via the pipe walls 11. The refrigerants from the multiple heat transfer channels P1a flow into the header channel P1h of the lower header 62, which penetrates the lower ends of the multiple flat pipes 10, through multiple communication holes 60h, and merge in the header channel P1h. The refrigerants that merge in the header channel P1h flow out from the second pipe b provided at the right end of the lower header 62 to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c shown in Figure 8).

[0039] Figure 9 is a schematic front view showing the sealing region of the flat tube 10 in the heat exchanger 101 of Figure 2. Figure 10 is a schematic front view showing the sealing structure at the end of the flat tube 10 in the heat exchanger 101 of Figure 2. Figure 11 is a schematic front view showing a first modified example of the sealing structure at the end of the flat tube 10 in the heat exchanger 101 of Figure 2. Figure 12 is a schematic front view showing a second modified example of the sealing structure at the end of the flat tube 10 in the heat exchanger 101 of Figure 2. Figure 13 is a schematic front view showing a third modified example of the sealing structure at the end of the flat tube 10 in the heat exchanger 101 of Figure 2. Figure 14 is a schematic front view showing a fourth modified example of the sealing structure at the end of the flat tube 10 in the heat exchanger 101 of Figure 2. Note that Figures 9 to 14 only show the upper end of the flat tube 10, but the lower end has a similar structure.

[0040] The ends of the multiple flattened tubes 10 in the axial direction (second direction D2) have a sealing structure in which the open ends 10e are individually sealed. As shown in Figure 9, the ends of the multiple flattened tubes 10 in the axial direction (second direction D2) have a sealed region SR that extends from the joint portion 10d in the longitudinal direction (third direction D3) of the flattened tube 10, which is perpendicular to the axial direction. In this way, the sealed region (region SR) at both ends of the flattened tube 10 in the axial direction is longer in the longitudinal direction than in the axial direction, so the length of the flattened tube 10 in the axial direction can be reduced. Note that it is sufficient if at least one of the sealed regions (region SR) at both ends of the flattened tube 10 in the axial direction is longer in the longitudinal direction than in the axial direction.

[0041] The sealing structure for sealing both ends of the flattened tube 10 in the axial direction (second direction D2) is a structure in which both ends of the flattened tube 10 in the axial direction are crushed and sealed, as shown in Figure 10. However, it is not limited to this, and as shown in Figure 11, after crushing and sealing both ends of the flattened tube 10 in the axial direction, the tip is bent in the opposite direction (180 degrees). In this way, by sealing both ends of the flattened tube 10 in the axial direction as shown in Figure 10 or Figure 11, no separate parts are required when sealing both ends of the flattened tube 10 in the axial direction, and sealing can be done with a simple structure, thus reducing manufacturing costs.

[0042] Further, as shown in FIG. 12, a structure in which concave cap members 20 covering the open ends 10e are attached to both ends of the flat tube 10 in the tube axis direction (second direction D2) may be used. Alternatively, as shown in FIG. 13, after both ends of the flat tube 10 in the tube axis direction are crushed and sealed, a structure in which a concave cap member 20A is attached to the tip end thereof may be used. Further, as shown in FIG. 14, a structure in which cap members 20B having a plurality of recesses 20a covering the open ends 10e formed at both ends of the flat tube 10 in the tube axis direction at the same interval as the tube pitch Lp of the flat tube 10 in the first direction D1 is attached may be used. In the structures shown in FIGS. 12 and 13, the same number of cap members 20 as the number of flat tubes 10 are attached to both ends of the plurality of flat tubes 10 in the tube axis direction. In the structure shown in FIG. 14, one cap member 20B is attached to both ends of the plurality of flat tubes 10 in the tube axis direction. By adopting any of the sealing structures shown in FIGS. 12 to 13 for both ends of the flat tube 10 in the tube axis direction, both ends of the flat tube 10 in the tube axis direction can be firmly sealed by the cap members 20, 20A, and 20B, so that refrigerant leakage can be more reliably prevented.

[0043] Incidentally, both ends of the plurality of flat tubes 10 in the tube axis direction (second direction D2) may have different sealing structures. For example, one end of the plurality of flat tubes 10 in the tube axis direction (second direction D2) has the sealing structure shown in FIG. 10, and the other end of the plurality of flat tubes 十 in the tube axis direction (second direction D2) has the sealing structure shown in FIG. 11.

[0044] FIG. 15 is a longitudinal sectional view showing a joint portion between the flat tube 10 and the header in the heat exchanger 101 of FIG. 4. Peripheral protrusions 12 (hereinafter also referred to as joint portions) extending in the first direction D1 are provided at the peripheral portions of the header insertion holes 10h1 in each of the plurality of flat tubes 10. Although not shown, peripheral protrusions 12 extending in the first direction D1 are also provided at the peripheral portions of the header insertion holes 10h2 in each of the plurality of flat tubes 10, similar to the peripheral portions of the header insertion holes 10h1.

[0045] Specifically, the peripheral convex portion 12 is composed of a first peripheral convex portion 12a formed at the peripheral portion of the first hole ha on the left first pipe side wall portion 10a and a second peripheral convex portion 12b formed at the peripheral portion of the second hole hb on the right second pipe side wall portion 10b. The first peripheral convex portion 12a and the second peripheral convex portion 12b are provided in opposite directions so as to protrude outward from the pipe wall 11 of the flat tube 10. That is, the first peripheral convex portion 12a extends leftward from the left first pipe side wall portion 10a, and the second peripheral convex portion 12b extends rightward from the right second pipe side wall portion 10b. Each of the first peripheral convex portion 12a and the second peripheral convex portion 12b is joined to the outer peripheral surface of each header (upper header 61, lower header 62) so as to maintain the airtightness inside each flat tube 10.

