EP2098813A2 - Method for manufacturing heat transfer devices - Google Patents

Abstract

The method involves arranging outer housings around inner housings (18, 19), and forming a cooling agent between the inner and outer housings. The inner and outer housings are manufactured using a pressure casting technique. Two lower parts (2, 3) of the inner housings or the outer housings are constructed. A housing part (1) is manufactured using the technique. Inlets and outlets of the inner housings are connected together at head sides (6) of the lower parts in a common cross section (10), and the housing part is separated along the cross section.

Description

The invention relates to a method for producing heat transfer devices with U-shaped flow-through inner housing, which are each composed of an upper part and a lower part and with outer housings which are arranged around the inner housing, that between the inner housings and the outer housings each a coolant channel is formed , wherein at least one of the inner housing or outer housing is produced by die-casting.

Heat transfer devices are well known using different manufacturing methods. Especially in the field of automotive and engine technology, heat transfer devices are becoming increasingly important. They are used both for cooling recirculated exhaust gas and for charge air cooling or oil cooling. By using such heat transfer devices, for example, the temperature of the gas guided to the cylinder can be reduced and thus the filling of the cylinders and the efficiency of the internal combustion engines can be improved.

Among other methods of making heat transfer devices, it is known to mold die-cast shells having fins formed thereon into heat transfer devices. The use of die-cast aluminum to produce such heat transfer devices has the advantages of high cooling efficiencies while cost-effectively manufacturing.

So will in the DE 10 2005 058 204 A1 discloses a heat transfer device having a U-shaped flow-through housing, so that input and Outlet of the gas to be cooled at the head side of the heat transfer device are arranged side by side. This heat transfer device is constructed of an inner housing and an outer housing, which are pushed into each other. Both the outer housing and the inner housing consist of a top and a lower part, which are joined together by welding prior to assembly of the inner housing with the outer housing. The inner housing disclosed here has at its upper part and at its lower part in each of the projecting through the gas to be cooled channel ribs, which extend in cross section of the inner housing alternately from the upper parts or from the lower part into the channel. The upper part is designed lid-shaped, while the lower part has a pot shape.

For the production of such parts in the die-casting process, it is necessary to carry out the lower part with an upper housing part wall in the region of the head side, since otherwise no circumferential weld seam could be achieved. At the same time, however, this means that an additional lateral slide, which is removed to the head side, is needed to produce such a lower part. Another slider is led out in the extension direction of the ribs upwards out of the lower part.

Such an embodiment thus has the disadvantages that additional slides must be used in a second processing level, resulting in additional costs. In addition, the rib spacing in the region of the inlet and outlet must be chosen to be relatively large, since for reasons of strength, the distance between the ribs of a part must not be chosen too small. While ribs of the top and bottom alternately point into the channel after assembly in the region of the lid to keep the fin spacing small, such an embodiment includes ribs extending into the channel from above in the region of the inlet or outlet such a production is not possible.

This deteriorates the efficiency of the heat transfer device and involves a great deal of effort in producing the welds when assembling the two parts. Furthermore, high tooling costs arise due to the laterally evacuated slide element and the additional machining plane.

It is therefore an object of the invention to provide a method for adjusting a heat transfer device can be dispensed with in a second Schieberentformungsrichtung and thus on the second slide, and also in the inlet and outlet ribs can be formed. Thus, the efficiency of the heat transfer device should also be improved.

This object is achieved in that a first housing part, in which two lower parts of the inner housing or the outer housing are formed, is manufactured in a die-casting process, wherein the two lower parts are arranged at their top sides, on which the inlets and outlets of the inner housings, are connected together in a common cross-section and in a later method step, the first housing part is separated along the common cross-section. By such a method, the lower parts in the
Die casting process are removed from the mold so that a laterally to be removed on the head side slide can be omitted and thus the tool costs and the production cost can be reduced.

In a further method, a second housing part, in which two upper parts of the inner housing or the outer housing are formed, produced in a die-casting process, wherein the two upper parts at their top sides, where the entries and exits of the inner housing are arranged, in a common cross-section with each other are connected, then the first and the second housing part placed on each other and the two housing parts are interconnected, whereby two inner housing or outer housing are formed, which are arranged at their respective head sides, where the inlets and outlets of the inner housing in the common cross section and then the first is separated with the second housing part along the common cross-section of the inner housing or the outer housing. This means that after the pressure casting of the two upper parts and the two lower parts, these can be connected to each other by a common closed circumferential weld, which leads around the entire circumference of the casting. This results in the advantage that an upper part no longer has to be designed as a pure cover part, which must be fastened with a circumferential weld. Thus, even through the elimination of the lateral slide, the geometry in the inlet and outlet of the two inner or outer housing can be chosen freely. Overall, there is a shortening of the weld seam lengths and the input and Ausschauchphasen during welding, whereby reduced process times and thus lower production costs can be achieved.

Preferably, the separation of the housing parts takes place mechanically, in particular by sawing. Such a separation is easy to carry out without great expense.

