EP3401037B1 - Mold for producing a casting core - Google Patents

Description

The invention relates to a mold for producing a casting core, which maps coolant channels and coolant inflows and outflows of a cooling jacket of an electric motor.

The efficiency of modern electric motors, and especially of electric motors that serve to drive vehicles, depends heavily on the cooling of the electric motor. Often, such electric motors are therefore provided with a cooling jacket with coolant channels running therein, which from a cooling fluid, for. B. water.

Because of the complexity of the shape of the coolant channels, the z. B. may be meandering, the production of the cooling jacket in a casting process may be useful. However, this type of production requires a suitable casting core, which must be placed within the casting mold in order to map the coolant channels and also the necessary coolant inflows and outflows in terms of casting technology. Depending on the complexity of the coolant channels, the casting core required for this is also designed to be relatively complex.

The JP 2015 044217 A discloses a mold for producing a casting core with a core mold space that can be filled with core material. Eight molded shells can be moved between a radially outer position with a closed outer circular shape and an inwardly displaced position. For this purpose, the first four molded shells, in each case two of the four molded shells lying opposite each other, and subsequently the remaining four second molded shells each arranged between the first molded shells, wherein two of the four molded shells also lying opposite each other, are displaced radially inward into the gap which arises. A respective demolding technique with guides, which are fastened to the mold shells, is provided for demolding the casting core. Other forms for producing a casting core are from the US 2008/0274289 A1 as well as the JP H07 266000 A known.

The aim is therefore to enable the molding of a casting core, which maps the coolant channels and coolant inflows and outflows of the cooling jacket of an electric motor, and which can be removed from the mold easily and non-destructively after molding.

• zwei erste Formschalen und zwei zweite Formschalen, die alle vier gemeinsam die Innenwand des Kernformraums begrenzen, wobei die zweiten Formschalen jeweils zwischen den ersten Formschalen angeordnet sind,
• ein erster Entformmechanismus, welcher zwischen den ersten Formschalen angeordnet und dazu ausgebildet ist, diese aufeinander zu zu bewegen, wobei die erste Entformmechanik einen in Richtung der Achse längsbeweglich angeordneten Schalenträger mit zwei daran angeordneten Führungen umfasst, wobei auf der einen Führung die eine, und auf der anderen Führung die andere der beiden ersten Formschalen verschieblich gelagert ist, und wobei die Längsrichtungen der zwei Führungen zueinander konvergieren,
• ein zweiter Entformmechanismus, welcher zwischen den zweiten Formschalen angeordnet und dazu ausgebildet ist, diese aufeinander zu zu bewegen, wobei die zweite Entformmechanik einen in Richtung der Achse längsbeweglich angeordneten Schalenträger mit zwei daran angeordneten Führungen umfasst, wobei auf der einen Führung die eine, und auf der anderen Führung die andere der beiden zweiten Formschalen verschieblich gelagert ist, und wobei die Längsrichtungen der zwei Führungen zueinander konvergieren,

wobei einer der Schalenträger einschließlich der an ihm angeordneten Führungen einteilig ausgebildet ist, und der andere Schalenträger einschließlich der an ihm angeordneten Führungen zweiteilig aus zwei in Richtung der Achse hintereinander angeordneten Trägerabschnitten ausgebildet ist.A mold is therefore proposed for producing a casting core, which depicts coolant channels and coolant inflows and outflows of a cooling jacket of an electric motor using a casting technique, with a core mold space which can be filled with core material and which is essentially cylindrical around a central axis. The outer wall of the core molding space is formed by an outer shape, and the inner wall by an inner shape which is completely surrounded by the outer shape. Components of the inner shape are:

• two first molded shells and two second molded shells, all of which together delimit the inner wall of the core molding space, the second molded shells each being arranged between the first molded shells,
• a first demoulding mechanism which is arranged between the first mold shells and is designed to move them towards one another, the first demoulding mechanism comprising a shell carrier which is arranged to be longitudinally movable in the direction of the axis and has two guides arranged thereon, the one, and on the one guide the other guide, the other of the first two molded shells is slidably mounted, and the longitudinal directions of the two guides converge towards one another,
• a second demoulding mechanism, which is arranged between the second mold shells and is designed to move them towards one another, the second demoulding mechanism comprising a shell carrier which is arranged to be longitudinally movable in the direction of the axis and has two guides arranged thereon, the one and the one guide the other guide, the other of the two second molded shells is displaceably mounted, and the longitudinal directions of the two guides converge towards one another,

one of the shell carriers including the guides arranged on it being formed in one piece, and the other shell carrier including the guides arranged on it being formed in two parts from two carrier sections arranged one behind the other in the direction of the axis.

