JP2021055986A - Heat exchanger and air conditioner including the same - Google Patents

Abstract

To provide a heat exchanger capable of improving rigidity to insertion stress in inserting heat transfer tubes to insertion portions of a fin, and rigidity to thermal stress of the fin in brazing.SOLUTION: A heat exchanger includes a plurality of flat heat transfer tubes, and a fin 1, and the heat transfer tubes are arranged in a manner that flat portions are opposed to each other. The fin 1 has: an air flow upstream end and an air flow downstream end in an air flowing direction; insertion portions 7 formed from an air flow downstream end side to insert the heat transfer tubes; flat portions 1c respectively formed between the adjacent insertion portions 7; first ribs 3 formed in a manner of projecting from the flat portions 1c along a longitudinal direction of the insertion portions 7; second ribs 4 formed at an upper part of the insertion portions 7 in a manner of projecting from the flat portions 1c at the air flow downstream end side along a direction orthogonal to the longitudinal direction of the insertion portions 7; and L-shaped condensate water flow channels L1 respectively formed by making a rising end line at an insertion portion side of the first rib 3 and a rising end line at the air flow downstream end side of the second rib 4 intersect each other on their extension lines.SELECTED DRAWING: Figure 3B

Description

The present invention relates to a heat exchanger and an air conditioner including the heat exchanger.

In the manufacturing process of the heat exchanger of the air conditioner, when the heat transfer tube and the fins are brazed, they are softened by heat and further thermally expanded. Therefore, if the rigidity of the fin against thermal stress is low, a gap is generated in the brazed portion with the heat transfer tube due to the deformation of the fin, and the brazing rate (brazing strength, brazing area) decreases. This leads to a decrease in heat exchanger performance.

The heat exchanger of Patent Document 1 includes a plurality of flat heat transfer tubes through which a refrigerant for heat exchange with air flows, and fins having a heat exchange surface between the plurality of heat transfer tubes. The plurality of heat transfer tubes are arranged side by side so that the flat portions of the heat transfer tubes face each other, and the fins have one end and the other end in the airflow direction and a first rib formed vertically above the flat portion. The first rib is formed by a stretched portion (3a) extending along the flat portion and an enlarged portion (3b) in which the distance from the stretched portion to the flat portion gradually increases in the direction toward one end. It has a reduced portion (3c) in which the distance from the enlarged portion to the flat portion gradually decreases in the direction toward one end. With this configuration, the water accumulated in the upper part of the flat pipe can be quickly discharged, and the ventilation resistance can be reduced.

Further, in Patent Document 1, as a third embodiment, the second rib 4 is extended above the first rib 3 from the rear of the fin 12 in the airflow direction toward the enlarged portion 3b of the first rib 3. It is disclosed that the water droplet 214 falling from above can be moved above the enlarged portion 3b of the first rib 3 and can be drained more efficiently.

Japanese Patent No. 6466631

According to Patent Document 1, in consideration of drainage, ribs are provided around the insertion portion of the heat transfer tube or at an unevenly distributed position in the leeward direction. Therefore, in the flat surface portion of the fin, the region without ribs tends to be large. Therefore, there is a problem that the rigidity against various stresses is low in the region without ribs.
For example, when a flat heat transfer tube is inserted into the fin insertion portion and attached, if the fin is thin and the area of the fin flat surface is large, the rigidity is low, so that the fin is easily deformed or broken. There are challenges.
Further, when the heat transfer portion which is the fin flat portion has a cantilever structure supported on the wind side, if only the first rib 3 which is a serpentine bead as in Patent Document 1 is provided, the heat exchanger and the heat exchanger The fin plane cannot withstand the thermal stress generated by the thermal expansion of the fin itself and the flat heat transfer tube during brazing (for example, the stress that the fin flat surface sandwiched between adjacent flat heat transfer tubes bows and deforms). The part is deformed. As the amount of deformation increases toward the leeward side, there is a problem that the bonding rate between the fin and the flat heat transfer tube (bonding rate at the time of attachment and bonding durability) also decreases.

