EP2208555A1 - Rolling method and rolling device for producing a metal strip with a thickness that is variable across its width - Google Patents

Abstract

The method involves producing a recess in a group (A) of roll forming tools (1, 2) by a form roller on a surface of a flat metal strip (5), and reducing thickness of the flat metal strip. The recess with another recess of one of the two form rollers is widened to a thinned region of the metal strip in groups (b, c, d) of the roll forming tools. A motion direction (4) of the former recess is changed by the metal strip along a surface of the roll forming tool engaged in the former recess, where the surface rolls on the metal strip. An independent claim is also included for a rolling device for manufacturing a metal strip.

Description

The invention relates to a rolling method and a rolling apparatus for producing a metal strip having a width varying over its width from a flat metal strip by means of a number of groups of roll forming tools arranged in line one behind another according to the preambles of claims 1 and 7.

Here, a group of roll forming tools comprises at least one forming roller which generates at least one first recess on at least one surface of the metal strip in which the thickness of the strip is reduced. In subsequent groups of roll forming tools, there are further forming rollers which gradually widen this first recess with further punctures to a thinned area of the metal strip.

Metal sheets or sheet metal parts made from metal strips are used in many fields of engineering such as the automobile industry, household and consumer goods industry and the like. Depending on the field of application, the sheets or sheet metal parts are formed into profiles, in which case roll profiling methods are to be mentioned in particular which produce metal profiles by means of profiling machines with a plurality of roll forming tools made of metal strips.

In many applications, for example in vehicle construction, but also in other fields, it is endeavored to keep the material thickness of the metal sheets and metal profiles used as low as possible, on the one hand material costs and on the other hand to save weight. This can be achieved in a very efficient manner by using, as starting material for the sheets, sheet metal parts or profiles, metal strips which have a thickness varying over their width. The material thickness of the component produced therefrom can then be adapted specifically to the loads to be expected in the case of use, wherein a higher material thickness is provided in areas of higher load, while the areas are formed thinner with less stress. The thereby achievable weight and material savings at the same time optimal component strength is obvious.

Sheet metal, sheet metal parts and profiles with load-adapted thickness structure were formerly often produced by welding techniques. In this case, sheet metal parts of different thicknesses are butt welded together, or reinforcing plates are welded onto particularly stressed areas of a component that is too thin in itself. However, this procedure is not optimal under several aspects. Because the additional welding process generates significant additional costs. Furthermore, a weld always represents a weak spot in the component due to the thermal structural changes produced during welding.

In the DE 101 13 610 A1 It has been proposed to make a metal strip having a thickness varying across its width from a flat metal strip by means of a number of groups of roll forming tools arranged in line one behind another, without having to use welding methods. Here, first of all, a first shaping roller rolls a first recess into the surface of the metal strip, which locally reduces the material thickness of the metal strip by forming a groove-shaped impression. A number of subsequent forming rolls successively widen this first groove with further punctures to a thinned area, which accordingly runs along the entire metal strip. As a result, one obtains a metal strip with, for example, a thinned central region and two thicker edge regions, which can be cut into blanks, for example, or further processed into profiles having load-adapted material thicknesses. From this prior art, the present invention is based. When pressing the forming rollers in the material of the metal strip material is displaced. Care must be taken here that the displaced material flows as little as possible in the longitudinal direction of the metal strip, and that the flow of material is largely directed transversely to the direction of passage of the material strip, that is, the displaced material flows in the width direction of the metal strip. For a more than insignificant longitudinal flow of the displaced material inevitably leads to a wave formation in the manufactured variable-thickness metal strip. However, a material flow in the width direction is opposed by a spreading resistance of the metal strip. In addition to high reaction forces this is also disadvantageous because it leads in the areas next to the punctures to a material consolidation and thickening and consequently a bead formation. It is therefore necessary to lower the spreading resistance in order to facilitate a material flow in the width direction.

A solution to this problem is in the DE 10 2006 000 181 A1 disclosed. There, the output metal strip is provided with bends, which extend along the metal strip, and between which the reduction in thickness of the metal strip takes place. These turns reduce the width resistance so that the material displaced in the thickness reduction can flow outward in the width direction without much resistance. However, such a procedure either requires additional effort by attaching auxiliary bends, which subsequently have to be removed again - which is not optimal under stability aspects - or the method can only be used in special applications in which a profile with varying material thickness is to be produced anyway with the introduced for the reduction in thickness bends must be provided.

