JP5012972B2 - Heat exchanger bending method and heat exchanger - Google Patents

Description

  The present invention relates to a heat exchanger bending method, and in particular, a flat plate heat exchanger arranged in a state where a part of a heat transfer fin protrudes in a direction perpendicular to the longitudinal direction of a heat transfer tube is wound around a bending die. It is related with the bending method of the heat exchanger which performs a bending process by pressing in this way.

  Conventionally, there is a method of bending a heat exchanger as disclosed in Patent Document 1 (Japanese Patent Application No. 58-47318). This heat exchanger bending method involves pressing a flat heat exchanger composed of fins (heat transfer fins) and pipes (heat transfer tubes) around the curved surface of a forming ram (bending die), Bending is performed. By performing such bending, the heat exchanger can be arranged in a compact manner in an outdoor unit or the like of the air conditioner.

  However, the bending method of the heat exchanger of Patent Document 1 has a problem that a part of the heat transfer fin protruding in the direction orthogonal to the longitudinal direction of the heat transfer tube is bent. For this reason, when the bent heat exchanger is used as a heat exchanger that performs heat exchange between the refrigerant flowing in the heat transfer tube and the air flow across the heat transfer tube, the air flow resistance of the air flow is increased. There is a risk that.

  An object of the present invention is to bend a flat heat exchanger arranged in a state in which a part of the heat transfer fins protrudes in a direction perpendicular to the longitudinal direction of the heat transfer tube so as to be wound around a bending die. In the bending method of the heat exchanger which processes, it exists in suppressing that the protrusion part of a heat-transfer fin bends.

According to a first aspect of the present invention, there is provided a bending method of a flat heat exchanger arranged in a state in which a part of a heat transfer fin protrudes in a direction perpendicular to the longitudinal direction of a heat transfer tube. This is a bending method of a heat exchanger that performs bending by pressing so as to wind. In this heat exchanger bending method, a bending mold having a curved surface that changes so that the bending radius decreases from the starting point position to the end point position of the winding of the heat exchanger is adopted. . The curved surface has a first curved surface located near the start point and having a large bending radius, and a main curved surface located near the end point and having a smaller bending radius than the first curved surface. In this heat exchanger bending method, the first step is performed at the start of bending of the heat exchanger, and the main step is performed after the first step. The first step is a step of bending the heat exchanger by pressing a portion closer to the starting point of the projecting portion of the heat transfer fin so as to be wound around the first curved surface. The main step is a step of bending the heat exchanger by pressing a portion closer to the end point than a portion closer to the start point than the portion near the start point among the protruding portions of the heat transfer fins.

  In the bending method in which the heat exchanger is pressed so as to be wound around the bending die, a load is applied from the bending die to the heat transfer fin. For this reason, in the bending process which presses a heat exchanger so that it may wind around a bending die, the problem that the protrusion part of a heat-transfer fin bends arises. In particular, when a conventional bending die having a single bending radius is used, the load applied to the heat transfer fin from the bending die at the start of the bending process of the heat exchanger becomes very large. The problem that the protruding portion of the heat transfer fin bends easily.

Therefore, in this bending method, paying attention to the tendency to become large at the start of the bending process of the heat exchanger as described above, the bending die is used as the bending die from the starting point position of the bending process of the heat exchanger. The one having a curved surface that changes so that the bending radius becomes smaller toward the position is adopted. Then, at the start of the bending process of the heat exchanger, the first curved surface having a large bending radius is used to bend the portion close to the starting position among the protruding portions of the heat transfer fin , and then the main bending having a small bending radius. The surface of the projecting portion of the heat transfer fin is bent at a portion closer to the end point than a portion closer to the start point .

  For this reason, in this bending method, it is possible to reduce the load applied to the heat transfer fin from the bending die at the start of the bending process of the heat exchanger, thereby suppressing the protruding portion of the heat transfer fin from being bent. Can do.

The bending method of the heat exchanger according to the second aspect is the bending method of the heat exchanger according to the first aspect, wherein the first curved surface is formed within a winding angle range of 10 degrees from the starting position. Has been.

  In this bending method, by setting the winding angle range of the first curved surface to 10 degrees or less, it is possible to suppress an excessive increase in the size of the bent portion of the heat exchanger.

The bending method of the heat exchanger according to the third aspect is the bending method of the heat exchanger according to the first or second aspect, wherein the curved surface is between the first curved surface and the main curved surface. It further has a second curved surface that is smaller than the first curved surface and has a larger bending radius than the main curved surface. And in this heat exchanger bending method, between the first step and the main step, the portion between the portion near the starting point position and the portion near the end point position of the projecting portion of the heat transfer fin is second. A second step of bending the heat exchanger by pressing it so as to wrap around the curved surface is performed.

  When the curved surface is constituted by only the first curved surface and the main curved surface and the main step is performed immediately after the first step, the bending radius of the curved surface is reduced, and the bent portion is applied to the protruding portion of the heat transfer fin. The load may change rapidly.

  Therefore, in this bending method, a second curved surface having a bending radius smaller than that of the first curved surface and larger than that of the main curved surface is provided between the first curved surface and the main curved surface. The second step is performed between the steps.

  For this reason, in this bending method, the load applied to the protruding portion of the heat transfer fin from the bending die can be prevented from changing suddenly, thereby reliably suppressing the protruding portion of the heat transfer fin from being bent. Can do.

The bending method of the heat exchanger according to the fourth aspect is the bending method of the heat exchanger according to the third aspect, wherein the first curved surface and the second curved surface are wound angles from the starting point position to 20 degrees. It is formed within the range.