The present invention provides a heat exchanger having a fin structure capable of improving the rigidity against the insertion stress when inserting the heat transfer tube into the insertion portion of the fin and the rigidity against the thermal stress of the fin when brazing. To do.
It also provides an air conditioner equipped with the heat exchanger.

The heat exchanger of the present invention
Multiple flat heat transfer tubes through which the refrigerant for heat exchange with air flows inside,
A fin having a heat exchange surface between the plurality of heat transfer tubes is provided.
The plurality of heat transfer tubes are arranged side by side so that the flat portions of the heat transfer tubes face each other.
The fins
The upstream end of the airflow (upper end of the wind) and the downstream end of the airflow (lower end of the wind) in the direction of the airflow,
An insertion portion formed from the downstream end side of the air flow and in which the heat transfer tube is arranged,
A flat surface portion formed between the adjacent insertion portions and
A first rib (snake-shaped bead) formed above the insertion portion along the longitudinal direction of the insertion portion so as to project from the flat surface portion.
A second rib (vertical bead) formed above the insertion portion along a direction orthogonal to the longitudinal direction of the insertion portion so as to project from the plane portion on the downstream end side of the air flow.
The rising end line on the insertion portion side of the first rib and the rising end line on the downstream end side of the air flow of the second rib intersect on their extension lines (including intersections orthogonal or substantially orthogonal to each other). Or the flow path of L-shaped condensed water (condensed water) formed by connecting,
Have.

According to the present invention, it is possible to improve the rigidity against the insertion stress when the heat transfer tube is inserted into the insertion portion of the fin.
In addition, the rigidity of the fins against thermal stress during brazing can be improved.
Further, the second bead (vertical bead) improves the rigidity of the heat transfer portion on the leeward side against thermal stress, and as a result, the bonding ratio is improved. Further, the second bead serves as a guide for flowing the condensed water (condensed water) generated on the leeward side in the direction of gravity, and as a result, the drainage property is improved.

It is the schematic of the air conditioner provided with the heat exchanger which concerns on Embodiment 1. FIG. It is a perspective view which shows the appearance of the heat exchanger of the air conditioner which concerns on Embodiment 1. FIG. It is a figure for demonstrating the shape of the fin which concerns on Embodiment 1. FIG. It is a top view of the shape of the fin which concerns on Embodiment 1. FIG. It is a figure for demonstrating the multi-stage arrangement state of fins which concerns on Embodiment 1. FIG. It is a top view of the shape of the fin which concerns on Embodiment 2. FIG. It is a top view of the shape of the fin which concerns on embodiment 3. It is a top view of the shape of the fin which concerns on Embodiment 4. FIG. It is a top view of the shape of the fin which concerns on embodiment 5. It is a top view of the shape of the fin which concerns on Embodiment 6. It is a top view of the shape of the fin which concerns on Embodiment 7. It is a top view of the shape of the fin which concerns on embodiment 8. FIG. 5 is a plan view of the shape of the fin according to the ninth embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same reference numerals are given to common parts in each figure, and duplicate description is omitted.
(First Embodiment)
FIG. 1 is a block diagram of a refrigeration cycle of an air conditioner according to the first embodiment of the present invention.
As shown in FIG. 1, the air conditioner 100 is composed of an outdoor unit 101 installed outdoors (non-air-conditioned space) on the heat source side and an indoor unit 108 installed indoors (air-conditioned space) on the user side. , Connected by connecting pipes 112a, 112b.

(Air conditioner 100)
The outdoor unit 101 includes a compressor 102, a four-way valve 103, an outdoor heat exchanger 104, an outdoor fan motor 105, an outdoor fan 106, and a throttle device 107, and the indoor unit 108 includes an indoor heat exchanger 109. , The indoor fan motor 110 and the indoor fan 111 are provided.