With such a shape, complexly designed, cylindrical casting cores can be produced, which can map the coolant channels and coolant inflows and outflows of the cooling jacket of an electric motor. Such a cooling jacket typically has coolant channels shaped in a meandering manner in its interior, which combine to form an essentially cylindrical shape. Accordingly, the core mold space filled with core material during the production of the casting core is primarily determined by an outer shape and an inner shape. The outer shape forms the outer wall of the core molding space, and the inner shape forms the inner wall of the core molding space. The cylindrical inner shape is enclosed over its entire circumference by the cylindrical outer shape.

Components of the inner mold are two first mold shells and two second mold shells, with all four mold shells jointly shaping and delimiting the inner wall of the core mold space, and wherein the second mold shells are each movably arranged between the first mold shells.

Part of the inner mold is a first demolding mechanism, which is arranged between the first mold shells and designed to move them towards one another. Also part of the inner mold is a second demolding mechanism, which is arranged between the second mold shells and is designed to move these second mold shells toward one another.

It is therefore a movement inward towards the longitudinal axis of the inner mold achieved by the two demolding mechanisms, by means of which the core mold space is opened or released during the demolding.

With regard to the first demolding mechanism, it is proposed that this one in the direction the central axis comprises longitudinally movably arranged shell supports with two guides arranged thereon, the one of the first and the other of the two first molded shells being displaceably mounted on one guide, and the longitudinal directions of these two guides converge to one another. Converging means that the virtual axes of the two longitudinal directions meet at a point outside the shell carrier.

With regard to the second demoulding mechanism, it is proposed that it comprise a shell support arranged to be longitudinally movable in the direction of the central axis, with two guides arranged thereon, the one of the two and the other of the two second shell shells being displaceably mounted on one guide, and wherein the longitudinal directions of these two guides converge to one another. Converging means that the virtual axes of the two longitudinal directions meet at a point outside the shell carrier.

Preferably, the two shell supports are longitudinally movable in the direction of the central axis, for. B. by the one shell carrier is slidably disposed in the other shell carrier.

In order to achieve complete demolding on the inner mold by means of a single, continuous drive movement, the guides on one shell carrier and the guides on the other shell carrier are each aligned such that they converge in the same direction or both diverge in the opposite direction.

So that at first only the pair of first molded shells and only later the pair of second molded shells retract inwards through a single, continuous drive movement, stops are formed on the shell supports, which limit the mutual longitudinal mobility of the shell carriers at least in the opposite direction to the convergence of the guides.

In order to be able to build the two mechanisms that retract the mold shell pairs for demolding compactly and space-savingly into one another, one of the shell carriers including the guides arranged on them is formed in one piece, whereas the other shell carrier including the guides arranged on it is made of two parts in the direction of the central axis formed one behind the other carrier sections. In this case, the division of the guide arranged on the other shell carrier is such that guide sections are present on each of the carrier sections, the guide sections being aligned with one another.

The one-piece shell support is preferably divided into two segments by a longitudinal slot, and the segments are connected to one another only by means of webs.

According to a further embodiment of the shape, one of the shell carriers has a frustoconical basic shape, and the other shell carrier has a basic shape comprising a cylinder and arms projecting radially from the cylinder. The cylinder is longitudinally guided in the other, ie the frustoconical shell support. This contributes to a nested and thus compact structure of the two mechanisms, which pull the mold shell pairs back during demolding.

According to a further embodiment of the form, the guides have a T-shaped cross section and they engage in grooves provided with corresponding undercuts on the inner sides of the respective shaped shells.

Finally, it is proposed that the mutually facing inner sides of the first mold shells forming the first pair of mold shells successively each have an end section, a middle section and a further end section, and that the inner sides spring back on the middle section in comparison to the two end sections to form a recess.

Fig. 1

in perspektivischer Darstellung nur das mittels der hier beschriebenen Form herstellbare Produkt, nämlich ein Gießkern, der Kühlmittelkanäle sowie Kühlmittelzu- und -abflüsse des Kühlmantels eines Elektromotors gießtechnisch abbildet;

Fig. 2

in perspektivischer Darstellung die komplette Form zum Herstellen des in Fig. 1 illustrierten Gießkerns;

Fig. 3

ebenfalls die Form, jedoch im Vergleich zu Fig. 2 ohne die Bestandteile der Außenform;

Fig. 4

eine Stirnansicht auf die Formschalenpaare der Innenform, und zwar in der Betriebsstellung maximaler Entformung;

Fig. 4a

den Bereich IV der Fig. 4 in einer vergrößerten Darstellung;

