Device for transferring heat

Abstract

The invention relates to a device for transferring heat and especially an evaporator, especially for the air-conditioning system of a vehicle comprising at least one collecting tank comprising at least two collecting chambers.

Description

The invention relates to a device for transferring heat, and in particular to an evaporator, in particular for a vehicle air-conditioning system, having at least one header which includes at least two manifold chambers. Although the invention is described below with reference to the evaporator of a vehicle air-conditioning system, it should be noted that this intended use is not to be understood as constituting any restriction, but rather the heat exchanger according to the invention can also be used in other air-conditioning systems and other similar applications.

Devices of the abovementioned type for transferring heat are known from the prior art. DE 198 26 881 A1 has disclosed a heat exchanger which has a header formed from sheet metal by shaping a prepared metal plate. The header is divided in the longitudinal direction into two chambers, with the ends of two rows of flat tubes arranged one behind the other inserted into the base of the header and air that is to be cooled flowing through the flat tubes. The manifold chambers have side walls, the adjacent side walls of the two manifold chambers being oriented parallel to one another and bearing directly against one another, where they are soldered to one another and to the base in order to ensure that the header is leaktight.

DE 100 56 074 A1 has disclosed a heat exchanger in which the connection flanges are not, as is otherwise customary, arranged at the ends of the header, but rather on a longitudinal side portion, so that a simple structure without additional components can be realized. In a heat exchanger of this type too, the adjacent side walls of the two chambers are oriented surface-parallel to one another and are soldered to one another and to the base of the header.

One drawback of the heat exchangers which are known from the prior art is that it is necessary to maintain relatively tight manufacturing tolerances in order to keep scrap at a low level.

Therefore, the object of the present invention is to provide a heat exchanger in which greater manufacturing tolerances are possible.

The object of the present invention is achieved by claim 1.

Preferred refinements form the subject matter of the subclaims.

A heat exchanger in accordance with the present invention can be used in particular as an evaporator for a motor vehicle air conditioning system. The heat exchanger comprises at least one header having at least two manifold chambers, substantially each manifold chamber in each case being delimited substantially by a base means and a top part means. The top part means of a first manifold chamber comprises a first middle side wall, and the top part means of the second manifold chamber comprises a second middle side wall.

The first middle side wall is arranged adjacent to the second middle side wall at least over a section.

At least over part of a height of the manifold, a lateral distance between the first middle side wall and the second middle side wall increases with the height above the base means.

The heat exchanger according to the invention has numerous advantages.

On account of the fact that the header has at least two manifold chambers, which are arranged next to one another at least over a section, it is possible to provide a two-row evaporator, with the air which passes through the evaporator first of all passing by a first row of flat tubes and then passing by a second row of flat tubes.

Each manifold chamber is delimited by the base means and by a top part means; in this context, the term “top part means” is to be understood as meaning the boundary of the manifold chamber above the base means. The top part means may comprise one or two side walls and a covering wall or also one continuously curved (e.g. semicircular) wall or the like.

A gap which widens from the base means is achieved by virtue of the fact that the manifold chambers are arranged next to one another and the “middle” side walls, i.e. the right-hand side wall of the left-hand manifold chamber and the left-hand side wall of the right-hand manifold chamber, are at an increasing lateral distance starting from the base means.

This produces better flux transport and consequently better activation of the solder in the gap and therefore at the middle side walls and base means when the header is being soldered.

In the present context, the term “middle” side walls is to be understood as meaning the side walls lying next to one another (also “contact side walls”, since they are virtually or possibly even partially in contact with one another) of the first and second manifold chambers. Accordingly, in the case of a two-chamber manifold, the outer side walls are the side walls on the outer side, i.e. the side walls which do not have a manifold chamber arranged next to them. If a header has three manifold chambers, both side walls of the manifold chambers in the center are what are described as “middle” side walls, since they each have a further manifold chamber arranged adjacent to them.

A gap which is to narrow toward the base means, in particular during the warm-up phase, promotes the flux transport during soldering inward toward the base means. With conventional, i.e. parallel, side walls, the distance between the parallel walls has to be very accurately maintained, since the distance influences the capillary effect.

With a heat exchanger according to the invention, the manufacturing tolerances to be maintained are lower, since the gap distance changes continuously over the height and therefore even with relatively inaccurate manufacturing tolerances, a gap width which has a positive capillary effect is produced at a suitable distance.

