DE102018131967A1 - Method for calibrating a curved hollow metal profile - Google Patents

Abstract

The invention relates to a method for producing a curved metallic hollow section (1) with the following method steps: a) providing a metallic hollow section (1) with two open end regions (2, 3), the hollow section (1) covering at least one over its entire longitudinal extent extending hollow chamber (4,5), b) inserting the hollow chamber profile (1) into a cavity (6) of an open pressing tool (7), c) inserting expandable inner tools (8, 9; 10, 11) into the at least one hollow chamber (4, 5) in the two end regions (2, 3) of the hollow chamber profile (1), at least one of the inner tools (8, 9; 10, 11) having a curved shaped section which extends along a longitudinal axis of the hollow chamber profile, d) Widening of the expandable internal tools (8, 9; 10, 11) arranged in the at least one hollow chamber (4, 5) of the hollow chamber profile (1), e) closing the pressing tool (7), f) returning the expansion of the internal work witness (8, 9; 10, 11) and leading them out of the at least one hollow chamber (4, 5) of the hollow chamber profile (1), g) opening the pressing tool (7), h) removing the now calibrated hollow chamber profile (1).

Description

The invention relates to a method for calibrating a curved hollow metal profile.

Profiles, in particular also hollow chamber profiles, made of aluminum or steel alloys are used as materials for a wide variety of applications in automotive and motor vehicle construction for many applications, such as, for example, engine carriers or front or rear longitudinal members of a motor vehicle. Since manufacturing tolerances of the hollow chamber profiles, in particular wall thicknesses, external dimensions and the like, from an extrusion process or extrusion process or, in the case of steel materials, also from the roll forming process are relatively large, so that coupling of the individual parts to one another or their joining is made more difficult. As a result, the large tolerances are reduced or compensated for today through time-consuming and cost-intensive machining of the joining areas, or more complex processes such as hydroforming which are disadvantageous with regard to the resulting component properties. The required oversize of the profiles also results in a higher total weight, since the wall thickness, higher than necessary for the operational strength, must be selected. This is questionable both economically and ecologically.

From the EP 1 534 443 B1 a method for producing structural components from an aluminum extruded profile in the field of motor vehicle construction is also known. In order to increase the accuracy with regard to the dimensions of the profile cross section, it is proposed there to forge the hot extruded profiles while maintaining the temperature in a hot forming process, in particular by means of internal high pressure forming, or to optimize them in the area of their open profile ends with regard to the accuracy of the profile cross section. This is also economically and ecologically questionable.

Furthermore, it is from the US 9,370,811 B2 known to calibrate an extruded tube for use in vehicle construction in such a way that the extruded tube is arranged in the cavity of a calibration tool, with clamps attached at the ends, which stretch the tube in the longitudinal direction by up to 4% and thereby carry out a corresponding calibration , in which twists and other deformations are to be reduced or eliminated. However, this means that the profile cross sections of the open end areas of the profiles cannot be adjusted, or only insufficiently, in terms of their accuracy of fit during subsequent joining.

All known methods for reducing the tolerances of such hollow chamber profiles, in particular curved hollow chamber profiles, are therefore not yet satisfactory, so that further improvements are necessary in order to reliably manufacture the outer surfaces or outer walls of the hollow chamber profile according to its future function with regard to its tolerances.

It is therefore an object of the invention to provide a method for producing a curved metallic hollow chamber profile and a corresponding hollow chamber profile in which the tolerances that occur during the production of the hollow chamber profile are further reduced or even eliminated, in particular over its entire outer surfaces or outer walls.

This object is achieved by a method for producing a curved metallic hollow chamber profile with all the features of patent claim 1. Advantageous embodiments of the invention can be found in the subclaims.

1. a) Bereitstellen eines metallischen Hohlkammerprofils mit zwei offenen Endbereichen, wobei das Hohlkammerprofil wenigstens eine sich über seine gesamte Längsausdehnung erstreckende Hohlkammeraufweist,
2. b) Einlegen des Hohlkammerprofils in eine Kavität eines offenen Presswerkzeugs,
3. c) Einführen von aufweitbaren Innenwerkzeugen in die wenigstens eine Hohlkammer in den beiden Endbereichen des Hohlkammerprofils, wobei wenigstens eines der Innenwerkzeuge einen gekrümmten Formabschnitt aufweist, der sich entlang einer Längsachse des Hohlkammerprofils erstreckt,
4. d) Aufweiten der in der wenigstens einen Hohlkammer des Hohlkammerprofils angeordneten aufweitbaren Innenwerkzeugen,
5. e) Schließen des Presswerkzeugs,
6. f) Zurückführen des Aufweitens der Innenwerkzeuge sowie deren Herausführen aus der wenigstens einen Hohlkammer des Hohlkammerprofils,
7. g) Öffnen des Presswerkzeugs,
8. h) Entnahme des nunmehr kalibrierten Hohlkammerprofils.

