Heat exchanger header plate structure
The header plate structure addresses thermal stress in heat exchangers by distributing stress through varying brazing heights and configurations, reducing strain and crack risk in tubes near partition areas.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- T RAD CO LTD
- Filing Date
- 2021-09-27
- Publication Date
- 2026-06-03
AI Technical Summary
Existing heat exchangers with divided cores experience thermal stress and strain between cores due to temperature differences in the heat transfer medium, leading to potential cracks in the flattened tubes near partition portions.
The header plate structure features elongated tube insertion holes with varying heights and brazing configurations, including end and second brazing portions, to distribute thermal stress and reduce strain at critical joints.
The design effectively reduces thermal stress at brazed joints by aligning stress distribution across the brazing lines, minimizing the risk of cracks in flattened tubes near partition areas.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a header plate structure of a heat exchanger optimal for a heat exchanger having cores divided into a plurality, and particularly relates to reducing thermal stress and distortion applied to flat tubes and header plates at boundary positions to be divided.
Background Art
[0002] As a heat exchanger in which cores divided into a plurality are formed in the longitudinal direction of a tank, the following Patent Document 1 is known. As shown in FIGS. 9 and 10, this heat exchanger is formed with cores by a large number of parallel flat tubes 32, and the tips of each flat tube 32 are inserted into tube insertion holes 4 drilled in the bottom surface 10 of a pair of header plates 1. Corrugated fins 33 are arranged between each flat tube 32. And a tank body 21 is fitted onto a pair of header plates 1 to form a tank. As shown in FIG. 11, the tank body 21 is fixed to the header plate 1 by caulking a claw portion 13 provided on the header plate 1 to a small flange 25 of the tank body 21. [[ID=IS]]A pair of partition portions 22 for partitioning a flow path of a heat medium flowing inside the core are formed on the tank body 21. As shown in FIG. 10(B), dummy tube insertion holes 6 are formed in the bottom surface 10 of the header plate 1 at portions where the pair of partition portions 22 of the tank body 21 are located, and flat tubes 32 are inserted into the dummy tube insertion holes 6. No heat medium flows into the flat tubes 32 inserted into the dummy tube insertion holes 6. When the tank body 21 is fitted onto the header plate 1, the longitudinal direction of the tank body 21 is partitioned into a first tank portion 23 and a second tank portion 24 with the dummy tube insertion holes 6 as a boundary. And as shown in FIG. 9, the core portion partitioned by the first tank portion ۲۳ forms a first core 34, and the core portion partitioned by the second tank portion 24 forms a second core 35. Different heat media can be made to flow through the first core 34 and the second core 35, respectively.
Prior Art Document
[0003] [Patent Document 1] Japanese Patent Publication No. 2002-115991 [Overview of the project] [Problems that the invention aims to solve]
[0004] However, in the heat exchanger described in Patent Document 1, if there is a temperature difference in the heat transfer medium flowing into each core 34 and 35, thermal strain will occur between the cores 34 and 35. Then, each time the heat exchanger is operated, thermal stress will be generated between the two cores 34 and 35, and after many years of use, cracks may occur in the flattened tube 32 into which the heat transfer medium flows, which is located near the partition portion 22 of the tank body 21. Therefore, the present invention aims to reduce thermal stress and strain that occur in the flattened tube 32, which is positioned near the partition portion 22 of the tank body 21. [Means for solving the problem]
[0005] The present invention as described in claim 1 is an elongated header plate 1 having a number of flat tube insertion holes 4 formed on its bottom surface 10, which consist of a pair of opposing short sides 2 and a pair of long sides 3 connecting the two short sides 2, The tank body 21 is crimped and fixed to the header plate 1 via a seal ring 31, A flattened tube 32 whose end is inserted through the header plate 1 and whose inserted portion is brazed and fixed to form a core, It is equipped with, The short sides 2 of the numerous tube insertion holes 4 are located in the width direction of the header plate 1, and these tube insertion holes 4 are spaced apart from each other in the longitudinal direction of the header plate 1. In a heat exchanger header plate structure in which the tank body 21 has a pair of partitions 22 that divide it into multiple sections in the longitudinal direction, and among the tube insertion holes 4, the tube insertion holes 4 located between the