The operation of each element of the air conditioner 100 will be described by taking the operation during the cooling operation as an example.
During the cooling operation, the refrigerant flows in the direction of the solid arrow in FIG. First, the high-temperature, high-pressure gas refrigerant discharged from the compressor 102 flows to the outdoor heat exchanger 104 after passing through the four-way valve 103, and is condensed by dissipating heat to the outside air in the outdoor heat exchanger 104, resulting in high pressure. It becomes a liquid refrigerant. This liquid refrigerant is depressurized by the action of the throttle device 107, becomes a low-temperature low-pressure gas-liquid two-phase state, and flows to the indoor unit 108 through the connection pipe 112a. The gas-liquid two-phase refrigerant contained in the indoor unit 108 evaporates by absorbing the heat of the indoor air in the indoor heat exchanger 109, whereby indoor cooling is realized. The gas refrigerant evaporated in the indoor unit 108 returns to the outdoor unit 101 through the connecting pipe 112b, and is compressed again by the compressor 102 through the four-way valve 103. This is the refrigeration cycle during cooling operation.

During the heating operation, the four-way valve 103 switches the refrigerant flow path, and the refrigerant flows in the direction of the broken line arrow in FIG. First, the high-temperature, high-pressure gas refrigerant discharged from the compressor 102 flows to the indoor unit 108 through the four-way valve 103 and the connecting pipe 112b. The high-temperature gas refrigerant that has entered the indoor unit 108 is dissipated to the indoor air by the indoor heat exchanger 109 to realize indoor heating. At this time, the gas refrigerant condenses and becomes a high-pressure liquid refrigerant. After that, the high-pressure liquid refrigerant flows to the outdoor unit 101 through the connection pipe 112a. The high-pressure liquid refrigerant that has entered the outdoor unit 101 is depressurized by the action of the throttle device 107, becomes a low-temperature low-pressure gas-liquid two-phase state, flows to the outdoor heat exchanger 104, and evaporates by absorbing the heat of the outdoor air. , Becomes a gas refrigerant. This gas refrigerant passes through the four-way valve 103 and is then compressed again by the compressor 102. This is the refrigeration cycle during heating operation.
As described above, the directions of the refrigerant flows in the outdoor heat exchanger 104 and the indoor heat exchanger 109 are opposite in the cooling operation and the heating operation. Although R32 is used as the refrigerant, another refrigerant such as R410A may be used.

(Heat exchanger 10)
FIG. 2 is a perspective view showing the appearance of the heat exchanger 10 of the air conditioner 100, and is an example when a parallel flow type heat exchanger is used as an evaporator.
The heat exchanger 10 corresponds to the outdoor heat exchanger 104 and the indoor heat exchanger 109 of the air conditioner 100 shown in FIG.
As shown in FIG. 2, the heat exchanger 10 has two headers 50 composed of an inflow side header on the left side in the figure for distributing the refrigerant and an outflow side header on the right side in the figure for merging the refrigerant, and between these headers 50. A plurality of flat tubes 2 (heat transfer tubes) through which a refrigerant for heat exchange with air flows, and a plurality of fins 1 brazed to the flat tubes 2 to expand the heat transfer area. Be prepared.

As shown in FIG. 2, the flow direction of the refrigerant (see the broken line arrow) and the flow direction of the air (see the white arrow) are orthogonal to each other, and the refrigerant flowing in the flat pipe 2 and the air flowing between the flat pipes 2 However, efficient heat exchange is realized by heat exchange via the fin 1.

FIG. A3 is a perspective view showing a main part of the fin 1 brazed to the flat tube 2 of the heat exchanger 10.
The plurality of flat tubes 2 are arranged side by side so that the flat portions 2c of the flat tubes 2 face each other.
As shown in FIGS. 3A and 3B, the fin 1 has a flat plate shape and has an insertion portion 7 into which the flat tube 2 is inserted, and a plurality of flat tubes 2 are arranged side by side in the extending direction of the flat tube 2. The flat tube 2 is configured by being inserted into the insertion portion 7.

As shown in FIGS. 3A to 3B, the fin 1 includes one end (front edge of the fin) 1a and the other end 1b, which are edges in the airflow direction, and a flat surface portion 1c of the fin 1 sandwiched between the flat tubes 2. It has a first rib 3, a second rib 4, and a third rib 5 formed vertically above the flat portion 2c of the flat tube 2. Further, a long rib 9 is formed on one end portion 1a side of the fin 1 along the longitudinal direction of the fin 1. The first rib 3 is sometimes referred to as a serpentine bead. The second rib 4 is sometimes referred to as a vertical girder bead. One end 1a corresponds to the upstream end of the airflow, and the other end 1b corresponds to the downstream end of the airflow.

