Method for producing bent profiles from sheet metal, in particular lightweight profiles, on a bending machine, and a tool arrangement on a bending machine for producing bent profiles

Abstract

Method for producing bent profiles (10) from sheet metal (2), in particular lightweight profiles, on a bending machine (19), comprising a profiling station (4) and a bending station (21) following in the through-direction (13) of the profile (10) to be produced, wherein Tensile and / or compressive stresses and / or torsional stresses are applied to the sheet metal (2, 5) to be profiled and bent between a first clamping unit (3) arranged in front of the first profiling station and the bending station (21) before the at least one profiling station (4). The sheet metal (2) to be profiled is first pre- or final-profiled in the profiling station (4) by profiling tools under the influence of the introduced tensile and / or compressive stresses and / or torsional stresses, and then the bending tools (9) of the bending station (21) bend the profiled sheet metal (5). characterized by the fact that the first clamping unit (3) travels along the longitudinal axis (13) of the sheet to be profiled (2) during bending and maintains the applied tensile and / or compressive stresses and / or torsional stresses during profiling and bending of the sheet to be profiled (2).

Description

[0001] The invention relates to a method for producing bent profiles from sheet metal, in particular lightweight profiles, according to the preamble of claim 1, and to a tool arrangement on a bending machine for producing bent profiles according to the preamble of claim 11.

[0002] Thin-walled sheet metal profiles are widely used in industry. These thin-walled profiles are often processed not only in a straight but also in a bent state, which requires additional profile bending processes. Typically, the profile shape is first produced, for example, in a roll bending process on a profiling machine, and then the profiled sheet is transferred into the bent configuration on a bending machine.

[0003] Depending on the application and batch size of such components, the manufacturing process varies. This process chain typically involves machining using different machines, methods, and often different companies. This makes the production of such bent profiles complex and expensive.

[0004] DE 102 25 036 A1 discloses a combination of profiling and bending of a thin-walled sheet metal profile, in which the process for producing bar profiles and the process for bending the produced bar profile are combined in a single, specially designed roll forming and bending machine. Similar solutions with specially developed forming machines are disclosed in DE 10 2005 000 893 A1 and DE 10 2011 117 769 A1.

[0005] Such approaches to sequentially performing profiling and bending operations on a single production unit have the disadvantage that they require elaborate and complex, purpose-built machines on which only such parts must typically be manufactured in relatively high quantities to make the investment worthwhile. Furthermore, the typically sequential execution of profiling and bending necessitates two separate forming processes, which can be problematic from a materials engineering perspective, for example, due to the impact on the properties of the sheet metal.

[0006] DE 10 2011 117 769 A1 discloses a machine configuration for roll forming bending on a bending machine with a profiling station and a bending station following it in the direction of travel of the profile to be produced. A clamping unit is arranged upstream of the profiling station, which, in conjunction with a clamping device at the bending station, applies tension to the sheet metal to be profiled. However, these clamping units are fixed in position, which means that the tension state cannot be optimally adjusted, especially for bending.

[0007] The object of the present invention is therefore to enable combined profiling and bending of thin-walled sheet metal profiles, which can be carried out on conventional bending machines and with which the disadvantages of previously known combination methods are avoided.

[0008] The solution to the problem according to the invention is achieved with respect to the method by the characterizing features of claim 1 and with respect to the tool arrangement by the characterizing features of claim 11 in conjunction with the features of the respective preamble. Further advantageous embodiments of the invention are set forth in the dependent claims.

[0009] The invention relates to a method for producing bent profiles from sheet metal, in particular lightweight profiles, on a bending machine, comprising a profiling station and a bending station following in the direction of travel of the profile to be produced. Such a generic method is further developed in an inventive manner by applying tensile and / or compressive stresses and / or torsional stresses to the sheet metal to be profiled and bent between a clamping unit and the bending station upstream of the at least one profiling station. Under the influence of the applied tensile and / or compressive stresses and / or torsional stresses, the sheet metal to be profiled is first pre- or final-profiled in the profiling station by profiling tools, and subsequently the bending tools of the bending station bend the profiled sheet metal.A key characteristic of the inventive method is the application of tensile and / or compressive stresses and / or torsional stresses by the clamping unit to the entire area in which the profiling and bending of the profile to be produced takes place, and the immediate sequence of profiling and bending in a single process pass. Furthermore, all process steps can be carried out, for example, on a conventional CNC bending machine, thus eliminating the need to purchase expensive special-purpose machines and increasing the utilization of such conventional CNC bending machines. The combined process of profiling and bending is further enhanced by mutual interactions. In the combined profiling and bending process, the material of the profile to be produced is only brought into the plastic state once and is simultaneously deformed in both cross-section and profile bending geometry.This further reduces the required manufacturing stages, increases the formability and manufacturing accuracy in the profile bending geometry and in the cross-sectional geometry.