partitions 22 are formed as dummy tube insertion holes 6, and the core is partitioned at the position of the dummy tube insertion holes 6, A burring 8 is formed on the edge of each tube insertion hole 4, 6, and a flat tube 32 is inserted through each tube insertion hole 4, 6, and the flat tube 32 is joined to the inner surface of the top of the burring 8 of each tube insertion hole 4, 6. At least one of the tube insertion holes 4 has an end brazed portion 8a at both ends of the long side portion 3 and a first brazed portion 8b adjacent to the end brazed portion 8a. Each of these brazed parts 8a and 8b forms a brazed joint line with the flattened tube 32. The header plate structure of a heat exchanger is characterized in that, with respect to the height H from the burring bottom surface 15 in the peripheral area of the tube insertion hole 4 to the positions of each brazed portion 8a, 8b, the height H1 up to the first brazed portion 8b is formed to be lower than the height H2 up to the end brazed portion 8a, and the tube insertion hole 5a is formed to be lower. The present invention as described in claim 2 relates to the header plate structure of the heat exchanger described in claim 1, The tube insertion hole 5a has a second brazing portion 8c located adjacent to the first brazing portion 8b at a position closer to the center, and the brazing portions 8a, 8b, and 8c form a brazed joint line. In this heat exchanger header plate structure, the height H from the burring bottom surface 15 in the area surrounding the tube insertion hole 5a to the positions of each brazed portion 8a, 8b, and 8c is such that the height H1 up to the first brazed portion 8b is lower than the height H3 up to the second brazed portion 8c. The present invention as described in claim 3 is a header plate structure for a heat exchanger as described in claim 2, This is a header plate structure for a heat exchanger in which the height H2 up to the end brazed portion 8a and the height H3 up to the second brazed portion 8c are formed to be the same length. The present invention as described in claim 4 relates to a header plate structure for a heat exchanger as described in any one of claims 1 to 3, The header plate structure of the heat exchanger is such that the height H2 up to the brazed end portion 8a is 1.1 or greater than the height H1 up to the first brazed portion 8b. The present invention as described in claim 5 is a header plate structure for a heat exchanger as described in any one of claims 1 to 4, The tube insertion holes 4, which are arranged adjacent to both sides of the dummy tube insertion hole 6, are formed as end tube insertion holes 5. This is a header plate structure for a heat exchanger in which at least one of the end tube insertion holes 5 is the tube insertion hole 5a. [Effects of the Invention]
[0006] The invention described in claim 1 is a header plate structure for a heat exchanger having a tube insertion hole 5a in which at least one of the tube insertion holes 4 has an end brazed portion 8a at the positions of both ends of the long side portion 3 of the end tube insertion hole 5 and a first brazed portion 8b adjacent to both ends, and each of these brazed portions 8a and 8b forms a brazed joint line with the flat tube 32, and the height H1 from the burring bottom surface 15 in the peripheral area of the end tube insertion hole 5 to the position of each brazed portion 8a and 8b is formed to be longer than the height H2 to the end brazed portion 8a. This structure makes it easier for thermal stress to occur in the first brazed portion 8b, thereby reducing the thermal stress that occurs in the end brazed portion 8a. The invention described in claim 2 is the invention of claim 1, wherein the tube insertion hole 5a has a second brazing portion 8c positioned adjacent to the first brazing portion 8b at a position closer to the center, and each brazing portion 8a, 8b, and 8c forms a brazed joint line, and the height H from the burring bottom surface 15 in the peripheral area of the tube insertion hole 5a to the positions of each brazing portion 8a, 8b, and 8c is such that the height H1 up to the first brazing portion 8b is lower than the height H3 up to the second brazing portion 8c. This structure increases the height H3 from the second brazed section 8c to the brazing line, thereby reducing the thermal stress generated in the second brazed section 8c. The invention described in claim 3 is the invention of claim 2, wherein the height H2 up to the end brazed portion 8a and the height H3 up to the second brazed portion 8c are formed to be the same length. This structure aligns the tip position of the burring 8 of the second brazed portion 8c with the tip position of the burring 8 of the end brazed portion 8a, making it easier for the outer surface of the flattened tube 32 to contact the inner surface of the tube insertion hole 5a due to the expansion of the tube end, and also facilitating the formation of the tube insertion