EP2122290B1 - Heat exchanger for heat exchange between a first fluid and a second fluid - Google Patents

Description

The invention relates to a heat exchanger according to the preamble of claim 1. Such a heat exchanger is off US 5 092 397 known. The invention further relates to the use of such a heat exchanger as a charge air cooler for the direct or indirect cooling of charge air in a Ladeiuftzuführsystem for an internal combustion engine of a motor vehicle.

Heat exchangers are usually constructed, in particular in the case of the mobile application mentioned at the outset, as pipe-corrugated fin systems and, in particular in the case mentioned, are exposed to particularly high stochastic pressure and thermal cycling. The mentioned alternating stresses are decisive for the life of a heat exchanger. In particular, the thermal cycling is in a heat exchanger of the type mentioned above due to the resulting in the region of the tube ends particularly high mechanical stress amplitudes dominating the load. It has been found that within the block there is practically always an inhomogeneous temperature distribution with one of these directly associated inhomogeneous distribution of thermal expansions comes; the latter results in a distortion of the block. In this case, thermal expansion differences within the block can not only occur in a tube longitudinal direction, but generally also exist transversely thereto.

Basically it is, for example GB 169,855 , known to keep pipe ends in a passage in a heat exchanger. For this purpose revealed GB 169,855 a passage with a collar, which has a tooth-shaped contour formed by tongues at its end facing away from a bottom plate, in which a pipe end is held flexible and resilient. The tongues mentioned serve a local extension of the passage in order to take into account any sudden change in cross section of a pipe. Although this makes it possible to achieve a more flexible and flexible retention of pipes in the region of the passage - the latter, however, only leads to a general relief of a pipe-floor connection, without counteracting the concrete stresses in the area of the Rah-Baden connection.

Likewise are in DE 33 16 960 . US 4,150,556 and JP 11051592 A further possibilities of a passage with stepped, partially rectilinear collar contour for receiving a flat tube specified, which in turn can only achieve a flat mechanical improvement of the holder for a flat tube.

In DE 39 10 357 A1 a passage is disclosed, which has certain raised collar with an oval cross section for receiving a heat exchanger tube. To avoid cracks in the collar, especially in large ratios of the largest diameter to the smallest diameter thereof, the collar has a smaller height in the region of its small radii than in the region of its larger radii. As a result, the tearing of the collar should be largely eliminated, without thereby a significant reduction in performance of the heat exchanger also described there would have to be taken into account.

There, too, a substantially step-like, sectionally rectilinear collar contour is proposed, wherein a collar height also increases in transition areas between the smallest and the largest radius of the oval collar, in particular the Fig. 4 . 7 and 9 of the DE 39 10 357 A1 demonstrate. Such a heat exchanger is in particular in view of the problems occurring in an internal pressure change and / or temperature change due to the tensile and bending-causing stresses in need of improvement.

It would be desirable to improve the durability in a heat exchanger of the type mentioned.

At this point, the invention begins, whose object is to provide a heat exchanger in which the durability is improved.

The object is achieved by a heat exchanger with the features of claim 1.

In a heat exchanger according to the present invention, stresses in the region of the transition are reduced. Advantageously, a change in the distance value is continuous at least on the tube broadside and in the transition.

The stresses in the region of the transition can be reduced in particular by the fact that the distance value in the entire transition region between the pipe narrow side and the pipe broadside is minimal. In the in the DE 39 10 357 A1 proposed heat exchangers, the distance value is minimal at most in partial areas of the transition between the smallest and largest diameter of the oval passage opening. In the other transition areas, however, the distance value increases, so that the passages there have higher stiffness and accordingly induce stresses in the oval tubes that affect their durability.

The invention is based on the consideration that the bending deformations caused by expansion differences in the block are particularly strong in the area of a pipe-to-floor connection or a pipe-box connection and correspondingly lead to high mechanical stresses there. In this case, the invention has recognized that it is possible to determine the highest stresses along the pipe circumference, specifically in the region of the transition between the pipe narrow side and the pipe broad side. The invention is based on the recognition that a reduction, in particular minimization, of the stresses, especially in the region of the transition, leads to an increase in the service life of the heat exchanger. Accordingly, the concept of the invention provides that a distance value at least at a transition between the pipe narrow side and the pipe wide side is so less than a distance value at the tube broad side, that stresses in the region of the transition are reduced. Advantageously, a change in the distance value is continuous at least on the tube broad side and at the transition, so that stress concentrations are reduced or avoided by notch effects. A voltage occurring according to the knowledge of the invention, especially in the transition region is taken into account by the targeted reduction of the distance value at the transition according to the concept of the invention. In contrast to the approach described in the prior art of only a general relief of the entire pipe-floor connection region, the concept of the invention rather provides, in a controlled manner, for reducing the load of the transition as a region of particularly high tension. Above all, it is achieved by the concept of the invention that said high voltage is displaced into a region of low stress, for example in the side region of a pipe.

This advantageously results in a simpler geometry of a passage opening. Preferably, a floor or a box according to the concept of the invention can be even with a much reduced effort compared to the prior art produce and significantly improve the process reliability when Kassetieren of radiator networks. Overall, the durability of a heat exchanger is improved according to the concept of the invention. The advantages mentioned have resulted in particular in brazed heat exchangers. However, the concept of the invention has also been found to be effective in welded, glued or more advantageously joined heat exchangers.

Advantageous developments of the invention can be found in the dependent claims and specify in particular advantageous ways to realize the above-described concept of the invention within the scope of the task, as well as with regard to further advantages.

The concept has proven particularly advantageous in the case of a block in which the flow channels are accommodated by a chamber through which the second fluid can flow. Moreover, the concept according to the invention can be applied with regard to a box having a lid, the lid being fixed to the floor. The concept of the invention is also advantageous with respect to a floor integrally formed with the box. In such an integral, in particular one-piece, training of soil and cast a shaping of the unit in the course of production can be carried out particularly favorable by a hydroforming process.