Fig. 5

in perspektivischer Einzeldarstellung nur einen ersten Schalenträger der Innenform;

Fig. 6

in perspektivischer Einzeldarstellung nur einen zweiten Schalenträger der Innenform;

Fig. 7

die beiden ineinandergesetzten Schalenträger, und zwar in der Formstellung;

Fig. 8

im rechten Bildteil die beiden ineinandergesetzten Schalenträger in der Betriebsstellung maximaler Entformung;

Fig. 9a

die Form in einer Betriebsstellung, in der nur die beiden zweiten Formschalen entformt sind;

Fig. 9b

dieselben Gegenstände in einer fortgeschrittenen Betriebsstellung, in der auch die beiden ersten Formschalen entformt sind, und

Fig. 10

eine Stirnansicht auf alle Formschalen in der Betriebsstellung nach Fig. 9b.

Further details and advantages will become apparent from the following description of a mold for producing a casting core. For this purpose, reference is made to the drawings. Show in it

Fig. 1

in a perspective view, only the product that can be produced by means of the mold described here, namely a casting core, which depicts coolant channels and coolant inflows and outflows of the cooling jacket of an electric motor in terms of casting technology;

Fig. 2

in perspective the complete form for producing the in Fig. 1 illustrated casting core;

Fig. 3

also the shape, but compared to Fig. 2 without the components of the outer shape;

Fig. 4

an end view of the mold shell pairs of the inner mold, in the operating position of maximum demolding;

Fig. 4a

the area IV of the Fig. 4 in an enlarged view;

Fig. 5

in perspective individual representation only a first shell support of the inner shape;

Fig. 6

in perspective individual representation only a second shell support of the inner shape;

Fig. 7

the two nested shell supports, in the form position;

Fig. 8

in the right part of the picture the two nesting shell supports in the operating position of maximum demolding;

Fig. 9a

the mold in an operating position in which only the two second mold shells are removed;

Fig. 9b

the same objects in an advanced operating position, in which the first two molded shells are removed, and

Fig. 10

an end view of all molded shells in the operating position Fig. 9b ,

In Fig. 1 is shown a casting core 1 made of casting sand. The casting core 1 is used to cast coolant channels 2, a coolant inflow 3 and a coolant outflow 4 of a cooling jacket of an electric motor. If the casting core 1 is therefore placed within a casting mold, it defines those areas where the coolant channels 2, the coolant inflow 3 and the coolant outflow 4 are located after the casting has been completed.

Because of the complexity of the shape of the coolant channels 2, which according to Fig. 1 are meandering, the production of the cooling jacket used for the electric motor in a casting process is useful.

In the following, a form is proposed with which the casting core 1 can be produced, the main aim being good and non-destructive demolding.

In Fig. 2 the form designed according to the invention is reproduced in its entirety. It consists of an outer shape 9 and an inner shape 10, both of which are arranged around a central axis A. The core mold space, whose shape in Fig. 1 is reproduced on the basis of the object produced (casting core), is accordingly also essentially cylindrical. The outer wall of the core mold space is formed by the outer mold 9, and the inner wall of the core mold space by the inner mold 10. The core material, for. B. pouring a pouring sand into the core mold space, in which the pouring sand then solidifies to the pouring core.

According to Fig. 2 the outer shape 9 is composed of a total of four segments, of which each segment extends approximately over a quarter circle. During the demolding, the four segments are moved radially outward, with the result that the cast core 1 produced is then exposed on its outside.

The internal mold 10, on the other hand, cannot be removed from the mold by a simple radial movement of individual segments, since these would collide with one another when they moved inwards towards the longitudinal axis A.

Although according to Fig. 4 also part of the inner mold 10 four segments, which add up to a cylinder and form the inner wall of the core mold space on their outer sides. However, the four segments are not of uniform size and shape. Instead, two segments are designed as first molded shells 11 and two further segments as second molded shells 13. All four molded shells 11, 13 jointly delimit the inner wall of the core molding space, the second molded shells 13 each being arranged between the first molded shells 11. Since the second molded shells 13 are each arranged between the first molded shells 11, the two second molded shells 13 can be moved inwards towards the central axis A of the inner mold 10 without abutting the two first molded shells 11.

In Fig. 4 and Fig. 4a the consequence of this different design is shown on the one hand of the molded shells 11 and on the other hand of the molded shells 13: the two second molded shells 13 have been moved radially inwards here, but are still located between the first molded shells 11. At the same time, the first molded shells 11 are located where in according to the operating position Fig. 4 the circumferential edges of the second molded shells 13 are each provided with a recess 17.

