JP7209670B2 - Heat exchanger and air conditioner provided with the same - Google Patents

Description

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

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

The heat exchanger of Patent Document 1 includes a plurality of flat heat transfer tubes in which a refrigerant for exchanging heat 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 portions. The first rib includes an extended portion (3a) extending along the flat portion and an enlarged portion (3b) in which the distance from the flat portion gradually increases from the extended portion toward the one end side. and a reduced portion (3c) in which the distance from the flat portion gradually decreases in the direction from the enlarged portion toward the one end side. With this configuration, the water accumulated in the upper portion of the flat tube can be quickly discharged, and the airflow resistance can be reduced.

Further, in Patent Document 1, as a third embodiment, the second rib 4 is arranged above the first rib 3 so as to extend 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 droplets 214 falling from above can be moved to above the enlarged portions 3b of the first ribs 3, thereby enabling more efficient drainage.

Japanese Patent No. 6466631

According to Patent Literature 1, ribs are provided around the insertion portion of the heat transfer tube or at unevenly distributed positions in the downwind direction in consideration of drainage. For this reason, in the planar portion of the fin, the region without ribs tends to be large. For this reason, there is a problem that the rigidity against various stresses is low in the regions without ribs.
For example, when a flat heat transfer tube is inserted into the fin insertion part and attached, if the fin thickness is thin and the fin flat surface area is large, the rigidity will be low, so the fin will deform or break easily. I have a problem.
Further, when the heat transfer portion, which is the fin plane portion, has a cantilever structure supported on the windward side, if only the first rib 3 which is a snake-shaped bead as in Patent Document 1 is provided, the heat exchanger and the The fin plane cannot withstand the thermal stress generated by the thermal expansion of the fin itself and the flat heat transfer tubes during brazing (for example, the stress that deforms the flat surface of the fin sandwiched between adjacent flat heat transfer tubes into a bow). part is deformed. Since the amount of deformation increases toward the leeward side, there is a problem that the bonding rate between the fins and the flat heat transfer tubes (bonding rate and bonding durability at the time of attachment) also decreases.

The present invention provides a heat exchanger having a fin structure that can improve the rigidity against insertion stress when heat transfer tubes are inserted into the insertion portions of the fins and the rigidity against thermal stress of the fins during brazing. do.
Also, an air conditioner provided with the heat exchanger is provided.

The heat exchanger of the present invention is
a plurality of flat heat transfer tubes in which a refrigerant for exchanging heat with air flows;
a fin 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,
The fins are
an airflow upstream end (windward end) and an airflow downstream end (leeward end) in the airflow direction;
an insertion portion formed from the downstream end of the airflow and in which the heat transfer tube is arranged;
a flat portion formed between the adjacent insertion portions;
a first rib (serpentine bead) formed above the insertion portion and protruding from the flat portion along the longitudinal direction of the insertion portion;
a second rib (vertical bead) formed above the insertion portion so as to protrude from the flat portion on the downstream end side of the airflow along a direction perpendicular to the longitudinal direction of the insertion portion;
A rising edge line of the first rib on the insertion portion side and a rising edge line of the second rib on the downstream end side of the airflow intersect on their extension line (including orthogonal or substantially orthogonal intersection). Or an L-shaped condensed water (condensed water) flow path formed by being connected,
have

ADVANTAGE OF THE INVENTION According to this invention, the rigidity with respect to the insertion stress when inserting a heat exchanger tube into the insertion part of a fin can be improved.
In addition, the rigidity against thermal stress of the fins during brazing can be improved,
In addition, the second bead (vertical bead) improves the rigidity against thermal stress on the leeward side of the heat transfer section, and as a result, the bonding rate is improved. Furthermore, the second bead serves as a guide for flowing condensed water (condensed water) generated on the leeward side in the direction of gravity, resulting in improved drainage.