According to the invention, in a case formed with a lid, a passage opening is formed as a passage, in particular as a passage with a collar, with a collar oriented towards the block. This type of soil has proven to be particularly easy to produce.

Preferably, the floor is substantially flat and / or said plane substantially indicates the floor level. In other words, it has the passage opening at least one, from one to the Rohrachsrichtung substantially perpendicular ground plane arched away and extending at a distance from said bottom plane boundary contour.

The distance value can be represented as required with regard to the expected stresses in the region of the transition according to the concept of the invention.

Preferably, the distance value, starting from the pipe broadside, for the first time in the transition between the narrow pipe side and the pipe broadside, less than in the region of the pipe broadside. Preferably, the distance value is also lower in the region of the pipe narrow side, in particular constant, than in the region of the pipe broadside. This leads to a particularly effective displacement of the stresses occurring at the transition in the region of a pipe broadside.

Within the scope of a particularly preferred development of the invention, it is provided that a contour curve of the limiting contour is a function of a circumferential dimension of the passage opening. As a dimension of a passage opening, in particular a length of a passage opening - corresponding to the pipe width side - and / or a width of a passage opening - corresponding to a pipe narrow side - serve. The concept of the invention provides that the polynomial function is formed in such a way that stresses in the region of the transition are reduced, preferably minimized. It has been found that a course curve in the form of a polynomial function of at least the second degree is advantageous. Thus, at the transition, a change in the distance value according to the concept of the invention may be continuous. Preferably, the degree of polynomial function is less than 5, that is, the polynomial function has no more than 4 extremes.

Concretely, a wide variety of limiting contours according to the concept of the invention can serve for the local reduction of the stresses in the region of the transition. Preferably, the distance value in the region of the pipe width side, preferably exactly, assumes a maximum value, preferably in the middle of the pipe broadside.

This results in a particularly large voltage displacement moment. In a further development not according to the invention, exactly one minimum value can be assumed by a distance value in the region of a pipe broadside, in particular in the middle of the pipe broadside. In other words, the distance value in this case has exactly two maxima on one side, in particular between the middle of the page and the transition to the pipe narrow side. In addition, the maximum value of the distance value can be determined according to the expected stress load. Preferably, a maximum value of the distance value in the range of 0.2 to 1.5 times the clear width of the passage opening - corresponding to the narrow side of the pipe. Maximum values in the range of 0.5 to 1.0 times the clear width are particularly advantageous here.

In addition, different variants of limiting contours can be combined at a through hole. According to a non-inventive embodiment, a passage opening on opposite sides on different variants of limiting contours. By way of example, a first non-inventive variant of a limiting contour can have exactly one maximum value of a distance value, while a second non-inventive variant of a limiting contour has precisely a minimum value of a distance value or a constant value of a distance value. Moreover, a first non-inventive variant of a limiting contour can have exactly one minimum value of a distance value and the second non-inventive variant of a limiting contour can have a constant value of a distance value. Such asymmetrical configurations of a passage opening have proven to be advantageous, although the expected stress load has an asymmetry.

For example, it has been found that the concept of the invention is particularly effective for corner tubes and / or for tubes arranged in an edge area of a block.

The invention has proven to be particularly advantageous in terms of heat exchangers as so-called pipe corrugated systems. For this purpose, a flow channel preferably has a heat-conducting element in the form of an inner rib attached to a channel inside, in particular soldered, and / or a heat-conducting element in the form of an outer rib attached to a channel outside, in particular soldered. The ribs are also called corrugated ribs. Preferably, the block may further comprise a flow guide, in particular a turbulence device.

The invention leads in a particularly preferred manner to a heat exchanger in the form of a direct or indirect charge air heat exchanger, in particular radiator or in the form of an exhaust gas heat exchanger, in particular radiator.

In a particularly preferred manner, the concept of the present invention can be used within the scope of the use of the heat exchanger of the type described above for an internal combustion engine of a motor vehicle, that is quite generally in the mobile sector.

An overall boundary contour of the passage opening or passage openings is preferably kink-free at least in the entire transitional area between a pipe narrow side and a pipe broadside. This avoids that stresses are increased by notch effects.

According to the invention, the overall boundary contour in the area of the tube broadside is substantially trapezoidal. Such passage openings are particularly easy to manufacture. In addition, corresponding heat exchangers have a high durability and good Kassetierbarkeit.

Flanks with a pitch angle in the range of 5 ° to 75 °, in particular in the range of 10 ° to 60 ° and especially in the range of 15 ° to 45 °, have proved to be particularly favorable. You make an optimal compromise between a sufficient support of the flow channels and a reduction of the voltages induced in these.

The distance value of the overall boundary contour to a plane substantially perpendicular to the tube axis direction along the circumference of the passage opening generally represents a function y (x) of a coordinate x in the circumferential direction of the passage opening.

Both for manufacturing and strength-theoretical reasons, it has proven to be particularly favorable if this function y (x) is defined in sections, wherein for each section k: $$\mathrm{y}\left(\mathrm{x}\right)={\underset{\mathrm{i}=\mathrm{0}}{\Sigma }}^{\mathrm{nk}}\left[{\mathrm{a}}_{\mathrm{ik}}•{\mathrm{x}}^{\mathrm{i}}+{\mathrm{b}}_{\mathrm{ik}}\sin \left({\mathrm{\omega }}_{\mathrm{ik}}•\mathrm{x}+{\mathrm{\phi }}_{\mathrm{ik}}\right)\right]\iff {\mathrm{x}}_{\mathrm{0}\mathrm{k}}\le \mathrm{x}\le {\mathrm{x}}_{\mathrm{1}\mathrm{k}}$$

In this case, Σ _{i = 0} ^nk denotes in the usual way the sum of i = 0 to nk and nk the order of the polynomial in the section k. Advantageously, these orders may differ in the different sections. Thus, straight or oblique sections which correspond to polynomials zero and first degree, respectively, alternate with sections of higher degree. Conversely, it has proved to be favorable that the polynomials each have at most the fifth degree, since otherwise the boundary contour becomes wavy.