  In this bending method, by setting the wrapping angle range of the first curved surface and the second curved surface to 20 degrees or less, the size of the portion where the bending process of the heat exchanger is performed is prevented from becoming too large. be able to.

  A heat exchanger bending method according to a fifth aspect is the heat exchanger bending method according to any of the first to fourth aspects, wherein the heat exchanger includes a refrigerant and a heat transfer tube flowing in the heat transfer tube. Heat exchange with the air flow across. The protruding portion of the heat transfer fin is located downstream of the air flow of the heat exchanger.

  When a heat exchanger that has been bent is used as a heat exchanger that exchanges heat between the refrigerant and the air flow, the ventilation resistance of the air flow in the bent portion of the heat exchanger is There is a tendency to be larger than the unprocessed portion. For this reason, about the part where the bending process of a heat exchanger is performed, in order to suppress that a heat-transfer fin bends, it is preferable not to provide the protrusion part of a heat-transfer fin. However, when a heat exchanger that performs heat exchange between the refrigerant and the air flow is bent, the heat exchanger is often bent so that the upstream surface of the air flow is convex. Moreover, the protrusion part of a heat-transfer fin is often provided in the downstream of the air flow of a heat exchanger for the reason of promoting the drainage of the water adhering to a heat exchanger.

  On the other hand, in this heat exchanger bending method, even if the heat exchanger performs heat exchange between the refrigerant flowing in the heat transfer tube and the air flow crossing the heat transfer tube, the protruding portion of the heat transfer fin is bent. That can be suppressed.

  A heat exchanger bending method according to a sixth aspect is the heat exchanger bending method according to any one of the first to fifth aspects, wherein the heat transfer tube is flat and wide in the direction perpendicular to the longitudinal direction. It is a tube.

  The heat exchanger bending method according to the seventh aspect is the flat multi-hole in which the heat transfer tube is formed with a plurality of flow passage holes arranged in the width direction in the heat exchanger bending method according to the sixth aspect. It is a tube.

  In heat exchangers that use flat tubes or flat multi-hole tubes as heat transfer tubes, the load applied to the projecting portions of the heat transfer fins from the bending mold during bending is greater than heat exchangers that use circular tubes as heat transfer tubes. It tends to grow. For this reason, it is easy to produce the problem that the protrusion part of a heat-transfer fin bends.

  On the other hand, in this heat exchanger bending method, even if the heat exchanger employs a flat tube or a flat multi-hole tube as the heat transfer tube, it is possible to prevent the protruding portion of the heat transfer fin from being bent. .

  A heat exchanger bending method according to an eighth aspect is the heat exchanger bending method according to any one of the first to seventh aspects, in which heat transfer fins are brazed to the heat transfer tubes.

  In heat exchangers where the heat transfer fins are brazed to the heat transfer tubes, the heat transfer fins are affected by heat effects during brazing and thinning due to the flow of brazing material on the surface of the heat transfer fins to another location. The strength is lowered, and the projecting portion of the heat transfer fin is easily bent.

  On the other hand, in this heat exchanger bending method, even if the heat transfer fin is brazed to the heat transfer tube, the protruding portion of the heat transfer fin can be prevented from being bent.

  A heat exchanger according to a ninth aspect is a heat exchanger that is bent by the heat exchanger bending method according to any one of the first to eighth aspects.

  As described above, according to the present invention, the following effects can be obtained.

  In the heat exchanger bending method according to the first aspect and the heat exchanger according to the ninth aspect, the load applied to the heat transfer fin from the bending die can be reduced at the start of the bending process of the heat exchanger. Thereby, it can suppress that the protrusion part of a heat-transfer fin bends.

  In the heat exchanger bending method according to the second and fourth aspects, it is possible to suppress an excessive increase in the size of the portion where the heat exchanger is bent.

  In the bending method of the heat exchanger according to the third aspect, the load applied to the projecting portion of the heat transfer fin from the bending die can be prevented from changing suddenly, whereby the projecting portion of the heat transfer fin is bent. This can be reliably suppressed.

  In the bending method of the heat exchanger according to the fifth aspect, even if the heat exchanger performs heat exchange between the refrigerant flowing in the heat transfer tube and the air flow across the heat transfer tube, the protruding portion of the heat transfer fin is bent. That can be suppressed.

  In the heat exchanger bending method according to the sixth or seventh aspect, even if the heat exchanger employs a flat tube or a flat multi-hole tube as a heat transfer tube, the bent portions of the heat transfer fins are prevented from being bent. be able to.

  In the heat exchanger bending method according to the eighth aspect, even if the heat transfer fin is brazed to the heat transfer tube, the protruding portion of the heat transfer fin can be prevented from being bent.

It is a perspective view which shows the general internal structure of the outdoor unit which has the outdoor heat exchanger by which the bending method and heat exchanger of the heat exchanger concerning one Embodiment of this invention were employ | adopted. It is an expansion perspective view of the D section of FIG. It is a figure (preparation state) which shows the bending process of an outdoor heat exchanger. It is sectional drawing of a bending die. It is a figure (bending process state) which shows the bending process of an outdoor heat exchanger. It is a figure which shows the part by which the bending process of the outdoor heat exchanger was performed (a bending die is shown with a dashed-two dotted line). It is sectional drawing of the bending die in the modification 1. FIG. It is a figure which shows the part by which the bending process of the outdoor heat exchanger in the modification 1 was performed (a bending type is shown with a dashed-two dotted line). It is sectional drawing of the bending die in the modification 2. It is sectional drawing of the bending die in the modification 3.

  A bending method for a heat exchanger and a heat exchanger according to the present invention will be described with reference to the drawings.

