WO2019001635A1

WO2019001635A1 - Bridge tool for producing extruded profiled elements of varying cross-section

Info

Publication number: WO2019001635A1
Application number: PCT/DE2018/100586
Authority: WO
Inventors: Sören Müller; Maik NEGENDANK; Vidal SANABRIA
Original assignee: Technische Universität Berlin
Priority date: 2017-06-28
Filing date: 2018-06-26
Publication date: 2019-01-03
Also published as: EP3645183B1; EP3645183A1; US20200147661A1; CN110891704B; CN110891704A; DE102017114371A1

Abstract

The invention relates to a bridge tool for a device for directly extruding hollow profiled elements of variable wall thickness, comprising a die (6) and at least one mandrel element (5) having a first end facing the die opening and an opposite second end, the outer profile contour of a hollow profiled element being defined by the geometry of the die opening and the inner cross-section of a hollow profiled element being defined by the at least one mandrel element (5), characterized in that the at least one mandrel element (5) has at least one cut-out, in which an inner sliding mandrel is arranged, said inner sliding mandrel being mounted for movement in the axial direction, the inner sliding mandrel having different cross-sections in the first end region of the inner sliding mandrel facing the first end of the mandrel element.

Description

Bridge tool for producing extruded profiles with varying cross section

The present invention relates to a bridge tool for producing extruded profiles with varying cross-section.

Extrusion is a forming process for the manufacture of

different geometries, in particular of rods, tubes and profiles. In extrusion molding, a compact (block) heated to forming temperature is pressed with a punch through a die. The block is enclosed by a recipient. The outer shape of the pressed strand is determined by the die.

It is in the prior art between direct extrusion,

indirect extrusion and hydrostatic extrusion

distinguished.

In direct extrusion, the punch pushes the block along the inner surface of the recipient in the direction of the die. In indirect extrusion, the recipient is closed on one side, and from the other side is pressed onto the block, the die, which is located at the head of a hollow punch. The strand passes through the punch bore. Their diameter thus limits the circumscribing circle of the profile cross-section. In hydrostatic extrusion, the pressing force is not applied directly to the block by a die, but rather by an active medium (water or oil).

The advantages of extrusion are generally the low tooling costs and the variety of geometries that can be generated.

Complex hollow profiles made of light metal can by means of direct

Extrusion process via chamber or bridge tools are generated, wherein the bridge tools comprise a Matrizen- and a mandrel part. Here, the outer contour, as already stated, determined by the die and the internal shaping of the mandrel. The mandrel itself is not directly connected to the extruder, but via support arms or bridges with the mandrel part of the tool. In doing so, the block itself first passes through the into the mandrel part

introduced inlet chambers split into sub-strands and then reconnected in the welding chamber of the die under high pressure and temperature.

In bridge tools occur while extreme mechanical and

thermal stresses, in particular to the

Dorntragarmen are problematic. Cracking stresses at the roots of the spine can also cause cracking.

A disadvantage of the known from the prior art

Extrusion is that only profiles with a constant

Profile cross section can be generated. As a result, the profiles are oversized in many places, since the profiles must always be formed in accordance with the requirements of the highest stress location over their entire length.

To produce varying cross sections in an extruder DE 10 02 18 81 A1 teaches a device for extrusion molding, in which a mandrel in the axial pressing direction formed changeable and having different cross sections in its end region. Depending on the arrangement of the end regions of the mandrel described there relative to the die, an annular gap with a different diameter is formed to form different profile cross sections.

[001 1] A disadvantage of a solution according to DE 10 02 18 81 A2, however, is that although a device comprising a chamber tool is disclosed, which should allow a varying cross-section of the extruded profile, but the entire mandrel, which has a large length for technical reasons, must be moved axially. The resulting long lever arms cause relatively large oscillations of the mandrel. However, such vibrations prevent production of profiles with high precision and tight tolerance requirements. Furthermore, it is disadvantageous that the durability of a mandrel according to DE 10 02 18 81 A1 is reduced. Such a mandrel is subject in use high thermomechanical stresses, which depend in particular on the occurring pressing forces and forming temperatures. Above all, the long Dorntragarm is exposed to alternating tensile and bending forces, which can be superimposed on local thermal stresses.