Preferably, the connection of the two housing parts by welding, in particular friction stir welding, which is particularly suitable when connecting two parts in die-cast aluminum and leads to leakage-free components.

In a further improvement of the method, the pressure casting molds of the two housing parts of the inner housing are formed such that extend from the upper parts and the lower parts in cross section of the inner housing in all rows of ribs alternately ribs in the limited by the inner housing channels. This means that now also in the region of the inlet and outlet, the upper part of the inner housing is designed so that the ribs of the upper part protrude into the intermediate space between the ribs of the lower part. Such an arrangement of the ribs is not possible in the known die-cast heat transfer devices of this type, since the weld seam of the cover was arranged in this region. Another Arrangement of a circumferential weld, which ensures the necessary strength, was not possible in these versions.

In a further embodiment of the method, after separation of the inner housing and / or the outer housing, in each case one of the inner housing is pushed from the head side into one of the outer housing, and the inner housing is subsequently connected to the outer housing. As a result, the assembly of the entire housing is completed in a simple manner.

• Figur 1 zeigt eine dreidimensionale Darstellung eines ersten Gehäuseteils, welches zwei Unterteile eines Innengehäuses einer Wärmeübertragungsvorrichtung bildet.
• Figur 2 zeigt eine dreidimensionale Darstellung des ersten und eines zweiten Gehäuseteils, vor dem Zusammenbau.
• Figur 3 zeigt eine Kopfansicht des Innengehäuses einer Wärmeübertragungsvorrichtung nach dem Zusammenbau von Oberteil und Unterteil und der Trennung der beiden Innengehäuse.
• In der Figur 1 ist ein erstes Gehäuseteil 1 dargestellt, in dem zwei jeweils U-förmig durchströmbare Unterteile 2, 3 ausgebildet sind. Dieses erste Gehäuseteil 1 wird im
  Druckgussverfahren hergestellt, wobei durch die Pfeile 4, 5 die Entformungsrichtung der benötigten Schieber zum Druckgießen dieses ersten Gehäuseteils 1 dargestellt sind.

Such a method for producing a heat transfer device is simple and inexpensive to perform compared to known production methods, with low process times and tooling costs are the result. In addition, a high cooling efficiency is achieved and process times for production are reduced.
An embodiment is shown in the drawings and is described below:

• FIG. 1 shows a three-dimensional representation of a first housing part, which forms two lower parts of an inner housing of a heat transfer device.
• FIG. 2 shows a three-dimensional representation of the first and a second housing part, prior to assembly.
• FIG. 3 shows a top view of the inner housing of a heat transfer device after assembly of upper part and lower part and the separation of the two inner housing.
• In the FIG. 1 a first housing part 1 is shown, in which two U-shaped through-flowable lower parts 2, 3 are formed. This first housing part 1 is in
  Die casting process produced by arrows 4, 5, the Entformungsrichtung the required slide for die casting this first housing part 1 are shown.

The two lower parts 2, 3 lie with their respective head side 6, are formed at the entrances 7 and 8 outlets of the two lower parts 2, 3, against each other. This head side 6 is thus open after a separation of the two lower parts 2, 3. Through the respective inlet 7, during the later use of the heat transfer device, gas can flow through the channel 20 as far as a deflection 21 and from there flow back to the outlet 8. A central wall 9 separates the inflowing gas flow from the outflowing gas flow, so that the incoming gas is forced to flow through this lower part 2, 3 in a U-shaped manner. Thus, it becomes possible to arrange the inlet 7 and the outlet 8 side by side.

The head sides 6 of the two lower parts 2, 3 thus have a common cross-section 10, in which the inlets 7 and 8 outlets are arranged and on which the two lower parts 2, 3 can be separated from each other. Such a separation is preferably carried out mechanically, for example by sawing or the like.

The FIG. 2 shows in addition to the first housing part 1, a second housing part 11, in which two to the lower parts 2, 3 from FIG. 1 matching tops 12, 13 are formed. With such an embodiment of the upper parts, only the slides in the indicated arrow directions 4, 5 can be removed from the die-cast part during the die-casting process. Lateral slides are not needed. In FIG. 3 It can be seen that in the second housing part 11, in the two upper parts 12, 13, in each case a groove 14 is formed, into which later the middle walls 9 of the lower parts 2, 3 extend, so that a closed over the entire height middle wall to U shaped forced flow of the heat transfer device can be achieved.

In FIG. 2 It can be seen that the second housing part 11 can be placed on the first housing part 1, so that, seen in the flow direction, one behind the other rib rows 16 form, consisting of different, juxtaposed ribs 17, 22. It should be noted that each first rib 17 protrudes from the lower part 2, 3 into the channel 20 and every second rib 22 protrudes from the upper part 12, 13 into the channel 20. In a production by die casting are the resulting small distances between the ribs 17, 22 in one of the two parts not possible because a Schieberentformung at such small distances to the rupture of the ribs 17, 22 would result.

The method used here for producing such heat transfer devices now has the steps of initially producing the first housing part 1 with the two lower parts 2, 3 formed therein by die casting and subsequently or simultaneously a correspondingly fitting second housing part 11 with the upper parts 12, 13 , is produced by die-casting, in each case only two slides are used, which are removed in the opposite direction from the workpiece.

