JP3580942B2 - Flat tubes for heat exchangers and heat exchangers equipped with the tubes - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a flat tube for flowing a heat exchange medium in, for example, a condenser or an evaporator for a car air conditioner, an outdoor heat exchanger for a room air conditioner, an oil cooler for an automobile, an industrial oil cooler, and various other heat exchangers.,Heat exchanger using tube,Car air conditioning system and room air conditioner using this heat exchanger, and method of manufacturing perforated flat tubeAbout.
[0002]
[Prior art and its problems]
Conventionally, as a heat exchanger of this type, a plurality of flat tubes arranged in the thickness direction at predetermined intervals with fins interposed therebetween, and arranged in a communication connection state at both ends thereof A type having a pair of hollow headers is known.
[0003]
In recent years, this type of heat exchanger has rapidly become widespread as a small and lightweight heat exchanger capable of exhibiting high performance, for example, as a condenser (condenser) for a car air conditioner. In this type of heat exchanger, further weight reduction and higher performance are desired, and various improvement measures are being implemented.
[0004]
For example, as a measure for improving the air-side performance, it is possible to increase the air-side heat transfer area and reduce the air-side pressure loss by further reducing the thickness of the flat tube. On the other hand, as a heat exchange medium side performance improvement measure, in addition to the above, by equipping the inner tube with a flat tube, the heat transfer area on the heat exchange medium side is increased to improve the heat transfer coefficient, and the flat tube is improved. To improve the heat transfer coefficient by reducing the fluid diameter of the heat exchange medium passage in the inside.
[0005]
However, regarding the reduction of the thickness of the flat tube, in the case of an extruded flat porous tube manufactured by extruding a billet of aluminum or the like, the thinner the tube thickness, the more difficult the extrusion process. Therefore, there is a problem that productivity is reduced.
[0006]
In order to solve such a problem, a flat plate manufactured by bending a single strip-shaped tube element as shown in, for example, Japanese Utility Model Publication No. 46-6951 is used instead of the flat tube made by extrusion. Tubes are known. This tube is formed by bending a strip-shaped tube element so as to be folded at an intermediate portion in the width direction, and in a state where inner fins are interposed between the tube elements, the opposite edge portions of the tube element are pushed together. It is manufactured by wrapping and joining.
[0007]
In this flat tube, the plate thickness can be reduced, and the inner tube is equipped to improve the heat transfer coefficient and reduce the fluid diameter. It is possible to plan. However, on the other hand, it has the following problems.
[0008]
That is, as described above, this type of flat tube needs to be inserted into the tube insertion hole formed in the hollow header and connected to the header in a liquid-tight manner. However, the above-mentioned flat tube has the above-mentioned winding joining edge portion in a laterally protruding state at the width direction side edge portion. Therefore, in order to connect the tube insertion end and the header in a liquid-tight state, the tube insertion hole of the header must be set to a complicated shape corresponding to the cross-sectional shape of the tube, and the tube insertion hole is formed. However, this is not only troublesome and causes a reduction in manufacturing efficiency, but also causes a decrease in the adhesion of the connecting portion between the tube and the header.
[0009]
The present invention has been made in view of the above-described problems, and has excellent performance on both the air side and the heat exchange medium side, and is easy to manufacture and has high reliability and high performance and light weight. It is an object of the present invention to provide a flat tube for an exchanger.
[0010]
Further, the present invention provides a heat exchanger which is excellent in performance on both the air side and the heat exchange medium side, and which can achieve high performance and light weight and which is easy to manufacture and highly reliable., A car air conditioning system and a room air conditioner using the heat exchanger, and a method of manufacturing a porous flat tubeThe purpose is also to provide.
[0011]
[Means for Solving the Problems]
In order to achieve the above object, a heat exchanger tube according to the present invention comprises a pair of strip-shaped tube elements arranged in opposition and an inner fin interposed between these two tube elements. The corresponding width-direction side edges of the tube element are wound around the widthwise intermediate portion of the tube element and connected and integrated, and have winding-joining edges on both widthwise side edges. A flat tube, characterized in that both surfaces in the thickness direction of the tube are formed flush or substantially flush over the entire region in the tube width direction including the winding joining edge. Is what you do.
