DE3001671A1 - DIE FOR SOLID FORMING IN THE COLD OR SEMI-WARM PROCESS - Google Patents

Description

The invention relates to a die for massive forming; in the cold or warm process from a shrink bandage with an interior space, if necessary Longitudinally divided die core and one or more shrink rings.

With the mentioned cold or warm processes for the production of mass parts from metal or plastic creates high pressures of up to 30,000 bar = such matrices, The tools for the production of mass parts can be used on single or multi-stage presses Type to be used =

In general, a shrink bandage consists of a die core and at least one shrink ring = A as a pressure transducer Serving die core can have a smooth or a stepped round or polygonal interior. As a result of the shrinkage, the die core becomes tangential Prepress

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tension and a tangential tensile prestress in the shrink ring generated. The working pressure then has the effect that a tangential tensile stress is generated in the die core, which counteracts the previously applied tangential compressive prestress. Of the relationship between the two tensions depends on the compressive strength of a die core. The compressive prestress on the inner surface of the die core is useful greater than the tensile stress created under the working pressure.

This can be met in that the die core is pretensioned in the shrink fit in such an amount that it is constantly remains under the compressive stress mentioned. In this case, however, there is the problem of overloading at least one a shrink ring, because there is preload on its inner diameter and add working voltage. If the resulting value is so high that its plastic deformation of the Shrink ring takes place, the die core tears when starting Work pressure.

It can be assumed that the die core is radial and tangential Stresses arise, whereby the tangential stresses act as tensile stress under the working pressure, which is best, to pull apart the die core and which are also supported by them through the radial compressive stress. Input Mentioned longitudinally split die kinks:? ne are used when there is a certain change in cross-section in common cold-pressed steels Exceed value or if a relatively large shoulder opening angle is required. It is about but about two cylindrical components made of the same material, which are closed around their circumference. The same also applies to Constructions with double-reinforced die core.

The invention is based on the object of providing a die of the initially mentioned specified type, with the same dimensions as known matrices, a higher stability or durability

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has resilience, "or», if they are based on appropriate labor values as known matrices are designed, with smaller dimensions and at least in part also with less expensive Material can be produced = Here, taking into account the above advantages, the exchange should also be possible of a die core are facilitated »

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ORIGINAL

It is known that die cores made of tungsten carbide (hard metal), Manufacture high-speed steels or ledeburitic chrome steels. All of these materials can only be accepted to a very limited extent in the operational state (for steel with a hardness of 52-64 Rockwell C) suitable for tensile stresses.

The materials for the shrink rings are alloyed tool steels or martensite-hardening nickel alloys.

The use of these materials is included in the practice of the invention. The result is that straight In the case of the specified materials for die cores, a considerable preload is required in order for the resultant to occur To keep tensile stresses within limits.

The object is achieved in that a between the die core and at least one shrink ring arranged intermediate bush made of a material of high compressive strength and has at least two spaced apart, essentially axially extending slots.

This results in an adaptability of the intermediate socket in the sense of the tangential stresses, so that the tendency to crack formation on the outside of the die core, a means is opposed in that at this point a means in the sense of the tangential stresses compliant component is introduced. The at least two spaced-apart slots represent the Adaptability in the above sense, because under the pressures occurring also the radial stresses that are due to the Circular shape can be converted into tangential stresses due to the given flexibility of the slots in the area of the intermediate bushing be included. If at least two spaced slots are mentioned, it is understood that the use of more slots is preferred.

Furthermore, there is an advantageous comparison of a known shrink fit with a die core and at least one shrink ring Design in that a known die core is divided in terms of its radial dimension or its wall thickness is in an internally arranged core of reduced wall thickness and the slotted intermediate bushing. The intermediate socket is advantageous

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made of tool steel, the high compressive strength has * This results from the fact that the circumferential flexible Intermediate socket practically only transmits radial stresses.

In an advantageous embodiment, it is preferred that a very thin-walled core made of hard metal or high-speed steel depending on the size of the hole from 2 to 1omm is used. Furthermore, the shrink ring itself can be smaller or, as already, noticed, can be made from a cheaper material.

In an advantageous embodiment, there are at least two. Slots arranged continuously and the intermediate socket is in Subdivided cylinder wall sections = This results in cylinder wall sections that can move relative to one another over their length =

In another advantageous embodiment, the slots are different Starting from the front edges of the bushing alternately

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arranges and up to the trouble of the other letter irnr of the guided. This in itself becomes an intermediate socket in the solid. Association with regard to the scope created, but a discharge of tangential stresses over the entire length of the intermediate bushing enables.

According to another advantageous embodiment, all the slots start from a socket front edge and end at a distance from the other end of the bushing = this design offers the particular possibility of partially applying a higher preload generate, which is particularly advantageous for die cores with a separate interior.