[0046] In each header (upper header 61, lower header 62), each of the plurality of communication holes 60h is arranged between the tip of the first peripheral convex portion 12a and the tip of the second peripheral convex portion 12b of the flat tubes 10 that communicate with each other in the first direction D1.

[0047] When the width Wh of the communication hole 60h is made substantially the same as the width W of the heat transfer flow path P1a of the flat tube 10 in the first direction D1, if the position of the communication hole 60h in the first direction D1 is shifted with respect to the flat tube 10, there is a concern about refrigerant leakage. In a configuration where the peripheral convex portion 12 protruding outward is provided at the peripheral portions of the header insertion holes 10h1 and 10h2 as shown in FIG. 15, compared with a configuration where there is no peripheral convex portion 12 at the peripheral portions of the header insertion holes 10h1 and 10h2, even if the position of the communication hole 60h of the header is slightly shifted with respect to the flat tube 10 in the first direction D1, the refrigerant leakage can be suppressed by the peripheral convex portion 12 extending outward from the pipe wall 11. Therefore, the diameter of the communication hole 60h of the header may be made larger than the width W of the heat transfer flow path P1a of the flat tube 10. Further, since it is joined to each flat tube 10 by the peripheral convex portion 12, the airtightness inside each flat tube 10 can be maintained, and the airtightness can be improved. Further, since each flat tube 10 is held by each header, the strength of each flat tube 10 can be improved.

[0048] Such a flattened tube 10 can be manufactured, for example, by pre-forming a plate material that is the base material for the flattened tube 10 with a first hole ha, a second hole hb, a first peripheral protrusion 12a, and a second peripheral protrusion 12b, respectively, for header insertion holes 10h1 and 10h2, and then forming the plate material by roll forming. Alternatively, the first peripheral protrusion 12a and the second peripheral protrusion 12b may be formed by raising the peripheral edge when forming the first hole ha and the second hole hb in the plate material that is the base material for the flattened tube 10, for example, by burring.

[0049] Figure 16 is a longitudinal cross-sectional view illustrating the length of the heat transfer fins 50 in the heat exchanger 101 of Figure 4. As described above, the heat transfer fins 50 are brazed to the opposing first pipe sidewall portion 10a and second pipe sidewall portion 10b of adjacent flat pipes 10. Therefore, as shown in Figure 16, the length of the heat transfer fins 50 in the first direction D1 is the distance Lb between the opposing first pipe sidewall portion 10a and second pipe sidewall portion 10b of adjacent flat pipes 10. Furthermore, the length of the heat transfer fins 50 in the first direction D1 (= distance Lb) is longer than the distance La in the first direction D1 between the peripheral protrusions 12 of adjacent flat pipes 10, and a part of the outer surface of the header is exposed to the outside. With this configuration, the heat transfer fins 50 become larger, which reduces airflow resistance and improves heat exchange performance. Furthermore, it is possible to form a good joint without interference between adjacent flattened pipes 10, and the arrangement pitch of the flattened pipes 10 can be freely designed.

[0050] Figure 17 is a longitudinal cross-sectional view showing a first modified example of the joint between the flattened tube 10 and the header in the heat exchanger 101 of Figure 4. In the example of Figure 17, the first peripheral projection 12a and the second peripheral projection 12b are provided in the same direction in the first direction D1 from the tube wall 11 of the flattened tube 10. In Figure 17, the first peripheral projection 12a extends to the left from the left side of the first tube side wall 10a, and the second peripheral projection 12b extends to the left from the right side of the second tube side wall 10b. The first peripheral projection 12a and the second peripheral projection 12b are joined to the outer surface of each header (upper header 61, lower header 62) in order to maintain airtightness inside each flattened tube 10.

[0051] In each header (upper header 61, lower header 62), each of the multiple communication holes 60h is positioned in the first direction D1 between the tip of the first peripheral protrusion 12a of a communicating flat pipe 10 and the outer surface of the second pipe side wall 10b.

[0052] As shown in Figure 17, in a configuration where peripheral protrusions 12 extending in one direction D1 (to the left in Figure 17) are provided on the periphery of the header insertion holes 10h1 and 10h2, refrigerant leakage can be suppressed by the first peripheral protrusions 12a extending from the pipe wall 11, even if the position of the communication hole 60h of the header is slightly shifted in one direction (to the left) relative to the flat pipe 10. For this reason, the diameter of the communication hole 60h of the header may be made larger than the width W of the heat transfer flow path P1a of the flat pipe 10. Also, since the peripheral protrusions 12 are joined to each flat pipe 10, airtightness inside each flat pipe 10 can be maintained, improving airtightness. Furthermore, since each flat pipe 10 is held by each header, the strength of each flat pipe 10 can be improved.

[0053] Figure 18 is a longitudinal cross-sectional view showing a second modified example of the joint between the flat tube 10 and the header in the heat exchanger 101 of Figure 4. In the example of Figure 18, a joining member 25 (hereinafter also referred to as the joint) that is joined to the outer circumference of the header is provided on the periphery of the header insertion hole 10h1 in each of the multiple flat tubes 10. This joining member 25 is separate from the flat tube 10. Although not shown, in each of the multiple flat tubes 10, a joining member 25 that is joined to the outer circumference of the header is also provided on the periphery of the header insertion hole 10h2, similar to the periphery of the header insertion hole 10h1.