[0012]
SaidA concave groove for drainage may be formed at the center in the width direction of the flat tube.
[0013]
In addition, while the central portion in the width direction of one of the tube elements is bent in a concave shape, the corresponding portion of the corrugated inner fin is formed flat correspondingly, and at that position, the one of the tube element and the inner fin are formed. And the other tube element may be integrated by brazing in close contact.
[0014]
Further, as inner fins, a partitioning and reinforcing wall extending in the height direction to partition the inside of the tube in the width direction to form a heat exchange medium flow passage extends straight along the length direction of the tube over the entire length of the tube. It is good also as composition.
[0015]
In addition, as the inner fin, the partition and reinforcing wall extending in the height direction that partitions the inside of the tube in the width direction to form the heat exchange medium flow path is shifted in the width direction by a predetermined length along the tube length direction. It is good also as a structure which is arranged.
[0016]
Further, the heat exchanger according to the present invention has a plurality of flat tubes arranged in parallel at predetermined intervals in the thickness direction with outer fins interposed therebetween, and at both ends of these flat tubes. In a heat exchanger including a pair of hollow headers arranged in a communication connection state, the flat tubes are arranged so as to face each other with a pair of tube elements having an inner fin interposed therebetween. The corresponding width-direction side edges of the tube element are wound and joined together, and have a winding-joining edge on both width-direction edges, and both sides of the tube in the thickness direction are formed by the winding. It is characterized in that it is formed flush or substantially flush over the entire area in the tube width direction including the joining edge.
[0017]
In this heat exchanger, tube insertion holes are drilled at intervals along the length direction of each header, and the ends of the flat tubes are inserted and arranged in the insertion holes, and joined and connected in a liquid-tight state by brazing. It may be.
[0018]
Further, the outer fins may be arranged in an overhang state in which the width is set to be wider than the width of the flat tube, and one end of the fins coincides with one side edge of the flat tube. In this case, the outer fin may have another end protruding toward the windward side.
[0019]
The outer fin may have a louver formed only at the center.
[0020]
The heat exchanger may be used as a car air conditioning system or a room air conditioner.
[0021]
Further, the method for manufacturing a porous flat tube includes an upper tube element having a bent edge bent downward on both side edges in the width direction and an outward tip edge bent outward from the tip thereof, An inner fin is interposed between the upper tube element and the lower tube element by using a lower tube element having a bent edge portion bent upward at an edge and an inner fin bent in a corrugated shape. In this state, the two tube elements are arranged in a superposed state, the left and right bent edges of the lower tube element are folded over the outward end edge of the upper tube element, and the folded portion is the upper tube element. It is characterized by being folded up along the bent edge of the multi-partition / reinforcement wall that partitions the inside in the width direction and joined to both side edges in the width direction And that a part.
[0022]
In this method of manufacturing a porous flat tube, the interval between the bent edges of the lower tube element is set to be substantially the same as the interval between the outwardly directed distal edges of the upper tube element, so that the upper tube element fits smoothly. The size may be set so as to be fitted.
[0023]
In the folded state, an interval (t1) is formed between the tip of the bent edge of the lower tube element and the bent edge of the upper tube element, and the interval (t1) is determined by the bending of the lower tube element. The interval may be set so as to correspond to the thickness of the edge.
[0024]
The inner fin has a height (Hf) set to correspond to the height of the bent edge of the upper tube element, and a width (Wf) set to be slightly smaller than the distance between the two bent edges of the element. It may be.
[0025]
Further, as the inner fin, a partitioning / reinforcing wall extending in the height direction to partition the inside of the tube in the width direction to form the heat exchange medium flow passage extends straight along the length direction of the tube over the entire length of the tube. Things may be used.
[0026]
Further, as inner fins, a partitioning / reinforcing wall extending in the height direction that partitions the inside of the tube in the width direction to form the heat exchange medium flow passage is shifted in the width direction by a predetermined length along the length direction of the tube. May be used.
