EP3771506B1 - Casting method with a shaping contour for producing a core, component and system for producing a component - Google Patents

Description

The present property right relates to a casting process in which a shaping contour is used to produce a core. The property right also relates to a corresponding component and a system for its production.

Casting processes for producing components with cavities are known from the prior art, in which cores are produced from salt or from other inorganic molding materials.

On the one hand, the cores are subject to deformation during cooling, which leads to a deviation of the geometry from the target geometry. On the other hand, there are geometric restrictions resulting from the mechanical properties of the core materials or core structures. For example, achievable ratios of cross-section to length in the prior art limited. These methods are therefore only conditionally suitable for filigree structures. Accordingly, the components known from the prior art also have corresponding shortcomings or can only be produced with relatively great effort.

The pamphlet EP 2 949 413 A1 shows a casting method comprising casting a metal heat exchanger by a die casting process onto a core, the core having a salt component soluble in a water solvent and a metal component not soluble in the solvent. The soluble salt core component is integrally cast onto the surface of the metal core component to form a desired shape. During casting, the insoluble core component and the soluble core component are in direct contact with the molten metal and remain in the solidified metal casting. The method further includes dissolving the soluble salt portion with the water solvent to form one or more cavities and/or channels of the desired shape in the heat exchanger casting.

The pamphlet DE 10 2010 051 356 A1 shows a method for producing an insert for producing at least one cavity in a cast component, the insert having at least one salt core and a metallic molded element at least partially surrounding the salt core. In the method, the metallic mold element and a salt layer forming the salt core are first arranged one above and/or next to one another. Subsequently, the metallic shaped element is subjected to a forming force, by which the metallic shaped element is plastically deformed to form a profile. As a result of the plastic deformation of the shaped element, the salt layer is deformed and/or compressed to form a salt core that forms the cavity in the cast component.

The pamphlet U.S.A. 4,574,865 Figure 12 shows a hollow metal shell of a cast finned recuperator tube being cast with preformed inner fins and outer fins connected thereto. A sand core is formed around the preformed inner ribs with portions of the ribs protruding from the sand core, and a sand mold becomes a cavity for receiving the sand core molded with the preformed outer ribs embedded in the sand mold with portions of the ribs protruding therefrom into the cavity. The sand core is placed in the sand mold at a distance from it, so that a free space is created between the sand core and the sand mold, into which the sections of the inner ribs and the outer ribs extend. Molten metal is poured into the gap and solidifies on cooling to form the shell with the inner fins and outer fins fused integrally thereto.

Against this background, it is the object of the present invention to propose an improved casting method and a corresponding component, as a result of which the problems occurring in the prior art can be at least partially eliminated. Preferably, complex hollow structures should also be made possible in a cost-effective manner.

This is achieved by a method according to independent claim 1. Likewise, the advantages according to the invention are realized by a component according to claim 10 and by a system for producing a component according to claim 14. Advantageous configurations of the method, the component and the system result from the dependent claims and from the following description and the figures.

• Herstellen eines Profils mit Rippen, wobei das Profil als Hohlzylinder ausgebildet ist und die Rippen sich außen an einer Mantelfläche des Hohlzylinders erstrecken und in axialer Richtung verlaufen und wobei das Profil mitsamt den Rippen durch Strangpressen hergestellt wird,
• Anordnen des Profils in einem Kerngusswerkzeug, sodass sich die Rippen in einem Zwischenraum zwischen Profil und Kerngusswerkzeug erstrecken,
• Herstellen eines Kerns in dem Zwischenraum zwischen Profil und Kerngusswerkzeug,
• Entnehmen des Profils mit dem daran angeordneten Kern aus dem
• Kerngusswerkzeug,
• Anordnen des Profils mit dem Kern in einem Kerngusswerkzeug,
• Gießen eines Gussmantels, wobei der Gussmantel Kontakt zu dem Kern und zumindest abschnittsweise Kontakt zu zumindest einem Teil der Rippen hat,
• Entfernen des Kerns.