[0054] Furthermore, the joining member 25 has an outer diameter larger than the header insertion holes 10h1 and 10h2, and includes a flat pipe joining surface 25a that extends in the second direction D2 and is joined to the first pipe side wall portion 10a or the second pipe side wall portion 10b of the flat pipe 10, and a header joining surface 25b that extends in the first direction D1 and is joined to the outer circumferential surface of the header. The relative sizes of the header's outer diameter d1, the header insertion holes 10h1 and 10h2's diameters d2, the header joining surface 25b's inner diameter d3, and the flat pipe joining surface's outer diameter d4 are such that the header's outer diameter d1 ≈ the header joining surface 25b's inner diameter d3 < the header insertion holes 10h1 and 10h2's diameters d2 < the flat pipe joining surface's outer diameter d4. Although the joining member 25 is separate from the member on the first pipe side wall portion 10a and the member on the second pipe side wall portion 10b, it may also be configured to have a joining member (not shown) that connects the members on both sides inside the header insertion holes 10h1 and 10h2, provided that at least a part of the communication hole 60h is not covered.

[0055] Figure 19 is a longitudinal cross-sectional view showing a third modified example of the joint between the flattened tube 10 and the header in the heat exchanger 101 of Figure 4. The shape of the jointing member 25 may be such that the distance of the joint portion is wider than the distance between the first pipe side wall portion 10a and the second pipe side wall portion 10b of the flattened tube 10 (i.e., the width W of the heat transfer flow path P1a of the flattened tube 10) (tapered shape), as shown in Figure 19.

[0056] As shown in the examples of Figures 18 and 19, a joining member 25 is provided on the periphery of the header insertion hole 10h1 in each of the multiple flat tubes 10, which is joined to the outer circumference of the header. Therefore, as in the examples of Figures 15 and 16, even if the position of the communication hole 60h of the header is slightly misaligned with respect to the flat tube 10 in the first direction D1, refrigerant leakage can be suppressed by the header joining surface 25b extending in the first direction D1. For this reason, the diameter of the communication hole 60h of the header may be made larger than the width W of the heat transfer flow path P1a of the flat tube 10. In addition, since each flat tube 10 is joined by the joining member 25, airtightness inside each flat tube 10 can be maintained, and airtightness can be improved. Furthermore, since each flat tube 10 is held by each header, the strength of each flat tube 10 can be improved.

[0057] Furthermore, although not shown in the diagram, the length (= spacing Lb) of the heat transfer fins 50 in the first direction D1 is longer than the spacing in the first direction D1 of the joining members provided on adjacent flat pipes 10, and a portion of the outer surface of the header is exposed to the outside. With this configuration, the heat transfer fins 50 become larger, which reduces airflow resistance and improves heat exchange performance. Moreover, it does not interfere with the joints of adjacent flat pipes 10, allowing for the formation of a good joint, and the arrangement pitch of the flat pipes 10 can be freely designed.

[0058] Figure 20 is a longitudinal cross-sectional view showing a fourth modified example of the joint between the flattened tube 10 and the header in the heat exchanger 101 of Figure 4. In the example of Figure 20, the first peripheral projection 12a and the second peripheral projection 12b are provided in opposite directions so as to protrude outward from the tube wall 11 of the flattened tube 10, and the first peripheral projection 12a and the second peripheral projection 12b each have inclined tapered portions 12at and 12bt on the base end side. The tips 12ae and 12be of the first peripheral projection 12a and the second peripheral projection 12b extend in a first direction D1 along the outer circumferential surface of the header. The tips 12ae and 12be are joined to the outer circumferential surface of the header.

[0059] The tapered portion 12at of the first peripheral protrusion 12a is an annular portion whose opening diameter decreases as it moves from the first pipe side wall portion 10a toward the left tip portion 12ae. The tapered portion 12bt of the second peripheral protrusion 12b is an annular portion whose opening diameter decreases as it moves from the second pipe side wall portion 10b toward the right tip portion 12be. In other words, the first peripheral protrusion 12a and the second peripheral protrusion 12b each have a shape in which the base end side is bulging compared to the tip portions 12ae and 12be which are joined to the outer circumferential surface of the header.

[0060] As shown in the example in Figure 20, the first peripheral protrusion 12a and the second peripheral protrusion 12b each have tapered portions 12at and 12bt, respectively. This makes it possible to make the width Wh of each communication hole 60h of the header larger than the width W of the heat transfer flow path P1a of the flattened pipe 10, that is, the distance between the first pipe side wall portion 10a and the second pipe side wall portion 10b in the first direction D1.

[0061] The following describes other configuration examples of the communication holes 60h in the headers. Figure 21 is a cross-sectional view showing a first modified example of the communication holes 60h in the headers of the heat exchanger 101 in Figure 5. In the example in Figure 5, each header (upper header 61, lower header 62) was provided with one communication hole 60h for each flat pipe 10, but in the example in Figure 21, each header is provided with two communication holes 60h for each flat pipe 10. Specifically, in the lower half of the peripheral wall of the upper header 61, two communication holes 60h are provided in the circumferential direction of the header, one behind and one in front of the pipe axis Ax of the flat pipe 10. Also, in the upper half of the peripheral wall of the lower header 62, two communication holes 60h are provided in the circumferential direction of the header, one behind and one in front of the pipe axis Ax of the flat pipe 10. Note that each header may be provided with three communication holes 60h for each flat pipe 10. In this way, by providing multiple communication holes 60h for each flat tube 10 in each header, even if the heat exchanger 101 is tilted or deformed, the refrigerant can be uniformly distributed from each header to each flat tube 10, thereby improving distribution performance.

