JP2014156990A - Heat exchanger of air conditioner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat exchanger of an air conditioner which can suppress flexure of a fin in the manufacturing, can secure drainage when using the heat exchanger as an evaporator and, further, improves the deterioration of efficiency of heat exchange by means of the cutting and raising for fin pitch adjustment.SOLUTION: A heat transfer part 23 which is a part between flat tubes 31 adjacent to each other on a fin 21 has one or more cutting and raising 26, 27 for fin pitch adjustment on each of windward side and leeward side, at least the cutting and raising 26 on the windward side is formed such that the cutting and raising surface lies along air passage direction, at least one rib 24 is provided on the windward side of the heat transfer part 23 of the fin 21, the fin 21 is protruded to the windward side with respect to the windward side edge of the flat tube 31, forms a drain part 28a continuing in a step direction, meanwhile, the leeward side edge of the fin 21 is located on the same position as the position of leeward side edge of the flat tube 31 and is not protruded to the leeward side. Therein, when a protrusion length of the drain part 28a of the fin 21 is X, the length in the longitudinal direction of the flat tube 31 is Y, the following relation is provided: 0.05≤X/Y≤0.4.

Description

  The present invention belongs to a heat exchanger of an air conditioner.

  Conventionally, a heat exchanger used in an outdoor unit of an air conditioner has a plurality of fins stacked at intervals so that air passes in the air passage direction, and is orthogonal to the plurality of fins. And a plurality of heat transfer tubes provided in a plurality of stages in a step direction perpendicular to the air passage direction. A circular tube or a flat tube is used as the heat transfer tube. When a circular tube is used, Karman vortices are generated on the leeward side, so the heat transfer performance is reduced. However, when a flat tube is used, the R on the windward side is smaller than that of the circular tube, and the Karman vortex is smaller than that of the circular tube. Is unlikely to occur. For this reason, a flat tube has the advantage that a heat transfer performance fall and an increase in ventilation resistance can be suppressed rather than a circular tube.

  Further, when manufacturing a heat exchanger using a circular pipe, a method is adopted in which the circular pipe and the fin are brought into close contact with each other by expanding the circular pipe after the circular pipe is inserted into the fin. On the other hand, when manufacturing a heat exchanger using a flat tube, the following method is adopted because the flat tube cannot be expanded like a circular tube. That is, after aligning multiple fins, a method is adopted in which a flat tube is inserted into a tube insertion part formed by cutting off the end of the fin in the air passage direction, and the flat tube and the fin are brought into close contact by brazing. doing.

  In a heat exchanger using this type of flat tube, a fin is cut and raised in order to prevent the fin from bending when aligning a plurality of fins (see Patent Document 1). This cut and raised portion also has a role of adjusting the interval between the fins when the cut and raised tip portion comes into contact with adjacent fins. Moreover, in patent document 1, when using a heat exchanger as an evaporator, in order to ensure the drainage property of the condensed water which generate | occur | produces on the surface of a fin, the windward end of a fin protrudes from a flat tube to the windward side, and a step is carried out. A drainage part continuous in the direction (vertical direction) is formed, and the drainage part is used as a drainage channel.

  By the way, in recent years, a heat exchanger for an outdoor unit is often bent and mounted in an L-shape or a U-shape in an outdoor unit housing from the viewpoint of miniaturization. However, since the flat tube has a larger moment of inertia in cross section than the circular tube, a load necessary for bending becomes large when the bent portion is formed by the heat exchanger using the flat tube.

  When such a large load is applied during the bending process, the bending load acts on the drainage portion protruding to the windward side from the heat transfer tube. In this case, if the strength of the fin is low, the fin collapse may occur. When the fin collapses, the air flow path is blocked, resulting in inconveniences such as reduced heat transfer performance of the heat exchanger, increased fan input due to increased ventilation resistance, and increased noise. For this reason, when manufacturing the flat tube heat exchanger which has a bending part, the intensity | strength of a fin is needed.

  Therefore, a technique for increasing the strength of the fin has been proposed conventionally, and in the part across the heat transfer portion formed between the flat tubes adjacent in the step direction in the fin and the drainage portion for ensuring drainage, There is a technique in which a rib with a protruding portion is formed (see, for example, Patent Document 2).