According to Fig. 4a The recesses 17 in the first molded shells 11 are achieved in that the mutually facing inner sides of the two first molded shells 11 each have an end section 18a, a middle section 19 and a further end section 18b in succession. The inner sides of the first molded shells 11 spring back on the middle section 19 in comparison to the two end sections 18a, 18b, each forming the recess 17. This is in Fig. 4a additionally illustrated by the fact that one of the two second molded shells 13 is also sketched in dashed lines.

Furthermore, the Figures 4 and 10 , which represent the mold shell pairs 11, 13 each in the operating position of maximum demolding, which recognize the different circumferential size of the mold shells 11 on the one hand and the mold shells 13 on the other hand. The first molded shells 11 each extend over a larger circumferential angle than the second molded shells 13. For example, the first molded shells 11 can each extend over a circumferential angle of 100 °, while the second molded shells 13 each only over a circumferential angle of 80 °.

Components of the inner mold 10 are also two demolding mechanisms by means of which the mold shells 11, 13 can be moved in the direction of the central axis A. A first demolding mechanism is arranged between the first mold shells 11 and designed to move these first mold shells 11 towards one another. Analogously, a second demolding mechanism is arranged between the second mold shells 13 and designed to move the second mold shells 13 towards one another.

In both cases, the mechanism is an oblique guidance of the two molded shells on a shell support. There are two shell carriers in total. Fig. 5 represents the first shell carrier 20, which is constructed here in two parts, and Fig. 6 the second shell support 30, which is designed in one piece here Fig. 7 shows the two shell supports 20, 30 in an assembled state. This is also the operating position during the molding process.

The first shell support 20 has a basic shape composed of a central cylinder 21 and four arms 22 projecting radially therefrom. The cylinder 21 is of such a size that it can slide essentially without play in a cylindrical opening 24 with which the second shell support 30 is provided.

Guides 25A, 25B are formed on the outer ends of the four arms 22. The guides 25A, 25B are each of a T-shaped cross section and designed to be in undercut grooves 26 slide on the inner sides of the first molded shells 11 without play.

So that the two shell supports 20, 30, as in Fig. 7 reproduced, can be assembled into one another, the first shell support 20 is formed in two parts from two support sections 20A, 20B arranged one behind the other in the direction of the axis A. The carrier section 20A includes the cylinder 21 and the two radially projecting arms on which the two guide sections 25A are located. The other, comparably shorter support section 20B comprises the other two arms 22, at the ends of which the two guide sections 25B are formed.

The design of the first shell carrier 20 is such that the guide sections 25A and 25B arranged on the same side of the axis A are aligned with one another and therefore together form a guide 25 which is interrupted in a central section. The guide 25 composed of the guide portions 25A and 25B on one side of the axis A, and the guide 25 composed of the guide portions 25A and 25B on the other side of the axis A are inclined to the axis A, respectively, and they converge toward each other as in Fig. 5 the dashed line representing the direction of the guide 25 illustrates.

The in Fig. 6 reproduced second shell support 30 has a frustoconical basic shape. On its sides opposite one another with respect to the central axis A, guides 35 of T-shaped cross section are formed in each case, which engage in grooves 36 on the second molded shells 13 in a slidable manner. For this purpose, the grooves 36 on the second molded shells 13 are provided with corresponding undercuts.

The frustoconical shell carrier 30 has the cylindrical opening 24 in the center, in which the cylinder 21 of the other shell carrier 20 is mounted so as to be longitudinally movable.

The shell support 30 is formed in one piece and is divided by a longitudinal slot 38, which provides space for the arms 22, into two essentially semi-conical segments, these segments being connected to one another only via two webs 39. At the end of each longitudinal slot 38 there is a stop 37. The corresponding counter stop 27 is located on the two longer arms 22 of the first shell carrier 20. The stops 37 formed on the shell carrier 30, together with the stops 27 formed on the shell carrier 20, limit the mutual longitudinal mobility the Shell carrier 30, 20 in the direction opposite to the convergence of the guides 35, 25.

The Figures 9a and 9b illustrate the operation of the two demolding mechanisms in two different operating positions:
In the operating position according to Fig. 9a is moved inward by a longitudinal movement of the second shell support 30 in the direction of the central axis A, each of the two second molded shells 13. The first two molded shells 11 do not yet perform an inward movement at this time.

In the operating position after Fig. 9b the second shell support 30 is moved further along the axis A, the stop 37 already abutting against the stop 27. As soon as these stops collide, the shell carrier 20 is carried along by the longitudinal movement of the shell carrier 30, so that from now on both shell carriers 20, 30 move together in the direction of the central axis A. As soon as the first shell carrier 20 also moves in the longitudinal direction, it moves the first molded shells 11 inwards via its guides 25, so that these peripheral regions are also removed from the mold.

