EP2875877A1 - Method for producing a profile having varying a cross-section - Google Patents

Abstract

The present invention relates to a method for producing an elongate profile (1) having a longitudinally varying cross-section. In the method, an elongated metal strip (2), which has two strip edges (3), is profiled in a first profiling process to form a semi-finished profile (10). Subsequently, the semi-finished profile (10) is partially embossed in a second profiling process such that at least two sections (4, 5) are offset from one another in a direction perpendicular to the longitudinal extent of the semi-finished profile (10). According to the invention, the metal strip (2) is trimmed before the first profiling process in such a way that it has a width that varies in the longitudinal direction.

Description

The present invention relates to a method for producing an elongated profile with a longitudinally varying cross section, in which an elongated metal strip having two strip edges, profiled in a first profiling process to a semi-finished profile and then in sections in a second profiling process is embossed such that at least two sections are offset in a direction perpendicular to the longitudinal extent of the semi-finished profile against each other.

The use of profiles with varying cross section is required in various technical fields. For example, it is necessary to introduce a load into the profile at a certain point of the profile. The cross section of the profile must at this point or in adjacent areas u. U. be enlarged so that the profile is structurally suitable for receiving the loads. It may also be necessary for the cross-section to be reduced at a certain point, for example in order to attach a specific attachment to the profile at this point, or to simply make room for other components which need not necessarily be connected to the profile. which would otherwise collide with the profile. A prime example of the use of profiles with varying cross section is the automotive industry. It is not uncommon that certain carrier profiles for reasons of space at certain locations must have recesses, so that at this point, for example, cable guides or the like can be passed on the profile.

A method for producing an elongated profile with varying cross section is for example out EP 1547922 B1 known. The method requires as starting material a sheet which has a special shape and is formed into a closed profile with a special roll profiling device in several steps. The roll forming system must be equipped with specially adjustable rollers. With the method, only continuous cross-sectional changes can be realized, a more or less erratic change in the cross section can not be generated.

A method of the type mentioned is, for example EP 1344583 B1 known. In this method, a profiled strip is first produced from a flat strip by rolling and then partially embossed in such a way that at least two sections in a direction perpendicular to the longitudinal extent of the band are offset from each other. The profiled strip is trimmed after embossing such that the staggered portions have a different cross-section. The reason for the production of the different cross sections is thus the last process step of trimming.

This in EP 1344583 B1 The disclosed method has the disadvantage that the trimming of the profile may be difficult under certain circumstances, especially with complex profile cross sections. In addition, this process deforms areas of the starting material which are subsequently cut away. This requires a relatively high forming work and may have the consequence that during the stamping process unfavorable flow behavior of the material occurs.

The object of the present invention is to improve the method of the type mentioned and to avoid the problems mentioned.

The object is achieved by the features of independent claim 1. Accordingly, in the method mentioned above, an inventive solution to the problem, if the metal strip is trimmed prior to the first profiling process such that it has a varying width in the longitudinal direction. The inventive method has the advantage that the metal strip can be trimmed right at the beginning of the process so that a subsequent trimming is no longer required. The trimming of the still unprofiled metal strip is particularly simple and can be done both in a stamping press as well as in a rolling mill. It can be provided that a plurality of sections are offset from each other at regular intervals. For example, the finished profile can thereby obtain a tinned shape.

Advantageous embodiments of the present invention are the subject of the dependent claims.

In a particularly preferred embodiment of the present invention, the metal strip is trimmed in such a way that the strip edges run continuously straight after the second profiling process. As a result, for example, a U-profile with varying profile height can be created, wherein the band edges run on the opening side of the profile at a constant level. Continuous straight strip edges may also be desired if the strip edges, for example, in a subsequent Continuous process further processed, for example, bent or rolled or welded together. In order to obtain continuous straight strip edges, the trimming of the metal strip must correspond to the offset. At a point where the finished profile has more material, the trimmed metal strip must also have a greater width than elsewhere.

In a further preferred embodiment of the present invention, the metal strip is profiled in the first profiling process to form an open semi-finished profile. An open semi-finished profile can be in the second profiling process at the desired locations against each other, without causing warping or wrinkling. Overall, this simplifies the further process. Most preferably, the metal strip is profiled in the first profiling process to a U-profile. Further preferably, the U-profile is embossed in the second profiling process such that the at least two mutually offset portions are offset in a direction perpendicular to the bottom of the U-profile against each other. Thus, it is the bottom of the U-profile, which undergoes a level variation in the second profiling process and can be formed, for example staircase or crenellated. The metal strip can be profiled in the first profiling process, for example, to a pure V-profile or a V-profile with additionally angled, mutually parallel leg ends. The bottom of the profile is in this case V-shaped.

In order to increase the stability of the U-profile or V-profile, it can further be provided according to the invention that the U-profile is reshaped into a hat profile after the second profiling process in a third profiling process by forming the legs of the U-profile or V Profiles are bent over in the area of their ends. If the trimming of the starting material, as described above, is carried out in such a way that the band edges run continuously straight after the second profiling process, this results in a hat profile with a constant width and varying profile height.