The present invention is therefore based on the object to further simplify or improve a rolling process and a rolling device of the type mentioned in relation to the problems described.

This object is achieved by a method having the features of claim 1 and by an apparatus having the features of claim 7. Preferred developments of the method emerge from the claims 2 to 6; advantageous embodiments of the device are set forth in claims 8 to 14.

The core of the present invention is therefore to be seen in the fact that the metal strip is bent out of its original direction of movement at least at the first puncture along a rolling on the metal strip surface of a roll forming tool involved in the puncture. Since the axis of the roll forming tool is necessarily transverse to the direction of movement of the metal strip, this results in a bending of the metal strip to a surface thereof, namely around the axis of the roll forming tool in a predetermined radius. This radius can be chosen so small that the metal strip is bent beyond its yield point, resulting in advantageous microstructural changes in the material. This is not necessary. In any case, the bend running transversely to the metal strip lowers the spreading resistance and leads to a slight flow of material of the material displaced during the penetration in the width direction. The attachment of a longitudinal auxiliary bend is unnecessary hereby.

The change of the direction of movement of the metal strip according to the invention when piercing upwards and downwards ("top" and "bottom" being the two directions corresponding to the normal on the surfaces of the metal strip) may preferably be effected by at least part of the roll forming tools are arranged alternately above and / or below the original direction of movement of the metal strip, that the direction of movement of the metal strip changes alternately upwards, in the original direction of movement and / or downwards. The metal strip can thus be guided by alternately up and down offset roll forming tools, so that it also alternately changes its direction; However, it can also be provided that the metal strip in each case two passes above and then two recesses arranged below the original direction of movement, so that it each bent at the first of the two equal punctures in the original direction of movement and the second of these punctures then down or is bent over at the top. It is only important in each case that the metal strip according to the invention changes its direction of movement when puncturing.

Such an arrangement may, in the context of the present invention, be such that the roll forming tools participating in the punctures are arranged in groups above and below the original direction of movement of the metal strip. In the simplest case, these are each a forming roll and a counter roll, which form a nip between them, and which together form the groups of roll forming tools of a recess. Accordingly, one group consisting of a form roller and an opposing roller can thus be arranged one behind the other, offset up and down, relative to one another.

It is particularly preferred if the roll forming tools are arranged in the manner of a straightening machine, that is, the roll forming tools are arranged offset in the working direction alternately above and / or below the original direction of movement of the metal strip and each roll forming with the two adjacent Rollformwerkzeugen each form a nip. Such a "straightening machine arrangement" is easy to store and the forces occurring in it are easy to control; In addition, Rollformwerkzeug radii can be selected, which bend the metal strip beyond the yield strength of his material out - at least initially - so that there is also a straightening effect for the metal strip, with the corresponding benefits, such as flatness and stress reduction of the final partially reduced thickness metal strip.

If in such a "straightening machine arrangement" no regular arrangement of the roll forming tools is selected, in particular between a forming roller and the first passed from the metal strip, cooperating with this form roller counter roll produced only with a part of the intended depth puncture can be made by the gap between the Form roller and this first counter-roller is chosen to be larger than the gap between the forming roller and the metal belt subsequently passed second counter-roller. Accordingly, the puncture is then deepened between the forming roller and the second passed counter-roller to the full desired depth. As a result, each puncture can thus take place in two stages, which is advantageous in avoiding bulging.

Particular advantages are within the scope of the present invention, when the roll forming tool, along the surface of the metal strip is guided during puncture, narrower than the metal strip or is shaped so that it rolls only in a limited puncture area around the puncture on the metal strip and the laterally adjacent areas of the metal strip when changing the direction of movement according to the invention are not supported or guided. Because this results in bending the metal strip up or down, around the axis of the corresponding roll forming tool around, to fold up or down the lateral, free metal strip areas. As a result, a kind of longitudinal auxiliary bend is formed without it having to be intentionally introduced into the material. A bending back of an auxiliary bend omitted, since the upwardly or downwardly deformed strip edges automatically revert back into the plane when the puncture has been left and the tape is transported in a straight line.

