EP0798062B1 - Element made of foamed metal - Google Patents

Description

The invention relates to a component made of a metallic Foam material according to the preamble of claim 1 or claim 2. The invention further relates to a Process for the final shaping of such a component according to the Preamble of claim 6 and the use of devices for Execution of the procedure.

Metallic foam materials, either a Foamable metal powder and blowing agent Contain layer or which is a foamable metal powder and contain propellant layer containing at least a solid metal sheet as a top layer is provided, between the solid metal sheet and the foamable layer has metallic bonds, are known per se.

DE 41 01 630 A1 shows how a metallic Powder and an addition of a gas-releasing Blowing agent powder, preferably a metal hydride Foam material is formed after mixing exposed to high pressure and high temperature what can be achieved for example by a hot rolling process can, and then cooled, so that a foamable semi-finished product is created.

DE 44 26 627 A1 describes the production of a material with a foamable, made of metal powder and blowing agent existing layer, at least of a solid metallic Cover layer is limited, shown. For Flat composite materials of this type become a connection the different layers by roll cladding proposed, creating a flat layer material arises, which are foamed after its final shaping should.

The presented methods for producing a suitable Foam material still show no way out the materials provided in reproducible Way to form series components.

The invention has for its object metallic Lightweight components for a consistently dimensionally stable series production, especially in vehicle construction, from flat foam materials to create the type mentioned.

The invention provides for solving this problem for various Starting materials Components with the characteristics of Claims 1 or 2 before and a manufacturing process according to Claim 6 and the use of devices according to the claims 10 and 11 for performing the manufacturing process.

The component according to the invention solves all essential geometric Requirements in body and vehicle construction be placed on flat metallic components. Through the Formation of the transition angle between 100 ° and less than 180 ° is achieved that the structure of the foamed Layer in the area of the transitions not interrupted, drawn in or is diluted, so that the mechanical stability and dimensional accuracy of the component over its entire Area is preserved.

A component according to the invention has a very low mass on, at the same time high rigidity, in particular in the case of multi-layer composites, so that such Components both in the load-bearing area of the body and can also be used for cladding and shielding purposes can.

Components made solely from a metal powder and blowing agent comprehensive foamed porous layer exist, so-called. Integral foam, especially as crash elements be used, with the cellular structure the foamed material has a very good energy absorption capacity results in deformation of the component. It is through the inventive design of the component possible to deform it so far before foaming, that it, for example, as the inner layer of a bumper e.g. B. plastic can be used.

Components that comprise a foamed metallic layer, the one side with a solid metallic top layer provided are suitable, very light and highly rigid Components, for example a vehicle roof, without a stiffening substructure needs to be formed.

Materials that have a foamed layer and a bilateral Have plating with a solid metal sheet, are suitable for the production of components that on both sides a smooth wall and tensile and compressive forces have receiving surface, for example for the rear transverse wall of a vehicle. The foamed location takes over the function of the spacer and the Transfer of thrust. Such a component has also has a high rigidity with a low mass suitable for absorbing high energies - for example in the event of an accident and is also good soundproofing.

The foamed layer usually consists of one Aluminum-based metal powder with added proportions - for example of silicon. By a suitable choice of Alloy elements and parts are mechanical properties of the component adjustable. Also for solid metallic ones Sheet metal offers the use of light metal alloys on.

Fig. 1

in schematischer Ansicht schräg von oben eine Tiefziehform mit aufgelegtem zu verformendem Schaumwerkstoff,

Fig. 2

ein in eine Aufschäumform eingelegtes und einseitig endkonturiertes Formhalbzeug in schematischer perspektivischer Ansicht,

Fig. 3

eine ähnliche Ansicht des Bauteils am Ende des Aufschäumprozesses,

Fig. 4

das gesamte Herstellungsverfahren eines erfindungsgemäßen Bauteil im schematischen Überblick,

Fig. 5

das erfindungsgemäße Aufschäumen des Bauteils in einem schematischen Ablaufplan.

Further advantages result from the drawing and the following description of the component and its manufacturing process. The drawing shows:

Fig. 1

in a schematic view obliquely from above, a deep-drawing mold with a foam material to be deformed,

Fig. 2

a semi-finished molded product inserted into a foaming mold and contoured on one end, in a schematic perspective view,

Fig. 3

a similar view of the component at the end of the foaming process,

Fig. 4

the entire manufacturing process of a component according to the invention in a schematic overview,

Fig. 5

the foaming of the component according to the invention in a schematic flow chart.