[0010] The invention comprises a novel forming tool and process concept consisting of an integrated combination of profile manufacturing and profile bending processes for producing bent, thin-walled profiles. The entire process chain of profiling and bending can be integrated into a single tool system. The interactions between the profile manufacturing and profile bending processes are advantageously utilized in this profiling and bending process to minimize the process chain, enhance process robustness, and expand the process limits. A further advantage is that the novel tool and process technology is designed for adaptation to modern CNC bending machines. This method allows for excellent utilization of the potential of modern CNC profile bending machines. Furthermore, complex bent profile components can be produced in a single process pass.Adjustable process parameters make it possible to achieve complex cross-sectional shapes with good component accuracy and a small number of forming stages. This avoids expensive tooling stages by combining profiling and bending.

[0011] It is particularly advantageous if the profile to be produced is made from flat sheet metal strip, preferably coiled, or from flat sheet metal sections or even pre-profiled sheets. This allows for both the continuous production of longer profiles and virtually unlimited profile lengths, as well as the individual production of defined profile sections from prefabricated individual sheet metal sections.

[0012] It is of particular importance that the clamping unit moves along the longitudinal axis of the sheet metal being profiled during bending and maintains the applied tensile and / or compressive stresses and / or torsional stresses during the profiling and bending process. This ensures that, regardless of the profiling and bending state of the profile being produced, the materially advantageous application of tensile and / or compressive stresses and / or torsional stresses to the forming area within both the profiling and bending phases remains constant or is adjusted accordingly. This results in consistent and improved forming conditions compared to unpreloaded profiling or bending.In particular, the material of the sheet metal section to be profiled is only brought into the plastic range once by the applied tensile and / or compressive stresses and / or torsional stresses, and is then formed in this plastic state with respect to both its cross-section and bending geometry. This reduces the necessary forming stresses that must be applied in the profiling or bending station and improves the forming process.

[0013] In a further embodiment, it is also possible for the pre- or final profiling of the profile to be produced in the profiling station to be carried out by a roll forming unit and / or by a tool element for slide bending. Depending on the type of profiling and the profile cross-sections to be produced, roll forming, slide bending, or a multi-stage combination of such profiling processes may be advantageous. In a further embodiment, the pre- or final profiling of the profile to be produced in the profiling station can be carried out in a single stage or in multiple stages. With multi-stage profiling, for example, lower degrees of deformation can be achieved in the individual stages, which allows the material to be formed more gently, especially in the case of complex profile shapes or materials that are difficult to form. Furthermore, the application of different profiling processes sequentially in the individual stages is also possible.conceivable for different areas of the profile cross-section.

[0014] Furthermore, it is advantageous if the profiled sheet metal is bent in the bending station and its cross-sectional shape is simultaneously finalized. This makes it possible to subsequently compensate for inaccuracies in the profile cross-section resulting from the processing in the profiling station. For example, in the bending stage, the profiled sheet metal is pressed against the working elements of the bending station, particularly a bending roller, by means of at least one counter-support. This counter-support can then be used to calibrate the cross-section of the bent profile and eliminate any remaining inaccuracies in the cross-sectional shape produced in the profiling station. Such a counter-support then only needs to perform minor deformations of the profile cross-section, such as precisely defining profile corners or similar.

[0015] Furthermore, it is conceivable that a clamping device interacts with the clamping unit at the bending station, applying tensile and / or compressive and / or torsional stresses to the profile being formed. The clamping unit located upstream of the profiling station and a similar clamping device located at the bending station subject the sheet metal between them to tension or torsion as it passes through the profiling and bending stations, thus applying a uniform preload to this section of the sheet metal, which facilitates the forming of the sheet metal in the profiling and bending stations.In a further embodiment, the clamping device can rotate with the bending device, in particular the bending roller, during the bending of the profiled sheet metal, whereby the stress state of the sheet metal between the clamping device and the clamping unit can be kept constant regardless of the bending state of the profile to be produced, if the clamping unit is moved accordingly.