Japanese Patent No. 3264525 (second page, FIG. 1) JP 2012-154493 A (page 9, FIG. 5)

  In patent document 1, although the drainage is ensured by providing a drainage part, improvement of the fin strength with respect to bending is not examined.

  Further, in Patent Document 2, although a certain fin strength is improved by providing a rib, since the leeward side end of the fin protrudes downstream from the flat tube, the downstream protrusion is provided. The strength was lowered due to the part. For this reason, there is room for improvement in the certainty of the request for suppressing the bending of the fins during manufacturing.

  Moreover, in patent document 2, although the raising part for fin pitch adjustment is provided in the waste_water | drain part, the raising part is inclined and provided with respect to the air passage direction. For this reason, there existed a problem that the flow of air was inhibited, it became ventilation resistance, and the fall of heat exchange efficiency was caused.

  The present invention has been made in view of the above points, and can suppress the deflection of the fins at the time of manufacture, can ensure drainage when using the heat exchanger as an evaporator, and further cuts and raises the fin pitch. It aims at obtaining the heat exchanger of the air conditioner which can improve the fall of the heat exchange efficiency by.

  The heat exchanger of the air conditioner according to the present invention includes a plurality of fins stacked at intervals so that air passes in the air passing direction, and is inserted so as to be orthogonal to the plurality of fins, and a refrigerant is contained inside. A heat exchanging section that includes a plurality of flat tubes that pass through and are provided in a plurality of stages in a step direction perpendicular to the air passage direction, the heat exchanging section has a bent portion in the stacking direction, The heat transfer part, which is a part between the flat tubes adjacent to each other in the fin, is inserted into the tube insertion part provided at the leeward side end of the fin so that the major axis direction of the cross section is the air passage direction. Each of the windward side and the leeward side is provided with one or more fins for adjusting the pitch of the fin, and at least the windward side raises are arranged on the fin so that the cut-and-raised surface is along the air passage direction. One or more at least on the windward side of the heat transfer section The fins protrude from the leeward end of the flat tube to the leeward side to form a drainage section that is continuous in the step direction, while the leeward side end of the fin is leeward as the position of the leeward side end of the flat tube 0.05 ≦ X / Y ≦ 0.4, where X is the protruding length of the drainage part of the fin, and Y is the length in the long axis direction of the flat tube.

  According to the present invention, it is possible to suppress the bending of the fin at the time of manufacture, to ensure the drainability when the heat exchanger is used as an evaporator, and to further improve the decrease in heat exchange efficiency due to the fin pitch adjustment. It is possible to obtain a heat exchanger for an air conditioner that can be used.

It is a disassembled perspective view of the outdoor unit provided with the heat exchanger which concerns on Embodiment 1 of this invention. It is a perspective view of the heat exchanger of FIG. It is AA sectional drawing of FIG. FIG. 4 is a view showing a configuration in which ribs 25 are also provided on the leeward side in the modification of FIG. 3. It is an apparatus figure when the buckling strength of the heat exchanger of FIG. 1 is measured. It is a figure which shows three structural examples of the heat exchange part for comparing buckling strength. It is a figure showing the relationship between the waste_water | drain amount and X / Y in the heat exchanger provided with three rows of heat exchange parts shown in FIG. It is a figure showing the relationship between COP and X / Y in the heat exchanger provided with three rows of heat exchange parts shown in FIG. FIG. 4 is an explanatory diagram of the cutting and raising of FIG. 3. It is a figure which shows the relationship between pressure loss [Pa] and angle (alpha) [degree] when the angle (alpha) with respect to the air passage direction of the upwind cut-and-raised 26 is changed. It is a figure which shows the relationship between pressure loss [Pa] and angle (beta) [°] when angle (alpha) = 0 degree and angle (beta) with respect to the air passage direction of the cut-and-raised side 27 are changed. It is a longitudinal cross-sectional view of the heat exchange part of the heat exchanger which concerns on Embodiment 2 of this invention. It is a figure which shows the louver of FIG. It is the figure which showed the relationship between an external heat transfer rate and front surface speed. It is the partial front view which looked at the heat exchange part of the heat exchanger which concerns on Embodiment 3 of this invention from the air passage direction. It is a figure which shows the relationship between the heat transfer coefficient outside a tube and k in the heat exchanger of FIG. It is a longitudinal cross-sectional view of the heat exchange part of the heat exchanger which concerns on Embodiment 4 of this invention. It is a figure which shows the relationship between the heat transfer coefficient outside a tube and k in the heat exchanger of FIG. 19A is a diagram in which ribs 70 are provided in the configuration of the first embodiment shown in FIG. 4, and FIG. 19B is a diagram in which ribs 70 are provided in the configuration of the second embodiment shown in FIG. FIG. It is a figure which shows a top blowing type outdoor unit.