Particularly advantageously, the functions defined in sections proceed continuously at the section boundaries, preferably one or more times continuously differentiable into one another, as is the case, for example, with cubic or B-splines.

x ⁱ denotes in the usual way the ite power of x, x _0k the coordinate at the beginning of a section k and x _1k the coordinate at the end of the section k. The coefficients a _ik , b _ik , ω _ik , φ _ik are constant and predetermined for each section k.

Here, the term E _{i = 0} ^nk b _ik sin (ω _ik • x + φ _ik ) is a Fourier series nk-th degree, can be approximated by the advantageous gentle, kink-free contours.

Of course, some or all of the coefficients of the polynomial or Fourier component in one or more sections may be identically zero, ie, in particular, the function may also be a pure polynomial function or pure Fourier series at least in sections.

Flat tubes of a heat exchanger according to the invention may for example have a substantially rectangular or oval cross-section. Similarly, for example, the narrow sides of the tube can be curved and the tube broad sides straight.

In the case of flat tubes with a substantially rectangular cross-section, a corner or a corner radius, in particular, where the narrow side of the tube and the broad side of the tube meet, is designated as the transition region between the narrow side of the tube and the broad side of the tube. In the case of curved pipe narrow and / or pipe broad sides, the transition region may in particular denote the region in which the pipe narrow side and pipe wide side approach one another perpendicular to their respective extent direction. Thus, in the case of a flat tube with a substantially oval cross section, essentially the area between the smallest and the largest diameter or, preferably, the area can be regarded as a transitional area in which the diameter is less than 80% of the largest and greater than 120% of the smallest diameter is.

While the invention has been found to be particularly useful for the use of the heat exchanger of the type described above and to be understood in that sense, and while the invention is described in detail below by way of examples from the mobile field, it will be understood that the present invention also is useful in the context of non-mobile applications or applications in the mobile field, which are not described specifically here are and which are outside of the areas explicitly mentioned here. For example, the presented concept also apply to a heat exchanger as a heater for the interior heating of a motor vehicle or as an oil cooler, in particular for cooling engine oil and / or gear oil, or as a refrigerant cooler or refrigerant condenser in a refrigerant circuit of an air conditioning system of a motor vehicle.

Embodiments of the invention will now be described below with reference to the drawing. This is not intended to represent the embodiments significantly, but the drawing, where appropriate for explanation, executed in a schematized and / or slightly distorted form. With regard to additions to the teachings directly recognizable from the drawing reference is made to the relevant prior art. It should be noted that various modifications and changes in form and details of an embodiment can be made without departing from the general idea of the invention. The features of the invention disclosed in the foregoing description, in the drawing and in the claims may be essential both individually and in combination for the development of the invention. The general idea of the invention is not limited to the exact form or details of the embodiment shown and described below. For the given design ranges, only all values within the specified limits are disclosed and claimed as limit values.

In an advantageous detail of the invention, an insertion bevel for simplified insertion of the flat tube is provided in the region of the boundary contour. Through such insertion bevels, which are basically known from passages according to the prior art, the insertion of the exchanger tube can be simplified and, in particular, damage to the limiting contour in the course of insertion can be avoided.

Further advantageously, a contact surface for surface soldering to the flat tube is provided in the region of the boundary contour. As a result, the soldering is improved overall and significantly reduced by defective solder joints rejects.

In a preferred embodiment of the invention, a draft having the boundary contour projects inwardly toward the box from the ground. Such orientation of the passage is particularly well suited to be combined in the sense of a simple production with an integrated or one-piece design of floor and box. To further simplify the production of the passages with inventive boundary contour, it is advantageously provided that the passage in one end region overlaps a bend of the bottom.

Fig. 1:

das Beispiel eines Bodens mit einem Durchzug bei einem Wärmetauscher gemäß dem Stand der Technik;

Fig. 2:

das Beispiel eines Bodens mit einem Durchzug nicht gemäß dem Konzept der Erfindung bei einer besonders bevorzugten Ausführungsform eines Wärmetauschers;

Fig. 3:

eine perspektivische Darstellung eines Kastens mit Boden und eingesetzten Flachrohren bei einem Wärmetauscher gemäß der in Fig. 2 gezeigten besonders bevorzugten Ausführungsform;

Fig. 4A:

das Beispiel einer Vergleichsberechnung einer Spannungsverteilung bei einem Durchzug gemäß Fig. 1 (Ansicht A) im Vergleich zu Fig. 2 (Ansicht B), wobei die Durchzüge gezeigt sind;

Fig. 4B:

das Beispiel von Fig. 4A ohne Durchzüge.

