EP0444595B1 - Heat exchanger, more particularly oil cooler for motor vehicle - Google Patents

Description

The invention relates to a heat exchanger, in particular an oil cooler for motor vehicles, consisting of a plurality of flat tube sections through which a first heat exchange medium flows, which are closed on both sides by flat squeezing and / or by a flat squeezed standing seam and which are arranged in parallel with the interposition of fins like ribs and the second heat exchange medium flowing against them.

Heat exchangers of this type are known (DE-U-89 03 873). The heat exchanger of this known type is produced in that a flat tube is bent in a zigzag or serpentine manner in such a way that the flat tube sections running between the bending points are parallel to one another. The sealing of the flat tube sections, which are provided through transverse bores with connection supports for the heat exchange medium, is achieved by squeezing the tube walls flat at the bending points on the one hand and at the two initially open ends of the tube by means of a squeezed standing seam. Sealing such standing seams creates certain difficulties, even when soldering is carried out.

It is also known to form heat exchangers by means of a plurality of individual flat tubes arranged in a stack on top of one another (EP-A-106 479), the ends of which are sealed by additionally attached end pieces, each of which is parallel have bulges in the form of caps that are matched to one another and to the spacing of the flat tubes, between which the open end regions of the flat tubes are pushed in and then soldered. Heat exchangers manufactured in this way are relatively complex.

From GB-A-444 964, finally, a heat exchanger is also known, the tubes of which are arranged in rows and in parallel at a distance from one another. The tubes are staggered in rows in suitable recesses of several plates arranged one behind the other. On each of the tubes, a wave-shaped longitudinal rib is folded over towards the tube, which has the purpose of breaking up the outflow that occurs behind the tube into several narrow air streams, which are then alternately passed on to the adjacent tubes of the row of tubes behind them. The sealing problem is not addressed there.

The invention has for its object to design a heat exchanger of the type mentioned in such a way that the end closure of the flat tubes is carried out without great effort, but in such a way that the tightness is guaranteed in any case.

To solve this problem, it is provided in a heat exchanger of the type mentioned at the outset that the standing seams arranged on the tube ends are provided with a shaft contour running in the longitudinal direction of the fold. This can be done in a simple manner after folding by means of an appropriate pressing tool which presses the standing seam into a corrugated contour. On the one hand, this configuration results in a very stable closing fold. It also ensures tightness because of the inherently stable fold, even when the heat exchanger is exposed to relatively strong mechanical loads during operation, as is the case when used for oil coolers for motor vehicles.

Advantageous developments of the invention are characterized in the subclaims. The features of claim 2, in conjunction with the fold design according to claim 1, have the advantage that the complex bending of a flat tube can be omitted, but without the manufacturing effort being too great due to additionally attached end caps or the risk of the flat tubes becoming leaky. The features of claim 3 allow the production of a simply constructed pressing tool.

The embodiment according to claims 4 to 6 has the advantage that in the area of the openings for connecting serve the flat tubes with each other, no deformation or distortion occur. The features of claim 7 ensure a particularly tight fold and the features of subclaim 8 outline advantageous options for arranging the position of the fold with respect to the flat tube.

Fig. 1

eine schematische und perspektivische Darstellung eines erfindungsgemäßen Wärmetauschers, der aus mehreren stapelartig übereinander angeordneten Flachrohrstücken besteht,

Fig. 2

die vergrößerte Teilansicht des mit einem Falz verschlossenen Stirnendes eines der Flachrohre des Wärmetauschers der Fig. 1 in Richtung des Pfeiles II gesehen,

Fig. 3

den Schnitt längs der Linie III in Fig. 2,

Fig. 4

den Schnitt längs der Linie IV in Fig. 2,

Fig. 5

eine Darstellung ähnlich Fig. 2, jedoch bei einer anderen Ausführungsform des Stehfalzes,

Fig. 6

den Schnitt längs der Linie VI durch Fig. 5,

Fig. 7

eine Darstellung ähnlich Fig. 2, jedoch bei einer anderen Variante des Stehfalzes,

Fig. 8

den Schnitt längs der Linie VIII in Fig. 7,

Fig. 9

die Darstellung einer weiteren Variante des Stehfalzes ähnlich Fig. 2 und

Fig. 10

den Schnitt durch den Falz der Ausführungsform der Fig. 9 längs der Linie X.

In the drawing, the invention is illustrated using exemplary embodiments and is explained in the following. Show it:

Fig. 1

2 shows a schematic and perspective illustration of a heat exchanger according to the invention, which consists of a plurality of flat tube pieces arranged one above the other in a stack,

Fig. 2

the enlarged partial view of the front end closed with a fold seen one of the flat tubes of the heat exchanger of FIG. 1 in the direction of arrow II,

Fig. 3

the section along the line III in Fig. 2,

Fig. 4

the section along the line IV in Fig. 2,

Fig. 5

2, but in another embodiment of the standing seam,

Fig. 6

the section along the line VI through Fig. 5,

Fig. 7

a representation similar to FIG. 2, but in another variant of the standing seam,

Fig. 8

the section along the line VIII in Fig. 7,

Fig. 9

the representation of a further variant of the standing seam similar to Fig. 2 and

Fig. 10

the section through the fold of the embodiment of FIG. 9 along the line X.