Embodiment 1 FIG.
FIG. 1 is an exploded perspective view of an outdoor unit provided with a heat exchanger according to Embodiment 1 of the present invention. FIG. 2 is a perspective view of the heat exchanger of FIG. In FIG. 1, the outdoor unit includes a heat exchanger 1, a fan 2, a compressor 3, and the like. The outdoor unit in FIG. 1 is a so-called side blowing type outdoor unit.

  The heat exchanger 1 has a plurality of (two in this case) heat exchange portions 11 arranged in a row direction that is an air passage direction indicated by an arrow in FIG. 2, and a plurality of rows of heat formed in an I-shape. The exchange part 11 is bent and formed into an L shape. Each heat exchange unit 11 is inserted perpendicularly to the plurality of fins 21 and perpendicular to the air passage direction, with a plurality of fins 21 stacked at intervals so that air passes in the air passage direction. And a plurality of flat tubes 31 provided in a plurality of stages in the step direction (vertical direction in FIG. 2). And the flat tube 31 is arrange | positioned at the fin 21 so that the major axis direction of the cross section may turn into an air passage direction, and is joined to the fin 21 by brazing. Note that the number of columns of the heat exchange unit 11 is not limited to two, and may be three or more. Further, the shape of the bent portion 12 of the heat exchanger 1 is not limited to the L shape, and may be a U shape. Moreover, although the heat exchange part 11 showed the structure of multiple rows here, this invention is not limited to multiple rows, It is good also as a 1 row structure.

FIG. 3 is a cross-sectional view taken along the line AA of FIG. Hereinafter, the detailed structure of the heat exchanger 1 is demonstrated using FIG.
The flat tube 31 is partitioned inside to form a plurality of passages 31a, and the refrigerant flows through the passages 31a. Further, a plurality of tube insertion portions 22 into which the flat tubes 31 are inserted are formed at predetermined intervals in the step direction (vertical direction in FIG. 3) at the leeward end of the fin 21. The tube insertion portion 22 is formed by an elongated cutout extending from the leeward end of the fin 21 to the leeward side, and a flat tube 31 is inserted into the tube insertion portion 22 from the leeward side.

  A rib 24 for increasing the strength of the fin 21 is formed on the windward side of the heat transfer portion 23 that is a portion between the adjacent tube insertion portions 22 in the fin 21. The rib 24 is configured by a protrusion that protrudes in the stacking direction (a direction orthogonal to the paper surface in FIG. 3). 3 shows a configuration in which the rib 24 is provided only on the leeward side of the heat transfer unit 23, the rib 25 may be further provided on the leeward side of the heat transfer unit 23 as shown in FIG.

  The drainage portion 28 a of the fin 21 is provided so as to protrude further to the windward side than the windward end of the flat tube 31. The drainage part 28a is continuous in the vertical direction, and functions as a drainage part for draining the condensed water generated on the surface of the fin 21 when the heat exchanger 1 is used as an evaporator. On the other hand, the leeward side end 28 b of the fin 21 is the same as the position of the leeward side end of the flat tube 31, and the fin 21 does not protrude further to the leeward side than the flat tube 31. 3 and 4 show the case where the windward side end portion 80 of the fin 21 is linear, it may not be linear as long as it is located on the left side of the left end of the flat tube 31.

  Cutouts 26 and 27 for adjusting the fin pitch are formed on the windward side of the fin 24 and on the leeward side of the heat transfer section 23, respectively. The cuts 26 and 27 are formed by cutting and raising the fins 21 into a substantially rectangular shape. That is, the upwind cut 26 is cut on three sides of the four sides of the rectangle (AB, BC, CD, DA in FIG. 3), and the other side (DA in this case) is bent at the fulcrum. It is formed by. The leeward cut-and-raised 27 is formed by cutting in three sides of the four sides of the rectangle (A1B1, B1C1, C1D1, and D1A1 in FIG. 3) and bending the remaining one side (here, D1A1) as a fulcrum. Is done. In addition, although the bending angle of the cut-and-raised portions 26 and 27 is a right angle here, it is not limited to a right angle.

