EP1890102B1 - Domed header plate for the tank of a heat exchanger - Google Patents

Description

The invention relates to a bottom part for a collecting box of a heat exchanger, e.g. a cooler, in particular oil cooler, with the other features in the preamble of claim 1.

In the EP 0 526 687 A1 an oil cooler is described in which the bottom part, also referred to as tube plate, for a collection box of this oil cooler consists of an at least partially flat flat part, which is designed approximately U-shaped in cross section. On this flat part, a U-shaped in cross-section cover part is fastened such that it is received with its two-sided legs between side walls of the bottom part, wherein in this area a pressure-resistant connection between the bottom part and the lid part. The bottom part contains openings for receiving einzusteckender pipes, which are in this case formed as flat tubes. In adaptation to the openings are approximately slit-shaped. The flat part has at least one rounded region, namely in such a way that the flat central region merges on both sides via rounded side regions into the two side walls of the bottom part. The slit-shaped openings for receiving and securing einzusteckender flat tubes extending in the transverse direction over the central region. The Tubes are juxtaposed to form spaces therebetween in which cooling fins are placed which enhance the heat exchange between the tubes and the medium to be cooled which flows through the tubes. The tubes are pressure-tight in the openings of the bottom part, eg by soldering. If the collecting box is acted upon by a medium to be cooled, which flows through the tubes and can reach a second collecting box, the bottom part is pressurized, whereby the bottom part can deform such that it is bent in the direction of the tubes. Accordingly, the connections between the bottom part and the tubes are under heavy mechanical stress. These high mechanical loads can lead to damage, in particular leaks in the joints, and affect the life of such a designed heat exchanger.

It is known a perforated plate for a tube heat exchanger ( DE 31 21 226 A1 ), in which the plate should generally have a curved or bulged or bent shape. This is to be achieved in that, instead of such a perforated plate whose center region is approximately at the same height as the ends thereof, inclined surfaces adjoin the middle region on both sides, which project beyond the plane of the central region. The middle region is connected via these inclined surfaces with U-shaped bent edges at its ends. The middle area is essentially flat. It is also mentioned here that the perforated plate has a sag which progressively increases from its edges to the middle region. In this case, the plate on the side of the bundle of tubes, ie on the opposite side of the water tank, bent. Hereby, a curvature is addressed about an axis extending in the longitudinal direction and parallel to the longitudinal extent of the perforated plate. Also in another known heat exchanger ( US-A-4,207,944 ) is the one part of a collecting tank, namely its bottom part, about a longitudinal axis curved approximately semicylindrical. Also from DE 40 04 949 A1 and JP 2005308366 A is a collection box for a heat exchanger known, the bottom part is curved about a longitudinal axis and approximately parallel to the longitudinal course of the collecting tank axis. From the GB-A-1 016 251 For example, a heat exchanger with an approximately spherical collecting box is known in which the bottom part and the cover part of the collecting box are formed as part of a ball in order to better withstand the high internal pressure in the collecting box. From the EP-A-0 198 581 is a heat exchanger with cylindrical tube header boxes known. The cylinder tube has slots on the side facing the tubes, into which flat tubes are inserted. In each case between two slots with inserted flat tubes located surface area of the collection box tube is formed as a convex curved dome. In a collecting box, which consists of lid and bottom part, the individual areas of the bottom part, which are located between slot openings for insertion of the tubes, designed as a convex curved to the tubes dome.

The invention has for its object to provide a bottom part for a header of a heat exchanger, e.g. for an oil cooler, which allows an increased strength of the flat part itself and also the connections between the flat part and pipes to be fastened thereto.

