DE102008015856A1 - Method for casting components e.g. cylinder crankcases made of light alloys according to the tilt pouring concept, comprises filling melt into assembly assigned to mold and then flowing into mold cavity during tilting motion of the mold - Google Patents

Abstract

The method comprises filling melt into an assembly assigned to a mold (1) and then directly flowing into a mold cavity during a tilting motion of the mold, and swiveling the mold with an assigned casting machine into an initial position (A) of 90[deg] . The melt is filled in a separate and independent casting ladle or in a casting basin arranged at the mold. The tilting procedure (K) of the mold is carried out with a variable tipping speed, where the filling process is locked with a tilting angle of the mold of 0[deg] (B). An independent claim is included for device for casting components made of light alloys according to the tilt pouring concept.

Description

The The invention relates to a method and a device for casting of components made of light metal according to the Kippgießprinzip, wherein the melt in an associated with the mold assembly is filled and out of this assembly during a tilting movement of the mold flows into the mold cavity.

After this for internal combustion engines for decades predominantly cast cylinder crankcases used in cast iron are made of technical and environmental aspects the cylinder crankcase for small-volume internal combustion engines increasingly made of light metals. For this were due to their low specific weight, first magnesium alloys used, which are however cost-intensive and one only have low strength and corrosion resistance. Substantially less expensive are aluminum-silicon alloys, in addition, a better corrosion resistance exhibit. This has meant that modern and in large Quantities manufactured internal combustion engines often with Cylinder crankcases made of aluminum-silicon alloys be fitted while cylinder crankcase made of magnesium alloys almost exclusively for used in racing.

The Cylinder crankcases come with different casting processes of which die casting, low pressure casting, Sand casting and lost foam casting are to be mentioned. Each of the procedures results in an application for cylinder crankcase some advantages, but also process-specific disadvantages.

So can in a production by die casting no Undercuts are realized. That's why you can For example, with die casting the water area is not in one so-called "closed deck" variant, with higher mechanical strengths in some areas and reached larger water flows could become.

At the Low pressure casting results in restrictions because the Casting mold until complete solidification with the casting furnace must remain connected. This will increase the profitability of Production impaired.

At the Sand casting and Lost-Foam casting have lower mechanical strengths reached. This is due to the lower compared to steel tools Thermal conductivity of a sand mold.

The still cause increasing performance of internal combustion engines basically a higher load of aluminum manufactured cylinder crankcase, especially in the area at the main camp. For this, the designer must Casting methods are available with which the specific performance of aluminum as a material can be exploited. This has to be various modifications the already known methods performed with which primary Advantages for casting light metal components to be sought.

So describes DE 10 2004 015 649 B3 a method and a device for casting of components made of light metal, preferably of aluminum alloys, with the gravity chill casting, especially in the Kippgießverfahren. In this case, arranged on the longitudinal side of a mold with upwardly facing sprue connected thereto cross, which is designed so that at 45 ° to 70 ° about its longitudinal axis tilted mold initially about 20% of the required melt for the melt volume in the cross can flow without this melt already flows into the actual mold cavity. Thereafter, the mold is tilted back with further filling of melt volume in the transverse movement in its vertical position, the melt now flows through outlets from the cross-section into the mold cavity. Thus, a casting method with controlled mold filling is realized, with the better properties are achieved than with a casting process with very fast mold filling. As a result, cavities, porosities and inclusions in the casting are largely avoided even in complicated components, such as cylinder crankcases. However, a disadvantage is the arrangement of the sprue at the front end of the cross run, whereby the melt has to travel relatively long distances. Furthermore, the "intermediate storage" of a subset of the melt volume in cross-flow is problematic. As a result of sprue arrangement and intermediate storage, the process time is increased and undesirable cooling may occur.

task The invention is a technical solution for casting of geometrically demanding components made of light metal in the tilt casting process to create, the short cycle times and a good microstructure education during the solidification of the melt allows.

These Task is solved by the mold with a assigned casting machine in a starting position of up is pivoted to 90 °, the mold being in a range of 0 ° to 90 ° is displaced. Advantageous embodiments are the subject of dependent Claims, their technical features and effects in Embodiment described in more detail.

The technical solution according to the invention is suitable for pouring various components made of light metal in Kippgießverfahren. A preferred application is the production of geometrically demanding components made of aluminum alloys, in particular cylinder crankcases for internal combustion engines. Regardless of the concrete casting in each case, short cycle times and good microstructure during the solidification of the melt are guaranteed.

By the production of the cylinder crankcase in gravity chill casting with the Kippgießverfahren is a laminar mold filling reached. This allows air and oxide inclusions, for example, by melting splash, largely avoid and the strength of the structure is increased. The procedure Can be used on rotary table and linear systems, whereby a high economy is achievable.

At the Kippgießverfahren invention the casting tool in a starting position of up to 90 ° means pivoted a corresponding casting machine. That for the pouring of the respective component necessary melt volume is filled in a separate ladle by an associated device tilted independently of the casting machine can be. Alternatively to the use of a ladle can the necessary melt volume in a casting tool arranged casting basins are filled.

To At the start of the tipping process, the mold filling begins for the respective concrete component. Due to the tilt angle, the maximum Filling height for the cast component reduced. Thus reduces during the mold filling the kinetic energy of the melt and a controlled laminar mold filling is reached. The tipping process runs with one each specific adapted variable tilting speed. At a tilt angle from 0 °, the filling process is completed and the solidification position for the cast component, for example a cylinder crankcase is reached.

