WO2024022961A1

WO2024022961A1 - Underbody cladding element, motor vehicle body shell and method for producing an underbody cladding element

Info

Publication number: WO2024022961A1
Application number: PCT/EP2023/070248
Authority: WO
Inventors: Maximilian Heinrich; Jürgen Schmidt; Viktor DEMMER; Ingo Fliege
Original assignee: Audi Ag; Volkswagen Ag
Priority date: 2022-07-25
Filing date: 2023-07-21
Publication date: 2024-02-01
Also published as: DE102022118581B3

Abstract

The invention relates to an underbody cladding element (5) for a motor vehicle, more particularly an electric motor vehicle, wherein the underbody cladding element (5) comprises a main body (8) which is made of at least one base material and is at least substantially flat, wherein the underbody cladding element (5), integrated in the main body (8), comprises at least one prefabricated structure element (9) which consists of a ductile and stiffening reinforcement material and which at least substantially completely passes through the main body (8) in at least one structure direction (10).

Description

Underbody cladding element, motor vehicle bodyshell and method for producing an underbody cladding element

DESCRIPTION:

The invention relates to an underbody cladding element, in particular a rear underbody cladding element, for a motor vehicle, in particular an electric motor vehicle, wherein the underbody cladding element comprises an at least essentially plate-like base body formed from at least one base material. In addition, the invention relates to a motor vehicle bodyshell and a method for producing an underbody cladding element.

In motor vehicle technology, especially in passenger cars, it is known to provide motor vehicles with underrun protection that is as fully covered as possible, which can also be referred to as underbody cladding. Such an underbody cladding can, for example, consist of several underbody cladding elements, which can be connected to one another and/or to the body of the motor vehicle in the bodyshell. Underbody panels have a variety of beneficial properties.

The use of underbody panels makes it possible to protect motor vehicle components in “wet areas” from dirt or grime, weather influences and damage caused by the impact of motor vehicles. For example, dirt and grime may include thrown stones, sand, and the like, while weather influences include ice, snow, rain, and the like. A fully lined underbody of a motor vehicle also results in aerodynamic advantages. The air below the motor vehicle can be guided in a much more streamlined manner, so that the motor vehicles can aerodynamically implement more lift or downforce on the rear axle. This is particularly out View of the driving dynamics when cornering sporty motor vehicles due to increased contact pressure or as a measure to relieve the rear of the motor vehicle at high speeds, since in the latter case there is less friction and therefore less rolling resistance. An aerodynamically optimized motor vehicle also has lower energy consumption, especially fuel consumption, due to the lower flow resistance.

It has also been proposed to use underbody panels acoustically to attenuate road noise caused by the movement of the motor vehicle. In this way, occupants in the interior of the motor vehicle can enjoy greater acoustic comfort because less noise pollution from the surroundings is perceived. With regard to the acoustically dampening effect, suitable materials can be used for the underbody cladding elements, and additional acoustic elements can be attached to the underbody cladding, for example glued or clipped on.

Fully clad underbody panels are often used, especially in fully electrically powered motor vehicles (electric vehicles or BEVs - Battery Electric Vehicle), as the range advantages resulting from lower energy consumption outweigh the costs of implementing underbody cladding elements. Particularly when it comes to electric vehicles, being able to offer long ranges is extremely relevant for competitiveness.

Solutions known in the prior art for realizing underbody cladding often only cover part of the possible advantages. For example, underbody panels made of plastic have been proposed, in which good aerodynamic properties are used and on which an acoustic mat can be applied as a dampening acoustic element. Underbody cladding made of a textile material has also already been proposed, in which a combination of the acoustic effect, i.e. acoustic insulation, with holistic closure of the underbody (aerodynamic effect for lower consumption) can be realized. With such designs, however, there is a risk of the underbody paneling “sagging” if water or snow gets in while driving. A variety of attachment points are used here to counteract this.

There are types of motor vehicles in which there are increased requirements for bending and torsional rigidity that cannot always be implemented via the vehicle structure, in particular the body, so that underbody panels with improved properties in this regard have also been proposed. Such types of motor vehicles include, for example, vehicles with a long wheelbase and/or long rear overhangs (for example LWB vehicles - “Long Wheel Base” vehicles). It was suggested here to provide additional struts on the rear vehicle, which, however, no longer allow underbody paneling for reasons of installation space and make assembly more difficult.

