JP7483062B2 - Heat exchanger and refrigeration cycle device equipped with same - Google Patents

Description

The present disclosure relates to a heat exchanger and a refrigeration cycle device equipped with the same.

One type of heat exchanger used in air conditioners is a heat exchanger that uses flattened heat transfer tubes with multiple flow paths through which the refrigerant flows. When operating this type of heat exchanger as an evaporator, it is required to pass more refrigerant through the flow paths located on the windward side in order to improve heat transfer performance. For example, Patent Document 1 proposes a heat exchanger equipped with flattened heat transfer tubes in which the flow paths located on the windward side are wider than the flow paths located on the leeward side.

JP 2015-90219 A

Flat heat transfer tubes are manufactured, for example, by extruding a material such as aluminum. In flat heat transfer tubes in which the flow passages on the windward side are wider than the flow passages on the leeward side, for example, it can be difficult to manufacture the desired flat heat transfer tube due to an asymmetric cross-sectional shape. There is a demand for heat exchangers to improve manufacturability while maintaining heat transfer performance.

The present disclosure has been made as part of such development, and one objective is to provide a heat exchanger that improves manufacturability while ensuring heat transfer performance, and another objective is to provide a refrigeration cycle device that employs such a heat exchanger.

The heat exchanger according to the present disclosure includes a flattened heat transfer tube, a header, and a heat dissipation fin. The flattened heat transfer tube has a first side portion and a second side portion separated by a width in a first direction, and extends in a second direction intersecting the first direction. The flattened heat transfer tube has a plurality of flow paths extending in the second direction, and is arranged at intervals in the first direction. The header has an opening, and the flattened heat transfer tube is connected to the opening. The flattened heat transfer tube includes a main body portion and a connection portion. The main body portion is attached to the heat dissipation fin. The connection portion has an opening end surface where each of the plurality of flow paths is open, and is inserted into the opening of the header and connected to the header. In the main body portion, each of the plurality of flow paths has a first flow path cross-sectional area. In the connection portion, only the first side portion is tapered in such a manner that the width is reduced as it approaches the opening end surface. At the open end surface, a first open end of a first flow passage, among the plurality of flow passages, closest to the tapered first side portion has a second flow passage cross-sectional area smaller than the first flow passage cross-sectional area.
Another heat exchanger according to the present disclosure includes a flattened heat transfer tube, a header, and a heat dissipation fin. The flattened heat transfer tube has a first side portion and a second side portion separated by a width in a first direction, and extends in a second direction intersecting the first direction. The flattened heat transfer tube has a plurality of flow paths extending in the second direction, and is arranged at intervals in the first direction. The header has an opening, and the flattened heat transfer tube is connected to the opening. The flattened heat transfer tube includes a main body portion and a connection portion. The main body portion is attached to the heat dissipation fin. The connection portion has an opening end surface where each of the plurality of flow paths is open, and is inserted into the opening of the header and connected to the header. In the main body portion, each of the plurality of flow paths has a first flow path cross-sectional area. In the connection portion, the first side portion is formed in a tapered shape such that the width is reduced as it approaches the opening end surface. At the open end surface, a first open end of a first flow passage, among the plurality of flow passages, closest to the tapered first side portion has a second flow passage cross-sectional area smaller than the first flow passage cross-sectional area. At the connection portion, the second side portion is tapered such that its width decreases as it approaches the open end surface. At the open end surface, a second open end of a second flow passage, among the plurality of flow passages arranged along the first direction, closest to the tapered second side portion has a third flow passage cross-sectional area smaller than the first flow passage cross-sectional area and larger than the second flow passage cross-sectional area. At the connection portion, the first side portion is tapered more inward in the width direction of the flat heat transfer tube than the second side portion.

The refrigeration cycle device of the present disclosure is equipped with the above-mentioned heat exchanger.

According to the heat exchanger of the present disclosure, the flat heat transfer tube includes a main body and a connecting portion. The flat heat transfer tube has a plurality of flow paths arranged at intervals from each other. The flat heat transfer tube has a first side portion and a second side portion separated by a width. The connecting portion connected to the opening of the header has an opening end surface on which the plurality of flow paths are each open. In the connecting portion, the first side portion is tapered in such a manner that the width is reduced as it approaches the opening end surface. This allows the connecting portion to be easily inserted into the opening of the header, which contributes to improving manufacturability. In addition, in the opening end surface, the first opening end of the first flow path closest to the first side portion has a second flow path cross-sectional area smaller than the first flow path cross-sectional area. This allows more refrigerant to flow in the flow path located in the area with high heat load, thereby ensuring heat transfer performance.

According to the refrigeration cycle device of the present disclosure, by being equipped with the above-mentioned heat exchanger, it is possible to improve manufacturability while ensuring heat transfer performance.