1 is a schematic diagram of an air conditioner provided with a heat exchanger according to Embodiment 1. FIG. 2 is a perspective view showing the appearance of the heat exchanger of the air conditioner according to Embodiment 1. FIG. 4A and 4B are diagrams for explaining the shape of a fin according to the first embodiment; FIG. 4 is a plan view of the shape of the fins according to Embodiment 1. FIG. FIG. 4 is a diagram for explaining a multistage arrangement state of fins according to the first embodiment; 8 is a plan view of the shape of the fins according to Embodiment 2. FIG. FIG. 11 is a plan view of the shape of a fin according to Embodiment 3; FIG. 11 is a plan view of the shape of a fin according to Embodiment 4; FIG. 11 is a plan view of the shape of a fin according to Embodiment 5; FIG. 11 is a plan view of the shape of a fin according to Embodiment 6; FIG. 11 is a plan view of the shape of a fin according to Embodiment 7; FIG. 11 is a plan view of the shape of a fin according to Embodiment 8; FIG. 20 is a plan view of the shape of a fin according to Embodiment 9;

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In addition, the same code|symbol is attached|subjected to the part which is common in each figure, and the overlapping description is abbreviate|omitted.
(First embodiment)
FIG. 1 is a configuration diagram of a refrigeration cycle of an air conditioner according to a first embodiment of the present invention.
As shown in FIG. 1, an 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. , are connected by connection pipes 112a and 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 an expansion device 107. The indoor unit 108 includes an indoor heat exchanger 109 and , an indoor fan motor 110 and an indoor fan 111 .

The operation of each element of the air conditioner 100 will be described using the operation during the cooling operation as an example.
During cooling operation, the refrigerant flows in the direction of the solid line arrow in FIG. First, the high-temperature and high-pressure gas refrigerant discharged from the compressor 102 flows through the four-way valve 103 and then flows to the outdoor heat exchanger 104, where it is condensed by releasing heat to the outside air, and is converted into a high-pressure gas refrigerant. It becomes a liquid refrigerant. This liquid refrigerant is depressurized by the action of the expansion device 107, becomes a low-temperature, low-pressure gas-liquid two-phase state, and flows to the indoor unit 108 through the connecting pipe 112a. The gas-liquid two-phase refrigerant that has entered the indoor unit 108 evaporates by absorbing the heat of the indoor air in the indoor heat exchanger 109, thereby realizing indoor cooling. The gas refrigerant evaporated in the indoor unit 108 returns to the outdoor unit 101 through the connecting pipe 112b, passes through the four-way valve 103, and is compressed again by the compressor 102. This is the refrigeration cycle during cooling operation.

During heating operation, the four-way valve 103 switches the refrigerant flow path, and the refrigerant flows in the direction of the dashed arrow in FIG. First, the high-temperature, high-pressure gas refrigerant discharged from the compressor 102 flows into 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 radiates heat to the indoor air in the indoor heat exchanger 109, thereby realizing indoor heating. At this time, the gas refrigerant is condensed into a high-pressure liquid refrigerant. After that, the high-pressure liquid refrigerant flows to the outdoor unit 101 through the connecting pipe 112a. The high-pressure liquid refrigerant that has entered the outdoor unit 101 is decompressed 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 is compressed again by the compressor 102 after passing through the four-way valve 103 . This is the refrigeration cycle during heating operation.
In this manner, the directions of refrigerant flow in the outdoor heat exchanger 104 and the indoor heat exchanger 109 are opposite between cooling operation and 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 in which a parallel flow 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 includes two headers 50 consisting of an inflow side header on the left side in the drawing for distributing the refrigerant and an outflow side header on the right side in the drawing for joining the refrigerant. and a plurality of flat tubes 2 (heat transfer tubes) through which a refrigerant for exchanging heat with air flows, and a plurality of fins 1 that are brazed to the flat tubes 2 and expand the heat transfer area. Prepare.

As shown in FIG. 2, the flow direction of the refrigerant (see the dashed arrow) and the flow direction of the air (see the white arrow) are perpendicular to each other. However, by exchanging heat through the fins 1, efficient heat exchange is realized.

FIG. A3 is a perspective view showing the main part of the fins 1 brazed to the flat tubes 2 of the heat exchanger 10. FIG.
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 is flat and has an insertion portion 7 into which the flat tube 2 is inserted. The flat tube 2 is constructed by being inserted into the insertion portion 7 .