In extreme cases, it has been proposed to use underbody panels made of metallic materials, but this results in an extremely high weight of the underbody paneling elements in order to achieve the necessary rigidity, especially in the rear vehicle. In addition, such underbody cladding does not have any useful acoustic properties.

Another type of vehicle that has special requirements for rear vehicle rigidity are convertibles, as they lack the roof system and the B-pillar. It was also proposed there to provide so-called diagonal struts and/or struts for the subframe, which, however, leads to a further exhaustion of the installation space downwards, so that closure of the underbody is no longer possible, which results in aerodynamic disadvantages. It has already been proposed in the prior art to attach struts for stiffening an underbody cladding element itself to the underbody cladding element, this serving to provide sufficient vertical rigidity of the underbody cladding element even in the event of water entry or snow-ice entry. With this solution there is also the problem that struts or other components can come loose from the fastening and fall to the ground.

DE 10 2016 005 264 A1 relates to a bodyshell of a motor vehicle, which includes a vehicle body and an underrun protection, thus an underbody cladding element. So that a particularly large amount of installation space can be available in the bodyshell for other parts, the underrun protection comprises at least one support area, by means of which at least a portion of the vehicle body can be supported in the event of a traffic accident. The underrun protection is formed as a sandwich panel with fiber composite materials, so that it can absorb and/or support higher forces than, for example, in comparison to an underrun protection made of a sheet metal component. An additional profile element is attached to the side of the sandwich panel, which allows a particularly advantageous introduction of force into the underrun protection in the event of a side impact and at the same time can reduce or even prevent rotation of the side sill. The underrun protection is to be provided in particular below a high-voltage battery of the motor vehicle there.

The additional, lateral profile element is intended to improve the crash behavior, i.e. collision behavior, which is particularly important with regard to, for example, the protection of a high-voltage battery. A maximally rigid push plate should therefore be implemented as underrun protection in order to reduce or counteract collision loads. The disadvantage is that this makes no contribution to the global flexural and torsional rigidity during operation of the motor vehicle and no damping of acoustic or other vibrations is possible. In addition, the positioning of such additional profile elements on the edge only allows a very limited influence on the usual ones Load paths within the motor vehicle and creates problematic fastening points.

DE 10 2019 124 642 A1 relates to a trim component for a motor vehicle and a method for producing it. The cladding component comprises a multi-layer panel component with a folding honeycomb core made from a plastic in a continuous manufacturing process, which is arranged between at least two cover layers. The folding honeycomb core achieves better mechanical properties and better structural rigidity with a particularly low weight, and the cladding component should also be particularly economical to produce. A load-bearing design of intermediate layers is also conceivable. However, here too there is the problem that there are no advantages in terms of overall vehicle rigidity.

DE 10 2015 203 852 A1 relates to a plastic component and a method for producing it. The plastic component has a base body made of LWRT plastic and an injection molding material that is connected to the base body. The injection molding material is arranged in at least one area of force introduction of the plastic component, in which the plastic component is loaded in a used state. During production, the base body is manufactured in such a way that local cavities are created into which the injection molding material can be injected. In order to create the cavities (“lofting”), heating is provided so that the injection molding material can only fill small cross-sections. In this respect, the loads that can be absorbed in the injection molding are limited, so that in particular no contribution to the rigidity of the entire vehicle can be made. Furthermore, a complex injection molding process is necessary to implement the solution there.

The invention is based on the object of specifying an underbody cladding element which contributes to both the bending and torsional rigidity of the desired can contribute to the entire motor vehicle and can at least partially dampen vibrations that occur, especially with extended rears and long wheelbases.

To solve this problem, in an underbody cladding element of the type mentioned at the outset, it is provided according to the invention that the underbody cladding element, integrated into the base body, comprises at least one prefabricated structural element consisting of a ductile and stiffening reinforcing material, which at least essentially completely runs through the base body in at least one structural direction.

According to the invention, it is therefore proposed to integrate a prefabricated structural element, i.e. a semi-finished product, as a type of “insert” into the base body of the underbody cladding element, so that it forms a type of “load-bearing core”. On the one hand, the structural element has a high level of rigidity and extends in at least one structural direction at least essentially over the entire length of the base body and is therefore able to make a significant contribution to the torsional and bending rigidity of the entire motor vehicle. The at least essentially complete passage is to be understood as meaning that the structural element runs at least between the edge-side connection points, where the underbody cladding element is attached to other components of the motor vehicle bodyshell via fasteners, and can have a load-bearing and load-guiding effect there.