A component 1 according to the invention has a foamed one Layer 2, which comprises a metal powder and a blowing agent, which are homogeneous with each other through a mixing process were mixed and then under pressure, for example by axial pressing or by extrusion compact, foamable semi-finished product 2 '' compacted and has been solidified.

In the exemplary embodiment shown is the foamed one Layer 2 on the top and bottom with a solid metallic layer Sheet 3, 4 provided, but this is not mandatory is and in particular when forming an inventive Component 1 is dispensable as a crash element. It is still possible, a foamed layer 2 with only one solid metal cover layer 3 or 4 to connect or groups of several different foamed Layers, possibly separated by solid metallic ones Layers, for example, around impact elements to create, depending on the impact speed and thus -energy a different number of foamed Layers on the deformation caused by the impact participates.

In the embodiment, a double-sided with solid metallic Sheet 3 and 4 provided with foamed layer 2 is the connection between the one at the end of the procedure foamed layer 2 and the solid metal sheets 3 and 4 came about under pressure, that a metallic bond between each Layers 2 ', 3', 4 'before forming and foaming has been achieved. For this purpose, roll cladding is an option a composite of the foamable semi-finished product 2 ", that emerged after the extrusion or axial pressing and the solid metal sheets 3 '', 4 '' between make two rollers 5 so that a composite material 6th with sandwich structure of two solid metallic cover layers 3 'and 4' and a not yet foamed porous Intermediate layer 2 'is formed.

Such an essentially flat metallic composite material 6, which in any case is still a foamable Layer 2 'comprises points between the metallic sheets 3 'and 4' and the foamable layer 2 'metallic Bindings and is now available for further processing to disposal. This flat composite material 6 is initially cut into pieces of suitable size, for example with the help of a saw.

Such a one tailored to the desired external dimensions Composite material 6 now becomes a semi-finished product 7 reshaped, reshaping both continuous Curvature of the composite material 6 can cause as well the expression of individual areas 7 '.

In any case, it points to the deformation of the composite material 6 used for the semi-finished product 7 form 8 transverse to Contact surface of the composite material 6 angles γ in one Size between about 100 ° and 260 °, with rounded edges are so that the composite material can be folded directly 6 to avoid. This also keeps the network obtained in the angular ranges, and the mechanical strength of the semi-finished product achieved by the forming 7 has no isolated weak points.

The shaping can be carried out using known customary shaping measures take place, for example by deep drawing with and without hold-down devices, as is known in body construction, or by a one-sided Forming processes, such as the fluid cell process.

In any case, a semi-finished product 7 is obtained, either contains plane or curved surface areas 7 '' and possibly from this shaped contours 7 'and that for further processing comprises a foamable layer 2 '.

The foaming of the semi-finished product 7 into a component 1 in a defined, reproducible and true to size to design is the real intention of the invention, because this enables components for series production to provide.

For this purpose, the semi-finished product 7 is placed in a foaming mold 9, one wall 12 of which is a side 10 of the semi-finished product 7 is supported extensively, so that this side 10 must already have its final contour, because a further contouring by foaming the semi-finished product 7 to a component 1 no deformation of this Page 10 brings more with it.

The walls 12, 13 of the foaming mold 9 can, for example made of steel or ceramic. In each It is important that the component 1 despite its foaming prevailing internal pressure no connection with the Walls 12, 13 of the foaming mold 9 are received. Anything here To prevent them from sticking together, these walls 12,13 may be coated.

Through the extensive support of a final contour Page 10, i.e. along one side of the surface extension, of the not yet foamed semi-finished product 7 is avoided when foaming that this is already the End contour of the later component 1 side 10 during foaming by the pressure of the gas-releasing Blowing agent in the foaming layer 2 'to the outside is deformed. It is beneficial and for some Applications mandatory, the opposite side 11 of the Semi-finished product 7 a further wall 13 of the foaming mold 9 to assign that with a fixed distance to the wall 12 is arranged to thereby measure the extent of expansion of the foaming Layer 2 'defines and thus limit a dimensional accuracy of the finished component 1 with less than Allow 5/10 mm deviation. With an adjustability the distance between the walls 12 and 13, the Preselect the thickness of component 1 - and thus also its Density and its mechanical strength. This means that the same starting material for components 1 with completely different properties can be used. The larger the allowed foaming path in the foaming mold 9 is left, the lower the density of the finished Component 1. Its rigidity can also be reduced to this Set way. For example, the different Stiffness requirements of a short Car roof or a long roof of a station wagon over the Degree of foaming can be met.