An expedient embodiment has three slots or pairs of slots. However, it is preferred to arrange more slots, for example eight slots. Through the majority of the slots is

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the described effect of the slotted inner sleeve increases.
In the usual way, a cylindrical design of the joints between the core and the Zxirischenbuch.se on the one hand or the intermediate bushing and the shrink ring on the other hand is included. A conical design of the parting lines is not excluded and

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can with regard to the execution of the interior of the The die core can be useful if there are special gradations or profiles over the longitudinal direction »

If it is also possible "to first insert the intermediate bushing into a shrink ring during manufacture and then shrink the die core into this yerband, it is preferred to first insert the core into the intermediate bushing during manufacture and then these two parts together in a shrink ring arrangement to shrink _o This is advantageous ρ if the die core is to be replaced later »

The invention is explained below with reference to exemplary embodiments which are shown in the drawing »

Show in the drawing

FIG. 1s a side view of a die in a shrink fit in the cut

Figure 2S is a perspective view of the intermediate bushing used in the embodiment in Figure 1 »

FIG. 3 § a representation corresponding to FIG. 1

other embodiment "

Figure 4s in a perspective view of the intermediate

socket for the version according to Figure 3 »

Figure 5 ° in a perspective view another

Design of an intermediate _{socket o}

Figure 6a and bs representations of a known die and a

according to the invention designed die for explanation of economic advantages,

According to FIG. 1, a die core 1 with a separate interior space is arranged within an intermediate bush 3 in a shrink ring k . The intermediate socket 3 & at, starting from its upper socket end edge 9 in FIG. 2, has eight slots 5 "6 ₉ 7, .."""

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have a groove at their end to avoid tension can. The slots extend parallel to the longitudinal axis of the socket and radially penetrate the socket wall.

According to Figures 3 and 4 it can be seen that a relatively thick-walled cylindrical die core 10 is arranged in an intermediate bush 11 within a shrink ring 4. These Intermediate bushing 11 is through from the upper edge of the bushing 9 to to the lower socket end edge 8 continuous eight radial slots 12, 13 »14, ... divided into cylinder wall sections 15» 16, 17 ». · ♦.

From Figure 5 it can be seen that an intermediate sleeve 18 from the upper Socket end edge 9 starting from diagonally opposite slots 19 »20 occupied, those at a distance from the lower socket front edge 8 ends. Another pair of slots 21, 22 is arranged offset by 90 ° from the lower socket end edge 8, the Slots spaced from the upper edge of the socket 9 end up. This results in an adaptability over the entire height or length of the intermediate sleeve without the association the intermediate bushing is interrupted.) If parting lines are mentioned are, then these are the adjacent surfaces the outside of a core and the inside of an intermediate socket or the outside of an intermediate socket and the Inside of at least one shrink ring. In the exemplary embodiments, cylindrical shapes are shown for the parting lines. Conical configurations are included, with the possibility that one or more of the parts in the association of the Tool has a cross-section that changes over its height.

A comparison of the embodiments in FIGS. 6a and 6b shows that, for example, when the die core 1 with the same wall thickness through the use of an intermediate bush 3, the shrink ring 4, as shown in Figure 6b at 4, with a smaller Wall thickness can be run.

If the shrink ring 4 should keep its wall dimensions, it can be made of cheaper material or this is also the case when the slotted intermediate bush 3 is inserted

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with dimensions corresponding to 4 possible »

Accordingly, there is also the possibility _g by the use of the slotted intermediate sleeve the thin-walled die core and thus perform less expensive =

Here it must also be taken into account ₉ that in an embodiment ₉ in which the inner diameter of the intermediate sleeve is small compared to the outer diameter of the intermediate _{sleeve 9} the radial pressure _s resulting from the shrinkage pressure and the working pressure ₉ with a correspondingly smaller ¥ ert on the reinforcement ₉ that is . affects the shrink ring assembly. This results in a reduction according to the ratio of the inner diameter to the outer diameter. Because the intermediate bushing itself remains practically free from tangential stresses due to the slots, it is possible, with the same inner diameter of the inner roughness of the die core or the same outer diameter and inner diameter of the shrink ring as before " either to put a higher preload on the die core or to relieve the shrink ring or the shrink ring arrangement accordingly »

It goes without saying that the intermediate bushing according to FIG. 6b is practical is carried out like the intermediate bushing 3 in FIGS. 1 and 2.

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Claims (8)

Claims Die for massive forming in the cold or warm process from a shrink fit with an interior , possibly longitudinally divided die core and one or more shrink rings, characterized in that an intermediate bushing (3, 11, 18) made of a material with high compressive strength in axial direction; has at least two mutually offset slots (5-7, 12-14, 19-22). 2. Die according to claim 1, characterized in that a known The die core is divided in terms of its wall thickness into an internally arranged core (1) Wall thickness and the slotted bushing (3) ° 3. Die according to claim 1, characterized in that when executing the die core (1) with constant wall thickness one opposite a known shrink ring (4) in the Wall thickness reduced shrink ring (4) and a slotted bushing between the die core (1) and shrink ring (4) (3) is arranged. 130030 ^ 0440 BATH. ORIGINAL -z- 4. Die according to one of claims 1 to 3, characterized in that that at least two slots (12-14) are arranged continuously and the intermediate sleeve (11) in cylinder wall sections (15-17) is divided. 5. Die according to one of claims 1 to 3> characterized in that slots (19-22) starting from different end edges (8, 9) are arranged alternately and up to the vicinity of the other socket front edge performed are. 6. Die according to one of claims 1 and 3 _? characterized in that all slots (5-7) start from one socket end edge (9) and end at a distance from the other socket end edge (8). 7- die according to one of claims 1 to 6, characterized through a cylindrical design of the joints. 8. Die according to one of claims 1 to 6, characterized by a conical design of the parting lines. 130030/0440 BATH ORIGINAL