JP2009229052A - Heat exchanger - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a heat exchanger having a flat tube suppressing change in the shape of the outer periphery caused by a shift of an overlapped section. <P>SOLUTION: The flat tube 10 of the heat exchanger has a curve section 13. At least part of the curve section 13 is constructed by overlapping an outer edge section 22 with the outer side of an inner edge section 21. The inner edge section 21 has a small curve region 102. The small curve region 102 tilts relative to a flat plate section 11 and is defined by a radius greater than a difference between half the thickness d1 of the flat tube 10 and the plate thickness of the outer edge section 22. The small curve section 102 is provided at a position not beyond the center line C1 in the thickness direction of the flat tube 10. The outer edge section 22 extends beyond the center line C1. An end surface 22a of the outer edge section 22 is located in the small curve region 102. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a heat exchanger provided with a flat tube.

  Patent Document 1 discloses a flat tube of a conventional heat exchanger. The flat tube is formed by bending a metal plate into an elongated groove to form first and second members, and both edges in the width direction of the first member are outside the edges in the width direction of the second member. It is manufactured by fitting and overlapping. On the outer peripheral surface of the manufactured flat tube, a step is formed by exposing the end surfaces of both edges in the width direction of the first member. At both ends in the longitudinal direction of the second member, bulges that are bulged and deformed by the thickness of the plate are formed so as to eliminate the step. Thereby, the flat tube has a smooth shape with no stepped portion on the outer peripheral surface only at both ends in the longitudinal direction.

  When producing a heat exchanger, the longitudinal ends of the flat tubes are inserted into the insertion holes of the header and joined together by brazing. In some cases, both ends of the flat tube are fitted into a pair of headers. Before brazing, in order to improve the adhesion between the flat tube and the header, the end portion in the longitudinal direction of the flat tube inserted through the tube insertion hole may be expanded.

Japanese Patent Laid-Open No. 2004-293988

  In the flat tube as described above, when the end portion in the longitudinal direction is widened, a gap between the end surface of the first member and the bulging portion is enlarged, so that the brazing between the flat tube and the header is performed. One problem arises that the heat resistance is likely to deteriorate and leakage of the heat exchanger is likely to occur.

  Further, in the flat tube manufacturing process, the width of the plate may change, or the positions of both ends of the plate may shift. In such a case, the overlapping portion of the flat tube is displaced. As a result, the brazing performance between the flat tube and the header is lowered, and another problem that the leakage failure of the heat exchanger is likely to occur.

  The objective of this invention is providing the heat exchanger provided with the flat tube which suppressed the change of the outer periphery shape resulting from the shift | offset | difference of an overlapping part.

  Another object of the present invention is to provide a heat exchanger that suppresses the occurrence of leakage defects.

  In order to achieve the above object, the present invention employs the following technical means.

  In the heat exchanger having the flat tube (10) in which the two edges (21, 22) of the metal plate (20) overlap at the curved portion (13) at the cross-sectional end, The tube (10) includes an inner edge (21) positioned inside the two edges (21, 22), an outer edge (22) positioned outside the inner edge (21), and an inner edge. A large curved region (103) provided in the portion (21), a small curved region (102) provided in the inner edge (21) and having a smaller curvature than the large curved region (103), and an outer edge (22). And an end face (22a) located on the small curved region (102).

  Thereby, even if a shift | offset | difference arises in an overlapping part for some reason, the change of an outer periphery shape is suppressed. This configuration provides advantages both in a heat exchanger with a swell process and in a heat exchanger without a squeeze process. One advantage is that fluctuations in the gap at the brazed portion with the header are suppressed. As a result, leakage at the brazed portion can be prevented.

  In the invention described in claim 2, the large curved region (103) and the small curved region (102) may be bent from the flat plate portion (11) of the flat tube without reversing the bending direction. As a result, the inner edge has a simple shape as compared to the complicated shape in which the inner edge is bent in both directions. This structure allows a simple manufacturing process.

  In the invention described in claim 3, the small curved region (102) may be a flat surface.

  As in the invention described in claim 4, the large curved region (103) may be provided closer to the distal end side of the inner edge (21) than the small curved region (102).