Fig. 5:

ein weiteres Beispiel eines Bodens mit einer abgewandelten Ausführung eines Durchzugs gemäß einer weiteren nicht erfindungsgemäßen Ausführungsform eines Wärmetauschers;

Fig. 6:

ein weiteres Beispiel eines Bodens mit einer abgewandelten Ausführung eines Durchzugs bei einer weiteren nicht erfindungsgemäßen Ausführungsform eines Wärmetauschers;

Fig. 7:

ein Beispiel eines gekrümmten Bodens bei einem Wärmetauscher gemäß einer alternativen nicht erfindungsgemäßen Ausführungsform der Erfindung;

Fig. 8:

ein weiteres Beispiel eines gekrümmten Bodens, welcher vorliegend integral mit einem Kasten bei einer alternativen nicht erfindungsgemäßen Ausführungsform eines Wärmetauschers gebildet ist;

Fig. 9:

ein weiteres Beispiel eines Bodens mit einer abgewandelten Ausführung eines Durchzugs gemäß einer weiteren bevorzugten Ausführungsform eines Wärmetauschers;

Fig. 10:

ein weiteres Beispiel eines Bodens gemäß einer weiteren Ausführungsform eines erfindungsgemäßen Wärmetauschers;

Fig. 11:

ein weiteres Beispiel eines Bodens gemäß einer weiteren Ausführungsform eines nicht erfindungsgemäßen Wärmetauschers; und

Fig. 12:

ein weiteres Beispiel eines Bodens gemäß einer weiteren Ausführungsform eines nicht erfindungsgemäßen Wärmetauschers.

For further understanding of the invention, preferred embodiments of the invention will now be explained with reference to the figures of the drawing. The drawing shows in:

Fig. 1:

the example of a floor with a passage in a heat exchanger according to the prior art;

Fig. 2:

the example of a floor with a passage not according to the concept of the invention in a particularly preferred embodiment of a heat exchanger;

3:

a perspective view of a box with bottom and inserted flat tubes in a heat exchanger according to the in Fig. 2 shown particularly preferred embodiment;

Fig. 4A:

the example of a comparison calculation of a stress distribution in a passage according to Fig. 1 (View A) compared to Fig. 2 (View B), with the passages shown;

4B:

the example of Fig. 4A without passages.

Fig. 5:

a further example of a floor with a modified embodiment of a passage in accordance with a further non-inventive embodiment of a heat exchanger;

Fig. 6:

a further example of a floor with a modified embodiment of a passage in a further non-inventive embodiment of a heat exchanger;

Fig. 7:

an example of a curved bottom in a heat exchanger according to an alternative non-inventive embodiment of the invention;

Fig. 8:

another example of a curved bottom, which is presently formed integrally with a box in an alternative non-inventive embodiment of a heat exchanger;

Fig. 9:

another example of a floor with a modified embodiment of a passage in accordance with another preferred embodiment of a heat exchanger;

Fig. 10:

another example of a floor according to another embodiment of a heat exchanger according to the invention;

Fig. 11:

another example of a floor according to another embodiment of a non-inventive heat exchanger; and

Fig. 12:

a further example of a floor according to another embodiment of a non-inventive heat exchanger.

A heat exchanger according to the concept of the invention is realized according to a preferred embodiment in the form of a charge air cooler for direct charge air cooling and serves for heat exchange between a charge air and a coolant, preferably air. For this purpose, the heat exchanger comprises a block comprising a radiator network for the separate heat exchanging guidance of the charge air and the coolant. For this purpose, the block has a number of flow channels through which charge air can flow, which additionally have a heat-conducting element in the form of an inner rib attached to a channel inside and a heat-conducting element in the form of an outer rib attached to a channel outside. Such usually consisting of an alternating superposition of pipes and heat-transmitting corrugated fins arrangement is also referred to as a radiator network. A box fluidly connected to the flow channels is associated with the block, and a bottom between the block and the box is provided with one or more through holes for passage of the flow channels between the block and the box.

A so-called passage with the radiator mesh oriented collar 17 '- as in Fig. 1 is shown - can be used especially for mobile applications such as the discussed intercooler for commercial vehicles. In principle, the known in the prior art improvement of the frictional connection by reducing the so-called. Bodenüberstandes - given as half the difference between tube depth t and depth T - are advantageously used to increase the internal pressure cycle resistance. One way to reduce the stresses in the region of the transition 27 'from the narrow pipe side 13 to the pipe broadside 15 can be achieved by the fact that at the transition 27' - as in Fig. 2 exemplified and based on Fig. 4A . Fig. 4B demonstrates - between the pipe narrow side 13 and the pipe broadside 15 a distance value such less than a distance value 25 at the tube broadside 15 is selected, that stresses ( Fig. 4A . Fig. 4B , View A) in the region of the transition 27 ', 27 are reduced (see in comparison Fig. 4A . Fig. 4B , View B).

Accordingly, an arrangement of a heat exchanger 10, not shown in FIG Fig. 3 shown in a perspective view. Fig. 3 shows the lid 5 of the box 3, wherein the lid 5 is fixed to the said bottom 1. The floor looks several in Fig. 2 closer passage openings 7 in front, which are provided for carrying out the flow channels between the not further illustrated block 9 and the box 3. As in Fig. 3 can be seen, flow channels in the form of flat tubes 11 are formed, wherein a flat tube 11 has a narrow side tube 13 and a pipe broadside 15. In the embodiment of the Fig. 2 and Fig. 3 is at the tube ends of the tubes 11 a bottom 1 with a plurality of through holes 7 each arranged in the form of a passage for receiving a tube 11, the block 9 with the both sides of the block 9 arranged collecting boxes 3 - of which only one is shown here - connect.

An alternative non-inventive embodiment of a tube plate is in Fig. 7 and a box is in Fig. 8 shown which will be described below.

In all embodiments, flat tubes are provided. In the present case, a flat tube 11 is formed as a rectangular tube. Moreover, in another embodiment, the cross-section of a tube may be varied. Thus, a cross section may be approximately rectangular, approximately oval or, for example, a rectangular cross section with a curved narrow side.

The in Fig. 2 in view A in perspective and in view B as a section again shown tube sheet 1 has the passage opening 7 in the form of a passage with a block 9 oriented collar 17. The collar 17 of the passage opening 7 is limited to the block 9 through a limiting contour 19, wherein the limiting contour 19 is curved away from a plane substantially perpendicular to the Rohrachsrichtung 21 level 23 and extends at a distance 25 to said plane 23. The distance 25 is in the in Fig. 2 illustrated embodiment of the present according to the passage opening length t in the middle of the pipe broad side 15 formed maximum distance. At the in Fig. 2 illustrated embodiment, the distance 25 thus assumes in the region of the tube broad side 15 exactly a maximum value as the maximum distance 25 at.