hole 5a of the header plate 1. The invention described in claim 4 is the invention of any one of claims 1 to 3, wherein the height H2 up to the end brazed portion 8a is 1.1 or greater than the height H1 up to the first brazed portion 8b. This structure allows the thermal stress generated at the end brazed portion 8a to be effectively distributed to the first brazed portion 8b, thereby effectively reducing the thermal stress generated at the end brazed portion 8a. The invention described in claim 5 is the invention of any one of claims 1 to 4, wherein tube insertion holes 4 arranged adjacent to both sides of the dummy tube insertion hole 6 are formed as end tube insertion holes 5, and at least one of the end tube insertion holes 5 is the tube insertion hole 5a. This structure further makes it possible to efficiently reduce the stress generated at the joint between the end tube insertion hole 5, which is located adjacent to the dummy tube insertion hole 6 where thermal stress is likely to occur, and the flattened tube 32. [Brief explanation of the drawing]
[0007] Figure 1 is a plan view of the main part of the header plate 1 used in the header plate structure of the present invention. Figure 2 shows the cross-sectional view taken along the arrows IIA-IIA (A) and IIB-IIB (B) in Figure 1. Figure 3 shows the cross-sectional views in the direction of arrows IIIA-IIIA (A), IIIB-IIIB (B), and IIIC-IIIC (C) in Figure 1. FIG. 4 is an explanatory view showing the header plate structure of the present invention. FIG. 5 is a plan view of a main part of the header plate 1 according to the second embodiment of the present invention. FIG. 6 is a plan view of a main part of the header plate 1 according to the third embodiment of the present invention. FIG. 7 is a plan view of a main part of the header plate 1 according to the fourth embodiment of the present invention. FIG. 8 is a plan view of a main part of the header plate 1 according to the fifth embodiment of the present invention. FIG. 9 is a front view of a heat exchanger having a tank with a conventional header plate structure. FIG. 10 is a main part view taken along the X-X arrow in FIG. 9 (A) and a cross-sectional view taken along the B-B arrow in FIG. 10 (A) (B). FIG. 11 is a cross-sectional view taken along the XI-XI arrow in FIG. 10 (A).
BEST MODE FOR CARRYING OUT THE INVENTION
[0008] Next, embodiments of the present invention will be described with reference to the drawings and by way of example. This heat exchanger is suitable for use, for example, in a radiator or the like that cools engine coolant. The tank of this heat exchanger is composed of a tank body 21 and a header plate 1. The tank body 21 is made of a synthetic resin material in this embodiment and is formed in a box shape having an opening on the side connected to the header plate 1. A bottom is formed facing the opening. A small flange 25 bulging outward from the tank body 21 is formed at the edge of the opening. And inside the tank body 21, as an example, a pair of partition portions 22 are arranged facing each other with a distance of about the width of one flat tube 32 in the width direction. The partition portions 22 are formed at the intermediate position in the longitudinal direction of the tank body 21 as shown in FIG. 4 and are formed from the bottom of the tank body 21 toward the bottom surface 10 of the header plate 1. The ends of the partition portions 22 are connected to the bottom surface 10 of the header plate 1 via annular seal rings 31, respectively. The inside of the tank body 21 is divided by the pair of partition portions 22, and a first tank portion 23 and a second tank portion 24 are formed on both sides of the pair of partition portions 22. The header plate 1 is formed in an elongated shape with a planar square shape. On the bottom surface 10 of the header plate 1, as shown in FIG. 1, a plurality of flat tube insertion holes 4 are formed, which are composed of a pair of opposing short side portions 2 and a pair of long side portions 3 connecting between the two short side portions 2. The short side portions 2 of the tube insertion holes 4 are located in the width direction of the header plate 1, and these tube insertion holes 4 are arranged at intervals in the longitudinal direction of the header plate 1. At the position of the intermediate portion in the longitudinal direction of this header plate 1, specifically, at a position corresponding to between a pair of partition portions 22 formed in the tank body 21, a dummy tube insertion hole 6 (composed of a pair of short side portions 2 and a pair of long side portions 3 similar to the tube insertion hole 4) is formed. Stress reduction portions are formed on both sides of the dummy tube insertion hole 6. End tube insertion holes 5 (composed of a pair of short side portions 2 and a pair of long side portions 3 similar to the tube insertion hole 4) are formed there, and the tube insertion holes 4 are arranged in parallel in order