[0062] Figure 22 is a cross-sectional view showing a second modified example of the communication hole 60h in the header of the heat exchanger 101 in Figure 5. In the example in Figure 5, the shape of the communication hole 60h was circular, but in the example in Figure 22, the communication hole 60h is slit-shaped and extends in the third direction D3. By making the communication hole 60h extend in the third direction D3 in this way, the communication hole 60h is expanded in the longitudinal direction of the cross-section of the flattened tube 10, and the bias in the third direction D3 of the refrigerant flowing from the header flow path P1h into the heat transfer flow path P1a of the flattened tube 10 is mitigated.

[0063] Figure 23 is a longitudinal cross-sectional view showing a third modified example of the communication hole 60h in the header of the heat exchanger 101 in Figure 5. In the example of Figure 5, the communication hole 60h was provided at the lower end of the upper header 61, but in the example of Figure 23, the communication hole 60h is provided in a predetermined angular range in the circumferential direction of the upper header 61 so as to be near the liquid level of the refrigerant inside the upper header 61. An example of the angular range of the communication hole 60h will be described below. The heat exchanger 101 is defined as one in which the pipe axis direction of the flattened pipes 10 is in the vertical direction.

[0064] In the following explanation, the angle Φ of the communication hole 60h is the angle viewed from the center Ch from the lower end of the vertical line passing through the center Ch of the header peripheral wall to the position of the communication hole 60h. That is, the circumferential position of the communication hole 60h is represented by the angle Φ when the vertical downward direction of the center Ch is set to 0 degrees. The communication hole 60h is provided such that the angle Φ of the communication hole 60h satisfies Φo < Φ < Φs. Here, Φo is the liquid level angle assuming that the slip ratio of the gas and liquid of the refrigerant is 1 and the gas-liquid interface is planar and horizontal, and Φs is the liquid level angle of the refrigerant in the header pipe. The flow path cross-sectional area of ​​the header flow path P1h is As [mm²] ２ If defined as ], then Φo is (-0.0408 × As + 74.124) × 0.62 and Φs is (-0.0408 × As + 74.124) × 1.2.

[0065] By the way, in the example in Figure 1, the heat exchanger 101 is defined as having two headers (upper header 61 and lower header 62), with the upper header 61 passing through the upper ends of the multiple flat tubes 10 and the lower header 62 passing through the lower ends of the multiple flat tubes 10. However, it may also be configured with only one header. Alternatively, both headers may be arranged front to back so as to pass through one end of the multiple flat tubes 10 in the axial direction. Furthermore, the heat exchanger 101 may have three or more headers.

[0066] Figure 24 is a longitudinal cross-sectional view showing a first modified example of the header in the heat exchanger 101 of Figure 3. As shown in Figure 24, the upper header 161 consists of three small-diameter headers 161a, 161b, and 161c that penetrate a plurality of flat tubes 10 in a first direction D1 and are arranged in the axial direction of the tubes (second direction D2) and in a direction perpendicular to the first direction D1 (third direction D3) in each of the plurality of flat tubes 10. Each small-diameter header 161a, 161b, and 161c has a cylindrical shape, and its outer diameter W2 is smaller than the outer diameter W1 of the upper header 61 in Figure 3. Each flat tube 10 has three circular header insertion holes 10h1a, 10h1b, and 10h1c into which the three small-diameter headers 161a, 161b, and 161c are inserted. Furthermore, the number of small-diameter headers 161a, 161b, and 161c arranged in the third direction D3 is not limited to three; it may be two, four or more.

[0067] Thus, by configuring the header (upper header 161) with multiple small-diameter headers 161a, 161b, and 161c, the opening diameters of the header insertion holes 10h1a, 10h1b, and 10h1c can be smaller compared to the case where a single header tube (upper header 61) is used, as shown in Figure 3. Therefore, the heat transfer area is increased in the longitudinal direction (second direction D2) of the flattened tube 10, and the heat exchange performance of the heat exchanger 101 is improved. Furthermore, by configuring the header (upper header 161) with multiple small-diameter headers 161a, 161b, and 161c, liquid unevenness is mitigated, distribution is improved, and heat exchange performance is enhanced.

[0068] Figure 25 is a longitudinal cross-sectional view showing a second modified example of the header in the heat exchanger 101 of Figure 3. As shown in Figure 25, the upper header is composed of a flattened header 261 whose cross-sectional shape perpendicular to the first direction D1 is flattened. In Figure 25, the cross-sectional shape of the flattened header 261 is oval. The flattened header 261 penetrates multiple flattened tubes 10 such that the longitudinal direction of its cross-section coincides with the direction perpendicular to the tube axis and the first direction D1 (third direction D3) in each of the multiple flattened tubes 10. In the longitudinal direction of the flattened tubes 10 (second direction D2), the outer diameter W3 of the flattened header 261 is smaller than the outer diameter W1 of the upper header 61 in Figure 3.

[0069] Thus, by configuring the header (upper header) with a flattened header 261, the opening width of the header insertion hole 10h1 in the second direction D2 can be smaller compared to the case where it is configured with a single header pipe (upper header 61) as shown in Figure 3. Therefore, as in the case of Figure 24, the heat transfer area in the longitudinal direction (second direction D2) of the flattened pipe 10 is increased in the case of Figure 25, and the heat exchange performance of the heat exchanger 101 is improved.

[0070] Figure 26 is a schematic external perspective view showing a first modified example of the flow path configuration in the heat exchanger 101 of Figure 1. Figure 27 is a longitudinal cross-sectional view of the heat exchanger 101 of Figure 26. Figure 28 is a partial longitudinal cross-sectional view showing the C-C cross-section of the heat exchanger 101 of Figure 27. As shown in Figures 26 to 28, by changing the arrangement of the two headers, a different refrigerant flow path can be configured than that in Figure 1.