According to the concept of the invention, the distance value at the transition 27 between the narrow side 13 of the pipe and the broad side 15 of the pipe is so smaller than a distance value 25 on the pipe broad side 15 that stresses in the region of the transition 27 are reduced. As in Fig. 2 , View A, to better recognize, is also provided that on the tube broad side 15 and the transition 27, a change in the distance value 25 is continuous. In other words, the pipe run in the form of the collar present locally, starting from the transition 27, is continuously increased in such a way that the maximum stress at the transition 27 is minimized.

In the Fig. 2 illustrated embodiment has the in view B of Fig. 4A . Fig. 4B graphically, as a result of a finite element calculation for the lower tube section reproduced stress distribution result. Fig. 4A shows the result with bottom 1, 1 ', Fig. 4B without. The stress distribution in view B is the result of the contour curve of the limiting contour 19 designed to minimize the stress distribution, specifically the minimization of the stress in the region of the transition 27. Fig. 4A . Fig. 4B It can be seen clearly that the stresses in the region of the transition 27 - there around the curve of the boundary contour 19 around - outweigh, while they are comparatively small in the region of the maximum distance 25.

But above all, show Fig. 4A . Fig. 4B in view B, that by an interpretation of the curve of the boundary contour 19, the stress distribution in the Compared to a prior art embodiment in view A as shown in FIG Fig. 1 shown - can minimize. In the present case, this is achieved by a circular arc-like boundary contour 19, the - or the distance values - at the transition 27 continuously decreasing in the peripheral region along the narrow pipe side 13 - ie the region of the width of the through hole 7 - enters. In principle, a contour progression adapted to the specific stress distribution can be achieved by an overall circumferential change of the distance values, thereby minimizing the stress. Present is in Fig. 2 View A, that a distance along the width of the through hole 7 is also less than a distance value 25 on the tube broad side 15. Also this circumstance went into the calculations, as in Fig. 4A . Fig. 4B , View B, are shown.

In principle, it is possible, depending on the voltage field to be reduced, to provide a characteristic curve provided with any number of local maxima - with the proviso that the distance 25 between a contour curve of the limiting contour 19 and the ground plane 23 between the passages is also in the region of the transition 27 decreases continuously and is minimal. The boundary contours 19 represented in all figures in accordance with the concept of the invention can be formally described via their curve by one or more polynomials and / or Fourier series of the order nk, which are then defined in sections. For pure polynomial functions, (nk - 1) = m gives the number of local maxima in a section k: $$\mathrm{y}={\mathrm{a}}_{\mathrm{nk}}\mathrm{,}{\mathrm{x}}^{\mathrm{nk}}+{\mathrm{a}}_{\mathrm{nk}-\mathrm{1}}\mathrm{,}{\mathrm{x}}^{\mathrm{nk}-\mathrm{1}}...+{\mathrm{a}}_{\mathrm{1}}\mathrm{,}\mathrm{x}+\mathrm{b}\mathrm{,}$$

By a suitable choice of the coefficients a _i (with i = 1... Nk) and b, the desired position of the local maxima of the contour curve of the limiting contour 19 and its extent in the direction of the coordinate y can be determined depending on the stress field to be reduced. In an advantageous embodiment, the parameters mentioned are adapted such that the maximum distance 25 between the curve the distance contour 19 and the bottom plane 23 is in the range between 0.2 times to 1.5 times the clear width of the through hole 7. The width h is in Fig. 1 , View A, shown by way of example. With the help of such a specially adapted passage geometry is achieved that resulting from the change in temperature bending load - as in Fig. 4A . Fig. 4B shown - compared to an in Fig. 1 shown output geometry to larger proportions along the pipe broadside and a smaller proportion in the region of the highest loaded transitions 27 attacks. Thus, an overall uniform distribution of the load along the pipe circumference, ie the narrow pipe sides 13 and the pipe broad sides 15 is achieved.

It has been found that such a load-adapted design of the contour curve, especially with regard to different tube lengths (such as 64 mm or 50 mm), in particular in relation to a tube width (such as 8 mm), or cooler widths (depending on the number of tubes) effectively leads to a minimization of stresses in the region of the junction 27. Distance values above 1 mm or 2 mm are preferred.

Fig. 5 shows a not diversified embodiment according to the invention. In the in Fig. 5 In the embodiment shown, a through opening 7 on opposite sides 31, 33 has different variants of limiting contours 19A, 19B. A first variant of a limiting contour 19A corresponds to that in FIG Fig. 2 which exactly has a maximum value of a distance value 25. A second variant of a limiting contour 19B has a constant value of a distance value which lies below that of the distance value 25 and essentially corresponds to that of the narrow side 13 of the tube. At the transition 27 between the narrow pipe side 13 and the pipe broad side 15 of the distance value 25 is again such a smaller than a distance value on the pipe broadside 15 that stresses in the region of the transition 27 are reduced. In addition, a change in the distance value 25 on the tube broad side 15 and at the transition 27 is continuous.