The object of the present invention is now to overcome the drawbacks of the prior art, and in particular to provide a device to produce profiles with a variable profile cross-section with high precision, since only with such a high precision over-dimensioning of the profiles effective can be avoided, wherein the device is designed and set up so as to optimally to the thermo-mechanical stresses

resist.

This object is achieved by a bridge tool for a device for direct extrusion of hollow profiles with variable wall thickness, comprising a die and at least one

Mandrel element with a die opening facing the first end and an opposite second end, wherein the outer

Profile contour of a hollow profile by the geometry of the die opening and the inner cross section of a hollow profile by at least one

Mandrel element is fixed, wherein the at least one mandrel element has at least one recess in which is mounted movably mounted in the axial direction, an inner displacement mandrel, wherein the inner displacement mandrel in its first end of the mandrel element facing first end region has different cross sections.

The invention is based on the surprising finding that a generation of hollow profiles with varying inner diameter can be realized when the mandrel is built in several parts, with a movable inner displacement mandrel with different cross-sections is included at its end portions, the axial movement results in a change of the inner cross section of the hollow profile.

It may be particularly advantageous that the inner

Displacement mandrel has the smallest cross-section at its first end, so that an axial displacement of the inner displacement mandrel in the direction of the die or in the die to a lesser extent

Wall thickness of the hollow profile leads, since the forming gap between inner displacement mandrel and die is reduced.

The disadvantages of the prior art are overcome by the at least two parting of the mandrel. The inner displacement mandrel can by means of connecting elements via short lever arms with

Drive elements are brought into operative connection to allow the axial displacement of the same, so that vibrations of the mandrel are minimized. It may also be provided that vibrations of the inner displacement mandrel can be almost completely prevented by special guide elements.

The inner sliding mandrel according to the invention thus enables a

Production of hollow profiles with varying cross-section with high precision.

Movements of the inner displacement mandrel and other elements of the bridge tool according to the invention are relative to

Pressing direction designated. An axial displacement basically describes a displacement in the pressing direction or parallel to the pressing direction, a radial displacement a radial displacement relative to the pressing direction.

According to the invention it may be advantageous that the mandrel element

at least one second axial recess extending in the axial direction along the first end portion of the inner

Displacement mandrel opposite the second end portion of the inner displacement mandrel extends, wherein one, in particular almost, perpendicular to the at least one mandrel element arranged transverse slide comprises is that in the at least one second recess at least

is inserted in sections, and wherein the cross slide is in operative connection with the inner displacement mandrel, in particular firmly connected to the inner displacement mandrel.

A cross slide according to the invention can be used for transmitting a force from a drive device to the inner displacement mandrel, wherein the drive device preferably outside the actual bridge tool, for example, on the outer wall of the transducer or the holder of the bridge tool, can be arranged.

It may be particularly advantageous that the cross slide directly or by means of at least one cross member with at least one

Drive device is engageable or can be brought, wherein the drive device is designed and arranged to move the cross slide and the inner displacement mandrel in the axial direction.

It may also be advantageous if a power transmission from the drive device to the inner displacement mandrel not only with the interposition of the cross slide, but if in addition between the drive means and the cross slide, a cross member is arranged.

Furthermore, it may be preferred that a first cross member is disposed at a first radial end of the cross slide and a second cross member at a second, the first radial end opposite radial end of the cross slide is arranged, wherein the first cross member with a first drive device and / or the second cross member with a second drive device in

Active compound can be brought or stands.

By using two at the opposite end of the

Cross slide arranged cross beams can be a uniform, parallel transmission of power from the drive devices on the inner displacement mandrel and at the same time tilting the same be prevented. Alternatively, it can also be provided that, instead of a second drive device, both cross members can be connected or connected to a single drive device.

It has proved to be advantageous that the first and / or the second drive device is designed in the form of a linear drive, in particular in the form of a hydraulic cylinder.

