EP2094412B1 - Component made of a flat material and method for the production thereof - Google Patents

Description

Territory of invention

The invention relates to a component made of a flat material with a located between two main surfaces parallel to each other central surface, wherein the flat material is provided with a deformation structure which extends in the manner of a pressure partially perpendicular to the central surface according to the preamble of claim 1. Such is the Deformation structure is introduced in the main shape direction perpendicular to the central surface and will generally have the characteristic for Beulmuster parabolic depressions relative to the central surface, while the Beulränder at least partially with respect to the central surface have a directed against the main shape, grandeur.

Background of the invention

Components of this type are for example of the generic type DE-C2-100 06 348 or the DE-A1-197 50 576 The latter describes a method for the production of buckling structures in the rolling process. According to DE-C2, the deformation structure essentially serves to increase the rigidity of the flat material, but there the stiffening effect is reduced by concentric counterbumps introduced at the bottom of the bump. Also at DE-297 12 622 U1 serves the structuring of the stiffening of the sheet. Such a stiffness increase is according to the DE-A1-197 50 576 especially for vehicle construction, but in principle also for all flat components, of interest.

A disadvantage of the known components is that their increase in stiffness soon reaches its limits. Therefore, this invention is based on the object, a component of the type mentioned in such a way that it has a greater rigidity.

Summary of the invention

According to the invention this is done by a component having the features of claim 1. This results in a structure that is designed not only bulging in the pressing direction, but also against the pressing direction relative to the central surface at least partially has a sublime in the Beulrändem. Both deformations, so the Bumps in combination with the grandeur of the edge zones result in a higher resistance to applied bending stresses. This combination of buckling reinforcement and the partial grandeur of the Beulränder is also the local stretching of the sheet is increased in the region of a bump to be created, whereby an additional stiffening effect is caused.

In addition, it is characteristic of this method that the sublimation of the bulge under the pressure effect creates a stretch and slight bending in the bulge region, which increases the local instability and causes the bulges to spring in more or less spontaneously even under a very low pressure effect. This considerably reduces the compression forces required for structuring in comparison to embossing methods.

Furthermore, this method can be integrated as a secondary feature in deep drawing or stretching operations known per se, etc., and allows flat edge zones adjacent to the structural form field. It also makes possible a subsequent, possibly partial, further deformation of pre-formed components. The determination of the optimal cell size according to the invention is carried out according to the principle of minimum energy expenditure for buckling and can be carried out on the basis of finite element analyzes.

Flat materials having this structure moreover have a more favorable influence on the vibration and flow behavior, e.g. at ventilation ducts.

The structural form tool can be constructed from modules that allow for flexibilization of assembly, reduction of manufacturing costs and improvement of maintenance.

The invention further relates to a method for producing such a component, which has the features of claim 4.

In this case, in the context of the invention, the pressing force for generating the bumps and the grandeur of the Beulrandzonen on elastic active media (or the like) is applied to the component. The targeted generation of local instabilities also causes the bumps to jump abruptly into the cavities of the tool and shape their geometry independently (freely) and paraboloidally, so that not, as in a stamping process, the bumps are formed in a correspondingly shaped cavity of the counter-tool.

Brief description of the drawings

Fig. 1a

eine Perspektivansicht,

Fig. 1b

eine Draufsicht,

Fig. 1c

einen Schnitt nach der Linie A-A der Fig. 1b, und

Fig. 1d

ein Detail B der Fig. 1c in größerem Maßstab einer bevorzugten Ausführungsform eines erfindungsgemäßen Bauteiles;

Fig. 2a

eine Perspektivansicht dreier Zellen an einem erfindungsgemäßen Bauteil in einer gegenüber Fig. 1a vergrößerten Darstellung, zu der die

Fig. 2b

eine schematisierte Ansicht liefert, in welcher gewölbte, höhere Zellbiegeränder strichliert, dagegen gerade, niedrigere Zellbiegeränder mit vollen Linien dargestellt sind; an Hand der

