EP2625430B1 - Method of manufacturing a turbocharger casing - Google Patents

Description

The invention relates to a method for producing a housing, in particular a housing of a turbocharger.

From the prior art is known to produce turbocharger housing by casting. See for example JP H07 303934 A , Here, the structure of the mold is designed so that a separate oil and water core is used, which are stored in an outer mold.

The object of the present invention is to provide an improved method for manufacturing a turbocharger housing.

This object is achieved by a method for producing a turbocharger housing having the features of patent claim 1.

Accordingly, the invention provides a method for producing a housing of a turbocharger, wherein at least one molding for forming the casting each having a parting plane which is arranged at a predetermined angle to the longitudinal axis of the casting and wherein at least one core element is provided.

The method has the advantage that the molded part can be imaged in a mold half of a mold box and the core element can be inserted in one mold half. Thereby, a casting with a higher accuracy can be produced because the molding is not divided into two mold parts along its longitudinal axis, which are respectively molded in the two mold halves of a mold box and then form by assembly in the mold box the shape of the casting.

Instead, the mold of the casting is completely formed in one mold half of the mold box, while in the other mold half, for example, substantially only the feeders are arranged.

Furthermore, the first core element forms at least part of the outer surface of the casting.

The method has the advantage here that the outer surface can be produced with more complicated structures or shapes, since the core element can be destroyed mechanically, for example by shaking, after the casting or the binder of the molding sand of the core element is destroyed by the heat during casting, so that the core element disintegrates by itself.

In addition, at least two core elements are provided, wherein the two core elements are mounted one inside the other and are completely received in a mold half of the molding box.

The method has the advantage that in this way a casting can be manufactured with a higher precision. The manufacturing tolerances can be reduced to, for example, process-safe +/- 0.5mm.

Advantageous embodiments and modifications of the invention will become apparent from the dependent claims and the description with reference to the drawings.

In one embodiment of the invention, the casting is a bearing housing or impeller housing of a turbocharger.

In a further embodiment of the invention, the first core element is a water jacket core element. In this way, a corresponding turbocharger housing with cooling can be produced very simply, in which the cooling jacket is integrated in the housing or is formed integrally therewith.

According to the invention, a second core element is provided. The first and second core element are stored one inside the other and completely received in a mold half of a mold box. This has the advantage that a casting with a higher precision can be produced.

According to the invention, the molded part has a dividing plane which is arranged at a predetermined angle to the longitudinal axis of the casting, namely at an angle of 90 °, and wherein the molded part is moldable in a mold half of a molding box. In this case, at least one core element also has a dividing plane, which is arranged at a predetermined angle to the longitudinal axis of the casting, namely at an angle of 90 °. This has the advantage that the shape of the casting can be completely imaged in a mold half, in contrast to castings which have to be split along the longitudinal axis and thus formed in both mold halves of a mold box.

In a further embodiment according to the invention, the second core element is, for example, an oil core element. This has the advantage that in the housing of the turbocharger an oil inlet and outlet can be integrated, for the supply of bearings with lubricant.

According to the invention, at least one core element forms or both core elements a part of the outer geometry or outer surface of the casting. This has the advantage that the outer surface is formed with more complicated structures or shapes can be because the respective core element is destroyed for removal from the casting.

According to the invention, the structure of the molding and the core elements is completely imaged in a mold half of a molding box. This makes it possible to produce a cast part with a higher precision, moreover, there are no unsightly burrs in the area of the dividing plane between the upper and lower mold halves.

In a further embodiment of the invention, the respective core element of molding sand and a suitable binder can be produced, so that it can be easily destroyed again for removal. In principle, however, one or more core elements can also be used made of other materials, for example materials which either evaporate, melt out or otherwise decompose (eg polystyrene), or they are melted out before casting (for example wax, synthetic resins).