  In the invention according to claim 5, the inner edge (21) and the outer edge (22) overlap over an angle range of 45 degrees or more, and the small curved region (102) is the thickness of the flat tube (10). A heat exchanger is provided in which the outer edge (22) is provided beyond the center line (C1), the outer edge (22) extending beyond the center line (C1).

  Thereby, even if a shift | offset | difference arises in an overlapping part for some reason, the change of an outer periphery shape is suppressed. As a result, the increase in the gap between the outer periphery of the flat tube and the insertion hole can be suppressed, and the occurrence of leakage failure of the heat exchanger can be suppressed. In this configuration, since slip easily occurs between one edge (21) and the other edge (22), both edges (21, 22) are easily deformed to the outer peripheral side. For this reason, it is advantageous also in the magnifying process.

  In the invention according to claim 6, the heat exchanger has a pair of headers (50, 60) provided with insertion holes (54) into which both longitudinal ends of the flat tube (10) are inserted, and the flat tube (10) includes a pair of flat plate portions (11, 12) and a pair of curved portions (13, 14), wherein the metal plate (20) is bent in the same direction, and the flat tube (10) is fitted. It has a widened portion (15, 16) whose diameter is increased in the vicinity of the hole (54), the small curved region (102) is inclined with respect to the flat plate portion (11), and the thickness of the flat tube (10) ( A heat exchanger having a radius greater than the difference between half of d1) and the thickness of the other edge (22) is provided.

  Thereby, even if a shift | offset | difference arises in an overlapping part for some reason, the change of an outer periphery shape is suppressed. As a result, the increase in the gap between the outer periphery of the flat tube and the insertion hole can be suppressed, and the occurrence of leakage failure of the heat exchanger can be suppressed. In this configuration, since slip easily occurs between one edge (21) and the other edge (22), both edges (21, 22) are easily deformed to the outer peripheral side. For this reason, it is advantageous also in the magnifying process.

  As in the invention described in claim 7, the opening shape of the portion corresponding to the one curved portion (13) in the fitting hole (54) may be a semicircular shape. Thereby, an outer edge part (22) can be smoothly deformed along the opening edge part of a fitting hole (54) in an opening process, and it is between a flat tube (10) and a header (50, 60). Adhesion can be improved.

  As in the invention described in claim 8, the plate thickness of the outer edge (22) may gradually decrease toward the end face (22a) of the outer edge (22). Thereby, the change of an outer periphery shape is suppressed.

  As in the ninth aspect of the invention, the inner edge (21) may extend beyond the center line (C1). Thereby, when a plurality of flat tubes (10) are assembled, a force in a direction in which the gap between the two edge portions (21, 22) is narrowed by applying a compressive load from the outside in the thickness direction of the flat tubes (10) works. . Therefore, since the adhesiveness between both edge parts (21, 22) increases, the brazing property of the flat tube (10) can be improved.

  As in the invention described in claim 10, the plate thickness of the inner edge (21) may gradually decrease toward the end face (21a) side of the inner edge (21). Thereby, since the level | step difference formed in the inner surface of a flat tube (10) can be made small, opening of a mouth becomes easy. Moreover, since the internal cross-sectional area of a flat tube (10) can be enlarged, the water flow resistance of a flat tube (10) can be reduced.

  As in the invention described in claim 11, the facing angle (θ) formed by the end surface (22a) of the outer edge portion (22) and the outer surface (21b) of the inner edge portion (21) may be an acute angle. This facilitates the formation of a melted brazing material or flux fillet between the end surface (22a) and the outer surface (21b), and therefore brazing between the flat tube (10) and the header (50, 60). The sex can be further improved.

  As in the invention described in claim 12, the metal plate (20) may be manufactured using a clad material having a brazing material layer formed on at least one surface.

  In addition, the code | symbol in the bracket | parenthesis of each said means has shown an example of the corresponding relationship with the specific means as described in embodiment mentioned later.

