JP2010261638A - Indoor unit of air conditioner, heat exchanger used in the same, and method of manufacturing heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger of high heat transferring performance and its manufacturing method at low costs, and to provide an indoor unit of an air conditioner having the heat exchanger of high heat transferring performance at low costs. <P>SOLUTION: This cross fin-tube type heat exchanger is constituted by fitting and inserting a plurality of heat transfer tubes 7 to a plurality of sheets of fins 8 arranged in parallel with each other in the thickness direction at required intervals. Each of the fins 8 has a curved section at least on a part in the longitudinal direction, and the curved sections have burring holes 9 in a plurality of rows in the width direction along the curved side and a plurality of stages in the longitudinal direction. Each burring hole 9 formed on the curved section is positioned so that straight lines respectively connecting the burring holes 9 of the stages corresponding to the rows are approximately in parallel with each other in all of the stages. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an indoor unit of an air conditioner, a heat exchanger used therefor, and a method for manufacturing the heat exchanger, and more particularly, to a configuration of a fin constituting the heat exchanger and a method for manufacturing the fin.

  In general, an air conditioner is composed of an outdoor unit and an indoor unit connected via a refrigerant pipe and electric wiring. The outdoor unit houses a compressor, an outdoor heat exchanger, and an expansion valve, and the indoor unit houses an indoor heat exchanger and a cross-flow fan. The indoor heat exchanger is disposed so as to surround a part of the peripheral surface of the cross-flow fan, and performs heat exchange between the refrigerant and the indoor air. As this type of indoor heat exchanger, a predetermined interval is used. 2. Description of the Related Art A cross fin tube type heat exchanger in which a heat transfer tube is inserted and inserted into a large number of fins arranged in parallel with a gap therebetween is conventionally known. Further, as a fin used in this type of indoor heat exchanger, at least a portion disposed on the front side of the cross-flow fan is curved in a convex arc shape when viewed from the side of the indoor unit, 2. Description of the Related Art Conventionally, bar link holes for inserting heat transfer tubes are arranged in a staggered manner with respect to the air inflow direction (see, for example, Patent Document 1).

  The cross fin tube type heat exchanger is easier to manufacture fins and has a much larger area of scrap material compared to heat exchangers that have fins formed by alternately diffracting strip-shaped fin materials. Advantages such as being able to be reduced. In addition, when the heat transfer tubes are arranged in a staggered manner, the downstream tube row is not arranged in the dead water region of the tube row arranged on the upstream side in the air inflow direction, so that high heat transfer performance can be ensured.

  On the other hand, a method for manufacturing a fin having a curved shape is conventionally known (see, for example, Patent Document 2) having the following procedure. (1) A large number of burring holes for heat transfer tube insertion having a predetermined arrangement pattern are formed in the length direction of the fin material formed in a belt shape using a burring hole forming mold. (2) Cut and raised are formed in a predetermined arrangement pattern around the burring holes established in the previous step using a cut and raised mold. (3) Cut the short side portion of the fin material to adjust the length of the fin to be manufactured. (4) The fin material is cut at regular intervals in the length direction, and the fin formed with the burring hole for inserting and transferring the heat transfer tube for each set is cut out.

JP 9-42699 A Japanese Patent Laid-Open No. 10-54685

  By the way, because air conditioners have a cooling capacity that is a guide for the size of the room, air conditioner manufacturers produce a variety of air conditioners that fit into different rooms of different sizes. is doing. The heat transfer area of the required heat exchanger also changes depending on the cooling capacity of the air conditioner, so various fins with different numbers of rows of bar link holes arranged in the width direction of the fins depending on the model to be produced Need to manufacture.

  In this case, in order to manufacture various fins having different numbers of rows of bar link holes, preparing a plurality of burring hole forming dies and cut and raised forming dies not only increases the equipment cost but also increases the fins. This is not preferable because the manufacturing process becomes complicated. Therefore, it is desired to produce various fins having different numbers of rows of bar link holes using a set of burring forming mold and cut and raised forming mold.