In a further preferred embodiment of the present invention, the semi-finished profile is formed after the second profiling process in a third profiling process to form a closed hollow profile. This gives a particularly stable hollow profile with varying profile height. Preferably, the band edges are then welded or soldered together, in particular to the stability of the finished Continue to increase profile. The final transformation to the closed hollow profile can be carried out, for example, in the cold rolling process.

In a further preferred embodiment of the present invention, the first profiling process is carried out in the cold rolling process. For example, this can be produced in a particularly simple manner in the first profiling a U-profile. Depending on the material thickness and / or complexity of the semi-finished profile to be created, the first profiling process can preferably take place in several profiling steps. For example, it may be advantageous for the microstructure if a particularly pronounced change in shape, for example bending over 90 °, does not take place in one step but in several steps.

Alternatively, it is also conceivable to carry out the first profiling process in any pressing device, for example in a hydraulic press. Also, several profiling steps can be provided. It is particularly advantageous if both the trimming step and the first profiling process are carried out in an intermittent method with a stamping press. This makes it possible to prefabricate even longer profiles quickly and inexpensively.

In a further particularly preferred embodiment of the present invention, the second profiling process also takes place in a pressing device, and thus in an intermittent, non-continuous process. First, this does not require a change or at least no further change to another profiling device. In addition, in a press, in particular in a deep-drawing press, a particularly large and, if desired, step-shaped offset can be generated. Alternatively, it is of course possible to perform the second profiling process in a continuous rolling process. For this purpose, special rolls may preferably be provided with form-stamping elements on the outer circumference. Regardless of whether the second profiling process takes place in a pressing device or in the rolling mill, it is also advantageous here if the second profiling process is composed of several profiling steps, in particular if a particularly pronounced offset is to be generated.

The inventive method is particularly suitable for producing metal profiles from a flat, elongated metal strip. Preferably, steel profiles are produced by the method according to the invention.

It should be noted that the length of the profiles can be determined already at the beginning of the process by cutting to length a correspondingly long sheet metal strip, or after the actual profile production process by cutting to length the finished profiles.

The invention will be explained in more detail below with reference to drawings.

Fig. 1

ein längliches Profil mit einem in Längsrichtung variierenden Querschnitt, herstellt nach dem erfindungsgemäßen Verfahren,

Fig. 2

ein längliches Metallband als Ausgangsmaterial zur Herstellung des Profils aus Fig. 1,

Fig. 3

das Metallband aus Fig. 2 nach dem Besäumungsvorgang,

Fig. 4

das zu einem U-Profil umgeformte Metallband aus Fig. 3,

Fig. 5

das U-Profil aus Fig. 4 nach einem weiteren Umformschritt mit bereits leicht gegeneinander versetzten Abschnitten,

Fig. 6

das U-Profil aus Fig. 5 nach einem weiteren Umformschritt, und

Fig. 7

eine schematische Darstellung eines Walzenpaars zur Erzeugung der gegeneinander versetzten Abschnitte in einem Kaltwalzwerk.

Show it:

Fig. 1

an elongated profile with a longitudinally varying cross-section, produced by the method according to the invention,

Fig. 2

an elongated metal strip as a starting material for the production of the profile Fig. 1 .

Fig. 3

the metal band off Fig. 2 after the trimming process,

Fig. 4

the formed into a U-shaped metal band Fig. 3 .

Fig. 5

the U-profile off Fig. 4 after another forming step with sections already slightly offset from one another,

Fig. 6

the U-profile off Fig. 5 after another forming step, and

Fig. 7

a schematic representation of a pair of rollers for generating the staggered sections in a cold rolling mill.

For the following statements applies that the same parts are designated by the same reference numerals. If reference signs are contained in a representation which are not discussed in more detail in the associated description of the figures, reference is made to preceding or subsequent description of the figures.

Fig. 1 shows an elongated profile 1, which has been prepared by the process according to the invention. The profile is a so-called hat profile, which in the Has substantially the shape of a U-profile with outwardly bent legs 9. In the figure it can be seen that the profile has a plurality of sections 4 and 5, which are offset from each other perpendicular to the longitudinal extent of the profile. The staggered sections alternate each other in the longitudinal direction of the profile. More specifically, the portions 5 are offset outwardly from the intermediate portions 4 with respect to the bottom of the hat profile. The sections 5 are thus crenellated outward. As the figure shows, the outwardly bent legs 9 are not affected by the offset. The outer edges 3 of the hat profile are continuous straight.

In the following, the method for producing the in Fig. 1 shown profile explained in more detail. The profile is made of a simple elongated metal band, which is preferably made of steel. The elongated metal band is in Fig. 2 shown schematically and can be supplied to the device for producing the profile, for example via a reel, from which it is unrolled. The metal strip can be cut to a certain length before the actual profile production. As Fig. 2 shows, the metal strip 2 is substantially straight, even the two band edges 3 of the metal strip are formed straight straight and parallel to each other.