The whole structure of the radiator in 1st Embodiment is shown, (a) is a front view, (b) is a side view. FIG. 2 is a partial cross-sectional view illustrating a configuration of a radiator cut along a line II-II in FIG. It is a front view which shows the structure of a core subassembly. It is a top view which shows the structure of a core plate. It is a figure which shows the structure which looked at the flat tube in the thickness direction. It is sectional drawing which shows the structure of the pipe part of the flat tube cut | disconnected by the VI-VI line of FIG. It is sectional drawing which shows the structure of the VII part of FIG. It is sectional drawing which shows the structure of the lip expansion part of the flat tube cut | disconnected by the VIII-VIII line | wire of FIG. It is sectional drawing which shows the structure of the IX part of FIG. It is sectional drawing which shows the lip expansion part of the flat tube in 2nd Embodiment. It is sectional drawing which shows the opening expansion part of the flat tube in 3rd Embodiment. It is sectional drawing which shows the flat tube in 4th Embodiment. It is a partial expanded sectional view which shows the XIII part of FIG. It is an expanded sectional view showing the modification of a 4th embodiment. It is an expanded sectional view showing the modification of a 4th embodiment. It is an expanded sectional view showing the modification of a 4th embodiment. It is an expanded sectional view showing the modification of a 4th embodiment. It is an expanded sectional view showing the modification of a 4th embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1A is a front view showing the overall configuration of the radiator 1 as a heat exchanger in the present embodiment, and FIG. 1B is a side view of the radiator 1. FIG. 2 is a partial cross-sectional view showing a configuration in which the portion A of the radiator 1 is cut along the line II-II in FIG. FIG. 3 is a front view showing the configuration of the core subassembly 5 of the radiator 1. The vertical direction in FIGS. 1A, 1B, 2 and 3 generally represents the vertical vertical direction. As shown in FIG. 1A, FIG. 1B, FIG. 2 and FIG. 3, the radiator 1 includes a core sub formed by integrally joining a plurality of components made of, for example, aluminum alloy by brazing. The assembly 5 includes a pair of tanks 52 and 62 made of, for example, resin and attached to the core subassembly 5. The tank 52 is provided with an inlet 53 through which engine cooling water flows from the outside, and the tank 62 is provided with an outlet 63 through which engine cooling water flows out.

  The core subassembly 5 has a core portion 40 that performs heat exchange between engine coolant and air. The core portion 40 includes a plurality of flat tubes 10 that extend in a substantially vertical direction and distribute engine cooling water, and a plurality of corrugated fins 30 that are thermally connected to the flat tubes 10 and increase a heat transfer area for air. It has an alternately stacked structure. A pair of inserts (side plates) 41 and 42 that reinforce the mechanical strength of the core portion 40 are provided at both end portions on the outer side in the stacking direction of the core portion 40.

  The core subassembly 5 is provided on the upper end side of the core portion 40 and is provided on the lower end side of the core plate 51 and the core portion 40 together with the tank 52 and the lower header 60 together with the tank 62. And a core plate 61.

  FIG. 4 is a top view showing the configuration of the core plate 51. As shown in FIG. 4, the core plate 51 is formed with a plurality of insertion holes 54 into which the longitudinal ends of the stacked flat tubes 10 are respectively inserted. The insertion hole 54 includes a pair of straight line portions parallel to each other and a pair of semicircular arc portions that connect the ends of both straight line portions and bend outward in a semicircular arc shape, and is generally flat and substantially flat. It has an oval opening shape.

  FIG. 5 shows a configuration in which the flat tube 10 is viewed in the thickness direction. As shown in FIG. 5, the flat tube 10 includes a tube portion 17 formed in a cylindrical shape having substantially the same diameter, and a trumpet formed at both ends in the longitudinal direction of the tube portion 17 and expanded in diameter toward the distal end side in the longitudinal direction. Shaped magnifying portions 15 and 16. The widened portions 15 and 16 are formed so that the both ends of the flat tube 10 in the longitudinal direction are inserted into the fitting holes 54 of the core plates 51 and 61, respectively, and then the both ends of the flattened portions 15 and 16 are spread over the entire circumference using a widening jig. It is formed by spreading. Since the widened portions 15 and 16 are formed, the adhesion between the flat tube 10 and the opening end portion of the insertion hole 54 is enhanced and the gap is reduced, so that the gap between the flat tube 10 and the core plate 51 is reduced. The brazing performance of the machine is improved.