  However, in the fin in which the heat transfer tubes are arranged in a staggered manner with respect to the air inflow direction, the opening position of the burring hole opened on the upstream side in the air inflow direction and the opening position of the burring hole opened on the downstream side thereof Therefore, as shown in FIG. 8, when the fin 8 having the number of rows of the bar link holes 9 of “3” is cut out from the fin material 11 in which the burring holes 9 having two rows as one set are opened, Unnecessary bar link holes 9a are opened in the fins 8, and it is impossible to manufacture appropriate fins that do not have unnecessary bar link holes 9a. Such an inconvenience also occurs when the fins 8 having the number of rows of the bar link holes 9 of “4” or more are cut out from the fin material 11 in which the burring holes 9 having two rows as one set are opened.

  If the burring holes in each step and each row are arranged so that the straight lines connecting the bar link holes in each row arranged in the length direction of the fins are parallel to each other, the number of rows of burring holes Regardless, an appropriate fin having no unnecessary burring hole can be cut out from the fin material. However, according to this method, the heat transfer performance is deteriorated because the downstream heat transfer tube is disposed in the dead water area of the heat transfer tube disposed upstream in the air inflow direction.

  The present invention has been made to solve the problems of the prior art, and its object is to provide a heat exchanger that is inexpensive and has good heat transfer performance, a manufacturing method thereof, and a heat exchanger that is inexpensive and has high heat transfer performance. The object is to provide an indoor unit of an air conditioner equipped with a good heat exchanger.

  In order to solve the above-mentioned problems, the present invention relates to a heat exchanger of a cross fin tube type in which a plurality of heat transfer tubes are inserted and inserted into a plurality of fins arranged in parallel in the thickness direction with a predetermined interval therebetween. In the heat exchanger, the fin has a curved portion in at least a part of the length direction, and the curved portion has a plurality of rows in the width direction and a plurality of burrings in the length direction along the curved side. A hole is established, and each burring hole established in the curved portion is arranged such that straight lines connecting the burring holes of corresponding stages in each row are substantially parallel in all stages. Made the configuration.

  The fins used in the cross fin tube type heat exchanger are burring holes corresponding to the number of rows corresponding to the cooling capacity of the air conditioner to be manufactured from the strip-shaped fin material in which the burring holes are opened in the required arrangement. It is produced by cutting out the fins. In this case, at least a part of the length direction has a curved portion, and the curved portion has a plurality of rows in the width direction and a plurality of burring holes in the length direction along the curved side. As shown in FIG. 5, each burring hole opened in the curved portion is arranged so that the straight lines connecting the corresponding burring holes in each row are substantially parallel to each other, as shown in FIG. In this stage, the opening positions of the burring holes of each step arranged in the width direction of the fin material can be oriented parallel to the side of the belt-like fin material and arranged in the length direction of the fin material. The opening pitch of the burring holes in each row can be made equal. Therefore, each row of burring holes can be continuously opened by using one type of burring hole forming mold, and even when various fins having different numbers of rows of burring holes are cut out, an extra burring hole is provided. There is no manufacturing of fins having the necessary burring holes. Further, when the burring holes are arranged in this manner, at least both ends excluding the central region in the longitudinal direction of the curved portion, the burring holes and thus the heat transfer tubes can be arranged in a staggered manner with respect to the air inflow direction. Thus, a heat exchanger with good heat transfer performance can be obtained.

  In the heat exchanger, the step pitch of each burring hole established in the length direction of the fin is such that the burring holes of each step arranged in the row direction with respect to the air inflow direction. The step pitch in the substantially parallel portion is set to be larger than the step pitch in the portion where the burring holes of each step arranged in the row direction with respect to the air inflow direction are not substantially parallel.