On the other hand, however, a ductile material is used, which makes it possible to dampen vibrations of various types and thus simultaneously act as a damping element. It can therefore be particularly advantageous to provide that the reinforcing material is a metal or a metal alloy, in particular steel, aluminum or titanium. Such metals have great stability and rigidity at the same time ductility, especially in the range of an elongation at break of 10% or more. In general it can be said that the reinforcing material can preferably have an elongation at break of more than 8%. This design ultimately makes it possible to achieve property optimization through functional integration, in particular with regard to acoustic damping, for which embodiments of the present invention can also provide that the at least one base material comprises a noise-damping material. Then the property optimization not only refers to an increase in the overall rigidity of the motor vehicle, especially outside of singular extreme load cases such as crashes in normal operation, and simultaneous vibration damping, but also to acoustic damping.

Overall, it can be said that prefabricated, i.e. finished, structural elements, such as profiles, lattice structures and/or panels, are used as inserts and these are introduced into the underbody cladding element as a kind of core, so that a significant positive contribution to the global bending and torsional capacity of the motor vehicle is achieved during operation, but at the same time ductility is provided so that the structural elements can be used as damping elements to reduce vibrations in the motor vehicle. By using prefabricated structural elements, the solution according to the invention is less cost-intensive and simpler and quicker to produce. The underbody cladding element can be designed to ideally fit the installation space, but with simultaneous freedom of load distribution through appropriate choice of structural elements and their positioning and orientation.

In this context, in a particularly advantageous embodiment of the present invention, it can also be provided that at least one structural direction is a diagonal direction with respect to the longitudinal axis of the motor vehicle in the installed state. Studies have shown that loads, especially in the rear of the vehicle, often have to be guided in precisely such oblique directions, so that the present invention allows appropriate force transmission and guidance. For example, load-bearing and load-guiding diagonal struts, as previously used instead of an underbody paneling element in the rear vehicle, can be used, for example Convertibles can now be integrated into the underbody paneling element and still do their job there. Within the base body, load absorption/load guidance in any load path can be made possible, especially in oblique load paths.

Of course, it is also conceivable that at least one structural direction includes a longitudinal direction and/or a transverse direction with respect to the longitudinal axis of the motor vehicle in the installed state. With particular advantage in this context, at least two structural directions each covered by at least one of the at least one structural element can be provided, which means that a structural element can pass through the entire base body in one or more structural directions, although it is alternatively also possible to have separate structural elements for different structural directions to provide, for example, two structural elements that run towards one another in different oblique directions and are provided symmetrically with respect to the longitudinal axis of the motor vehicle in the installed state, in order to guide loads that lie more laterally on load paths centrally to the rear with particular advantage.

In other words, the load-bearing structural elements that define corresponding load paths can be arranged in a wide variety of ways depending on the application, in particular longitudinally and/or transversely and/or angled, with flat or high configurations also being possible.

It should be generally noted at this point that it is particularly advantageous to use fasteners to connect the underbody cladding element to the rest of the shell, which at least partially engage directly on the structural elements, and therefore fasten them as directly as possible, for example by using appropriate screws and / or bolts are guided through through holes in the structural elements. In other words, the at least one structural element can provide at least one through opening for fastening means at a fastening position Have attachment to the bodyshell, which will be discussed in more detail with regard to the motor vehicle bodyshell according to the invention.

In addition to an already extremely simple installation of the underbody cladding element according to the invention, since only one part can be handled, a simple connection concept can also be achieved, especially in the rear vehicle. This comes with the advantage of the load-carrying or load-bearing design in the sense of a significant increase in rigidity for the entire vehicle during operation, which also brings with it a high level of robustness against water entry and snow entry. In particular, no additional connection points or fastening points are necessary in the inner area of the at least essentially plate-shaped base body, since a connection to the remaining shell in the edge area, in particular via appropriate fastening means, is completely sufficient. While this connection in the edge area results in an increase in the bending and torsional rigidity for the entire motor vehicle, i.e. an improvement in global properties, an increase in rigidity is of course also achieved locally only for the underbody paneling element itself, so that this can also be achieved when subjected to water and/or or snow/ice entry has sufficient robustness and stability.