Fig. 3a bis 3c

soll an Hand von Schnittdarstellungen die Vorgangsweise nach dem Stande der Technik und nach dem erfindungsgemäßen Verfahren erläutert werden, wobei Fig. 3a das unverformte Flachmaterial zeigt, Fig. 3b eine zellenartige Verformungsstruktur nach dem Stande der Technik, und Fig. 3c eine erfindungsgemäß hergestellte Verformungsstruktur veranschaulichen;

Fig. 4

zeigt einen möglichen Typ des im Rahmen des Verfahrens der Erfindung verwendbaren Pressengestells zur Einbringung des Strukturfeldes;

Fig. 5

zeigt schematisch den Vorgang einer Tiefzieh-Hauptformgebung für das Bauteil mit einer gleichzeitigen Strukturverformung im Bereich des Tiefziehbodens;

Fig. 6

zeigt, an Hand einer leicht gekrümmten Formfeldstruktur, die Pressanordnung mit einer über eine Elastomerplatte erfolgende Druckaufbringung und einem mit eingearbeiteten Kavitäten gemäß der zu erzeugenden Struktur versehenen Werkzeugboden (die Anordnung kann auch umgekehrt werden);

Fig. 7a

stellt eine isometrische Ansicht eines modularen Eckbereichs-Aufbaues eines Formfeldstrukturwerkzeuges dar, welcher als Nebenformelement in bevorzugt verwendeten Tief- oder Streckziehwerkzeugen integrierbar ist, wozu

Fig. 7b

eine Seitenansicht von links,

Fig. 7c

eine Draufsicht, und

Fig. 7d

eine Seitenansicht von oben veranschaulicht.

Further details of the invention will become apparent with reference to the following description of exemplary embodiments shown schematically in the drawing. Show it:

Fig. 1a

a perspective view,

Fig. 1b

a top view,

Fig. 1c

a section along the line AA the Fig. 1b , and

Fig. 1d

a detail B of the Fig. 1c on a larger scale a preferred embodiment of a component according to the invention;

Fig. 2a

a perspective view of three cells on a component according to the invention in a opposite Fig. 1a enlarged view, to which the

Fig. 2b

provides a schematic view in which dished, higher Zellbiegeränder dashed, while straight, lower Zellbiegeränder are shown with solid lines; based on

Fig. 3a to 3c

will be explained on the basis of sectional views of the procedure according to the prior art and the inventive method, wherein Fig. 3a shows the undeformed sheet, Fig. 3b a cell-like deformation structure according to the prior art, and Fig. 3c illustrate a deformation structure prepared according to the invention;

Fig. 4

shows a possible type of press frame used in the method of the invention for introducing the structure field;

Fig. 5

shows schematically the process of a thermoforming main molding for the component with a simultaneous structural deformation in the region of Tiefziehbodens;

Fig. 6

shows, on the basis of a slightly curved shape field structure, the pressing arrangement with an over an elastomeric plate pressure application and a with incorporated cavities according to the structure to be produced provided tool bottom (the arrangement can also be reversed);

Fig. 7a

FIG. 4 illustrates an isometric view of a modular corner region structure of a form field structure tool that can be integrated as a minor feature in preferred deep drawing or ironing dies, including: FIG

Fig. 7b

a side view from the left,

Fig. 7c

a plan view, and

Fig. 7d

a side view illustrated from above.

Detailed description of the drawings

A produced deep-drawn component 1 ( Fig. 1a ) has a smooth flange 2, while a structural field 4 itself, including the elevations of Zellbiegeränder 14, in the context of a deep drawing operation in the sheet material (sheet metal or plastic) is introduced as a slightly raised auxiliary element 3. The deformation structure 4 preferably has the form of a periodic lattice of cells, for example hexagonal cells 5, arranged next to one another.

It should be noted that although the arrangement of hexagonal cells is preferred, the invention is by no means limited thereto. Because it is quite possible within the scope of the invention to provide instead of a continuous grid also on the deep-drawn bottom surface of the component 1 distributed individual, in particular cell-like deformations, although it is of course clear that in the illustrated complete grid, the stiffening effect is greater. In addition, cells need not be hexagonal, but may also consist of triangles, rectangles, double trapezoids, rhomboids, as well as rhomboid, octagonal, with two opposing webs stretched (ie asymmetric) hexagons, etc., with straight or curved edges that the Surround recesses. In doing so, aesthetically pleasing patterns can be achieved with curved bars. Combinations with differently shaped cells or bump edges are also possible.