  When the burring holes are arranged as described above, in the central region in the longitudinal direction of the curved portion, the burring holes of each stage arranged in the column direction with respect to the air inflow direction are substantially parallel, and the air flow A dead water area tends to occur on the downstream side of the curved portion, and at both ends in the length direction of the curved portion, the burring holes of each stage arranged in a row direction with respect to the air inflow direction are staggered, and the dead water area is It becomes difficult to occur. Therefore, if the step pitch of the burring holes established in the central portion in the length direction of the curved portion where a dead water area is likely to be generated is made larger than the others, the dead water area formed on the downstream side of the air flow is reduced. Can alleviate the adverse effects.

  Further, the present invention is configured such that a cut-and-raised portion for adjusting the wind direction is formed between the burring hole forming positions of the fins with respect to the heat exchanger.

  According to such a configuration, the air flow direction across the fin can be adjusted by the cut-and-raised portion, so that, for example, even in the central region in the length direction of the curved portion where a dead water area is likely to be generated, the adverse effect can be almost eliminated. The heat transfer performance of the heat exchanger can be increased.

  Further, the present invention relates to a heat exchanger, wherein the cut-and-raised portion for adjusting the wind direction is longer than the cut-and-raised portion arranged on the leeward side of the cut-and-raised portion. It was configured to make the direction longer.

  According to such a configuration, since the adjustment of the air flow direction on the leeward side can be facilitated, the occurrence of dead water areas on the leeward side that are more likely to occur than on the leeward side can be prevented, and the heat transfer performance of the heat exchanger can be improved. it can.

  In the heat exchanger, the front fin is folded back from the middle in the length direction, and the entire planar shape is formed in a substantially V shape.

  According to this configuration, the upper part of the fin formed in a substantially V shape surrounds the upper part of the circumferential surface of the cross-flow fan accommodated in the indoor unit, and the front part of the fin formed in a substantially V shape has the indoor unit. Since the front part of the peripheral surface of the once-through fan accommodated in the inside can be surrounded, the heat transfer performance of the heat exchanger can be improved, and the fin can be formed from one member. Manufacture is easy and low cost.

  Furthermore, the present invention relates to a method of manufacturing a heat exchanger, a step of opening a burring hole for inserting a heat transfer tube in a predetermined arrangement in a strip-shaped fin material, and a predetermined around the burring hole opened in the previous step The process of forming the cut and raised part by arrangement, the process of adjusting the length of the fin by cutting the short side portion of the fin material, and the required burring hole and the cut and raised part by cutting the strip-shaped fin material in the length direction In the heat exchanger manufacturing method including the step of cutting the fin formed with, in the step of opening a burring hole for heat transfer tube insertion in a predetermined arrangement in the band-shaped fin material, in the width direction of the fin material The burring hole opening position and the cut-and-raised portion forming position of each stage to be arranged are oriented parallel to the side of the strip-shaped fin material and arranged in the length direction of the fin material. The opening pitch of the burring holes in the row and the formation pitch of the cut and raised portions are equal pitches, and the opening position of the burring holes and the formation position of the cut and raised portions in each row arranged in the length direction of these fin materials Is configured to bend in the length direction of the fin material.

  According to such a configuration, the opening positions of the burring holes of each step arranged in the width direction of the fin material can be oriented parallel to the side of the strip-shaped fin material, and arranged in the length direction of the fin material. Since the opening pitch of the burring holes in each row can be made equal, the burring holes in each row can be continuously opened using one type of burring hole forming mold, and the end material Generation | occurrence | production can be eliminated and manufacture of a fin can be made easy and low-cost.

  In addition, the present invention relates to an indoor unit of an air conditioner, and in the indoor unit of an air conditioner that houses an indoor heat exchanger and a cross-flow fan, the indoor heat exchanger is arranged in a thickness direction at a predetermined interval. A heat exchanger of a cross fin tube type in which a plurality of heat transfer tubes are fitted into a plurality of fins arranged in parallel, wherein the fin has a curved portion at least in a length direction, and the curved The section has a plurality of rows of burring holes in the width direction and a plurality of stages in the length direction along the curved side, and each of the burring holes formed in the bending section corresponds to each row. A straight line connecting the burring holes of the steps is arranged so as to be substantially parallel in all steps.