  6 is a cross-sectional view showing the configuration of the tube portion 17 of the flat tube 10 cut along the line VI-VI in FIG. As shown in FIG. 6, the flat tube 10 has a flat, substantially oval cross-sectional shape. The flat tube 10 is formed using, for example, a single metal plate 20 having a three-layer structure. The metal plate 20 is manufactured using a clad material having a brazing material layer, a core material layer, and a sacrificial material layer, all formed of an aluminum alloy, for example. The flat tube 10 is formed by bending the metal plate 20 in the same direction so that the brazing material layer, the core material layer, and the sacrificial material layer are arranged in this order from the outside in the radial direction.

  The flat tube 10 connects a pair of flat plate portions 11 and 12 facing each other, and side end portions of the flat plate portions 11 and 12, and a pair of curved portions 13 and 14 that are curved in a substantially semi-cylindrical shape protruding outward. And have. The flat tube 10 has a maximum width in the vicinity of the center line C1 in the thickness direction.

  FIG. 7 is a cross-sectional view showing the configuration of the VII part in FIG. In FIG. 7, the opening shape of the insertion hole 54 is indicated by a broken line. As shown in FIG. 7, the bending portion 13 includes at least an overlapping region 100 in which the other edge (outer edge) 22 is overlapped on the outer side of one edge (inner edge) 21 of the metal plate 20. Has in part. In the overlapping region 100, the inner surface 22b of the outer edge 22 and the outer surface 21b of the inner edge 21 are joined by brazing.

  The outer edge 22 extends along the outer surface 21b of the inner edge 21 and exceeds the center line C1. In the front end region 101 of the outer edge 22, the plate thickness gradually decreases toward the end surface 22 a side. The plate thickness ratio between the plate thickness t1 in the region other than the tip region 101 and the plate thickness t2 (<t1) in the vicinity of the end surface 22a is set to, for example, 50% or more. However, if the plate thickness ratio is made small, it may be difficult to form the metal plate 20, so that the plate thickness ratio is preferably set to about 60 to 70% in consideration of the workability of the metal plate 20. The substantially entire region of the outer edge 22 is curved with a radius substantially equal to half the thickness of the flat tube 10 (the distance between the outer surface of the flat plate portion 11 and the outer surface of the flat plate portion 12) d1.

  The inner edge 21 extends along the inner surface 22b of the outer edge 22 and exceeds the center line C1. The end surface 21 a of the inner edge portion 21 is located in the vicinity of the boundary between the flat plate portion 12 and the bending portion 13. The inner edge portion 21 is connected to the flat plate portion 11 continuously and smoothly, and is inclined with respect to the flat plate portion 11 and has a small curved region 102 having a relatively small curvature (relatively large radius) with a center line C1. It is prepared for a position that does not exceed. Further, the inner edge portion 21 is provided across the center line C1 on the end surface 21a side of the small curved region 102, and has a large curvature region 103 having a larger curvature (a smaller radius than the small curved region 102) than the small curved region 102. It has. The radius of the large curved region 103 is substantially equal to the difference between half of the thickness d1 of the flat tube 10 and the plate thickness t1 of the outer edge portion 22, and the radius of the small curved region 102 is larger than that. The small curved region 102 may include a plane portion having a curvature of 0 and a radius of infinity.

  The end surface 22 a of the outer edge 22 is located on the outer surface 21 b of the small curved region 102. The space between the end face 22a and the outer surface 21b of the portion adjacent to the end face 22a is substantially vertical.

  Here, since the flat tube 10 is formed by bending the metal plate 20 in the same direction, the region protruding inward is formed in both the inner edge 21 and the outer edge 22. Absent. As a result, the large curved region 103 and the small curved region 102 are bent from the flat plate portion 11 of the flat tube 10 without reversing the bending direction.

  FIG. 8 is a cross-sectional view showing the configuration of the widened portion 15 of the flat tube 10 cut along the line VIII-VIII in FIG. FIG. 9 is a cross-sectional view showing the configuration of the IX portion of FIG. As shown in FIGS. 8 and 9, the diameter of the mouth expanding portion 15 is larger than that of the pipe portion 17 shown in FIGS. 6 and 7. Thereby, the cross-sectional shape at the widened portion 15 of the flat tube 10 is deformed following the opening shape of the insertion hole 54. In the widened portion 15, the flat plate portions 11, 12, the curved portion 13, and the curved portion 14 (not shown in FIG. 9) are inserted into the insertion holes 54 except for the gap portion 25 formed in the vicinity of the end surface 22 a of the outer edge portion 22. It comes in close contact with the opening end of the.