The object is achieved in a bottom part for a collecting box of a heat exchanger of the type mentioned according to the invention in that the flat part has a biaxially curved central part, which is about a longitudinal first axis and at the same time about a transverse, in particular approximately at right angles to the first Axis extending second axis is curved. It may be advantageous if the central part is curved in accordance with approximately a spherical cap. With such a biaxial, in particular approximately spherical section-shaped, curvature of the central part of a subsequent deformation of the flat part is already taken into account by pressure load; because the bottom part is connected to form a header box with a lid part and is the collection box with a medium under pressure Normally, a deformation of the flat part is to be expected under this medium pressure. Such a deformation under pressure tends at least in sections to a ball. Due to the corresponding curved central part is already taken into account by Vorwegkrümmung. As a result, no deformation of the flat part or at least a considerably reduced deformation of the same result under pressure. As a result, the connections between the flat part and attached pipes are mechanically relieved considerably. Due to the correspondingly curved central part can be reached, at least within limits, an almost ideal state in which under loading of the flat part otherwise prevailing bending stresses due to the biaxial, z. B. about spherical segment, curvature are converted into tensile stresses, whereby a greater strength of the flat part itself and the connections between this and the tubes is achieved. Since the strength of the flat part and the connections between this and the tubes from the exterior of the flat part towards the center decreases, especially in the central region of the flat part by the biaxial, z. B. approximately spherical segment-shaped, curved central part carried this bill and increased the strength of the flat part in the middle region accordingly. Due to this increased strength, it is possible to further reduce the cross-sectional thickness of the bottom part and / or the tubes and thus to achieve a weight and cost savings. The increased mechanical strength increases at the same time the life of a collecting box formed using the bottom part according to the invention and a correspondingly designed heat exchanger. This does not require additional expenditure with regard to the material, the number of components and the individual production stages. A further advantage is that reproducible and permanently tight connections between the bottom part and the individual tubes are possible with low manufacturing tolerances.

Other particular features of the invention and embodiments include the dependent claims.

Further details and advantages of the invention will become apparent from the following description.

The full text of the claims is not reproduced above solely to avoid unnecessary repetition, but instead referred to merely by reference to the claims on it, which, however, all of these claim characteristics have to be considered as explicit and essential to the invention at this point. Here are all mentioned in the preceding and following description features as well as the removable only from the drawings features further components of the invention, even if they are not particularly highlighted and in particular not mentioned in the claims.

Fig. 1

eine schematische perspektivische Ansicht eines Bodenteils für einen Sammelkasten eines Wärmeaustauschers,

Fig. 2

einen schematischen Längsschnitt des Bodenteils entlang der Linie II - II in Fig. 1,

Fig. 3

einen schematischen Querschnitt des Bodenteils entlang der Linie III - III in Fig. 2,

Fig. 4

eine schematische perspektivische Ansicht eines Teils eines Wärmeaustauschers mit einem Bodenteil entsprechend Fig. 1 bis 3.

The invention is explained in more detail with reference to an embodiment shown in the drawings. Show it:

Fig. 1

a schematic perspective view of a bottom part for a collecting box of a heat exchanger,

Fig. 2

a schematic longitudinal section of the bottom part along the line II - II in Fig. 1 .

Fig. 3

a schematic cross section of the bottom part along the line III - III in Fig. 2 .

Fig. 4

a schematic perspective view of a portion of a heat exchanger with a bottom part accordingly Fig. 1 to 3 ,

In the drawings, a bottom part 10 is shown, which is suitable for a collecting box of a heat exchanger 24, a part of which is schematically shown in FIG Fig. 4 is indicated. The heat exchanger 24 is suitable, for example, for an internal combustion engine, in particular a motor vehicle. It can serve as a cooler, in particular, for example, as an oil cooler, or instead be integrated as a condenser or as an evaporator and, for example, in a refrigeration cycle.

The bottom part 10 consists of an at least partially flat flat part 11 with an in Fig. 1 to 3 upwardly facing side 12, on the flat part 11 a not further shown cover part, for example by soldering, welding od. Like. Can be fastened. The flat portion 11 includes openings 13 which serve to receive einzusteckender tubes 14, as is made Fig. 4 is apparent. The flat part 11 has at least a rounded portion and is characterized in particular in that this flat part 11 has a curved central part 15, the biaxial, in particular corresponding to about a spherical cap, and thus z. B. spherical segment, curved. With such a curvature of the central part 15 a later deformation of the flat part 11 is already taken into account in advance; because the bottom part 10 is connected to form a collecting tank with a cover part and the collecting tank is subjected to a medium, so a deformation of the flat part 11 is to be expected under the medium pressure. Such a deformation under pressure tends at least in sections to a ball. Due to the approximately biaxial, in particular according to a spherical cap, curved central part 15 is borne by Vorwegkrümmung the bill with the result that under pressure loading no deformation of the flat part 11 or at least a significantly reduced deformation results. This leads to the fact that the connections between the inserted tubes 14 and the flat part 11 are mechanically relieved considerably. Due to the correspondingly curved central part 15, an ideal state can be achieved, at least within limits when the flat part 11 is loaded Bending stresses due to this curvature are converted into tensile stresses, whereby a greater strength of the flat part 11 itself and said connections between the flat part 11 and the tubes 14 is achieved. Since the strength of the flat part 11 and the connections between the flat part 11 and the tubes 14 decreases in the flat part 11 from outside to inside, especially in the central region of the flat part 11 is supported by the curved central part 15 and the strength of the flat part 11 in the middle Increased accordingly area.