The separate pouring ladle or the pouring basin is preferably centrally on the longitudinal or front side of the Cylinder crankcase positioned. This will cause the melt led directly into the component geometry without this an unnecessary cooling occurs.

With a large proportion of steel molds are compared for sand and lost foam casting an accelerated solidification by faster heat transfer and thus higher mechanical Strength values achieved. By cooling circuits in the moldings, the solidification can be additional accelerated and the solidification direction are influenced.

By the controlled mold filling with lower melt speeds Sand cores can be inserted into the mold and thus undercuts realize. Consequently, greater freedom of design results for the construction of the casting concerning the arrangement of cast channels. Furthermore you can The processing costs are reduced as well as a larger one Stiffness, optimized oil flow and partially also a weight reduction of the casting can be achieved.

One Embodiment of the invention is in the drawing and will be described below. It show in each case schematic representation:

1 a first embodiment of a Kippgießmaschine for application of the technical solution according to the invention

2 a second embodiment of a Kippgießmaschine for applying the technical solution according to the invention

3 a Kippgießmaschine with casting and casting system in the starting position for the mold filling

4 the relative position between watering ladle or pouring basin and the casting to be produced

In The drawing is the basic structure of a Kippgießmaschine shown. The functional active compound of the corresponding Assemblies is known per se, so at this point on closer statements in this regard can be dispensed with. following become merely the essential features of the present invention explained in more detail.

1 and 2 show different versions of Kippgießmaschinen each with a mold 1 for casting a cylinder crankcase 2 made of light metal. The mold 1 is supported on the Kippgießmaschine such that it is displaceable in a range of 0 ° to 90 °. For this is the mold 1 tiltable about a longitudinal axis, wherein the pivot point by the reference numeral 3 is designated. Furthermore, the casting mold 1 associated with a top-fillable assembly for the volume of melt, as a ladle 4 or as a pouring pool 4 is designed. Out 3 is a starting position with representation of ladle 4 or pouring basin 4 seen.

If a ladle 4 is used, this is preferably designed as a separate assembly which is tiltable regardless of the casting machine. By contrast, an alternatively provided pouring basin 4 preferably firmly on the mold 1 arranged. Regardless of their particular design, the ladle 4 or the pouring basin 4 preferably arranged centrally on the longitudinal or front side of the respective component. A related relative position, for example, compared to a cylinder crankcase 2 , is out 4 seen.

The mold 1 can be configured differently. So can in the mold 1 For example, additional cooling circuits are configured, with a relevant variant is not shown in detail in the drawing.

During the casting process, the casting mold can 1 be tilted by the Kippgießmaschine first in a starting position of up to 90 °. The starting position is in 1 and 2 denoted by the reference "A". During a tilting movement, which is stylized with an arrow "K", the melt flows out of the ladle 4 or the pouring basin 4 directly into the mold cavity of the mold 1 one. The tilting process "K" of the mold 1 is preferably performed with a variable tilting speed, wherein the filling process at a tilt angle of the mold 1 of 0 ° is completed. This end position of the mold filling is in 1 and 2 denoted by the reference "B".

1

mold

2

cylinder crankcase

3

pivot point

4

Ladle / casting pool

A

starting position mold filling

B

end position mold filling

K

tilt

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - DE 102004015649 B3 [0008]

Claims (10)

A method for casting light metal parts according to the tilt casting principle, wherein the melt is filled into an assembly associated with the mold and flows from this assembly during a tilting movement of the mold into the mold cavity, characterized in that the casting mold ( 1 ) is pivoted with an associated casting machine in a starting position (A) of up to 90 °. A method according to claim 1, characterized in that the melt volume in a separate and independently of the casting machine tiltable ladle ( 4 ) is filled and flows from there directly into the mold cavity. A method according to claim 1, characterized in that the melt volume in one of the casting mold ( 1 ) arranged Gießtümpel ( 4 ) is filled and flows from there directly into the mold cavity. A method according to claim 1, characterized in that the tilting process (K) of the casting mold ( 1 ) is performed with a variable tilting speed, wherein the filling operation is completed at a tilt angle of the mold of 0 ° (B). Apparatus for casting light metal components according to the tilt casting principle, the apparatus having a casting mold which can be tilted about its longitudinal axis and having a melt volume which can be filled from above, from which the melt flows into the mold cavity during a tilting movement of the casting mold, characterized in that Casting mold ( 1 ) is displaceable in a range of 0 ° to 90 °. Apparatus according to claim 5, characterized in that the device is a separate pouring ladle ( 4 ) which is tiltable independently of the casting machine. Apparatus according to claim 6, characterized in that the separate pouring ladle ( 4 ) centrally on the longitudinal or front side of the respective component ( 2 ) is arranged. Device according to claim 5, characterized in that the device is attached to the casting mold ( 1 ) arranged Gießtümpel ( 4 ) having. Apparatus according to claim 8, characterized in that the pouring basin ( 4 ) centrally on the longitudinal or front side of the respective component ( 2 ) is arranged. Device according to claim 5, characterized in that in the casting mold ( 1 ) are designed additional cooling circuits.