[0027]
Further, in another method of manufacturing a porous flat tube, the cross-sectional shape is set to be the same, and a bent edge is provided on both side edges, and an outward edge is extended from one of the bent edges. The upper tube element and the lower tube element are used, and the two tube elements are overlapped with each other with the inner fin interposed between them. , Placed inside the bent edge of the other tube element, bent so that the bent edge of one tube element overlaps the outward edge of the other tube element, and similarly for the other tube element It is characterized in that it is folded in such a way that the folded part is wrapped around the inside and partitions the inside in the width direction And that a MakiYadoriki engagement edge on the partition and the reinforcing wall and the widthwise side edges of a few.
[0028]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, the present invention will be described based on illustrated embodiments.
[0029]
1 to 4 show a first embodiment of the present invention. FIG. 1 shows a front view of a heat exchanger (H) suitably used as a condenser in a car air conditioning system. The heat exchanger (H) includes a number of perforated flat tubes (10), An outer fin (14) interposed between the tubes (10), and a pair of left and right headers (15) and (16) arranged in a communication connection state at both ends of the tube (10). .
[0030]
The flat tube (10) is, as shown in FIGS. 2 and 4, a porous flat tube provided with a plurality of partitioning and reinforcing walls (13a) for partitioning the inside in the width direction. This tube (10) is composed of a pair of upper and lower aluminum thin strip-shaped tube elements (11) and (12) and an inner fin (13) also made of aluminum and interposed between the two tube elements. Have been. Then, the corresponding widthwise side edges of both the tube elements (11) and (12) are wound around the center in the width direction of the tube elements (11) and (12), and connected and integrated, It has a winding joining edge (10a) (10a) on both side edges in the width direction.
[0031]
In the flat tube (10), the height (H1) of the winding joining edges (10a) (10a) is set to be the same or substantially the same as the thickness of the tube middle part. Accordingly, the outer surface is formed such that both surfaces in the thickness direction of the tube (10) are flush or substantially flush over the entire region in the tube width direction including the winding joining edges (10a) (10a). The fin (14) is formed by shaping a sheet material having a width substantially equal to the width of the flat tube (10) into a corrugated shape to cut and raise a louver (14a). The sheet material is made of a thin aluminum plate for the purpose of easily performing the brazing integration with the flat tube (10) and the brazing integration with the side plate (17) described later. An aluminum brazing sheet in which a brazing material layer is clad on both front and back surfaces of a core material is preferably used.
[0032]
The headers (15) and (16) are formed by bending a single aluminum brazing sheet in which a brazing material layer is clad on an inner surface or an outer surface, preferably both surfaces, of an aluminum core material into a substantially circular cross section and have both side edges thereof. The dowels are brought into a butted state and brazed and integrated by the brazing material layer. As described above, a clad tube in which a brazing material layer is formed on the inner surface, outer surface, or both inner and outer surfaces of an aluminum tube is used as a header constituent member. The cladding tube may be manufactured by electric resistance welding, or may be manufactured by extrusion or other methods. Further, as the brazing material layer, generally, an Al—Si alloy having a Si content of about 6 to 13 wt% is used.
[0033]
Tube insertion holes (15a) (16a) are formed in the headers (15) (16) at intervals along the length direction thereof, and the flat holes are inserted into the insertion holes (15a) (16a). The corresponding end of the tube (10) is inserted and arranged firmly and in a liquid-tight manner by brazing. In the present invention, the flat tube (10) is flush or substantially flush over the entire area in the width direction as described above, and the winding joining edge portions (10a) (10a) have a tube width. It is formed so as to be integrally wound around the center side and not to project sideways. Therefore, the tube insertion holes (15a) and (16a) need only be formed to have the same simple slit shape as in the related art without having a special shape, and the formation operation can be easily performed. At the same time, brazing between the headers (15) and (16) and each flat tube (10) can be ensured.
[0034]
Such brazing is performed by inserting the ends of the flat tubes (10) into the tube insertion holes (15a) (16a) and temporarily brazing them by vacuum brazing or the like. Joined. After such brazing, sufficient fillets are formed at the joints between the headers (15) and (16) and the flat tube (10), and the headers (15) and (16) and the flat tube (10) are firmly tightly closed. It becomes what was joined and integrated.