1 is a diagram showing a refrigerant circuit of a refrigeration cycle device including an outdoor heat exchanger according to each embodiment. FIG. 2 is a perspective view illustrating an example of an outdoor heat exchanger according to each embodiment. 4 is a top view, including a partial cross section, showing the structure of a portion where a flat heat transfer tube is connected to a header in the outdoor heat exchanger according to the first embodiment. FIG. 4 is a cross-sectional view taken along line IV-IV in FIG. 3 in the embodiment. FIG. 4 is a front view showing an open end surface at a connection portion of the flat heat transfer tube in the embodiment. FIG. 4 is a diagram showing an example of a flowchart of a method for manufacturing the outdoor heat exchanger in the embodiment. FIG. 4 is a partial top view showing a step of a manufacturing method of the outdoor heat exchanger in the embodiment. 8 is a top view including a partial cross section showing a step performed after the step shown in FIG. 7 in the embodiment. FIG. 5A to 5C are diagrams for explaining the operation and effect of the outdoor heat exchanger in the embodiment. 11 is a top view, partially including a cross section, showing the structure of a portion where a flat heat transfer tube is connected to a header in an outdoor heat exchanger according to a second embodiment. FIG. FIG. 4 is a front view showing an open end surface at a connection portion of the flat heat transfer tube in the embodiment. FIG. 4 is a partial top view showing a step of a manufacturing method of the outdoor heat exchanger in the embodiment. 13 is a top view, partially including a cross section, showing the structure of a portion where a flat heat transfer tube is connected to a header in an outdoor heat exchanger according to embodiment 3. FIG. FIG. 4 is a front view showing an open end surface at a connection portion of the flat heat transfer tube in the embodiment. FIG. 4 is a partial top view showing a step of a manufacturing method of the outdoor heat exchanger in the embodiment. 16 is a partial top view including a partial cross section, showing a step performed after the step shown in FIG. 15 in the embodiment. FIG. 13 is a top view, including a partial cross section, showing the structure of a portion where a flat heat transfer tube is connected to a header in an outdoor heat exchanger according to embodiment 4. FIG. FIG. 4 is a front view showing an open end surface at a connection portion of the flat heat transfer tube in the embodiment. FIG. 4 is a partial top view showing a step of a manufacturing method of the outdoor heat exchanger in the embodiment. 11 is a perspective view showing another example of the outdoor heat exchanger according to the embodiments. FIG.

First, an example of a refrigerant circuit of a refrigeration cycle device equipped with a heat exchanger (outdoor heat exchanger) according to each embodiment will be described. As shown in Fig. 1, the refrigeration cycle device 1 includes a compressor 3, an indoor heat exchanger 5, a fan 7, an expansion valve 9, an outdoor heat exchanger 11, a propeller fan 13, a four-way valve 15, and refrigerant piping 17 connecting these. The structure of the outdoor heat exchanger 11 will be described in detail in each embodiment.

Next, the operation of the above-mentioned refrigeration cycle device 1 will be described first in the case of heating operation. The flow of refrigerant in the case of heating operation is shown by a solid line. By driving the compressor 3, high-temperature, high-pressure gas refrigerant is discharged from the compressor 3. The discharged high-temperature, high-pressure gas refrigerant (single phase) flows into the indoor heat exchanger 5 via the four-way valve 15.

In the indoor heat exchanger 5, heat exchange takes place between the gas refrigerant that has flowed in and the air sent in by the fan 7. The high-temperature, high-pressure gas refrigerant condenses into high-pressure liquid refrigerant (single phase). The air that has undergone heat exchange is sent out from the indoor heat exchanger 5 into the room, heating the room. The high-pressure liquid refrigerant sent out from the indoor heat exchanger 5 is converted by the expansion valve 9 into a two-phase refrigerant consisting of low-pressure gas refrigerant and liquid refrigerant.

The two-phase refrigerant flows into the outdoor heat exchanger 11. The outdoor heat exchanger 11 functions as an evaporator. In the outdoor heat exchanger 11, heat exchange takes place between the two-phase refrigerant that has flowed in and the air supplied by the propeller fan 13. Of the two-phase refrigerant, the liquid refrigerant evaporates and becomes low-pressure gas refrigerant (single phase). At this time, more refrigerant flows into the refrigerant flow path located on the upwind side than into the refrigerant flow path located on the downwind side. The low-pressure gas refrigerant is sent out from the outdoor heat exchanger 11.

The low-pressure gas refrigerant sent out from the outdoor heat exchanger 11 flows into the compressor 3 through the four-way valve 15. The low-pressure gas refrigerant that flows into the compressor 3 is compressed to become high-temperature, high-pressure gas refrigerant, which is then discharged again from the compressor 3. This cycle is then repeated.

Next, the cooling operation will be described. By driving the compressor 3, high-temperature, high-pressure gas refrigerant is discharged from the compressor 3. The discharged high-temperature, high-pressure gas refrigerant (single phase) flows into the outdoor heat exchanger 11 via the four-way valve 15. The outdoor heat exchanger 11 functions as a condenser. In the outdoor heat exchanger 11, heat exchange takes place between the refrigerant that has flowed in and air supplied by the propeller fan 13. The high-temperature, high-pressure gas refrigerant condenses to become high-pressure liquid refrigerant (single phase).

