Heat exchanger header plate structure

Abstract

The present invention relates to a header plate structure of a heat exchanger having a core divided into a plurality, wherein thermal stress and distortion applied to flat tubes and a header plate of the header plate structure are reduced. In the present invention: flat tubes 32 are inserted through tube insertion holes 4, 5, 6 formed in a header plate 1 and having burrings 8; the flat tubes 32 are joined at the inner surfaces of the burrings 8 near top parts 8a of the burrings 8; a burring 8 of height H1 is formed along the long side 3 of a dummy tube insertion hole 6, a burring 8 of height H2 is formed along the long side 3 of an end tube insertion hole 5 adjacent to the dummy tube insertion hole 6; and the height H2 of the burring 8 of the end tube insertion hole 5 is formed so as to be taller than the height H1 of the burring 8 of the dummy tube insertion hole 6.

Description

[Technical Field]

[0001] The present invention relates to a header plate structure for a heat exchanger that is optimal for a heat exchanger having a multi-section core, and more particularly to a structure that reduces thermal stress and distortion on the flat tubes and header plate. [Background technology]

[0002] A heat exchanger in which a core divided into a plurality of sections is formed in the longitudinal direction of a tank is known from Patent Document 1 below. 5 and 6, this heat exchanger has a core formed by a large number of parallel-arranged flat tubes 32, and the tip of each flat tube 32 is inserted into a tube insertion hole 4 drilled in the bottom surface 10 of a pair of header plates 1. Corrugated fins 33 are arranged between each flat tube. The tank is formed by fitting a tank body 21 onto the pair of header plates 1. As shown in Figure 7, the tank body 21 is fixed to the header plate 1 by crimping the claws 13 provided on the header plate 1 onto the small flanges 25 of the tank body 21. The tank body 21 is formed with a pair of partitions 22 that divide the flow path of the heat medium that flows inside the core. 6(B), in the portion where the pair of partition portions 22 of the tank body 21 are located, dummy tube insertion holes 6 are formed in the bottom surface 10 of the header plate 1, and flat tubes 32 are inserted into the dummy tube insertion holes 6. The heat transfer medium does not flow into the flat tubes 32 inserted into the dummy tube insertion holes 6. When the tank body 21 is fitted into 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 the boundary. 5, the portion of the core partitioned by the first tank portion 23 forms a first core 34, and the portion of the core partitioned by the second tank portion 24 forms a second core 35. It becomes possible to circulate different heat transfer media through the first core 34 and the second core 35, respectively. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2002-115991 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the heat exchanger described in Patent Document 1, if there is a temperature difference between the heat medium flowing into each core 34, 35, thermal strain occurs between the cores 34, 35. Then, every time the heat exchanger is operated, thermal stress occurs between the cores 34, 35, and there is a risk that cracks will occur in the flat tubes 32 into which the heat medium flows, which are arranged near the partition 22 of the tank body 21, after long-term use. Therefore, an object of the present invention is to reduce the thermal stress and distortion that occurs in the flat tubes 32 arranged in the vicinity of the partition 22 of the tank body 21. It is necessary to ensure a sufficient sealing surface for disposing the seal ring 31 at the portion of the bottom surface 10 of the header plate 1 where the pair of partition portions 22 of the tank body 21 are located. [Means for solving the problem]