[0035]
When brazing and fixing the headers (15) and (16) to the flat tube (10), a brazing sheet coated with brazing is used as a material for the outer fin (14), or as a material for the flat tube (10). If a clad tube having an outer surface coated with a brazing material layer is used, the flat tube (10) and the outer fin (14) are simultaneously brazed between the headers (15) and (16) and the flat tube (10). Can be performed, and the productivity of the heat exchanger (H) can be further improved.
[0036]
Further, closing lids (18), (18), (18), (18) are attached to the upper and lower ends of each header (15), (16) by brazing. Such brazing is performed by the brazing material layer coated on the headers (15) and (16) or the brazing material layer further coated on the lid (18). Further, a refrigerant inlet pipe (19) is connected to the upper outer surface of the left header (15) in a laterally projecting manner by brazing, while the refrigerant inlet pipe (19) is laterally projecting in a lower side of the right header (16). The outlet pipe (20) is connected by brazing. This brazing is usually performed with a brazing material layer coated on the headers (15) and (16).
[0037]
In addition, the code | symbol (17) shown in FIG. 1 is the upper and lower side plates arrange | positioned outside the outermost outer fin (14).
[0038]
One partition plate (21) is provided in each of the headers (15) and (16), whereby each of the headers (15) and (16) is divided into two upper and lower chambers. The left partition plate (21) is provided at a position substantially at the center of the left header (15), and the right partition plate (21) is provided at a position closer to the lower side of the right header (16).
[0039]
With the installation of the partition plate (21) as described above, all the refrigerant passages constituted by the tube groups are changed to the inlet-side passage group (A), the outlet-side passage group (C), and the intermediate passage located between them. It is divided into three passage groups of group (B). Therefore, the refrigerant flowing from the refrigerant inlet pipe (19) is sequentially circulated around each of the passage groups (A), (B), and (C) in a meandering manner. The inlet-side passage group (A) includes a larger number of tubes, that is, the number of refrigerant passages, than the intermediate passage group (B), and has a passage sectional area larger than that of the intermediate passage group (B). Have been. The intermediate passage group (B) includes a larger number of tubes, that is, the number of refrigerant passages, than the outlet-side passage group (C), and has a passage cross-sectional area larger than that of the outlet-side passage group (C). Is set.
[0040]
In the above configuration, the refrigerant flowing from the upper refrigerant inlet pipe (19) of the left header (15) passes through each flat tube (10) of the inlet side passage group (A) and reaches the right header (16). The refrigerant outlet pipes are reversed to flow through the respective passages of the intermediate passage group (B) to the left header (15), and further reversed to flow through the respective passages of the outlet side passage group (C) to the right header (16). It flows out of the condenser from (20). While flowing through each of the passage groups (A), (B), and (C), heat exchange is performed with the air flowing through the air flow gap including the outer fin (14) formed between the flat tubes (10).
[0041]
Although the refrigerant passing through the inlet-side passage group (A) is still in a gasified state with a large volume, the heat transfer area is reduced because the passage cross-sectional area of the inlet-side passage group (A) is set large. The refrigerant is large, and the refrigerant is efficiently condensed. The refrigerant passing through the intermediate passage group (B) is partially liquefied in the inlet-side passage group (A), so that it has a gas-liquid mixed state. Accordingly, although the heat transfer area may be small, the passage cross-sectional area of the intermediate passage group (B) is set smaller than that of the inlet-side passage group (A). The refrigerant can be passed while being performed. When the refrigerant passes through the outlet side passage group (C), the refrigerant is already in a liquid state and has a small volume, so that the cross sectional area of the passage may be small. Since it is set smaller than the intermediate passage group (B), the inlet side passage group (A) corresponding to the condensing portion and the outlet side passage corresponding to the supercooling portion from the intermediate passage group (B). By reducing the passage cross-sectional area of each passage group toward the group (C), efficient heat exchange is performed.
[0042]
Incidentally, the flat perforated tube (10) is manufactured as follows.
[0043]
First, as shown in FIG. 3A, a bent edge (11a) bent downward on both side edges in the width direction and an outward tip edge bent outward from the tip as the upper tube element (11). A part having a portion (11b) is prepared.
