EP0114570A2 - Device for the extrusion of a hollow section - Google Patents

Abstract

A method for extruding a bolt provided in a transducer, in particular made of light metal, into a hollow profile through the shaping cross section of a die, to which a mandrel determining the inner contour of the hollow profile is assigned, and a device with a press ram for extrusion are to be equipped in such a way that the one-piece production of Flange pipes is possible. The result of this is that a flange which is integral with it is produced on the hollow profile during the pressing process and is preferably produced at the end of the pressing process. In the extrusion press suitable for this purpose, a molding cavern (30), the radial extension (b) of which is greater than the width of the molding cross section, is directly connected upstream of the shaping cross section (23) in the die (20 in the pressing direction (x). radially to the pressing direction (x) can be separated into at least two die parts (20a, 20b).

Description

The invention relates to a method for extruding a bolt provided in a transducer, in particular made of light metal, into a hollow profile through the shaping cross section of a die, which is assigned a mandrel that determines the inner contour of the hollow profile. In addition, within the scope of the invention is an apparatus for extrusion with a ram.

A device of this type and a corresponding method are described in US Pat. No. 3,240,047, specifically on a welding chamber tool which carries several fixed mandrels on a bridge part, the shank of which is surrounded at a distance by a tool ring.

With this tool, it should be possible to produce pipes that have so-called pressure weld seams in the pressing direction, that is to say that they do not have a perfect structural cross section.

There are applications for pipes or the like. Hollow profiles, in which not only the hollow tubular shaft must be seamless, but also a flange to be provided at the pipe end should be connected as far as possible without changing the structure. Such an application arises, for example, for so-called recipients of uranium separation plants; these recipients consist of a tubular body with a flange connected at one end. The latter is usually welded on and reworked.

In view of these circumstances, the inventor has set itself the goal of producing a hollow profile with a flange attached in one piece in a cost-effective manner.

To solve this problem leads to the fact that during the pressing process on the hollow profile a one-piece flange is produced, preferably at the end of the pressing process from the part of the bolt remaining after the extrusion of the hollow profile in a mold cavern. Then, according to a further feature of the method according to the invention, the hollow profile arranged downstream of the flange in the pressing direction is to be led out of the die in this pressing direction.

Thanks to these requirements, a seamless and one-piece flange tube, preferably made of light metal, is created, which meets increased strength requirements and can be produced in a single operation, avoiding the bolt part that remains after the bolt has been formed and is to be sheared off.

Within the scope of the invention is a device of the type mentioned, in which a molding cavern is connected directly upstream of the shaping cross section on the die in the pressing direction, the radial extent of which is greater than the width of the shaping cross section and in which the compressed matrix laterally over the hollow profile cantilevered flange forms.

It has proven to be particularly advantageous to mold the cavity into the die front facing the block receiver, so that the die forms both the hollow profile and the flange attached to it in its entire height. However, it is also possible to associate this molding cavern with an indentation that extends it against the pressing direction in the subsequent transducer face, which appears to be particularly useful if flanges of great height are to be produced.

The removal of the finished hollow profile with flange from the extrusion press is carried out according to the invention in the pressing direction, for which purpose the die is separated radially into at least two die parts and the surfaces delimiting the shaping cross-section - primarily formed in part-ring shape - are arranged such that they can be moved with respect to one another with the die parts. The divided surfaces delimiting the shaping cross-section can be moved apart by an amount forming a gap which is larger than the corresponding extension of the flange, so that the latter can be extended by the tool or the die.

If the flange is polygonal, the parting surfaces of the die parts - and possibly the parts of a tool holder holding these die parts - run diagonally through the flange plan, i.e. through two of the floor plan corners. These corners preferably determine vertical dividing surfaces, which allows the die parts to be moved laterally.

Moreover, according to the invention, each of the die parts sits in a corresponding part of that multi-part tool holder.

The radially divided die is held together during the pressing process by a surrounding pressure ring, which in the context of the invention either represents a separate machine part or is formed by the block receiver.

For this purpose, it has proven to be advantageous to chamfer the end of the die near the block receiver or to provide it with a truncated cone surface onto which the pressure ring or the block receiver then having a corresponding recess is pushed. The pressure ring or block sensor are of sufficient strength to absorb all radial forces during the pressing process.

The advantage of the conical connection surfaces between the die and the block receiver or pressure ring is that the axial connection is easy to produce and can be interrupted again.

Since the contours of the molded cavern determine the shape of the flange, it is also possible, for example, to design it with ring ribs or the like if there are corresponding grooves in the cavern floor.