[0071] In the heat exchanger 101 shown in Figures 26 to 28, two headers (first header 361 and second header 362) are provided in parallel, front to back, at the bottom of the heat exchanger 101. In Figure 26, the first header 361, to which the first pipe a is provided, is located at the rear, and the second header 362, to which the second pipe b is provided, is located at the front. Both the first pipe a and the second pipe b are provided on the lower left side of the heat exchanger 101. At the upper end of each header (first header 361, second header 362), for example, multiple communication holes 60h are provided to connect the internal space of the header with the internal space of the multiple flat pipes 10.

[0072] Furthermore, a first partition 30 is provided inside each flattened tube 10, extending in the longitudinal direction (second direction D2, up and down direction) of the flattened tube 10 and dividing the internal space of the tube wall 11 of the flattened tube 10 in the short direction (third direction D3, front and back direction) of the flattened tube 10. As shown in Figure 28, the upper end 30e of the first partition 30 is provided below the upper open end 10e of the flattened tube 10, thereby forming a return flow path P1at in the upper part of the internal space of the tube wall 11, through which the refrigerant can flow in the front and back direction (third direction D3). In other words, the heat transfer flow path P1a of the refrigerant inside the flattened tube 10 has an inverted U shape that includes the return flow path P1at.

[0073] As shown in Figure 27, the refrigerant flow path of the heat exchanger 101 is composed of a plurality of heat transfer flow paths P1a and two header flow paths P1h provided in parallel front to back at the bottom of the heat exchanger 101, each of which intersects with the plurality of heat transfer flow paths P1a.

[0074] In the heat exchanger 101 shown in Figures 26 to 28, the refrigerant first flows into a first header 361 that penetrates the lower rear side of the multiple flat tubes 10 in a left-right direction. As shown in Figure 27, the refrigerant that flows into the first header 361 flows from left to right through the header flow path P1h within the first header 361. In this process, the refrigerant is distributed to the multiple flat tubes 10 through multiple communication holes 60h provided in the first header 361 and flows into the heat transfer flow path P1a of each flat tube 10. As shown in Figure 28, in each heat transfer flow path P1a, the refrigerant flows upward along the rear side of the internal space of the tube wall 11, flows forward through a return flow path P1at at the upper part of the internal space of the tube wall 11, and then flows downward along the front side of the internal space of the tube wall 11. At this time, as shown in Figure 27, the refrigerant exchanges heat with the air flowing through the gaps between the pipe walls 11 of the flattened pipes 10 (i.e., the air passage P2) via the pipe walls 11. As shown in Figures 26 and 27, the refrigerant from the multiple heat transfer passages P1a flow into the header passage P1h in the second header 362, which penetrates the lower front side of the multiple flattened pipes 10, and merges in the header passage P1h. The refrigerant that has merged in the header passage P1h in the second header 362 flows out from the second pipe b on the left side to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c shown in Figure 2).

[0075] Note that the heat exchanger 101 shown in Figures 26 to 28 is just one example of the heat exchanger 101 of this disclosure, and the shape of the heat transfer flow path P1a, the presence, number and arrangement of the first partition 30 in the flattened pipe 10, and the arrangement of the first pipe a and second pipe b in the heat exchanger 101 can be changed as appropriate.

[0076] Figure 29 is a schematic external perspective view showing a second modified example of the flow path configuration in the heat exchanger 101 of Figure 1. In the heat exchanger 101 of Figure 29, two headers (first header 461 and second header 462) are provided at the lower and upper parts of the center in the front-to-back direction (third direction D3) of the heat exchanger 101. In Figure 29, the first header 461, to which the first pipe a and second pipe b are provided, is located on the lower side, and the second header 462 is located on the upper side. The first pipe a is provided at the left end of the first header 461, and the second pipe b is provided at the right end of the first header 461. Although not shown, the first header 461 and the second header 462 are each provided with a plurality of communication holes 60h.

[0077] The heat exchanger 101 in Figure 29 is equipped with a second partition 40 that divides the header flow path P1h in the direction of arrangement of the flattened tubes 10 (first direction D1). The second partition 40 blocks the flow of the refrigerant in the first direction D1 between adjacent heat transfer flow paths P1a. In the heat exchanger of Figure 29, one second partition 40 is provided in the first header 461 where the first pipe a and the second pipe b are provided. The second partition 40 may be provided in both the first header 461 and the second header 462, and the number of second partitions 40 provided in each header can be appropriately determined according to the desired flow path configuration.

[0078] Although not shown in the diagram, the refrigerant flow path of the heat exchanger 101 in Figure 29 is composed of a plurality of heat transfer flow paths P1a and two header flow paths P1h, which are provided in parallel at the lower and upper parts of the center in the front-to-back direction of the heat exchanger 101, and each intersects with the plurality of heat transfer flow paths P1a. However, the header flow path P1h of the first header 461 is divided by a second partition 40 into a left portion where the first pipe a is provided and a right portion where the second pipe b is provided. The heat exchanger 101 in Figure 29 does not have the first partition 30 shown in Figures 26 to 28, and the internal space of the pipe wall 11 is a single I-shaped heat transfer flow path P1a.