The first rib 3 includes a stretched portion 3a that extends along the flat portion 2c of the flat tube 2, and an enlarged portion 3b in which the distance between the stretched portion 3a and the flat portion 2c gradually increases in the direction toward one end portion 1a. It has a reduced portion 3c in which the distance from the enlarged portion 3b to the flat portion 2c gradually decreases in the direction toward one end portion 1a. The stretched portion 3a is configured to be stretched to the upper side near the trailing edge 2b of the flat tube. The reduced portion 3c is gradually reduced at a predetermined angle formed with the flat portion 2c of the flat tube 2 and extends upward near the front edge 2a of the flat tube.

The second rib 4 is formed vertically above the flat portion 2c and the first rib 3 and on the other end 1b side along a direction orthogonal to the longitudinal direction of the insertion portion 7. Since the insertion portion 7 is formed so as to cut out the other end portion 1c and cantilevers the transmission tube 2, it is expected that the thermal deformation of the flat surface portion 1c on the other end portion 1b side will be large. The second rib 4 can reduce thermal deformation.

The third rib 5 is formed so as to extend linearly along the flat portion 2c vertically above the flat portion 2c and the first rib 3.

In the present embodiment, the protruding cross sections of the first, second, and third ribs 3, 4, and 5 are arcuate, and the protruding heights are the same. The length in the protruding longitudinal direction is different, but the length in the protruding width direction is the same.

As shown in FIG. 3B, in the flow path L1, the rising end line 301 on the insertion portion 7 side of the first rib 3 and the rising end line 401 on the downstream end side of the air flow of the second rib 4 are on their extension lines. It is formed by intersecting (including orthogonal or substantially orthogonal intersections). The flow path L1 has an L-shaped appearance and functions as a flow path for condensed water (condensed water) that falls due to gravity.
In FIG. 3B, the rising end line 401 on the downstream end side of the airflow of the second rib 4 contacts the tip of the downstream end of the airflow of the first rib 3 in the extending direction thereof. It is also a place where the direction of the flow path L1 is changed, and the flow path L1 is formed so as not to block the flow of the condensed water. That is, it is preferable that the rising end line 401 on the downstream end side of the airflow of the second rib 4 does not collide with the first rib 3 in the extending direction thereof.
Therefore, in the present embodiment, the second rib 4 improves the rigidity of the heat transfer portion on the leeward side against thermal stress, and as a result, the joining ratio is improved. Further, the second rib 4 serves as a guide for flowing the condensed water (condensed water) generated on the leeward side in the direction of gravity, and as a result, the drainage property is improved.

FIG. 3C shows a multi-stage arrangement of fins.
In the flat surface portion 1c of the fin 1, a stepped portion 7a is formed at the peripheral portion of the insertion portion 7. The fin collar 7b is erected from the step portion 7a. By squeezing the peripheral portion (the root portion of the fin collar) of the insertion portion 7 one step, the rigidity against thermal stress can be further improved. Further, not only the rigidity against thermal stress can be improved, but also the rigidity against stress applied when the heat transfer tube is inserted can be improved.
The fin collar 7b is formed with a bent portion 7c that bends and extends vertically from the tip thereof in a direction away from the insertion portion 7. In the present embodiment, four bent portions 7c are formed, but the present invention is not limited to this. When the fins 1 are arranged in multiple stages, the flat portion of the refracted portion 7c is formed in the recessed portion (back surface) of the stepped portion 7a. Contact. As a result, the distance between adjacent fins 1 can be made constant.

(Embodiment 2)
In the first embodiment, the third rib 5 is formed on the flat surface portion 1c, but the third rib 5 may not be formed.
In the second embodiment shown in FIG. 4, only the first and second ribs 3 and 4 are formed. The second rib 4 exerts the same effect as that of the first embodiment.

