EP3570992A1

EP3570992A1 - Casting mould for casting complexly shaped cast parts and use of such a casting mould

Info

Publication number: EP3570992A1
Application number: EP18709763.9A
Authority: EP
Inventors: Gerald KLAUS; Dirk Schnubel; Carmen Schäfer; Christoph Tomczok; Tim Schneider; Steffen Spieß; Paulo Rossi
Original assignee: Nemak SAB de CV
Current assignee: Nemak SAB de CV
Priority date: 2017-01-17
Filing date: 2018-01-17
Publication date: 2019-11-27
Anticipated expiration: 2038-01-17
Also published as: CN110191773B; WO2018134672A1; EP3570992B1; PL3570992T3; JP2020505232A; BR112019013406A2; CN110191773A; US20190337047A1; RU2717755C1; MX2019008443A; US11014144B2; KR20190105611A; JP6858863B2; KR102178737B1; DE102017100805A1; ZA201904169B

Abstract

The present invention relates to a casting mould (1) for casting complexly shaped, large-volume cast parts (Z) from molten metal, wherein the casting mould (1) has a mould cavity (5), producing an impression of the cast parts (Z), and a feeding system for feeding into the mould cavity (5) the molten metal that is to be cast into the cast parts (Z), wherein the feeding system comprises a sprue (10), a runner (7), connected to the sprue, and a feeder system (8), which is connected to the runner (7), and wherein the casting mould cavity (5) is connected to the feeder system (8) or the runner (7) by way of links (9a, 9b), and relates to the use of such a casting mould (1). The casting mould (1) according to the invention reliably allows highly complexly shaped cast parts to be created even from alloys that can only be cast with difficulty, and unreliably with regard to the quality of the cast result, in the case of the conventional procedure. This is achieved by the runner (7) - seen in the direction of flow (S) of the molten metal flowing from the sprue (10) into the runner (7) while casting operation - being made to extend with a branch (18, 19) directed away from the sprue (10) along the feeder system (8) and with a directed-back branch (20), which adjoins the directed-away branch (18, 19), along the feeder system (8) in a direction opposite to the directed-away branch (18, 19), and by the feeder system (8) being connected both by the directed-away branch (18, 19) and by the directed-back branch (20) by means of two or more gates (21-24) arranged distributed along the respective branch (18, 19, 20).

Description

Casting mold for casting complex shaped castings and use of such a casting mold

The invention relates to a casting mold for casting complex-shaped, large-volume castings from a molten metal. Such molds typically include a casting mold-forming cavity and a supply system for feeding the casting to be cast to the casting

Molten metal in the mold cavity. The feed system comprises a sprue, a runner connected to the sprue, and a feeder system connected to the runner, wherein the

Casting mold cavity with the feeder system or the casting over

Connections is connected

Furthermore, the invention relates to a practical use of such a casting mold.

When feeding castings with casting molds of the type in question, the feeder system on the one hand serves to control the solidification direction of the cast melt, which is optimally directed towards the feeder. On the other hand, the volume of melt held in the feeder system compensates for the reduction in the specific volume of the poured melt during the liquid / solid phase transition. The feeder system is an additionally attached melt reservoir, from which melt can flow into the casting during cooling. A special challenge is the casting of modern ones

Cylinder crankcases and similar filigree castings

Light metal alloys that can develop high mechanical properties or high thermal stability. To such

Light metal alloys include, for example, hardenable AICu alloys.

The high property potential of such light metal alloys are in practice problems in the reliable casting technology production of high-quality castings on an industrial scale

across from. It is, for example, difficult to produce AICu alloys from complex molded castings that are free from voids and hot cracks. It has been found that the quality of the casting obtained depends crucially on the uniformity of the filling of the mold cavity and the homogeneity of the temperature distribution in the melt.

Mass accumulations are associated with alloys with a non-shelling, mushy and / or spongy solidification morphology

Avoid, as Einschlaglunker arise and the make-up is complicated by the flow of the melt within the solidifying casting itself.

From the prior art is a large number of proposals for

Molds known to meet these requirements.

Thus, from DE 42 44 789 A1 a mold for casting a

Cylinder crankcase for an internal combustion engine, in which two separate feed hoppers are provided, via which the melt is poured into the mold. From the filling funnels, the melt flows in each case via a run into the mold cavity delimited by the casting mold. The runners are guided by a crankcase block core. Of the Runners branch off drainage channels which lead to lower casting contours of the casting mold. The sprues are each aligned so that their mouths lie on a horizontal plane.

A low-pressure mold casting method for casting metal castings, such as cylinder heads or engine blocks of internal combustion engines, is known from DE 39 24 742 A1. The complexity of the castings to be cast with this method results from the fact that they have thinner walls in at least one area than in another area. In the known method, liquid metal is forced out of a melt container through a riser pipe into the mold by means of gas pressure. In this case, the mold is arranged so that in her the thicker walls of the casting are lying on top and thus far away from the sprue over which the

Metal enters the component imaging cavity of the mold.