It has been shown that in particular hydraulic cylinder for a

Generation of a linear force have been found to be particularly suitable for an axial displacement of the inner displacement mandrel

enable.

Also, it may be advantageous according to an embodiment of the invention that the inner displacement mandrel in the region of its first end in the axial direction sections a trapezoidal or

has triangular cross-section.

The present invention is not limited to the exemplified trapezoidal or triangular cross-sections. Instead, their cross section is determined as a function of the number of movable displacement elements.

It may be provided according to an embodiment that the inner angle or pitch angle ß of the trapezoidal or

triangular cross-section a value in the range of 5 to 25 °, preferably from 8 to 15 °, particularly preferably of 10 °. The optimal angle can be, even outside of the preferred ranges,

According to the invention according to the drive or the available space to minimize the power requirement (small angle, long displacement) or to minimize the space (large angle, short displacement) adapted / selected.

It can also be advantageously provided that the inner displacement mandrel is at or in the region of its first end with at least one wedge-shaped element in operative connection or this in particular, the further pitch angle β of the inner sliding mandrel facing side of the at least one wedge-shaped element is less than or equal to the pitch angle ß, so that an axial displacement of the inner sliding mandrel in a

corresponding radial displacement of the at least one

wedge-shaped element is transferred.

According to the invention, in addition to the radially movable inner

Displacement mandrel for changing the inner cross section of a hollow profile to be used on at least one wedge-shaped element whose radial displacement relative to the inner displacement mandrel directly affects the wall thickness of the hollow profile.

It has proved to be advantageous according to the invention that a radial movement of the inner displacement mandrel in the direction or further into the die leads to a spreading movement of the at least one wedge-shaped element in the radial direction, since the smallest cross section of the inner displacement mandrel at its first end is arranged.

This has the particular advantage that the high forces that occur need not be absorbed exclusively by the inner displacement mandrel, but also by the at least one wedge-shaped element.

Furthermore, regardless of the geometry of the inner displacement mandrel, the inner cross section and the wall thickness of the hollow profile can be varied by a virtually free configurability of the at least one wedge-shaped element.

The wedge-shaped element according to the invention can be different

Have base surfaces and the acute angle of the wedge can be formed by two or more sides.

It has proven to be advantageous that at least a second

wedge-shaped element mirror-symmetrical to the first wedge-shaped

Element on the first wedge-shaped element opposite

Side of the inner displacement mandrel is arranged. An insert of two mirror-symmetrically arranged wedge-shaped

Elements makes it possible to simultaneously change the wall thickness on two sides of a hollow profile. It is obvious that more than 2 wedge-shaped elements can be used, which can be grouped radially around the inner displacement mandrel.

It has also been shown that, advantageously, the at least one

wedge-shaped element is connected by means of a first dovetail guide with the mandrel element, wherein the at least one first

Dovetail guide allows movement of the at least one wedge-shaped element exclusively in the radial direction, wherein the dovetail guide in particular of the

Mandrel element and the at least one wedge-shaped element is formed.

By a first dovetail guide according to the invention is

allows the at least one wedge-shaped element is movable only in the radial direction, but not in the axial direction. This leads in particular to an axial movement of the inner

Displacement mandrel leads with its varying in the axial direction of cross section exclusively to a radial movement of the at least one wedge-shaped element. Furthermore, tilting of the wedge-shaped element is prevented and reproducibility of the

Implementation of the axial movement of the inner displacement mandrel in the radial movement of the at least one wedge-shaped element

ensured.

According to one embodiment of the present invention, it has also proved to be particularly advantageous that the inner

Displacement mandrel and the at least one wedge-shaped element by means of a second formed in the axial direction

Dovetail guide are connected, so that an axial

Movement of the inner displacement mandrel is converted in a radial movement of the at least one wedge-shaped element. The second dovetail guide according to the invention offers the particular advantage that a secure connection between the inner displacement mandrel and the at least one wedge-shaped element is provided. Furthermore, the second dovetail guide is particularly advantageous because it not only ensures that, when the inner displacement mandrel moves in the direction of or into the die, there is a radial movement of the at least one wedge-shaped one

Elements to the outside, but also that in a reverse movement of the inner displacement mandrel tensile forces act on the at least one wedge-shaped element to the radial spread of the

reduce wedge-shaped element.