-Schematic configuration of outdoor unit-
FIG. 1 is a perspective view showing a schematic internal structure of an outdoor unit 1 having an outdoor heat exchanger 7 in which a heat exchanger bending method and a heat exchanger according to an embodiment of the present invention are employed. The outdoor unit 1 constitutes an air conditioner that performs air conditioning by a vapor compression refrigeration cycle. The outdoor unit 1 is connected to an indoor unit (not shown) via the refrigerant communication pipes 2 and 3. In the following description, the front side in FIG. 1 is referred to as “front surface”, the back side in FIG. 1 is referred to as “rear surface”, the left side in FIG. 1 is referred to as “left side”, and the right side in FIG. 1 is the “top surface”, and the lower side of FIG. 1 is the “bottom surface”.

  The indoor unit 2 mainly includes a substantially rectangular parallelepiped box-shaped unit casing 4, a compressor 6, an outdoor heat exchanger 7, and an outdoor fan 8. In addition to the above, the indoor unit 2 accommodates various devices, valves, refrigerant pipes, etc., but the description thereof is omitted here.

  The unit casing 4 mainly includes a bottom plate 41, a top plate 42 (illustrated by a two-dot chain line), a front plate 43 (illustrated by a two-dot chain line), a side plate 44 (illustrated by a two-dot chain line), a partition plate 45, have.

  The bottom plate 41 is a horizontally long, substantially rectangular plate-like member that constitutes the bottom surface portion of the unit casing 4. The peripheral edge of the bottom plate 41 is bent upward. On the outer surface of the bottom plate 41, two fixed legs 5 fixed to the field installation surface are provided. The fixed leg 5 extends from the front side of the unit casing 4 toward the rear side.

  The top plate 42 is a horizontally long and substantially rectangular plate-like member that constitutes the top surface portion of the unit casing 4.

  The front plate 43 is a plate-like member that mainly forms the front portion of the unit casing 4 and the front portion of the right side surface. The lower part of the front plate 43 is fixed to the bottom plate 41 with screws or the like. The front plate 43 is formed with an air outlet 43a. The blower outlet 43a is an opening for blowing outdoor air taken into the unit casing 4 through suction ports (not shown) formed on the back surface and the left side surface of the unit casing 4 (arrows A to A indicating airflow). See C).

  The side plate 44 is a plate-like member that mainly constitutes the rear portion and the right back portion of the right side surface of the unit casing 4. The lower part of the side plate 44 is fixed to the bottom plate 42 with screws or the like.

  The partition plate 45 is a plate-like member disposed on the bottom plate 41. The partition plate 45 extends vertically. The partition plate 45 is disposed so as to partition the internal space of the unit casing 4 into two left and right spaces (that is, the fan chamber S1 and the machine chamber S2). The lower part of the partition plate 45 is fixed to the bottom plate 41 with screws or the like.

  Thus, the internal space of the unit casing 4 is divided into the blower chamber S1 and the machine chamber S2 by the partition plate 45. The blower chamber S <b> 1 is a space surrounded by the bottom plate 41, the top plate 42, the front plate 43, and the partition plate 45. The machine room S <b> 2 is a space surrounded by the bottom plate 41, the top plate 42, the front plate 43, the side plate 44, and the partition plate 45. In the blower room S1, an outdoor heat exchanger 7 and an outdoor fan 8 are mainly disposed. A compressor 6 is mainly disposed in the machine room S2.

  The compressor 6 is a compressor for compressing a low-pressure refrigerant in the refrigeration cycle until it becomes a high-pressure refrigerant. The compressor 6 is an approximately vertical cylindrical hermetic compressor. The compressor 6 is disposed at the approximate center in plan view in the machine room S2.

  The outdoor heat exchanger 7 functions as a refrigerant radiator that uses outdoor air as a heat source during cooling, and functions as a refrigerant evaporator that uses outdoor air as a heat source during heating. The outdoor heat exchanger 7 is a fin tube type heat exchanger constituted by a plurality of heat transfer tubes 11 and a plurality of heat transfer fins 12. The outdoor heat exchanger 7 is bent so as to form a substantially L shape in plan view. The outdoor heat exchanger 7 is disposed in the blower chamber S <b> 2 so as to follow the left side surface and the back surface of the unit casing 4 and to surround the left side surface and the back surface side of the blower fan 8. The detailed configuration and manufacturing method of the outdoor heat exchanger 7 will be described later.

  The outdoor fan 8 takes air into the blower chamber S <b> 1 through suction ports (not shown) formed on the left side surface and the back surface of the unit casing 4, passes the outdoor heat exchanger 7, and then the front surface of the unit casing 4. It is a ventilation fan which functions so that it may blow off from the blower outlet 43a formed in this. Here, the outdoor fan 8 is a propeller fan, and is disposed downstream of the outdoor heat exchanger 7 in the blower chamber S1.

-Detailed configuration of outdoor heat exchanger-
Next, the detailed structure of the outdoor heat exchanger 7 is demonstrated using FIG.1 and FIG.2. Here, FIG. 2 is an enlarged perspective view of a portion D in FIG.

  The outdoor heat exchanger 7 mainly includes a heat transfer tube 11 and heat transfer fins 21. In addition to the above, the outdoor heat exchanger 7 is provided with a header pipe and the like, but the description thereof is omitted here.

  The heat transfer tube 11 is a flat tube having a wide flat surface portion 12 in a direction orthogonal to the longitudinal direction. The heat transfer tube 11 faces the width direction of the flat surface portion 12 (in the direction of arrows A and B in FIG. 1 and in the direction of arrow E in FIG. 2) between the vertical directions with the flat surface portion 12 facing in the vertical direction. A plurality of ventilation spaces are arranged with outdoor air flow.