The two housing parts 1, 11 are then placed on each other and joined together by welding, in particular by friction stir welding, whereby two inner housing 18, 19 are formed. It is clear that the resulting weld over both lower parts 2, 3 and tops 12, 13 can be performed in a single pass completely circumferential. A placement or discontinuation of a corresponding tool is no longer necessary here. Also, no weld ends on the head sides 6, as would be the case with such a construction, when the lower and upper shells 2, 3; 12, 13 would be poured individually. Such weld ends are to be avoided since no straight closed head side 6 would be reached. Also, component resistance problems would occur when performing a friction stir weld. In the embodiment shown, this strength is achieved by the directly adjacent second inner or outer housing 18, 19, so that two inner housing 18, 19 can be made with a weld.

In the case of a production of individual inner housing or outer housing, it should thus be ensured in the construction that, in the region of the head sides, as already described above, the respective end of the weld seam would have to lie in front of the last row of ribs. This means that, in such a case, the upper part 12, 13 could only be designed as a cover on which no ribs 22 could be formed, which protrude into the region of the inlet 7 and the outlet 8, respectively would. As a result, in each case a row of ribs 16 with a smaller number of ribs 17 projecting from the lower part 2, 3 into the channel 20 in the inlet and outlet region, whereby the cooler efficiency is lower in such heat transfer devices.

After welding together the upper parts 12, 13 with the lower parts 2, 3 of the inner housing 18, 19, the two resulting inner housing 18, 19 are mechanically separated from each other along the common cross-section 10.

Of course, in the same way, an unillustrated outer housing can be produced, which is also designed in two parts, that consists of a lower part and a shell. These could also be welded together in the same way and then separated.

To complete a heat transfer device then, after separating the two outer casings and inner casings 18, 19, the inner casings would be pushed into the outer casings in order to obtain a finished heat transfer device.

The production with this method according to the invention is thus significantly optimized compared to known embodiments, since the entire weld length and the necessary input and Ausschauchphasen for the production of the heat transfer device can be significantly reduced. Furthermore, the hitherto required, laterally to be removed slides are saved in the die casting process, so that also eliminates tooling costs. At the same time, the possible arrangement of closely juxtaposed ribs in the region of the inlet 7 or outlet 8 significantly increases the cooler efficiency.

It should be clear that design changes with respect to the design of such a heat exchanger are possible.

Claims (6)

Process for the production of heat transfer devices with U-shaped through-flowed inner housings (18, 19), which are each composed of an upper part (12, 13) and a lower part (2, 3) and outer casings which are so around the inner housing (18, 19 ) are arranged, that between the inner housings (18, 19) and the outer housings each a coolant channel is formed, wherein at least one of the inner housing (18, 19) or outer housing is produced by die-casting,
characterized in that a first housing part (1), in which two lower parts (2, 3) of the inner housing (18, 19) or the outer housing are formed, is produced in a die casting process, wherein the two lower parts (2, 3) at their Head sides (6) on which the inlets (7) and the outlets (8) of the inner housing (18, 19) are arranged, in a common cross-section (10) are interconnected and in a later process step, the first housing part (1) along of the common cross section (10) is separated. Process for the production of heat transfer devices according to claim 1,
characterized in that a second housing part (11), in which two upper parts (12, 13) of the inner housing (18, 19) or the outer housing are formed, is produced in a die-casting process, wherein the two upper parts (12, 13) at their Head sides (6) on which the inlets (7) and outlets (8) of the inner housing (18, 19) are arranged, in a common cross-section (10) are interconnected, then the first housing part (1) and the second housing part (11) is placed on top of one another and the two housing parts (1, 11) are connected to one another, whereby two inner housings (18, 19) or outer housings are formed, which at their respective head sides (6), at which the inlets (7 ) and outlets (8) of the inner housing (18, 19) are arranged in the common cross section (10) are interconnected, and then the first housing part (1) with the second housing part (11) along the common cross section (10) Inner housing (18, 19) or the outer housing is separated. Method for the production of heat transfer devices according to claim 1 or 2,
characterized in that the separation of the housing parts (1, 11) takes place mechanically, in particular by sawing. Method for producing heat transfer devices according to one of claims 2 or 3,
characterized in that the connection of the two housing parts (1, 11) by welding, in particular friction stir welding, tracked. Method for producing heat transfer devices according to one of the preceding claims,
characterized in that the die-casting molds of the two housing parts (1, 11) are formed in such a way that, in cross-section, of the upper parts (12, 13) and the lower parts (2, 3) in all rib rows (16, 19) ) alternately ribs (17, 22) in the through the inner housing (18, 19) limited channels (20) extend. Method for producing heat transfer devices according to one of the preceding claims,
characterized in that after the separation of the inner housing (18, 19) and / or the outer housing in each case one of the inner housing (18, 19) from the head side of the Outside housing is pushed into one of the outer housing and then the inner housing (18, 19) is connected to the outer housing.

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