It can generally be said that the underbody cladding element, particularly when used in the rear vehicle, can have a fundamentally rectangular basic shape with recesses on both sides for wheels and/or axle components. Axle components could include, for example, wishbones, spring steering, damper mounts or the like.

The underbody cladding element according to the invention is in particular a rear underbody cladding element, which is therefore to be arranged on the underside of the rear vehicle. In the area of the rear of motor vehicles with a longer rear and/or a long wheelbase, oscillations and vibrations often occur at the rear, which are absorbed by the structural elements due to their ductility be steamed. In addition, in other vehicle types, such as convertibles, there are losses in rigidity, especially in the area of the rear vehicle, which can be advantageously compensated for by the underbody cladding element.

Especially in the rear vehicle area, for example in convertibles, sports cars, LWB vehicles and the like, where unwanted oscillations and/or vibrations can occur, a vibration-damping effect is present due to the ductility of the reinforcing material, in particular metal. In addition to these massive advantages, there are also the fundamental advantages of underbody cladding, namely improved aerodynamics and protection from objects, road surfaces, dirt, weather influences and the like, some of which have not been possible to date.

Specifically, it can be provided that at least one of the at least one structural element is a rod and/or a profile element, in particular an extruded profile, and/or a shear plate and/or a shear panel and/or a grid element. With regard to the shape and form of the structural element, the present invention also offers a high degree of flexibility due to the integration of a prefabricated part, i.e. semi-finished product, into the base body in order to implement the desired load paths within the underbody cladding element. While rods and/or plates, which can also be understood as solid profiles, are easy to produce and have a high level of stability, hollow profiles, for example extruded profiles, can possibly bring about further advantages with reduced weight. Grid-like structural elements have the advantage of defining load paths in two mutually perpendicular directions, for example in a longitudinal direction and a transverse direction as structural directions. The use of individual rods or rod-like profile elements offers the advantage of varying the structural direction, for example along the transverse direction, for example to provide a rod centrally in the longitudinal direction, on which one or more rods or rod-like hollow profiles are attached laterally in oblique directions (diagonal directions). Connect structural directions, i.e. with an angle against the longitudinal direction, in order to act as diagonal struts or oblique struts.

Since the underbody cladding element according to the invention is intended to advantageously improve the overall rigidity of the motor vehicle, in particular during normal operation of the motor vehicle, the at least one structural element can certainly form a larger proportion of the underbody cladding element. It can thus be provided that the at least one structural element comprises more than 20% of the total weight and/or total volume.

The structural element is integrated into the base body, and is therefore surrounded by the base body at least on the top and bottom, in particular on all sides, and in particular is also held by it. This enables increased stability, robustness and significantly improved handling, especially with regard to structural elements that may come loose.

There are also a number of options for the specific design of the base body within the scope of the present invention, wherein the base body can preferably have a sandwich structure, with the at least one structural element being arranged between two outer layers, in particular pressed or cast between them.

With particular advantage, the at least one base material can comprise an LWRT material. LWRT stands for “Low Weight Reinforced Thermoplastic” and describes materials that can, for example, be based on a nonwoven material and can be formed by a mixture of glass fibers and thermoplastic fibers, for example polypropylene or polyester. In particular, LWRT materials offer high rigidity and low weight. LWRT materials can be provided in multiple layers to provide desired properties, which may also relate to acoustic attenuation. This means that using LWRT materials can also achieve acoustic damping, particularly towards the interior of the motor vehicle. LWRT materials have a specific processing temperature, so that it is conceivable, for example, to position the structural element between at least one layer of the LWRT material, to heat the LWRT material to the processing temperature and to press the underbody cladding element, specifically the base body, or a to obtain other appropriate technology. The same procedure can be applied to other textile materials. Acoustic effectiveness, specifically a noise-damping effect, can also be achieved for other textile materials with which a sandwich construction can be realized. Textile materials, in particular LWRT materials, therefore represent examples of noise-absorbing base materials. By using the particularly preferred LWRT material, a particularly preferred embodiment is achieved, because the additional properties of low weight and high acoustic effectiveness with regard to noise attenuation represent additional, often desired advantageous properties.

However, particularly in the high-performance sector, it can also be expedient to use fiber composite materials, for example CFRP layer components, which have the load-bearing structural elements as their core. This is particularly advantageous for use in racing or sports cars. For production, it can also be provided here that the at least one structural element is first placed between at least one layer of a corresponding fiber material, whereby the base body can be produced by adding, for example casting, with a matrix material, in particular resin.