The curved central part 15 is curved about a in the drawings only schematically indicated, longitudinally extending first axis 16 and at the same time about a transversely, in particular approximately at right angles, to the first axis 16 extending second axis 17. The flat part 11 has in the embodiment shown approximately rectangular contour with an approximately parallel to the first axis 16 extending longitudinal side 18 and a transverse thereto, in particular approximately at right angles thereto, extending transverse side 19. Accordingly, the curved central portion 15 is approximately rectangular. Accordingly, an approximately parallel to the longitudinal side 18 of the flat part 11 extending longitudinal axis forms the first axis 16 and thereby the axis of curvature for the transverse curvature of the central part 15, as is apparent from Fig. 1 and in particular Fig. 3 you can see. The radius of curvature for this transverse curvature is in Fig. 3 with r1, it being understood that the radius of curvature r1, relative to the other illustration in FIG Fig. 3 , not to scale.

An approximately parallel to the transverse side 19 of the flat part 11 extending transverse axis forms the second axis 17 and is the axis of curvature for the longitudinal curvature of the central part 15. The radius of curvature for this longitudinal curvature is in Fig. 2 schematically drawn with r2. It is understood that here too the size of the radius of curvature r2 in comparison to the representation of the flat part 11 is not to scale, since r2 in practice significantly larger than in the illustration according to FIG Fig. 2 is.

The radius of curvature r1 about the first axis 16 may be different from that of r2 about the second axis 17. Then results in the curved central portion 15 a deviating from a spherical portion biaxial curvature. Instead, the radius of curvature r1 about the first axis 16 may be the same as that r2 about the second axis. Then arises for the curvature of the central part 15 such as a spherical cap, d. H. a sphere section.

As in particular from Fig. 2 and 3 As can be seen, the transverse curvature of the curved central part 15 is approximately at the center of the longitudinal side 18 due to the longitudinal curvature largest, wherein the size of the curvature decreases from this center to both sides in the longitudinal direction.

The curved central part 15 is surrounded by a flat edge region 20 on the longitudinal side 18 and transverse side 19, which is not curved. This flat edge region 20 has at least on one side, in particular on the side 12, approximately planar attachment surfaces 21, which serve for the attachment of a cover part thereto.

At least most of the openings 13 used to receive tubes 14 are contained in the curved central part 15. Depending on the design, the arrangement may be such that e.g. only the outermost edge 22 of the two longitudinally outermost openings 13, which is adjacent to the flat local edge region 20, has no transverse curvature about the first axis 16.

The arrangement can also be made such that only individual regions of the flat part 11 have a biaxial curvature and other regions only a uniaxial curvature, in particular transverse curvature. Viewed in the longitudinal direction of the central part 15 can, for. B. at the beginning of a biaxial curved region are present, to which a uniaxially curved region, for. B. with transverse curvature, follows, then followed by a biaxially curved region.