As shown in FIGS. 3A and 3B, the fin 1 has one end (fin front edge) 1a and the other end 1b, which are edges in the airflow direction, and a flat portion 1c of the fin 1 sandwiched between the flat tubes 2. , a first rib 3 , a second rib 4 , and a third rib 5 formed vertically above the flat portion 2 c of the flat tube 2 . A long rib 9 is formed along the longitudinal direction of the fin 1 on the one end portion 1 a side of the fin 1 . The first rib 3 is sometimes called a serpentine bead. The second rib 4 is sometimes called a stringer 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 an extended portion 3a that extends along the flat portion 2c of the flat tube 2, an enlarged portion 3b that gradually increases in distance from the extended portion 3a to the flat portion 2c in the direction toward the one end portion 1a, and a reduced portion 3c in which the distance from the flat portion 2c gradually decreases in the direction from the enlarged portion 3b toward the one end portion 1a. The extending portion 3a is configured to extend upward near the rear edge 2b of the flat tube. The reduced portion 3c gradually contracts at a predetermined angle 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 side of the other end portion 1b in a straight line along a direction perpendicular to the longitudinal direction of the insertion portion 7 . Since the insertion portion 7 is formed so as to cut the other end portion 1c so as to cantilever the transfer tube 2, it is expected that the flat portion 1c on the side of the other end portion 1b will be greatly thermally deformed. The second rib 4 can reduce thermal deformation.

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

In the present embodiment, the first, second and third ribs 3, 4 and 5 have arcuate protruding sections and the same protruding height. The lengths in the longitudinal direction of the protrusions are different, but the lengths in the width direction of the protrusions are the same.

As shown in FIG. 3B, the flow path L1 has a rising end line 301 on the insertion portion 7 side of the first rib 3 and a rising end line 401 on the downstream end side of the airflow of the second rib 4 on their extension lines. It is formed by being intersected (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 drops due to gravity.
In FIG. 3B, the rising edge line 401 on the downstream end of the second rib 4 contacts the tip of the downstream end of the first rib 3 in its extending direction. It is also a portion 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 edge line 401 on the downstream end side of the second rib 4 does not hit the first rib 3 in its extending direction.
Therefore, in the present embodiment, the second rib 4 improves the rigidity against the thermal stress on the leeward side of the heat transfer section, and as a result, the bonding rate is improved. In addition, the second rib 4 serves as a guide for flowing condensed water (condensed water) generated on the leeward side in the direction of gravity, and as a result, drainage is improved.

FIG. 3C shows a multistage arrangement of fins.
A stepped portion 7 a is formed around the insertion portion 7 in the planar portion 1 c of the fin 1 . A fin collar 7b is erected from the stepped portion 7a. The rigidity against thermal stress can be further improved by narrowing the peripheral portion of the insertion portion 7 (root portion of the fin collar). Moreover, not only the rigidity against thermal stress can be improved, but also the rigidity against the stress applied when the heat transfer tubes are inserted can be improved.
The fin collar 7b is formed with a bent portion 7c that extends vertically in a direction away from the insertion portion 7 from the distal end of the fin collar 7b. Although four bent portions 7c are formed in the present embodiment, the present invention is not limited to this. abut. Thereby, the interval between adjacent fins 1 can be made constant.

(Embodiment 2)
In Embodiment 1, the third rib 5 is formed on the plane portion 1c, but a configuration in which the third rib 5 is not formed may be adopted.
In Embodiment 2 shown in FIG. 4, only the first and second ribs 3, 4 are formed. The second rib 4 exhibits the same effects as those of the first embodiment.

(Embodiment 3)
A plan view of the fin of Embodiment 3 is shown in FIG. 5A.
The third rib 51 is formed above the extending portion 3 a of the first rib 3 and extends linearly in parallel with the longitudinal direction of the second rib 4 .
The fourth rib 52 is formed above the enlarged portion 3 b of the first rib 3 and extends linearly in parallel with the longitudinal direction of the second rib 4 .
Each projection size 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, and the row intervals may be the same or different.

(Embodiment 4)
A plan view of the fin of Embodiment 4 is shown in FIG. 5B. Although the third rib 51 and the fourth rib 52 are formed in FIG. 5A of Embodiment 3, only one of them may be formed.
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 extended portion 3a and the enlarged portion 3b and parallel to the longitudinal direction of the second rib 4. It is formed so as to extend to

(Embodiment 5)
A plan view of the fin of Embodiment 5 is shown in FIG. 5C. Although the third rib 51 and the fourth rib 52 are formed in FIG. 5A of Embodiment 3, only one of them may be formed.
In Embodiment 5 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 extended portion 3a and the enlarged portion 3b.