  According to such a configuration, it is possible to easily manufacture the fins at a low cost, and thus it is possible to reduce the cost and improve the performance of the indoor unit of the air conditioner.

  In the heat exchanger according to the present invention, the burring holes of each example and each stage opened in the curved portion of the fin are arranged so that the straight line connecting the corresponding stage burring holes in each row is substantially parallel in all stages. Since it is arranged, it is possible to open burring holes that can accommodate various fins with different numbers of rows using one type of burring hole forming mold when opening burring holes for fin materials. Manufacturing can be facilitated and the manufacturing cost can be reduced. Also, at least at both ends of the fin excluding the central region in the length direction of the curved portion, the burring holes and thus the heat transfer tubes can be arranged in a staggered manner with respect to the air inflow direction, so that the heat transfer performance is good. Can be.

  The method for manufacturing a heat exchanger according to the present invention is such that the opening positions of the burring holes at each stage arranged in the width direction of the fin material are oriented parallel to the side of the strip-shaped fin material and the length of the fin material is Since the opening pitch of the burring holes in each row arranged in the direction is made equal, various fins with different numbers of rows of burring holes opened in the fins are manufactured using one burring hole forming mold. In addition, it is possible to eliminate the generation of the end material, and it is possible to manufacture the fin easily and at low cost.

  Since the indoor unit of the air conditioner according to the present invention manufactures a heat exchanger using fins that are inexpensive and have good heat transfer performance, low cost and high performance can be achieved.

It is sectional drawing of the air conditioner indoor unit which concerns on Example 1. FIG. It is an enlarged view of the fin center part of the heat exchanger which concerns on Example 1. FIG. It is a perspective view which shows the 1st example of the cut-and-raised part formed in the fin of the heat exchanger which concerns on Example 1. FIG. It is a perspective view which shows the 2nd example of the cut-and-raised part formed in the fin of the heat exchanger which concerns on Example 1. FIG. FIG. 6 is an explanatory diagram of a method for manufacturing the fin according to the first embodiment. It is sectional drawing of the indoor unit of the air conditioner which concerns on Example 2. FIG. It is an enlarged view of the fin center part of the heat exchanger which concerns on Example 2. FIG. It is a top view of the fin which shows the problem of a prior art.

  Hereinafter, an indoor unit of an air conditioner according to the present invention will be described with reference to the accompanying drawings.

  As shown in FIG. 1, the indoor unit of an air conditioner according to the first embodiment includes a housing 1 having an air suction port 2 on the front surface and an upper surface and an air outlet 4 on the lower surface. Cross-flow fan 3 housed in body 1, front-side heat exchanger 5 disposed inside casing 1 so as to surround the front side of cross-flow fan 3, and casing so as to surround the back side of cross-flow fan 3 It is mainly comprised from the back side heat exchanger 6 arrange | positioned inside the body 1. FIG.

  The front-side heat exchanger 5 and the back-side heat exchanger 6 are cross fin tube type in which a plurality of heat transfer tubes 7 are inserted into a plurality of fins 8 arranged in parallel in the thickness direction at a predetermined interval. It is a heat exchanger. The fins 8 for the front-side heat exchanger 5 and the fins 8 for the back-side heat exchanger 6 are integrally formed, and the entire planar shape is substantially V-shaped by folding back from the middle in the length direction. Is formed. According to such a configuration, since the fin 8 can be configured from one member, the heat exchanger can be manufactured easily and at low cost.

  The fins 8 of the front-side heat exchanger 5 are curved in a direction in which the central portion protrudes to the front of the housing 1, and the curved portion has three rows in the width direction along the curved side. There are 13 burring holes 9 in the direction. These burring holes 9 are arranged so that the straight lines connecting the corresponding burring holes 9 in each row are substantially parallel to each other. Note that the step pitch of the burring holes 9 in each step is such that the step pitch L in the central portion B in the longitudinal direction of the fins 8 constituting the front side heat exchanger 5 is the step pitch L ′ in the upper portion A and the lower portion C. It is set to be wider. A plurality of heat transfer tubes 7 are fitted in each of these burring holes 9, and each heat transfer tube 7 is connected at both ends of the front side heat exchanger 5, and the refrigerant flows through this, Heat exchange between the inflowing air and the refrigerant is performed via the heat transfer tube 7.