In the embodiment shown, the tubes 14 are formed as flat tubes. In adaptation to the openings 13 are formed as a correspondingly adapted slots. The slot profile of these openings 13 is directed transversely to the longitudinal side 18 and the first axis 16 of the curved central part 15. At least some of these particular slot-shaped openings 13 are delimited by a passage 23, are created by the enlarged contact surfaces on the respective pipe 14 facing inside of the passage 23 and thus the strength and the guarantee of a tight connection between the flat part 11 and the individual tubes fourteenth is increased. With preference, the passages 23 point towards the side 12 of the flat part 11, to which the cover part (not shown) is to be fastened. Thus, the passages 23 then protrude when the collecting box is formed toward its interior. In another, not shown embodiment, the passages 23 but also to the other, the side 12 opposite side point. The passages 23 advantageously each have the same height, i. Instead, the passages 23, for example in the middle region of the central part 15, can also be higher than in the adjacent regions. The height of the passages 23 may be e.g. starting from the middle on both sides in the longitudinal direction 18.

The flat part 11 represents an integral component and is formed, for example, of aluminum. The production takes place for example by injection molding or deep drawing. The flat part 11 has a cross-sectional thickness of the order of about 0.8 to 6 mm.

The bottom part 10 is suitable for this and a cover part, not shown, which e.g. is placed on the mounting surfaces 21, a collecting box for a heat exchanger, e.g. for an oil cooler, to assemble. In this case, the cover part, not shown, on the flat, not curved edge portion 20 of the flat part 11, and in this case in particular on the flat mounting surfaces 21 of this, for. by welding, soldering od. Like., Pressure-tight. The cover part may also be formed of aluminum and preferably consists of a deep-drawn part.

Fig. 4 shows a portion of a heat exchanger 24 with at least one bottom part 10 to which a cover member, not shown, for attaching a header box is fastened, and with tubes 14 in the form of eg flat tubes, which are received in corresponding slit-shaped openings 13 in the bottom part 10 and pressure-tight by eg Soldering, welding od. Like. Are attached. Here, the fastening of the tubes 14 takes place at the openings 13 and the passages 23. The bottom part 10 and / or the collector to be formed therefrom have the features described above. It can be seen that the tubes 14 despite the biaxial, z. B. approximately spherical segment, curved central portion 15 all have the same length. The recorded in the openings 13 tubes 14 protrude with their ends, which protrude beyond the flat portion 11 and are directed towards the interior of a collecting box to be formed on different levels over the bottom part 10 and protrude accordingly different far into the interior of a manner to be formed Collection box into it. The tubes 14, which are located approximately in the region of the center of the central part 15, with their ends continue on the bottom part 10 than the remaining tubes 14, which connect in the longitudinal direction 18, starting from the center, on both sides. These adjoining on both sides of tubes 14 are end less than the bottom part 10 over than the tubes 14 in the region of the center. This also achieves an increase in strength; because the strength of the flat part 11 and the connections between this and the tubes 14 is greater in the region of the ends of the bottom part 10 as in the area of the middle. The strength decreases from the outside towards the middle. Since due to the same length of tubes 14 these now in the range about the center of the curved central portion 15 survive further than on both sides, viewed in the longitudinal direction 18, results in this central region a larger moment of resistance, whereby the strength is increased.

Due to the special design of the bottom part 10, a producible using such a bottom part 10 header tank for a heat exchanger and a heat exchanger 24, an increase in the strength of both the bottom part 10 and the connections between this and the tubes 14 is achieved. This makes it possible, if necessary, to further reduce the cross-sectional thickness of the individual components and thus to achieve weight and cost savings. Due to the increase in mechanical strength, the life of a collecting box formed using the described bottom portion 10 and a correspondingly designed heat exchanger 24 is increased, which does not require additional expenditure with regard to the material, the number of components and the individual production stages. A further advantage is that reproducible and permanently tight connections between the bottom part 10 and the tubes 14 are achieved with low manufacturing tolerances.

Claims (26)