At the same time, the liquid metal is directed at or near the downhole region of the mold into the sections which are the thinner ones

Form the wall of the mold. In this case, the liquid metal can be supplied via a bottom run at a plurality of gate points the down near the casting near the area of the mold and are introduced into the thinner wall of the casting forming portions of the mold cavity.

WO 2014/111573 A1 finally discloses a method for casting cast parts, in which a molten metal is poured off via a feeder or separate runners or casting channels into a mold cavity bounded by a casting mold and imaging the casting. The mold comprises moldings which determine the shape of the casting to be cast. The melt is conducted via at least two connections, at least one of which is formed as an additional, leading through one of the moldings and independent of the contour of the cast casting channel, in at least two sections of the mold cavity, which are assigned to different levels of casting to be cast , For the casting of castings of the type considered here are suitable

in particular casting molds, which are completely or partially formed as a core package. In such a core package, the mold is composed of a larger number of cores, which determine the inner and outer contour of the casting to be produced. The casting cores are usually made of a molding material or an easily destructible material as so-called "lost cores", which are destroyed during demolding of the casting. However, there are also known hybrid forms of core packages, in which, for example, the outer contour defining moldings are designed as reusable permanent mold parts, while the casting to be imaged inside recesses, cavities, channels, lines etc. are represented by lost cores.

Core-package casting molds of the type described above are mainly used in gravity casting or low-pressure casting, these methods may also include a rotation of the mold after its filling with the melt to an optimized solidification course and, consequently, an optimal texture of the casting achieve.

Against the background of the prior art explained above, the object of the invention was to provide a casting mold which reliably allows to produce highly complex shaped castings also from alloys which are difficult to achieve in conventional procedure and uncertain in the quality of the casting result let shed.

In addition, a particularly advantageous use of such a mold should be specified.

With regard to the casting mold, the invention has achieved this object in that such a casting mold according to claim 1 is formed. An inventively designed mold is particularly suitable for use in casting a cylinder crankcase for a

Internal combustion engine made of a light metal melt, in particular an AICu melt.

Advantageous embodiments of the invention are in the dependent

Claims are given below and will be like the general one

Invention idea explained in detail.

A casting mold according to the invention for casting complex-shaped, large-volume castings from a molten metal has a

A casting mold-forming cavity and a delivery system for supplying the molten metal to be cast to the casting into the mold cavity, the delivery system comprising a gate, a runner connected to the gate, and a feeder system connected to the runner, the casting cavity being connected to the runner

Feeder system or the casting run is connected via connections.

According to the invention - seen in the direction of flow of pouring in the casting from the sprue into the casting molten metal - the casting run with a branch directed away from the sprue along the feeder system and with a back-branch, which adjoins the branched branch, in the direction away branch of opposite direction along guided by the feeder system, wherein the feeder system is connected to both the wegfällig branch and with the back-branch over two or more along the respective branch distributed arranged gates.

With the design of a mold according to the invention, it is possible, the temperature of the provided in the feeder system and in the

Mold cavity guided melt to even out so that adjusts an equally uniform temperature distribution in the casting. This Even with difficult to pour molten metals, especially in difficult to cast light metal melts, such as AICu melts, after filling the mold to a uniform

Solidification course, during which also a uniform

Make-up from the feeder system is ensured. local

Temperature differences and a concomitant, the risk of cavitation with bringing non-uniform solidification in the various levels of the casting are avoided in this way. Instead, in the melt filled in a casting mold according to the invention, a solidification front is formed, which, starting from the point furthest away from the feeder system, continuously forms in the direction of the

Feeder system progresses.

It should be understood that the terms "uniform temperature distribution", "average temperature", "homogenization of temperature distribution", "equal temperatures", "uniform temperature" and the like used herein are to be understood in a technical sense, i. can be occupied within the technical possibilities with the usual tolerated by the expert tolerances.

The homogenization of the temperature of the mold cavity supplied melt stream is achieved according to the invention, that the supplied via the sprue melt stream is first performed in a leading away from the sprue "away branch" along the feeder system, while already provided on the along the wegreckten branch provided in the gate system runs and then in the opposite direction to the run away from the sprinkling branch, "directed back branch", is analogously led back towards the sprue. However, there is no direct connection between the sprue and the branch back. Rather, only melt from the directed branch of the casting run in the

backward branch. The temperature of the melt flowing through the runner as it is poured into the mold decreases with increasing distance from the gate. Accordingly, in a casting mold according to the invention, hot melt flows into the feeder system via the gate adjacent to the sprue closest to the sprue, whereas the melt, which runs into the feeder system via the furthest away from the sprue in the direction of flow of the last branch, has cooled to a maximum , There is therefore a maximum difference in temperature between the melt entering the feeder system via the first gate of the branched branch and the last gate of the returned gate. By supplying the maximum hot and the maximum cooled melt to the same region of the casting mold, the melt streams of different temperatures mix and a melt temperature arises in the melt contained in this region, which, for example, the melt volume flows entering the region in question mean temperature of the inflowing in this area, maximum hot and maximum cooled melt streams corresponds.