[0005] The present invention as set forth in claim 1 comprises an elongated header plate 1 having a pair of opposing short side portions 2 and a pair of long side portions 3 connecting the short side portions 2, and a number of flat tube insertion holes 4 formed in a bottom surface 10; a tank body 21 that is fixed to the header plate 1 by crimping via a seal ring 31; a flat tube 32 having an end inserted into the header plate 1 and having the inserted portion fixed by brazing to form a core; Equipped with the short sides 2 of the numerous tube insertion holes 4 are positioned in the width direction of the header plate 1, and the tube insertion holes 4 are spaced apart from one another in the longitudinal direction of the header plate 1; The tank body 21 has a pair of partitions 22 that divide the tank body 21 into a plurality of sections in the longitudinal direction, and among the tube insertion holes 4, the tube insertion holes 4 arranged between the partitions 22 are formed as dummy tube insertion holes 6, and a core is divided at the positions of the dummy tube insertion holes 6. In this header plate structure of a heat exchanger, The tube insertion holes 4 arranged adjacent to both sides of the dummy tube insertion hole 6 are formed as end tube insertion holes 5, A flat tube 32 is inserted into each of the tube insertion holes 4, 5, and 6, and burring 8 is formed on the hole edge of each of the tube insertion holes 4, 5, and 6, and the flat tube 32 is joined to the inner surface of each of the tube insertion holes 4, 5, and 6 near the top 8a of the burring 8. Burring 8 having a height H1 is formed on the long side portion 3 of the dummy tube insertion hole 6, Burring 8 having a height H2 is formed on the long side 3 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, This is a header plate structure for a heat exchanger, characterized in that the height H2 of the burring 8 of the end tube insertion hole 5 is formed higher than the height H1 of the burring 8 of the dummy tube insertion hole 6. The present invention as set forth in claim 2 provides the header plate structure of the heat exchanger as set forth in claim 1, In this heat exchanger header plate structure, the ratio of the height H1 of the burring 8 of the dummy tube insertion hole 6 to the height H2 of the burring 8 of the end tube insertion hole 5 is H2 / H1≧1.5. [Effects of the Invention]

[0006] The invention described in claim 1 has a burring 8 of height H1 formed on the long side 3 of the dummy tube insertion hole 6, and a burring 8 of height H2 formed on the long side 3 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, so that the height H2 of the burring 8 of the end tube insertion hole 5 is higher than the height H1 of the burring 8 of the dummy tube insertion hole 6. The burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 has the joint between the burring 8 and the flat tube 32 formed near the top 8a of the burring 8, which increases the distance from the bottom surface 10 of the header plate 1 to the joint with the flat tube 32, and the stress generated at the joint with the header plate 1 due to thermal deformation of the flat tube 32 is dispersed throughout the burring 8. Therefore, by reducing the stress generated at the joint between the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 and the flat tube 32, durability against cold and heat can be improved. 4, when the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 is formed larger than the burring 8 of the dummy tube insertion hole 6, the radius of curvature of the burring 8 becomes larger, and the base of the burring 8 of the end tube insertion hole 5 moves closer to the adjacent dummy tube insertion hole 6. Therefore, when the dummy tube insertion hole 6 is formed to a normal burring height, it becomes difficult to ensure a sufficient inter-tube sealing surface 12 on the bottom surface 10 of the header plate 1 between it and the adjacent end tube insertion hole 5, and the seal ring 31 rides up on the burring 8 of the dummy tube insertion hole 6, making it impossible to expect a sufficient sealing effect around the partition section 22 of the tank body 21. Therefore, in the present invention, the height of the burring 8 of the dummy tube insertion hole 6 is formed to be lower than the height of the burring 8 of the end tube insertion hole 5 whose radius of curvature is adjacent to the dummy tube insertion hole 6, and by moving the rising position of the burring 8 closer to the dummy tube insertion hole 6, it is possible to ensure a sufficient inter-tube sealing surface 12 that can exert the effect of the seal ring 31 around the partition section 22 of the tank main body 21. The invention described in claim 2 is such that, in the above configuration, the ratio of the height H1 of the burring 8 of the dummy tube insertion hole 6 to the height H2 of the burring 8 of the end tube insertion hole 5 is H2 / H1≧1.5. As a result, the higher the height H2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, the less stress is applied to the joint between the flat tube 32 and the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6; and if the height H2 of the burring 8 of the dummy tube insertion hole 6 is made 1.5 times or more the height H1 of the burring 8, the distance from the bottom surface 10 of the header plate 1 to the joint of the flat tube 32 becomes even longer, thereby improving the stress reduction effect. [Brief explanation of the drawings]

[0007] FIG. 1 is a plan view and a cross-sectional view of a main part of a header plate 1 used in the header plate structure of the present invention. FIG. 2A is a plan view of a main part showing the header plate structure of the present invention, and FIG. 2B is an enlarged cross-sectional view taken along the line BB in FIG. 2A. Figure 3 shows cross-sectional views of IIIA-IIIA (A), IIIB-IIIB (B), IIIC-IIIC (C), and IIID-IIID (D) of Figure 2(A). FIG. 4 is an explanatory diagram showing a comparative example of the header plate structure of the present invention. FIG. 5 is a front view of a heat exchanger having a tank with a conventional header plate structure. 6A is a view of a main part taken along the line VI-VI in FIG. 5 and a cross-sectional view taken along the line BB in FIG. 6A. FIG. 7 is a cross-sectional view taken along the line VII-VII in FIG. 6(A). DETAILED DESCRIPTION OF THE INVENTION