Figur 1

eine schematische Seitenansicht einer erfindungsgemäß ausgestal- teten Walzvorrichtung, reduziert auf eine schematische Darstellung der Rollformwerkzeuge, in einer ersten Variante;

Figur 2

eine Darstellung wie Figur 1, jedoch einer zweiten Variante;

Figur 3

eine Darstellung wie Figur 1, jedoch einer dritten Variante;

Figur 4

eine Darstellung wie Figur 1, jedoch einer vierten Variante;

Figur 5

eine schematische perspektivische Ansicht der Anordnung aus Figur 1;

Figur 6

drei nebeneinander angeordnete, schematische Frontansichten eines Walzspalts mit eingelegtem Metallband, wobei die nebenein- ander angeordneten Bilder hintereinander angeordneten Walzspal- ten entsprechen, gemäß dem Stand der Technik;

Figur 7

eine Darstellung wie Figur 6, jedoch eines erfindungsgemäßen Verfahrens;

Figur 8

eine Darstellung wie Figur 6, jedoch mit einer Modifikation gegenüber der Figur 7;

Figur 9

eine Darstellung wie Figur 6, jedoch mit einer Modifikation gegenüber den Figuren 7 und 8.

Several embodiments of a device according to the invention are described and explained in more detail below with reference to the accompanying drawings. Show it:

FIG. 1

a schematic side view of an inventively designed rolling device, reduced to a schematic representation of the roll forming tools, in a first variant;

FIG. 2

a representation like FIG. 1 but a second variant;

FIG. 3

a representation like FIG. 1 but a third variant;

FIG. 4

a representation like FIG. 1 but a fourth variant;

FIG. 5

a schematic perspective view of the arrangement FIG. 1 ;

FIG. 6

three juxtaposed, schematic front views of a roll gap with metal strip inserted, wherein the juxtaposed images correspond successively arranged roll nips, according to the prior art;

FIG. 7

a representation like FIG. 6 but a method according to the invention;

FIG. 8

a representation like FIG. 6 , but with a modification to the FIG. 7 ;

FIG. 9

a representation like FIG. 6 , but with a modification to the FIGS. 7 and 8 ,

FIG. 1 shows a total of six pairs of roll forming tools, each consisting of a forming roller 1 and a counter-roller 2, which each form a nip 3 between them. Each pair of roll forming tools 1, 2 forms a group a, b, c ... of roll forming tools through which a metal strip (not shown) is passed. The direction of movement 4 of this metal band lies in the plane of the drawing and is directed from left to right. The groups a, b, c ... of roll forming tools are alternately offset upwards and downwards relative to the direction of movement 4 of the metal strip, so that the metal strip is alternately deflected downwards and upwards when passing through the individual roll gaps 3, in the Area in which the forming rollers 1 each generate at least one recess in the surface of the metal strip. In the first group a, the metal strip is deflected downwards, guided along the counter-roller 2, while it is deflected upwards in the group b, here guided by the forming roller 1. This is repeated periodically over the further groups c ff ,

It should be noted at this point that the individual groups a, b, c of roll forming tools do not necessarily have to be offset alternately upwards or downwards in order to bring about the change according to the invention of the direction of movement of the metal strip. Rather, the first two groups a, b at the same height, then the third and fourth groups c, d offset to the same height, then the fifth and sixth groups e, f again approximately at the height of the first two groups a, b, etc. The wrap angle of the metal strip to the Rollformwerkzeug 1, 2, where it is guided in the puncture, thereby reduced, although there is still a deflection at each stitch.

In FIG. 2 is an arrangement of the roll forming tools 1, 2 illustrated by the "straightening machine principle". Here, an upper row of forming rollers 1 and a lower row of counter rollers 2 constitute the individual groups a, b, c ... of roll forming tools, each group being formed by two counter rollers 2 and a forming roller 1. The form roles of the middle groups b, c ... thus each belong to two groups. The (not shown here again) metal strip is guided as in a straightening machine along each roll forming tool 1, 2 and thereby deflected in each case in the formed between the roll forming tools 3 columns.

A variation of this straightening machine arrangement is in FIG. 3 shown. Here, the gaps 3 between the forming rollers 1 and the counter rollers 2 of each individual group a, b, c... Of roll forming tools have different widths, so that the gap 3 passed first between the forming roll 1 and the metal strip (again not shown here) first counter-roller 2 is larger than the gap 3 'between the forming roller 1 and the second counter-roller 2' of the group a, which subsequently passes from the metal belt. The puncture of the forming roller 1 of this first group a in the surface of the metal strip thus takes place in two stages, in the first gap 3 initially only up to a certain depth, which is a fraction of the desired depth, and then in the second gap 3 'completely up to the desired depth , This geometry continues in the following groups b, c, d ..., so that each puncture takes place in two stages.