Overall, thanks to the invention, there is now the possibility of extruding flange tubes made of aluminum, which was previously not possible in the simple manner described.

• Fig. 1 den horizontal gelcgten Längsschnitt durch eine Strangpresse während des Herstellens eines Hohlprofiles;
• Fig. 2 einen vergrößerten Ausschnitt aus Fig. 1;
• Fig. 3 einen Teilschnitt durch Fig. 2 nach deren Linie III - III;
• Fig. 4 eine der Fig. 2 entsprechende Wiedergabe eines Teiles der Strangpresse in einer anderen Betriebsstellung;
• Fig. 5 einen Teilschnitt durch Fig. 4 nach deren Linie V - V;
• Fig. 6,7 einen Teil der Fig. 2 entsprechende Darstellungen anderer Ausführungsformen.

Further advantages, features and details of the invention result from the following description of preferred exemplary embodiments and from the drawing; this shows in

• Figure 1 shows the horizontal longitudinal section through an extruder during the manufacture of a hollow profile.
• FIG. 2 shows an enlarged detail from FIG. 1;
• 3 shows a partial section through FIG. 2 along the line III-III;
• FIG. 4 shows a representation of a part of the extrusion press corresponding to FIG. 2 in another operating position;
• 5 shows a partial section through FIG. 4 along the line V - V;
• 6, a part of FIG. 2 corresponding representations of other embodiments.

From the press cylinder 1 of an extrusion press 2 for the production of hollow profiles 3 of an outside diameter d, a hollow press ram 4 projects into a bore 5 of a block receiver 6 according to FIG. 1 9 in - not shown - rest position of the press ram 4 is dimensioned such that in this rest position of the transducer bore 5, a hollow bolt B made of light metal can be placed through a loading carriage 11. If the pin axis A is coaxial to Press axis E aligned, the bolt B is inserted by the press ram 4 in the pressing direction x into the sensor 6.

In the press axis E there runs a horizontal mandrel column 14 of an outer diameter e passing through the bore 12 of the hollow press ram 4 and the hollow bolt B, which in the selected exemplary embodiment rests displaceably in bearings 15 of a piston 16 of the press cylinder 1. The piston 16 is actuated by piston rods 17.

On the pick-up face 18 remote from the press cylinder 1, a die 20 is seated in a tool holder 19 as a molding tool. The tool holder 19 is supported against a crosshead 21 at the press exit.

4, 5 in particular, tool holder 19 and die 20 are divided on the vertical diameter D of the circular shaping cross section or die opening 23 and can be moved apart in the radial direction z; the shaping cross section 23 thus limit two half rings 24, 24 _a . From these, an outlet channel 25 widens conically to a through opening 26 of the crosshead 21.

In the pressing direction x, an indentation 30 lies in front of the die opening 23 in the die 20, the greatest width _{b of which is} slightly larger than the diameter f of the receiver bore 5. The side walls 31 of this indentation 30 delimit an almost square outline according to FIG. 3 and are one Embodiment curved (31 _a in Fig. 5). The pitch diameter D forms a diagonal through two mutually opposite molding corners 32, which are thus located on the tearing surfaces 33 of the die 20. With these aligned parting surfaces 34 of the multi-part tool holder 19. The parting surfaces 34 of the tool holder parts 19 _a , 19 _b in FIG. 5 have centering strips 3G on the one hand and centering grooves 39 receiving this in a closed position on the other hand.

This indentation 30 takes up a part of the matrix 8 ₁ emerging from the bolt B, which is formed into the hollow profile 3 during the pressing process. This consists of a tubular part 35, the inner contour of the mandrel column 14 and the outer contour of the half rings 24, 24 _{a of} the die opening 23 are determined, and a flange 36 integrally formed therewith with a height i. This flange 36 arises from the baling residue of the matrix B ₁ . The distance of this flange 36 from the side walls 31 of the indentation 30 is shown exaggerated in FIG. 3.

The flange 36 can be removed after pressing the bolt B completely and moving the die halves 20 _a and 20 _b (FIG. 5) between them in the pressing direction x. Before the extruded hollow profile 3 is pulled off, the mandrel column 14 is retracted, flange corners 36 _{e being supported} against the transducer face 18.

In order to ensure that the separating surfaces 33 of the die halves 20 _a , 20 _b lie against one another during the pressing process, the die 20 extends in the pressing direction x from its die front 40 to form a truncated cone-like closing pressure surface 41 of a length n up to an annular surface 42, which is a shoulder-like ring shoulder 43 follows; the latter abuts an annular rib 44 of the tool holder 19.