Fig. 6 shows yet another varied not inventive embodiment of a bottom 1 with through hole 7, in which on opposite sides 31, 33 different variants of limiting contours 19C, 19D are provided. The first variant 19C is similar to the one in Fig. 2 However, has no continuous change of the distance value 25 at the junction 27 on. In contrast, the second variant of the limiting contour 19D has exactly one minimum value of a distance value, in the middle 35 of the tube broadside 15. In other words, the second variant of the limiting contour 19D has exactly two maxima 37A, 37B on one side 33, namely between the side center 35 and the transition 27. This also allows a significant reduction in the distribution of stress can be achieved. Both the in Fig. 5 as well as in Fig. 6 Thus, the embodiment shown has a one-sided design of a limiting contour 19A, 19D. In the Fig. 5 In another embodiment, the limiting contour 19B shown could also be replaced by a limiting contour 19D. In the Fig. 6 Contour contour 19C shown could also be replaced by a boundary contour 19a.

In the Fig. 1, Fig. 2 . Fig. 3 . Fig. 5 and Fig. 6 embodiments shown have a block 9 oriented towards passage with collar 17. For this reason, the draft is also referred to as an "upturned draft". Characteristic of the geometry of the passage is that a collar 17 "outwards", that is oriented towards the block 9 out. In contrast to the prior art ( Fig. 1 ) here is a curved boundary contour 19, 19A, 19B, 19C, 19D provided, ie a boundary contour, which does not extend parallel to the ground plane 23. Rather, a distance value 25 of the boundary contour 19 of the respective passage 17 from the bottom plane of the floor 1 is a function of a circumferential coordinate X, in the present case the longitudinal coordinate of the tube broadside 15. The curve of the limiting contour 19 is itself a function of the longitudinal coordinate X (FIG. Fig. 2 ). Characteristic of the passage 17 is further that the distance 25 of the collar 17 from the ground plane 23 between the passages in the region of the transition 27 between Rohrschmaiseite 13 and pipe broadside 15, ie in the region "Corner radii" of the passages continuously decreasing is the smallest and the maximum distance 25 along the broad side 15, in this case in the middle of the same, but in general somewhere along the broad side 15 - depending on the voltage field to be reduced - comes to rest. The middle of the broad side 15 is advantageous in the rule. In the embodiment of the Fig. 2 shown curve of the boundary contour 19 is characterized by a local maximum of the distance 25 from the ground plane 23 between the passages.

Fig. 7 shows an alternative embodiment not according to the invention, which provides a curved bottom 41 for a flat tube 11. Also in the in Fig. 7 In the case shown, the passage opening 7 has a curved from a to the Rohrachsrichtung 21 substantially perpendicular plane 23 away and at a distance from said plane 23 limiting contour 19E, 19F, which on opposite sides 31, 33 of a tube longitudinal side 15 identical as a contour of the overall circular formed tube bottom is present. In this particularly simple embodiment, therefore, eliminates the need for a collar 17 as in the in Fig. 2 . Fig. 3 . Fig. 5 and Fig. 6 to provide embodiments shown.

Fig. 8 shows a further particularly easy to manufacture non-inventive embodiment of a bottom 51, which in the present case is formed integrally with an air box 53 for a flat tube 11. In this embodiment, the need for an in Fig. 2 . Fig. 3 . Fig. 5, Fig. 6 To be soldered bottom 1 shown with a lid 5 of a box 3. Thus, with the in FIGS. 7 and 8 shown embodiments, increased durability of a charge air cooler and the elimination of additional costs causing additional measures, such as Eckrohrhülsen or reinforcing shoes are combined with a particularly reduced manufacturing costs.

Varyed embodiments as in Fig. 5 or Fig. 6 can therefore be provided only along a single pipe broadside 15 with a passage in the form of a collar. In particular, in Fig. 6 to see a passage in which the the boundary contour characteristic curve has more than a local maximum. Fig. 7 shows a, as explained, curved bottom 1, in which the previously described with respect to bending load advantageous curve in the ground itself is realized. In a basically similar way, the in Fig. 8 illustrated embodiment in which a box 53 and a bottom 51 form an integral component. All representations have in common that the curved curves can be described or approximated by a polynomial, as shown above, thereby ensuring that in the transition, a distance value continuously decreases and possibly assumes its lowest value. In particular for the in FIGS. 7 and 8 Solutions shown but also for the solutions shown in the other previous figures are clearly more complex curves than the circular arcs shown in the pictures conceivable. In relation to Fig. 1 running disadvantages are avoided.

Fig. 9 shows in Fig. 2 in a corresponding manner, a further varied embodiment of a bottom 1 with passage opening 7. The in Fig. 2 corresponding features are indicated by like reference numerals, so that will be discussed below only on the differences from this embodiment.

In the Fig. 9 shown embodiment has a Gesamtbegrenzungskontur 19, which, as in view B of Fig. 9 good to recognize, in the region of the tube broad side 15 is formed substantially trapezoidal.

In a middle section of the pipe broadside 15, therefore, the contour 19 runs essentially parallel to the plane 23 perpendicular to the pipe axis direction 21, so that a distance y (x) between the contour 19 and the boundary line in this section is given by a zero-degree polynomial of the coordinate x is described in the circumferential direction.

Before the transition regions 27, which are formed in the substantially rectangular cross-section of the through hole 7 through the small corner radii, in which Rohrbreit- and pipe narrow sides meet, the contour 19 is continuously differentiable in a sinusoidal course and runs out of this again continuously differentiable in a likewise substantially parallel to the plane 23 section, extending over a part of a pipe broadside, the Whole adjoining pipe narrow side and a part of the opposite other pipe broadside extends, so that the distance value y (x) in this entire section and thus in particular in the entire transition region between pipe narrow and pipe broadside is minimal. A continuously differentiable transition is understood to mean a transition between functions with the same pitch angle.

The flanks 100 of the essentially trapezoidal boundary contour 19 formed by the sinusoidal sections have on average a pitch angle σ of approximately 20 °. The distance 101 between the transition region 27 and the maximum value of the distance value 25 corresponds in the embodiment of the clear height h of the passage.

