DE7928167U1 - MOLDING TOOL - Google Patents

Description

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- 1 molding tool .

The innovation relates to a molding tool for the production of casting molds in loose molding materials in one of the known ones Molding process for the casting of castings with back cuts, especially of ring-shaped workpieces such as sliding and / or counter rings of mechanical seals.

Molds for the production of castings, which cuts have so far not been able to be produced by simple compression molding processes. Such forms are made

It is based on relatively complicated molding processes, such as the lost wax process, casting with lost models, or casting molds with inlaid cores are used. Likewise, undercuts can also be ground out of the cast blank at a later date.

For example, a mechanical seal has a ring-shaped undercut on the upper edge of its outer circumference extending retaining collar for an elastic O-ring. In production, this retaining collar is made from the corresponding larger cast ingot ground out.

The manufacture of articles with undercuts on these types are very laborious and expensive. There are additional tools, sometimes expensive materials and time-consuming Operations required, so that in particular mass production of such articles is uneconomical.

It is therefore the task of the present innovation to create a molding tool with which shapes can be made in a simple Molding process in loose molding materials for casting

of articles which have undercuts can be produced economically, so that mass production is also possible. The mold should preferably be used for the production of molds for the casting of sliding - and / or counter rings of mechanical seals made of cast iron or Steel with a retaining collar for an elastic O-ring on the outer periphery can be used as an undercut.

According to the innovation, this task is accomplished by a molding tool

solved, which is accordingly elastically deformable in the area of the undercuts of the casting. When this molding tool is pressed into the loose molding material during the molding process, the elastic area is so compressed by the resistance of the loose molding material. that forms the required undercut mold cavity arises. When relieving the tool, the elastic molded part goes back to its original shape, so that the formed undercut mold cavity is not destroyed when pulling out.

The design of the molded part depends on the size and position of the undercut mold cavity to be formed. she must be determined empirically by form tests. If necessary, by using auxiliary models in the molding tool the pressure of the loose molding material on the elastic molding can be increased so that the deformation in the desired direction is increased.

Since the innovation is mainly on forming tools for the manufacture of molds for the casting of sliding and / or counter rings of mechanical seals in mass production, the undercut of which has a retaining collar on

The upper edge of the outer circumference is elastic Deformable mold part from an annular support preferably made of an elastomer on the upper edge of the mold. By choosing the elastomer quality and shape of the Cross-section in connection with the non-elastic base body of the molding tool can be unilateral or double-sided undercuts are formed.

The mold according to the invention can, however, also be used for the production of casting molds for the casting of castings can be used with undercuts in other areas. Are the undercuts in the middle area of the casting, the middle part of the casting tool is accordingly designed to be elastically deformable. 15th

The innovation thus creates a molding tool with which loose molding material is extracted in the compression molding process Have molds made for casting castings with undercuts. In particular, the innovation is a economical mass production of ring-shaped articles such as sliding and / or counter rings for mechanical seals or piston rings, valve seat rings, etc. possible.

The innovation will be explained in more detail with the aid of some exemplary embodiments and the associated drawings shows

Figure 1 the cross section through a part piece a molding tool in the pressed and uncompressed state for the production of a sliding ring for a mechanical seal Figures 2-4 other forms of execution

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tools

In Figure 1, 1 is the cross section through a part of the innovation according to the mold with a rigid mold part 2 and an attachment 3 made of rubber with approximately pointed angular cross-section. At rest - or in tension

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tensioned state, i.e. when clamped in the molding material

Ί pressed state, the edition is 3 except for the dashed

Line 5 compressed. As a result of the incompressibility of the rubber material, a bulge that is directed radially outwards is created, which forms the undercut.

In Figure 2, the support 3 is made of rubber in a recess

of the rigid molded part 2 partially embedded in such a way that the support 3 is deformed outwards into the mold 9 when it is pressed onto the line 8. The line 8 coincides with the upper edge of the rigid molded part 2, so that a defined compression of the support 3 is achieved. 20th

In Figure 3, the molding tool 1 has a model insert 10, which, through its shape, ensures that the loose molding material is pressed in the direction of the support 3 during the pressing-in process and presses it outwards into the mold 11.

25th

In Figure 4, the support 3 has an approximately rectangular cross-section with slightly concave outwardly curved flanks

flat. By pressing together on the line 12, the support 3 is deformed and arched, as by her Form 13 shown, on both sides inwards and outwards, so that an undercut arises in the finished casting on both sides on the inner and outer circumference.

Claims (1)

Protection claims: j 1. Mold for making casting molds loose molding materials in one of the known molding processes, in which the final compression of the molding material is achieved by pressing, for the casting of castings with undercuts »in particular from ring-shaped workpieces such as sliding and / or Counter rings of mechanical seals, characterized in that the molding tool (1) is in the area of the Undercuts is elastically deformable. . Mold according to Claim 1, characterized in that that the elastically deformable area (3) from an elastomer body. κ 3 > Forming tool according to claims 1 and 2, characterized in that the elastically deformable area (3) of the forming tool (1} consists of an elastic support. . Mold according to Claims 1 to 3, characterized in that the elastic support (3) is in a recess (7) of the molding tool (1) is incorporated. . Mold according to one of Claims 1 to 4, characterized in that the mold (1) has at least one insert (10) which compresses the loose molding material so that the deformation of the elastically deformable molded part (3) is reinforced in the desired direction.