Fig. 1

eine Schnittansicht eines Formkastens mit einer Anordnung eines Rohteils und eines Kernelements gemäß dem Stand der Technik,

Fig. 2

eine Schnittansicht eines Formkastens mit einer Anordnung eines Rohteils und zweier Kernelemente,

Fig. 3

eine Schnittansicht eines Formkastens mit einer Anordnung eines Rohteils und zweier Kernelemente gemäß der Erfindung,

Fig. 4

eine Explosionsdarstellung eines Rohteils, sowie eines Wassermantelkerns und eines Ölraumkerns zur Bildung eines Lagergehäuses eines Turboladers gemäß der Erfindung;

Fig. 5

eine Ansicht einer Unterkastenseite eines Formkastens, wobei das Rohteil und der Wassermantelkern und Ölraumkern gemäß Fig. 3 in zusammengesetztem Zustand gezeigt sind; und

Fig. 6

eine Ansicht einer entsprechenden Oberkastenseite des Formkastens.

The invention will be explained in more detail with reference to the exemplary embodiments indicated in the schematic figures of the drawings. Show it:

Fig. 1

a sectional view of a molding box with an arrangement of a blank and a core element according to the prior art,

Fig. 2

a sectional view of a molding box with an arrangement of a blank and two core elements,

Fig. 3

a sectional view of a molding box with an assembly of a blank and two core elements according to the invention,

Fig. 4

an exploded view of a blank, and a water jacket core and an oil chamber core to form a bearing housing of a turbocharger according to the invention;

Fig. 5

a view of a lower box side of a molding box, wherein the blank and the water jacket core and oil chamber core according to Fig. 3 shown in assembled condition; and

Fig. 6

a view of a corresponding upper box side of the molding box.

In all figures, identical or functionally identical elements and devices have been provided with the same reference numerals, unless stated otherwise.

In Fig. 1 First, a mold box 10 is shown for producing a pipe part made of a cast material. The molding box 10 is shown greatly simplified. For the sake of clarity, the representation of feeders for feeding the liquid cast material was dispensed with. Furthermore, no draft was drawn.

The pipe part or the impression 12 of the pipe part in the molding box 10 is divided in the longitudinal direction. This means that a top box 14 and a bottom box 16 of the molding box 10 each have an impression 12 of a cylinder half, wherein both boxes 14, 16 in the assembled state forms the complete cylindrical impression 12 of the pipe part.

To form the cavity of the pipe part, a corresponding cylindrical core element 18 made of molding sand is inserted into the lower box 16, as in FIG Fig. 1 is shown. The core element 18 is mechanically destroyed again after casting, after cooling of the casting, for example by shaking, so as to remove it from the finished casting again. However, there are also, for example, core elements in which the binder of the molding sand is chosen so that it is destroyed by the heat generated during casting as possible and thereby the core element decomposes itself later, without it, as described above, must first be mechanically destroyed.

In Fig. 2 is now an advantageous example, but not part of the invention, for the arrangement of a blank or its molding (model body) and its core elements 18 shown in a molding box 10. Unlike in Fig. 1 In this case, the blank or its molded part is not longitudinally divided; instead, the blank or its shaped part (model body) is shaped in the lower box 16, as shown by the imprint 12 of the molded part in FIG Fig. 2 is indicated. In this case, instead of being longitudinally divided, the mold can be divided horizontally or divided in a plane perpendicular to the longitudinal axis 22 of the blank. In this case, a molded part of the blank can be molded in the lower box 16 and a molded part of the blank also in the upper box 14, as in Fig. 2 is indicated by a dashed line.

Furthermore, two corresponding core elements 18 are used to form the cavities of the casting. About one or more feeders 24, which are arranged for example in the upper box 14, the liquid casting material is introduced.