  The planar portion 12 is formed with a plurality of flow passage holes 13 arranged in the width direction so as to penetrate the planar portion 12 in the longitudinal direction. The refrigerant flows through each flow path hole 13. The heat transfer tube 11 is made of a metal material such as aluminum and is manufactured by extrusion molding or the like. Thus, the flat multi-hole pipe in which the several flow-path hole 13 was formed is employ | adopted as the heat exchanger tube 11 here, and the heat transfer rate by the side of a refrigerant has improved.

  The heat transfer fin 21 is a corrugated fin formed by bending a plate-shaped material having a width direction dimension larger than the width direction dimension of the flat portion 12 of the heat transfer tube 11 along the longitudinal direction of the heat transfer tube 11. . Here, when the width direction dimension of the plane part 21 is W1 and the width direction dimension of the heat transfer fin 21 is W2, the relation of the width direction dimension W1 of the plane part 12 <the width direction dimension W2 of the heat transfer fin 21 is established. Yes. The heat transfer fin 21 is made of a metal material such as aluminum. The heat transfer fin 21 has a fin body portion 22 and a fin edge portion 23.

  The fin body portion 22 is a portion disposed in the ventilation space between the upper and lower directions of the flat surface portion 12, and an upper end 24 and a lower end 25 are formed by bending a plate-like material into a waveform along the longitudinal direction of the heat transfer tube 11. ing. The upper end 24 is joined to the lower surface of the flat portion 12 by brazing. The lower end 25 is joined to the upper surface of the flat portion 12 by brazing. In addition, in order to improve heat exchange efficiency, the fin main body portion 22 is formed with a plurality of main body side cut-up portions 26 by cutting up the central portion of the fin main body portion 22 in the vertical direction. Here, the main body side cut and raised portion 26 is cut and raised in a louver shape. And the main body side cut-and-raised part 26 is formed so that the inclination direction with respect to the outdoor air flow is reversed between the upstream portion and the downstream portion of the outdoor air flow.

  The fin edge portion 23 is a portion in which a part of the heat transfer fin 21 protrudes in a direction orthogonal to the longitudinal direction of the heat transfer tube 11. More specifically, the fin edge part 23 is a part which protrudes toward the width direction outer side (here both width direction outer sides) of the heat exchanger tube 11 from each ventilation space. The fin edge portion 23 is formed with an upper end 27 and a lower end 28. The upper end 27 and the lower end 28 are provided with cuts in the vicinity of the fold lines for forming the upper end 24 and the lower end 25, thereby bending the plate material into a waveform along the longitudinal direction of the heat transfer tube 11. When the lower end 25 is formed, it is a part that is cut and raised in the vertical direction. Here, the upper end 27 and the lower end 28 are on the downstream side of the outdoor air flow in the fin edge portions 23 formed on both sides in the width direction of the heat transfer tube 11 (in FIG. 1, on the outdoor fan 8 side, in FIG. It is formed only on the fin edge 23 located on the (E side). For this reason, the fin edge portions 23 adjacent in the vertical direction are in contact with or close to each other via the upper end 27 and the lower end 28. Here, the upper end 27 and the lower end 28 are cut and raised in a substantially rectangular shape because the cut is provided in parallel to the width direction of the heat transfer tube 11, but the cut is formed in the width direction of the heat transfer tube 11. May be cut up and formed into a substantially triangular shape or a substantially trapezoidal shape. Further, in order to improve the heat exchange efficiency, the fin edge portion 23 is formed with a plurality of edge side raised portions 29a and 29b by cutting the central portion of the fin edge portion 23 in the vertical direction. The edge cut-and-raised portion 29 a located on the upstream side of the outdoor air flow is formed to have the same vertical width as that of the main body-side cut and raised portion 26. On the other hand, the edge cut-and-raised portion 29b located on the downstream side of the outdoor air flow is formed to have a shorter vertical width than the body-side cut and raised portion 26. Here, the edge cut and raised portions 29a and 29b are cut and raised in a louver shape. The edge cut-and-raised portions 29a and 29b are formed so that the inclination direction with respect to the outdoor air flow is reversed between the upstream portion and the downstream portion of the outdoor air flow. As described above, since the vertical width of the edge cut-and-raised portion 29b is shorter than that of the main body-side cut and raised portion 26, the strength of the fin edge portion 23 is prevented from being lowered.

  In the outdoor heat exchanger 7 having the above-described configuration, when functioning as a refrigerant radiator during cooling, the refrigerant that flows through the heat transfer tube 11 and the cooling source that flows through the ventilation space so as to cross the heat transfer tube 11 are used. The outdoor air exchanges heat with the heat transfer fins 21 and the heat transfer tubes 11. Then, heat dissipation of the refrigerant is performed. Further, when the outdoor heat exchanger 7 functions as a refrigerant evaporator, the refrigerant flowing in the heat transfer tube 11 and the outdoor air as a heating source flowing in the ventilation space so as to cross the heat transfer tube 11 are heat transfer fins 21. And heat exchange is performed via the heat transfer tube 11. Then, the refrigerant is evaporated. At this time, dew condensation water is generated on the surface of the heat transfer fin 21, but the fin edge 23 is formed on the downstream side of the outdoor air flow of the outdoor heat exchanger 7. Condensed water can flow downward. In particular, as described above, the fin edge portion 23 has the upper end 27 and the lower end 28, and the fin edge portions 23 adjacent to each other in the vertical direction are in contact with each other or close to each other. is doing.