Between the melt, which is passing through the provided in the direction of flow at the end of the branched away last branch of the weggestickte branch into the feeder system and cooled along the way along the feeder system, and the melt that passes through the first gate of the back branch in the feeder system and is cooled only a little over a comparatively short distance between the last gate of the path branch and the first gate of the back branch, there is only a correspondingly small temperature difference. Since these comparatively slightly differently tempered melt streams are supplied to the same area of the feeder system, there is also a mixing temperature there. This can in turn by a suitable adjustment of the cuts in the Feeding system entering melt volume flows are adjusted so that the mixing temperature in the area in question is equal to the mixing temperature, which is adjusted by mixing the maximum hot and the maximum cooled melt in the adjacent to the sprue area of the feeder system.

In the same way, it is with the melt streams that are routed through those optionally existing further gates in the feeder system, along the directional and the backward branch of the casting between the - seen in the flow direction of the melt - at the end and at the beginning of the directed and of

backward branches provided there are provided.

As a result, a homogeneous over the entire volume of the feeder system temperature distribution is thus achieved by the provided in a mold according to the invention design of the casting run and its special connection to the feeder system. Along with this, the melt passing into the casting mold cavity via the feeder system also has a uniform temperature distribution, as a result of which, even in the case of a filigree shaping, the melt to be imaged on the casting

Design elements, such as thin walls and fine webs or ribs, not only achieves optimum mold filling, but one as well

uniform solidification of the melt is achieved. Consequently, the invention also makes it possible to develop components which are difficult to control, such as cylinder crankcases, for cast metal, which are known for their poor mold filling and feeding capacity, but which can develop high mechanical or thermal properties

Internal combustion engines, to pour.

As mentioned, the mixing temperature in the feeder system can be adjusted by tuning the melt volume flows entering the individual regions of the feeder system via the gates provided there be set. For this purpose, the position on the respective branch of the run, the number or geometry, in particular the

Diameter, the cuts are adjusted so that from the proportions of the entering into the feeder system, different

tempered melt streams at the total melt volume contained in the feeder system the desired mixing temperature in the

Feeder system yields.

By the arrangement of the the directed and the

In this case, the mixing back of the branch, which in each case is assigned to the branch in the feeder system and, consequently, the equalization of the temperature of the melt contained in the feeder system, can be directly influenced.

In this case, the inventive design of a casting mold proves to be advantageous in all casting tasks in which a particularly homogeneous temperature distribution in the respectively to be cast melt and a uniform supply of the melt in the casting mold cavity representing the casting for the casting success are important. Thus, the invention for castings with an elongated, block-like basic shape, such as engine blocks, can be used as well as for

Castings that have a cylindrical, embossed by an ellipsoidal or circular cross-section basic shape.

With regard to an optimized homogeneity of the temperature distribution, it has proved to be advantageous if, for each gate over which the path-oriented branch of the casting is connected to the feeder system, one of the gates is arranged opposite, via which the returned branch is connected to the feeder system , This is advantageous, in particular, in the case of a feeder system whose length is appreciably greater than its width, that is to say for example a feeder system which has a rectangular basic shape in plan view. Likewise for equalizing the temperature distribution of the melt contained in the casting system in the casting system, it contributes, if the number of gates associated with the path away is equal to the number of gates associated with the returned branch.

The latter applies in particular if the size of the part of the path directed towards the branch is the same as the size of the part of the branching back, if the sections are dimensioned in such a way that the branches of the branches of the branch are interspersed

Gießlaufs each equal volume flows get into the feeder system.

Depending on the manner of connection of the feeder system to the mold cavity or the dewatering of the mold cavity during the solidification of the melt in the feeder system required

Melt volume, it may be appropriate to provide in the feeder system, a single sufficiently large feeder chamber, in

According to the invention way is connected via gates with the weggerichtet and the backward branch of the casting run. The feeder chamber then serves as a mixing area for the over the away and the

backward branch into them reaching melt and thus contributes to

Homogenization of entering the mold cavity melt at. In addition, such a feeder chamber can take over a feeding function in the sense of a make-up of melt in the mold cavity of the mold.

If the mixing and the concomitant equalization of the temperature distribution of the melt contained in the feeder system to be further optimized, it may be appropriate to provide two or more feeder chambers in the feeder system, each of which at least one gate both with the wegfällig branch and with backward branch of the run is connected. At two or more Food chambers contain the individual chambers only one

Partial volume of the total melt volume required for the make-up of the mold cavity. By the correspondingly lower

The volume of the individual feeder chambers results in a particularly intensive mixing of the differently tempered melt streams entering the branches of the casting run. In this way, it can be ensured with comparatively little effort that the melt volumes present in the respective melting chamber as a whole have the desired mixing temperature, and the formation of local temperature differences is avoided. In this regard, it proves to be particularly favorable when the of the

Speiser chambers comprised volumes are the same.