The representation in Fig. 2 is greatly simplified and purely schematic. In particular, the shape of the core elements 18 and the imprint 12 of the blank or its molding (model body) are shown greatly simplified and merely exemplary. Here, for example, no draft angles, etc. have been shown. The same applies, for example, to the shape, the arrangement and the number of feeders 24 for introducing the liquid casting material. Furthermore, the in Fig. 2 shown wall portions 26, 28 of the blank so thought that they are connected to each other, but what in Fig. 2 not shown. The simplified representation in Fig. 2 is merely illustrative of an example of the arrangement of a Molding and corresponding core elements 18.

In the example, as it is in Fig. 2 is shown, the first core element 18 forms a first cavity of the later casting. The second core member 18 further formed a second cavity of the later casting. In this example, the outer wall 30 of the later cast part is formed in the lower box 16 by the impression 12 of the molded part (model body).

In Fig. 3 Now an embodiment of the arrangement of a blank or its molding (model body) and its core elements 18 in a molding box 10 according to an example of the invention is shown. In this case, the impression 12 of the blank or the molding (model body) is first formed in the molding box 10 and then the blank or molding removed again. Thereafter, a plurality of core elements 18 are arranged or positioned in the impression 12 of the molding. In the present case, the first core element 18 is designed so that it is inserted into the impression 12 of the blank or its molding to form the outer wall 30 of the subsequent casting.

While the first core element 18 forms the outer wall 30 of the later casting, in turn, the second core element 18 forms the cavity of the later casting and its inner wall. The second core element 18 is inserted into the first core element 18 accordingly. As the example in FIG.

2 is also the embodiment in Fig. 3 shown schematically and greatly simplified.

Furthermore, in Fig. 4 an exploded view of another embodiment of the invention shown. In Fig. 4 are shown as core elements 18, the core elements 38, 40, for forming a bearing housing of a turbocharger. This is a blank or its molding 20 (model body) ( Fig. 4 ), which in the present example ( Fig. 4 ) with a Oil drain 36 and the water connection holes (from subsequent water jacket core element 38) is formed.

Furthermore, as core elements 18, a water jacket core element 38 and an oil chamber core element 40 are provided, for forming a water jacket around the bearing housing in order to be able to additionally cool it during operation later. Furthermore, the oil chamber core member 40 is provided to supply a lubricant to the bearings of the bearing housing later.

Unlike the state of the art, as in Fig. 1 is shown, the blank or its molding 20 (model body) is not divided in the longitudinal direction or along its longitudinal axis. Instead, the new concept according to the invention is based on a compact mold design. For example, the water jacket core element 38 and the oil chamber core element 40 each form a partial contour of the outer geometry of the housing. The respective division plane of the molded part 20, the water jacket core element 38 and the oil chamber core element 40 of the bearing housing to be produced do not extend in the longitudinal direction or along the longitudinal axis 42 as in the prior art, as in an example in FIG Fig. 1 is shown, but the pitch planes extend, for example, substantially perpendicular to the longitudinal axis 42 of the housing to be produced. The division plane 44 of the oil chamber core element 40 is hatched as an example Fig. 4 indicated.

Due to the more compact shape structure, as it is for example in Fig. 4 is shown, a more precise positioning of the inner geometry to the outer geometry of the housing can be achieved. Initial receiving points (not shown) for mechanical processing can also be placed on the surfaces of the outer geometry formed by the oil space core element 40 and the water jacket core element 38.

Due to the shape and core structure can be, for example, a water-cooled bearing housing by means of a Ölraumkernelements 40 and a water jacket core element 38, and a mold half, here the lower box 16, geometrically complete represent. In other words, the shape of the casting to be produced is completely formed in the lower case with the necessary core elements, comparable to the example in FIG Fig. 3 is shown.

As in the perspective view in Fig. 5 is shown, the blank or its molding (model body) is first molded in the mold box to form a corresponding impression 12 and then removed again. In the impression 12 of the blank or molding (model body) a plurality of core elements 18 are used or positioned.

The two core elements 18, ie the water jacket core element 38 and the oil chamber core element 40, are mounted one inside the other (see also FIG Fig. 6 ) and positioned to the lower box form or here to the imprint 12 of the molding (model body) in the lower box shape. The lower box shape has been omitted here for the sake of clarity.