[0008] Next, an embodiment of the present invention will be described with reference to the drawings. This heat exchanger is suitable for use in, for example, a radiator for cooling engine coolant. The tank of this heat exchanger is composed of a tank body 21 and a header plate 1. In this embodiment, the tank body 21 is made of synthetic resin and is formed in a box shape with an opening on the side connected to the header plate 1. A bottom is formed opposite the opening. A small flange 25 that bulges outward from the tank body 21 is formed on the edge of the opening. Then, for example, a pair of partitions 22 are arranged facing each other inside the tank body 21, spaced apart by approximately the width of one flat tube 32 in the short direction. As shown in Fig. 2(B) , the partitions 22 are formed at a central position in the longitudinal direction of the tank body 21, extending from the bottom of the tank body 21 toward the bottom surface 10 of the header plate 1. The ends of the partitions 22 are connected to the bottom surface 10 of the header plate 1 via annular seal rings 31, respectively. The interior of the tank body 21 is divided by a pair of partitions 22, and a first tank portion 23 and a second tank portion 24 are formed on either side of the pair of partitions 22. The header plate 1 is formed in an elongated rectangular shape in plan view. As shown in Figure 1(A) , a plurality of flat tube insertion holes 4 are formed in the bottom surface 10 of the header plate 1, each of which has a pair of opposing short sides 2 and a pair of long sides 3 connecting the short sides 2. The short sides 2 of the tube insertion holes 4 are positioned in the width direction of the header plate 1, and the tube insertion holes 4 are spaced apart from one another in the longitudinal direction of the header plate 1. This header plate 1 has a dummy tube insertion hole 6 (consisting of a pair of short side portions 2 and a pair of long side portions 3, similar to the tube insertion hole 4) formed in the middle position of the header plate 1 in the longitudinal direction, specifically, at a position corresponding to the position between a pair of partition portions 22 formed in the tank body 21. On either side of the dummy tube insertion hole 6, end tube insertion holes 5 (consisting of a pair of short side portions 2 and a pair of long side portions 3, similar to the tube insertion hole 4) and the tube insertion hole 4 are arranged in parallel in this order. The inner circumferences of the tube insertion holes 4, the end tube insertion holes 5, and the dummy tube insertion holes 6 are the same. Burrings 8 that protrude toward the inside of the tank body 21 are formed on the edges of the insertion holes 4, 5, and 6. The burrings 8 have a smoothly curved surface connecting their top 8a and base 8b. The inside of the burring 8 near the top 8a has a joining surface 9 that is formed into a flat surface to facilitate joining with the flat tube 32. As shown in FIG. 1(B), an outer peripheral wall is formed on the outer periphery of the header plate 1, rising toward the tank body 21, and a claw 13 for crimping is formed at the tip of the wall. 2(B), a raised portion 14 that rises toward the inside of the tank body 21 is formed on the bottom surface 10 formed in the tube insertion hole 4. The bottom surface 10 of the raised portion 14 is located at a higher position than the bottom surfaces 10 formed in the dummy tube insertion hole 6 and the end tube insertion hole 5. 1 and 3(D), a groove 11 is formed between the outer peripheral edge of the bottom surface 10 of this raised portion 14 and the outer peripheral wall of the header plate 1. The rigidity of the bottom 10 region of the raised portion 14 is higher than the rigidity of the bottoms 10 formed in the dummy tube insertion holes 6 and the end tube insertion holes 5. In this heat exchanger, a core is formed by arranging a large number of flat tubes 32 in parallel. The ends of the flat tubes 32 are inserted into the insertion holes 4, 5, and 6, and the flat tubes 32 are brazed and fixed to the joint surfaces 9 of the burrings 8 of the insertion holes 4, 5, and 6. Corrugated fins 33 can be arranged between the flat tubes 32, as shown in FIG. 2(B). As shown in Figure 2(A), a seal ring 31 is placed in the groove 11 of the header plate 1 and on the inter-tube seal 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. Then, the claws 13 of the header plate 1 are crimped onto 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 FIG. 2(B), the distal end of each of the pair of partitions 22 abuts against the seal ring 31 at the position of the inter-tube seal surface 12 . The core is divided on both sides of the dummy tube insertion hole 6 in the longitudinal direction by the dummy tube insertion hole 6, a pair of partitions 22 in the tank body 21, and the flat tube 32 inserted into the dummy tube insertion hole 6. A first core 34 is disposed on the first tank portion 23 side, and a second core 35 is disposed on the second tank portion 24 side, and different heat transfer media can be circulated through these cores 34, 35. As an example, engine coolant can be circulated through the first core 34, and accessory coolant can be circulated through the second core 35. In the above-described heat exchanger, if there is a temperature difference between the heat media flowing into the cores 34, 35, thermal distortion occurs between the cores 34, 35, and thermal stress occurs between the cores 34, 35 every time the heat exchanger is operated. In particular, thermal stress is likely to occur in the flat tubes 32 located near the partition 22 of the tank body 21, which is the boundary between the