As a result of the more favorable manufacturing tolerances, it is possible to reduce the costs of the production process, while at the same time achieving a lower scrap rate. Depending on the way in which the accuracy of the manufacturing tolerance and the costs of the production process are adapted to one another, it is possible to select a low scrap rate or a scrap rate which is slightly higher than the possible minimum, but with an overall reduction in the production costs on account of the more favorable manufacturing tolerances.

In a preferred refinement of the invention, the lateral distance between the first and second middle side walls or the contact side walls is substantially V-shaped. A distance profile which increases continuously and strictly monotonously is advantageous since this always results in a suitable lateral distance substantially irrespective of the manufacturing tolerances.

In a further preferred refinement of the invention, at least one stability means or a distribution means is arranged on at least one side wall. A stability means increases the stability. A distribution or stability means may be provided on a middle side wall or alternatively also on an outer side wall.

It is also possible for one or more distribution or stability means to be arranged both on one or more middle side walls and/or on one or more outer side walls. The distribution or stability means may be provided in the interior of the manifold chambers and/or in the space outside them or may extend inside and outside the manifold chambers.

It is preferable for a longitudinal direction of at least one distribution or stability means to be oriented substantially perpendicular to the base means, so that the distribution or stability means preferably extends approximately in a direction substantially perpendicular to the surface of the base means.

In a preferred refinement, at least one distribution or stability means is designed as a recess means and may, for example, be formed as a groove means or notch or the like.

In this case, it is possible for the recess means to be a recess in the outer surface of a side wall of a manifold chamber which, for example, extends from the base means to a predetermined height above the base means. The recess means may in this case, for example, be of V-shaped or U-shaped design, in which case the width of the U, i.e. the width between the limbs of the U, may be greater by a multiple than the depth of the U.

By way of example, ratios of recess width to recess height of from 1:10 to 100:1 are possible, with the range from approximately 1:5 to 80:1 being preferred. In the case of notch-shaped recess means, a ratio in the region of 1:1 tends to be preferred, whereas in particular in the case of groove-like recess means considerably greater values are also possible.

Recess means or stability means produced in particular, although not exclusively, by chipless production processes generally increase the stability in the lateral direction of the side walls and therefore of the manifold chambers as a whole.

Distribution means facilitate the distribution of the flux and of the soldering agent.

This also produces an improved manufacturing process, since the manufacturing tolerances can be reduced while retaining the same scrap rate or even achieving a lower scrap rate.

Recess means on the outer sides of the middle side walls or the contact walls are advantageous since they ensure that a capillary gap is formed between the side walls or limbs of the manifold chambers, which capillary gap, depending on the width of the recess means, may even be of large-area form. Capillary gaps of this type, i.e. both narrow and large-area capillary gaps, promote the flux transport during soldering, so that a reliable soldered join can be achieved between the individual side walls and also between the side walls and the base means.

In the case of typical flat tube evaporators for the air-conditioning systems of automobiles, the height of the recesses may be between approximately 0.05 and 0.4 mm, while the width may be in the range between 0.05 and 8 or 10 mm or even more. It should be pointed out at this point that these numerical details merely relate to one specific example. Both smaller and larger dimensions are possible with these flat tube evaporators and with other flat tube evaporators, as well as evaporators in general.

In a further preferred refinement of the invention, at least one distribution means or at least one stability means projects outward, in which case preferably at least one distribution or stability means projects outward from a side wall of at least one manifold chamber. It is particularly preferable for at least one stability means to project outward on one of the middle side walls or the contact side walls, so that the lateral distance (or gap) between the two middle side walls is reduced at the location of a stability means.

It is preferable for at least one distribution or stability means to be formed as a bead means, which is preferably produced by a chipless route.

It is particularly preferable for a plurality of distribution or stability means to be distributed, preferably at regular intervals, over at least one portion or even the entire length of at least one manifold chamber, in which case the stability means may be arranged alternately on the outwardly facing surfaces of the middle side wall of the first manifold chamber and the middle side wall of the second manifold chamber. It is also possible for all the stability means to be provided on just one middle side wall or on just one manifold chamber.