Another variation of an inventive arrangement of roll forming tools 1, 2 shows FIG. 4 , Here are four pairs of forming rollers 1 and counter rollers 2, which each form a nip 3 between them, arranged one behind the other, as usual in the prior art such that the roll nips 3 are arranged horizontally in the same plane. The inventive Deflection of the (here again not shown) metal strip is effected by between the groups a, b, c, d of roll forming tools 1, 2 deflection rollers 9. Because in order to get from the nip 3 of the first Rollformwerkzeuggruppe a to the nip 3 of the second Rollformwerkzeuggruppe b, the metal strip must be guided around the bottom guide roller 9 or below. This causes the metal strip in each nip 3 to be deflected either upwards or downwards, with a bending radius corresponding to the radius of either the forming roll 1 or the counter roll 2.

FIG. 5 shows the arrangement of roll forming tools 1, 2, already in FIG. 1 is shown, in a schematic perspective view, in which case a metal strip 5, which passes through the individual rolling nips 3 of Rollformwerkzeuggruppen a, b, c, is shown. In this way, a special feature of a preferred embodiment of the present invention is illustrated, which then occurs when the forming rollers 1 and counter rollers 2 have a smaller width than the metal strip 5: The then not guided by the roll forming tools 1, 2 edge regions 6 of the metal strip 5, the up and down movement of the metal strip 5 not to go through the individual roll nips 3, but to remain in the original plane of movement of the metal strip 5. This leads to a folding or folding down of these edge regions 6 of the metal strip 5, in particular during its passage through the roll nips 3, so that the spreading resistance at the roll nips 3 is further reduced.

The basis FIG. 5 just described process of folding up and down the edge portions 6 of the metal strip 5 in an inventive arrangement of roll forming tools is based on the FIGS. 6 to 9 further clarified. Strictly speaking, this is only in the FIGS. 7 to 9 the case, there FIG. 6 essentially corresponds to a method according to the prior art and thus is suitable to illustrate the general principle of the present rolling process according to the invention:

The in the FIGS. 6 to 9 each juxtaposed representations are schematic plan views of actually arranged one behind the other, from each of a forming roller 1 and a counter-roller 2 existing Rollformwerkzeugpaare a, b, c, each forming a nip 3 between them.

In the roll forming tool group a in FIG. 6 a first puncture in the metal strip 5 is generated, by a molded onto the forming roller 1 pressing ring 7. This push ring 7 presses into the metal strip 5 and generates a groove 8 of 7 'and 7 "of the Rollformwerkzeuggruppen b and c Subsequently, successively expanded to a portion of the metal strip 5 with reduced thickness.

FIG. 7 shows a direct comparison of the effect of the invention, in this case offset in height arrangement of Rollformwerkzeuggruppen a, b and c, here the roll forming tool group b set lower and thus the formed there nip 3 below the original plane of movement of the metal strip 5, while the Rollformwerkzeuggruppen a and c are set higher. Since the forming rollers 1 and the counter rollers 2 are less wide than the metal strip 5, this staggered arrangement of Rollformwerkzeuggruppen a, b, c to fold down or fold up the free, non-guided areas 6 of the metal strip 5, which is the width flow of in the Groove 8 displaced material in addition to inventively provided change of direction of the metal strip 5 in the nip 3 facilitates.

This effect can be enhanced when the push ring 7 ( FIG. 8 ) or two pressure rings ( FIG. 9 ) is arranged to generate the groove 8 respectively directly on the outer edge of the forming roller 1, as the FIGS. 8 and 9 demonstrate. This requires that the shaping rollers 1 of the respectively following roll forming tool groups b, c each have to be formed somewhat wider than those of the respective preceding roll forming tool groups a, b, so that the groove 8 widens successively. Characterized in that the groove 8 is disposed immediately adjacent to the point at which the edge portion 6 of the metal strip 5 bends downwards or upwards, the effect of folding up or folding down the edge regions 6 of the metal strip 5 is optimally utilized to reduce the Breitungswiderstandes.