cores 34, 35. In the area of ​​the bottom 10 formed in the dummy tube insertion hole 6 and the end tube insertion hole 5, the ridges 14 are not formed to weaken the rigidity of the peripheral edges of these insertion holes 5, 6 relative to the rigidity of the rest of the hole. This absorbs stress generated in the flat tubes 32 inserted into the dummy tube insertion holes 6 and end tube insertion holes 5 located near the partition 22 of the tank body 21. The greater the number of end tube insertion holes 5, the more pronounced this effect becomes. In this example, three end tube insertion holes 5 are formed adjacent to each side of the dummy tube insertion hole 6. This embodiment has a structure for more effectively reducing the thermal stress occurring in the vicinity of the partition portion 22. On the long side 3 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, a burring 8 having a height H2 from the base 8b of the burring 8 to the top 8a of the burring 8 is formed. At the long side portion 3 of the dummy tube insertion hole 6, a burring 8 having a height H1 from the bottom surface 10 of the header plate 1 to the top portion 8a of the burring 8 is formed. As shown in FIG. 1(B), the height H2 of the burring 8 of the end tube insertion hole 5 is formed to be higher than the height H1 of the burring 8 of the dummy tube insertion hole 6. As shown in Figure 1(B), the end tube insertion holes 5 that are not adjacent to the dummy tube insertion holes 6 can have burring 8 formed on their long sides 3, with the burring 8 having a height H3 from the bottom surface 10 of the header plate 1 to the top 8a of the burring 8. The height H3 should be equal to or less than the height H2, but greater than the height H1. The thermal stress acting on the flat tube 32 of the end tube insertion hole 5 that is not adjacent to the dummy tube insertion hole 6 is smaller than the thermal stress acting on the flat tube 32 of the end tube insertion hole 5 that is adjacent to the dummy tube insertion hole 6, so a large height is not required. The burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 has its joint surface 9 formed near the top 8a of the burring 8, and the distance from the base 8b of the burring to the joint surface 9 with the flat tube 32 is long. In other words, the radius of curvature R2 of the curved surface from the base 8b to the top 8a of the burring 8 of that end tube insertion hole 5 is large. Therefore, stress generated at the joint with the header plate 1 due to thermal deformation of the flat tube 32 is dispersed over the entire curved surface of that burring 8. Therefore, by reducing the stress generated at the joint between the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 and the flat tube 32, durability against cold and heat can be improved. Figure 4 shows the problems caused by the reduction in the sealing surface when the height H1 of the burring 8 of the dummy tube insertion hole 6 is approximately half the height H2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, that is, is formed to be approximately the same as the height H3 of the burring 8 of the end tube insertion hole 5 that is not adjacent to the dummy tube insertion hole 6 in Figure 1(B) (a curvature radius R3 that is approximately half the curvature radius R2 of the burring 8). In this case, as shown in Figure 4, the base 8b of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 will be closer to the adjacent dummy tube insertion hole 6. Therefore, when the height H1 of the dummy tube insertion hole 6 is set to be approximately the same as the burring height H3, the width W2 of the inter-tube seal surface 12 will be narrower, making it difficult to ensure a sufficient inter-tube seal surface 12. In other words, as shown in Figure 4, the seal ring 31 will ride up onto the burring 8 of the dummy tube insertion hole 6, and a sufficient seal around the partition 22 of the tank body 21 will not be achieved. 1(B) and 2(B), the height H1 of the burring 8 of the dummy tube insertion hole 6 is formed lower than the height H2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, and the radius of curvature R1 of the burring 8 is made smaller than the radius of curvature R2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, thereby moving the position of the base 8b from which the burring 8 rises closer to the dummy tube insertion hole 6 and widening the width W1 of the inter-tube seal surface 12. This makes it possible to ensure an inter-tube seal surface 12 sufficient to demonstrate the effect of the seal ring 31 around the periphery of the partition 22 of the tank body 21. The ratio of the height H1 of the burring 8 of the dummy tube insertion hole 6 to the height H2 of the burring 8 of the end tube insertion hole 5 is preferably in the range of H2 / H1≧1.5. The higher the height H2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6, the more the stress applied to the joint between the flat tube 32 and the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 can be reduced. Specifically, if the height H2 of the burring 8 of the end tube insertion hole 5 adjacent to the dummy tube insertion hole 6 is set to be 1.5 times or more the height H1 of the burring 8 of the dummy tube insertion hole 6, the distance from the base 8b of the burring 8 to the joint surface 9 of the flat tube 32 becomes longer, thereby improving the stress reduction effect. The height of the short side connecting the long sides of the dummy tube insertion hole 6 and the end tube insertion hole 5 is preferably the same as or lower than the height of the long sides of the dummy tube insertion hole 6 and the end tube insertion hole 5. [Explanation of symbols]