[0016] Furthermore, continuous profiling and bending of the profile to be produced is conceivable by profiling and bending a longer sheet of metal section by section. In this process, the desired deformation is achieved section by section by profiling and bending a longer piece of the starting material, and then repeated on a subsequent section of the sheet. This also makes it possible for the profile to achieve a bending angle of more than 360° by bending it helically. With a flat bend of the profile, a maximum bending angle of 360° would be possible, as the profile would then collide with subsequent sections of the sheet. However, if the profile is bent upwards out of the bending plane, for example in a helical fashion, multiple turns or similar configurations are possible, such as for heat exchangers or similar applications.Components are needed to be manufactured.

[0017] Furthermore, it is conceivable that the bending station can be controlled in such a way that the profile to be produced has a changing bending radius or sections with different bending radii after bending. For this purpose, the bending tools of the bending station can be controlled so that the resulting bending radius of the profile to be produced changes continuously or differently in sections. This allows for the easy production of particularly complex bending geometries.

[0018] Further improvements in the forming of the sheet metal profile can be achieved by heating the profile before the profiling station and / or the bending station. This thermally influences the forming limit of the sheet metal material, allowing the forming process to be carried out with lower forces. It is also conceivable to utilize heating to selectively control the microstructure of the profile, for example, by following the pre-forming heating with a corresponding post-forming cooling phase that induces a desired microstructure change.

[0019] The invention further relates to a tool arrangement on a bending machine for producing bent profiles from sheet metal, in particular lightweight profiles, comprising a profiling station and a bending station following the profile to be produced in the direction of travel. Such a tool arrangement is further developed by arranging a clamping unit upstream of the profiling station, which, in conjunction with a clamping device at the bending station, applies tensile and / or compressive stresses and / or torsional stresses to the sheet metal to be profiled up to the end of the bending station. The profiling station pre- or final-profiles the sheet metal to be profiled, wherein the profiling station is arranged directly upstream of the bending station. In the bending station, the bending tools bend the sheet metal to be profiled and, if necessary, complete the cross-sectional shape of the profiled component.The advantages and properties of applying tensile and / or compressive stresses and / or torsional stresses in the area of ​​the profiling station and the bending station have already been explained in relation to the method described above, to which full reference is made regarding the tool arrangement.

[0020] It is particularly advantageous if the clamping unit is designed to be movable parallel to the longitudinal axis of the profiled sheet metal and laterally to it. This allows for the generation of a wide variety of tensions by appropriately displacing the clamping unit relative to the flow direction of the sheet metal through the profiling and bending stations, thereby favorably influencing the forming of the sheet metal in both stations.

[0021] Furthermore, it is advantageous if a clamping device, particularly a jaw-like one, is arranged at the bending station, preferably at the exit area of ​​the bending station. This clamping device interacts with the clamping unit and pre-tensions the sheet metal to be profiled and bent, together with the clamping unit. By clamping the sheet metal in the jaw-like clamping device and simultaneously in the clamping unit, the sheet metal to be profiled and bent can be brought into a constant, imposed state of stress. This stress is maintained throughout the entire processing in the profiling and bending stations and is superimposed on the respective stress resulting from the action of the profiling and bending tools. For this purpose, the jaw-like clamping device can be arranged so that it rotates synchronously with the bending device when the, for example, roller-like bending tools are pivoted or when the profile to be produced is bent relative to these bending tools.The type and magnitude of the tension depend on the respective interaction of the clamping unit and the clamping device, i.e., when applying tensile stresses, on the degree of force exerted by the clamping unit on the sheet metal relative to the clamping device which is stationary relative to the bending roller.

[0022] It is also conceivable that the profiling tools of the profiling station are adjustable laterally to the direction in which the sheet metal is being profiled, thus enabling the production of profiles with variable wall thickness and / or variable profile shape. This allows the profiling tools of the profiling station to be influenced as the sheet metal passes through, thereby changing the profile of the sheet and thus influencing both the wall thickness and the profile shape. This makes it possible, in particular, to produce complex profiles with varying longitudinal or graded profiles.