Accordingly, a method for producing a component with a cavity is proposed, which comprises at least the following steps:

• Production of a profile with ribs, the profile being designed as a hollow cylinder and the ribs extending on the outside of a lateral surface of the hollow cylinder and running in the axial direction, and the profile together with the ribs being produced by extrusion,
• Arranging the profile in a core casting tool so that the ribs extend in a space between the profile and the core casting tool,
• Making a core in the space between the profile and the core casting tool,
• Removing the profile with the core arranged on it from the
• core casting tool,
• arranging the profile with the core in a core casting tool,
• Casting a cast shell, the cast shell being in contact with the core and at least in sections with at least part of the ribs,
• removing the core.

An intermediate product is thus typically produced in the method, which comprises the profile with the ribs and the core arranged thereon. This is typically distinguished by advantageous mechanical properties, which, among other things, can enable the production of filigree structures, in which case complex post-processing or subsequent joining operations can be dispensed with. Furthermore, complex components can also be manufactured inexpensively.

For example, the steps are performed in the order shown above.

Between the ribs, the profile and the casting shell, where the core is located during casting, there are typically left several chambers belonging to the cavity of the component after the core has been removed.

In the process, profile is produced by extrusion. The profile is produced together with the ribs in an extrusion process.

The profile can be made of metal, in particular aluminum. But it can also be made of plastic.

In the process, the profile is designed as a hollow cylinder. The ribs then extend on the outside of a lateral surface of the hollow cylinder. The ribs run in the axial direction along the outside of the hollow cylinder. A A component with such a profile can then, in addition to the cavities formed by the chambers, also have one or more other cavities--in particular the additional cavity located inside the hollow cylinder.

Alternatively or in addition to what is described above, in possible embodiments the ribs can be shorter than an overall length of the profile and/or interrupted. This allows adjacent chambers to exist due to the discontinuities or the shorter design Passages be fluidly connected to each other. As will be explained later, such an embodiment can be particularly advantageous in the production of electric motors.

As mentioned, in the method the core can be arranged in particular on the outside of the profile. In the method it can be provided that a form fit is produced between the ribs and the core casting tool. In the method it is possible in particular for the ribs to protrude from the core. This can be achieved, for example, by the above-mentioned form fit between the ribs and the core casting tool, with those sections of the ribs that produce the form fit with the core casting tool being inaccessible to the core material. Sections of the ribs that protrude from the core can then produce a further positive fit with the cast shell, as a result of which an improved connection to the cast shell and thus a more robust component overall can be achieved.

The core can contain, for example, salt and/or sand and/or a temperature-stable molding compound. The core can be formed in particular from a molten salt.

The core can be produced in a casting process, for example in a low-pressure casting process. However, the production of the core is not limited to such methods. The profile can be heated and/or cooled during the process. For example, the profile can be heated before casting the core and/or the profile can be cooled during casting and/or after casting.

In the method, the core may include a gate. In possible implementations, the gate is removed prior to pouring the casting shell.

In the method, the cast jacket can be produced, for example, in a die-casting process. The cast casing can also be produced, for example, in a low-pressure casting process or in a gravity die casting process or in a sand casting process. The cast jacket can also be produced in an injection molding process.

In the method, the cast jacket can be made of metal, for example aluminum. However, the cast jacket can also be made of plastic, for example.

In the method, one or more cover plates can be provided on the cast jacket. For example, at least one cover plate can be cast together with the cast shell and thus represent part of the cast shell. The cast jacket can then have a cup shape. A further cover plate can then, for example, be added in a further process step after the cast jacket has been cast. In another embodiment, both cover plates can also be added later.

In the method, at least one contact opening can be provided in at least one of the cover plates. The at least one contacting opening can preferably be arranged in the radially exposed area of the cover plate, in which the cavity extending between the profile and the cast jacket extends. For example, a first contact opening can produce a fluidic connection to one of the chambers. A further contacting opening can produce a fluidic connection to a further chamber. Thus, the cavity can be contacted via the contacting opening or the contacting openings by a cooling medium, which can be supplied and discharged through the openings.