Claims (14)

A rolling method of producing a metal strip having a thickness varying over its width from a flat metal strip (5) having a number of groups (a, b, c ...) of roll forming tools (1, 2) arranged in line one behind the other, successively from the metal strip (5), wherein in a group (a) of roll forming tools (1, 2) by means of a forming roller (1) on at least one surface of the metal strip (5) at least a first recess (8) is generated, in which the thickness of Bandes (5) is reduced, and wherein in subsequent groups (b, c, d ...) of roll forming tools of this first recess (8) with further punctures (8) of further forming rollers (1) to a thinned portion of the metal strip (5 ) is widened,
characterized,
that the metal strip (5) at least in the first recess (8) involved in its direction of movement along a on the metal strip (5) rolling on the surface of a recess (8) roll-forming tool (1, 2) changes. Rolling method according to claim 1,
characterized,
in that the change in the direction of movement takes place with a bending radius which causes bending of the metal strip (5) beyond its yield point. Rolling method according to one of claims 1 or 2,
characterized,
in that the metal strip (5) is guided between roll forming tools (1, 2) arranged alternately above and / or below its original direction of movement (4) so that its direction of movement moves alternately upwards, in the original direction of movement (4) and / or downwards changes. Rolling method according to claim 3,
characterized,
in that the metal strip (5) is guided through a roll forming tool arrangement which comprises roll forming tools (1, 2) offset in the working direction (4) and alternately above and / or below the original direction of movement (4) of the metal strip. Rolling method according to claim 4,
characterized,
in that in each case one forming roller (1) cooperates with two counter-rollers (2, 2 '), and that between the forming roller (1) and the first counter-roller (2) passed by the metal strip (5) there is a puncture provided only with a part of the intended depth ( 8) which is subsequently deepened to the full intended depth between the forming roll (1) and the second counter roll (2 ') passed by the metal strip (5). Rolling method according to at least one of claims 1 to 5,
characterized,
that a roll forming tool (1, 2) is used as a roll forming tool (1, 2), along the surface of which the metal strip (5) is guided at the recess (8), the surface of which is only in a limited recess area around the groove (8) on the Rolls off metal strip (5), while the areas (6) of the metal strip (5) lying laterally next to the puncture area are not supported or guided by this roll forming tool (12). Rolling device for producing a metal strip with a thickness varying over its width from a flat metal strip, in particular for carrying out the method according to at least one of claims 1 to 6, with a number of groups arranged in line one behind another (a, b, c. of roll forming tools (1, 2) which are successively traversed by the metal strip (5), wherein a group (a) of roll forming tools (1, 2) comprises at least one forming roll (1) having at least one first recess (8) in a surface of the metal strip (5) to reduce the thickness of the metal strip (5) there, and wherein at least some subsequent groups (b, c, d ...) of roll forming tools (1, 2) further form rollers (1) containing widening the first recess (8) successively to a thinned area of the metal strip (5) by further recesses (8),
characterized,
that the metal strip (5) at least in the first recess (8) along a on the metal strip (5) rolling surface of the recess (8) involved roll forming tool (1, 2) is performed and during the puncture (8) thereby changes its direction of movement. Rolling device according to claim 7,
characterized,
in that the surface of the rollforming tool (1, 2), along which the metal strip (5) is guided, has a radius which causes the metal strip (5) to bend beyond its yield point. Rolling device according to one of claims 7 or 8,
characterized,
in that at least a part of the roll forming tools (1, 2) is arranged alternately above and / or below the original direction of movement (4) of the metal strip (5) so that the direction of movement of the metal strip (5) alternately upwards, in the original direction of movement ( 4) and / or changes down. Rolling device according to claim 9,
characterized,
in that at least a part of the roll forming tools (1, 2) is combined in a roll forming tool arrangement comprising roll forming tools (1, 2) offset in the working direction, alternately above and / or below the original direction of movement (4) of the metal strip (5) , Rolling device according to claim 10,
characterized,
in that one forming roller (1) cooperates with two counter-rollers (2, 2 '), and that the gap (3) between the forming roller (1) and the first counter-roller (2) first passed by the metal strip (5) is greater than the gap (3 ') between the forming roller (1) and the second counter roller (2') subsequently passed by the metal strip (5). Rolling device according to claim 9,
characterized,
that at least a part of the groups (a, b, c ...) of roller shaping tools (1, 2) so alternately in groups above and / or below the original direction of movement (4) of the metal strip (5) are arranged such that the direction of movement of the Metal band (5) alternately upwards, in the original direction of movement (4) and / or changes down. Rolling device according to at least one of claims 7 to 12,
characterized,
that the roll forming tool (1, 2), along the surface of which the metal strip (5) is guided at the puncture (8), only rolls around the puncture (8) on the metal strip (5) in a limited puncture area, while it rolls along the side of the metal strip (5) Penetration area lying areas (6) of the metal strip (5) does not support or leads. Rolling device according to at least one of claims 7 to 13, characterized
in that the groups (a, b, c...) of roll forming tools each consist of a forming roll (1) and at least one counter roll (2), each of which forms a roll gap (3) between them.

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