  As shown in FIG. 2, a portion of the fin 8 that does not have the burring hole 9 (this is referred to as a “plate portion” in this specification) is inserted into the front side heat exchanger 5 from the front edge portion of the fin 8. A cut-and-raised part 10 is formed for adjusting the wind direction of the inflowing indoor air and applying it to the heat transfer tube 7. The orientation of the cut-and-raised portion 10 formed in each part of the upper part A, the central part B, and the lower part C of the fin 8 is parallel. As shown in FIG. 3, the cut and raised portion 10 can be formed by making a cut at both ends on the long side and then extruding the intermediate portion into a convex shape. Alternatively, as shown in FIG. Cuts can be made at both ends on the side, and the middle part can be extruded in a convex shape, with the nails raised on the short side. The cut-and-raised part 10 in FIG. 4 is not configured to change the inflow air on the surface like the cut-and-raised part 10 in FIG. 3, so the efficiency is slightly reduced, but the ventilation resistance is lower than the plate part without the cut and raised 10. Since the height can be increased, the inflow air can be deflected. In addition, it can also be set as the shape of a corrugated corrugated fin without corrugation. Thus, by forming the cut-and-raised portion 10 parallel to the plate portion, a continuous flow path having the same flow direction from the first row to the third row can be formed in the front-side heat exchanger 5. .

  Next, the manufacturing process of the fin 8 applied to the front side heat exchanger 5 will be described in the order of the manufacturing process with reference to FIG.

1. Burring process A burring hole 9 for inserting a heat transfer tube is formed in a fin material P made of a wide strip-shaped thin plate by a burring hole forming mold (not shown). In this case, as shown in FIG. 5, the opening positions of the burring holes 9 and the formation positions of the cut-and-raised portions 10 arranged in the width direction of the fin material P are defined with respect to the side of the strip-shaped fin material P. The opening pitch of the burring holes 9 and the formation pitch of the cut-and-raised portions 10 in each row arranged in the length direction of the fin material P are set to be equal pitches and are arranged in the length direction of the fin material P. The opening positions of the burring holes 9 in each row and the formation positions of the cut-and-raised portions 10 are curved in the length direction of the fin material P.

2. Cut and Raise Processing Cut and raised portions 10 are formed in a predetermined arrangement pattern around the burring holes 9 provided in the previous process by a not-shown cut and raised forming mold.

3. Side cut process The short side part of a processing range is cut, and the length of the fin 8 of the front side heat exchanger 5 is adjusted. In this process, an unnecessary portion in the short side direction of the wide fin material P is cut off using an apparatus such as a cutter.

4). Cut-off process The fin material P is intermittently sent to a cutting machine (not shown) to cut out the fins 8 having a required number of rows in a curved shape. As is apparent from FIG. 5, in this example, the burring holes 9 and the cut-and-raised portions 10 are formed in the same arrangement for each row of the fin material P, so that each row is independent of the number of rows of fins 8 to be cut. In addition, the fins 8 having the same arrangement of the burring holes 9 and the cut-and-raised portions 10 in the respective stages are cut out, so that the burring holes 9 and the cut-and-raised portions 10 are not excessively and deficient. Therefore, the burring hole 9 can be opened using the same burring hole forming mold regardless of the number of rows of fins 8 to be cut out, and the cut and raised portion 10 can be formed using the same cutting and forming mold. Thus, the fin 8 can be manufactured efficiently and at low cost.

  The heat exchanger of the present embodiment uses the same burring forming die and cut-and-raising forming die, even when the number of rows is changed, in addition to the advantages such as omission of the bending step mentioned in the prior art. Therefore, it becomes possible to manufacture the fins 8 of the front side heat exchanger 5 with different numbers of rows in one line, and it is possible to provide an inexpensive heat exchanger by reducing the cost of creating a mold and the cost of increasing the manufacturing line. Become.