  The fin pitch is adjusted (held) by the tip of the cut and raised portion coming into contact with the adjacent fin 21. That is, the cut and raised height = fin pitch.

  As shown in FIG. 1, when the heat exchanger 1 has the bending part 12, it is necessary to bend the whole heat exchanger. When the number of rows of the heat exchanger 1 is two or more, the number of machining steps can be reduced by bending them all at once. On the other hand, if each row is bent separately, the number of machining steps is increased, and the bending R needs to be changed for each row. Further, when the rows are combined, misalignment tends to occur. For this reason, it is preferable to perform bending at a time.

  However, when bending two or more rows of heat exchangers 1 at a time, as described above, if the strength of the fins 21 is low, fin collapse occurs. If it does so, the flow path of a wind will be obstruct | occluded and the problem of the increase in the fan input by the ventilation resistance increase, the noise increase, etc. will generate | occur | produce the heat exchanger 1. For this reason, the strength of the fins 21 is required to perform bending at a time.

FIG. 5 is an apparatus diagram when the buckling strength of the heat exchanger of FIG. 1 is measured.
Although the heat exchanger 1 is provided with two heat exchange parts 11 here, this buckling strength [N / m] is measured with respect to one heat exchange part 11. In the measurement, one side of both ends of the heat exchange unit 11 in the air passing direction is placed on the base 40, and a load is applied to the heat exchange unit 11 in the gravitational direction by the weight 41, and the load at which the fins 21 buckle is measured. Table 1 shows the results of performing this measurement for each heat exchanging portion 11 in FIGS. 6A to 6C and calculating the buckling strength. In FIG. 6 (b), the protruding length X of the drainage portion 28a in which the fin 21 protrudes to the windward side from the flat tube 31 is longer than that in FIG. 6 (a), and FIG. 21 shows a configuration in which both the windward side and the leeward side protrude from the flat tube 31.

  As shown in Table 1, when the fin 21 protrudes from the flat tube 31 on both the windward side and the leeward side (FIG. 6C), the buckling strength is the smallest, and the case where only the windward side protrudes is the seat. It can be seen that the buckling strength increases as the bending strength increases and the protruding length X (the protruding length of the drainage portion 28a) X decreases.

  Next, the relationship between the value obtained by dividing the protruding length X of the drainage portion 28a by the length Y of the flat tube 31 in the long axis direction (= X / Y) and the buckling strength will be examined.

  When the buckling of the fins 21 when the three-row simultaneous bending was performed on the heat exchanger 1 having three rows of the heat exchanging portions 11 shown in FIG. 3 was examined by the following method, the following results were obtained. . That is, three rows were bent simultaneously by changing the protruding length X of the drainage portion 28a, and it was examined whether the fins 21 were buckled. As a result, no buckling occurred when X / Y ≦ 0.4.

Next, the relationship between the amount of drainage [g / s] and X / Y will be examined.
When the protrusion length X of the fin 21 is short, the condensed water generated in the flat tube 31 and the fin 21 cannot be drained when the outdoor unit is used as an evaporator during the heating operation, and the condensed water is discharged to the flat tube 31 and the fin 21. Retained. In this case, frost is formed at the holding portion and air does not flow, and the performance of the heat exchanger 1 is deteriorated. That is, there is a relationship between the protrusion length X and the amount of drainage.

FIG. 7 is a diagram illustrating the relationship between the amount of drainage and X / Y in a heat exchanger including three rows of heat exchange units illustrated in FIG.
From FIG. 7, it can be seen that when X / Y <0.05, the amount of drainage increases as X becomes longer, and when X / Y ≧ 0.05, the amount of drainage becomes constant.

Next, the relationship between COP and X / Y will be examined.
FIG. 8 is a diagram illustrating a relationship between COP and X / Y in a heat exchanger including three rows of heat exchange units illustrated in FIG. 3.
From FIG. 8, when X / Y <0.05, COP increases as X becomes longer. When X / Y ≧ 0.05, COP increases more slowly as X increases. The reason why COP increases more gradually as X is larger when X / Y ≧ 0.05 is that when X becomes longer, the heat transfer area of the fins 21 increases and the heat transfer amount of the heat exchanger 1 increases. .