In a particularly simple and cost-effective variant, it can also be provided that the at least one base material comprises a plastic with which the at least one structural element is encapsulated. In principle, known plastics can be used here. In addition to the underbody cladding element, the present invention also relates to a motor vehicle bodyshell, comprising a body and at least one underbody cladding element of the type according to the invention. All statements regarding the underbody cladding element can be transferred analogously to the motor vehicle bodyshell, with which the advantages already mentioned can also be obtained.

In this context, it can be particularly advantageously provided that the underbody cladding element is fastened via fastening means to at least one component of the body and/or a battery carrier, in particular an underrun protection, for a high-voltage battery of the motor vehicle and/or at least one further underbody cladding element, the fastening means being on the underbody cladding element side at least partially attach to at least one of the at least one structural element. In the case of a rear underbody paneling element, in an electric motor vehicle this can, for example, be connected to the rear of a battery carrier or an underrun protection for a high-voltage battery, which is usually provided centrally in the motor vehicle. The rear underbody paneling element can then be attached via the fastening means, for example, to a vehicle frame and/or sills and/or a spare wheel well and/or a storage compartment under the loading floor and/or to a body side member and/or other body components; In addition or as an alternative to attachment to the sills, attachment to the battery carrier can also take place, which preferably forms part of the underbody paneling as underrun protection for the high-voltage battery, and can therefore also be understood as a further underbody paneling element. The battery carrier can also be designed as a battery frame, in particular comprising cross and/or longitudinal members, and/or the attachment can take place via a connecting console.

In the general case, the attachment is basically carried out with, in particular, the edge connection of the at least one structural element to the rest of the shell in order to achieve the desired advantageous properties the bending and torsional rigidity of the entire motor vehicle. Due to the stiffening using the integrated, prefabricated structural elements, (additional) fastening in a central area is not necessary, not even with regard to water and/or snow ice entry.

It can specifically be provided that the fastening means is a bolt fastened to the component and/or the battery carrier and protruding through a through opening in the underbody cladding element with a nut fastening the underbody cladding element and/or a separate holder with a screw connection and/or one in or on the component and/or a threaded clamp attached to the battery carrier and an associated screw fastening the underbody paneling element are provided. Particularly preferred are embodiments in which a bolt protruding from the body component and/or the battery carrier is used, which can be guided through a corresponding through hole in the underbody paneling element, whereupon this can be easily fastened using a nut. In exemplary embodiments, it is conceivable that the bolt is formed directly on the component or the battery carrier. However, it is also possible to attach it to it. The bolt has a suitable thread for the nut. In particular on battery carriers, it is also possible to attach a threaded clamp to it and to attach the underbody cladding element, in particular through a corresponding through opening, by means of a screw. Less preferred is a holder as an additional element, which can be screwed onto the component or the battery carrier and the underbody paneling element.

The vehicle bodyshell can be intended in particular for an electric vehicle (BEV). Additionally or alternatively, the motor vehicle for which the motor vehicle shell is intended may be a convertible and/or a motor vehicle with a long wheelbase and/or a motor vehicle with a particularly long rear. Finally, the invention also relates to a method for producing an underbody cladding element, in particular a rear underbody cladding element, for a motor vehicle, in particular an electric motor vehicle, wherein the underbody cladding element comprises an at least essentially plate-like base body formed from at least one base material. According to the invention, the method has the following steps:

- Providing at least one prefabricated structural element consisting of ductile and stiffening reinforcing material,

- Production of the base body with integration of the structural element in such a way that the structural element passes at least essentially completely through the base body in at least one structural direction.

It also applies to the method that all statements regarding the underbody cladding element according to the invention as well as the motor vehicle bodyshell continue to apply, so that the corresponding advantages can also be obtained here. In particular, the reinforcing material can be a metal or a metal alloy.