-Manufacturing method of outdoor heat exchanger-
Next, the manufacturing method of the outdoor heat exchanger 7 is demonstrated using FIGS. Here, FIG. 3 is a diagram (preparation state) showing bending of the outdoor heat exchanger 7. FIG. 4 is a sectional view of the bending die. FIG. 5 is a diagram (bending state) showing bending of the outdoor heat exchanger 7. FIG. 6 is a view showing a portion where the outdoor heat exchanger 7 is bent (the bending die 55 is shown by a two-dot chain line).

  First, a flat plate-shaped outdoor heat exchanger 7 that is not bent is prepared. Here, as described above, the flat outdoor heat exchanger 7 includes a plurality of straight tubular heat transfer tubes 11 with the planar portions 12 facing each other and a ventilation space between the planar portions 12. The heat transfer fins 21 that are bent in a waveform are disposed and laminated in each ventilation space. Here, the heat transfer fins 21 are brazed to both surfaces of the flat surface portion 12. More specifically, by providing a brazing material on both surfaces of the flat surface portion 12 and heating a plurality of heat transfer tubes 11 provided with the brazing material and the heat transfer fins 21 in a brazing furnace or the like. The heat transfer tubes 11 and the heat transfer fins 21 are brazed. Thereby, as described above, the flat plate-shaped outdoor heat exchanger 7 in which the fin edge portion 23 protrudes outward in the width direction of the flat plate portion 12 is obtained. In the flat plate-shaped outdoor heat exchanger 7, as shown in FIG. 6, the upper end of the fin edge portion 23 is one of the widthwise sides of the flat portion 12 (the direction facing the downstream side of the outdoor air flow). The fin edge 23 in which 27 and the lower end 28 are formed protrudes. Further, with respect to the other side in the width direction of the flat portion 12 (the direction facing the upstream side of the outdoor air flow), the fin edge portion 23 where the upper end 27 and the lower end 28 are not formed protrudes to the upstream side of the outdoor air flow.

  Next, the flat plate-shaped outdoor heat exchanger 7 is bent using the bending apparatus 51. The bending apparatus 51 is an apparatus that performs bending by pressing the flat outdoor heat exchanger 7 so as to be wound around the bending die 55. The bending apparatus 1 described below is an example for carrying out the bending method according to the present invention. If the bending die 55 that is a feature of the bending method according to the present invention is used, Other bending apparatuses may be used.

  The bending apparatus 51 mainly includes a base plate 52, two clamps 53 and 54, and a bending die 55. The base plate 52 is a member that is stacked in a state in which at least one end in the longitudinal direction of the flat plate-shaped outdoor heat exchanger 7 protrudes. The 1st clamp 53 is a member which supports the longitudinal direction one end protruded from the base plate 52 of the outdoor heat exchanger 7 from the downward direction (refer arrow F of FIG. 3). The second clamp 54 sandwiches a portion of the outdoor heat exchanger 7 opposite to the first clamp 53 across the bending die 55 from above (see arrow G in FIG. 3) between the pace plate 52 and the second clamp 54. It is a member supported by. The bending die 55 mainly has a bending 56 and a mandrel 57. The bending 56 is a member that supports the one end in the longitudinal direction protruding from the base plate 52 of the outdoor heat exchanger 7 by sandwiching it between the first clamp 53 from above. The mandrel 57 is a member having a curved surface 58 on the outer surface that comes into contact with the outdoor heat exchanger 7. The mandrel 57 is rotationally driven in the direction of arrow H by a motor (not shown). The bending 56 is fixed to the mandrel 57. For this reason, the bending 56 moves with the rotation of the mandrel 57 and presses the outdoor heat exchanger 7 so as to be wound around the curved surface 58 of the bending die 55. Thereby, the longitudinal direction one end protruded from the base plate 52 of the outdoor heat exchanger 7 is bent. Here, in order to bend the flat outdoor heat exchanger 7 so as to have a substantially L shape, the mandrel 57 is the starting point of the bending of the outdoor heat exchanger 7 (point XS in FIGS. 4 and 6). 90 degrees to the end point (point XE in FIGS. 4 and 6). The outdoor heat exchanger 7 has a part of the heat transfer fin 21 (here, the fin edge portion 23 of the heat transfer fin 21) protrudes in a direction perpendicular to the longitudinal direction of the heat transfer tube 11. The fin edge 23 which is the protruding portion of the heat transfer fin 21 comes into contact with the curved surface 58.

  In the bending method in which the outdoor heat exchanger 7 is pressed so as to be wound around the bending die 55, a load is applied from the bending die 55 to the heat transfer fins 21. For this reason, in the bending process in which the outdoor heat exchanger 7 is pressed so as to be wound around the bending die 55, there arises a problem that the fin edge portion 23 that is the protruding portion of the heat transfer fin 21 is bent. In particular, when a bending die 55 having a single bending radius is employed as in the prior art, the bending die 55 at the start of bending of the outdoor heat exchanger 7 (near the point XS in FIGS. 4 and 6). Therefore, the load applied to the heat transfer fin 21 becomes very large, and as a result, the problem that the fin edge 23 is bent is likely to occur.