  From the above FIG.7 and FIG.8, when X / Y> = 0.05, drainage is ensured and COP improves.

  Therefore, when 0.05 ≦ X / Y ≦ 0.4, the buckling of the fins 21 can be prevented and the drainage can be ensured.

  As shown in FIG. 4, the same result is obtained in a heat exchanger having three rows of heat exchanging portions 11 having ribs 25 on the leeward side, when 0.05 ≦ X / Y ≦ 0.4. The buckling of the fin 21 can be prevented and the drainage can be ensured. As a result of obtaining the probability of occurrence of buckling of the fins 21 in the heat exchanger 1 having three rows of the heat exchanging portions 11 shown in FIG. 3 and FIG. 4, they are 0.9% and 0.4%, respectively. The probability of the buckling of the fin 21 occurring in the heat exchange unit 11 shown in 4 can be reduced.

  FIG. 9 is an explanatory diagram of the cut-and-raised portion of FIG. FIG. 10 is a diagram showing the relationship between the pressure loss [Pa] and the angle α [°] when the angle α with respect to the air passing direction of the windward cut-and-raise 26 is changed. FIG. 10 shows the relationship between the pressure loss [Pa] and the angle α [°] in the configuration in which there is no leeward cut and raised portion 27 and the fin pitch is adjusted by the leeward cut and raised portion 26. Note that the height of the cut-and-raised 26 is equal to the fin pitch.

  FIG. 10 shows that when the angle α = 0 °, that is, when the cut-and-raised surface of the cut-and-raised 26 is along the air passage direction, the ventilation resistance is minimized and the pressure loss is the smallest. And, as the angle α increases, the cut-and-raised 26 closes the flow path, so that vortices are likely to occur in the wake and pressure loss increases.

  FIG. 11 is a diagram showing the relationship between the pressure loss [Pa] and the angle β [°] when the angle α = 0 ° and the angle β of the leeward cut and raised 27 with respect to the air passage direction is changed. Also in this case, when the angle β = 0 °, the ventilation resistance is minimized and the pressure loss is minimized. However, the change in pressure loss due to the angle β is smaller than the change in pressure loss due to the angle α. This is because the rib 25 on the windward side of the cut-and-raised 27 has ventilation resistance, so that a vortex is generated behind the rib 25 and flows into the cut-and-raised 27. When α = 0 °, the rib 26 in FIG. 3 may be disposed on the right side of the left end of the flat tube 31 when the rib 26 provides flow resistance for the condensed water flowing through the drainage channel.

  In the case where there is only one cut and raised, the fin 21 is bent during manufacturing, and the fin pitch varies. For this reason, in the first embodiment, one or more cuts are provided on both the windward side and the leeward side, and two or more points are required in total.

  As described above, according to the first embodiment, the buckling strength of the fins 21 can be increased by providing the characteristic configurations shown in the following (1) to (4). The bending of the fin 21 at the time of manufacture can be suppressed. Moreover, the drainage property when using the heat exchanger 1 as an evaporator can be ensured.

(1) One or more fin pitch adjustment cuts 26 and 27 are provided on the windward side and the leeward side of the heat transfer section 23 of the fin 21, and at least the windward cut and raised 26 has a cut and raised surface. It is formed along the long axis direction of the flat tube 31.
(2) At least the windward side of the fin 21 protrudes to the windward side of the flat tube 31 to form a drainage portion 28a continuous in the step direction (vertical direction), and the leeward side end 28b of the fin 21 is flat. It is the structure which does not protrude to the leeward side rather than the pipe | tube 31. FIG.
(3) One or more ribs 24 are provided on the windward side of the heat transfer section 23 of the fin 21.
(4) When the projecting length of the drainage portion 28a is X and the length of the flat tube 31 in the major axis direction is Y, 0.05 ≦ X / Y ≦ 0.4.

  Further, according to the first embodiment, the buckling strength of the fins 21 can be increased in the case of one row as well as in the case where the number of rows of the heat exchanging portions 11 is a plurality of rows. The bending of the fin 21 at the time can be suppressed.