For a feeder system with two or more feeder chambers to ensure that contained in the individual chambers

Speiservolumina assume a common mixing temperature, the feeder chambers can be provided with each other in addition, the

Be connected to feeder chambers directly connecting gates. About these additional cuts it comes to the exchange of in the

Speiser chambers contained melt volumes and, consequently, to compensate for the possibly different temperatures of the melt portions contained in the chambers.

A particular for casting cylinder crankcases for

Internal combustion engines with cylinder openings arranged in a row suitable variant of the invention is characterized in that the feeder system at least one, in particular at least two

comprises juxtaposed feeder chambers, and either the weggerichtete branch in the space between the feeder chambers is arranged and along with respect to the gap

outside of each of the feeder chambers in each case a branches off the branched branch branches back branch or runs The branched branch is divided into two branched branches, one each along the gap between them

Feeder chambers outboard side of the feeder chambers runs, whereas at least one associated with the weggerichteten branches back-aligned branch runs in the space between the feeder chambers. The uniform division of the melt onto the feeder chambers can be supported by the fact that the runner in the

branched direct connection to the sprue in two leading branches, to each of which a returning branch is connected.

It proves to be particularly advantageous with regard to the distribution of the melt onto the branches of the casting run of a casting mold according to the invention if the branches of the casting run are arranged together in one plane. This level is optimally oriented horizontally in the casting operation, so that a gradient and, consequently, different

Flow velocities in the branches of the run are avoided.

In the case of such a common plane for the branches of the run, it has proved to be advantageous if the gates of the supply and

each returning branch have their own level, so that the melt is layered during convergence and does not collide.

Another embodiment of the invention, which is particularly important for practice, is that of the feeder system or of the run to

Mold cavity leading connection is performed only outside of the cavity occupied by the mold cavity volume of the mold. In the case of a casting mold according to the invention, the melt is introduced into the mold exclusively via connections which are formed on the outside in the region of the walls of the casting mold cavity which delimit the casting mold cavity

Mold cavity is passed, the uniformity of the Temperature distribution of the inflowing into the mold cavity in the casting operation melt and the uniformity of the mold filling optimized.

By taking place exclusively outside of the mold cavity connection temperature differences in the melt introduced into the mold cavity are avoided in the casting operation. These may occur when melt is also passed into the mold cavity via heated inner cores heated by the melt flowing into the mold cavity, which images recesses, cavities, channels and the like in the casting. Due to the heating of the internal cores, the melt flowing through them would cool less than the melt supplied via the external connections. Since the melt is supplied to the mold cavity only via external connections, it is thus ensured that the melt on its way from

Feeder system or evenly cooled by the casting into the mold cavity and thus enters the mold cavity at a uniform temperature.

As in this regard, it has proven to be particularly advantageous if, in the case that the feeder system via several connections to the

Mold cavity is connected, the feed system associated with the inlet openings of the connections are arranged together in a plane. In this way, the melt is discharged from the feeder system at the same level at which a uniform temperature of the melt contained in the possibly several chambers is removed. This also contributes to the fact that the reaching into the mold cavity

Melt has a uniform temperature in the technical sense.

The casting mold according to the invention is suitable for gravity casting or low pressure casting. In particular, can be with

casting molds according to the invention in Kippguss- or

Produce rotational molding processes in which the casting mold to or is moved during filling from a filling position in a solidification position. A summary explanation of these methods can be found in EP 2 352 608 B1 and the prior art cited therein.

In order to be able to image the filigree design features of casting parts to be cast by casting molds according to the invention, the casting mold according to the invention can be composed of a plurality of cores, of which certain cores map the outer shape and other cores in the casting to be produced

Recesses, cavities, channels and the like. In this case, the cores of the core package as a whole can be designed as lost cores, which are destroyed in the demolding of the casting, or some of the cores are formed as permanent moldings that can be used repeatedly.

Thus, in particular in the case which is particularly advantageous in practice, the connection of the feeder system to the mold cavity

is realized exclusively via connections that are outside of

Mold cavity lie, for example, be useful, in a mold according to the invention designed as a permanent mold part

Provide outer shell, on which at least the connections are at least partially bounded casting cores are held. This proves to be particularly advantageous if the connections, at least partially delimiting casting cores as lost

Casting cores are formed.

The invention thus achieves the representation of a cylinder crankcase in the core package process with a feed system in which the melt is divided into two casting branches, so that the connected thereto, optimally pot-like feeder chambers comprehensive feed system for homogenization of the temperature distribution in the feeder system and subsequently in the molded by the mold component serves. in the Casting operation, the feeder system is filled by its two- or multiple gates to the branches of the casting run by melt different temperature. By adapting the geometries and the position of the gates, a mixture of the melt in the feeder system is achieved in such a way that in the feeder system as a whole a homogeneous

Temperature distribution results. The correspondingly homogeneously tempered

Melt is fed to the casting cavity forming the casting.