The invention also relates to a component with a cavity, which is produced by a method as described above. The component includes a profile with a plurality of ribs and a cast casing. The cavity extends between the profile and cast jacket and the ribs extend into the cavity. The cast jacket is connected to the ribs. The cavity can thus be separated into several chambers by the ribs, the chambers being able to be connected to one another, for example, by interruptions in the ribs or by the ribs being shortened on one or both sides, so that a cooling medium can flow between the various chambers. In particular, the ribs can be shortened at alternately opposite ends or in the vicinity of these Ends be interrupted so that a passage from one chamber to the next is provided alternately at opposite ends of the component and a substantially meandering gap is formed.

In the case of the component, there can be a form fit between the ribs and the cast casing.

The profile and the cast casing can be formed, for example, from a metal, such as aluminum, or from plastic.

In the case of the component, the cast jacket can have a hollow-cylindrical section. The cast shell may include a cast cover plate. The cast shell may alternatively or additionally include an attached cover plate.

One or more contact openings for a cooling medium can be arranged in at least one of the cover plates of the cast casing. For example, the one or more contacting openings can be arranged in such a way that they enable access to the cavity, in particular one of the chambers, between the profile and the cast casing.

The component can represent a component of an electric motor. In particular, it can be a motor housing. In particular, it can be a motor housing of a medium-cooled electric motor. The embodiment with the fluidically connected chambers and the one or more contacting openings is particularly suitable for this.

However, the component can also be a structural component with a cavity. A support structure can be present, which can be represented in particular by the profile with the ribs.

The invention also relates to a system for manufacturing a component with a cavity. In particular, it can be a system for producing the component described above or a system for carrying out the method described above.

The system includes a profile with ribs and a core casting tool for receiving the profile with the ribs, wherein the core casting tool can have one or more rib receiving recesses. At least some of the ribs can be partially inserted into the rib receiving recesses, so that a form fit can be produced between the core casting tool and the inserted ribs. An intermediate space between the profile and the core casting tool—in which the non-inserted sections of the ribs and possibly non-inserted ribs also extend—remains free. This space can then be filled with the core material. The core material can then fill the gaps left between the ribs.

The system can also include a casting tool, which is set up to receive the profile with the ribs and a core arranged thereon.

It should be emphasized that features that are only described here in connection with the method can also be claimed for the component and the system and vice versa.

The invention is explained in more detail below with reference to figures.

Figuren 1a, b

ein Profil mit Rippen, in einer perspektivischen Ansicht (a) und einer Seitenansicht (b),

Figur 2

ein Gusswerkzeug in geöffnetem Zustand mit teilweise eingesetztem Profil und in einer vergrößerten Ansicht eine Darstellung eines Formschlusses des Gusswerkzeugs mit dem Profil,

Figur 3

das mit Profil mit gegossenem Kern,

Figur 4a, b

eine perspektivische Ansicht eines Gussteils vor dem Entkernen, umfassend das Profil, einen Gussmantel (a) und den Kern, sowie eine Schnittansicht desselben Gussteils (b),

Figuren 5a-c

das als Motorgehäuse ausgebildete Gussteil nach dem Entkernen, von zwei entgegengesetzten Seiten (a, b) sowie in einer vergrößerten Ansicht (c),

Figur 6a

ein komplex geformtes Profil als Stützstruktur für ein Strukturbauteil,

Figur 6b

das Profil aus Figur 6a mit daran angeordnetem Kern,

Figur 6c

das entkernte Strukturbauteil, das Profil aus Figuren 6a und b umfassend, sowie einen gegossenem Gussmantel.

show in it

Figures 1a, b

a profile with ribs, in a perspective view (a) and a side view (b),

figure 2

a casting tool in the open state with a partially inserted profile and an enlarged view of a form fit of the casting tool with the profile,

figure 3

the one with cast core profile,

Figure 4a, b

a perspective view of a casting before core removal, comprising the profile, a casting jacket (a) and the core, and a sectional view of the same casting (b),

Figures 5a-c

the cast part designed as a motor housing after core removal, from two opposite sides (a, b) and in an enlarged view (c),

Figure 6a

a complex shaped profile as a support structure for a structural component,

Figure 6b

the profile Figure 6a with attached core,

Figure 6c

the gutted structural component, the profile Figures 6a and b comprising, and a cast iron shell.