[0023] Furthermore, the bending station can include bending devices for rotary draw bending and / or three-roll bending, which can be advantageous for the forming process depending on the type of profile bend. Combinations of such bending devices are also conceivable.

[0024] In addition to the production of open, thin-walled profiles, it is also conceivable to produce closed profiles or profiles with complex cross-sections using the tool arrangement according to the invention. For this purpose, mandrels can be inserted into the profile to be produced in the area of ​​the profiling station and / or bending station to support complex profiles and hollow profiles, in particular tubes. The forming of the profile and its support during the forming process are improved.

[0025] It is also conceivable to arrange a trimming station at the outlet of the bending station, which allows trimming, in particular cutting the manufactured profile to the finished dimensions.

[0026] For more complex, spatially curved profiles, it is conceivable to provide a number of such tool arrangements for multi-level bending of the profiles to be produced on multi-level bending machines, with each of the tool arrangements being responsible for one of the bending directions.

[0027] In terms of forming technology, it is also advantageous to arrange heating devices, particularly inductive heating devices with preferably cooled rollers, upstream of the profiling station and / or the bending station, with which the profile to be formed can be additionally heated. This heating can significantly improve the forming behavior, especially of materials that are difficult to form, or even make forming possible in the first place.

[0028] A particularly preferred embodiment of the tool arrangement according to the invention is shown in the drawing.

[0029] They show: Fig. 1 - a schematic representation of the basic structure of the tool arrangement according to the invention on a commercially available CNC bending machine, Fig. 2 - first step of a sequence of profiling and bending in the tool arrangement according to the inventive method with profiling of the profile to be produced, Fig. 3 - second step of a sequence of profiling and bending in the tool arrangement according to the inventive method with bending of the profile to be produced, Fig. 4 - Profiling and bending of a further section of the sheet metal in the tool arrangement according to the inventive method after resetting the bending roller, Fig. 5 - Illustration of the forming stages in the production of the profile to be manufactured according to the sequence in the Fig. 2, Fig. 3 to Fig. 4, Fig. 6 - Calibration of the profile cross-section in the bending stage, Fig. 7 - a schematic representation of a modification of the tool arrangement according to the invention Fig. 1 for bending profiles of longitudinally welded pipes, Fig. 8 - Schematic representation of the bending profile of a longitudinally welded pipe according to Fig. 7 with internal spine counterweight.

[0030] In the Fig. Figure 1 shows a schematic representation of the basic structure of the tool arrangement 18 according to the invention on a commercially available CNC bending machine 19, in which a sheet metal unwound from a coil 1 is profiled into a sheet metal cross-section 5 in a profiling station 4 and subsequently bent in a bending station 21 with a bending roller 9. The bending station 21 has a bending roller 9 for this purpose, which can be pivoted about a rotary axis 16. The bending station 21 is a standard component of a conventional bending machine with a CNC control for performing the individual movements and requires only the modifications listed below to enable the combination of profiling and bending.The bending roller 9 typically has a profile shape on its outer circumference that corresponds to the finished profile shape of the profile 10 to be produced and into which the sheet metal 5, previously profiled in the profiling station 4, can be inserted. Adjacent to the bending roller 9, a counter-holder 6 is arranged. This counter-holder, together with the bending roller 9, forms a channel shaped according to the cross-section of the profile 10 to be produced, allowing the profiled sheet metal 5 to pass through. Together with the profile shape of the bending roller 9, the counter-holder 6 can be used to recalibrate and rework the profiling of the profiled sheet metal 5. The outer profile shape of the bending roller 9 and the profile shape of the counter-holder 6 thus form a kind of calibration channel through which the profiled sheet metal 5 is drawn during bending by the bending roller 9.A wrinkle smoother 11, which is known per se, can also be arranged in the area of ​​the bending roller 9 to further prevent wrinkling of the profiled sheet metal 5.

[0031] Profiling station 4 can comprise either a roll forming unit or a tool element for sliding bending, whose profiling tools are arranged either fixedly or adjustable, thereby allowing the resulting profile cross-sectional shape to be varied along its length. Such profiling tools are generally known.

