Casting Die and Method for Producing Cast Workpieces Consisting of Light Metal Alloys

Abstract

The invention relates to a casting tool for producing workpieces from light metal alloys. The system includes a positioning element, a core part, a first mold part structured to carry the positioning element and be movable toward the core part, and a core part support structured to support the core part. The system also includes at least one stop structured to limit movement of the front mold part toward the core part and to allow the positioning element to be introduced into the core part, whereby the positioning element holds the core part in a predetermined position for casting.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the following, the invention will be explained in even more detail by way of a preferred exemplary embodiment illustrated in the drawing, to which it is, however, not to be restricted. In detail, in the drawing:

FIG. 1 depicts a cross section through a part of a casting tool with a core part introduced therein;

FIG. 2 is a detailed view of a pin-shaped positioning element;

FIG. 3 is a schematic view of a casting tool for the production of a light-metal workpiece with the insertion of a core part resting on a core part support.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

FIG. 1 is a partial illustration of a casting tool 1 for the production of a light-metal rim 2, in which a core part 3 is provided, which has a lower density than the light-metal alloy cast around the core part. The core part 3 could, for instance, be comprised of a metal foam, in particular aluminum foam, or also of a compact made of a porous silicate material, e.g. vermiculite, or even of a steel ring or the like.

The casting tool 1 is substantially composed of a movable mold upper part 4 and a fixedly arranged mold lower part 5 as well as lateral core slides 6. The core slides 6 may, for instance, be comprised of four quarter-circularly shaped individual parts which are displaced from outside radially towards inside for abutment on the mold lower part 5 upon closure of the casting tool 1.

The mold upper part 4 includes a recess 4′, in which a pin-shaped positioning element 7, which is preferably made of steel, is fastened by the aid of an adhesive connection. The pin-shaped positioning element 7 serves to hold the core part 3 in a predetermined position within the casting tool 1 so as to enable the liquid light-metal alloy to be cast around the core part 3 as the former is being introduced into the casting tool. After having completed the casting procedure, the movably mounted mold upper part 4 is again displaced upwardly and the pin-shaped positioning element 7 is, thus, pulled out of the core part 3 and the light-metal alloy surrounding the core part. Because of the relatively small diameter of the pin-shaped positioning element 7, only a comparatively small opening will, thus, remain in the light-metal alloy 2 and in the core part 3, such that substantially smaller stress peaks will occur in the finished workpiece under load than with known positioning elements, which are fixedly positioned within the core part 3.

FIG. 2 depicts the pin-shaped positioning element 7 in detail. It is, in particular, apparent that a conical tip portion 8 is to simply penetrate into the core part 3. In the exemplary embodiment illustrated, an opening angle α of about 20° is provided.

The tip portion 8 is joined by a cylindrical portion 9 which, as is apparent from FIG. 1, is also received in the interior of the core part 3 in the position penetrated into the core part 3. In order to keep the stress peaks of the light-metal workpiece as low as possible after the removal of the positioning element, the cylindrical portion 9 has a diameter as small as possible. A diameter of about 1.6 mm is provided in the illustrated exemplary embodiment.

The cylindrical subportion 9 is joined by a conical subportion 10 having an opening angle β of about 10°. As is apparent from FIG. 1, this conical subportion 10 is surrounded by the light-metal alloy during the casting of the light-metal workpiece and removed from the former upon completion of the workpiece.

The conical subportion 10 is joined by a fastening portion 11 via a step-like diameter expansion, wherein the fastening portion is intended to be received in a recess 4′, of the casting tool 1. In order to provide for a simple introduction into the recess 4′ as well as a certain frictional engagement between the fastening portion 11 and the recess 4′, the fastening portion 11 is designed to be slightly conical. The fastening portion 11 is then joined by an end portion 12, which has a smaller diameter than the fastening portion 11 such that an adhesive will be able to reliably penetrate between the end portion 12 and the recess 6 of the casting tool 1.

FIG. 3 depicts a schematic view of the casting tool 1, wherein a carrier 14 capable of being vertically displaced in the sense of arrow 13 and immersibly mounted in the mold lower part 5 is to be seen, in particular. A plate-shaped core part support 15 is resiliently mounted on the carrier 14 in order to compensate for possible unevennesses during the lowering of the mold upper part 4. Column-shaped stops 16 are provided on the core part support 15 and, during the reception of the core part 3, serve to adjust the desired distance relative to the mold upper part 4, which is pushed down by a carrier plate 17. When designing the height of the stops 16, a measure is adjusted such that the pin-shaped positioning elements 7 (as illustrated in FIG. 1) will reliably penetrate into the core part 3, i.e. “impale” the core part 3, in order to hold the core part 3 in a predetermined position within the closed casting tool 1 after having lowered the carrier 14 and the core part support 15.