In a preferred refinement of the invention, the depth of a distribution or stability means increases at increasing distance from the base means. By way of example, the depth, i.e. the vertical distance from the outer dimension of the stability means to the side face, may be one third of the maximum depth in the vicinity of the base means. In the case of outwardly projecting stability means, this is the height with respect to the side wall, whereas in the case of recess means as stability means, what is meant is the depth of the recess means with respect to the side wall.

In a preferred refinement of the invention, a recess is provided in the base means in a contact region between the middle side walls and the base means, in which case this recess may be designed, for example, as a base bead, in order, for example, to form a guide for the ends of the side walls.

In a further preferred refinement of the invention, at least one flat tube has a lower wall thickness in the region of a flank than in a region of the rounding or of the radius.

This refinement is highly advantageous since as a result of the special tube geometry of the flat tube with the increased radius, it is possible to achieve a low flat tube weight combined with a high strength.

This results in a lighter tube and therefore a low overall weight. As a result, lower total costs can also be achieved.

The wall thickness of the flat tube is preferably 10% or 20% or more lower in the region of the flanks than in the region of the radius.

The ratio of the wall thicknesses in the radius to the wall thickness at the flank is preferably in a range from approximately 1.2 to 3 and particularly preferably in a range between approximately 1.4 and 2.

In one configuration of the invention, the wall thickness of the flat tube in the region of the flanks may be approximately 0.2 to 0.4, preferably 0.3 mm at at least one location. In particular in this configuration, the wall thickness of the flat tube in the radius region is then between 0.4 and 0.7 mm and preferably approximately 0.5 to 0.6 mm at at least one location.

The fact that the wall thickness is reduced in the region of the flanks overall saves a considerable part of the weight of the flat tubes.

In a preferred refinement of the invention, at least one top part means is produced as a single piece, so that the middle and outer side walls and the upper covering wall of the top part means form a single piece.

In a preferred refinement of the invention, at least one top part means or two top part means are produced integrally as a single piece with the base means. It is then possible, for a header which comprises two manifold means, to produce substantially the entire header as a single piece from a prepared metal plate, for example by bending.

To divide the header into at least two chamber means, it is possible for the header to be of single-part design, in such a manner that the side elements which adjoin the base element are curved in the direction of the base element and are ultimately joined to one another and to the base element.

For this purpose, it is necessary for the side elements to be permanently joined to one another and to the base element, for example by soldering. By way of example, it is known for the side elements to be designed in such a manner that they run substantially vertically on to the base element and can therefore be surface-soldered to one another and to the base element.

The base means can be prepared in such a manner that it has the desired dimensions or also the required openings or cutouts for joining to the side or top part means. Since the header can be made into its definitive shape even before final soldering, a high strength of the means results even before soldering.

In a preferred refinement of the invention, at least one connection opening for the heat transfer is arranged on a longitudinal side portion of the header, in which case it is also possible for a connection opening to be arranged at an end side of a header or for both connection openings to be provided at the end sides or on one or both of the longitudinal sides of the header.

In a preferred refinement of the invention, the header is connected to two rows of heat transfer tubes arranged one behind the other. It is also possible for three or even more rows of heat transfer tubes to be connected to the header. It is preferable to provide one manifold chamber for each row of heat transfer tubes, but it is also possible to provide one manifold chamber for in each case, for example, two (or three or more) rows of heat transfer tubes.

In a preferred refinement, at least one side wall is provided with at least one tab device or the like which is fitted into cutouts in the base means. The fitting point can in this case be jammed together. The jamming point can also be stamped in the guide bead after the header has been deformed. Jamming of the fitting point prior to soldering offers the advantage of secure joining of the parts which are to be soldered.

It is preferable for a closure cover to be arranged at at least one and preferably both ends of the manifold chambers.

Furthermore, it is preferable for there to be a guide bead for the partition wall, so that the partition wall substantially cannot become tilted, resulting in improved bearing of the partition wall against the header as a result of the U-shaped encapsulation. A U-shaped encapsulation or bead in the region of the bearing surfaces of the side walls or limbs also results in larger soldering surfaces.

The combination of a, for example, V-shaped gap between the inner side walls of the two manifold chambers and further distribution or stability means in the form of projecting beads or recesses provides the option of a wider range of tolerances, so that in one specific example the gap distance at the open end of the V-shaped gap can vary by up to 50%, allowing a possible fluctuation between 0.15 and 0.23 mm, while at the lower end at the base means it is between 0.05 and 0.11 mm.