Thus, while, as can be seen, the deep-drawing tray contains the three-dimensional deformation structure 4, the material (sheet metal, it can also be plastics) remains in the deep-drawing flange 2 (due to the action of the tool holder) its flat shape. On the other hand, the built in the segments of Tiefziehwerkzeuges sublimities lead to an increase of the Zellbiegeränder 14th

In Fig. 2a and b For example, three of the hexagonal cells 5 are contiguous and enlarged. The arrangement of the hexagonal cells is expedient, as is known from honeycombs, because usually the largest stiffening is achieved. The special feature of this embodiment is the structure of the individual cells. For example, if there is a longitudinally oriented sheet metal workpiece, usually the diagonal Beulbegrenzungsstege in the longitudinal direction, the transverse webs oriented at right angles to the longitudinal axis. The special design of the in the Fig. 2a, 2b cell 5 is now that the diagonal boundary webs or Zellbiegeränder 14 are provided with the main shape direction opposing arches, ie with respect to the central surface 8 plus the proportionate material thickness 12 have a sublimity ( Fig. 2b ), while the transverse webs 15 are lower and have no elevations ( Fig. 2b ), so complete with the main surface 7 of the sheet. The excessive diagonal cell boundary webs thus form a line 16, namely a zigzag line, which extends over the entire structured field surface of the workpiece 4 and also already in 1a can be seen. In general, the arrangement of these webs is arbitrary, preferably in line form, but produces the greatest effect in the zig-zag arrangement.

The Fig. 3a shows the position of the major surfaces 7, 9 of the sheet before deformation, wherein the sheet has a central surface 8 and a material thickness 12.

On the basis of enlarged illustrations in Fig. 3b and 3c Now, the effect achieved according to the invention over a sheet metal according to the prior art will be illustrated. The Fig. 3b shows a deformation structure with a cell 5 in a flat material having the central surface or center plane 8. The cell-like recess 5 is now designed so that the flat material from the central surface 8 in a single direction to form a cell recess 10 is arcuate. This recess 10 has a width 6 and a height 13. Its tangent forms the central surface 8 a relatively shallow angle α, so that the recess 10 can be relatively easily compressed upon exertion of pressure on them.

On the other hand, if the shape according to the invention is compared Fig. 3c (Where the flat material also has an upper and a lower main surface 7, 9) with the in the Symmetrieschnitt expedient parabolic recess 10, it can be seen that the cell 5 has a relation to the central surface 8 outgoing raised cell bending edge 14 (plus the proportionate material thickness 12), which has a height (11) at the maximum in the middle of the diagonal webs. Due to the longer training of the cell 5 and its recess 10 bounding wall results here one (compared to the Fig. 3b ) Steeper tangent that extends at an angle β to the central surface 8, and therefore also causes a greater resistance to pressure.

The production of a localized deformation structure can be done in any way, even by that from the DE-A1-197 50 576 Known rolling process, but for their production, the rollers must be separated again and again from each other. Moreover, because of the resulting sheet curvature, then a straightening process is required for straightening, with some of the stiffness gain being lost again. Furthermore, the rolling process limits a regularly paraboloidal buckling formation, which is advantageous for the purposes of this invention.

Exemplary of a pressing operation advantageously used according to the invention is a C-press frame 21 in FIG Fig. 4 represented, with which the deformation structure according to the invention can be pressed in flat materials. This press has a base 25 on which a structural tool 24 is fixed in a known manner. About the structural tool 24 is a plate 23 of resilient, suitably elastic material of certain hardness, lowered onto the structural tool 24 to press the inserted between the tool and the plate 23 flat material with the main surface 9 against the structural tool 24. The elastomer plate 23 is held by a pressure plate carrier 22 on the C-frame 21 and acts on the main surface. 7

The interaction of the structural tool 24 with a resilient plate 23, instead of a rigid counter-tool, causes the intervening sheet metal blank at the vertex points of the raised, preferably arcuate Zellbiegeränder 14 (overbends) contact with the yielding, when moving these two mold halves 23, 24 For example, from an elastomer plate 23 gets. Due to the surface pressure initiated there and the resulting friction, the material of the sheet is held in the edge region of a cell to be generated at these vertexes and initially concaves on these "overbows".