According to the variants already mentioned (textile material, fiber composite material or plastic), the base body can be manufactured in different ways. In a first variant, it can be provided that when using a textile material and/or an LWRT material as the base material, the structural element is placed between each layer of the textile material and/or LWRT material and the base body is produced by pressing. When using a fiber composite material as the base material, it can be provided that the structural element is placed between at least one layer of a fiber material, whereupon the base body is produced by casting with resin. In the third variant, it can finally be provided that when using a plastic as the base material, the structural element is encapsulated with the plastic to produce the base body. Further advantages and details of the present invention emerge from the exemplary embodiments described below and from the drawings. Show:

1 is a schematic diagram of a motor vehicle bodyshell according to the invention,

2 shows a top view of a first exemplary embodiment of a rear underbody paneling element,

3 shows a top view of a second exemplary embodiment of a rear underbody paneling element,

4 shows a top view of a third exemplary embodiment of a rear underbody paneling element,

5 shows a top view of a fourth exemplary embodiment of a rear underbody paneling element,

6 shows a schematic cross-sectional view of an underbody cladding element in a first embodiment,

7 shows a schematic cross-sectional view of an underbody cladding element in a second embodiment,

Fig. 8 shows a first possible embodiment of a fastening means, and

Fig. 9 shows a second possible embodiment of a fastener.

Fig. 1 shows a schematic sketch of a cross section of a motor vehicle bodyshell according to the invention for a motor vehicle, here an electric motor vehicle (BEV). The motor vehicle bodyshell 1 initially comprises a body 2, which may include various body components. To realize an underbody cladding 3, the shell 1 comprises a front underbody cladding element 4 and a rear underbody cladding element 5, which, together with an underbody protection 6 as a battery carrier of a high-voltage battery, of which only the battery housing 7 is shown in FIG. 1, form the completely closed underbody cladding 3. On the side of the underrun protection 6, sill trim elements can also be provided on the sills (not shown). At least the rear underbody cladding element 5 has a base body 8, in which, for the sake of clarity, only one structural element 9 is indicated schematically at one point, which is made of metal or a metal alloy, i.e. a ductile and stiffening reinforcing material. At least in one structural direction, the structural element 9 extends over the entire length or extent of the base body 8 and thus of the underbody cladding element 5. The underbody cladding element 5 is connected to further components of the shell 1 via fastening means not shown here, the fastening means basically being on the at least one Attack structural element 9, thus establishing a firm connection between this and the other component of the shell 1.

The rear underbody cladding element 5 can be connected, for example, to a vehicle frame, the underrun protection 6, the sills and/or other components of the bodyshell 1 via the fastening means.

Fig. 2 shows a schematic top view of a first exemplary embodiment of a rear underbody cladding element 5. Two structural elements 9, which act as diagonal struts, are integrated into the base body 8, marked with dashed lines. In the present case, these cover two structural directions 10 and therefore define load paths in the corresponding structural directions 10. In applications, the oblique or angled course relative to the longitudinal axis 11 of the motor vehicle can correspond to a main load direction. 3 shows a second exemplary embodiment of a rear underbody cladding element 5 according to the invention, in which several structural elements 9 are shown, in this case running in the longitudinal direction as structural direction 10. The two uppermost and the two lowest structural elements 9 are clearly not designed consistently due to the recesses 12 for the rear wheels and axle components.

It should be noted that in general the base body 8 can also be designed like a plate and/or have a rectangular bounding box, but can have side recesses for the rear wheels and axle components.

Fig. 4 shows a third exemplary embodiment of a rear underbody cladding element 5, in which the only structural element 9 there is designed as a grid element, which forms load paths in two mutually perpendicular structural directions 10, namely the longitudinal direction and the transverse direction.

Finally, Fig. 5 shows a fourth exemplary embodiment in which the only structural element 9 is designed as a push plate.

In principle, the structural elements 9 in all of these and other conceivable exemplary embodiments can be designed as solid profiles, in particular rod- or plate-like, or also as hollow profiles. In order to provide a desired, significant improvement in the bending and torsional rigidity of the entire motor vehicle or entire bodyshell, they can also make up more than 20% of the total volume and/or total weight of the underbody cladding element 5.

The structural elements 9 are integrated into the base body 8, which can consist of at least one base material, for example a textile material, a fiber composite material and/or a plastic. Preferred If noise dampening, i.e. acoustic effect, of the underbody cladding element 5 is desired here, textile materials, in particular LWRT materials, which are particularly light. Fiber composite materials such as CFRP are suitable for high-performance applications, and plastics for more cost-effective applications. Depending on the at least one base material used, different construction methods and specific manufacturing processes result, for example in the case of textile materials, in particular LWRT materials and fiber composite materials, a sandwich-like structure is used, in which at least one layer is provided above and at least one layer below the at least one structural element 9 is. In the case of plastics, the structural element 9 is encapsulated.