The pouring course made possible by the design according to the invention makes it possible, in particular in combination with the feeding of the mold cavity, and optionally with it, that is optionally exclusively from the outside

accompanying avoidance of "internal" supply paths, poorly castable light metal melts, such as alloys based on Al-Cu, despite their generally poor filling and feeding capacity free of macroscopic

Shed defects. The feeders and external connections present on the casting after demolding of the casting can be easily weight-neutralized by common machining methods, such as e.g. Drilling, to be removed. Mass accumulations on the casting, which are provided in the prior art to prevent local premature solidification of the melt, but do not fulfill any other technical purpose can be avoided in a mold according to the invention as well as to avoid freezing phenomena consuming channel guides in the connection of the feeder system to the

Mold cavity.

Of course, cooling molds can also be arranged in a casting mold according to the invention in the region of the mold cavity in order there to effect locally accelerated solidification in a manner known per se

Training a locally particularly pronounced structure too

accomplish. In particular, when the filling and make-up of the mold cavity with melt takes place exclusively via external connections, these cooling molds in the casting operation also do not hinder the guaranteed by the inventive design uniform filling.

The invention will be explained in more detail with reference to an exemplary embodiments illustrative drawing. Their figures show each schematically and not to scale:

1 shows a casting mold for casting a cylinder crankcase for an internal combustion engine in a cross section;

Figure 2 is a cast in the mold 1 cylinder crankcase after demolding in the un-cleaned state in a view from above.

3 shows the cylinder crankcase according to FIG. 2 in a frontal view of its one end face;

Fig. 4, the cylinder crankcase according to FIGS. 2 and 3 in one

lateral view.

Fig. 5 shows another mold for casting a

Cylinder crankcase for an internal combustion engine in a cross section;

Fig. 6 - 9, the mold according to Figure 5 when filled with melt;

Fig. 10, the mold according to FIG. 5 in the after filling for

Freezing turned position.

The mold 1 shown in Fig. 1 is used for casting of the cylinder crankcase Z shown in Figures 2-4, often called cylinder blocks, for an internal combustion engine made of an AICu alloy. Fig. 1 shows schematically a section transverse to the longitudinal extent of the cylinder crankcase Z.

Trained as a core package mold 1 comprises two trained as permanent moldings outer shells 2.3, between which a larger number of than molded in the usual way from molding sand lost Gießkemen 4 are arranged. The outer shells 2, 3 and the casting cores 4 surround a mold cavity 5, which images the cylinder crankcase Z to be cast with its four cylinder openings ZÖ arranged in series and the design features usually provided for such internal combustion engine cylinder crankcases.

Furthermore, the casting cores 4 delimit a sprue, not visible in FIG. 1, perpendicular from the side 6 of the casting mold 1 arranged at the top in FIG. 1, a casting run 7 connected to the sprue, a casting run 7 and the casting cavity 5 connected feeder system 8 and for connecting the mold cavity 5 to the runner 7 or the feeder system 8 provided connections 9a, 9b.

The mold 1 is shown in Fig. 1 in the position shown for filling with melt, wherein the opening of the sprue faces up and the feeder system 8 is arranged on the underside of the mold 1.

After filling the melt, the mold 1 is closed in a conventional manner and in a known manner about a parallel to the longitudinal extent of the mold 1 aligned pivot axis rotated by 180 °, for example, until the feeder system 8 is arranged above. In this way, a running in the direction of the feeder system 8 uniform solidification of the filled mold 1 in the melt

favored. When solidifying, not only the one to be formed forms

Cylinder crankcase Z as a solid cast body from, but there are after demoulding as a result of in the sprue 10, in the run 7, in the feeder system 8 and in the connections 9a, 9b solidifying melt these originally hollow form of the mold elements 1 with the

Cylinder crankcase Z shown contiguous.

When cleaning following demoulding, the relevant

Form elements of the cylinder crankcase Z separated in a conventional manner and supplied for recycling.

The peculiarities of a casting mold 1 according to the invention can thus be most easily removed from the demoulded and not yet cleaned

Cylinder crankcase Z explain, as shown in Figures 2-4.

The feeder system 8 therefore comprises two juxtaposed rows extending in the longitudinal direction L of the cylinder crankcase Z, each having five pot-type feeder chambers 11, 12. Adjacent to each other feeder chambers 11, 12 of each row are connected by gates 13,14. The rows of

Feeder chambers 11, 12 define a gap 15 between them.

The feeder chambers 11, 12 are above the provided for a mounting of a cylinder head not shown here top surface ZD of

Cylinder crankcase Z arranged and have identical shapes and volumes. The bottoms of the feeder chambers 11, 12 are arranged together in a horizontal plane H1, which is aligned parallel to the top surface ZD of the cylinder crankcase Z.