on the outside of the stress reduction portions. The inner circumferences of each tube insertion hole 4, end tube insertion hole 5, and dummy tube insertion hole 6 are the same. On the hole edges of each insertion hole 4, 5, 6, a burring 8 protruding toward the inside of the tank body 21 is formed. The burring 8 is smoothly connected with a curved surface between the root of its top and the burring bottom surface 15 of the header plate 𝑙. Near the inside of its top, it has a joining surface 9 formed on a flat surface so as to be easily joined with the flat tube 32. This burring bottom surface 15 exists on the back surface of the bottom surface 10 of the header plate 1, as shown in FIGS. 2 and 3. On the outer periphery of the header plate 1, as shown in FIG. 2(B), an outer peripheral wall rising toward the tank body 21 side is formed, and caulking claws 13 are formed at its tip. As shown in FIG. 3, on the bottom surface 10 where the tube insertion hole 4 is formed, a raised portion 14 rising toward the inside of the tank body 21 is formed. The bottom surface 10 of the raised portion 14 is at a higher position than the bottom surface 10 where the dummy tube insertion hole 6 and the end tube insertion hole 5 are formed. As shown in Figure 1, a groove 11 is formed between the outer peripheral edge of the bottom surface 10 of the raised portion 14 and the outer peripheral wall of the header plate 1. The rigidity of the area of the bottom surface 10 of the raised portion 14 is higher than the rigidity of the bottom surface 10 in which the dummy tube insertion hole 6 and the end tube insertion hole 5 are formed. This heat exchanger has a core formed by arranging a large number of flattened tubes 32 in parallel. Each flattened tube 32 has a vertical central axis 7 passing through its interior center. The ends of the flattened tubes 32 are inserted through each of the insertion holes 4, 5, and 6, and the flattened tubes 32 are fixed to the joint surfaces 9 of the burrings 8 of each insertion part 4, 5, and 6 by brazing. Corrugated fins 33 can be arranged between each of the flattened tubes 32, as shown in Figure 4. As shown in Figure 1, a seal ring 31 is positioned in the groove 11 of the header plate 1 and on the inter-tube sealing surface 12 between the dummy tube insertion hole 6 and the adjacent end tube insertion hole 5. The opening of the tank body 21 is fitted into the header plate 1 via the seal ring 31. The claw portion 13 of the header plate 1 is then crimped to the small flange 25 side of the tank body 21, thereby fixing the tank body 21 and the header plate 1 together. As shown in Figure 4, the pair of partitions 22 are positioned so that the tips of each partition 22 abut against the seal ring 31 at the location of the inter-tube sealing surface 12. The core is divided on both sides in the longitudinal direction of the dummy tube insertion hole 6 by the dummy tube insertion hole 6, the pair of partitions 22 inside the tank body 21, and the flattened tube 32 inserted into the dummy tube insertion hole 6. A first core 34 is located on the first tank section 23 side, and a second core 35 is located on the second tank section 24 side, allowing different heat transfer fluids to flow through these cores 34 and 35. For example, engine coolant can flow through the first core 34, and auxiliary equipment coolant can flow through the second core 35. In the heat exchanger described above, if there is a temperature difference in the heat transfer medium flowing into each core 34 and 35, thermal strain occurs between the cores 34 and 35, and thermal stress is generated between the two cores 34 and 35 each time the heat exchanger is operated. In particular, thermal stress is likely to occur in the flattened tube 32 located near the partition 22 of the tank body 21 that forms the boundary between the two cores 34 and 35. In the stress reduction areas of the bottom surface 10 where the dummy tube insertion holes 6 and end tube insertion holes 5 are formed, the rigidity of the peripheral edges of these insertion holes 5, 6 is made weaker than the rigidity of other areas, so no raised portion 14 is formed. This absorbs the stress generated in the flattened tubes 32 that are inserted through the dummy tube insertion holes 6 and end tube insertion holes 5 located near the partition portion 22 of the tank body 21. The effect becomes more pronounced as the number of end tube insertion holes 5 increases. In this example, three end tube insertion holes 5 are formed adjacent to each side of the dummy tube insertion hole 6. Figures 1 to 4 show a first embodiment of the header plate structure of the present invention. This embodiment has a structure that more effectively reduces thermal stress generated in the stress reduction area near the partition portion 22. In this example, of the three end tube insertion holes arranged in parallel on both sides of the dummy tube insertion hole 6, the tube insertion hole 5a adjacent to the dummy