The method according to the invention for producing a curved metallic hollow chamber profile has the following method steps:

1. a) provision of a metallic hollow chamber profile with two open end regions, the hollow chamber profile having at least one hollow chamber which extends over its entire longitudinal extent,
2. b) inserting the hollow chamber profile into a cavity of an open pressing tool,
3. c) inserting expandable inner tools into the at least one hollow chamber in the two end regions of the hollow chamber profile, at least one of the inner tools having a curved shaped section which extends along a longitudinal axis of the hollow chamber profile,
4. d) expanding the expandable internal tools arranged in the at least one hollow chamber of the hollow chamber profile,
5. e) closing the pressing tool,
6. f) returning the expansion of the inner tools and leading them out of the at least one hollow chamber of the hollow chamber profile,
7. g) opening the pressing tool,
8. h) removal of the now calibrated hollow chamber profile.

The core idea of the invention is that a press tool is inserted into a cavity of a press tool Hollow chamber profiles by means of widened inner mandrels, which are supported essentially or partly on the inner walls of the hollow profile, possibly with plastic deformation of the hollow profile, and the pressing tool, which causes plastic deformation of the hollow profile during its closing, is calibrated with regard to its dimensions or dimensions of its outer surface or outer walls . The hollow profile or its external shape is calibrated or deformed to the desired dimensions during the method according to the invention, without its structural properties being impaired, in particular with regard to its resilience. In particular, the physical and application-related limits of the material or component, for example maximum ironing rate or maximum local wall thinning, should not be exceeded.

After inserting the hollow chamber profile into a cavity of an open pressing tool and inserting expandable inner tools into the at least one hollow chamber, the outer surfaces or outer walls of the curved hollow profile are deformed in such a way that the profile cross section of the two end regions is brought to a significantly narrower tolerance band, in which the distance the outer walls to each other and the angular position can be adjusted.

For this purpose, the pressing tool is closed and a force is applied to the hollow chamber profile from the outside, which causes a plastic deformation of the hollow chamber profile, while by means of the internal tools, by expanding them from the inside, a counterforce is applied into the hollow chamber profile or into the individual hollow chambers, which is preferably also plastic Deformation causes.

In the simplest case, the calibration can be carried out by mechanical processing in the form of inner and outer tools which can be displaced relative to one another. The pressing tool already described and having a cavity for inserting a hollow chamber profile is used as the external tool, while correspondingly expandable mandrels are used as internal tools, for example. After its actual manufacture, the hollow chamber profile to be calibrated is inserted into the corresponding pressing tool by extrusion, extrusion or roll forming and a corresponding length cut, so that this pressing tool completely, at least in sections, advantageously completely surrounds the hollow chamber profile. One or more internal tools in the form of expandable mandrels are then introduced into the hollow chamber profile at least in sections, so that at least the outer walls or outer surfaces of the hollow chamber profile are arranged between the two tools. Then the tools are moved towards one another by appropriate drives, in that the pressing tool is closed and the inner tools are expanded in the form of the mandrels. The corresponding wall area or outer walls of the hollow chamber profile are plastically deformed.

In this case, multi-part wedge-shaped inner tools are preferably used, for example in the form of expandable mandrels, which cause displacement of the at least one wall section of the end region of the hollow chamber profile to the outside by displacement in the longitudinal direction of the profile. This mechanical calibration is particularly preferably carried out in the pressing tool, which serves as an external tool and, in the closed state, defines the desired geometry in the outer region of the end regions of the hollow chamber profile after the calibration. The internal tools designed as mandrels are designed as precision-machined and expandable internal mandrels, so that the desired target geometry can be produced in the inner region of the at least one hollow chamber of the hollow chamber profile in the end regions of the hollow chamber profile.

As already mentioned, according to a first advantageous embodiment of the invention, the expandable internal tools are expanded by plastic deformation of the hollow chamber profile above the elastic limit of the material of the hollow chamber profile.

According to a preferred embodiment of the invention, the plastic deformation of the hollow chamber profile for calibration of the hollow chamber profile or its outer walls takes place essentially exclusively during the closing of the pressing tool.

According to an advantageous embodiment of the invention, the expandable mandrels used as internal tools are expanded via a wedge slide mechanism, in particular via a double wedge slide mechanism. For this purpose, a press drive is provided for the outer tool movement of the pressing tool and for the widening movement of the wedge mechanism of the inner tools.