  In the widened portion 15, the end surface 21 a of the inner edge 21 and the end surface 22 a of the outer edge 22 are relatively close to each other by expanding the flat tube 10. 100 is narrower. Further, the inner edge 21 of the portion that is in close contact with the outer edge 22 other than the tip region 101 is deformed into an opening shape of the insertion hole 54 and a shape that follows the outer edge 22, so that the small curved region 102 is also narrowed. Yes.

  Next, the manufacturing method of the radiator 1 of this embodiment is demonstrated. First, a plurality of strip-shaped metal plates 20 are manufactured using a clad material having a three-layer structure of a brazing material layer, a core material layer, and a sacrificial material layer. At this time, one edge of the metal plate 20 is processed so that the plate thickness gradually decreases toward the end face side. Next, the metal plate 20 is bent in the same direction to form a plurality of flat tubes 10 each having a pair of flat plate portions 11 and 12 and a pair of curved portions 13 and 14 (tube forming step). At this time, an overlapping region 100 in which the inner edge portion 21 and the outer edge portion 22 of the metal plate 20 are overlapped is formed in one curved portion 13. Since the widened portions 15 and 16 are not formed in the flat tube 10 at this stage, the flat tube 10 has a tubular shape having the entire cross-sectional shape of the tube portion 17 shown in FIGS. 6 and 7 in the longitudinal direction. Formed. That is, in the entire longitudinal direction, the inner edge portion 21 of the flat tube 10 includes the small curved region 102, and the end surface 22 a of the outer edge portion 22 is located on the outer surface 21 b of the small curved region 102.

  Next, a plurality of flat tubes 10 and a plurality of corrugated fins 30 formed in separate steps are alternately stacked to produce an assembly of the core portion 40 (core assembling step). In the core assembling step, a predetermined compressive load is applied to the flat tube 10 and the corrugated fin 30 from the outside in the thickness direction of the flat tube 10.

  Next, the core plates 51 and 61 are assembled to the core portion 40 to produce an assembly of the core subassembly 5 (core plate assembling step). In the core plate assembling step, both longitudinal ends of the flat tube 10 are fitted into the plurality of fitting holes 54 formed in the core plates 51 and 61, respectively. Since the flat tube 10 has a smaller diameter than the insertion hole 54, a gap is formed between the outer peripheral surface of the flat tube 10 and the opening end of the insertion hole 54 (see FIG. 7).

  Next, the both ends in the longitudinal direction of the flat tube 10 fitted into the fitting hole 54 are widened in a trumpet shape using a widening jig to form widened portions 15 and 16 (a widening step). As shown in FIG. 9, the cross-sectional shapes of the widened portions 15 and 16 are deformed following the opening shape of the insertion hole 54, and the adhesion between the flat tube 10 and the core plates 51 and 61 is enhanced. On the other hand, in the tube portion 17 of the flat tube 10, the cross-sectional shape before the magnifying process is generally maintained. Here, the lip expansion jig has a substantially similar cross-sectional shape to the inner peripheral surface of the flat tube 10. That is, the cross-sectional shape of the magnifying jig is generally oval as a whole, and has notches corresponding to the steps formed in the vicinity of the end surface 21 a of the inner edge 21.

  Next, the assembly of the core subassembly 5 is heated to melt the brazing material layer, and the components are brazed (brazing step). At this time, since the adhesion between the flat tube 10 and the core plates 51 and 61 is enhanced by the widened portions 15 and 16, the occurrence of brazing defects can be suppressed.

  Next, the resin tanks 52 and 62 are assembled to the core subassembly 5 (resin tank assembly step). Through the above steps, the radiator 1 shown in FIG. 1 is manufactured.