(Embodiment 6)
A plan view of the fin of Embodiment 6 is shown in FIG. 5D. The configuration is different from that of the flow path L1 formed by the first ribs and the second ribs of Embodiments 1 to 5 above.
In FIG. 5D of Embodiment 6, the rising end line 301 of the first rib 3 on the insertion portion 7 side contacts the tip of the second rib 4 on the insertion portion 7 side in its extending direction. It is also a portion 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. In other words, it is preferable that the rising end line 301 of the first rib 3 on the side of the insertion portion 7 does not hit the second rib 4 in its extending direction.

(Embodiment 7)
A plan view of the fin of Embodiment 7 is shown in FIG. 5E. In the seventh embodiment, a 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 inverted upside down.

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

(Embodiment 9)
A plan view of the fin of Embodiment 9 is shown in FIG. 5G. In Embodiment 8,
The first and second ribs 3, 4 are the same as in Embodiment 1 (Fig. 3B).
The third rib 41 is linearly formed vertically above the flat portion 2c and the first rib 3 along a direction that intersects the longitudinal direction of the insertion portion 7 (intersects 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 and extends linearly along the flat portion 2c with the third rib 41 interposed therebetween. The fourth rib 51 is linear.

(another embodiment)
In Embodiments 1 to 9, the stepped portion 7a may or may not be formed in the peripheral portion of the insertion portion 7 . The fin collar may be erected without the stepped portion.
In Embodiments 1 to 9, the first rib 3 has a shape having the extended portion 3a, the enlarged portion 3b, and the reduced portion 3c, but is not limited thereto, and has a linear shape extending along the flat portion. or a shape having an extended portion and a contracted portion in which the distance from the flat portion 2c gradually decreases in the direction from the extended portion toward the one end portion 1a.
Further, as another embodiment, the rib has an external shape (linear, arcuate, irregular shape, etc.), a projecting cross-sectional shape (arctic, rectangular, triangular, etc.), a projecting longitudinal length, a projecting width direction length height, protrusion height, etc. 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. Analysis conditions Temperature: 600°C
Fin material: aluminum In order to simulate the state in which the heat transfer tube is inserted, the edge of the fin collar that touches when the heat transfer tube is inserted was fixed and analyzed.
2. Analysis Results In the comparative example, thermal deformation was confirmed in the flat portion 1c where the rib was not formed.
In Embodiments 1 to 9, less thermal deformation than in Comparative Example 1 was confirmed in the flat portion 1c where no rib was 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 heat transfer tubes (brazing strength, brazing area) improves.

(Effect of Embodiment)
If the ribs are unevenly distributed in the direction of gravity and the leeward direction on the flat portion of the fin sandwiched between the heat transfer tubes as in the prior art of Patent Document 1, the area of the rib-free region tends to increase. In areas without ribs, the thermal stress of the fins is low. On the other hand, if the ribs are provided symmetrically on the plane portion, the ribs are arranged evenly, and the area of the region without ribs is considered to be smaller. However, if the ribs are provided symmetrically, the linearity of the region without the ribs tends to become longer, and the fins tend to deform along the linearity when heat is applied to the fins.

1 fin 1a one end (fin leading edge)
1b Other end 1c Plane portion 2 Flat tube (heat transfer tube)
2c Flat portion 3 First rib 3a Extended portion 3b Expanded portion 3c Reduced portion 4 Second rib 7 Inserted portion 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 Expansion device 108 Indoor unit 109 Indoor heat exchanger 110 Indoor fan motor 111 Indoor fans 112a, 112b Connection pipe

Claims (2)

a plurality of flat heat transfer tubes in which a refrigerant for exchanging heat with air flows;
a fin 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,
The fins are
an airflow upstream end and an airflow downstream end in the airflow direction;
an insertion portion formed from the downstream end of the airflow and in which the heat transfer tube is arranged;
a flat portion formed between the adjacent insertion portions;
a first rib formed above the insertion portion and protruding from the flat portion along the longitudinal direction of the insertion portion;
a second rib formed above the insertion portion so as to protrude from the flat portion on the downstream end side of the airflow along a direction perpendicular to the longitudinal direction of the insertion portion;
a third rib vertically above the first rib on the planar portion;
The first rib, the second rib, and the third rib are independent, and the rising end line of the first rib on the insertion section side and the rising end line of the second rib on the downstream end side of the air flow and an L-shaped condensed water flow path formed by intersecting a and a heat exchanger. An air conditioner comprising the heat exchanger according to claim 1 .

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