In the closed pressing position of the die 20, the closing pressure surface 41, which is inclined at an angle w of, for example, 15 ° to the press axis E, encloses an approximately parallel pressure wall 49 of a central recess 50 of the one-piece block receiver 6, as is particularly clear from FIG. 4.

Instead of that pressure wall 49, the closing pressure surface 41 can also be encompassed by a closing ring 51, which abuts a nose 52 of the die 20 and whose thickness h corresponds at least to the height i of the flange 36.

An embodiment of FIG. 7 is produced thanks to a shaped groove 45 of the die 20, delimited by a shaped rib 46, a flange 36 with a circumferential rib 37, the flange 36 projecting over the die front 40; the projecting flange part is formed in a shaped cavity 54 of the transducer face 18, to which the central transducer opening 50 connects in the pressing direction x.

Thanks to this device 2, it is now possible to press flange tubes 3 in one piece, which can be used, for example, as recipients for centrifuges of uranium separation systems. The floor plan of the flange 36, which is determined by the indentation 30, is freely selectable, as is the diameter d of the flange tube 3. It is also up to the respective circumstances whether conventional hollow bolts B are used or these are tempered beforehand. The device for solution annealing of the bolt B is not shown in the drawing.

According to the patent application P 28 12 690.1, the mandrel column 14 can be designed to move along or be a fixed part of the press ram 4.

Claims (10)

1. A method for extruding a hollow profile from a bolt or block, in particular from light metal, which is brought up in a block receiver to the shaping cross section of a die and inserted into it by means of a pressing force, the shaping cross section determining the outer contour of the hollow profile and a mandrel determining the inner contour thereof,
characterized,
that at the end of the pressing process for the hollow profile, a one-piece flange is pressed against it. 2. The method according to claim 1, characterized in that after the filling of the outer contour of the flange-defining cavity, the extrusion process is interrupted and the flange downstream in the pressing direction of the die is optionally removed in the pressing direction. 3. Device for the extrusion of a hollow profile from a bolt or block, in particular made of light metal, which is brought up in a block receiver to the shaping cross section of a die and is inserted into it by a press ram, the shaping cross section determining the outer contour of the hollow profile and a mandrel determining the inner contour thereof characterized in that the shaping cross section (23) on the die (20) in the pressing direction (x) has a shape cavern (30) is directly upstream, the radial extent (b) is greater than the width (d) of the shaping cross section. 4. The device according to claim 3, characterized in that the molded cavern (30) is molded into the die front (40) directed towards the block receiver (6) or the die part containing the molded cavern is detachable from the die (20). 5. Apparatus according to claim 3 or 4, characterized in that the die (20) is separated radially to the pressing direction in at least two die parts (20 _a , 20 _b ) and the shaping cross-section (23) delimiting surfaces (24, 24 _a ) with the die parts are arranged to be movable relative to one another, where appropriate these surfaces which delimit and divide the shaping cross section are attached to form a gap which can be moved apart by an amount which is greater than the corresponding extent (b) of the flange (36). 6. Device according to one of claims 3 to-5, characterized in that the side walls (31) of the cavity (30) are polygonal in plan and the position of the parting surfaces (33) of the die parts (20, 20 _b ) of two plan corners (32 ) the mold cavern is determined, the separating surfaces preferably being placed vertically through the shaping cross section (23). 7. The device according to at least one of claims 4 to 6, characterized in that the parts (20 _a , 20 _b ) of the die (20) sit in a correspondingly divided, separable tool holder (19) and / or the die in a pressed position extensive pressure ring (6, 51) is assigned. 8. The device according to at least one of claims 3 to 7, characterized in that the die (20) tapers against the pressing direction (x) at least. In an area close to the die front (40) and this conical area (41) in the pressure ring (6, 51) can be used, which is preferably provided at least axially displaceable. 9. The device according to claim 7 or 8, characterized in that the block receiver (6) is designed as a pressure ring and has a recess (50) facing the die (20) for receiving the conical die region (41), and / or that the conical Surfaces (41, 49) on the die (20) or pressure ring (6, 51) are inclined at an angle (w) of approximately 5 to 15 ° to the pressing direction (x). 10. The device according to at least one of claims 4 to 9, characterized in that in the bottom of the mold cavern (30) of the die (20) form channels (45) are introduced, and / or that the mold cavern one against the pressing direction (x ) lengthening recess (54) is assigned in the subsequent transducer face.

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