In the present case, as in Fig. 5 12, the oil core core member 40 is stored in the water jacket core member 38 and positioned to the lower box mold (not shown) and the impression 12 of the molding 20 and the blank, respectively, in the lower box mold. This allows a massive tolerance narrowing to, for example, process-safe +/- 0.5mm to the reference surface. Due to this higher precision of the arrangement described can be given a larger space due to the small tolerance window for the wall thickness between two core elements 18, 38, 40 and between an inner contour and an outer contour Cross-sectional area are allowed in the water channel. This larger cross-section provides improved heat dissipation and also allows process-reliable removal of casting residues in the water channel and oil space of smaller turbocharger housings, such as those used in motor vehicles, through better accessibility.

In Fig. 6 is shown a perspective view from the top box side of the molding box. The upper box and lower box were also omitted here for the sake of clarity. From the simplistic and schematic view in Fig. 6 it can be seen that the core elements 18 are mounted one inside the other, ie the oil chamber core element 40 is arranged or stored in the water jacket core element 38.

Although the present invention has been described above with reference to the preferred embodiments, it is not limited thereto, but modifiable in a variety of ways, as far as the method falls under the wording of the appended claims.

According to the embodiment for producing a bearing housing, it is also possible, for example, to produce a turbine housing or compressor housing in this way. The turbine housing can for example also be formed with a water jacket, for cooling.

The core elements 18, 38, 40, as used in the examples in the Fig. 2 to 5 can be made, for example, from a sand with a suitable binder, as previously described with reference to the prior art Fig. 1 has been described. However, other materials or material combinations may be used for making core elements 18, 38, 40 are used.

Furthermore, the number of core elements, their shape and arrangement, etc., and the number of moldings, their shape and arrangement, etc., can be arbitrarily varied depending on the casting to be manufactured, as far as the method falls under the wording of the first claim. The same applies to the provision of an oil inlet and / or outlet, as well as water connection holes. These can be designed as desired and provided or omitted as needed. For example, a turbocharger housing may be provided with or without one or more cooling jackets.

As a casting material for the bearing housing, for example, a cast steel and cast iron alloy, and their modifications, such as D5, Simo, 1.4848, 1.4849, etc. are provided. However, these are merely examples of materials from which the housing can be made. The invention is not limited to these materials.

Claims (3)

1. Method for producing a housing of a turbocharger as a casting, wherein a moulding flask (10), which is divided along a parting plane into a drag (16) and a cope (14), is used, wherein the turbocharger housing has a longitudinal axis, wherein an impression (12) is created in the drag (16) by means of at least one pattern (20) to form the casting, wherein the pattern has a parting plane, wherein the parting plane of the pattern is understood as meaning a planar end face of the pattern that is brought into the plane of the drag associated with the parting plane of the moulding flask to create the impression, wherein the parting plane of the pattern is arranged at a predetermined angle of 90° to the longitudinal axis (42) of the casting, wherein at least two core elements (18, 38, 40) are provided, which are located one inside the other and are positioned in the impression (12) of the drag (16) and which respectively have a parting plane (44), wherein the parting plane of a core element is understood as meaning a planar end face of the core element that is in the parting plane of the moulding flask during the casting, wherein the parting plane of the respective core element is arranged at a predetermined angle of 90° to the longitudinal axis (42) of the casting, wherein at least one of the core elements (18, 38) reproduces at least part of the outer geometry of the casting, wherein the core elements (18, 40) are reproduced or received completely in the drag (16) of the moulding flask (10), and wherein the form of the casting to be produced is formed completely in the drag.
2. Method according to Claim 1,
   characterized
   in that the first core element (18, 38) is a water-jacket core element (38).
3. Method according to at least one of Claims 1 and 2,
   characterized
   in that the second core element (18, 40) is an oil core element (40) .

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