It has proven to be advantageous that the respective inner tool has curved shaped areas, with straight wedge sections being formed opposite the shaped areas in such a way that a linear movement of an inner tool during expansion causes the Hollow chamber profile is curved or stretch bent. The hollow chamber profile experiences a curvature of 0.5 to 5 °, in particular 1 to 3 °.

So that the hollow profile can be calibrated over its entire outer surfaces, it has proven to be advantageous if the expandable inner tools are inserted into the at least one hollow chamber of the hollow chamber profile into a central region. In this respect, they then serve as a male part for the pressing tool designed with its cavity as a female part, so that the hollow profile can be reliably calibrated or deformed over its entire outer surfaces and thus also over its inner surfaces.

In order to achieve a narrow tolerance band, it is advantageous for the expandable internal tools arranged in the at least one hollow chamber to be expanded by an axial displacement in the corresponding hollow chambers of the hollow chamber profile with the pressing tool closed. Particularly when using a wedge mechanism, this is done by axially inserting the central or expansion mandrel, as a result of which the wedge mechanism expands upwards and downwards by approx. 2-3 mm in the form of an expansion. The depth of penetration of the central or expanding mandrel can vary between 1 mm and 10 mm depending on its shape.

This method according to the invention can be used particularly advantageously when hollow chamber profiles with a box-like profile cross section are used. Here, the outer surfaces to be calibrated can be calibrated particularly simply in the form of flat walls, since no complex calibration tools in the form of special geometries for the inner tools or mandrels and also the pressing tool have to be provided. The internal tools or mandrels then likewise have a simple box-shaped geometry in their cross section.

It is also advantageous if the inner tools already have a curvature corresponding to the desired curvature of the hollow profile. On the one hand, this ensures that a particularly good calibration result is achieved with regard to the hollow profile. On the other hand, such internal tools can be removed more easily from the curved hollow profile.

According to a particularly advantageous embodiment of the invention, additional structural elements such as embossments and beads or the like are introduced into the hollow comb profile with the aid of the pressing tool and the expandable inner tools during the closing of the pressing tool. No separate method steps are therefore necessary for attaching such structural elements. Advantageously, the attachment of such structural elements is only so deep that the internal tools can be removed from the hollow chambers of the hollow chamber profile again after their expansion has been returned.

According to a particularly advantageous embodiment of the invention, it is provided that the hollow chamber profile is compressed and stretched simultaneously or at different times during calibration. This also enables the longitudinal profile of the hollow chamber profile to be calibrated.

Furthermore, it has proven to be advantageous that the hollow chamber profile is provided as a straight extruded hollow chamber profile without previous further preforming steps.

Further objectives, advantages, features and possible uses of the present invention result from the following description of exemplary embodiments with reference to the drawings. All of the described and / or illustrated features, alone or in any meaningful combination, form the subject matter of the present invention, regardless of how they are summarized in the claims or their relationship.

• 1: ein Presswerkzeug zur Durchführung des erfindungsgemäßen Verfahrens vor dem Kalibrieren eines Hohlkammerprofils in einer perspektivischen Ansicht,
• 2 bis 6: verschieden Hohlkammerprofil, welche mit einem erfindungsgemäßen Verfahren hergestellt sind, in einer perspektivischen Ansicht.

Show it:

• 1 a perspective view of a pressing tool for carrying out the method according to the invention before calibrating a hollow chamber profile,
• 2nd to 6 : different hollow chamber profile, which are produced with a method according to the invention, in a perspective view.

A method step of a method according to the invention for calibrating a curved hollow metal profile 1 is in the 1 . In order to carry out such a calibration, the hollow chamber profile 1 into a cavity 6 of a pressing tool 7 inserted. After inserting the hollow chamber profile 1 into the cavity 6 of the pressing tool 7 are in the hollow chambers 4th and 5 in both end areas 2nd and 3rd of the hollow chamber profile 1 also slightly curved inner tools 8th and 9 respectively 10th and 11 introduced. Thereby, in the hollow chambers 4th and 5 in the end area 2nd the interior tools 8th and 9 and in the end area 3rd the interior tools 10th and 11 introduced. These interior tools 8th and 9 respectively 10th and 11 are designed in the present case as high-precision molded expandable mandrels, which inside the Hollow chambers 5 to 10th can be expanded. For this purpose, the inner tools or mandrels have wedge mechanisms with which the same can be expanded. All interior tools 8th , 9 , 10th and 11 are in a middle range 12 of the hollow profile 1 inserted. By expanding the inner tools 8th , 9 , 10th and 11 becomes the outer circumference of the inner tools 8th , 9 , 10th and 11 to the hollow chamber profile 1 or its inner contour adapted, while the inner contour of the hollow chambers 5 to 10th to the outer contour of the inner tools or mandrels 13 to 19th is adjusted. In the now expanded state, which in 3rd the internal tools are not shown 8th , 9 , 10th and 11 as a male part for the cavity 6 of the pressing tool, which is designed as a female part 7 .