[0032] A significant advantage of the tool arrangement 18 according to the invention is that a preload can be applied to the sheet metal 2 to be profiled, thereby simplifying the forming process in both the profiling station 4 and the bending station 21. For this purpose, a clamping unit 3 is slidably arranged on a guide bed 15 of the bending machine 19 upstream of the profiling station 4. This clamping unit can grip the sheet metal 2 unwound from the coil 1 and clamp it with clamping devices (not shown in detail). The sheet metal 2 is clamped and positioned via the clamping unit 3. The clamping unit 3 can be moved synchronously with the feed of the unwound sheet metal 2 in the feed direction 13, so that the clamping unit 3 follows the feed of the sheet metal 2 unwound from the coil 1 and moves along the longitudinal axis of the profile during bending, thus maintaining the superposition of the tension.A torsion unit 22 can also be arranged on the clamping unit 3, with which torsional stresses can be introduced into the developed sheet 2 by rotating the torsion unit 22 approximately about the feed direction 13.

[0033] The clamping unit 3 interacts with a clamping device 7 to generate the tension. The clamping device 7 is fixed to the bending roller 9 and pivots along with the bending roller 9 about the pivot axis 16. The clamping device 7 is jaw-shaped and can be moved towards and away from the bending roller 9 on a guide 20. As the clamping device 7 moves towards the bending roller 9, an end section of the bent profile 10 located between the bending roller 9 and the clamping device 7 can be clamped to the bending roller 9. For this purpose, the clamping device 7 can have a profile similar to that of the counter-support 6. However, it is also conceivable to design the clamping device 7 without a profile, e.g., flat or rounded.

[0034] Between clamping unit 3 and clamping device 7, the sheet metal passing through profiling station 4 and bending station 21 can now be subjected to tensile and / or compressive stresses and / or torsional stresses. To generate tensile stresses in the sheet metal 2, the clamping unit 3 can be moved by a drive unit 14 approximately opposite to the feed direction 13 of the sheet metal 2 unwound from the coil 1, thereby pulling on the sheet metal 1, which is clamped to the bending roller 9 by the clamping device 7 in the area of ​​bending station 21. Compressive stresses can be introduced into the sheet metal 2 by the clamping unit 3 additionally pressing the sheet metal 2 towards the profiling station 4. Torsional stresses in the sheet metal 2 can be generated as described in the Fig. 1 not specified in more detail, are generated by rotating the clamping unit 3 relative to the feed direction of the sheet metal 2. These additional stresses introduced into the sheet metal 2 to be formed by the clamping unit 3 in conjunction with the clamping device 7 act on the sheet metal 2 to be profiled and bent along the entire length between clamping unit 3 and clamping device 7, and thus not only in the area of ​​the profiling station 4 but also in the area of ​​the bending station 21. These additional stresses introduced into the sheet metal 2 to be formed have a positive effect on the forming behavior of the sheet metal 2 in the profiling station 4 and in the bending station 21, thereby simplifying the respective forming processes.

[0035] First, the sheet metal 2 is prepared. For this purpose, either a sheet metal strip of a defined length is fed in (not shown) or a corresponding piece of sheet metal is unwound from a coil 1. The sheet metal 2 is clamped by the clamping unit 3 and unwound to the required length. The clamping unit 3 and the clamping device 7 then allow the tensile / compressive stresses as well as torsional stresses to be introduced into the forming process, as described. A profiling station 4 either pre-profiles or fully profiles the desired profile geometry of the profiled sheet metal 5. Pre-forming or final forming of the profiled sheet metal 5 can be carried out by an upstream roll forming unit (not shown) and / or by a tool element for slide bending.The profiling tools of the roll forming unit, designed as rolling rollers, can also be adjusted laterally, allowing the production of profiled sheets 5 with variable wall thicknesses or profile shapes. Multi-stage roll profiling or a combination with slide bending by connecting several profiling stations 4 in series is also conceivable. Tight radii and geometric deviations of the sheet 5 profiled in the profiling station 4 can then be recalibrated in the bending station 21 using the counter-holder. In the subsequent profile bending stage, two process steps take place simultaneously in the bending station 21. The pre-formed profiled sheet 5 is bent, and at the same time, the cross-sectional shape can be finalized in the bending tool, here the bending roller 9, during the profile bending process.This can be done in the bending station 21 both by means of rotary draw bending tools such as the bending roller 9 and by a three-roll bending process not shown.