(Embodiment 3)
A plan view of the fins of the third embodiment is shown in FIG. 5A.
The third rib 51 is formed so as to extend linearly above the extending portion 3a of the first rib 3 and parallel to the vertical direction of the second rib 4.
The fourth rib 52 is formed so as to extend linearly above the enlarged portion 3b of the first rib 3 and parallel to the vertical direction of the second rib 4.
The protrusion sizes of the second rib 4, the third rib 51, and the fourth rib 52 may be the same or different.
The second rib 4, the third rib 51, and the fourth rib 52 are arranged in three rows, but the row spacing may be the same or different.

(Embodiment 4)
A plan view of the fins of the fourth embodiment is shown in FIG. 5B. In FIG. 5A of the third embodiment, the third rib 51 and the fourth rib 52 are formed, but only one of them may be used.
In the fourth embodiment shown in FIG. 5B, the third rib 51 is omitted, and the fourth rib 52 is linear above the boundary between the extending portion 3a and the expanding portion 3b and parallel to the vertical direction of the second rib 4. It is formed so as to extend to.

(Embodiment 5)
A plan view of the fins of the fifth embodiment is shown in FIG. 5C. In FIG. 5A of the third embodiment, the third rib 51 and the fourth rib 52 are formed, but only one of them may be used.
In the fifth embodiment shown in FIG. 5C, the third rib 51 is omitted, and the fourth rib 52 is formed in a rectangular shape upward over a part of the extending portion 3a and the enlarged portion 3b.

(Embodiment 6)
A plan view of the fins of the sixth embodiment is shown in FIG. 5D. The configuration is different from that of the flow path L1 formed by the first rib and the second rib of the first to fifth embodiments.
In FIG. 5D of the sixth embodiment, the rising end line 301 of the first rib 3 on the insertion portion 7 side comes into contact with the tip of the second rib 4 on the insertion portion 7 side in the extending direction thereof. It is also a place where the direction of the flow path L1 is changed, and the flow path L1 is formed so as not to block the flow of the condensed water. That is, it is preferable that the rising end line 301 on the insertion portion 7 side of the first rib 3 does not collide with the second rib 4 in the extending direction thereof.

(Embodiment 7)
A plan view of the fins of the seventh embodiment is shown in FIG. 5E. In the seventh embodiment, the third rib 37 is formed in addition to the first and second ribs 3 and 4 of the sixth embodiment. The third rib 37 has a shape in which the first rib 3 is turned upside down.

(Embodiment 8)
A plan view of the fins of the eighth embodiment is shown in FIG. 5F. In the eighth embodiment, the downstream end of the airflow of the first rib 3 and the lower end of the second rib 4 are connected by the connecting portion 41, and the downstream end of the airflow of the third rib 37 having the shape of the first rib 3 turned upside down and the second rib. The upper ends of the two ribs 4 are connected by a connecting portion 42. Further, the fourth rib 38 is formed so as to connect the extended portion 3a of the first rib 3 and the extended portion 37a of the third rib 37.

(Embodiment 9)
A plan view of the fins of the ninth embodiment is shown in FIG. 5G. In the eighth embodiment
The first and second ribs 3 and 4 are the same as those in the first embodiment (FIG. 3B).
The third rib 41 is formed vertically above the flat portion 2c and the first rib 3 in a straight line along a direction intersecting the longitudinal direction of the insertion portion 7 (intersecting at an inclination of 30 to 60 degrees).
The fourth rib 51 is formed vertically above the flat portion 2c and the first rib 3 so as to extend linearly along the flat portion 2c with the third rib 41 in between. The fourth rib 51 is linear.

(Separate embodiment)
In the first to ninth embodiments, the step portion 7a may or may not be formed in the peripheral portion of the insertion portion 7. The fin collar may be erected without a step.
In the first to ninth embodiments, the first rib 3 has a shape having a stretched portion 3a, an enlarged portion 3b, and a reduced portion 3c, but is not limited to this, and is a linear shape extending along a flat portion. It may be a shape having a stretched portion and a reduced portion in which the distance from the stretched portion to the flat portion 2c gradually decreases in the direction toward one end portion 1a.
Further, as another embodiment, the rib has an external shape (straight line, arc shape, irregular shape, etc.), a protruding cross-sectional shape (arc shape, rectangular shape, triangular shape, etc.), a length in the protruding longitudinal direction, and a length in the protruding width direction. The protrusion height and the like may all be the same or different.