In a first method step, the metal strip is first trimmed, in such a way that it subsequently has a width which varies in the longitudinal direction. The trimming of the metal strip is preferably carried out in a conventional manner in a stamping press. The trimmed metal strip 2 is in Fig. 3 shown. It can be seen that the two band edges 3 now no longer run straight. Rather, recesses 6 are formed in sections in the band edges, which in the region of the sections 4 to be created later in FIG Fig. 1 shown profile lie. The shape of the transition between the recesses and the areas in which the band edge 3 remains un-trimmed depends largely on how exactly the transition between the staggered sections 4 and 5 should be designed.

The trimmed metal strip 2 is formed in the next step to a simple U-profile. The resulting U-profile 10 is in Fig. 4 displayed. The U-profile has a continuous straight bottom 7, as well as two projecting at right angles from the ground leg 8. The transformation to the U-profile is preferably carried out in the line in the cold rolling process and may include several forming steps. Especially If the metal strip has a very large material thickness, it is recommended that the legs 8 bend gradually. The transformation to the U-profile can of course also be done by means of another suitable pressing device. For example, it is possible to transform metal strips with low material thickness in a deep-drawing press to the U-profile.

At the transformation to the U-profile is followed by a further transformation, with which the in Fig. 1 shown staggered sections are generated. This profiling process can be done in several profiling steps, which is particularly necessary if two sections of the profile are to be particularly strongly offset from each other. The displacement preferably takes place in a deep-drawing press. Fig. 5 shows the U-profile 10 after a first deep-drawing process, in which initially a slight offset between the sections 4 and 5 is generated. The figure shows that the depth of the recesses 6 in the band edge 3 has already been reduced after the first deep-drawing operation. In Fig. 6 the same U-profile is shown after another embossing process. The offset between the two sections 4 and 5 now already corresponds to the desired offset. The recesses 6 in the band edge 3 are now gone after the further offset of the profile. The band edges 3 are now again straight straight, just as in the starting material, namely the metal strip 2 Fig. 2 ,

To do that in Fig. 1 To obtain shown finished hat profile, now only the ends 9 of the two legs 8 of the hat profile along the in Fig. 6 indicated bending lines 11 are bent by about 90 ° to the outside. This process can equally easily be done either in a rolling mill or in a pressing device.

Fig. 7 Finally, shows a schematic representation of a pair of rollers 12/13 for generating the offset between the sections 4 and 5 in a rolling mill. The illustration shows both the pair of rollers and the still undeformed U-profile 10 each in longitudinal section. In the case shown, the offset in the profile interior sections 4 are generated by pressing the tread 7. The upper roller 12 of the roller pair has on its outer periphery to an outwardly projecting punch 15. The lower roller 13 has on the outer circumference via a recess 16, in which the punch 15 engages. The U-profile is stabilized during the embossing process by a plurality of roller pairs, not shown. Also, the upper roller 12 of the pair of rollers shown has a stabilizing edge 14, with which the respective leg 8 of the U-profile is stabilized or held during the embossing process.

Claims (10)

Method for producing an elongated profile (1) with a longitudinally varying cross section, in which an elongate metal strip (2) having two strip edges (3) is profiled to a semi-finished profile (10) in a first profiling operation, the semi-finished profile (10) 10) is subsequently embossed in sections in a second profiling process in such a way that at least two sections (4, 5) are offset from each other in a direction perpendicular to the longitudinal extension of the semi-finished profile (10), characterized in that the metal strip (2) before the first profiling process is trimmed to have a longitudinally varying width. A method according to claim 1, characterized in that the metal strip (2) is trimmed in such a way that the strip edges (3) extend continuously straight after the second profiling process. A method according to claim 1 or 2, characterized in that the metal strip (2) in the first profiling process to an open semi-finished profile (10) is profiled. A method according to claim 3, characterized in that the metal strip (2) is profiled in the first profiling process to a U-profile (10) or to a V-profile. A method according to claim 4, characterized in that the U-profile (10) or V-profile is embossed in the second profiling process such that the at least two mutually offset portions (4, 5) in a direction perpendicular to the bottom (7) of the U Profiles (10) or the V-profile are offset from each other. A method according to claim 5, characterized in that the U-profile (10) after the second profiling process in a third profiling process to a hat profile (1) is formed by the legs (8) of the U-profile (10) or the V Profiles in the area of their ends (9) are bent. Method according to one of claims 1 to 5, characterized in that the semi-finished profile (10) after the second profiling process in a third profiling process is formed into a closed hollow profile. A method according to claim 7, characterized in that the strip edges (3) are subsequently welded or soldered together. Method according to one of claims 1 to 8, characterized in that the first profiling takes place in the cold rolling process. Method according to one of claims 1 to 9, characterized in that the second profiling process takes place in a pressing device.

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