[0009] 1 Header Plate 2 Short side 3 Long side 4 Tube insertion hole 5 End tube insertion hole 6 Dummy tube insertion hole 8 Barring 8a top 8b base 9 Joint surface 10 Bottom 11 Groove 12 Tube-to-tube sealing surface 13 Claw 14 Ridge 21 Tank body 22 Partition 23 First Tank Section 24 Second Tank Section 25 Small flange 31 Seal ring 32 Flat tube 33 Corrugated fin 34 First Core 35 Second Core R1, R2, R3 Burring curvature radius H1, H2, H3 Burring height W1 width W2 width

Claims

1. a flat, elongated header plate (1) having a pair of opposing short side portions (2) and a pair of long side portions (3) connecting the short side portions (2) and having a large number of tube insertion holes (4) formed in a bottom surface (10); a tank body (21) that is fixed to the header plate (1) by crimping via a seal ring (31); a flat tube (32) whose end is inserted into the header plate (1) and whose inserted portion is fixed by brazing to form a core; Equipped with The short sides (2) of the numerous tube insertion holes (4) are positioned in the width direction of the header plate (1), and the tube insertion holes (4) are spaced apart from one another in the longitudinal direction of the header plate (1), The tank body (21) has a pair of partitions (22) that divide the tank body (21) into a plurality of sections in the longitudinal direction, and among the tube insertion holes (4), those arranged between the partitions (22) are formed as dummy tube insertion holes (6), and a core is divided at the positions of the dummy tube insertion holes (6). In this header plate structure for a heat exchanger, The tube insertion holes (4) arranged adjacent to both sides of the dummy tube insertion hole (6) are formed as end tube insertion holes (5), A flat tube (32) is inserted into each of the tube insertion holes (4, 5, 6), a burring (8) is formed on the hole edge of each of the tube insertion holes (4, 5, 6), and the flat tube (32) is joined to the inner surface of each of the tube insertion holes (4, 5, 6) near the top (8a) of the burring (8). A burring (8) having a height H1 is formed on the long side (3) of the dummy tube insertion hole (6), A burring (8) having a height H2 is formed on the long side (3) of the end tube insertion hole (5) adjacent to the dummy tube insertion hole (6), The height H2 of the burring (8) of the end tube insertion hole (5) is formed higher than the height H1 of the burring (8) of the dummy tube insertion hole (6), A header plate structure for a heat exchanger, characterized in that the radius of curvature R1 of the burring (8) of the dummy tube insertion hole (6) is smaller than the radius of curvature R2 of the burring (8) of the end tube insertion hole (5).

2. 2. The header plate structure of claim 1, A header plate structure for a heat exchanger in which the ratio of the height H1 of the burring (8) of the dummy tube insertion hole (6) to the height H2 of the burring (8) of the end tube insertion hole (5) is H2 / H1≧1.5.

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