After expanding the inner tools 8th , 9 , 10th and 11 becomes the pressing tool 7 closed, these outer walls of the hollow chamber profile 1 thus under counter pressure of the internal tools 8th , 9 , 10th and 11 be plastically deformed. Overall, the entire hollow profile is thereby calibrated with regard to its outer and also with regard to its inner contour.

In the 2nd to 6 are shifting curved hollow chamber profiles produced with the inventive method 1 shown in a perspective view.

All hollow chamber profiles 1 of the 2nd to 6 have a box-shaped profile cross section and are slightly curved over their longitudinal extent K provided which in the 2nd to 6 using a guide H between two corners of the hollow chamber profile 1 is made clear. The curvature K lies in the range of 0.5 to 5 °, measured as the angle between the auxiliary line H and a tangent T on the curved cavity wall at the intersection of the auxiliary line H with a corner of the hollow section 1 . The maximum curvature depends, among other things, on the number and internal dimensions of the hollow chambers, and on any local structural elements that may need to be formed. D side walls 14 and 15 the hollow chamber profiles 1 are at their ends over an upper wall 16 and a bottom wall 17th connected with each other.

Within the hollow chamber profiles 1 are in the embodiments of the 2nd to 4th two hollow chambers each 4th and 5 arranged which by an inner wall 11 are separated from each other, the inner wall 11 the top wall 16 with the bottom wall 17th connects. The hollow chambers 4th and 5 have an identical, box-shaped, essentially rectangular cross section in the present exemplary embodiments.

The hollow chamber profiles 1 of the 5 and 6 are, however, as single-chamber profiles with a hollow chamber 4th educated.

The hollow chamber profiles are along their longitudinal extent 1 with a mid-range 12 trained to each have a corresponding end region 2nd respectively 3rd of the respective hollow chamber profile 1 connects. During the calibration of the hollow chamber profile, the respective internal tools are expanded into this central area before they are expanded 12 pushed in, so that they serve as a male part for the cavity of a pressing tool, which is designed as a female part.

Regarding a median plane that is parallel to the top wall 16 and down the wall 17th the hollow chamber profiles 1 runs, these are hollow chamber profiles 1 with the exception of any structural elements that may be incorporated, mirror-symmetrical. In their end areas 2nd and 3rd the hollow chamber profiles show near their openings 1 if necessary, joining areas with which they can be joined to corresponding components in a component group in which they are to be used.

The hollow chamber profiles 1 are produced using an extrusion process or roll forming, depending on the starting material. Extrusion is ideal for the production of hollow sections made of aluminum or aluminum alloys, while roll forming is more suitable for hollow sections made of different steels. All these manufacturing processes for the hollow chamber profiles have in common that the manufacturing tolerances of the profiles are relatively large, especially in their end regions, so that the subsequent joining in the component groups in which they are to be used is made more difficult. Therefore, a hollow chamber profile 1 , as is the case in the 2nd to 6 is still calibrated so that it can be arranged in these component groups in a simple manner and joined with other components without internal stresses in the hollow chamber profile 1 or other components of the component group occur.

While the hollow profile 1 of the 2nd has flat outer walls are in the upper walls of the hollow profiles 1 of the 3rd to 6 move structural elements arranged as during the calibration of the hollow profiles 1 was introduced without the need for a separate manufacturing step. All that is required is the inner tools 8th , 9 , 10th and 11 as well as the cavity 6 of the pressing tool 7 of the 1 be provided with appropriate contour surfaces.

The curved hollow profile of the 3rd has structural elements in the form of embossed surfaces or beads 18th at the transitions of the top wall 16 to the side walls 14 and 15 on the inside of the hollow profile 1 extend.

In addition to beads 18th has the curved hollow profile of the 4th on the top wall 16 on two more holes 19th on, which also during calibration in the hollow profile 1 were introduced.

The hollow profile designed as a single-chamber hollow profile 1 of the 5 points to the transitions of the upper wall 16 to the side walls 14 and 15 inserted beads 18th on. However, is on the top wall 16 additionally an embossing surface facing outwards 20th brought in. This can also have been introduced during the calibration, but then the plastic deformation in this case was generated by a corresponding contour of internal tools, which is the upper wall 16 has displaced into a cavity of the cavity of the pressing tool.