[0079] In the heat exchanger 101 shown in Figure 29, the refrigerant first flows into the left portion of the header flow path P1h in the first header 461, which penetrates the lower part of the multiple flat tubes 10, and flows from left to right in this left portion. In the process, the refrigerant is distributed and flows into the respective heat transfer flow paths P1a of some of the left-side flat tubes 10. The refrigerant that has flowed into each heat transfer flow path P1a of some of the left-side flat tubes 10 flows upward through the internal space of the tube wall 11, then merges in the header flow path P1h of the second header 462, which penetrates the upper part of the multiple flat tubes 10, and then flows to the right in the header flow path P1h, where it is distributed and flows into the respective heat transfer flow paths P1a of some of the right-side flat tubes 10, and flows downward. When the refrigerant flows upward through each heat transfer channel P1a of the flattened tubes 10 on the left side, and when it flows downward through each heat transfer channel P1a of the flattened tubes 10 on the right side, the refrigerant exchanges heat with the air flowing through the gaps between the tube walls 11 of the flattened tubes 10 (i.e., the air flow channel P2) via the tube walls 11. Subsequently, the refrigerant from each heat transfer channel P1a of the flattened tubes 10 on the right side flows into the right portion of the header channel P1h in the first header 461, merges in this right portion, and flows out from the second piping b to the outside of the heat exchanger 101 (for example, the expansion valve 105 of the refrigerant circuit 100c shown in Figure 8).

[0080] As described above, the heat exchanger 101 according to Embodiment 1 comprises a plurality of flat tubes 10 arranged in a first direction D1 intersecting the axial direction of the tube, with a fluid flowing inside the tube wall 11 and both ends in the axial direction of the tube (second direction D2) sealed, and one or more headers that penetrate and connect the plurality of flat tubes 10 in the first direction D1, with one or more header insertion holes 10h1, 10h2 formed in each of the plurality of flat tubes 10 that penetrate in the first direction D1 into which one or more headers are inserted, and one or more headers that have a communication hole 60h formed in which the inside of the header and the inside of the plurality of flat tubes 10 are connected, and each of the plurality of flat tubes 10 has a bent portion 10c formed by bending the plate material constituting the tube wall 11 at least one end in the longitudinal direction (third direction D3).

[0081] According to the heat exchanger 101 of Embodiment 1, each of the multiple flattened tubes 10 that constitute the fluid flow path has a bent portion 10c at least one end in the longitudinal direction (third direction D3) rather than a joined portion. Therefore, the number of joined portions can be reduced compared to conventional designs, and an increase in size and a decrease in strength can be suppressed.

[0082] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the multiple flattened tubes 10 extends in the tube axis direction (second direction D2) and has a joint portion 10d where plate material is joined to form a tube, and the joint portion 10d is formed at only one location in the circumferential direction.

[0083] According to the heat exchanger 101 of Embodiment 1, since the joint portion 10d, which is the part to be joined, is formed at only one location in the circumferential direction, the number of parts to be joined can be reduced compared to conventional designs, thereby suppressing an increase in size and a decrease in strength.

[0084] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the one or more header insertion holes 10h1 and 10h2 is formed at a position offset from the joint portion 10d.

[0085] According to the heat exchanger 101 of Embodiment 1, by forming the joint portion 10d in a position that does not overlap with the header insertion holes 10h1 and 10h2, a decrease in the strength of the flattened pipe 10 can be suppressed.

[0086] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the multiple flattened tubes 10 has a sealed region (sealed area) at at least one of its ends in the tube axis direction (second direction D2) that is longer in the longitudinal direction (third direction D3) than in the tube axis direction (second direction D2).

[0087] According to the heat exchanger 101 of Embodiment 1, the sealing region (region SR) at at least one end of the flattened tube 10 in the tube axis direction (second direction D2) is longer in the longitudinal direction (third direction D3) than in the tube axis direction (second direction D2), so the length of the flattened tube 10 in the tube axis direction (second direction D2) can be reduced.

[0088] Furthermore, in the heat exchanger 101 according to Embodiment 1, at least one of the ends of each of the multiple flattened tubes 10 in the axial direction (second direction D2) is crushed and sealed.

[0089] According to the heat exchanger 101 of Embodiment 1, by sealing the end of the flattened tube 10 in the axial direction (second direction D2) in this manner, no additional parts are required when sealing the end of the flattened tube 10 in the axial direction (second direction D2), and sealing can be done with a simple structure, thus reducing manufacturing costs.

[0090] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the multiple flattened tubes 10 is fitted with cap members 20, 20A, and 20B that cover the open end 10e at at least one of the ends in the tube axis direction (second direction D2).

[0091] According to the heat exchanger 101 of Embodiment 1, by providing such a sealing structure to the end of the flattened tube 10 in the axial direction (second direction D2), the end of the flattened tube 10 in the axial direction (second direction D2) can be firmly sealed by the cap members 20, 20A, and 20B, thereby more reliably preventing refrigerant leakage.

[0092] Furthermore, in the heat exchanger 101 according to Embodiment 1, the peripheral edges of one or more header insertion holes 10h1 and 10h2 in each of the multiple flat tubes 10 are joined at joints to maintain airtightness between the outer surface of the one or more headers and the interior of each of the multiple flat tubes 10.

[0093] According to the heat exchanger 101 of the first embodiment, the airtightness inside the multiple flattened tubes 10 can be maintained, thereby improving airtightness. Furthermore, since the header holds the multiple flattened tubes 10, the strength of the multiple flattened tubes 10 can be improved.

[0094] Furthermore, in the heat exchanger 101 according to Embodiment 1, the joint portion is a peripheral projection 12 that extends in the first direction D1 and is provided on the periphery of one or more header insertion holes 10h1, 10h2 in each of the multiple flattened tubes 10.

[0095] According to the heat exchanger 101 of Embodiment 1, the header is supported, and when assembling the multiple flat tubes 10 with the header, the header can be guided in the direction of insertion.