[0036] In the Fig. 2, Fig. 3 to Fig. Figure 4 shows a sequence of profiling and bending of a flat sheet metal 2 in the tool arrangement 18 according to the inventive method, with profiling of the profile 10 to be produced in the profiling station 4 and bending in the bending station 21. Fig. Figure 2 shows the state of the flat sheet 2 after passing through the profiling station 4, where the sheet 2 is pre-profiled, for example, into a roof-like shape to form the profiled sheet 5. The end of this pre-profiled sheet 5 emerges in the Fig. 2 enters the area of ​​bending station 21 and is clamped by the clamping device 7 on the bending roller 9. In the Fig. In step 3, the bending roller 9, with the profiled sheet 5 clamped to it, rotated approximately 90° and bent the previously profiled, but straight, sheet 5 into an approximately semicircular shape to form the bent profile 10. During bending, the clamping device 7 rotated with the bending roller 9, so that the stress superposition between the clamping unit 3 and the clamping device 7 was maintained throughout the entire bending process. The bending roller 9 formed the inner contour of the bent profile 10. The bending roller 9 served as a support and shaping element during the forming of the profile 10. Through the combination with the stress superposition and the counter-support 6, the bent profile 10 could also be calibrated in the bending station 21.

[0037] In the Fig. Figure 4 shows the profiling and bending of another section of the flat sheet 2 after the bending roller 9 has returned to its starting position and a subsequent section of the flat sheet 2 has been profiled and now lies against the bending roller 9 as a profiled sheet 5 ready for bending. The previously, according to Fig. 3 The profiled and bent section of the profile 10 to be produced protrudes beyond the bending roller 9 and can be cut off, for example, by means of a trimming unit 8 with a knife or the like.

[0038] In the Fig. 3 and Fig. Heating devices 12 are schematically indicated in front of the profiling station 4 and the bending station 21, for example inductive or conductive heating devices 12, with which the flat sheet 2 in front of the profiling station 4 and / or the profiled sheet 5 in front of the bending station 21 can be heated in a targeted manner, thereby simplifying the profiling process or the bending process by reducing the forming stress and minimizing springback.

[0039] The process sequence of the method according to the invention can be summarized approximately as follows: 1. Moving the clamping device 7 towards and clamping the front part of the profiled sheet 5 between bending roller 9 and clamping device 7. 2. Opening the clamping unit 3 and positioning the clamping unit 3. 3. Clamping the rear part of the flat sheet 2 and applying the stress superposition by the clamping unit 3. 4. Forming process: In this process, the bending roller 9 is rotated by a predetermined amount and around the axis of rotation 16, while the clamping unit 3 moves along with it and maintains the tension. During the forming process, the central part of the flat sheet 2 is profiled in one or more stages in the profiling station 4, and the profiled sheet 5 is calibrated and bent in the bending station 21. 5. Opening the clamping device 7 and retracting the bending roller 9 to its starting position. Opening the clamping device 7 releases the superposition of stresses. 6. Repeat step 1: Close the clamping device 7 and clamp the front part of the profiled sheet 5 between the bending roller 9 and the clamping device 7. However, when the clamping device 7 is closed, the already bent part of the profile 10 is now cut off by the trimming unit 8. 7. Repeat from step 2.

[0040] The most important functions of the tool arrangement 18 and the method are: • Device for holding a coil 1 as strip material for a CNC bending machine • Clamping unit 3 for unfolding the flat sheet 2, positioning the flat sheet 2, as well as for tensile / compression and / or torsional superposition • Tool elements in profiling station 4 for forming the profile geometry by roll forming / slide drawing bending • Tool elements 9 in the bending station 21 for bending the profile geometry by rotary draw bending or three-roll shear bending • Providing the function for trimming 8 the manufactured profile within the tool arrangement 18 • Providing an integrated tooling solution comprising tool elements 4 and 21 to form a complete tool

[0041] Other possible variations of the procedure include: • The starting material for profiling / bending can be a sheet metal strip 2 from a coil 1, a sheet metal strip 2 of defined length, or an already profiled sheet metal strip 2. • The wall thickness of the profiled and bent sheet metal 10 can be either constant or variable. • Both open and closed cross-sections can be profiled and bent. • It is conceivable to profile and bend tubes as the starting material. For this purpose, for example, a sheet metal strip 2 is formed into a tube, welded, and then bent. For this, the tool arrangement 18 between the profiling station 4 and the bending station 21 is supplemented by a welding device. • It is conceivable to further reshape already profiled cross-sections (e.g., round tubes to oval tubes) and then bend them.