Furthermore, it can be provided that the first recess of the

Dorn element and the at least one inner displacement mandrel form a third dovetail guide in the axial direction, so that the inner displacement mandrel and the mandrel member by means of a

Dovetail guide are interconnected.

This has the particular advantage that tilting of the inner

Displacement mandrel is prevented even with a concern high forces.

The invention also provides a device for direct extrusion comprising a bridge tool according to the invention.

Finally, the invention provides a use of a

Bridge tool according to the invention for producing one or more extruded profiles with variable in the pressing direction

Cross sections in a device for direct extrusion. The invention is therefore based on the surprising finding that a change in the profile wall thicknesses during extrusion while avoiding the disadvantages of the prior art can be achieved in that an inner displacement mandrel by means of a

Cross slide, which in turn is connected by means of two opposite cross members with linear drives, can be moved axially. If the cross slide is moved axially, thus, so to speak, the inner Displacement pin moved in the axial extrusion direction. The optionally in operative connection with the inner displacement mandrel

Wedge-shaped elements deflect this axial movement, preferably by means of a second dovetail guide, into a radial movement arranged perpendicular to the axial movement. This leads to a spreading of the wedge-shaped elements and this wedge movement of the forming gap between the wedge-shaped element and die is reduced and consequently reduces the wall thickness of the hollow profile.

For a subsequent increase in wall thickness, the linear drives are moved back to the starting position, ie against the

Extrusion direction. By this movement, the cross member including the cross slide are retracted. As a result of this rearward movement of the inner displacement mandrel, this displacement is transmitted via the optional second dovetail guide to the wedge-shaped element (s) so that they move radially in the direction of the inner displacement mandrel. As a result, the shaping gap is increased again.

Further features and advantages of the invention will become apparent from the

In the following description, embodiments of the invention will be described by way of example with reference to schematic drawings, without thereby limiting the invention.

In this case shows:

Fig. 1: A perspective view of an embodiment of a bridge tool according to the invention;

Fig. 2 is a schematic plan view of the bridge tool according to

FIG. 1;

Fig. 3 is a schematic side sectional view of the bridge tool according to Figure 1; and

4 A perspective view of an embodiment of a mandrel element of a bridge tool according to the invention. FIG. 1 shows a perspective view of an embodiment of a bridge tool according to the invention. This comprises a transducer 1, on whose outer sides two linear drives 2 are arranged in the form of hydraulic cylinders. Each of the linear drives 2 is connected to a cross member 3, which ends at two opposite sides of a cross slide 4 and are positively connected thereto. The gap between a mandrel element 5 and the die 6 defines the wall thickness of the hollow profiles to be produced. The die 6 is attached to a pressure plate 7. The mandrel element 5 additionally comprises wedge-shaped elements 8 and an inner displacement element 9.

In Figure 2, the bridge tool according to Figure 1 in a plan view in

Section shown. Together with the side view in section in Figure 3, the operating principle of a bridge tool according to the invention is clearly visible. The inner displacement mandrel 9 is in a first

Recess 10 is arranged, which extends in the axial direction and to which two second recesses 11 for the cross slide. 4

connect. A movement of the linear drives 2 lead to a

Displacement of the cross member 3 and the cross slide 4 and thus of the inner displacement pin 9 in the radial direction. This axial

Displacement of the inner displacement mandrel 9 leads to a radial movement of the wedge-shaped elements 9 and thus to a change in the gap between the mandrel element 5 and the die 6. By this change in the gap, the cross section of the hollow profile to be produced changes.