As the tool halves continue to move together, pressure also increases in the center region of the cell due to the resilience of the elastomer plate 23. The result is that upon reaching a certain pressure of the plate 23 (generated by the further collapse of the tool holder), the bump-like cell from the concave state (due to the concern of the sheet at the overbends) jumps more or less spontaneously in the convex state. A further increase in pressure then only leads to the final shaping of the cell. The achievable depth of heeling depends on the thickness of the sheet and its strength properties.

In addition to simple (with an acting punch) acting presses, the method can also be applied in multi-acting pressing systems. By way of example, deep-drawing and stretch-drawing tool systems may be mentioned in which the structuring tool is integrated so that, in addition to the main shaping of the sheet, complete or partial structuring in the form according to the invention can be integrated. Fig. 5 illustrates such a deep drawing process, in which deep-drawn and structured in the same operation. Shown is a pressure plate 23 which is fixed in a die 26. In the main shaping can be done so the pulling of the component. Position 3 shows the drawing bowl and position 2 the drawing flange.

It illustrates Fig. 6 in that the individual plates 23 and structural tools 24 do not always have to be completely flat, but that even slightly curved flat materials can be provided with structuring in the manner shown. Under certain circumstances, however, the structuring tool can not be constructed from modular individual elements. Such a curved structure can not be produced by the roll patterning method.

Based on Fig. 7a to 7d Let the corner region of the structure tool 24 be illustrated. On a base plate 20 of the structural tool 24, the hexagonal shape after Fig. 1 a resulting, individual modules attached, for example, screwed so that the modules are replaceable, if required by wear or as a result of a transformation of the deformation structure. These individual modules comprise once such modules 17, which form the arcuate elevations of the edge zones of the bulge pattern, and those modules 18, which form the not exaggerated edge zones of the bulge pattern. But it is also possible to dispense with the individual modules and provide modules that include a whole Beulzelle. In addition, the entire structural shape field can be worked out of the full tool material. All modules are advantageously using clamping plates (in plan view below) via mounting holes 19 attached to the tool base plate 20. In the top view above, this clamping plate has been omitted for illustration.

It is understood that numerous modifications are possible in the context of the invention with regard to the shape of the modules or with respect to their arrangement, be it in terms of the shape of the cells or their arrangement.

For example, it is favorable, the higher Beulbiegeränder the tool 17 with a outward or from the related to the material to be deformed material 8 facing away sheet provide (which reduces the required pressing forces), as particularly the FIGS. 7 show, but also any other shape could be selected, for example, a double bow od. Like. Generally, the arches of the Beulränder can also be directed inward, that is approximately concave, but this is not preferable. Bows may also be provided at the lower bowing edges of the tool 18, as long as their upper edge does not extend beyond the major surface 7, relative to the material being deformed. Such sheets may preferably be concave. Likewise, it would be conceivable to let the top edge ("top" relative to the representation in the figures) run obliquely to the center plane 8.

Also, the cell well 10 ( Fig. 3c ) have a flattening or upward-pointing indentation (counterbump). Likewise, the method of which a preferred embodiment has been described may be modified in a variety of ways. Thus, the position of the plates 23, 24 can be exchanged, so that approximately the plate 24 is at the top. In place of the elastomeric plate 23 - which is preferred - a non-compliant die plate with negative engraving to the plate 24 may be used, but this is generally not cost effective.

It has also already been mentioned that various flat materials are suitable for the structuring according to the invention, in addition to sheets, natural and synthetic materials, papers and boards, it is also possible to structure composite materials and materials composed of different material types and thicknesses. Successful tests with thin sheets have already been carried out.

In addition to the stiffening effect of the mold structure according to the invention, components provided with this mold structure can be further deformed by utilizing the special geometry shape, which can further increase the stiffening effect.

A particular variant of the invention may consist in introducing into a component by the mold structure according to the invention verses initiating sites, for example to allow a component to buckle at a certain load, e.g. in order to allow energy absorption in the event of a strong pulse-like load.