[0096] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the plurality of flattened tubes 10 has a first tube side wall portion 10a on one side in the first direction D1 and a second tube side wall portion 10b on the other side in the first direction D1, and each of the one or more header insertion holes 10h1, 10h2 is composed of a first hole ha provided in the first tube side wall portion 10a of the flattened tube 10 in which the one or more header insertion holes 10h1, 10h2 are formed and a second hole hb provided in the second tube side wall portion 10b, and the peripheral protrusion 12 is formed on the peripheral edge of the first hole ha in the first tube side wall portion 10a, and the first direction It is composed of a first peripheral projection 12a extending to one side in the direction D1, and a second peripheral projection 12b formed on the peripheral edge of the second hole hb in the second pipe side wall 10b and extending to the other side in the first direction D1. The first peripheral projection 12a and the second peripheral projection 12b each have inclined tapered portions 12at and 12bt on the base end side, and in the first direction D1, the width Wh of each communication hole 60h formed in each of the one or more headers is greater than the distance between the first pipe side wall 10a and the second pipe side wall 10b of each of the multiple flattened pipes 10.

[0097] According to the heat exchanger 101 of Embodiment 1, the first peripheral protrusion 12a and the second peripheral protrusion 12b each have tapered portions 12at and 12bt, respectively, which makes it possible to make the width Wh of each communication hole 60h of the header larger than the width W of the heat transfer flow path P1a in the first direction D1, thereby ensuring the amount of refrigerant distributed to each flattened tube 10.

[0098] Furthermore, in the heat exchanger 101 according to Embodiment 1, the joint portion is provided on the periphery of one or more header insertion holes 10h1, 10h2 in each of the plurality of flat tubes 10, and is a joint member 25 separate from the plurality of flat tubes 10, the joint member 25 has an outer diameter larger than the one or more header insertion holes 10h1, 10h2, and has a flat tube joint surface 25a that is joined to the flattened surface of the plurality of flat tubes 10, and a header joint surface 25b that is connected to the outer circumferential surface of one or more headers.

[0099] According to the heat exchanger 101 of Embodiment 1, there is no need to perform the processing necessary to form the peripheral protrusion 12 on the flattened tube 10, and it is sufficient to provide a joining member 25 that is separate from the flattened tube 10, thus simplifying the manufacturing process.

[0100] Furthermore, the heat exchanger 101 according to Embodiment 1 is equipped with a plurality of heat transfer fins 50 arranged between adjacent flattened tubes 10 in a first direction D1, the length of the plurality of heat transfer fins 50 in the first direction D1 is longer than the distance La in the first direction D1 between the joints of adjacent flattened tubes 10, and a portion of the outer circumferential surface of one or more headers is exposed to the outside.

[0101] According to the heat exchanger 101 of Embodiment 1, the heat transfer fins 50 are larger, which reduces airflow resistance and improves heat exchange performance. Furthermore, the joints of adjacent flat tubes 10 do not interfere with each other, a good joint can be formed, and the arrangement pitch of the flat tubes 10 can be freely designed.

[0102] Furthermore, in the heat exchanger 101 according to Embodiment 1, each of the one or more headers has a communication hole 60h formed for each of the multiple flattened tubes 10.

[0103] According to the heat exchanger 101 of Embodiment 1, by providing a communication hole 60h for one flat tube 10 in each header, even if the heat exchanger 101 is tilted or deformed, the refrigerant can be uniformly distributed from each header to each flat tube 10, thereby improving distribution performance.

[0104] Furthermore, in the heat exchanger 101 according to Embodiment 1, when the heat exchanger 101 is arranged such that the pipe axis direction (second direction D2) is vertical, each of the communication holes 60h in each of the one or more headers is provided such that Φ satisfies Φo < Φ < Φs, where Φ is the angle when the vertical downward direction of the center Ch of the header peripheral wall is defined as 0 degrees, Φo is the liquid level angle assuming that the slip ratio of the gas and liquid fluid is 1 and the gas-liquid interface is planar and horizontal, and Φs is the liquid level angle of the fluid inside the header peripheral wall, and the flow path cross-sectional area inside the header peripheral wall is As [mm²] ２When defined as ], Φo is (-0.0408 × As + 74.124) × 0.62 and Φs is (-0.0408 × As + 74.124) × 1.2.

[0105] According to the heat exchanger 101 of Embodiment 1, communication holes 60h are provided in the header peripheral wall at positions that tend to be near the liquid level, resulting in a nearly uniform ratio of liquid to gas distributed to each flat tube 10, improving the distribution performance by the header and thus improving the performance of the heat exchanger 101.

[0106] Furthermore, the air conditioning system 100 according to Embodiment 1 includes a compressor 102, the heat exchanger 101, the expansion valve 105, and the indoor heat exchanger 104, which are connected via piping, and are equipped with a fluid circuit (refrigerant circuit 100c) through which fluid circulates.

[0107] According to the air conditioning system 100 of Embodiment 1, the same effects as those of the heat exchanger 101 described above can be obtained.

[0108] 10 Flattened pipe, 10a First pipe side wall, 10b Second pipe side wall, 10c Bent section, 10d Joint section, 10e Open end, 10h1 Header insertion hole, 10h1a Header insertion hole, 10h1b Header insertion hole, 10h1c Header insertion hole, 10h2 Header insertion hole, 11 Pipe wall, 12 Peripheral protrusion, 12a First peripheral protrusion, 12ae Tip section, 12at Tapered section, 12b Second peripheral protrusion, 12be Tip section, 12bt Tapered section, 20 Cap member, 20A Cap member, 20B Cap member, 20a Recess, 25 Joining member 25a Flattened pipe joining surface, 25b Header joining surface, 30 First partition, 30e Upper end, 40 Second partition, 50 Heat transfer fin, 60h Communication hole, 61 Upper header, 62 Lower header, 100 Air conditioning unit, 100A Outdoor unit unit, 100B Indoor unit unit, 100c Refrigerant circuit, 101 Heat exchanger, 102 Compressor, 103 Four-way valve, 104 Indoor heat exchanger, 105 Expansion valve, 106 Indoor fan, 107 Outdoor fan, 161 Upper header, 161a Small diameter header, 161b Small diameter header, 161c Small diameter header, 261 Flattened header, 361 First header, 362 Second header, 461 First header, 462 Second header, Ax Pipe axis, Ch Center, D1 First direction, D2 Second direction, D3 Third direction, La Spacing, Lb Spacing, Lh Spacing, Lp Pipe pitch, P1a Heat transfer flow path, P1at Return flow path, P1h Header flow path, P2 flow path, SR area, W width, W1 outer diameter, W2 outer diameter, W3 outer diameter, Wh width, a first pipe, b second pipe, d1 outer diameter, d2 diameter, d3 inner diameter, d4 outer diameter, ha first hole, hb second hole, Φ angle.