  In the present embodiment, the inner edge 21 of the flat tube 10 includes the small curved region 102 before the magnifying step, and the end surface 22a of the outer edge 22 is located on the outer surface 21b of the small curved region 102. Thereby, even if a shift | offset | difference arises in an overlapping part for some reason, the change of an outer periphery shape is suppressed. In addition, since slip easily occurs between the outer edge portion 22 and the inner edge portion 21, the outer edge portion 22 and the inner edge portion 21 can be easily deformed to the outside when the mouth is expanded. For this reason, the outer peripheral surface of the flat tube 10 and the opening end portion of the fitting hole 54 can be reliably brought into close contact with each other in the widening step, and the gap can be minimized. Therefore, the brazing property between the flat tube 10 and the core plates 51 and 61 can be improved, and the occurrence of leakage failure of the radiator 1 can be suppressed.

  Moreover, in this embodiment, the plate | board thickness of the front-end | tip area | region 101 of the outer side edge part 22 is reducing gradually toward the end surface 22a side. For this reason, the inclination angle with respect to the flat plate portion 11 in the small curved region 102 of the inner edge portion 21 can be reduced, and the outer edge portion 22 and the inner edge portion 21 are further easily deformed when the mouth is expanded. Moreover, since the plate | board thickness in the end surface 22a can be made thin, the clearance gap part 25 formed between the flat tube 10 after an opening process and the opening edge part of the insertion hole 54 can be made still smaller. Therefore, the brazing property between the flat tube 10 and the core plates 51 and 61 can be further improved.

  Furthermore, in the present embodiment, the outer edge 22 extends beyond the center line C <b> 1 that takes the maximum width of the flat tube 10. For this reason, the outer edge portion 22 is engaged with the inner edge portion 21 in the tube forming step. Therefore, even if the residual stress of the other curved portion 14 is removed by heating in the brazing step, it is possible to prevent the joint portion between the outer edge portion 22 and the inner edge portion 21 from opening.

  In the present embodiment, the inner edge 21 extends beyond the center line C1. For this reason, when a compressive load is applied to the flat tube 10 from the outside in the thickness direction in the core assembling step, the gap between the outer edge 22 and the inner edge 21 that exceeds the center line C1 is narrowed. The force of the direction to work comes to work. Therefore, since the adhesiveness between the inner edge part 21 and the outer edge part 22 increases, the brazing property at the curved part 13 of the flat tube 10 is improved, and the leakage failure of the flat tube 10 can be prevented.

  Furthermore, in this embodiment, the opening end part corresponding to the curved part 13 among the insertion holes 54 of the core plates 51 and 61 has a semicircular shape. For this reason, the outer edge 22 can be smoothly deformed along the opening end of the insertion hole 54, and the adhesion between the outer surface of the outer edge 22 and the opening end of the insertion hole 54 can be improved. Therefore, the brazing property between the flat tube 10 and the core plates 51 and 61 can be improved.

  By the way, as a conventional flat tube, in order to relieve the step formed near the end face of the outer edge part, there is one in which the inner edge part of the overlapping region is recessed inward by the plate thickness. In this flat tube, deformation in the direction in which the gap in the vicinity of the step expands due to widening of the mouth, and thus brazing between the flat tube and the core plate may be deteriorated. Further, the flat tube as described above has a problem in that the metal plate needs to be bent minimally, so that the tube forming process becomes complicated and the manufacturing cost increases.

  On the other hand, since the flat tube 10 of the present embodiment is formed by bending the metal plate 20 in the same direction, no recessed portion is formed. For this reason, since a clearance gap does not expand by mouth opening, the fall of brazing property can be suppressed. Moreover, in this embodiment, since a minimum bending process is unnecessary, the manufacturing process of the flat tube 10 can be simplified and manufacturing cost can be reduced.

(Second Embodiment)
FIG. 10 shows a second embodiment in the vicinity of the curved portion 13 of the widened portion 15 of the flat tube 10. FIG. 10 shows a cross section corresponding to FIG. As shown in FIG. 10, the end surface 22a of the outer edge 22 is formed so that the outer peripheral side protrudes in the circumferential direction more than the inner peripheral side. Thereby, the facing angle θ between the end surface 22a and the outer surface 21b of the inner edge 21 is an acute angle (θ <90 °). For this reason, in the brazing step, a fillet made of molten brazing material or flux is easily formed between the end surface 22a and the outer surface 21b. Therefore, the brazing property between the flat tube 10 and the core plates 51 and 61 is improved, and the leakage failure of the radiator 1 can be prevented.