  Therefore, paying attention to the tendency to increase at the start of the bending process of the outdoor heat exchanger 7, the bending surface 58 of the bending die 55 is moved from the bending process start point XS to the end point XE of the outdoor heat exchanger 7. What changes so that a bending radius may become small is employ | adopted. Specifically, the curved surface 58 has a first curved surface 61 and a main curved surface 62. The first curved surface 61 is located closer to the start point XS (specifically, the winding angle θ1 from the start point XS to the point X1) and has a large bending radius R1. The main curved surface 62 is located near the end point XE (specifically, the winding angle θM from the point X1 to the end point XE) and has a smaller bending radius RM than the first curved surface 61. ing. Therefore, in the bending process of the outdoor heat exchanger 7, the rotation of the mandrel 57 pushes the fin edge 23, which is the protruding portion of the heat transfer fin 21, around the first curved surface 61 at the start of the bending process. The first step of bending the outdoor heat exchanger 7 is performed. Then, after this first step, the main step of bending the outdoor heat exchanger 7 is performed by pressing the fin edge 23 that is the protruding portion of the heat transfer fin 21 around the main curved surface 62. In this manner, the curved surfaces 58 (specifically, the first curved surface 61 and the main curved surface 62) of the bending die 55 are transferred to the flat plate-shaped outdoor heat exchanger 7.

  Thus, in this bending method, the load applied to the heat transfer fins 21 from the bending die 55 can be reduced at the start of the bending process of the outdoor heat exchanger 7, and the fin edge that is the protruding portion of the heat transfer fins 21. It can suppress that the part 23 bends.

  Here, since the winding angle θ1 of the first curved surface 41 is set to 10 degrees or less, it is possible to prevent the portion of the outdoor heat exchanger 7 where the bending process has been performed from becoming too large. .

  Here, as described above, the outdoor heat exchanger 7 subjected to the bending process is used as a heat exchanger that performs heat exchange between the refrigerant and the air flow. For this reason, there exists a tendency for the ventilation resistance of the outdoor air flow in the part in which the bending process of the outdoor heat exchanger 7 was performed to become large compared with the part in which the bending process is not performed. For this reason, in order to prevent the heat transfer fins 21 from being bent at portions where the outdoor heat exchanger 7 is bent, the protruding portions (here, the fin edges 23) of the heat transfer fins 21 are not provided. It is preferable to make it. However, when bending the outdoor heat exchanger 7 that performs heat exchange between the refrigerant and the outdoor air flow, as shown in FIG. 1, the surface on the upstream side of the outdoor air flow of the outdoor heat exchanger 7 is convex. In many cases, bending is performed. Moreover, the fin edge part 23 which is a protrusion part of the heat-transfer fin 21 is provided in the downstream of the outdoor air flow of the outdoor heat exchanger 23 for reasons, such as promoting drainage of the water adhering to the outdoor heat exchanger 7. There are many cases. In addition, here, in order to promote the flow of the dew condensation water generated on the surface of the heat transfer fins 21, the fin edges 23 projecting downstream of the outdoor air flow of the outdoor heat exchanger 7 are cut and raised. The upper end 27 and the lower end 28 formed by the above are provided. For this reason, the upper end 27 and the lower end 28 of the fin edge 23 are in contact with the curved surface 58 of the mandrel 57. Since these upper end 27 and lower end 28 are parts formed by cutting and raising, the strength is very weak.

  In contrast, in this bending method, as described above, the load applied to the heat transfer fins 21 from the bending die 55 at the start of bending of the outdoor heat exchanger 7 can be reduced. For this reason, although it is a heat exchanger which performs heat exchange between the refrigerant flowing in the heat transfer tube 11 and the outdoor air flow crossing the heat transfer tube 11, the fin edge 23 which is the protruding portion of the heat transfer fin 21 is bent. That can be suppressed.

  Here, as described above, the heat transfer tube 11 is a flat tube that is wide in the direction orthogonal to the longitudinal direction. Moreover, the flat tube employed in the heat transfer tube 11 is a flat multi-hole tube in which a plurality of flow path holes 13 arranged in the width direction are formed. For this reason, compared with the case where a circular pipe is adopted as a heat transfer tube, the load applied to the protruding portion of the heat transfer fin from the bending die tends to increase during bending. For this reason, it is easy to produce the problem that the protrusion part (here fin edge part 23) of a heat-transfer fin bends.

  In contrast, in this bending method, as described above, the load applied to the heat transfer fins 21 from the bending die 55 at the start of bending of the outdoor heat exchanger 7 can be reduced. For this reason, although it is a heat exchanger which employ | adopted the flat tube or the flat multi-hole tube as the heat exchanger tube 11, it can suppress that the fin edge part 23 bends.

  Further, here, the heat transfer fins 21 are brazed to the heat transfer tubes 11 as described above. For this reason, the strength of the heat transfer fins 21 is reduced due to the heat effect during brazing and the thinning due to the flow of brazing material on the surface of the heat transfer fins to another place, and the protruding portions of the heat transfer fins 21 Here, the fin edge portion 23 is easily bent.

  In contrast, in this bending method, as described above, the load applied to the heat transfer fins 21 from the bending die 55 at the start of bending of the outdoor heat exchanger 7 can be reduced. For this reason, although the heat transfer fin 21 is a heat exchanger brazed to the heat transfer tube 11, the fin edge portion 23 can be prevented from being bent.

-Modification 1 of manufacturing method of outdoor heat exchanger
In the bending method of the outdoor heat exchanger 7 described above, the bending surface 55 of the bending die 55 having only the first curved surface 61 and the main curved surface 62 is adopted, and the main step is performed immediately after the first step. I am doing so. However, in such a bending method, the load applied from the bending die 55 to the projecting portion (here, the fin edge portion 23) of the heat transfer fin 21 is rapidly changed by decreasing the bending radius of the curved surface 58. There is a fear.