The high-pressure liquid refrigerant sent out from the outdoor heat exchanger 11 is converted by the expansion valve 9 into a two-phase refrigerant consisting of low-pressure gas refrigerant and liquid refrigerant. The two-phase refrigerant flows into the indoor heat exchanger 5. In the indoor heat exchanger 5, heat exchange takes place between the two-phase refrigerant that has flowed in and the air sent into the indoor heat exchanger 5 by the fan 7. The two-phase refrigerant becomes a low-pressure gas refrigerant (single phase) as the liquid refrigerant evaporates. The air that has undergone heat exchange is sent out from the indoor heat exchanger 5 into the room to cool the room.

The low-pressure gas refrigerant sent out from the indoor heat exchanger 5 flows into the compressor 3 through the four-way valve 15. The low-pressure gas refrigerant that flows into the compressor 3 is compressed to become a high-temperature, high-pressure gas refrigerant, which is then discharged from the compressor 3 again. This cycle is repeated below. Next, the structure of the outdoor heat exchanger 11 according to each embodiment will be described. For convenience of explanation, each embodiment will be described using the X-axis and Y-axis.

Embodiment 1.
An example of an outdoor heat exchanger as a heat exchanger according to the first embodiment will be described. As shown in Fig. 2, an outdoor heat exchanger 11 including flat heat transfer tubes 21 and heat dissipation fins 41 and a header 31 are housed in a housing 10 of the outdoor unit. Here, a single-row type outdoor heat exchanger 11 is arranged. Also housed in the housing 10 are a propeller fan 13 and a compressor 3 (not shown), etc. Driving the propeller fan 13 (not shown) causes air to flow in the housing 10 in the direction indicated by the arrow Y1.

As shown in Figure 3, the flat heat transfer tube 21 in the outdoor heat exchanger 11 has a main body portion 23 and a connection portion 25. The flat heat transfer tube 21 has a width in the Y-axis direction as a first direction, and extends in the X-axis direction as a second direction. In the flat heat transfer tube 21, a plurality of flow paths 27 each extending in the X-axis direction are arranged at intervals from each other in the Y-axis direction (see Figure 4).

The flat heat transfer tube 21 has a first side 29a and a second side 29b separated by a width. Here, the first side 29a is located on the downwind side, and the second side 29b is located on the upwind side. A heat dissipation fin 41 is attached to the main body 23.

The connection portion 25 has an opening end surface 26 on which the opening ends 28 (see FIG. 5) of each of the multiple flow paths 27 are located. Here, the opening end surface 26 is located along the Y-axis direction. The connection portion 25 is connected to the header 31 in a manner such that it is inserted into an opening 33 formed in the header 31. The first side portion 29a and the second side portion 29b of the connection portion 25 are in contact with the opening inner wall surface 34 of the opening 33. As shown in FIG. 4, in the main body portion 23, each of the multiple flow paths 27 has a first flow path cross-sectional area S1. As described below, when manufacturing the flat heat transfer tube 21, first, a molded body that becomes the main body portion 23 is manufactured.

3 and 5, at the connection portion 25, the flat heat transfer tube 21 is subjected to processing (tube shrinking) to shrink it in the width direction (Y-axis direction). At the connection portion 25, the first side portion 29a is tapered such that the width shrinks as it approaches the opening end surface 26. At the opening end surface 26, among the multiple flow paths 27 arranged along the Y-axis direction, the first opening end 28a of the first flow path 27a closest to the first side portion 29a is narrowed in the Y-axis direction to correspond to the tapered first side portion 29a.

Therefore, the first open end 28a of the first flow path 27a has a second flow path cross-sectional area S2 smaller than the first flow path cross-sectional area S1 of the open end 28 of the other flow path 27. That is, the first open end 28a of the first flow path 27a closest to the first side portion 29a has a second flow path cross-sectional area S2 smaller than the first flow path cross-sectional area S1 of the open end 28 of the other flow path 27. The outdoor heat exchanger 11 according to the first embodiment is configured as described above.

Next, an example of a manufacturing method for the above-mentioned outdoor heat exchanger 11 will be described based on a flowchart. As shown in Figure 6, first, in step T1, material to become the flat heat transfer tube is prepared. Next, in step T2, the material is fed into an extrusion molding machine. Next, in step T3, the material fed into the extrusion molding machine is extruded to produce a molded body 20 (see Figure 7) to become the flat heat transfer tube.

At this time, each of the multiple flow paths 27 (see FIG. 4) is extruded to have a first flow path cross-sectional area S1, so that the cross-sectional shape of the molded body 20 (see FIG. 7) is line-symmetrical with respect to the center line in the width direction, as shown in the cross-sectional shape of the main body 23 (see FIG. 4). This allows the material to be extruded uniformly, making it possible to produce a molded body without voids, for example.