Fig. 10 shows a further embodiment, which is a modification of the embodiment Fig. 9 represents. In the lateral plan view shown here, the boundary contour 19 is not visible, but shown as a dashed line. The bordering in the lateral plan view of the passage and the boundary contour 19 slightly projecting edge 102 is not a limiting contour in the context of the invention, but an outer edge of an insertion bevel 103, which is provided for better usability of the exchanger tubes in the course of production of the heat exchanger. The insertion bevel 103 has the boundary contour 19 as the lower boundary in the direction of insertion of the tubes and forms a surface or phase inclined outwardly away from the tube, the outer boundary of which is the edge 102.

Such an insertion bevel 103, in the form shown or similar, may be useful in any of the above and below described embodiments of the present invention Be provided embodiments. As limiting contour 19 in the sense of the invention, the contact line of the passage is to be understood, with which the passage abuts against the pipe wall and is soldered. As a result of the course of this boundary contour 19 which touches the exchanger tube, the introduction of force from the exchanger tube into the ground, for example due to thermal expansion, is thus decisively influenced.

To ensure a good and in particular surface soldering closes in the present embodiment, a contact surface 104 of the limiting contour 19, as it is generally known from the design of conventional passages for heat exchangers. Such a contact surface 104 may be provided as required in each of the embodiments described above and below. A width of the contact surface 104 may advantageously vary over the course of the limiting contour 19, depending on which local forces are to be expected in the soldered state during operation at the respective position. Likewise, the width of the contact surface can be designed differently depending on the position, in order to ensure a reliable distribution of the solder during the soldering process even at critical points.

In contrast to the embodiment according to Fig. 9 is in Fig. 10 the reference plane 23 oriented perpendicular to the tube axis is positioned at the level of the end of the exchanger tube 15 inserted into the passage. By such a definition of the position of the reference plane 23 is also for oriented in the reverse direction passages (see, for example, the embodiments described below 11 and FIG. 12 ) ensures a correct definition of the distance value 25 in the sense of the invention.

The geometric course of the limiting contour 19 of the embodiment according to Fig. 10 corresponds to that of the embodiment described above Fig. 9 ,

Fig. 11 shows another example not according to the invention, in which a bottom 1 has a passage 105 projecting inwardly away from the block.

Starting from a substantially planar surface 106 of the base 1, the passage initially has an insertion bevel 103, which is particularly wide in order to simplify the introduction of the exchanger tubes, in particular in the regions of the short sides.

The end of the insertion bevel 103 is formed by a delimiting contour 19, which bears against the tube wall of an inserted exchanger tube. Analogous to the preceding embodiments, the delimiting contour has a region 27 in the vicinity of the transition from the long sides of the passage to the short sides, in which a distance value from a reference plane (not shown) becomes steadily monotonically smaller. The reference plane is perpendicular to the tube axis through the end of the tube inserted into the passage.

Similar to the embodiment according to Fig. 10 joins the boundary contour 19 a contact surface 104, which extends from the limiting contour 19 in the direction of the pipe end and allows an improved surface soldering of the passage with the pipe.

The in Fig. 11 The floor shown can be a section of an integrated, in particular one-piece design of floor and box. In particular, the integrated unit can be made of box and floor by means of a hydroforming process. In this case, a blank can be processed by means of hydroforming in a first step, after which the passages 105 are injected from the outside in a second step. Especially in such an embodiment of an integrated box and floor, it is appropriate in the interests of ease of manufacture that the passages project inwardly.

Fig. 12 shows a modification of the non-inventive embodiment Fig. 11 in which there is also an inwardly directed passage 105 with an insertion bevel 103, a shaped boundary contour 19 and a contact surface 104 adjoining the boundary contour 19.

In contrast to the embodiment according to Fig. 11 the passage is not arranged in a flat region of the bottom 1, but passes through two bends 107. The angled portions 107 of the floor cover with the inclined portions 27 of the boundary contour 19 and also correspond in angle to these areas 27. By providing such angled portions 107, therefore, the production of the passages with the course of the limiting contour 19 is simplified and reduces a rejection of production. In addition, the bends 107 support the rigidity and compressive strength of the soil.

As in the embodiment according to Fig. 11 is the bottom of the example after Fig. 12 particularly suitable to be formed as an integrated one-piece unit with a box and can be prepared in the same manner described above.

All of the shapes and courses described in the preceding exemplary embodiments, in particular the limiting contours 19, relate to an unsoldered state of the components.

Claims (28)

1. A heat exchanger, in particular a charge air cooler, for the heat exchange between a first fluid and a second fluid, with a block (9) for the separated and heat-exchanging guidance of the first and second fluid which has at least one flow channel through which the first fluid can flow;
   a box (3) which is fluidly connected to the flow channel and comprises a bottom (1) having a passage opening (7) for guiding the flow channel between the block (9) and the box (3);
   wherein the flow channel is in the form of a flat tube (11) with a narrow tube side (13) and a broad tube side (15),
   wherein the passage opening (7) has a total boundary contour (19) along the entire circumference of the passage opening (7) with a distance (25) to a plane (23) which is substantially perpendicular to the tube axis direction (21);
   characterised in that
   the passage opening is in the form of a passage with a collar (17) oriented towards the block (9) and the total boundary contour (19) is substantially trapezoidal in the area of the broad tube side (15) and
   before the transition areas (27), which are, with the substantially rectangular cross-section of the passage opening (7), formed by the small flanging radiuses, in which the broad and narrow tube sides meet, the contour (19) respectively transitions into a sinusoidal course in a continuously differentiable manner and from this course, in turn, ends, in a continuously differentiable manner, in a section which is substantially parallel to the plane (23).
2. The heat exchanger according to claim 1, characterised in that the total boundary contour (19) is free from bends at least in the total transition area (27) between the narrow tube side (13) and the broad tube side (15).
3. The heat exchanger according to claim 1 or 2, characterised in that the flanks of the substantially trapezoidal total boundary contour have a pitch angle (σ) in the range from 5° to 75°, preferably in the range from 10° to 60°, and especially preferably in the range from 15° to 45°.
4. The heat exchanger according to one of claims 1 to 3, characterised in that the distance value of the distance (25) of the total boundary contour (19) to the plane (23) which is substantially perpendicular to the tube axis direction (21) along the circumference of the passage opening (7) forms a function (y(x)) of a coordinate (x) in the circumferential direction of the passage opening (7), wherein this function (y(x)) is defined in sections and the following applies to every section (k): $$\mathrm{y}\left(\mathrm{x}\right)={\sum _{\mathrm{i}=\mathrm{0}}}^{\mathrm{nk}}\left[{\mathrm{a}}_{\mathrm{ik}}•{\mathrm{x}}^{\mathrm{i}}+{\mathrm{b}}_{\mathrm{ik}}\sin \left({\mathrm{\omega }}_{\mathrm{ik}}•\mathrm{x}+{\mathrm{\varphi }}_{\mathrm{ik}}\right)\right]\leftrightarrow {\mathrm{X}}_{\mathrm{0}\mathrm{k}}\le \mathrm{x}\le {\mathrm{x}}_{\mathrm{1}\mathrm{k}}$$