[0044]
On the other hand, a lower tube element (12) having bent edges (12a) (12a) bent upward on both side edges in the width direction is prepared as shown in FIG. The interval between the bent edges (12a) and (12a) is set to be substantially the same as the interval between the outwardly directed distal edges (11b) and (11b) of the upper tube element (11). 11) is set to a size such that it fits snugly.
[0045]
Also, a corrugated one is prepared as the inner fin (13). As the inner fin (13), the height (Hf) is set so as to correspond to the height of the bent edge (11a) of the upper tube element (11), and the width (Wf) is the same as the element (11). The two bent edge portions (11a) and (11a) are prepared so as to be slightly narrower than each other. In this embodiment, as the inner fin (13), a partition / reinforcement wall (13a) extending in the height direction forming a heat exchange medium flow passage by partitioning the inside of the tube (10) in the width direction is used. The partition and reinforcing wall (13a) extend straight along the length of the tube (10) over the entire length of the tube (10). So-called offset fins arranged so as to be shifted in the width direction, or fins of other known various shapes may be employed.
[0046]
Next, as shown in FIG. 3 (b), both tube elements (11) are disposed with the inner fin (13) interposed between the upper tube element (11) and the lower tube element (12). ) (12) is arranged in a superposed state.
[0047]
Thereafter, as shown in FIG. 3 (c), the left and right bent edges (12a) (12a) of the lower tube element (12) are connected to the outward tip edges (11b) (11b) of the upper tube element (11). ) Fold it up. In this folded state, a gap (t1) is formed between the tip of the bent edge (12b) of the lower tube element (12) and the bent edge (11a) of the upper tube element (11). . This interval (t1) is set to be an interval corresponding to the thickness of the bent edge (12a) of the lower tube element (12). Then, as shown by the arrow in the figure, the folded portion is folded up along the bent edge (11a) of the upper tube element (11).
[0048]
Thereby, as shown in FIG. 4, a perforated flat tube provided with a plurality of partitioning / reinforcing walls (13a) for partitioning the inside in the width direction and winding joining edges (10a) (10a) on both side edges in the width direction. (10) is obtained.
[0049]
In the flat tube (10), the height (H1) of the winding joining edges (10a) (10a) is set to be the same or substantially the same as the thickness of the tube middle part. Therefore, both surfaces in the thickness direction of the tube (10) are formed flush or substantially flush over the entire region in the tube width direction including the winding joining edges (10a) (10a). 5 and 6 show a modification of the flat tube.
[0050]
The flat tube (30) according to this embodiment also includes an upper tube element (31), a lower tube element (32), and an inner fin (33) as shown in FIG. The upper tube element (31) and the lower tube element (32) have the same cross-sectional shape, and both have bent edges (31a) (32a) on both side edges. The outward edge portions (31b) and (32b) extend from one of the bent edge portions (31a) and (32a).
[0051]
The flat tube (30) is manufactured through the steps shown in FIGS.
[0052]
That is, as shown in FIG. 5 (b), the two tube elements (31) and (32) are overlapped with each other with an inner fin (33) similar to that of the above-described embodiment interposed therebetween. At this time, as shown in the drawing, the two tube elements (31) and (32) are connected to the outward edge (31b) or (31a) of one tube element (31) or (32). It is arranged so as to be located inside the bent edge portion (32a) or (31a) of (32) or (31).
[0053]
Next, the bent edge portion (31a) of one tube element (31) is folded so as to overlap the outward edge portion (32b) of the other tube element (32). The other tube element (32) is similarly bent. In this bent state, the distance (t1) between the tip of the bent edge portion (31a) of the one tube element (31) and the bent edge portion (32a) of the other tube element (32) opposing in close proximity thereto. However, it is the same as in the previous embodiment that the thickness is set so as to correspond to the thickness of the bent edge portion (31a).
[0054]
Then, as shown by the arrow in the figure, the folded portion is folded so as to be wound inside.
[0055]
Thereby, as shown in FIG. 6, a perforated flat tube provided with a plurality of partitioning / reinforcing walls (33a) for partitioning the inside in the width direction and winding joining edges (30a) (30a) on both side edges in the width direction. (30) is obtained.