Next, in step T4, the molded body 20 (see FIG. 7) is cut and shrunk. As shown in FIG. 7, the molded body 20 is cut along the Y-axis direction. The cut surfaces of the cut molded body 20 form opening end faces 26, and each of the multiple flow paths 27 (see FIG. 4, etc.) is open.

At this time, the molded body 20 is cut and the molded body 20 is shrunk. That is, in a manner in which the width of the molded body 20 is reduced as it approaches the opening end face 26, the first side portion 29a of the molded body 20 is formed into a tapered shape by applying pressure (see arrow P1) to the first side portion 29a of the molded body 20 using, for example, a plate material (not shown) or the like.

By forming the tapered first side portion 29a, the first open end 28a of the first flow passage 27a closest to the first side portion 29a is narrowed in the Y-axis direction at the open end surface 26 (see FIG. 5). As a result, the first open end 28a of the first flow passage 27a closest to the first side portion 29a has a second flow passage cross-sectional area S2 smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passage 27. In this way, the flat heat transfer tube 21 including the main body portion 23 and the connection portion 25 is completed (step T5).

Next, in step T6, the flat heat transfer tube 21 is connected to the header 31 (see FIG. 8). As shown in FIG. 8, the connection portion 25 of the flat heat transfer tube 21 is inserted into the opening 33 provided in the header 31 as shown by the arrow P3, and the first side portion 29a and the second side portion 29b are brought into contact with the opening inner wall surface 34 of the opening 33.

At this time, the first side portion 29a is tapered, which makes it easier to insert into the opening 33 of the header 31. In addition, the length to which the connection portion 25 is inserted into the header 31 is uniquely defined, which makes it possible to prevent the connection portion 25 from being inserted, for example, more than necessary into the opening 33 of the header 31. In this way, the installation of the flat heat transfer tube 21 to the header 31 is completed, and the main portion of the outdoor heat exchanger 11 is completed.

According to the above-mentioned outdoor heat exchanger 11, first, when manufacturing the molded body that will become the flat heat transfer tube 21, a molded body having a cross-sectional shape that is line-symmetrical with respect to the center line in the width direction is molded as shown in the cross-sectional shape of the main body 23 (see FIG. 4). This allows the material to be extruded uniformly, and for example, a molded body without voids can be manufactured, which contributes to improving the manufacturability of the outdoor heat exchanger 11.

Next, in the flat heat transfer tube 21 manufactured from the molded body, the tapered first side portion 29a is formed, which improves manufacturability while ensuring heat transfer performance. This will be explained.

2, in the outdoor heat exchanger 11 of the refrigeration cycle device 1, heat exchange occurs between the air sent to the outdoor heat exchanger 11 (see arrow Y1) and the refrigerant flowing through the flat heat transfer tubes 21. When the outdoor heat exchanger 11 functions as an evaporator, the air sent to the outdoor heat exchanger 11 exchanges heat with the refrigerant flowing through the flat heat transfer tubes 21, and the temperature of the air decreases from upwind to downwind.

That is, as shown in Figure 9 (middle), the thermal load decreases as the ventilation distance that the air flows from upwind to downwind increases. In areas (ranges) with high thermal load, heat exchange between the air and the refrigerant actively takes place. For this reason, when functioning as an evaporator, if the refrigerant is completely gasified by heat exchange with the air, the heat transfer performance cannot be improved.

9 (top), the cut portion of the molded body 20 that will become the connection portion 25 of the flat heat transfer tube 21 is processed (contracted) for the portion that will become the main body of the flat heat transfer tube 21 so that the flow path of the refrigerant flowing on the windward side is greater than the flow rate of the refrigerant flowing on the leeward side. That is, the first side portion 29a is processed (contracted) to be tapered such that the width is reduced (from width W1 to width W2) as it approaches the opening end surface 26.

Therefore, in the connection portion 25 of the flat heat transfer tube 21, the first open end 28a of the first flow passage 27a closest to the first side portion 29a located on the leeward side is narrowed in the Y-axis direction to correspond to the tapered first side portion 29a. As a result, the first open end 28a has a second flow passage cross-sectional area S2 smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passage 27.

By making the second flow passage cross-sectional area S2 of the first opening end 28a of the first flow passage 27a located on the leeward side smaller than the first flow passage cross-sectional area S1 of the opening end 28 of the other flow passages 27, as shown in Figure 9 (lower), the refrigerant does not flow easily through the first flow passage 27a, and more refrigerant flows through the flow passages 27 located on the windward side, etc., where the heat load is high, and the refrigerant is prevented from being completely gasified. As a result, the heat transfer performance of the outdoor heat exchanger 11 can be ensured.