  Next, the effect of the indoor unit according to the present embodiment configured as described above will be described with reference to FIGS. 1 and 2. When the operation of the air conditioner is started, the cross-flow fan 3 starts to rotate and the room air is taken in from the suction port 2. The room air passes through the front-side heat exchanger 5 and the back-side heat exchanger 6, and exchanges heat with the refrigerant through the heat transfer tube 7 during this time. At this time, the air flowing into the heat exchanger flows through the flow path that minimizes the ventilation resistance when passing through the fins 8 of the front heat exchanger. Accordingly, the inflowing air flows perpendicularly to the front edges of the fins 8 of the front side heat exchanger, passes through the fins 8 of the front side heat exchanger, and then goes to the once-through fan 3.

  Here, the arrangement of the heat transfer tubes 7 arranged on the fins 8 of the front-side heat exchanger 5 includes a portion that does not become a staggered arrangement in the air inflow direction. In other words, the staggered arrangement is that the straight line connecting the heat transfer tubes at the same stage is not perpendicular to the row direction of the fins 8 of the front side heat exchanger, and the upper part of the fins 8 of the front side heat exchanger A and lower part C. On the other hand, the staggered arrangement is that the straight line connecting the heat transfer tubes as described above is perpendicular to the row direction of the fins 8 of the front side heat exchanger, and the fins 8 of the front side heat exchanger 5 are not. Central portion B. In the upper part A and the lower part C that are arranged in a staggered manner, the heat transfer tube 7 arranged on the leeward side does not fall within the dead water area of the heat transfer tube 7 on the leeward side, and the heat transfer performance is also lowered by the manufacturing method of this embodiment. Does not occur.

  On the other hand, for the central portion B that is not in a staggered arrangement, the heat transfer performance is prevented from being lowered by the cut-and-raised portions 10 provided on the fins 8 of the front-side heat exchanger 5. As shown in FIG. 2, in this embodiment, a plurality of cut and raised portions 10 having an inclination with respect to the column direction are arranged in parallel with the cut and raised portions 10 provided in adjacent rows so as to be equally spaced. Has been. Thereby, since the long flow path which continues from the 1st row to the 3rd row is formed in the fin 8 of the front side heat exchanger, the inflow air passing through the front edge on the windward side is along the cut and raised portion 10. It deflects downward in the figure and flows toward the heat transfer tube on the leeward side. In this way, by deflecting the flow direction of the air flowing between the fins 8 of the front heat exchanger 5, the tube rows can be arranged in a staggered manner with respect to the air inflow direction. Further, in the present embodiment, the cut-and-raised portion 11 is also provided in the upper part A and the lower part B of the fins 8 of the front side heat exchanger 5 and the rear heat exchanger 6. These are provided for the purpose of improving heat transfer performance by accelerating heat transfer by disturbing the flow of incoming air. Thereby, the heat exchanger of a present Example can further improve heat transfer performance.

  Further, as shown in FIG. 1, in this embodiment, the step pitch L of the central portion C is made wider than the step pitch L ′ of the upper portion A and the lower portion C of the fins 8 of the front side heat exchanger 5. . Thereby, the flow path of the air flowing through the cut-and-raised portion 10 is expanded, and the flow rate of the inflowing air flowing therethrough is increased. As a result, the inflowing air can be sent to the leeward heat transfer tube. Thus, the heat transfer performance can be maintained by using the structure of this embodiment.

  Hereinafter, the configuration of the indoor unit of the air conditioner according to the second embodiment will be described with reference to FIGS. 6 and 7. The indoor unit of the air conditioner according to the second embodiment is characterized in that the length of the cut-and-raised portion 10 is gradually increased from the leeward side to the leeward side. The other parts are the same as those of the indoor unit according to the first embodiment, and therefore the corresponding parts are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIGS. 6 and 7, the indoor unit of the present example slides the starting point b of the cut-and-raised portion 10 in each row by a predetermined minute distance, thereby reducing the length ab of the cut-and-raised portion 10. The length is gradually increased from the windward side to the leeward side. By adopting such a shape, a large amount of air flowing in from the leading edge on the leeward side flows toward the plate part having a lower ventilation resistance than the cut-and-raised part having a higher ventilation resistance, and the dead water area on the leeward side is on the leeward side. Since it becomes difficult to be affected, it is possible to suppress a decrease in heat transfer performance.