[0056]
Also in this flat tube (30), the height (H1) of the winding joining edge portions (30a) (30a) is set to be the same or substantially the same as the thickness of the tube middle portion, similarly to the above-described embodiment. . Therefore, both surfaces in the thickness direction of the tube (30) are formed flush or substantially flush over the entire region in the tube width direction including the winding joining edges (30a) (30a).
[0057]
7 to 10 show a heat exchanger according to another embodiment.
[0058]
The heat exchanger of this embodiment has the same basic structure as the heat exchanger according to the above-described embodiment, and the corresponding portions are denoted by the same reference numerals and detailed description thereof will be omitted.
[0059]
This heat exchanger is different in that the headers (15) and (16) are arranged in a vertical state in a vertical position, and the flat tubes (40) are arranged in a vertical state in a horizontal direction. Another difference is that the inside of the headers (15) and (16) is not divided by the partition plate. Therefore, in this heat exchanger, the refrigerant flowing into the upper header (15) from the refrigerant inlet pipe (19) joins the lower header (16) via the plurality of flat tubes (40), and the refrigerant outlet. It is discharged outside through the pipe (20).
[0060]
In this heat exchanger, since the flat tubes (40) are arranged along the vertical direction, when the heat exchanger is used as a condenser, the dew condensation water on the tube surface flows down smoothly, It has excellent drainage performance.
[0061]
In this embodiment, for the purpose of further improving drainage performance, as each of the flat tubes (40), as shown in FIG. 8 and FIG. 40a) is used. This tube (40) has the same basic structure as the tube (10) shown in FIG.OneA central portion in the width direction of the tube element (11) is bent in a concave shape, and a corresponding portion of the corrugated inner fin (13) is formed flat correspondingly. And in that position,OneTube element (11), inner fin (13) andThe otherThe tube element (12) is integrally brazed in close contact.
[0062]
In addition, as shown in FIG. 10, the concave groove (41) is not formed at both ends of the flat tube (40). This is because, when the end of the flat tube (40) is inserted and arranged in the tube insertion holes (15a) (16a), between the outer peripheral surface of the tube end and the inner periphery of the tube insertion holes (15a) (16a). This is to make no gap. By doing so, the tube (40) and the headers (15), (16) are surely integrated in a liquid-tight state by brazing without forming the tube insertion holes (15a), (16a) in a special shape. be able to.
[0063]
In this embodiment, as shown in FIGS. 8 and 10, the width of the outer fin (44) is set wider than the width of the flat tube (40), and one end of the fin (44) is flat. The tube (40) is arranged in an overhang state so as to coincide with one side edge of the tube (40). The fin (44) has the other end protruding to the windward side. In addition, the fin (44) is provided with a louver (44a) only at the center thereof.
[0064]
The overhang of the fins (44) on the windward side as described above reduces the air-side heat transfer coefficient to gradually form frost, and increases the frost area to improve frost resistance. It is to make it. The reason why the louver (44a) is formed only at the center in the width direction of the fin (44) is to secure the rigidity of the fin (44).
[0065]
【The invention's effect】
A flat tube for a heat exchanger according to the present invention comprises a pair of strip-shaped tube elements arranged in opposition to each other and an inner fin interposed between the two tube elements. The side edge portions are wound around the middle portion in the width direction of the tube element and connected and integrated, and have a roll-up joining edge portion on both side edges in the width direction.
[0066]
Therefore, the flat tube can be reduced in thickness, and the inner fin can be provided to improve the heat transfer coefficient and reduce the fluid diameter, so that both high performance and light weight can be achieved. Can be.
[0067]
In addition, since the flat tube has both surfaces in the thickness direction formed flush or substantially flush over the entire area in the tube width direction including the winding joint edge, the tube insertion hole is formed in a special shape. Without forming a simple slit shape similar to the conventional one, the brazing between the header and the flat tube can be ensured, and the flat tube is inserted and arranged. The work of forming the tube insertion hole of the header can be easily performed. Thus, an easy-to-manufacture and highly reliable flat tube for a heat exchanger, which is excellent in performance on both the air side and the heat exchange medium side and can achieve high performance and light weight, and furthermore, a heat exchanger can be provided. it can.