[0042] In the Fig. Figure 5 is a representation of the forming stages in the production of the profile 10 to be manufactured, according to the sequence in the Fig. 2, Fig. 3 to Fig. 4 can be seen, whereby the flat sheet metal (partial figure under 1.) is pre-profiled into an approximately roof-shaped cross-section (partial figure under 2.) and then bent (partial figure under 3.) and calibrated. Here, according to Fig. 6 The calibration of the profile cross-section in the bending stage serves to optimize the angles and especially the radii in the corners of the pre-profiled sheet 5.

[0043] The Fig. Figure 7 shows a schematic representation of a modification of the tool arrangement according to the invention. Fig. 1 for bending profiles of longitudinally welded tubes, in which a round, largely closed cross-section of the profiled sheet 25 is produced in the profiling station 4. The more detailed process of this profiling to the tube 25 is described in the Fig. 8, which shows a schematic representation of the bending profile of a longitudinally welded pipe 28 according to Fig. Figure 7 shows the internal mandrel support 26. In addition to profiling in the profiling station 4, the profiled tube 25 is shaped by the mandrel support 26 into an approximately round or elliptical shape so that the two edges of the developed sheet 2, possibly slightly spaced apart, lie next to each other and form a space 24 for a weld 27, which is produced by a welding device (only schematically indicated) with a welding electrode 23, thus producing a longitudinally welded tube 28. Part number list 1 Coil 2 unwound sheets to be formed 3 clamping unit 4 Profiling station 5 profiled sheet metal 6 Counterholds 7 jaw-like clamping device 8 trimming units 9 Bending roller 10 profiled and bent sheet metal 11 wrinkle smoothers 12 Heating device 13 Feed direction sheet metal 14 Adjustment direction clamping unit 15 guide bed 16 Rotary axis bending roller 17 Setting directions for profiling tools 18 Tool arrangement 19 Bending machine 20 Guide clamping device 21 Bending station 22 Rotary device 23 Welding electrode 24 Space for weld seam 25 profiled pipe 26 Spindle holder 27 weld seam 28 longitudinally welded pipe