In addition, two first dovetail guide 13 for the wedge-shaped elements 8 and two second dovetail guides 14 are shown in FIG. These first dovetail guides 13 ensure that the wedge-shaped elements 8 can move only in the radial direction, while the second dovetail guides 14 allow, in addition to radially outwardly acting pressure forces with a displacement of the inner displacement pin 9 and tensile forces of the inner sliding mandrel 9 and the wedge-shaped elements 8 can be transmitted. The in the preceding description, the claims and the

Drawings disclosed features of the invention may be essential both individually and in any combination for the realization of the invention in its various embodiments.

Claims

claims

1 . Bridge tool for a device for direct extrusion of

Hollow profiles with variable wall thickness, comprising a die and at least one mandrel element with a die opening facing the first end and an opposite second end, wherein the outer profile contour of a hollow profile by the geometry of the die opening and the inner

Cross section of a hollow profile is defined by at least one mandrel element, characterized in that

the at least one mandrel element has at least one recess in which an inner displacement mandrel is movably mounted in the axial direction, the inner displacement mandrel being different in its first end region facing the first end of the mandrel element

Has cross sections.

2. Bridge tool according to claim 1, characterized in that

the mandrel member comprises at least a second axial recess extending in the axial direction along the first end portion of the inner

Displacement mandrel opposite the second end portion of the inner displacement mandrel extends, wherein one, in particular almost perpendicular to the at least one mandrel element arranged transverse slide is included, which is at least partially inserted into the at least one second recess, and wherein the cross slide is in operative connection with the inner displacement mandrel, in particular is firmly connected to the inner displacement mandrel.

3. bridge tool according to claim 2, characterized in that

the cross slide directly or by means of at least one cross member with at least one drive device can be brought into active connection or is stationary, wherein the drive device is designed and set up, the

Cross slide and the inner displacement mandrel to move in the axial direction.

4. bridge tool according to claim 3, characterized in that

a first cross member is disposed at a first radial end of the cross slide and a second cross member is disposed at a second, opposite the first radial end, radial end of the cross slide, wherein the first cross member with a first drive device and / or the second cross member with a second Drive device in

Active compound can be brought or stands.

5. bridge tool according to one of claims 2 to 4, characterized

marked that

the first and / or the second drive device is designed in the form of a linear drive, in particular in the form of a hydraulic cylinder.

6. bridge tool according to one of the preceding claims, characterized

marked that

the inner displacement mandrel in the region of its first end in axial

Direction in sections a trapezoidal or triangular

Cross section has.

7. bridge tool according to claim 6, characterized in that

the inner displacement mandrel is operatively connected to at least one wedge-shaped element at or in the region of its first end, or in particular the further pitch angle β of the side of the at least one wedge-shaped element facing the inner displacement mandrel is smaller or equal the pitch angle ß, so that an axial displacement of the inner displacement mandrel is converted into a corresponding radial displacement of the at least one wedge-shaped element.

8. bridge tool according to claim 7, characterized in that

at least one second wedge-shaped element is arranged mirror-symmetrically to the first wedge-shaped element on the opposite side of the first wedge-shaped element of the inner displacement mandrel.

9. bridge tool according to claim 7 or claim 8, characterized

marked that

the at least one wedge-shaped element by means of a first

Dovetail guide is connected to the mandrel element, wherein the at least one dovetail guide allows movement of the at least one wedge-shaped element exclusively in the radial direction, and wherein the dovetail guide in particular of the

Mandrel element and the at least one wedge-shaped element is formed.

10. bridge tool according to one of claims 7 to 9, characterized

marked that

the inner displacement mandrel and the at least one wedge-shaped element by means of a second formed in the axial direction

Dovetail guide are connected so that an axial movement of the inner displacement mandrel is converted into a radial movement of the at least one wedge-shaped element.

1 1. Bridge tool according to one of the preceding claims, characterized

marked that

the first recess of the mandrel element and the at least one inner displacement mandrel form a third dovetail guide in the axial direction, so that the inner displacement mandrel and the mandrel element are connected to one another by means of a dovetail guide.

12. An apparatus for direct extrusion comprising a bridge tool according to one of the preceding claims.

13. Use of a bridge tool according to one of claims 1 to 1 1 for the manufacture of one or more extruded profiles with in

Pressing direction variable cross-sections in a device for direct extrusion.