tube insertion hole 6 has end brazed portions 8a formed at both ends of the long side portion 3, and a first brazed portion 8b is formed adjacent to the end brazed portion 8a. These brazed portions 8a and 8b form a brazed joint line with the flattened tube 32. The brazed joint lines of each brazed portion 8a and 8b are formed at the boundary between the axial center side of the vertical central axis 7 of the joint surface 9 and the curved surface of the burring 8 at the contact point between the outer surface of the flattened tube 32 and the joint surface 9 of the burring 8. The brazed joint line of the second brazed portion 8c, which will be described later, is formed at a similar boundary. As described above, the bottom surface 10 of the area surrounding the end tube insertion hole 5 is formed in a planar shape. At the position of the end brazed portion 8a, the burring 8 has a height H2 from the base of the burring bottom surface 15 to the position of the brazed joint line of the end brazed portion 8a (hereinafter referred to as the height H2 to the end brazed portion 8a), and at the position of the first brazed portion 8b, it has a height H1 from the base of the burring bottom surface 15 to the position of the brazed joint line of the first brazed portion 8b (hereinafter referred to as the height H1 to the first brazed portion 8b). As shown in Figures 2 and 3, the height H1 up to the first brazed portion 8b is lower than the height H2 up to the end brazed portion 8a. In other words, in the axial direction of the vertical central axis 7 that passes through the center of the inside of the flattened tube 32, the position of the first brazed portion 8b is located closer to the center in the axial direction of the vertical central axis 7 than the position of the end brazed portion 8a. In this example, as shown in Figures 1 and 2, a second brazed portion 8c is formed in the tube insertion hole 5a adjacent to the first brazed portion 8b, at a position closer to the center. At the position of the second brazed portion 8c, there is a height H3 from the base of the burring bottom surface 15 to the position of the brazed joint line of the second brazed portion 8c (hereinafter referred to as the height H3 to the second brazed portion 8c). The height H1 up to the first brazed portion 8b is lower than the height H3 up to the second brazed portion 8c. In other words, in the axial direction of the vertical central axis 7 passing through the center of the inside of the flattened tube 32, the position of the first brazed portion 8b is located closer to the center in the axial direction of the vertical central axis 7 than the position of the second brazed portion 8c. The end brazed portion 8a, the first brazed portion 8b, and the second brazed portion 8c continuously form a corrugated brazed joint line as shown in Figure 2. As described above, by creating height differences between the burring bottom surface 15 and each brazing section 8a, 8b, and 8c in the brazing line, thermal stress is more likely to occur in the first brazing section 8b, and consequently, the thermal stress generated in the end brazing section 8a and the second brazing section 8c can be reduced. In particular, as shown in Figure 1, when a partition 32a is located in the middle of the longitudinal direction of the flattened tube 32, thermal stress is generated at the joint with the burring 8 at the location where the partition 32a is formed. As described above, by positioning the second brazed portion 8c in a location that matches the position of the partition 32a, thermal stress is more likely to be generated in the first brazed portion 8b, and consequently, the thermal stress generated in the second brazed portion 8c can be reduced. In this example, as shown in Figure 3, the burring 8 of the tube insertion hole 5a has a radius of curvature of R2 at the end brazed portion 8a, and a radius of curvature of R1 at the first brazed portion 8b. The radius of curvature R2 of the end brazed portion 8a is larger than the radius of curvature R1 of the first brazed portion 8b. Furthermore, at the position of the second brazed portion 8c, the radius of curvature of the burring 8 is formed as R3, and the radius of curvature R3 of the second brazed portion 8c is formed to be larger than the radius of curvature R1 of the first brazed portion 8b. As the radii of curvature R1, R2, and R3 of each brazed portion 8a, 8b, and 8c are formed as described above, the tube insertion hole 5a adjacent to the dummy tube insertion hole 6 is formed with the first brazed portion 8b constricted, as shown in Figure 1. In the burring 8 of the tube insertion hole 5a adjacent to the dummy tube insertion hole 6, at the positions of the end brazing portion 8a and the second brazing portion 8c, the circumferential distance from the bottom surface 15 of the burring on the header plate 1 to the joint with the flattened tube 32 is longer than the circumferential distance from the bottom surface 