Claims

Method for producing bent profiles (10) from sheet metal (2), in particular lightweight profiles, on a bending machine (19), comprising a profiling station (4) and a bending station (21) following in the through-direction (13) of the profile (10) to be produced, wherein, prior to the at least one profiling station (4), tensile and / or compressive stresses and / or torsional stresses are applied to the sheet metal (2, 5) to be profiled and bent between a first clamping unit (3) arranged prior to the first profiling station and the bending station (21), the sheet metal (2) to be profiled is first pre- or final-profiled in the profiling station (4) by profiling tools under the influence of the applied tensile and / or compressive stresses and / or torsional stresses, and subsequently the bending tools (9) of the bending station (21) bend the profiled sheet metal (5).characterized in that the first clamping unit (3) moves along the longitudinal axis (13) of the sheet (2) to be profiled during bending and maintains the introduced tensile and / or compressive stresses and / or torsional stresses during profiling and bending of the sheet (2) to be profiled. Method according to claim 1, characterized in that the material of the sheet (2) to be profiled is brought into the plastic range only once by the introduced tensile and / or compressive stresses and / or torsional stresses and is formed in this plastic state both with respect to the cross-section and with respect to the bending geometry. Method according to one of claims 1 or 2, characterized in that the pre- or final profiling of the profile (10) to be produced in the profiling station (4) is carried out by a roll profiling unit and / or by a tool element for sliding bending, wherein the pre- or final profiling of the profile (10) to be produced in the profiling station (4) is preferably carried out in a single stage or in multiple stages. Method according to one of the preceding claims, characterized in that the profiled sheet (5) is bent in the bending station (21) and at the same time the cross-sectional shape of the profiled sheet (5) is fully formed. Method according to claim 4, characterized in that the profiled sheet (5) is pressed against the working elements of the bending station (21), in particular a bending roller (9), by means of at least one counter support (6), wherein preferably the at least one counter support (6) is used to calibrate the cross-section of the bent profile (10). Method according to one of the preceding claims, characterized in that a clamping device (7) at the bending station (21) interacts with the clamping unit (3) and, together with the clamping unit (7), applies tensile and / or compressive stresses and / or torsional stresses to the sheet metal (2) to be formed, for this purpose the clamping device (7) rotates with the bending station (21), in particular the bending roller (9), especially during the execution of the bending of the profiled sheet metal (5). Method according to one of the preceding claims, characterized in that continuous profiling and bending of the profile (10) to be produced is carried out by profiling and bending a longer sheet material (2) section by section. Method according to claim 7, characterized in that the profile (10) to be produced achieves a bending angle of more than 360° by bending in a helical manner. Method according to one of the preceding claims, characterized in that the bending station (21) is controlled such that the profile (10) to be produced has a changing bending radius or sections with different bending radii after bending. Method according to one of the preceding claims, characterized in that the sheet (2, 5) of the profile (10) to be produced is heated before the profiling station (4) and / or before the bending station (21). Tool arrangement (18) on a bending machine (19) for producing bent profiles (10) from sheet metal (2), in particular lightweight profiles, on a bending machine (19), comprising a profiling station (4) and a bending station (21) following in the through-direction (13) of the profile (10) to be produced, characterized in that a first clamping unit (3) is arranged in front of the first profiling station (4), which is movably designed parallel to the longitudinal axis (13) of the profile (10) to be produced and moves along the longitudinal axis (13) of the sheet metal (2) to be profiled during bending such that, in conjunction with a clamping device (7) at the bending station (21), tensile and / or compressive stresses and / or torsional stresses are applied to the sheet metal (2) to be profiled up to the end of the bending station (21), the profiling station (4) pre- or final-profiling the sheet metal (2), wherein the profiling station (4) is located directly in front of the bending station (21) is arrangedand in the bending station (21) the bending tools (9) bend the sheet metal (5) to be profiled. Tool arrangement (18) according to claim 11, characterized in that the tool arrangement (18) is arranged on a conventional profile bending machine (19). Tool arrangement (18) according to one of claims 11 or 12, characterized in that the clamping unit (3) is designed to be movable parallel to the longitudinal axis (13) of the profile (10) to be produced and laterally thereto. Tool arrangement (18) according to one of claims 11 to 13, characterized in that a clamping device (7), in particular jaw-like, is arranged at the bending station (21), preferably at the exit area of ​​the bending station (21), which interacts with the clamping unit (3) and pre-tensions the profile (2, 5) to be formed together with the clamping unit (3), wherein the clamping device (7) is preferably arranged to be pivotable such that it rotates with the bending device (21), in particular the bending roller (9), during the execution of the bending of the profiled sheet (5). Tool arrangement (18) according to one of claims 11 to 14, characterized in that the profiling tools of the profiling station (4) are adjustable laterally to the direction of travel (13) of the profiled sheet (5), making it possible to produce profiles with variable wall thickness and / or variable profile profile. Tool arrangement (18) according to one of claims 11 to 15, characterized in that the bending station (21) has devices for rotary draw bending and / or for three-roll bending. Tool arrangement (18) according to one of claims 11 to 16, characterized in that mandrels can be inserted into the profile (10) to be produced in the area of ​​the profiling station (4) and / or bending station (21) to support complex profiles (10) and hollow profiles, in particular tubes. Tool arrangement (18) according to one of claims 11 to 17, characterized in that a trimming station (8) is arranged at the outlet of the bending station (21), which allows trimming, in particular cutting to length of the produced profile (10) to finished dimensions. Tool arrangement (18) according to one of claims 112 to 18, characterized in that a number of such tool arrangements (18) are provided for multi-level bending of the profiles (10) to be produced on multi-level bending machines (19). Tool arrangement (18) according to one of claims 11 to 19, characterized in that heating devices (12), in particular inductive heating devices (12) with preferably cooled rollers, are arranged in front of the profiling station (4) and / or in front of the bending station (21), with which the profile (2, 5) to be formed can be additionally heated.

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