  In addition, by forming the fillet, the molten brazing material and the flux easily enter the joint portion between the outer edge portion 22 and the inner edge portion 21 by capillary action. Therefore, the brazing property at the curved portion 13 of the flat tube 10 is improved, and the leakage failure of the flat tube 10 can be prevented.

(Third embodiment)
FIG. 11 shows a third embodiment in the vicinity of the curved portion 13 of the widened portion 15 of the flat tube 10. FIG. 11 shows a cross section corresponding to FIG. As shown in FIG. 11, the tip region 104 of the inner edge 21 is formed so that the plate thickness gradually decreases toward the end surface 21a side. The plate thickness ratio between the plate thickness t1 in the region other than the tip region 104 and the plate thickness t3 (<t1) in the vicinity of the end surface 21a is set to, for example, 50% or more. However, if the plate thickness ratio is made small, it may be difficult to form the metal plate 20, so that the plate thickness ratio is preferably set to about 60 to 70% in consideration of the workability of the metal plate 20.

  According to this embodiment, the level | step difference of the flat tube 10 inner surface formed in the end surface 21a vicinity becomes small. For this reason, the notch provided in a lip expansion jig can be reduced in size or omitted, and lip expansion is facilitated. Therefore, the manufacturing process of the heat exchanger can be simplified and the manufacturing cost can be reduced. Moreover, since the inner cross-sectional area (flow-path cross-sectional area) of the flat tube 10 can be enlarged, the water flow resistance of the flat tube 10 can be reduced.

(Fourth embodiment)
A fourth embodiment will be described with reference to FIGS. 12 and 13. The flat tube 810 is a tube with an inner fin. The flat tube 810 includes a cylindrical member 820 constituting an outer shell, and a corrugated inner fin 825 provided in the cylindrical member 820. The tubular member 820 has an oval cross section and provides a flow path. The cylindrical member 820 includes a first flat plate portion 811 and a second flat plate portion 812 that are opposed in parallel in the minor axis direction. The cylindrical member 820 includes a first arcuate curved portion 813 and a second arcuate curved portion 814 that protrude outward in the major axis direction and are formed in an approximately arc shape. The inner fin 825 increases the heat transfer area. Further, both end portions of the inner fin 825 are in close contact with the inner circumferential surfaces of the first arc-shaped curved portion 813 and the second arc-shaped curved portion 814. Further, the remaining portion of the inner fin 825 is formed in a wave shape and is in contact with the first flat plate portion 811 and the second flat plate portion 812. The cylindrical member 820 and the inner fin 825 are formed of a continuous strip material. The cylindrical member 820 forms a closed cylinder by overlapping two edges at one end in the major axis direction. In this embodiment, the boundary region between the cylindrical member 820 and the inner fin 825 provides one edge 821.

  An outer edge 822 is superimposed on the outer side of the inner edge 821. A part of the inner edge 821 has a flat region 802 that is inclined with respect to the major axis direction of the flat tube 810. The planar region 802 can be replaced with a small curved region, but provides advantages due to its shape. The planar region 802 is located near the first flat plate portion 811. The tip of the outer edge 822 is positioned on the planar region 802. The tip region of the outer edge 822 is formed in a flat plate shape along the flat region 802. Planar region 802 is positioned below the tip of outer edge 822. A thin plate portion 830 having a gradually reduced thickness is provided at the tip region of the outer edge portion 822. The thin plate portion 830 is formed by an outer slope.

  The planar region 802 suppresses the amount of outward protrusion of the outer edge 822 tip. Further, the thin plate portion 830 also suppresses the amount of protrusion of the outer edge 822 to the outside of the tip. The position of the tip of the outer edge 822 is shifted due to an error in the manufacturing process. Therefore, the width of the planar region 802 in the circumferential direction is determined so that the tip is not located outside the planar region 802 in consideration of the range where the tip is displaced.

  A modification of the fourth embodiment will be described with reference to FIGS. 14 to 18 show modified examples of the thin plate portion 830. As illustrated in FIG. 14, inclined surfaces may be provided on both sides of the distal end region of the outer edge 822. In this case, the thin plate portion 830 is provided by a cross-sectional shape that can be called a double taper shape or a trapezoidal shape. As illustrated in FIG. 15, the thin plate portion 830 may be provided by a triangular cross-sectional shape. The thin plate portion 830 can also be provided by a curved surface provided in the distal end region of the outer edge portion 822. 16 to 18 show the thin plate portion 830 formed of a curved surface.