Furthermore, in the above-described outdoor heat exchanger 11, the first side portion 29a of the connection portion 25 of the flat heat transfer tube 21 connected to the header 31 is formed in a tapered shape, which makes it easier to insert the flat heat transfer tube 21 into the opening 33 formed in the header 31. This contributes to improving the manufacturability of the outdoor heat exchanger 11.

In addition, the tapered first side portion 29a of the connection portion 25 contacts the inner wall surface 34 of the opening 33, which uniquely defines the length to which the connection portion 25 (flat heat transfer tube 21) is inserted into the header 31. This makes it possible to prevent the connection portion 25 from being inserted, for example, into the opening 33 of the header 31 more than necessary. As a result, this contributes to stabilizing the flow of refrigerant in the header 31.

Embodiment 2.
An example of an outdoor heat exchanger as a heat exchanger according to embodiment 2 will be described. As shown in Fig. 10 and Fig. 11, the open end surface 26 of the flat heat transfer tube 21 is located along a third direction inclined with respect to the Y-axis direction from the first side portion 29a to the second side portion 29b in a manner approaching the main body portion 23.

At the connection 25 of the flat heat transfer tube 21, the first side portion 29a is tapered such that its width decreases as it approaches the open end face 26. The first open end 28a of the first flow passage 27a closest to the first side portion 29a has a second flow passage cross-sectional area S2 that is smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passage 27.

Other than this, the configuration is similar to that of the outdoor heat exchanger 11 shown in Figures 3 to 5, so the same components are given the same symbols and their descriptions will not be repeated unless necessary.

Next, an example of a method for manufacturing the above-mentioned outdoor heat exchanger 11 will be described. After going through steps similar to those shown in steps T1, T2, and T3 in FIG. 6, the molded body is cut and shrunk (step T4).

As shown in Figure 12, here, the molded body 20 is cut along a direction inclined with respect to the Y-axis direction. The cut surface of the cut molded body 20 forms an opening end surface 26, with each of the multiple flow paths 27 (see Figure 11) opening. At this time, the molded body 20 is contracted while being cut. That is, a tapered first side portion 29a of the molded body 20 is formed by applying pressure (see arrow P1) to the first side portion 29a of the molded body 20, for example, by a plate material (not shown) or the like, in such a manner that the width of the molded body 20 is reduced as it approaches the opening end surface 26.

By forming the tapered first side portion 29a, the first open end 28a of the first flow passage 27a closest to the first side portion 29a among the multiple flow passages 27 has a second flow passage cross-sectional area S2 smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passages 27 at the open end surface 26. In this way, the flat heat transfer tube 21 including the main body portion 23 and the connection portion 25 is completed (step T5). After that, through a process similar to step T6, the flat heat transfer tube 21 is attached to the header 31 and the main part of the outdoor heat exchanger 11 is completed.

According to the above-mentioned outdoor heat exchanger 11, in addition to the effects of the outdoor heat exchanger 11 described in embodiment 1, the following effects are obtained.

In the connection portion 25 of the flat heat transfer tube 21 of the outdoor heat exchanger 11 described above, the opening end face 26 is positioned along a direction inclined with respect to the Y-axis direction in such a manner as to approach the main body portion 23 from the first side portion 29a located on the downwind side toward the second side portion 29b located on the upwind side.

Therefore, the length of the second flow path 27b located on the leeward side is longer than the length of the first flow path 27a located on the windward side. As a result, the flow path resistance (friction resistance) of the second flow path 27b located on the leeward side is higher than the flow path resistance (friction resistance) of the first flow path 27a located on the windward side, making it easier for the refrigerant to flow through the second flow path 27b located on the windward side.

Therefore, by forming the first side portion 29a in a tapered shape, the refrigerant is less likely to flow through the first flow passage 27a located on the downwind side, and more refrigerant flows through the flow passage 27 located on the upwind side where the heat load is high. As a result, the heat transfer performance of the outdoor heat exchanger 11 can be improved.

Embodiment 3.
A description will be given of an example of an outdoor heat exchanger as a heat exchanger according to embodiment 3. As shown in Fig. 13 and Fig. 14, the open end surface 26 of the flat heat transfer tube 21 is positioned along the Y-axis direction.

At the connection 25 of the flat heat transfer tube 21, the first side portion 29a is tapered such that its width decreases as it approaches the open end surface 26. The first open end 28a of the first flow passage 27a closest to the first side portion 29a has a second flow passage cross-sectional area S2 that is smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passage 27.

Furthermore, in the connection portion 25, the second side portion 29b is tapered such that its width decreases as it approaches the open end surface 26. The second open end 28b of the second flow path 27b closest to the second side portion 29b has a third flow path cross-sectional area S3 that is smaller than the first flow path cross-sectional area S1 of the open end 28 of the other flow path 27 and larger than the second flow path cross-sectional area S2.

Other than this, the configuration is similar to that of the outdoor heat exchanger 11 shown in Figures 3 to 5, so the same components are given the same symbols and their descriptions will not be repeated unless necessary.