15 of the burring on the header plate 1 to the joint at the position of the first brazing portion 8b. Therefore, the stress generated at the joint between the header plate 1 and the flattened tube 32 due to thermal deformation is distributed across the entire curved surface of the burring 8 at the positions of the end brazing portion 8a and the second brazing portion 8c. Therefore, among the burrings 8 of the tube insertion holes 5a (end tube insertion holes 5 adjacent to the dummy tube insertion holes 6) located near the partition portion 22 in which the core, which is prone to thermal stress, is partitioned, it is possible to efficiently reduce the stress that occurs particularly at the joint between the end brazed portion 8a and the flattened tube 32, where thermal stress tends to concentrate. Preferably, the height H2 up to the end brazed portion 8a and the height H3 up to the second brazed portion 8c are formed to be the same length. In this case, the tip position of the burring 8 of the second brazed portion 8c and the tip position of the burring 8 of the end brazed portion 8a are aligned, making it easier to bring the outer surface of the flattened tube 32 into contact with the inner surface of the tube insertion hole 5a due to the expansion of the tube end, and also making it easier to form the tube insertion hole 5a of the header plate 1. Furthermore, preferably, the height H2 up to the end brazed portion 8a is 1.1 or greater than the height H1 up to the first brazed portion 8b. In this case, the thermal stress generated at the end brazed portion 8a can be effectively distributed to the first brazed portion 8b, thereby effectively reducing the thermal stress generated at the end brazed portion 8a. As shown in Figures 3(A) and (C), it is preferable that the height H2 of the burring 8 of the tube insertion hole 5a to the brazed end portion 8a or the height H3 to the second brazed portion 8c be formed to be higher than the height of the burring 8 of the dummy tube insertion hole 6. Furthermore, it is preferable to make the radius of curvature R2 of the end brazed portion 8a or the radius of curvature R3 of the second brazed portion 8c larger than the radius of curvature R4 of the burring 8 of the dummy tube insertion hole 6. Furthermore, as shown in Figure 3(B), the height of the burring 8 in the dummy tube insertion hole 6 and the height H1 of the burring 8 in the tube insertion hole 5a to the first brazed portion 8b can be made to be approximately the same. Furthermore, the radius of curvature R4 of the burring 8 in the dummy tube insertion hole 6 and the first brazed portion R1 of the tube insertion hole 5a can be made to be approximately the same. The end tube insertion holes 5 that are located away from the dummy tube insertion hole 6 do not have the deformed brazing lines described above, as shown in Figures 1 and 3. The height or radius of curvature of these burrings can be the same as the shape of the burring 8 of the dummy tube insertion hole 6. Figure 5 shows a second embodiment of the header plate structure of the present invention. In this embodiment, the end tube insertion holes 5 from the dummy tube insertion hole 6 to the second closest end tube insertion hole 5 are formed as tube insertion holes 5a having the aforementioned end brazed portion 8a, first brazed portion 8b, and second brazed portion 8c. Figure 6 shows a third embodiment of the header plate structure of the present invention. In this embodiment, all three end tube insertion holes 5 are formed as tube insertion holes 5a having the aforementioned end brazed portion 8a, first brazed portion 8b, and second brazed portion 8c. Figure 7 shows a fourth embodiment of the header plate structure of the present invention. In this embodiment, of the three rows of end tube insertion holes 5, only the second one is formed as a tube insertion hole 5a having the aforementioned end brazed portion 8a, first brazed portion 8b, and second brazed portion 8c. Figure 8 shows a fifth embodiment of the header plate structure of the present invention. As in this embodiment, the tube insertion hole 5a having the end brazed portion 8a, the first brazed portion 8b, and the second brazed portion 8c described above can also be applied to a tube insertion hole 4 located outside the stress reduction area. Preferably, the brazing line is formed to include a second brazing portion 8c. However, it is also possible to form a brazing line with only the end brazing portion 8a and the first brazing portion 8b, without forming the second brazing portion 8c. For example, if no partitions 32a are formed in the flattened tube 32, it is not necessary to form the second brazing portion 8c. Also, if multiple partitions 32a are formed inside the flattened tube 32, multiple second brazing portions 8c may be formed depending on the position of the partitions 32a. The end tube insertion holes 5 are not limited to the number described above, and may consist only of those adjacent to the dummy tube insertion holes 6. These end tube insertion holes 5 can be formed as tube insertion holes 5a having an end brazed portion 8a, a first brazed portion 8b, and a second brazed portion 8c. [Explanation of symbols]