1. Header plate for the tank of a heat exchanger, consisting of an at least partially planar flat part (11), to which a cover part can be fastened and which contains orifices (13) for the reception of tubes (14) to be plugged in, the flat part (11) having at least one rounded region, characterized in that the flat part (11) has a biaxially curved central part (15) which is curved about a longitudinally running first axis (16) and at the same time also about a second axis (17) running transversely, in particular approximately at right angles, to the first axis (16).
2. Header plate according to Claim 1, characterized in that the central part (15) is curved approximately correspondingly to a spherical cap.
3. Header plate according to Claim 1, characterized in that the radius of curvature (r1) about the first axis (16) is different from that (r2) about the second axis (17).
4. Header plate according to Claim 1, characterized in that the radius of curvature (r1) about the first axis (16) is the same as that (r2) about the second axis (17).
5. Header plate according to one of Claims 1 to 4, characterized in that at least most orifices (13) for receiving the tubes (14) are contained in the curved central part (15).
6. Header plate according to one of Claims 1 to 5, characterized in that the curved central part (15) is bordered by a planar non-curved marginal region (20).
7. Header plate according to Claim 6, characterized in that the planar marginal region (20) has, at least on one side (12), approximately planar fastening surfaces (21) for the fastening of a cover part thereto, for example by soldering, welding or the like.
8. Header plate according to one of Claims 1 to 7, characterized in that the flat part (11) has an approximately rectangular contour.
9. Header plate according to one of Claims 1 to 8, characterized in that the central part (15) is approximately rectangular.
10. Header plate according to one of Claims 1 to 9, characterized in that a longitudinal axis running approximately parallel to the longitudinal direction (18) of the flat part (11) forms the first axis (16) and the axis of curvature for the transverse curvature of the central part (15).
11. Header plate according to one of Claims 1 to 10, characterized in that a transverse axis running approximately parallel to the transverse direction (19) of the flat part (11) forms the second axis (17) and the axis of curvature for the longitudinal curvature of the central part (15).
12. Header plate according to one of Claims 1 to 11, characterized in that the transverse curvature of the curved central part (15) has the greatest curvature approximately in the region of the middle of the central part (15), and in that the size of the curvature decreases from the middle toward both sides in the longitudinal direction (18).
13. Header plate according to one of Claims 1 to 12, characterized in that individual regions of the flat part (11) have a biaxial curvature and/or other regions of this have a uniaxial curvature.
14. Header plate according to one of Claims 1 to 13, characterized in that the orifices (13) are designed, in adaptation to flat tubes (14) to be received, as correspondingly adapted slots, and in that the slot run is directed in each case transversely to the first axis (16) of the central part (15).
15. Header plate according to one of Claims 1 to 14, characterized in that at least some orifices (13) for receiving the tubes (14) are delimited by a rim (23).
16. Header plate according to Claim 15, characterized in that the rims (23) point towards that side (12) of the flat part (11) on which the cover part can be fastened or towards the opposite side.
17. Header plate according to Claim 15 or 16, characterized in that the height of the rims (23) is the same for all the rims (23).
18. Header plate according to one of Claims 1 to 17, characterized in that the flat part (11) is formed from aluminium.
19. Header plate according to one of Claims 1 to 18, characterized in that the flat part (11) has a cross-sectional thickness of the order of about 0.8 to 6 mm.
20. Tank for a heat exchanger, which is composed of a header plate (10) and of a cover part, characterized in that the header plate (10) has the features of one or more of the preceding claims.
21. Tank according to Claim 20, characterized in that the cover part is fastened, pressure-tight, to the planar non-curved marginal region (20) of the flat part (11), in particular to the planar fastening surfaces (21) of this, by welding, soldering or the like.
22. Tank according to Claim 20 or 21, characterized in that the rims (23) project towards the interior of the tank.
23. Tank according to one of Claims 20 to 22, characterized in that the cover part is formed from aluminium and preferably consists of a deep-drawn part.
24. Heat exchanger with at least one tank formed from a header plate (10) and cover part and with tubes (14) which are received and fashioned, pressure-tight, in orifices (13) in the header plate (10), the header plate (10) having the features of one or more of the preceding claims, characterized in that all the tubes (14) have the same length, and in that the tubes (14) received in the orifices (13) project, with their end directed towards the interior of the tank, beyond the header plate (10) and protrude into the tank interior to a different extent, the tubes (14) located in the region of the middle of the central part (15) projecting with their ends beyond the header plate (10) further than the tubes (14) following on both sides in the longitudinal direction.
25. Heat exchanger according to Claim 24, characterized in that the tubes (14) are designed as flat tubes.
26. Heat exchanger according to Claim 24, characterized in that the tubes (14) which follow on both sides from the middle of the central part (15) project with their ends beyond the header plate (10) to a lesser extent than the tubes (14) in the region of the middle.

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