(Thermal deformation analysis)
The results of thermal deformation analysis simulation of Embodiments 1 to 9 and Patent Document 1 (Comparative Example) are shown.
1. 1. Analysis conditions Temperature: 600 ° C
Fin material: In order to imitate the state where the aluminum heat transfer tube is inserted, the edge of the fin collar that touches when the heat transfer tube is inserted is fixed and analyzed.
2. Analysis result In the comparative example, thermal deformation was confirmed in the flat surface portion 1c where the ribs were not formed.
In the first to ninth embodiments, less thermal deformation than in Comparative Example 1 was confirmed in the flat surface portion 1c in which the ribs were not formed. Since the thermal deformation is small, stress deformation is less likely to occur when heat is applied during brazing than in Comparative Example 1, and the brazing rate of the fins and the heat transfer tube (brazing strength, brazing area). Is improved.

(Effect of embodiment)
If the ribs are unevenly distributed in the direction of gravity and the leeward direction in the flat surface portion sandwiched between the heat transfer tubes of the fins as in Patent Document 1 of the prior art, the area of the region without the ribs tends to increase. In the ribless region, the thermal stress of the fins is low. On the other hand, if the ribs are provided on the flat surface portion, the ribs are evenly arranged and the area without the ribs is considered to be small. However, when the rib is provided as a target, the alignment of the region without the rib tends to be long, and when heat is applied to the fin, the alignment tends to be deformed along the alignment.

1 Fin 1a One end (front edge of fin)
1b End end 1c Flat part 2 Flat tube (heat transfer tube)
2c Flat part 3 1st rib 3a Extension part 3b Expansion part 3c Reduction part 4 Second rib 7 Insertion part 10 Heat exchanger 50 Header 100 Air conditioner 101 Outdoor unit 102 Compressor 103 Four-way valve 104 Outdoor heat exchanger 105 Outdoor fan Motor 106 Outdoor fan 107 Squeezing device 108 Indoor unit 109 Indoor heat exchanger 110 Indoor fan Motor 111 Indoor fan 112a, 112b Connection piping

Claims (5)

Multiple flat heat transfer tubes through which the refrigerant for heat exchange with air flows inside,
A fin having a heat exchange surface between the plurality of heat transfer tubes is provided.
The plurality of heat transfer tubes are arranged side by side so that the flat portions of the heat transfer tubes face each other.
The fins
The upstream and downstream ends of the airflow in the direction of the airflow,
An insertion portion formed from the downstream end side of the air flow and in which the heat transfer tube is arranged,
A flat surface portion formed between the adjacent insertion portions and
A first rib formed above the insertion portion along the longitudinal direction of the insertion portion so as to project from the flat surface portion.
A second rib formed above the insertion portion along a direction orthogonal to the longitudinal direction of the insertion portion so as to project from the plane portion on the downstream end side of the air flow.
An L-shape formed by intersecting or connecting the rising end line of the first rib on the insertion portion side and the rising end line of the second rib on the downstream end side of the air flow on their extension lines. A heat exchanger having a flow path of condensed water in the shape of a heat exchanger. The first rib includes a stretched portion extending along the flat portion, an enlarged portion in which the distance from the stretched portion to the flat portion gradually increases in the direction of one end side, and one end side from the enlarged portion. The heat exchanger according to claim 1, further comprising a reduced portion in which the distance from the flat portion gradually decreases in the direction of the above. The heat exchanger according to claim 1 or 2, further comprising a third rib on the flat surface portion. The heat exchanger according to any one of claims 1 to 3, wherein a step portion is provided around the insertion portion and a fin collar is erected from the step portion. An air conditioner comprising the heat exchanger according to any one of claims 1 to 4.

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