The stability means ensure that there is always a sufficient capillary gap for flux transport, irrespective of manufacturing-related deviations in shape.

Gaps which are too large or too small in conventional heat exchangers prevent the flux transport in particular in the heat-up phase, which means that tighter manufacturing tolerances have to be observed or a higher scrap rate has to be accepted.

Further advantages and possible applications of the invention are described below with reference to the drawings, in which:

FIG. 1 shows a perspective view of a heat exchanger according to the invention in accordance with a first preferred embodiment;

FIG. 2 shows a partial view of the header from the exemplary embodiment shown in FIG. 1;

FIG. 3 shows a partial view of a top part of the header shown in FIG. 2;

FIG. 4 shows the header shown in FIG. 1 in section;

FIG. 5 shows detail A from FIG. 2;

FIG. 6 shows a diagrammatic side view of part of the header of the heat exchanger shown in FIG. 1;

FIG. 7 diagrammatically depicts a second exemplary embodiment of a header;

FIG. 8 shows a diagrammatic side view of a third embodiment of a header of a heat exchanger;

FIG. 9 shows part of a sectional view A-A through the header shown in FIG. 8;

FIG. 10 shows a flat tube according to the invention in section; and

FIG. 11 shows a further exemplary embodiment of a heat exchanger according to the invention in side view.

A first exemplary embodiment of the heat exchanger according to the invention, which is designed as an evaporator for a vehicle air-conditioning system, will now be explained with reference to FIGS. 1 to 7.

The heat exchanger which is illustrated in perspective in FIG. 1 comprises an upper header 2, a lower header 11 with heat transfer tubes 9 arranged between them.

The upper header 2 comprises a first manifold chamber 3 and a second manifold chamber 4 which is parallel to it, the end sides of which manifold chambers are closed off by covers 5. The inlet 6 and the outlet 7 for the cooling medium that is to be evaporated is provided on a longitudinal side 8 of the first header 3.

At this point, however, it should be noted that the inlet and outlet may be provided not only on a longitudinal side 8 of one or both manifold chamber(s) of the header 3, but rather it is also possible for the inlet to be provided on a longitudinal side of the first header and the outlet to be provided on a longitudinal side of the second header.

It is also possible for the inlet and outlet to be provided at the end sides of one or both manifold chambers, as illustrated in the exemplary embodiment shown in FIG. 11, in which inlet and outlet are provided at the end sides of the two manifold chambers of the header.

The detail illustrated on an enlarged scale in FIG. 2 illustrates the base 12 of the header 2 and a top part 13 of the first manifold chamber 3.

The top part 13 of the first manifold chamber 3, in the present exemplary embodiment, is produced as a single piece with the base 12 of the header. The second top part 23 may also be produced as a single piece with the base 12.

The top part 13 of the first manifold chamber 3 comprises an outer side wall 14, an upper wall 16 and a middle side wall 15, which in the present exemplary embodiment is arranged approximately in the center of the header 2.

Bending over a side edge region of the base 12 forms the top part 13 having the outer side wall 14, the middle side wall 15 and the upper side wall 16, with a gradual transition between the individual wall regions. The “middle” side wall 15, which lies in the center of the base 12, is in this case formed by the end of the single-piece component. As a result of the use of auxiliary bending units 100, 100′, such as preferably beads or stamp formations, the material can be bent more easily and in a more controlled way at the locations which are to be bent. In this case, it is expedient if the auxiliary bending element reduces the wall thickness, so that the bending operation can take place more easily at this point. According to the invention, the auxiliary bending element can be introduced into the wall from inside the header and/or outside the header.

FIG. 2 shows that the base means and the top part means are produced from a single part, with auxiliary bending elements 100, 100′, 101, 101′ being provided at least at locations at which the base means and the top part means and/or the top part means and a side wall (cf. FIG. 4) adjoin one another. The auxiliary bending elements in this context are regions of reduced wall thickness, such as preferably individual lines and/or points or a plurality of lines and/or points.

The wall thickness reduction produced by the auxiliary bending elements is preferably in the range from 10% to 50% compared to the normal wall thickness. It is particularly expedient if the reduction is in the range from 20% to 40% compared to the normal wall thickness.