Embodiment 2. FIG.
In the second embodiment, the fin 21 of the first embodiment is further provided with a louver 50. In the following, the second embodiment will be described focusing on the differences from the first embodiment.

FIG. 12 is a longitudinal sectional view of a heat exchange part of a heat exchanger according to Embodiment 2 of the present invention. 13 is a view showing the louver 50 of FIG. 12, in which FIG. 13 (a) is an AA cross-sectional view of FIG. 12, and FIG. 13 (b) is a BB cross-sectional view of FIG.
The second embodiment has a configuration in which a plurality of louvers 50 extending in the step direction are arranged in parallel in the air passage direction between the rib 24 and the rib 25 of the fin 21 of the first embodiment shown in FIG. Yes. The louver 50 includes leg portions 51 that are cut and raised from the fins 21 and inclined with respect to the fins 21, and cut and raised portions 52 that are parallel to the fins 21. By providing the louver 50 in this manner, air turbulence occurs and the turbulent heat transfer coefficient can be improved. Here, a configuration in which a plurality of louvers 50 are provided is shown, but it is sufficient that at least one louver 50 is provided.

FIG. 14 is a diagram showing the relationship between the external heat transfer coefficient and the front speed. In FIG. 14, the thin line indicates the case of the heat exchanger 1 without a louver shown in FIG. 4, and the dark line indicates the case of the heat exchanger 1 with a louver shown in FIG.
FIG. 14 shows that the configuration in which the fins 21 are provided with the louvers 50 has a higher external heat transfer coefficient [W / m ² K] at any front speed [m / s].

  As described above, according to the second embodiment, the effect similar to that of the first embodiment is obtained, and the louver 50 is provided between the rib 24 and the rib 25, thereby improving the heat transfer coefficient outside the tube. Can do.

Embodiment 3 FIG.
The third embodiment defines the length in the stacking direction of the louver 50 of the second embodiment. In the following, the third embodiment will be described focusing on the differences from the second embodiment.

FIG. 15 is a partial front view of the heat exchange unit of the heat exchanger according to Embodiment 3 of the present invention as viewed from the air passing direction.
The height of the rib 24 is 0.3 times the fin pitch fp, and the length H of the louvers 50 in the stacking direction is H = k × fp. In this case, the relationship between the external heat transfer coefficient and k is as shown in FIG.

FIG. 16 is a diagram showing the relationship between the heat transfer coefficient outside the tube and k in the heat exchanger of FIG.
From FIG. 16, when k ≦ 0.3, that is, when the louver 50 is equal to or shorter than the length of the rib 24, the external heat transfer coefficient [W / m ² K] does not change. However, when k> 0.3, that is, when the louver 50 is longer than the length of the rib 24, the heat transfer coefficient outside the tube increases. This is because the rib 24 is on the windward side of the louver 50, so when k ≦ 0.3, air flows into the louver 50 in a vortex state, and the velocity of the vortex is small. For this reason, the louver 50 does not contribute to the heat transfer coefficient outside the tube. On the other hand, when k> 0.3, the louver 50 has a height higher than that of the rib 24. Therefore, turbulence occurs in the air flowing into the louver 50, and the turbulent heat transfer coefficient is improved.

  As described above, according to the third embodiment, the effect similar to that of the second embodiment is obtained, and the length of the louver 50 in the stacking direction is set to be longer than the length of the rib 24 in the same direction. The transmission rate can be improved.

Embodiment 4 FIG.
The fourth embodiment defines the length in the step direction of the louver 50 of the second embodiment. Hereinafter, the difference between the fourth embodiment and the second embodiment will be mainly described.

FIG. 17 is a longitudinal sectional view of a heat exchange part of a heat exchanger according to Embodiment 4 of the present invention.
The length L1 in the step direction of the ribs 24 and 25 and the length L2 in the step direction of the longest louver 50 among the plurality of louvers 50 have a relationship of L2 = k × L1. Here, L1 is the maximum length at which the flat portion 60 between the ribs 24 and 25 and the flat tube 31 is not bent. The relationship between the heat transfer coefficient outside the tube and k when the height of the ribs 24 and 25 is 0.3 times the fin pitch and the height of the louver 50 is 0.6 times the fin pitch is shown in FIG. become that way.