[0009] 1 Header Plate 2 Short side 3 Long side 4 Tube insertion holes 5 End tube insertion holes 5a Tube insertion hole 6. Dummy tube insertion hole 7 Vertical center axis 8 Burring 8a End brazed section 8b First brazed joint 8c Second brazed joint 9 Joint surface 10 Bottom 11 Groove 12. Inter-tube sealing surface 13. Nail area 14 Ridge 15 Burring bottom 21 Tank body 22 Partition section 23. Tank Section 1 24 Second Tank Section 25 Small flange 31 Seal ring 32 Flat tubes 32a Partition 33 corrugated fins 34. First Core 35 Second Core R1, R2, R3, R4 Burling radius of curvature H1, H2, H3: Height from burring base 15 to joint line
Claims
1. An elongated header plate (1) has a bottom surface (10) formed with numerous flattened tube insertion holes (4) consisting of a pair of opposing short sides (2) and a pair of long sides (3) connecting the two short sides (2), The tank body (21) is crimped and fixed to the header plate (1) via a seal ring (31), A flat tube (32) whose end is inserted into a header plate (1) and whose inserted portion is brazed and fixed to form a core, It is equipped with, The short sides (2) of the numerous tube insertion holes (4) are located in the width direction of the header plate (1), and these tube insertion holes (4) are spaced apart from each other in the longitudinal direction of the header plate (1). In a header plate structure of a heat exchanger in which the tank body (21) has a pair of partitions (22) that divide it into multiple sections in the longitudinal direction, and among the tube insertion holes (4), the tube insertion holes (4) located between the pair of partitions (22) are formed as dummy tube insertion holes (6), and the core is partitioned at the position of the dummy tube insertion holes (6), A burring (8) is formed on the edge of each tube insertion hole (4, 6), and a flattened tube (32) is inserted through each tube insertion hole (4, 6), and the flattened tube (32) is joined to the inner surface of the top of the burring (8) of each tube insertion hole (4, 6). At least one of the tube insertion holes (4) has an end brazed portion (8a) at the positions of both ends of the long side portion (3) and a first brazed portion (8b) adjacent to the end brazed portion (8a), Each of these brazed parts (8a, 8b) forms a brazed joint line with the flattened tube (32), The tube insertion hole (5a) has a height (H) from the burring bottom surface (15) in the peripheral area of the tube insertion hole (4) to the position of each brazed portion (8a, 8b), where the height (H1) to the first brazed portion (8b) is formed to be lower than the height (H2) to the end brazed portion (8a). In the tube insertion hole (5a), the radius of curvature (R2) of the curved surface connecting the top of the burring (8) at the position of the end brazed portion (8a) and the base of the burring bottom surface (15) of the header plate (1) is formed to be larger than the radius of curvature (R1) of the curved surface connecting the top of the burring (8) at the position of the first brazed portion (8b) and the base of the burring bottom surface (15) of the header plate (1), characterized in that, in the header plate of a heat exchanger, T structure.
2. In the header plate structure of the heat exchanger according to claim 1, The tube insertion hole (5a) has a second brazing portion (8c) positioned adjacent to the first brazing portion (8b) at a position closer to the center, and each brazing portion (8a, 8b, 8c) forms a brazed joint line. A header plate structure for a heat exchanger in which, with respect to the height (H) from the burring bottom surface (15) in the area surrounding the tube insertion hole (5a) to the position of each brazed part (8a, 8b, 8c), the height (H1) to the first brazed part (8b) is formed to be lower than the height (H3) to the second brazed part (8c).
3. In the header plate structure of the heat exchanger according to claim 2, A header plate structure for a heat exchanger in which the height (H2) up to the end brazed portion (8a) and the height (H3) up to the second brazed portion (8c) are formed to be the same length.
4. In the header plate structure of a heat exchanger according to any one of claims 1 to 3, A header plate structure for a heat exchanger in which the height (H2) up to the end brazed portion (8a) is 1.1 or greater than the height (H1) up to the first brazed portion (8b).
5. In the header plate structure of a heat exchanger according to any one of claims 1 to 4, Tube insertion holes (4) located adjacent to both sides of the dummy tube insertion hole (6) are formed as end tube insertion holes (5). A header plate structure for a heat exchanger in which at least one of the end tube insertion holes (5) is a tube insertion hole (5a).