Claims

1. A heat exchanger comprising: a plurality of flattened tubes arranged in a first direction intersecting the axial direction of the tubes, with a fluid flowing inside the tube wall and both ends in the axial direction of the tubes sealed; and one or more headers that penetrate and connect the plurality of flattened tubes in the first direction, wherein each of the plurality of flattened tubes has one or more header insertion holes that penetrate in the first direction into which the one or more headers are inserted; each of the one or more headers has a communication hole that connects its interior to the interior of the plurality of flattened tubes; and each of the plurality of flattened tubes has a bent portion formed by bending the plate material constituting the tube wall at at least one end in the longitudinal direction.

2. The heat exchanger according to claim 1, wherein each of the plurality of flattened tubes extends in the axial direction of the tube and has a joint portion where the plate material is joined to form a tube, and the joint portion is formed at only one location in the circumferential direction.

3. The heat exchanger according to claim 2, wherein each of the one or more header insertion holes is formed at a position offset from the joint.

4. The heat exchanger according to claim 2 or 3, wherein each of the plurality of flattened tubes has a sealed region at at least one of its ends in the axial direction of the tube, and the sealed region is longer in the longitudinal direction than in the axial direction of the tube.

5. The heat exchanger according to claim 4, wherein each of the plurality of flattened tubes has at least one of its ends in the axial direction of the tube flattened tubes crushed and sealed.

6. The heat exchanger according to claim 4 or 5, wherein each of the plurality of flattened tubes is fitted with a cap member covering the open end at at least one of the ends in the axial direction of the tube.

7. The heat exchanger according to any one of claims 1 to 6, wherein in each of the plurality of flattened tubes, the peripheral edge of each of the one or more header insertion holes is joined at a joint to maintain airtightness between the outer surface of each of the one or more headers and the interior of each of the plurality of flattened tubes.

8. The heat exchanger according to claim 7, wherein the joint portion is provided on the periphery of each of the one or more header insertion holes in each of the plurality of flattened tubes and is a peripheral projection extending in the first direction.

9. Each of the plurality of flattened tubes has a first tube side wall portion on one side in the first direction and a second tube side wall portion on the other side in the first direction, and each of the one or more header insertion holes is composed of a first hole provided in the first tube side wall portion and a second hole provided in the second tube side wall portion of the flattened tube in which the one or more header insertion holes are formed, and the peripheral projection is composed of a first peripheral projection formed on the periphery of the first hole in the first tube side wall portion and extending to the one side in the first direction, and a second peripheral projection formed on the periphery of the second hole in the second tube side wall portion and extending to the other side in the first direction, and the first peripheral projection and the second peripheral projection each have an inclined tapered portion on the base end side, The heat exchanger according to claim 8, wherein, in the first direction, the width of each of the communication holes formed in each of the one or more headers is greater than the distance between the first pipe side wall portion and the second pipe side wall portion of each of the plurality of flattened pipes.

10. The heat exchanger according to claim 7, wherein the joint is provided on the periphery of each of the one or more header insertion holes in each of the plurality of flat tubes, and is a joint member separate from the plurality of flat tubes, the joint member has an outer diameter larger than the one or more header insertion holes, and has a flat tube joint surface that is joined to the flattened surface of the plurality of flat tubes, and a header joint surface that is joined to the outer circumferential surface of the one or more headers.

11. A heat exchanger according to any one of claims 7 to 10, comprising a plurality of heat transfer fins arranged between adjacent flat tubes in the first direction, wherein the length of the plurality of heat transfer fins in the first direction is longer than the length of the joint in the first direction, and a portion of the outer circumferential surface of each of the one or more headers is exposed to the outside.

12. The heat exchanger according to any one of claims 1 to 11, wherein each of the one or more headers has the communication hole formed for each of the plurality of flattened tubes.

13. In a state in which the heat exchanger is arranged such that the direction of the pipe axis is vertical, each of the communication holes in each of the one or more headers is provided such that Φ satisfies Φo < Φ < Φs, where Φ is defined as the angle when the vertical downward direction of the center of the header peripheral wall is 0 degrees, Φo is the liquid level angle assuming that the slip ratio of the gas and liquid of the fluid is 1 and the gas-liquid interface is planar and horizontal, and Φs is the liquid level angle of the fluid within the header peripheral wall, and the flow path cross-sectional area within the header peripheral wall is As [mm²] ２ The heat exchanger according to any one of claims 1 to 12, wherein, when defined as ], Φo is (-0.0408 × As + 74.124) × 0.62 and Φs is (-0.0408 × As + 74.124) × 1.

2.

14. An air conditioning system comprising a compressor, a heat exchanger according to any one of claims 1 to 13, an expansion valve, and an indoor heat exchanger, connected via piping, and comprising a fluid circuit through which the fluid circulates.

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