The runner 7 is also in a parallel to the top surface ZD

arranged horizontal plane H2, in which also the upper side of the feeder chambers 11, 12 ends. The runner 7 is divided starting from the head 17 of the demolded cylinder crankcase Z as slightly conically tapered in the direction of the runner 7 tapered sprue 10 into two branches 18,19, seen in the flow direction S in the casting operation in the mold 1 melt seen from Einguss 10 are directed away.

With respect to the longitudinal axis L of the cylinder crankcase Z in

Seen top view (Fig. 2) mirror-symmetrically shaped, away from the sprue 10 branches 18,19 go to this first each transverse to

Longitudinal axis L from the pouring head 17 from then to pass in a curve and via a respective filter F in a section which extends at a small distance along the side facing away from the gap 15, the outer side of the respective series of feeder chambers 11, 12 extends.

At the end of the respective row of feeder chambers 11, 12, as viewed in the flow direction S, the branched branches 18, 19 in a further curve pass into a section aligned against the respective other branch 19, 18 which extends across the width of the respective row of feeder chambers 11, 12 extends.

At the end of this section, as seen in the direction of flow S, the branched branches 18, 19 of the run 7 open together in a branch 20 of the run directed back in the direction of the pouring head 17. This back-directed branch 20 of the run 7 has a cross-sectional area which corresponds at least approximately to the sum of the cross-sectional areas of the directed branches 18, 19. In this way, the back-directed branch 20 can safely receive the melt volumes flowing into it via the knurled branches 18, 19.

The back-directed branch 20 is arranged in the intermediate space 15 centrally between the rows of feeder chambers 11, 12 and extends in

Flow direction S considered opposite to that of the sprue 10th directed branches 18,19 on the gate 10 to. However, the back-directed branch 20 terminates in front of the pouring head 17, so that in the casting operation, melt passes into the back-directed branch 20 exclusively via the knurled branches 18, 19.

Each of the evenly spaced along the longitudinal axis L

arranged feeder chambers 11 is via a respective gate 21 with the weggestichteten branch 18 and each also in uniform

Distances arranged in the longitudinal direction L feeder chambers 12 is connected via a respective gate 22 with the weggestichteten branch 19.

Similarly, each of the feeder chambers 11 is connected via a respective gate 23 and each of the feeder chambers 12 via a respective gate 24 with the back-branch 20. The gates 21 - 24 are also distributed at equal intervals along the longitudinal axis L, wherein the each feeder chamber 11, 12 respectively associated gates 21, 22; 23,24 opposite to each other and centrally relative to the respective wall of the feeder chambers 11, 12 are positioned.

The mold cavity 5 is connected via links 9a, 9b directly to the

Casting 7 (connection 9a) or the feeder chambers 11, 12 (connections 9b) connected. The connections 9a, 9b are exclusively formed outside the mold cavity 5, so that no melt passes into the mold cavity 5 via casting cores 4 placed in the mold cavity 5. According to the principle of communicating tubes, the

Melting a level, logically reaches a portion of the melt via the feeder chambers 11, 12 in the mold cavity 5. The solidification in the component passes over the thin walls then very quickly and the supply is made only on the locally large volume in close proximity to

Power requirements. The mouth of the connected to the feeder chambers 11, 12 connections 9b are on a common

Horizontal plane H3 arranged so that each equal tempered

Melt from the feeder chambers 11, 12 in the connected to it Connections 9b arrives. The supply of the melt to the mold cavity 5, however, can extend over a height range or distribute over several levels.

With regard to the filling or the solidification behavior of particularly critical regions of the mold cavity 5, it is possible to selectively supply melt through a dedicated connection 9b in order to feed the respective problem location directly.

The mold 31 shown in FIG. 5, which is constructed entirely of core cores from lost cores, is also provided for casting a cylinder block for an internal combustion engine. The casting mold 31 comprises a cover core 32, an outer core 33 carrying the cover core 32, a further outer core 34 carrying the outer core 33, two outer shell cores 35, 36 forming the outer end of the casting mold 31 in the region of the mold cavity of the casting mold 31 on which the outer cores 33,34 and the lid core 32 are supported, one the contour of the interior of the

Casting imaging contour-forming core 37, which forms the lower end of the mold and on which the pot cores 35,36 are supported, and within the laterally bounded by the shell cores 35,36 space cores 38,39, which determine the outer contour of the casting.

In the lid core 32 are directed away from here not visible sprue, outwardly extending branches 40,41 and a centrally arranged

molded back branch 42 of the casting run. In the intermediate space between the respectively arranged on the outside, directed away branch 40,41 and the back branch 42 is in each case a feeder pot 43,44 in the lid core 32 and the outer cores 33,34 formed. The feeder pots 43,44 accordingly sit directly on the top surface of the casting (e.g.

Sealing surface to the oil sump or to the cylinder head). The feed pans 43,44 feed thus all areas, which are arranged in direct local proximity to them are, such as the cylinder head screw pipes. The

Branched branches 40,41 are via junctions that are close to

Outer core 33 are arranged, connected to the respectively associated riser 43,44, whereas the back-branch 42 is connected via connections with the feeder pots 43,44, which are offset in the direction of the top of the lid core 32.