(Other embodiments)
In the above embodiment, an example in which the end face 22a of the outer edge 22 is located on the small curved region 102 of the inner edge 21 in both the pipe portion 17 and the mouth widening portions 15 and 16 has been described. In the portions 15 and 16, the end surface 22 a of the outer edge portion 22 may be located on the large curved region 103 of the inner edge portion 21.

  In the above embodiment, the present invention is applied to the longitudinal flow radiator 1 in which the flat tube 10 extends in the vertical direction. However, the present invention is applied to a transverse flow radiator in which the flat tube extends in the horizontal direction and other heat exchangers. The invention may be applied.

DESCRIPTION OF SYMBOLS 1 Radiator 10 Flat tube 11, 12 Flat plate part 13,14 Curved part 15,16 Widening part 17 Pipe part 20 Metal plate 21 Inner peripheral edge 21a, 22a End surface 21b Outer peripheral surface 22 Outer peripheral edge 22b Inner peripheral side Surface 40 Core 50 Upper header 52, 62 Tank 54 Insertion hole 60 Lower header 100 Overlapping area 101, 104 Tip area 102 Small curve area 103 Large curve area

Claims (12)

In the heat exchanger having a flat tube (10) in which the two edges (21, 22) of the metal plate (20) overlap in the curved portion (13) at the end of the cross section,
The flat tube (10)
An inner edge (21) located on the inner side of the two edges (21, 22);
An outer edge (22) located outside the inner edge (21);
A large curved region (103) provided in the inner edge (21);
A small curved region (102) provided on the inner edge (21) and having a smaller curvature than the large curved region (103);
A heat exchanger comprising: an end face (22a) provided on the outer edge (22) and positioned on the small curved region (102).   The said large curvature area | region (103) and the said small curvature area | region (102) are bent without reversing the bending direction from the flat plate part (11) of the said flat tube, The said 1st aspect is characterized by the above-mentioned. Heat exchanger.   The heat exchanger according to claim 1 or 2, wherein the small curved region (102) is a plane.   The heat exchange according to any one of claims 1 to 3, wherein the large curved region (103) is provided closer to the distal end side of the inner edge (21) than the small curved region (102). vessel. The inner edge (21) and the outer edge (22) overlap over an angular range of 45 degrees or more;
The small curved region (102) is provided at a position not exceeding the center line (C1) in the thickness direction of the flat tube (10),
The heat exchanger according to any one of claims 1 to 4, wherein the outer edge (22) extends beyond the center line (C1). The heat exchanger has a pair of headers (50, 60) having insertion holes (54) into which both ends in the longitudinal direction of the flat tube (10) are inserted.
The flat tube (10) is formed by bending the metal plate (20) in the same direction, and includes a pair of flat plate portions (11, 12) and a pair of curved portions (13, 14).
The flat tube (10) has a widened portion (15, 16) whose diameter is increased in the vicinity of the insertion hole (54),
The small curved region (102) is inclined with respect to the flat plate portion (11), and a difference between a half thickness (d1) of the flat tube (10) and a plate thickness of the other edge portion (22). The heat exchanger according to claim 5, wherein the heat exchanger has a larger radius.   The heat exchanger according to claim 6, wherein an opening shape of a portion of the insertion hole (54) corresponding to the one curved portion (13) is a semicircular shape.   The plate | board thickness of the said outer side edge part (22) is decreasing gradually toward the end surface (22a) side of the said outer side edge part (22), The one of Claim 1 thru | or 7 characterized by the above-mentioned. Heat exchanger.   The heat exchanger according to any one of claims 1 to 8, wherein the inner edge (21) extends beyond the center line (C1).   The plate thickness of the inner edge (21) is gradually reduced toward the end face (21a) side of the inner edge (21). Heat exchanger.   11. The facing angle (θ) formed by the end face (22a) of the outer edge (22) and the outer surface (21b) of the inner edge (21) is an acute angle. The heat exchanger according to crab.   The heat exchanger according to any one of claims 1 to 11, wherein the metal plate (20) has a brazing material layer formed on at least one surface.

Images