Figures 1a and b show different views of a profile 1 with ribs 2, which is produced in an extrusion process. The profile 1 is produced in the extrusion process together with the ribs 2, as a result of which production costs are kept low. Figure 1a shows a perspective view and Figure 1b a side view. The profile 1 has a hollow-cylindrical shape, with the ribs 2 being arranged on the outside of a lateral surface of the hollow cylinder and extending in the axial direction. As in both Figures 1a and 1b As can be seen, the ribs do not extend over the entire length of the hollow cylinder, but are shortened at the ends, with adjacent ribs being shortened at opposite ends, so that a meandering intermediate space is formed.

figure 2 shows how the profile looks Figure 1a and Figure 1b is used in a core casting tool 3, which comprises two tool halves which can be joined together in such a way that the profile 1 with the ribs 2 can be arranged in a cavity of the core casting tool 3. A surface of the core casting tool that delimits the cavity has rib receiving recesses 4 into which the ribs 2 of the profile used can be inserted. As in the right in the figure 2 As can be seen in the enlarged view shown, the ribs 2 form a form fit 10 with the rib receiving recesses 4. A gap 11' between the profile 1 and the core casting tool 3 is delimited on the inside by the hollow cylindrical inner part of the profile 1, on the outside by the core casting tool 3 and also laterally bounded by two of the ribs 2. The core can then be produced in this intermediate space 11' by introducing a core material, in particular a molten salt, there.

figure 3 now an intermediate product comprising the profile and the core 5 arranged thereon. The core 5 extends on the outside of the essentially cylindrical profile 1 and has the ribs 2 passing through it. The core 5 has a chamfer 6 which extends axially on one side of the cylindrical profile 1 . Sections of the ribs 2 lying radially on the outside protrude radially from the core 5 . Gate 6 can be removed in one step of the process.

Figure 4a now shows the intermediate product figure 3 , with the profile 1 and the salt core 5 arranged thereon, wherein the gate 6 has been removed and a cast casting jacket is also arranged on the outside of the intermediate product. To produce the cast casing 7, the intermediate product is placed in a casting tool and the cast casing 7 is then produced in a pressure casting process, a low-pressure casting process, a gravity die casting process, a sand casting process or an injection molding process. The cast jacket 7 encloses the intermediate product and is also essentially cylindrical. It also includes a cover plate 8, which was cast in one go. The cast casing 7 engages in the ribs 2 in a form-fitting manner. This is made possible by the fact that these, as described above, protrude a little from the core material and thus a form-fitting connection can be produced for the protruding section.

Figure 4b shows a section through the in Figure 4a arrangement shown. Here it can be seen again that some of the ribs 2 do not extend over the entire length of the profile 1 or the cast casing 7 .

Figures 5a to c show the component from the previous figures, wherein the core 5 has been removed. The core can be removed in particular by dissolving it out. The component is a housing of an electric motor, with a cavity 11 lying between the profile 1 and the cast casing 7, which is divided into several chambers by the ribs 2 which are connected to one another due to the shortened ribs 2 at the ends of the component. To cool the electric motor, the cavity 11 can be acted upon by a cooling medium which can flow through the cavity, following its meandering shape. The housing of the electric motor is made of metal, in particular aluminum.

Figure 5b shows a rear side of the component, where a cover plate 8 of the cast jacket 7 can be seen. In a radially outer area, at the height of the cavity 11, it has contacting openings 9, through which the cavity 11 can be contacted with the cooling medium. On the opposite side can be done in one step. A cover plate can also be arranged during the process; this can be attached, for example.

Figure 5c shows the form fit 10 'between the ribs 2 and the cast jacket 7 in an enlarged view.

Figures 6a to c refer to a structural component that can be made of plastic, for example. The production of the structural component is analogous to the production of the engine housing, which was described above.

Figure 6a shows a profile 1 with external ribs 2. The profile is cylindrical and the ribs 2 are arranged on its outside thereof.

Figure 6b shows the profile 1 with the core 5 arranged on the outside. This again represents the intermediate product known from the manufacturing process of the electric motor.

Figure 6c finally shows the finished structural component, with a cavity 11 which extends between the cylindrical part of the profile 1, the cast casing 7 and the ribs 2.