  Therefore, in the bending method of the present modification, as shown in FIGS. 7 and 8, as the curved surface 58 of the bending die 55, the first curved surface 61 is interposed between the first curved surface 61 and the main curved surface 62. And a second curved surface 63 having a smaller bending radius R2 than the main curved surface 62 is provided. Specifically, the first curved surface 61 is located closer to the start point XS (specifically, the winding angle θ1 from the start point XS to the point X1) and has a large bending radius R1. Yes. The second curved surface 63 is located in the range of the winding angle θ2 from the point X1 that is the end point of the first curved surface 61 to the point X2, is smaller than the first curved surface 61, and is smaller than the main curved surface 62. Has a large bending radius R2. The main curved surface 42 is located near the end point XE (specifically, the winding angle θM from the point X2 to the end point XE) and has a smaller bending radius RM than the second curved surface 63. ing. Then, between the first step and the main step, the protruding portion of the heat transfer fin 21 (here, the fin edge portion 23) is pressed so as to be wound around the second curved surface 63, and the outdoor heat exchanger 7 is bent. The second step of processing is performed. Here, FIG. 7 is a cross-sectional view of the bending die 55 in this modification. FIG. 8 is a view showing a portion where the outdoor heat exchanger 7 is bent in the present modification (the bending die 55 is shown by a two-dot chain line).

  Thereby, in the bending method of this modification, the load applied from the bending die 55 to the protruding portion of the heat transfer fin 21 (here, the fin edge portion 23) can be prevented from changing suddenly. It is possible to reliably suppress the bending of 23.

  In addition, since the winding angle of the first curved surface 61 and the second curved surface 63 (that is, θ1 + θ2) is set to 20 degrees or less, the size of the portion where the bending of the outdoor heat exchanger 7 is performed. Can be prevented from becoming too large.

-Modification 2 of manufacturing method of outdoor heat exchanger
In the bending method of the outdoor heat exchanger 7 of Modification 1 described above, the bending surface 55 of the bending die 55 is the one having the first curved surface 61, the second curved surface 63, and the main curved surface 62. The main step is performed after the first step and the second step. However, in order to further reduce the change in the load applied from the bending die 55 to the protruding portion of the heat transfer fin 21 (here, the fin edge portion 23), the bending radius is changed so as to be further reduced in multiple steps. May be.

  In this case, the bending radius of the curved surface 58 of the bending die 55 may be reduced in multiple steps so as to satisfy FIG. 9 and the following general formula.

That is, the line segment OnXn = bending radius Rn (where On is the center of the bending radius Rn), and the mandrel 57 rotates by θn degrees in the state of the bending radius Rn (here, the entire rotation is 90 degrees). Suppose) goes forward,
Σθ = θ1 + θ2 +... + Θn−1 = 90 degrees.

Here, since the bending radius Rn is not more than the length of the line segment On-1Xn,
R1 ≧ R2 ≧ ・ ・ ・ ≧ Rn
It becomes.

  The curved surface 58 having the first curved surface 61 and the main curved surface 62 described above, or the curved surface 58 having the first curved surface 61, the second curved surface 63, and the main curved surface 62 of Modification 1 is also subscripted. If “S”, “M” and “E” are replaced with “1”, “n” and “n” and n = 2 or n = 3, it is understood that the above general formula is applicable. Further, when n is increased infinitely, the curved surface 58 (that is, a line connecting the start point XS and the end point XE) forms a substantially involute curved surface.

  As a result, in the bending method of the present modification, the bending is substantially performed in multiple stages between the first step of bending with the first curved surface and the main step of bending with the main curved surface. The second step of bending with the second curved surface having a small radius is performed. And the change of the load concerning the protrusion part (here fin edge part 23) of the heat-transfer fin 21 from the bending die 55 can be made still smaller than the bending method of said modification 1. FIG.

-Modification of manufacturing method of outdoor heat exchanger 3-
In the bending method of the outdoor heat exchanger 7 described above, a bending die 55 in which the curved surface 58 is smoothly connected from the start point to the end point of the bending process is employed. For example, the bending die 55 in Modification 1 employs a smoothly connected first curved surface 61, second curved surface 63, and main curved surface 62. However, the first curved surface 61, the second curved surface 63, and the main curved surface 62 do not necessarily need to be smoothly connected, and the first curved surface 61, the second curved surface 63, and the main curved surface 62 are somewhat connected. You may connect through a level | step difference.

  For example, as shown in FIG. 10, a step 64 may exist between the second curved surface 63 and the main curved surface 62 in the bending die 55 of the first modification. Here, as the mandrel 57, one having only the main curved surface 62 is adopted, and as the bending 56, one provided with an attachment 65 having a first curved surface 61 and a second curved surface 63 formed on the surface thereof is provided. Adopted. For this reason, the thickness of the end of the attachment 65 on the mandrel 57 side appears as a step 64. That is, the step 64 is formed such that the end of the second curved surface 63 on the main curved surface 62 side protrudes to the outer peripheral side from the end of the main curved surface 62 on the second curved surface 63 side. The step 64 is as small as several mm.

  Also in this modification, the same effect as the processing method of the outdoor heat exchanger 7 can be obtained.

  For example, in the configuration of the bending die 55 having the step 64 as in this modification, the bending radii R1, RM, and R2 of the first curved surface 61, the second curved surface 63, and the main curved surface 62 are set to 200 mm, 77 mm, and 70 mm, respectively. And The winding angle θ1 of the first curved surface 61 is 5 degrees, the winding angle θ2 of the second curved surface 63 is 13 degrees, and the winding angle θM of the main curved surface 62 is 72 degrees. When the bending of the outdoor heat exchanger 7 is performed using such a bending die 55, the load applied to the heat transfer fins 21 from the bending die 55 can be reduced when the bending of the outdoor heat exchanger 7 is started. This can prevent the protruding portions of the heat transfer fins 21 from being bent.