   

   wherein Σ_i=0 ^nk refers to the sum of i = 0 to nk, nk refers to the order of the polynominal in section k, xⁱ refers to the i-th power of x, x_0k refers to the coordinate at the beginning of section k, x_1k refers to the coordinate at the end of section k and a_ik, b_ik, ω_ik and ϕ_ik refer to constant coefficients which are predefined for every section (k).
5. The heat exchanger according to one of the preceding claims, characterised in that the block (9) has a chamber which receives the flow channel or channels and through which the second fluid can flow.
6. The heat exchanger according to one of the preceding claims, characterised in that the box (3) has a cover (5) and the cover (5) is fixed to the bottom (1).
7. The heat exchanger according to one of claims 1 to 5, characterised in that the bottom (1) is integral with the box (3).
8. The heat exchanger according to one of the preceding claims, characterised in that the bottom (1) is formed in a substantially flat manner and/or substantially extends in the plane (23) which is substantially perpendicular to the tube axis direction (21).
9. The heat exchanger according to one of the preceding claims, characterised in that the distance value, starting from the broad tube side (15), is for the first time smaller at the transition (27) between the narrow tube side (13) and the broad tube side (15) than in the region of the broad tube side (15).
10. The heat exchanger according to one of the preceding claims, characterised in that the distance value in the region of the narrow tube side is smaller, in particular constant, than in the region of the broad tube side (15).
11. The heat exchanger according to one of the preceding claims, characterised in that a trajectory course of the boundary contour (19) is a function of a circumferential dimension of the passage opening (7), in particular of a length of the passage opening (7) (broad tube side) and/or of a width of the passage opening (7) (narrow tube side), the trajectory course is in particular a polynomial function of a least the 2^nd degree.
12. The heat exchanger according to one of the preceding claims, characterised in that the distance value in the region of the broad tube side (11) becomes a maximum value.
13. The heat exchanger according to claim 12, characterised in that the distance value in the region of a broad tube side (11) becomes a maximum value at a distance (101) of a transition region between the narrow tube side and the broad tube side, wherein the distance (101) between the maximum value and the transition region is in the range of 0.2 to 2.5 times, in particular in the range of 0.25 to 2.0 times the clear width of the passage opening (7).
14. The heat exchanger according to one of the preceding claims, characterised in that the distance value in the region of a broad tube side (15) becomes exactly one maximum value, in particular in the centre of the broad tube side.
15. The heat exchanger according to one of the preceding claims, characterised in that a maximum value of the distance value is in the range of 0.2 to 1.5 times, in particular in the range of 0.5 to 1.0 times the clear width of the passage opening (7) (narrow tube side).
16. The heat exchanger according to one of the preceding claims, characterised in that the flat tube (11) is arranged as a tube in an edge region, in particular in an edge region of the block (9).
17. The heat exchanger according to one of the preceding claims, characterised in that a flow channel has a heat-conducting element in the form of an inner rib attached, in particular soldered, to the channel interior side, and/or a heat-conducting element in the form of an outer rib attached, in particular soldered, to the channel outer side.
18. The heat exchanger according to one of the preceding claims, characterised by a flow guidance arrangement, in particular a turbulence arrangement.
19. The heat exchanger according to one of the preceding claims in the form of a direct or an indirect charge air heat exchanger, in particular cooler.
20. The heat exchanger according to one of the preceding claims in the form of an exhaust gas heat exchanger, in particular cooler.
21. The heat exchanger according to one of claims 1 to 20, characterised in that the bottom (1) is curved at least in sections.
22. The heat exchanger according to one of the preceding claims, characterised in that the bottom (1) and the cover (5) form a component.
23. The heat exchanger according to claim 7, characterised in that the integral component consisting of the bottom and the box is formed by means of internal high pressure forming.
24. The heat exchanger according to one of the preceding claims, characterised in that in the region of the boundary contour (19), a lead-in chamfer (103) for easier insertion of the flat tube (11) is provided.
25. The heat exchanger according to one of the preceding claims, characterised in that in the region of the boundary contour (19), a contact surface (104) for the planar soldering to the flat tube (11) is provided.
26. The heat exchanger according to one of the preceding claims, characterised in that a passage (105) having the boundary contour (19) protrudes in the direction of the box starting from the bottom (1).
27. The heat exchanger according to claim 26, characterised in that the passage overlaps a bending (107) of the bottom in an end region.
28. Use of the heat exchanger according to one of the preceding claims for an internal combustion engine of a motor vehicle.

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