Reference List

1

profile

2

rib

3

core casting tool

4

rib receiving recess

5

core

6

bleed

7

cast jacket

8th

cover plate

9

contact opening

10,10'

form fit

11, 11'

cavity, space

Claims (14)

1. A method for producing a piece part having a cavity (11), comprising at least the following steps:

   - producing a profile (1) having ribs (2),
   the profile (1) being designed as a hollow cylinder and the ribs (2) extending on the outside of a shell surface of the hollow cylinder and running in the axial direction and the profile together with the ribs being produced by extrusion,

   - arranging the profile (1) in a core casting tool (3) so that the ribs (2) extend in an intermediate space (11') between the profile (1) and the core casting tool (3),

   - producing a core (5) in the intermediate space (11') between the profile (1) and the core casting tool (3),

   - removing the profile (1) having the core (5) arranged thereon from the core casting tool (3),

   - arranging the profile (1) having the core (5) in a casting tool,

   - casting a cast shell (7), the cast shell (7) being in contact with the core (5) and at least in sections has contact with at least some of the ribs (2),

   - removing the core (5).
2. The method according to claim 1, wherein a form fit (10') is produced between the ribs (2) and the cast shell (7).
3. The method according to claim 1 or 2, wherein the profile (1) is made of metal.
4. The method according to any one of the preceding claims, wherein the ribs (2) do not extend over an entire length of the profile (1) and/or are interrupted.
5. The method according to any one of the preceding claims, wherein a form fit (10) is produced between the ribs (2) and the core casting tool (3) and/or wherein the ribs (2) protrude from the core (5).
6. The method according to any one of the preceding claims, wherein the core (5) is arranged on the outside of the profile and/or wherein the core (5) contains salt and/or sand and/or a temperature-stable molding compound, in particular is formed from molten salt.
7. The method according to any one of the preceding claims, wherein the core is produced in a casting process, in particular a low-pressure casting process, and/or wherein the profile (1) is heated before casting the core (5) and/or the profile (1) is cooled during or after casting.
8. The method according to any one of the preceding claims, wherein the core (5) comprises a gate (6) which is preferably removed before casting the cast shell and/or wherein the cast shell (7) is produced in a die casting process or a low pressure casting process or a permanent mold gravity casting process or a sand casting process or in an injection molding process.
9. The method according to any one of the preceding claims, wherein the cast shell (7) is produced from aluminum or plastic and/or wherein a cover plate (8) of the cast shell (7) is also cast.
10. A piece part having a cavity (11), produced in a method according to any one of the preceding claims, comprising a profile (1) having a plurality of ribs (2) and a cast shell (7),
    the profile (1) being designed as a hollow cylinder and the ribs (2) extending on the outside of a shell surface of the hollow cylinder and running in the axial direction and the cavity (11) extending between the profile (1) and the cast shell (7) and the ribs (2) extending in the cavity (11), and the cast shell (7) being connected to the ribs (2), which is preferably a component, in particular a motor housing, of a media-cooled electric motor or a structural component having a cavity and a support structure.
11. The piece part according to claim 10, wherein there is a form fit (10') between the ribs (2) and the cast shell (7) and/or wherein the profile (1) and the cast shell (7) are formed from aluminum or plastic.
12. The piece part according to any one of claims 10 or 11, wherein adjacent ribs (2) are shortened or interrupted at opposite ends such that a meandering intermediate space is formed between the ribs (2).
13. The piece part according to any one of claims 10 to 12, wherein the cast shell (7) has a hollow-cylindrical section and/or a cover plate (8), wherein contact openings for a cooling medium are preferably arranged in the cover plate of the cast shell (7).
14. A system for producing the piece part according to any one of claims 10 to 13, comprising

    the profile (1) having the ribs (2),

    a core casting tool (3) for receiving the profile (1) having the ribs (2), the core casting tool (3) having one or more rib receiving recesses (4) into which at least part of the ribs (2) can be inserted, so that a form fit (10) can be produced between the core casting tool (3) and the ribs (2), and an intermediate space remaining free between the profile (1) and the core casting tool (3), furthermore preferably comprising a casting tool set up for receiving the profile (1) having the ribs (2) and a core (5) arranged thereon.

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