-Other embodiments-
As mentioned above, although embodiment of this invention and its modification were demonstrated based on drawing, specific structure is not restricted to said embodiment and its modification, It changes in the range which does not deviate from the summary of invention. Is possible.

(A)
In the above-described embodiment and its modification, the present invention is applied to the outdoor heat exchanger 7 that uses a flat multi-hole tube as the heat transfer tube 11 and uses a corrugated fin as the heat transfer fin 21. However, the present invention is not limited to this.

  For example, the present invention may be applied to a heat exchanger that uses a flat tube as a heat transfer tube. Moreover, you may apply this invention with respect to the heat exchanger which uses a circular tube as a heat exchanger tube. Moreover, you may apply this invention with respect to the heat exchanger which uses the plate fin provided as a heat transfer fin at predetermined intervals in the longitudinal direction of a heat exchanger tube.

  However, in a heat exchanger that uses a circular tube as the heat transfer tube and uses a plate fin as the heat transfer fin, the heat transfer tube and the heat transfer fin are obtained by expanding the tube after inserting the heat transfer tube into the heat transfer fin. Is fixed. For this reason, since the heat influence and the thickness reduction like the case where the heat transfer tube and the heat transfer fin are fixed by brazing do not occur, the strength of the portion protruding in the direction perpendicular to the longitudinal direction of the heat transfer tube of the heat transfer fin The decline of the is suppressed. In addition, since the heat transfer tube is a circular tube, the load received from the bending die is smaller than when a flat tube is used.

  For this reason, the bending method of the present invention uses a flat tube (flat multi-hole tube) as a heat transfer tube as in the above-described embodiment and its modifications, and also fixes the heat transfer tube and the heat transfer fin. It is very effective for heat exchangers using brazing.

(B)
In the above-described embodiment and its modification, the present invention is applied when the outdoor heat exchanger 7 is bent so as to be substantially L-shaped, but the present invention is not limited to this.

  For example, the present invention may be applied when bending the outdoor heat exchanger 7 so as to form a substantially U shape.

(C)
In the above embodiment and its modifications, the present invention is applied to the outdoor heat exchanger 7 constituting the outdoor unit, but the present invention is not limited to this.

  For example, the present invention may be applied to an indoor heat exchanger constituting an indoor unit, a heat exchanger in another type of air conditioner, and the like.

  The present invention performs bending work by pressing a flat heat exchanger arranged in a state in which a part of the heat transfer fins protrudes in a direction perpendicular to the longitudinal direction of the heat transfer tube so as to be wound around a bending die. It can be widely applied to the bending method of the heat exchanger to be performed.

7 Outdoor Heat Exchanger 11 Heat Transfer Tube 21 Heat Transfer Fin 55 Bending Mold 58 Curved Surface 61 First Curved Surface 62 Main Curved Surface 63 Second Curved Surface

Japanese Utility Model Publication No. 58-47318

Claims (9)

A flat plate-shaped heat exchanger (7) arranged in a state where a part of the heat transfer fin (21) protrudes in a direction perpendicular to the longitudinal direction of the heat transfer tube (11) is wound around the bending die (55). In the bending method of the heat exchanger that performs bending by pressing,
The bending mold employs a bending surface (58) that changes so that the bending radius decreases from the starting point position to the ending point position of the bending process of the heat exchanger ,
The curved surface includes a first curved surface (61) positioned near the start point and having a large bending radius, and a main curved surface positioned near the end point and having a smaller bending radius than the first curved surface. (62)
At the start of the bending process of the heat exchanger, a first part of the heat transfer fin is pressed by pressing a portion closer to the starting point of the protruding portion of the heat transfer fin around the first curved surface. Do the steps,
After the first step, the heat exchanger is bent by pressing a portion of the projecting portion of the heat transfer fin that is closer to the end point position than the portion near the start position so as to be wound around the main curved surface. Do the main steps,
Bending method of heat exchanger. The first curved surface (61) is formed within a winding angle range of 10 degrees from the starting position .
The method for bending a heat exchanger according to claim 1. The curved surface (58) has a bending radius smaller than the first curved surface and larger than the main curved surface between the first curved surface (61) and the main curved surface (62). Two curved surfaces (63),
Between the first step and the main step, a portion between the portion near the start point position and the portion near the end point position of the protruding portion of the heat transfer fin (21) is the second curved surface. A second step of bending the heat exchanger (7) by pressing it so as to wind it,
The method for bending a heat exchanger according to claim 1 or 2. The first curved surface (61) and the second curved surface (63) are formed within a winding angle range of 20 degrees from the starting position .
The method for bending a heat exchanger according to claim 3. The heat exchanger (7) performs heat exchange between the refrigerant flowing in the heat transfer tube (11) and the air flow across the heat transfer tube,
The protruding portion of the heat transfer fin (21) is located downstream of the air flow of the heat exchanger,
The bending method of the heat exchanger of any one of Claims 1-4. The heat transfer tube (11) is a flat tube that is wide in a direction perpendicular to the longitudinal direction.
The bending method of the heat exchanger of any one of Claims 1-5. The heat transfer tube (11) is a flat multi-hole tube in which a plurality of flow path holes arranged in the width direction are formed.
The method for bending a heat exchanger according to claim 6. The heat transfer fin (21) is brazed to the heat transfer tube (11),
The bending method of the heat exchanger of any one of Claims 1-7.   A heat exchanger (7) bent by the method for bending a heat exchanger according to any one of claims 1 to 8.

Images