As can be seen from FIG. 3, the end of the middle side wall 15 has tabs 18 which project beyond the end of the middle side wall 15 and, during manufacture, can be fitted into corresponding cutouts 19 in the base region of the header. There, the tabs 18 are preferably jammed to the base 12, so as to securely fix the top part 13 and the middle side wall 15 to the base element 12. This ensures that the individual elements are successfully and permanently soldered together, since it is impossible for any parts to move with respect to one another during the soldering operation. This is also illustrated on an enlarged scale in FIG. 5.

Tube receiving parts 17 for the flat tubes 9 that are to be connected are provided in the base 12 of the header 2.

Overflow openings 21, which allow the refrigerant to flow over from the first manifold chamber 3 to the second manifold chamber 4 or in the reverse direction, depending on the particular embodiment, are provided in each of the middle side walls 15 and 25 in an end region of the first manifold chamber 3 and the second manifold chamber 4.

FIG. 4 illustrates a side view, in section, of the header 2, with tabs 18 fitted into cutouts 19 and jammed in place there, in order to facilitate soldering, in the base 12 in the region of contact with the middle side walls 15 and 25. The header 2 has a total height 69.

FIG. 6 illustrates a diagrammatic side view, not to scale, of the contact region between the middle side wall 15 and the middle side wall 25 and the base 12 of the header 2. Whereas a lateral distance 33 is provided at the point of contact with the base 12, a lateral distance 32 between the middle side walls is present at a height 29 above the base 12.

In the exemplary embodiment, the distance 33 is provided to be 0.1 mm, and at a height 29 of approximately 10 mm the distance 32 is approximately 0.3 mm, so that the aperture angle between the middle walls 15 and 25 is approximately 10. The V-shaped gap 22 allows a reliable capillary effect during soldering.

At the height 29 above the base means 12, a bend 10 is provided in the first manifold chamber 3 and a bend 20 is provided in the second manifold chamber 4, as can also be seen in the not so diagrammatic drawing shown in FIG. 4. Whereas the outer side walls 14 and 24 merge into covering walls 16 and 26, respectively, without a discernible transition point, in the exemplary embodiment the middle side walls 15 and 25 are clearly delineated from the covering walls 16 and 26, respectively, at the bends 10 and 20.

FIG. 7 illustrates a further exemplary embodiment of a header 2, in which identical parts are provided with the same reference designations. This header 2 likewise comprises a first manifold chamber 3 and a second manifold chamber 4, which each comprise middle side walls 15 and 25, respectively.

In this exemplary embodiment, one bead 31 or a plurality of beads 31 are provided in the V-shaped gap 22, generally arranged at regular intervals over the length of the header 2.

The individual beads 31 may, for example, be provided only on the outer side of the middle side wall 25, but it is preferable for them to be provided alternately on the outer side of the middle wall 15 and of the middle wall 25. On account of manufacturing conditions, however, it is also possible for the beads to be provided only on an outer side of one middle side wall (15 or 25).

The external shape of the bead 31 is substantially also V-shaped, so that it has a lower depth, i.e. a shorter distance from the outer side of the wall, in the region of the base 12 than in the upper region at the distance 29 at the height of the bend 20. The dimensions of the bead 31 can be adapted to the gap 22 in such a manner that the depth in the base region is approximately 0.1 mm and the depth at the height 29 above the base 12 is approximately 0.3 mm. The height 59 of the bead can but does not have to coincide with the height 29 of the bends 10, 20.

However, other dimensions are also possible, and consequently these numerical details are to be understood merely as examples. In particular, it is possible for the dimensions of the bead to be a certain percentage smaller than the dimensions 32 or 33 which define the intended distance between the side walls 15 and 25. The beads then guarantee a minimum distance.

In addition to the exemplary embodiment shown in FIGS. 1 to 6, the exemplary embodiment shown in FIG. 7 also provides a recess 30 of a depth 34, which in the exemplary embodiment amounts to 0.1 mm, in the contact region between the side walls 15 and 25 and the base 12. The recess 30 facilitates production of the header 2, since the ends of the side walls 15 and 25 are guided into the recess 30, ensuring that they are held reliably in place, prior to the soldering operation.