In an end region 18 flanged to the mold upper part 4, ejection pins 19 are provided in a conventional manner for the separation of the light-metal workpiece from the mold upper part 4.

In the preferred exemplary embodiment, reference was, thus, made to the production of a light-metal rim. It goes without saying that the casting tool according to the invention may, however, also be employed for the production of any other light-metal workpieces with core parts remaining in the cast workpiece. For instance, it may be employed in the production of wheel suspensions, longitudinal and transverse links, subframe parts, various types of braces and the like.

Claims

1.-20. (canceled)

21. A casting tool for producing workpieces from light metal alloys comprising: a positioning element;a core part;a first mold part structured to carry the positioning element and be movable toward the core part;a core part support structured to support the core part; andat least one stop structured to limit movement of the first mold part toward the core part and to allow the positioning element to be introduced into the core part, whereby the positioning element holds the core part in a predetermined position for casting.

22. The casting tool of claim 21, wherein the core part support is structured to be removable from the casting tool.

23. The casting tool of claim 21, further comprising a second mold part, which is structured to be movable relative to the first mold part.

24. The casting tool of claim 21, wherein the core part support is removable.

25. The casting tool of claim 23, wherein the positioning element is pin-shaped and tapers towards a free end, wherein the free end is arranged to be fixed in at least one of the first mold part and the second mold part.

26. The casting tool of claim 21, wherein the workpieces are produced for use in motor vehicles.

27. The casting tool of claim 21, wherein the core part is preformed.

28. The casting tool of claim 23, wherein the core part support is immersibly arranged in the second mold part.

29. The casting tool of claim 27, wherein the second mold part is fixably located.

30. The casting tool of claim 21, wherein the movable core part support includes the at least one stop, which limits forward movement of the first mold part.

31. The casting tool of claim 23, wherein the core part support is resiliently mounted on a carrier.

32. The casting tool of claim 31, wherein the carrier is displaceably mounted in guides of at least one of the first mold part and the second mold part via at least one centering pin.

33. The casting tool of claim 21, wherein the positioning element is structured to be at least partially conical.

34. The casting tool of claim 21, wherein the positioning element comprises a conical tip.

35. The casting tool of claim 34, wherein the conical tip is arranged to have an opening angle between 10° and 30°.

36. The casting tool of claim 35, wherein the conical tip is arranged to have an opening angle of substantially 20°.

37. The casting tool of claim 34, wherein the positioning element further comprises a cylindrical subportion arranged to follow the conical tip.

38. The casting tool of claim 37, wherein the cylindrical subportion has a diameter smaller than 3 mm.

39. The casting tool of claim 37, wherein the cylindrical subportion has a diameter smaller than 2 mm.

40. The casting tool of claim 37, wherein the cylindrical subportion has a diameter of substantially 1.6 mm.

41. The casting tool of claim 37, wherein the positioning element further comprises a conical subportion arranged to follow the cylindrical subportion.

42. The casting tool of claim 41, wherein the conical subportion has an opening angle of between 5° and 15°.

43. The casting tool of claim 41, wherein the conical subportion has an opening angle of substantially 10°.

44. The casting tool of claim 41, wherein the positioning element further comprises a fastening portion structured to have a larger periphery than at least one of the cylindrical subportion and the conical subportion.

45. The casting tool of claim 44, further comprising a recess, wherein in a fastened state, the fastening portion is structured to be received in the recess.

46. The casting tool of claim 44, wherein the fastening portion tapers slightly conically to the end of the positioning element, which is located opposite the conical tip portion.

47. The casting tool of claims 23, further comprising a recess wherein the positioning element is fixably positioned in the recess in one of a frictionally engaged manner or via an adhesive connection.

48. A method for producing workpieces from light-metal alloys, comprising: supporting a core part with a core part support;moving a first mold part having a positioning element towards the core part;introducing the positioning element into the core part as far as allowed by a stop arranged to limit movement of the first mold part, whereby the positioning element frictionally engages the core part;removing the core part support; andcasting the workpiece while the core part is held by the positioning element in a predetermined position.

49. The method of claim 48, wherein the core part has a lower density than the light-metal alloy.

50. The method of claim 48, wherein the core part has a higher density than the light-metal alloy.