All in all, the demolding takes place in two stages (first the second molded shells 13, then only the first molded shells 11), but by means of a single, preferably continuously, drive movement. This drive movement is achieved by a continuous longitudinal movement of the second shell carrier 30, which automatically takes along the first shell carrier 20 after a certain longitudinal path.

Materials for the inner mold 10 can be plastic, metal or wood.

Suitable as the core material of the casting core 1 are sand or free-flowing oxidic substances or mixtures of substances which contain inorganic or organic binders, these substances or mixtures of substances hardening either thermally and / or chemically.

LIST OF REFERENCE NUMBERS

1

casting core

2

Coolant channel

3

coolant supply

4

Coolant outflow

9

external form

10

interior shape

11

first molded shell

13

second molded shell

17

recess

18a

end

18b

end

19

midsection

20

first shell carrier

20A

support section

20B

support section

21

cylinder

22

poor

24

opening

25

guide

25A

guide section

25B

guide section

26

groove

27

attack

30

second shell support

35

guide

36

groove

37

attack

38

longitudinal slot

39

web

A

central axis, longitudinal axis

Claims (9)

1. Mould for producing a casting core (1), which illustrates coolant channels (2) as well as coolant inflows and outflows (3, 4) of a cooling jacket of an electric motor using casting technology, with a core box space to be filled with core material, which is designed substantially cylindrically around a central axis (A), and the external wall of which is formed by an external mould (9) and its internal wall by an internal mould (10) completely enclosed by the external mould, wherein components of the internal mould (10) are:

   - two first mould shells (11) and two second mould shells (13), all four of which together delimit the internal wall of the core box space, wherein the second mould shells (13) are each arranged between the first mould shells (11),

   - a first demoulding mechanism, which is arranged between the first mould shells (11) and is formed for moving these towards each other, wherein the first demoulding mechanism comprises a shell support (20) that is longitudinally moveable in the direction of the axis (A), with two guides (25) arranged on the same, wherein one of these is displaceably mounted in one guide, and the other one of the two first mould shells (11) on the other guide, and wherein the longitudinal directions of the two guides (25) converge towards each other,

   - a second demoulding mechanism, which is arranged between the second mould shells (13) and is formed for moving these towards each other, wherein the second demoulding mechanism comprises a shell support (30) that is longitudinally moveable in the direction of the axis (A), with two guides (35) arranged on the same, wherein one of these is displaceably mounted in one guide, and the other one of the two second mould shells (13) on the other guide, and wherein the longitudinal directions of the two guides (35) converge towards each other,

   wherein one of the shell supports (30) including the guides (35) arranged on the same is a one-piece design and the other shell support (20) including the guides (25) arranged on the same is a two-piece design consisting of two support sections (20A, 20B) arranged one behind the other in the direction of axis (A).
2. Mould according to claim 1, characterised in that the two shell supports (20, 30) are designed to be longitudinally moveable towards each other in the direction of axis (A).
3. Mould according to claim 2, characterised in that the guides (35) on the shell support (30) and the guides (25) on the other shell support (20) converge in the same direction.
4. Mould according to claim 2 or 3, characterised by shoulders (37, 27) formed on the shell supports (30, 20), which delimit the reciprocal longitudinal movability of the shell supports (30, 20) at least in the direction opposite the converging of the guides (35, 25).
5. Mould according to claim 1, characterised by a division of the guide (25) arranged on the other shell support (20) in such a way that guide sections (25A, 25B) are present on each of the support sections (20A, 20B), wherein the guide sections (25A) of one support section are flush with the guide sections (25B) of the other support section.
6. Mould according to claim 1 or 5, characterised in that the one-piece design shell support (30) is divided into two segments by a longitudinal slot (38), and in that the segments are connected to each other only via bridges (39).
7. Mould according to one of the claims 2-6, characterised in that one of the shell supports (30) has a frustoconical base shape, that the other shell support (20) has a base shape composed of a cylinder and arms radially projecting from the same, and that the cylinder is longitudinally held in the frustoconical shell support (30).
8. Mould according to one of the claims 2-7, characterised in that the guides (35, 25) have a T-shaped cross-section and engage with grooves (36, 26) of an undercut design on the insides of the respective mould shells (13 or 11).
9. Mould according to one of the preceding claims, characterised in that the internal sides of the two first mould shells (11) facing each other successively have one end section (18a), one middle section (19) and one further end section (18b) each, and that the internal sides recede back to the middle section (19) compared to the two end sections (18a, 18b) whilst forming a recess (17).

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