Next, an example of a method for manufacturing the above-mentioned outdoor heat exchanger 11 will be described. After going through steps similar to those shown in steps T1, T2, and T3 in FIG. 6, the molded body is cut and shrunk (step T4).

As shown in Figure 15, the molded body 20 is cut along the Y-axis direction. The cut surfaces of the cut molded body 20 form the opening end faces 26, with each of the multiple flow paths 27 (see Figure 14) opening. At this time, as the molded body 20 is cut, a tapered first side portion 29a and a tapered second side portion 29b are formed in both the first side portion 29a and the second side portion 29b of the molded body 20 in such a manner that the width of the molded body 20 decreases as it approaches the opening end face 26.

The tapered first side portion 29a is formed by applying pressure (pressure A: see arrow P1). The tapered second side portion 29b is formed by applying a pressure (pressure B: see arrow P2) lower than pressure A.

By making the relationship of the pressures for forming the tapered shape such that pressure A is greater than pressure B, the length narrowed in the Y-axis direction at the second opening end 28b of the second flow path 27b closest to the second side portion 29b at the opening end face 26 is shorter than the length narrowed at the first opening end 28a of the first flow path 27a closest to the first side portion 29a.

14, the second open end 28b of the second flow passage 27b is formed to have a third flow passage cross-sectional area S3 larger than the second flow passage cross-sectional area S2 of the first open end 28a of the first flow passage 27a. In this way, the flat heat transfer tube 21 including the main body 23 and the connection portion 25 is completed (step T5).

Next, in step T6, the flat heat transfer tube 21 is connected to the header 31 (see FIG. 16). As shown in FIG. 16, the connection portion 25 of the flat heat transfer tube 21 is inserted into the opening 33 provided in the header 31 as shown by the arrow P3, and the first side portion 29a and the second side portion 29b are brought into contact with the opening inner wall surface 34 of the opening 33.

At this time, because both the first side portion 29a and the second side portion 29b are tapered, it is easy to insert the connection portion 25 into the opening 33 of the header 31. In addition, the length to which the connection portion 25 is inserted into the header 31 is uniquely defined, and it is possible to prevent the connection portion 25 from being inserted, for example, more than necessary into the opening 33 of the header 31. In this way, the installation of the flat heat transfer tube 21 into the header 31 is completed, and the main part of the outdoor heat exchanger 11 is completed.

According to the above-mentioned outdoor heat exchanger 11, in addition to the effects of the outdoor heat exchanger 11 described in embodiment 1, the following effects are obtained.

In the connection portion 25 of the flat heat transfer tube 21 of the above-mentioned outdoor heat exchanger 11, both the first side portion 29a and the second side portion 29b are formed in a tapered shape. This makes it easier to insert the connection portion 25 of the flat heat transfer tube 21 into the opening 33 formed in the header 31 when connecting the connection portion 25 of the flat heat transfer tube 21 to the header 31, compared to when only the first side portion 29a is formed in a tapered shape. As a result, this can contribute to improving the manufacturability of the outdoor heat exchanger 11.

In addition, the tapered first side portion 29a and the tapered second side portion 29b of the connection portion 25 contact the inner wall surface 34 of the opening 33, so that the length to which the connection portion 25 (flat heat transfer tube 21) is inserted into the header 31 is more reliably determined. This makes it possible to prevent the connection portion 25 from being inserted into the opening 33 of the header 31 more than necessary. As a result, it is possible to contribute to stabilizing the flow of the refrigerant in the header 31.

Furthermore, at the opening end face 26 of the connection portion 25, the second opening end 28b of the second flow path 27b closest to the second side portion 29b has a third flow path cross-sectional area S3 that is smaller than the first flow path cross-sectional area S1 of the opening end 28 of the other flow path 27 and larger than the second flow path cross-sectional area S2.

As a result, for the second flow passage 27b located on the windward side where a larger amount of refrigerant is required to flow, the tapered second side portion 29b on the windward side can be formed to minimize the difficulty in the refrigerant flowing through the second flow passage 27b. As a result, the heat transfer performance of the outdoor heat exchanger 11 can be maintained.

Embodiment 4.
An example of an outdoor heat exchanger as a heat exchanger according to embodiment 4 will be described. As shown in Fig. 17 and Fig. 18, the open end surface 26 of the flat heat transfer tube 21 is located along a third direction inclined with respect to the Y-axis direction in a manner approaching the main body 23 from the first side portion 29a toward the second side portion 29b.

At the connection 25 of the flat heat transfer tube 21, the first side portion 29a is tapered such that its width decreases as it approaches the open end surface 26. The first open end 28a of the first flow passage 27a closest to the first side portion 29a has a second flow passage cross-sectional area S2 that is smaller than the first flow passage cross-sectional area S1 of the open end 28 of the other flow passage 27.