[Brief description of the drawings]
FIG. 1 is an overall front view of a heat exchanger according to an embodiment of the present invention.
FIG. 2 is a partially enlarged perspective view showing a header and a flat tube of the heat exchanger in a separated state.
FIG. 3 is an enlarged cross-sectional view showing a manufacturing process of the flat tube.
FIG. 4 is an enlarged sectional view taken along line 4-4 of FIG. 2;
FIG. 5 is an enlarged cross-sectional view showing a flat tube manufacturing process according to a modification.
FIG. 6 is an enlarged cross-sectional view of a flat tube according to the modification.
FIG. 7 is an overall front view of a heat exchanger according to another embodiment.
FIG. 8 is an enlarged sectional view taken along line 8-8 in FIG. 7;
9 is an enlarged cross-sectional view of a flat tube used in the heat exchanger shown in FIG.
FIG. 10 is a partially enlarged perspective view showing a header and a flat tube of the heat exchanger shown in FIG. 7 in a separated state.
[Explanation of symbols]
10. Flat tube
10a winding joint edge
11 Tube element
12 Tube element
13 Inner fin
14 Outer fin
15 Header
16 header
30 flat tube
30a winding joining edge
31 tube element
32 tube element
33 Inner fin
40 flat tube
40a winding joining edge

Claims (8)

A first and a second band-shaped tube element arranged in opposition to each other, and a corrugated inner fin interposed between the two tube elements;
By folding both side edges in the width direction of the second tube element on both side edges in the width direction of the first tube element, and folding up the folded portion, the corresponding width side edges of both tube elements can be obtained. A flat tube that is wound around the middle part of the tube element in the width direction and connected and integrated, and has a winding joining edge on both side edges in the width direction,
Both surfaces in the thickness direction of the tube are formed flush or substantially flush over the entire region in the tube width direction including the winding joining edge .
Further, a concave portion for forming a drain concave groove is formed in the first tube element, while the concave portion corresponding portion of the inner fin and the concave portion corresponding portion of the second tube element are formed flat, 3. The flat tube for a heat exchanger according to claim 1, wherein the first tube element, the inner fin, and the second tube element are integrated by brazing in close contact with each other . A plurality of flat tubes arranged in parallel with a predetermined spacing in the thickness direction with outer fins interposed therebetween, and a pair of hollow headers arranged in a communication connection state at both ends of these flat tubes In a heat exchanger with
The flat tube includes first and second strip-shaped tube elements arranged in opposition to each other, and a corrugated inner fin interposed between the two tube elements, and a width of the first tube element. By folding both side edges in the width direction of the second tube element on both side edges in the direction, and folding up the folded portion, the two tube elements are connected and integrated at the both side edges in the width direction, and are formed on both side edges in the width direction. It has a winding joining edge, and both surfaces in the thickness direction are formed flush or substantially flush over the entire tube width direction including the winding joining edge. A concave portion for forming a concave groove for drainage is formed in the first tube element, while a concave portion corresponding to the concave portion of the inner fin and a front portion of the second tube element. Recess corresponding portion is formed flat, in that position, the heat exchanger, characterized in that the first tube element and an inner fin and the second tube element is integrally brazed in a close contact state. 3. A tube insertion hole is formed at intervals along the length direction of each header, and an end of a flat tube is inserted and arranged in the insertion hole, and is joined and connected in a liquid-tight state by brazing. A heat exchanger according to item 1. 4. The outer fin according to claim 2, wherein a width of the outer fin is set to be wider than a width of the flat tube, and one end of the fin is arranged in an overhanging state so as to coincide with one side edge of the flat tube. 5. Heat exchanger. The heat exchanger according to claim 4, wherein the outer fin is configured such that the other end side protrudes toward the windward side. The heat exchanger according to any one of claims 2 to 5, wherein the outer fin is provided with a louver only at a central portion. A car air-conditioning system using the heat exchanger according to claim 2. A room air conditioner using the heat exchanger according to claim 2.

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