The upper wall 13 of the foaming mold can be omitted if the dimensional accuracy of the foaming semi-finished product 7 low demands are made, such as for example in the formation of crash elements.

In most cases, however, it will be essential through both walls 12 and 13 the frothing path and thus to limit the final dimension of the foamed component 1, whereby a series production of the same foamed Components 1 is enabled.

The two opposite walls 12 and 13 of the foaming mold 9 have essentially parallel surface structures on, since it is not possible by foaming further structures, for example, only in one surface 11 to emboss the semi-finished product 7 - for example through recesses in the delimiting wall 13 of the foam mold 10.

By means of such a defined foaming, components 1 received as lightweight series products, for example as body panels, as bulkheads or partitions towards the engine or trunk or for crash protection and stiffening function within the body can be used.

Such components can be curved overall, for example for use as outer door panels or from plane levels or curved areas 1 '' worked out pronounced Include contours 1 'in the area of the transitions compared to the curved or flat surface area Angle α in the order of magnitude between 100 ° and less than Have 180 °, so that hereby the most diverse requirements on body panels or body panels can be fulfilled - with very light and torsion-resistant Components 1.

Likewise, 1 'angles can be formed within the pronounced contours β occur in the same order of magnitude, so that also maximum flexibility and adaptability the demands of the body builder is given.

With the method presented here and the resulting For the first time, components can be made from materials metallic foams - and possibly solid metallic ones Sheets connected to them - for series production use and in a reproducible way known forming processes and a subsequent defined one Foaming of the metal powder and blowing agent Layer 2 'the advantages that such a lightweight construction offers, put into practice.

Claims (11)

1. A component, for in particular agricultural vehicles, preferably a body work component for motor vehicles, consisting of a foamed metallic material with a foamed porous layer comprising powdered metal and propellant, characterised in that the component (1) has at least one contour (1') stamped out of its surface (1"), whereby the angles α occurring in the areas of the transitions between the three-dimensionally embossed contour (1') and the surface area (1") are kept to a magnitude between 100° and < 180°.
2. A component, for in particular agricultural vehicles, preferably a body work component for motor vehicles, consisting of a foamed metallic material with at least one foamed porous layer comprising powdered metal and propellant and at least one solid metal plate, whereby metallic bonds exist between the solid metal plate and the foamed porous layer, characterised in that the component (1) has at least one contour (1') which is embossed out of its surface (1"), whereby the angles α occurring in the area of the transitions between the three-dimensionally formed contour (1') and the area of the surface (1") are maintained to a magnitude between 100° and < 180°.
3. A component according to claim 1 or 2, with a raised embossed contour, within which angles arise, characterised in that these angles (β) are maintained within the range from 100° to < 180°.
4. A component according to one of claims 1 to 3, characterised in that the surface areas (1") are plane.
5. A component according to one of claims 1 to 3, characterised in that the surface areas (1") are curved.
6. A method for final shaping of a component formed from substantially flat foamed metallic material, in accordance with one or more of claims 1 to 3, which at least one layer comprising powdered metal mixed with a propellant and possibly connected to at least one solid metal plate by for instance rolling-plating, whereby the layers adhere to one another with a metallic bond after the application of pressure and whereby the flat foamed material is, by unilateral or bilateral shaping, reshaped into a shaped semi-finished product which is finally contoured at least along one side of its surface, characterised in that the resulting semi-finished shaped product (7) is placed into a foaming mould (9) which has one wall (12) adapted to its finally contoured side (10), and is foamed therein.
7. A method according to claim 6, characterised in that by an adaptation of the walls (12, 13) of the foaming mould to both sides (10, 11) of the semi-finished shaped product (7), the amount of expansion of the layer (2') to be foamed is limited and defined by the walls (12, 13) of the foaming mould (9).
8. A method according to one of claims 6 to 7, characterised in that as a result of the reshaping of the composite material (6), a curvature of surface areas (7") is created in a semi-finished shaped product (7).
9. A method according to one of claims 6 to 8, characterised in that an embossing of partial areas (7') of surface areas (7") of the semi-finished shaped product (7) is brought about by the reshaping of the composite material (6).
10. Use of an apparatus comprising a mould (8) which on one side supports a flat composite material (6) resting on it and which has crosswise to its supporting surface angles (γ) of a magnitude between 100° and 260° for carrying out the method according to one of claims 6 to 9.
11. Use of an apparatus in which, for carrying out the method according to claim 6, oppositely disposed walls (12, 13) of a foaming mould (9) have substantially parallel surface structures.

Images