The second side portion 29b is tapered such that its width decreases as it approaches the opening end surface 26. The second opening end 28b of the second flow path 27b closest to the second side portion 29b has a third flow path cross-sectional area S3 that is smaller than the first flow path cross-sectional area S1 of the opening end 28 of the other flow path 27 and larger than the second flow path cross-sectional area S2.

Other than this, the configuration is similar to that of the outdoor heat exchanger 11 shown in Figures 3 to 5, so the same components are given the same symbols and their descriptions will not be repeated unless necessary.

Next, an example of a method for manufacturing the above-mentioned outdoor heat exchanger 11 will be described. After going through steps similar to those shown in steps T1, T2, and T3 in FIG. 6, the molded body is cut and shrunk (step T4).

As shown in Figure 19, here, the molded body 20 is cut along a direction inclined with respect to the Y-axis direction. The cut surfaces of the cut molded body 20 form opening end faces 26, with each of the multiple flow paths 27 (see Figure 18) opening. At this time, as the molded body 20 is cut, a tapered first side portion 29a and a tapered second side portion 29b are formed in both the first side portion 29a and the second side portion 29b of the molded body 20 in such a manner that the width of the molded body 20 decreases as it approaches the opening end face 26.

The tapered first side portion 29a is formed by applying pressure (pressure A: see arrow P1). The tapered second side portion 29b is formed by applying a pressure (pressure B: see arrow P2) lower than pressure A.

By making the relationship of the pressures for forming the tapered shape such that pressure A is greater than pressure B, the length narrowed in the Y-axis direction at the second opening end 28b of the second flow path 27b closest to the second side portion 29b at the opening end face 26 is shorter than the length narrowed at the first opening end 28a of the first flow path 27a closest to the first side portion 29a.

18, the second open end 28b of the second flow passage 27b is formed to have a third flow passage cross-sectional area S3 larger than the second flow passage cross-sectional area S2 of the first open end 28a of the first flow passage 27a. In this way, the flat heat transfer tube 21 including the main body 23 and the connection portion 25 is completed (step T5).

Next, in step T6, the flat heat transfer tube 21 is connected to the header 31. At this time, since both the first side portion 29a and the second side portion 29b are tapered, it is easy to insert the flat heat transfer tube 21 into the opening 33 of the header 31. In addition, the length to which the connection portion 25 is inserted into the header 31 is uniquely defined, and it is possible to prevent the connection portion 25 from being inserted, for example, into the opening 33 of the header 31 more than necessary. In this way, the installation of the flat heat transfer tube 21 to the header 31 is completed, and the main part of the outdoor heat exchanger 11 is completed.

According to the above-mentioned outdoor heat exchanger 11, it is possible to obtain both the effects of the outdoor heat exchanger 11 described in embodiment 2 and the effects of the outdoor heat exchanger 11 described in embodiment 3.

First, in the connection portion 25 of the flat heat transfer tube 21 of the outdoor heat exchanger 11 described above, the opening end face 26 is positioned along a direction inclined with respect to the Y-axis direction in a manner approaching the main body portion 23 from the first side portion 29a toward the second side portion 29b.

As a result, the length of the first flow path 27a becomes longer than the length of the second flow path 27b, and the flow path resistance (friction resistance) of the first flow path 27a becomes higher than the flow path resistance (friction resistance) of the second flow path 27b, making it easier for the refrigerant to flow into the second flow path 27b located on the upwind side.

In addition, both the first side portion 29a and the second side portion 29b are tapered in the connection portion 25. In the open end surface 26 in the connection portion 25, the second open end 28b of the second flow path 27b closest to the second side portion 29b has a third flow path cross-sectional area S3 that is smaller than the first flow path cross-sectional area S1 of the open end 28 of the other flow path 27 and larger than the second flow path cross-sectional area S2.

As a result, for the second flow passage 27b located on the windward side where a larger amount of refrigerant is required to flow, the tapered second side portion 29b on the windward side can be formed to minimize the difficulty in the refrigerant flowing through the second flow passage 27b. As a result, the heat transfer performance of the outdoor heat exchanger 11 can be maintained.

Furthermore, in the connection portion 25, both the first side portion 29a and the second side portion 29b are tapered, which makes it easier to insert the connection portion 25 into the opening 33 formed in the header 31. As a result, this contributes to improving the manufacturability of the outdoor heat exchanger 11.

In addition, the tapered first side portion 29a and the tapered second side portion 29b of the connection portion 25 contact the inner wall surface 34 of the opening 33, which can prevent the connection portion 25 from being inserted, for example, more than necessary into the opening 33 of the header 31. As a result, it is possible to contribute to stabilizing the flow of the refrigerant in the header 31.

In the above-described embodiments, a single-row outdoor heat exchanger 11 has been described as an example (see FIG. 2). The outdoor heat exchanger 11 may be a multi-row type, or may be a two-row outdoor heat exchanger 11 in which the outdoor heat exchanger 11a and the outdoor heat exchanger 11b are arranged along the air flow direction as shown in FIG. 20.