The beads 31 produce large-area capillary gaps allowing a good distribution of the flux and of the soldering agent. Furthermore, the beads 31 perform the function of a spacer between the outer sides of the middle side walls 15 and 25. It is reliably ensured that the distance is not too short to ensure a reliable soldered join.

In the exemplary embodiment shown in FIGS. 8 and 9, stability means designed as grooves 35 are provided. The grooves 35 have a depth 36 which in the exemplary embodiment amounts to 0.1 mm. In a similar way to the exemplary embodiment having the beads 31 as shown in FIG. 7, so too in the exemplary embodiment having the groove-like recesses 35 as shown in FIGS. 8 and 9, the depth of the grooves may change with the distance from the base 12 of the header.

In this exemplary embodiment too, the surface profiling which is formed by the grooves 35 provides the top part(s) 13 and/or 23 of the two manifold chambers 3, 4 with stability.

The grooves 35 perform the function of distributing flux and soldering agent, so that reliable joining of the side walls 15 and 25 to the base 12 is possible.

As was already the case in the previous exemplary embodiment, a recess 30 is provided in the contact region between the middle side walls 15 and 25 and the base 12.

FIG. 9 shows a sectional view A-A from FIG. 8.

FIG. 9 reveals the groove-like recesses 35 in plan view. In this exemplary embodiment, the groove-like recesses 35 are arranged on both middle side walls 15 and 25.

In this exemplary embodiment, the grooves have been formed by compression of the material during the bending process for producing its shape, so that the recesses illustrated are produced on each of the outer sides of the middle side faces.

There are a plurality of recesses, which are in this case also at the same distance 61 from one another at the middle side walls. The recesses on the side wall 15 are laterally offset by an amount 62, which preferably corresponds to half the distance 61, with respect to the recesses on the side wall 25.

In the exemplary embodiment shown in FIGS. 8 and 9 too, the distance 33 between the side walls in the contact region between the side walls and the base is approximately one third of the distance at the height 29 of the bends 10 and 20.

FIG. 10 shows a flat tube 40 for a heat exchanger for one of the exemplary embodiments.

The flat tube has external dimensions perpendicular to the direction of flow of a refrigerant which equate to a length 41 of 30 mm and width 42 of 3 mm. However, other dimensions are also possible. The wall thickness has a dimension 44 of 0.55 mm in the region of the radius or the rounded sections 43, whereas a considerably lower wall thickness 45 of 0.3 mm is present in the region of the flanks 49.

The flat tube is divided into a number of eight flow chambers over the width, with the middle six having an internal width of 3.2 mm. The partition walls 46 have a width 47 of 0.3 mm.

On account of the significantly different wall thicknesses from radius region to flank region, the overall result is a considerably lower total weight of the flat tube, since there is a relatively great wall thickness in the region of the radii 43, whereas a wall thickness of this level is not required in the region of the flanks.

FIG. 11 illustrates a side view of a heat exchanger 60, which likewise comprises headers 2 and 11.

Partitions 50 and 51 divide the headers 2 and 11 into a plurality of longitudinal sections, resulting in a meandering flow path of the evaporation medium over the heat exchanger 60.

In this exemplary embodiment, the connections 6 and 7 for the inlet and outlet are provided on the end sides of the header 2 at the manifold chambers 3 and 4.

For details as to the further design of the heat exchanger and in particular the design and flow ratios of the headers and the remainder of the heat exchanger, reference is made to DE 19 82 688 A1, in the name of the present Applicant, and in particular column 1, line 1 to column 6, line 16, in combination with FIGS. 1 to 6, the content of disclosure of which is hereby incorporated by reference.

Further details of the heat exchanger may also be realized in accordance with DE 100 56 074 A1 in the name of the of the present Applicant, as described in that document in column 1, line 1 to column 8, line 22 with reference to FIGS. 1 to 5, the content of which is likewise incorporated in the content of disclosure of the present application.

Claims

1. A heat exchanger (1), in particular an evaporator for a vehicle air-conditioning system, having at least one header (2) with at least two manifold chambers (3, 4), substantially each manifold chamber (3, 4) in each case being delimited substantially via a base means (12) and a top part means (13), the top part means (13) of a first manifold chamber (3) comprising a first middle side wall (15), and the top part means (23) of a second manifold chamber (4) comprising a second middle side wall (25), the base means and the top part means being produced from a single part, with auxiliary bending elements being provided at least at locations in which the base means and the top part means and/or the top part means and a side wall adjoin one another.