The shell cores 35, 36 and the respective cores 38, 39 that determine the outer contour of the casting also additionally delimit external feed volumes 45, 46, which are connected to one of the feeder pots 43, 44 via a respective feed 47, 48. The external feed volumes 45, 46 are filled via the associated inlet 47, 48, which is always connected to one of the feed pots 43, 44. The external feed volumes 45, 46 thereby feed everything in their immediate vicinity, e.g. Mass accumulations through functional integration.

While the feeder pots 43,44 are at the time of pouring

Cylinder crankcases ZK particular mold 31 are always on the same level, are the external feed volumes 45,46 at different heights.

For filling with melt, the mold 31 is rotated for example by a transverse to the longitudinal extent of the cylinder crankcase ZK to be cast by 80 °, so that the lid core 32 is located with the directional branches 40,41 and the back branch 42 at the bottom. Hot melt M is directed into the straightened branches 40,41 via the gate. From the bent branches 40, 41, the melt M cooled on the way through the turned branches 40, 41 passes into the branch 42 and back into the feed pots 43, 44 (FIG. 6).

With increasing filling of the weggestichteten branches 40,41 also hot melt M passes through the corresponding compounds of the directed branches 40,41 in the feeder bowls 43,44, so that in the feeder bowls 43,44 hot melt M and cooled melt M mixes and in the feeder bowls 43,44 melt M is present, which has a homogeneously distributed mixing temperature (Fig. 7).

The appropriately tempered melt M rises via the inlets 47, 48 on the one hand into the external feed volumes 45, 46 and on the other hand via the gates, via which the feeder heads 43, 44 are connected directly to the casting mold cavity forming the casting, into the casting mold cavity (FIG ).

After complete filling (FIG. 9), the casting mold 31 is closed in a manner known per se and turned through 180 ° into the solidification position transversely to its longitudinal extent (FIG. 10).

In the embodiments described here a

The mold according to the invention thus the melt is filled via at least one gate into the mold. The melt is then divided into two separate, directed away from the sprue branches, which are preferably aligned with a corresponding basic shape of the feeder system so that they are at least partially parallel. The melt, which is split up on the branches of the run, is returned to the pot-like feeder chambers via a diversion. In this case, in the region of the deflection, a curve can be provided which leads out of the main plane, in which the casting is mainly, in order to decelerate the flow velocity of the melt flowing through the respective branch oriented branch. The concerned to the concerned

Curve train subsequent section of each branch is then back in the main level of the watering. Following the straightened branches, the melt is returned to at least one central one

Casting continued. Of course, it is also possible to return to each branched branch of the run a private, also to connect in the space between the rows of feeder chambers extending branch.

The early separation of the runner system and delivery of the melt to multiple feeder volumes provided by the feeder chambers results in optimized fill conditions. Thus, by the inventive

Design a rapid, uniform inflow of molten metal and thus a homogeneous temperature distribution in the feeder system and in the component guaranteed. For this purpose, the runners are connected via gates with the feeder chambers. The connection of the feeder chambers is chosen so that it is optimal in the chambers

Mixing of the penetrating melt comes. For this purpose, it may also be useful, for example, not to tie all the feeder chambers directly to the runner, as in the exemplary embodiment explained here, but to separate feeder chambers only with the immediately adjacent one

Connecting feeder chamber, which is then connected to the runner. To support the mixing and the temperature compensation, the feeder chambers are connected to each other via gates. By varying the gate cross-sections and the feeder chamber volumes, the melt flow and the achieved temperature distribution can be adapted to the respective casting task. The fact that the feeder system is arranged during the solidification above the mold cavity, a solidification is achieved in the direction of the feeder system. That is, the component cools and solidifies starting from the location furthest away from the feeder system, while the melt contained in the feeder system and finally filled into the mold remains hot for a longer time. If the mold is gravity-cast without rotation, i. filled with overhead feeder system, so first the mold cavity forming the casting and finally the feeder system is filled.

The easy removal of the feeder system, the runner, the sprue and the connections can be supported by the fact that the Connections are small area connected to the component contour. The connection points preferably go on existing slugs and sit on surface, which are part of the standard post-processing. The feeder system can be easily removed, for example, by drilling during the pre- and post-processing of the respectively obtained component (cylinder crankcase Z).

REFERENCE NUMBERS

mold

2.3 outer shells

4 casting cores

5 mold cavity

6 side of the mold 1

7 watering

8 feeder system

9a, 9b connections

10 sprue

11, 12 food chambers

13,14 gates

15 of Speiserkammern 11, 12 limited space

17 pouring head

18,19 directed branches of the run 7

20 backward branch of the run 7

21-24 cuts

L longitudinal axis

F filter

H1-H3 Horizontal planes, parallel to the top surface ZD of the

Cylinder crankcase Z aligned

S flow direction of the melt

Z Cylinder crankcase

ZD top surface of the cylinder crankcase Z

ZÖ cylinder openings

31 casting mold

32 lid core

33.34 outer cores

35.36 outer shell cores

37 the inner contour of the casting ZK determining core

38.39 cores that determine the outer contour of the casting.