Another special feature of the invention may be that a component after the main shaping, even after assembly, with appropriate tools (also pliers) can be provided with the inventive mold structure.

Claims (10)

1. A component (1) made of a flat material, having a central surface (8) disposed between two main surfaces (7, 9) extending in parallel to each other, wherein the flat material is provided with a deforming structure (4) which, in part, extends in the form of a compression vertically to the central surface (8), wherein,

   a) at least a partial area (5) of the flat material is provided with the deforming structure (4), and

   b) the deforming structure (4) consists of a grid of adjacent cells (5) that are, preferrably, at least approximately hexagonal as seen from above, wherein the cells are each limited by cell bending edges (14) and (15) that are extending transversely in relation to the central surface (8), characterised in that

   c) a cell (5) that is limited by relatively higher (14) and lower cell bending edges (15) has a central recess (10) extending up to the height (13) below the main surface (9) whereas the higher cell bending edges (14) are formed up to a height (11) above the central surface (8) and the lower cell bending edges (15) are, in essence, formed up to the height of a main surface (7).
2. The component according to Claim 1,
   characterised in that
   the higher cell bending edges meet at least one of the following requirements:

   (a) when a grid of cells (5) that are disposed adjacent to each other is formed, the higher cell bending edges (14) extend along a line that is preferrably continuous (16) (Fig. 1 a);

   (b) the higher cell bending edges (14) are, at least in part, provided with an arched curvature that faces away from the central surface (8) as seen a in lateral view or, rather, in a cross-sectional view.
3. The component according to any one of the preceding claims,
   characterised in that
   the recesses (10) are, at least in a partial area of the cells (5), formed as concave bulges that are, for example, parabolic as seen in a cross-sectional view.
4. A method for the production of a component according to any one of the preceding claims, wherein a deforming structure (4) having the form of cell-type recesses (10) that are limited by cell bending edges (14, 15) are inserted into a flat material by means of deforming dies (24, Figs. 5, 6 and 7), said flat material being limited by main surfaces (7, 9) extending in parallel to each other and having the thickness (12),
   characterised in that
   the cells (5) that are limited by relatively higher (14) and lower cell bending edges (5) have central recesses (10) extending up to the height (13) below the surface (9) whereas the higher cell bending edges (14) are formed up to the height (11) above the central surface (8) and the lower cell bending edges (15) are, in essence, formed up to the height of a main surface (7) and that the recesses (10) as well as the cell bending edges (14, 15) are, in essence, formed at the same time.
5. The method for the production of a component according to any one of the preceding claims,
   characterised in that,
   in relation to the central surface (8), the deforming structure (4) is integrated into a primary forming die that is designed as a pressing, deep-drawing or stretching die, with the result that the secondary formation can, in essence, be achieved in the same process step as the primary formation.
6. The method according to any one of the preceding claims,
   characterised in that
   the deforming structure (4) is only inserted into a partial area of the workpiece and that the deforming dies (24, Figs. 5, 6 and 7) are designed such that a partial area of the deforming structure (4) or only an individual cell (5) is formed.
7. The method according to any one of the preceding claims,
   characterised in that
   the pressing force for generating the cells (5) as well as for the elevation of the cell bending edges (14, 15) is applied to the component (1) across at least one resilient, more particularly elastic surface (23) and that, preferrably, the deforming dies (24, Figs. 5, 6 and 7) are fixed in position on a die carrier that is, in essence, formed like a plate, e.g., flat (Fig. 5) but also like a bend (Fig. 6), said die carrier being pressed against a surface (23) in a pressing process, said surface (23) being resilient, disposed opposite the deforming dies and, in essence, formed like a plate.
8. The method according to any one of the preceding claims,
   characterised in that
   the structuring dies (24) are set up on a carrier (20) made of single elements or modules (17, 18).
9. The method according to any one of the preceding claims,
   characterised in that
   the deforming structure (4) according to the invention is produced in a component or flat material using operations successively following each other or in the form of formation fields pressed in a plurality of single operations.
10. The method according to any one of the preceding claims,
    characterised in that
    a component or flat material is further deformed using the deforming structure (4) according to the invention.

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