2. The heat exchanger as claimed in claim 1, characterized in that the auxiliary bending elements are regions of reduced wall thickness, such as preferably individual lines and/or points or a plurality of lines and/or points.

3. The heat exchanger as claimed in claim 1, characterized in that the auxiliary bending elements are introduced by stamping operations.

4. The heat exchanger as claimed in claim 1, characterized in that the auxiliary bending elements have a wall thickness reduction in the range from 10% to 50% compared to the normal wall thickness.

5. The heat exchanger as claimed in claim 1, characterized in that the auxiliary bending elements have a wall thickness reduction in the range from 20% to 40% compared to the normal wall thickness.

6. The heat exchanger as claimed in claim 1, characterized in that the first middle side wall (15), at least over a section, is arranged adjacent to the second middle side wall (25), a lateral distance between the first middle side wall (15) and the second middle side wall (25), over at least part of a height (69) of the header (2), increasing with the height above the base means (12) or remaining constant.

7. The heat exchanger as claimed in claim 6, characterized in that the gap (22) between the first and second middle side walls (15; 25) is substantially V shaped.

8. The heat exchanger as claimed in claim 6, characterized in that at least one stability means is arranged on at least one side wall (14, 15; 24, 25) in order to increase the stability.

9. The heat exchanger as claimed in claim 8, characterized in that a longitudinal direction of at least one stability means (31, 35) is oriented substantially perpendicular to the base means (12).

10. The heat exchanger as claimed in claim 8, characterized in that at least one stability means (35) is formed as a recess means (35).

11. The heat exchanger as claimed in claim 8, characterized in that at least one stability means (35) is substantially in the form of a groove means (35).

12. The heat exchanger as claimed in claim 8, characterized in that at least one stability means (35) is substantially in the form of a notch (35).

13. The heat exchanger as claimed in claim 8, characterized in that at least one stability means (31) projects outward.

14. The heat exchanger as claimed in claim 13, characterized in that at least one stability means (31, 35) is in the form of a bead means (31).

15. The heat exchanger as claimed in claim 8, characterized in that a depth (36) of at least one stability means (31, 35) increases with the distance (29) from the base means (21).

16. The heat exchanger as claimed in claim 1, characterized in that a base recess (30) is arranged in a region of contact between the middle side walls (15, 25) and the base means (12).

17. The heat exchanger as claimed in claim 1, characterized in that at least one flat tube (40) has a lower wall thickness (42, 45) in the region of a flank (49) than in the region of a radius (43).

18. The heat exchanger as claimed in claim 17, characterized in that at least one flat tube (40) has a wall thickness (45) which is at least 20% lower in the region of the flanks (49) than in region of the radius.

19. The heat exchanger as claimed in claim 17, characterized in that at least one flat tube (40) has a wall thickness of approximately 0.3 mm at at least one location in the region of the flanks (49).

20. The heat exchanger as claimed in claim 17, characterized in that at least one flat tube (40) has a wall thickness (44) of approximately 0.5 mm at at least one location in the region of a radius (43).

21. The heat exchanger as claimed in claim 1, characterized in that at least one top part means (13, 23) is produced as a single piece.

22. The heat exchanger as claimed in claim 1, characterized in that at least one top part means (13, 23) is produced as a single piece with the base means (12).

23. The heat exchanger as claimed in claim 1, characterized in that at least one connection opening (6, 7) is arranged on a longitudinal side section (8) of the header (2).

24. The heat exchanger as claimed in claim 1, characterized in that the header (2) is connected to two rows of heat transfer tubes (9) arranged one behind the other.

25. The heat exchanger as claimed in claim 1, characterized in that the base means (12) is formed out of a prepared metal plate.

26. The heat exchanger as claimed in claim 1, characterized in that at least one side wall (14, 15, 24, 25) is provided with at least one tab (19) which is inserted into a cutout (21) in the base means.

27. The heat exchanger as claimed in claim 1, characterized in that a closure cover (5) is arranged on at least one end (38) of at least one manifold chamber (3, 4).

28. The heat exchanger as claimed in claim 1, characterized in that at least one connection opening (6, 7) is arranged at an end (38) of at least one manifold chamber (3, 4) of the header (2).