The hollow profile designed as a single-chamber hollow profile 1 of the 6 points to the transitions of the upper wall 16 to the side walls 14 and 15 inserted beads 18th on. However, is on the top wall 16 additionally a hole 21st with outward-facing collar 22 brought in. This edge collar can also have been introduced during the calibration, but then the plastic deformation in this case was generated by a corresponding contour of internal tools, which is the upper wall 16 has displaced into a cavity of the cavity of the pressing tool.

Reference symbol list

1

Hollow chamber profile

2nd

End area

3rd

End area

4th

Hollow chamber

5

Hollow chamber

6

cavity

7

Press tool

8th

Internal tool, mandrel

9

Internal tool, mandrel

10th

Internal tool, mandrel

11

Internal tool, mandrel

12

Middle range

13

Interior wall

14

Side wall

15

Side wall

16

top wall

17th

bottom wall

18th

Surround

19th

hole

20th

Stamping surface

21st

hole

22

Edge collar

K

curvature

H

Auxiliary line

QUOTES INCLUDE IN THE DESCRIPTION

This list of documents listed by the applicant has been generated automatically and is only included for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent literature cited

• EP 1534443 B1 [0003]
• US 9370811 B2 [0004]

Claims (12)

Method for producing a curved metallic hollow chamber profile (1) with the following method steps: a) providing a metallic hollow chamber profile (1) with two open end regions (2, 3), the hollow chamber profile (1) having at least one hollow chamber (4, 5) extending over its entire longitudinal extent, b) inserting the hollow chamber profile (1) into a cavity (6) of an open pressing tool (7), c) inserting expandable inner tools (8, 9; 10, 11) into the at least one hollow chamber (4, 5) in the two end regions (2, 3) of the hollow chamber profile (1), at least one of the inner tools (8, 9; 10, 11) has a curved shaped section which extends along a longitudinal axis of the hollow chamber profile, d) expanding the expandable internal tools (8, 9; 10, 11) arranged in the at least one hollow chamber (4, 5) of the hollow chamber profile (1), e) closing the pressing tool (7), f) returning the expansion of the inner tools (8, 9; 10, 11) and leading them out of the at least one hollow chamber (4, 5) of the hollow chamber profile (1), g) opening the pressing tool (7), h) removal of the now calibrated hollow chamber profile (1). Procedure according to Claim 1 , characterized in that the expandable inner tools (8, 9; 10, 11) are expanded above the elastic limit of the material of the hollow chamber profile (1). Procedure according to Claim 1 or 2nd , characterized in that the closing of the pressing tool (7) causes a plastic deformation of the hollow profile (1), in particular stretch bending along a longitudinal axis of the profile. Method according to one of the preceding claims, characterized in that mandrels are used as inner tools (8, 9; 10, 11) which can preferably be expanded by means of a wedge-slide mechanism, in particular by means of a double wedge-slide mechanism. Method according to one of the preceding claims, characterized in that the at least one of the inner tools (8, 9, 10, 11) has curved shaped areas, opposite to the shaped areas straight wedge sections being formed such that a linear movement of an inner tool (8, 9, 10, 11) when expanding the hollow chamber profile (1) is curved or stretched. Method according to one of the preceding claims, characterized in that the inner tools (8, 9; 10, 11) are inserted into the at least one hollow chamber (4, 5) of the hollow chamber profile (1) into a central region (12). Method according to one of the preceding claims, characterized in that the expansion of the expandable internal tools (8, 9; 10, 11) arranged in the at least one hollow chamber (5, 6, 7, 8, 9, 10) of the hollow chamber profile (1) an axial displacement of a part of the respective inner tool (8, 9; 10, 11) relative to the other parts of the respective inner tool (8, 9; 10, 11) takes place in the at least one hollow chamber (4, 5) with the pressing tool (7) closed . Method according to one of the preceding claims, characterized in that a hollow chamber profile (1) with a box-like profile cross section is used. Method according to one of the preceding claims, characterized in that with the help of the pressing tool (7) and the expandable inner tools (8, 9; 10, 11) during the closing of the pressing tool (7) further structural elements such as embossments and beads or the like into the hollow comb profile (1) can be introduced Method according to one of the preceding claims, characterized in that the hollow chamber profile (1) is compressed and stretched simultaneously or at different times during calibration. Method according to one of the preceding claims, characterized in that the hollow chamber profile (1) is extruded in step a) and is provided without preforming steps. Curved hollow chamber profile (1) produced by a method according to one of the preceding claims, with a curvature (K) between 0.5 and 5 °, in particular between 1 and 3 °.

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