  The indoor unit of this example has the same effect as the indoor unit according to the first embodiment, and the length of the cut-and-raised portion 10 is gradually increased from the leeward side to the leeward side. It can be made less susceptible to the effects of dead water areas and is advantageous for heat exchangers with many rows.

  The present invention can be used for an indoor unit and an outdoor unit of an air conditioner.

DESCRIPTION OF SYMBOLS 1 Housing | casing 2 Suction port 3 Cross-flow fan 4 Air outlet 5 Front side heat exchanger 6 Back side heat exchanger 7 Heat exchanger tube 8 Fin 9 Burring hole 10 Cut-and-raise part A Upper part B Central part C Lower part

Claims (7)

In a cross fin tube type heat exchanger formed by inserting a plurality of heat transfer tubes into a plurality of fins arranged in parallel in the thickness direction at a required interval,
The fin has a curved portion in at least a part in the length direction, and a plurality of rows of burring holes in the width direction and a plurality of burring holes in the length direction are opened in the curved portion. And
Each of the burring holes provided in the curved portion is arranged so that straight lines connecting the burring holes of corresponding stages in each row are substantially parallel in all stages. .   The step pitch of each burring hole established in the length direction of the fin is the step pitch in the portion where the burring holes of each step arranged in the row direction are substantially parallel to the air inflow direction. 2. The heat exchanger according to claim 1, wherein the burring holes of the respective stages arranged in the row direction with respect to the inflow direction of the pipes are larger than the step pitch in a portion that is not substantially parallel.   The heat exchanger according to any one of claims 1 and 2, wherein a cut-and-raised portion for adjusting a wind direction is formed between the burring hole forming positions of the fins.   The cut-and-raised portion for adjusting the wind direction is characterized in that the length of the cut-and-raised portion arranged on the leeward side is longer than the length of the cut-and-raised portion arranged on the leeward side. 3. The heat exchanger according to 3.   The heat exchanger according to any one of claims 1 to 4, wherein the front fin is folded back from the middle in the length direction, and the entire planar shape is formed in a substantially V shape. . A step of opening a burring hole for heat transfer tube insertion in a predetermined arrangement in a strip-shaped fin material, a step of forming a cut-and-raised portion in a predetermined arrangement around the burring hole established in the previous process, and a fin material A heat exchanger that includes a step of cutting the short side portion to adjust the length of the fin, and a step of cutting the strip-shaped fin material in the length direction to cut out the fin in which the required burring hole and cut-up portion are formed. In the manufacturing method of
In the step of opening a burring hole for heat transfer tube insertion in a predetermined arrangement in the strip-shaped fin material, formation of the burring hole opening position and the cut-and-raised portion of each stage arranged in the width direction of the fin material The position is oriented parallel to the side of the strip-shaped fin material, and the opening pitch of the burring holes and the formation pitch of the cut-and-raised portions in each row arranged in the length direction of the fin material are equal pitches. And the opening positions of the burring holes and the formation positions of the raised portions in each row arranged in the length direction of the fin material are curved in the length direction of the fin material. Manufacturing method. In an indoor unit of an air conditioner that houses an indoor heat exchanger and a once-through fan,
The indoor heat exchanger is a cross fin tube type heat exchanger formed by inserting a plurality of heat transfer tubes into a plurality of fins arranged in parallel in the thickness direction at a required interval,
The fin has a curved portion in at least a part in the length direction, and a plurality of rows of burring holes in the width direction and a plurality of burring holes in the length direction are opened in the curved portion. And
Each of the burring holes established in the curved portion is arranged so that straight lines connecting the burring holes of corresponding stages in each row are arranged substantially parallel to each other. Indoor unit.

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