In Fig. 1, a heat exchanger is schematically indicated in its basic structure, which is to be used for the oil cooler of a motor vehicle. The heat exchanger (1) of Fig. 1 consists of several flat tubes (2) of a certain length, which are arranged parallel to each other with their larger areas and are stacked on top of each other in the finished state with the interposition of lamellar fin plates (3). Each of the flat tubes (2) is provided in the region of its ends with an opening (4) through which, as indicated by the arrow (5), one of the heat exchange media, for example the oil to be cooled, into the interior via connecting pieces (not shown) of the flat tube (2) can be guided, which is also filled in a known manner with inserted turbulence plates (6). The openings (4) of each flat tube (2) are also connected to one another via intermediate sleeves, so that a heat exchange medium in the direction of the arrow (5) can enter all flat tubes and leave them again through an outlet connection connecting one of the opposite openings (4) . By stacking the flat tubes (2) and the finned sheets (3) between them, a so-called finned tube block is formed, which is flowed in a known manner in the direction of arrow (7) across the flat tubes (2) with the second heat exchange medium, for example with cooling air can.

Each of the flat tubes (2) consists of a tube piece that is initially open at both ends. The ends are sealed in that the walls of the flat tubes (2) are each compressed and folded into a standing seam (8) which, as can be seen in particular from FIG. 2, has a wave-like contour. This can be achieved in a simple manner, for example, by first following the upper wall (9) of the flat tube (2) in the end region (9a) according to FIG. 3 is pressed down to about the level of the lower wall (10) by a tool into which the flat tube is inserted. As a result, the parts (10b and 9b) of the walls (10 and 9) are initially parallel to one another. They are then folded over to the standing seam (11), which is initially still flat, but has four times the thickness of the walls (9 and 10). The standing seam (11) is then pressed together in a pressing tool, which has the shaft contour of the illustration in FIG. 2, in such a way that it reaches the approximately sinusoidal shaft contour shown in FIG has top (11 ') directed above. Since the corrugated contour is uniform, all apices (11 'and 11'') are seen over the entire length of the standing seam (11), each at the same distance from each other. The height (a) which the standing seam (11) thus formed occupies is the same size across the width (b) (FIG. 1) of each flat tube (2). 2 and 3, the configuration has been carried out so that the center line (12) of the sinusoidal shape of the standing seam (11) coincides approximately with the center longitudinal plane (13) of the flat tubes (2).

It is also possible to make the distances between the apexes (11 ') (the division) and the height (a) of the corrugations (the amplitude) in the central region of the fold (11) smaller than in the outer regions. It can be avoided that too much material is drawn into the fold when the fold (11) is squeezed in this central region, which lies on the end face of the flat tubes (2) in front of the openings (4). The area of the opening (4), via which each flat tube is connected to an adjacent one, is therefore less likely to be deformed or rejected. The connection of connecting pieces to neighboring pipes can therefore not be affected.

5 to 10 show deviations from such a design.

The design in the embodiment according to FIGS. 5 and 6 is such that the standing seam (11), the contour of which otherwise corresponds to that of FIGS. 2 to 4, in relation to the central longitudinal plane (13) of each flat tube (2) it is arranged that the apexes (11 ') are affected by the central longitudinal plane (13). As a result, the apices (11 '') protrude clearly beyond the lower wall (10). The resulting fold (11) becomes very stable because it is pulled obliquely downwards, as shown in FIG. 6. The individual layers of the folded-over wall parts (9b, 10b) abut each other in all areas. This design can also be used so that the standing seam (11) is used for the axial guidance of the rib plates (3).

The embodiment of FIGS. 7 and 8 provides that the center line (12) of the sinusoidal shape of the standing seam (11) coincides approximately with the plane of the lower wall (10). This results in the fold shape shown in FIG. 8. The embodiment of FIGS. 9 and 10 in turn provides that the standing seam (11) is shifted even further towards the center, but not yet as far as in FIGS. 2 and 3. Here the center line (12) of the sinusoidal shape of the standing seam (11) lies somewhat above the inner surface of the lower wall (10). All of the embodiments shown have the advantage of a very stable corrugated standing seam (11) which, as can be seen in each case from the sectional drawings in FIGS. 3, 4, 6, 8 and 10, also has very long sealing surfaces which are bent against one another and which have a good quality and enable permanent sealing of the flat tubes (2), in particular if soldering is subsequently carried out.

Claims (8)

1. A heat exchanger, particularly an oil cooler for motor vehicles, consisting of a plurality of flat tube portions (2) through which a first heat exchanging means passes and which are closed at both ends by being squashed flat and/or by a squashed-flat elbow seam and which rest on one another in a parallel relationship through interposed leaf-like ribs (3) against which the second heat exchange medium flows, characterised in that the edges (8) of the seam which are at the tube ends have an undulating contour (11', 11'') extending in the longitudinal direction of the seam (11).
2. A heat exchanger according to Claim 1, characterised in that each portion of flat tube consists of a flat tube (2) closed at both ends by a seam (11).
3. A heat exchanger according to Claim 1, characterised in that the undulating contour extends sinusoidally and has apices (11', 11'') which are disposed at equal distances from and have the same amplitude as one another.
4. A heat exchanger according to Claim 1, characterised in that in the longitudinal direction of the seam (11), the undulating contour is of unequal pitch and/or amplitude.
5. A heat exchanger according to Claim 4, characterised in that in the middle portion of the seam (11), the spacing is smaller than it is in the outer portions.
6. A heat exchanger according to Claims 4 and 5, characterised in that the amplitude (a) of the undulating contour is smaller in the central portion of the seam (11) than it is in the outer portions.
7. A heat exchanger according to Claim 1, characterised in that each seam (11) has four times the wall thickness of the flat tube (2).
8. A heat exchanger according to Claim 1 and 3, characterised in that the central line (12) through the sinusoidal pattern is aligned substantially in the longitudinal central plane (13) of the associated flat tube (2) or is shifted to one side.

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