18 is a diagram showing the relationship between the heat transfer coefficient outside the tube and k in the heat exchanger of FIG.
From FIG. 18, the larger the k, the larger the extra-tube heat transfer coefficient [W / m ² K], and the maximum when k = 1. This is because turbulent heat transfer by the louver 50 is promoted as k increases, and the heat transfer coefficient outside the tube increases.

  As described above, according to the fourth embodiment, the effects similar to those of the second embodiment are obtained, and the lengths of the ribs 24, 25 and the louver 50 in the step direction are made substantially equal to each other. The transmission rate can be improved. In addition, although the example which prescribes | regulates the length of the louver 50 in Embodiment 2 was demonstrated here, it is good also as a structure which prescribes | regulates the length of the louver 50 in Embodiment 3. FIG. In this case, the external heat transfer coefficient can be further improved.

Embodiment 5 FIG.
In addition to the configurations of the first to fourth embodiments, ribs 70 may be further provided on both sides in the step direction of the fins 26 cut and raised.

  19A is a diagram in which ribs 70 are provided in the configuration of the first embodiment shown in FIG. 4, and FIG. 19B is a diagram in which ribs 70 are provided in the configuration of the second embodiment shown in FIG. The figure is shown.

  By comprising in this way, in addition to each effect of each Embodiment 1-4, the intensity | strength of the fin 21 can further be raised with the rib 70, and the bending of the fin 21 at the time of manufacture can further be suppressed. Heat exchanger can be obtained.

  In the above, the outdoor unit is an example of a so-called horizontal blow type, but as shown in FIG. 20, the heat exchanger of the present invention can also be applied to an up blow type outdoor unit. In this case, the same effect as described above can be obtained.

  DESCRIPTION OF SYMBOLS 1 Heat exchanger, 2 Fan, 3 Compressor, 11 Heat exchange part, 12 Bending part, 21 Fin, 22 Pipe insertion part, 23 Heat transfer part, 24 Rib, 25 Rib, 26 Cut and raise, 27 Cut and raise, 28a Waste water Part, 28b leeward side end, 31 flat tube, 31a passage, 40 base, 41 weight, 50 louvers, 51 leg part, 52 cut-and-raised part, 60 flat part, 70 rib, 80 fin leeward side end part.

Claims (6)

A plurality of fins stacked at intervals so that air passes in the air passage direction, and inserted so as to be orthogonal to the plurality of fins, the refrigerant passes through the inside and is perpendicular to the air passage direction. A heat exchanging portion provided with a plurality of flat tubes provided in a plurality of stages in the step direction, the heat exchanging portion has a bent portion in the stacking direction,
The flat tube is inserted into a tube insertion portion provided at the leeward side end of the fin so that the major axis direction of the cross section is the air passage direction,
The heat transfer part, which is a portion between the flat tubes adjacent to each other in the fins, includes one or more fin pitch adjustment cuts and raiseds on each of the windward side and the leeward side,
At least the cut-and-raised portion on the windward side is disposed on the fin so that the cut-and-raised surface is along the air passing direction.
One or more ribs on at least the windward side of the heat transfer portion of the fin;
The fin protrudes further to the windward side than the windward end of the flat tube and forms a drainage part continuous in the step direction, while the leeward side end of the fin is the same as the position of the leeward side end of the flat tube A structure that does not protrude to the leeward side,
Air conditioning, wherein 0.05 ≦ X / Y ≦ 0.4, where X is the protruding length of the drainage portion of the fin and Y is the length of the flat tube in the long axis direction. Machine heat exchanger.   The fin includes a louver extending in a step direction between the ribs adjacent to each other in the air passage direction, the louver being cut and raised from the fin and inclined with respect to the fin, and the fin The heat exchanger for an air conditioner according to claim 1, further comprising:   The heat exchanger for an air conditioner according to claim 2, wherein a length of the louver in the stacking direction is longer than a length of the rib in the stacking direction.   The heat exchanger for an air conditioner according to claim 2 or 3, wherein the lengths of the ribs and the louvers in the step direction are substantially equal.   The heat exchanger for an air conditioner according to any one of claims 1 to 4, wherein ribs are provided on both sides of the fin in the step direction of the cut and raised on the windward side.   The heat exchanger for an air conditioner according to any one of claims 1 to 5, wherein the heat exchange section includes a plurality of rows in a row direction that is the air passage direction.

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