40.41 directed, outside branches of the run

42 centrally arranged backward branch of the run

43,44 feeder pots

45.46 external feed volumes

47.48 feeds

ZK Cylinder Crankcase (Casting)

M melt

Claims

PATE CLAIMS

A mold for casting complex-shaped large-volume castings (Z) from a molten metal, wherein the mold (1) comprises a mold cavity (5) forming the casting (Z) and a feeding system for supplying the molten metal to be cast to the casting (Z) in the mold cavity (5), wherein the feed system comprises a gate (10), one to the

Casting connected (7) and a feeder system (8), which is connected to the casting run (7), and wherein the

Mold cavity (5) with the feeder system (8) or the run (7) via connections (9a, 9b) is connected, characterized

characterized in that the casting run (7) - viewed in the direction of flow (S) of the molten metal flowing from the gate (10) into the casting run (7) during casting - with a branch (18, 19) directed away from the gate (10) along the feeder system ( 8) and with a backward branch (20) adjoining the branched branch (18, 19), in the opposite direction to the branched branch (18, 19) along the branch

Feeder system (8) is guided, and that the feeder system (8) arranged both with the weggearbeitet branch (18,19) and with the back branch (20) over two or more along the respective branch (18,19,20) arranged distributed Gates (21-24) is connected.

2. Casting mold according to claim 1, characterized in that the number of the weggerichteten branch (18,19) associated with gates (21, 23) is equal to the number of the recessed branch (20) associated with gates (22,24).

3. Casting mold according to one of the preceding claims, characterized

in that for each gate (21, 23) over which the branch (18, 19) of the run (7) connected to the feeder system (8) is connected, one of the gates (22, 24) is arranged opposite to the return branch (20) is connected to the feeder system (8).

4. Casting mold according to one of the preceding claims, characterized

characterized in that the size of the part (21, 23) associated with the branching branch (18, 19) is equal to the size of the notches (22, 24) associated with the back branch (20).

5. Casting mold according to one of the preceding claims, characterized

characterized in that the feeder system (8) comprises at least one, two or more feeder chambers (11, 12), each of which has at least one gate (21-24) with both

directed away branch (18,19) and with the back-branch (20) of the casting run (7) is connected.

6. Casting mold according to claim 5, characterized in that the feeder chambers (11,12) are interconnected via a gate (13,14).

7. Casting mold according to one of claims 5 or 6, characterized

in in that the feeder system (8) comprises at least two juxtaposed feeder chambers (11, 12), and

-that

- either the weggerichtete branch (18,19) in the intermediate space (15) between the feeder chambers (11,12) is arranged and along the relative to the intermediate space (15) outer side of each of the

Feeder chambers (11,12) extending from the directed branch (18,19) branching back branch (20)

- Or the casting (7) is divided into two weggestichtete branches (18,19), one of which extends along the relative to the intermediate space (15) between the feeder chambers (11,12) outer side of the feeder chambers (1,12) whereas at least one branched branch (20) connected to the upright branches (18, 19) runs in the intermediate space (15) between the feeder chambers (11, 12).

8. A mold according to claim 7, characterized in that the casting run (7) in the immediate connection to the sprue (10) is branched into two branched branches (18,19), to the at least one

back-directed branch (20) is connected.

9. Casting mold according to one of the preceding claims, characterized

in that the branches (18, 19, 20) of the casting run (7) are arranged in one plane (H2).

10. Casting mold according to one of the preceding claims, characterized

characterized in that it is composed as a core package of a plurality of cores (2, 3, 4), of which certain cores (2, 3, 4) are the outer mold and other cores (4) in the casting to be produced depicting recesses, cavities, channels and the like.

11. Casting mold according to one of the preceding claims, characterized

in that the connection (9a, 9b) leading from the feeder system (8) or from the run (7) to the mold cavity (5) is guided exclusively outside the volume of the casting mold (1) occupied by the mold cavity (5).

12. Casting mold according to claim 11, characterized in that in the case of a plurality of connections (9a, 9b) the feed system (8)

associated inflow openings of the connections (9a, 9b) are arranged together in a plane (H3).

13. Casting mold according to one of claims 10 to 12, characterized

in that at least the cores (4) delimiting the connections (9a, 9b) at least in sections are arranged in one

Outer shell (2,3) of the mold (1) are held.

14. A mold according to claim 13, characterized in that the outer shell (2,3) is formed as a permanent mold part, which is retained after removal of the casting (Z), whereas the casting cores (4) as lost, destroyed during demolding casting moldings a molding material on Gießsandbasis exist.

15. Use of a according to any one of the preceding claims

formed mold (1) for casting a cylinder crankcase (Z) for a combustion engine from a light metal melt.