In such an outdoor heat exchanger 11, the outdoor heat exchangers 11 according to embodiments 1 to 4 can be applied to the portion shown in the dotted frame DL where the flat heat transfer tubes of the outdoor heat exchanger 11a are connected to the header 31a and to the portion where the flat heat transfer tubes of the outdoor heat exchanger 11b are connected to the header 31b.

Furthermore, the outdoor heat exchanger may have three or more rows of outdoor heat exchangers. It may also be applied not only to the outdoor heat exchanger 11 but also to the indoor heat exchanger 5 as necessary.

The outdoor heat exchangers described in each embodiment can be combined in various ways as needed.

The embodiments disclosed herein are illustrative and are not intended to be limiting. The present disclosure is defined by the scope of the claims, not the scope described above, and is intended to include all modifications within the meaning and scope of the claims.

The present disclosure is effectively used in heat exchangers equipped with flat heat transfer tubes.

1 refrigeration cycle device, 3 compressor, 5 indoor heat exchanger, 7 fan, 9 expansion valve, 10 housing, 11 outdoor heat exchanger, 13 propeller fan, 15 four-way valve, 17 refrigerant piping, 20 molded body, 21 flat heat transfer tube, 23 main body, 25 connection portion, 26 opening end surface, 27 flow path, 27a first flow path, 27b second flow path, 28 opening end, 28a first opening end, 28b second opening end, 29a first side portion, 29b second side portion, 31 header, 33 opening, 34 opening inner wall surface, 41 heat dissipation fin, S1 first flow path cross-sectional area, S2 second flow path cross-sectional area, S3 third flow path cross-sectional area, Y1, P1, P2, P3 arrows (inserted), DL frame.

Claims (8)

a flat heat transfer tube having a first side portion and a second side portion separated by a width in a first direction and extending in a second direction intersecting the first direction, the flat heat transfer tube having a plurality of flow paths each extending in the second direction and arranged at intervals in the first direction;
a header having an opening and the flat heat transfer tube connected to the opening;
and a heat dissipation fin.
The flat heat transfer tube is
A main body portion attached to the heat dissipation fin;
a connection portion having an open end surface at which each of the plurality of flow paths is open, the connection portion being inserted into the opening of the header and connected to the header,
In the main body portion, each of the plurality of flow paths has a first flow path cross-sectional area,
In the connection portion, only the first side portion is formed in a tapered shape such that the width is reduced as the first side portion approaches the opening end surface,
a first opening end of a first flow passage, among the plurality of flow passages, that is closest to the first side portion that is tapered, has a second flow passage cross-sectional area that is smaller than the first flow passage cross-sectional area, at the opening end surface. a flat heat transfer tube having a first side portion and a second side portion separated by a width in a first direction and extending in a second direction intersecting the first direction, the flat heat transfer tube having a plurality of flow paths each extending in the second direction and arranged at intervals in the first direction;
a header having an opening and the flat heat transfer tube connected to the opening;
Heat sink fins and
having
The flat heat transfer tube is
A main body portion attached to the heat dissipation fin;
a connection portion having an open end surface at which each of the plurality of flow paths is open, the connection portion being inserted into the opening of the header and connected to the header;
Equipped with
In the main body portion, each of the plurality of flow paths has a first flow path cross-sectional area ,
In the connection portion, the first side portion is formed in a tapered shape such that the width is reduced as the first side portion approaches the opening end surface,
At the opening end surface, a first opening end of a first flow passage, among the plurality of flow passages, that is closest to the first side portion formed in a tapered shape has a second flow passage cross-sectional area that is smaller than the first flow passage cross-sectional area,
In the connection portion, the second side portion is formed in a tapered shape such that the width is reduced as the second side portion approaches the opening end surface,
At the opening end surface, a second opening end of a second flow path, among the plurality of flow paths arranged along the first direction, that is closest to the second side portion formed in a tapered shape has a third flow path cross-sectional area that is smaller than the first flow path cross-sectional area and larger than the second flow path cross-sectional area ,
A heat exchanger, wherein, at the connection portion, the first side portion is tapered more inward in the width direction of the flattened heat transfer tube than the second side portion . The heat exchanger according to claim 1 , wherein the tapered first side portion is in contact with an inner wall surface of the opening of the header. the tapered first side portion contacts an inner wall surface of the opening of the header,
The heat exchanger according to claim 2 , wherein the tapered second side portion is in contact with an inner wall surface of the opening of the header. The heat exchanger according to any one of claims 1 to 4, wherein the open end surface is located along the first direction. The heat exchanger according to any one of claims 1 to 4, wherein the open end surface is positioned along a third direction intersecting the first direction, in a manner that approaches the main body from the first side portion toward the second side portion. The heat exchanger according to any one of claims 1 to 6, wherein the flat heat transfer tube is arranged so that the first side is located on the downwind side and the second side is located on the upwind side. A refrigeration cycle device equipped with a heat exchanger according to any one of claims 1 to 7.

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