Fig. 6 shows a schematic cross section through an embodiment in which the structural elements 9, which are presently designed as metallic hollow profiles, are covered on the top and bottom in a sandwich structure by a textile material 13, for example LWRT material 13. The base body 8 can then be produced by pressing.

Fig. 7 shows a schematic cross section through a further embodiment in which a plastic 14 was used to encapsulate the structural elements 9, here by way of example (from left to right) a hollow profile, a solid profile (rod) and a shear field or a shear plate are shown.

8 shows, as an exemplary implementation of the fastening means 15, a connection of the rear underbody paneling element 5 to the underrun protection 6 of the high-voltage battery. A threaded clamp 16 is attached to the underrun protection 6, into which a screw 17 is inserted, which extends through a through opening, which is also provided in at least one of the at least one structural element 9.

A second possible embodiment of the fastening means 15 is in Fig. 9 for connecting the rear underbody paneling element 5 to a Load-bearing point or connection point of the body 2 with sufficient connection rigidity, here a body component shown as an example

18 of the body 2, shown. There is a bolt on the body component 18

19 attached, which in turn extends through a through opening, which is also provided in at least one of the at least one structural element 9. A nut 20 is screwed onto the bolt 19 using a corresponding thread.

Other configurations of the fastening means 15 are also fundamentally conceivable, for example the use of a separate holder, but are less preferred.

Claims

PATENT CLAIMS:

1 . Underbody cladding element (5) for a motor vehicle, in particular an electric motor vehicle, wherein the underbody cladding element (5) comprises an at least essentially plate-like base body (8) formed from at least one base material, characterized in that the underbody cladding element (5) is inserted into the base body (8) integrates at least one prefabricated structural element (9), consisting of a ductile and stiffening reinforcing material, which comprises the base body (8) in at least one structural direction (10).

2. Underbody cladding element (5) according to claim 1, characterized in that the reinforcing material is a metal or a metal alloy, in particular steel, aluminum or titanium, and / or has an elongation at break of more than 8% and / or that the at least one base material includes noise-insulating material.

3. Underbody cladding element (5) according to claim 1 or 2, characterized in that at least one structural direction (10) comprises a diagonal direction and / or a longitudinal direction and / or a transverse direction with respect to the longitudinal axis (11) of the motor vehicle in the installed state and / or at least two Structural directions (10) covered by at least one of the at least one structural element (9) are provided.

4. Underbody cladding element (5) according to one of the preceding claims, characterized in that at least one of the at least one structural element (9) is a rod and / or a profile element, in particular an extruded profile, and/or a shear plate and/or a shear panel and/or a grid element and/or the at least one structural element (9) comprises more than 20% of the total weight and/or total volume.

5. Underbody cladding element (5) according to one of the preceding

Claims, characterized in that the structural element (9) is surrounded by the base body (8) at least on the top and bottom, in particular on all sides.

6. Underbody cladding element (5) according to one of the preceding claims, characterized in that the base body (8) has a sandwich structure, the at least one structural element (9) being arranged between two outer layers, in particular pressed or cast between them.

7. Underbody cladding element (5) according to claim 6, characterized in that the at least one base material comprises an LWRT material (13) and / or a textile material (13) and / or a fiber composite material.

8. Underbody cladding element (5) according to one of claims 1 to 5, characterized in that the at least one base material comprises a plastic (14) with which the at least one structural element (9) is encapsulated.

9. Motor vehicle bodyshell (1), comprising a body (2) and at least one underbody cladding element (5) according to one of the preceding claims.

10. Motor vehicle shell (1) according to claim 9, characterized in in that the underbody cladding element (5) is fastened via fastening means (15) to at least one component of the motor vehicle bodyshell (1), in particular a body component and/or a battery carrier (6) for a high-voltage battery of the motor vehicle and/or a further underbody cladding element (4). , wherein the fastening means (15) attach the underbody cladding element side at least partially to at least one of the at least one structural element (9). Motor vehicle bodyshell (1) according to claim 10, characterized in that the fastening means (15) is a bolt (19) fastened to the component and protruding through a through opening in the underbody cladding element (5) with a nut (20) fastening the underbody cladding element (5) and / or a separate holder with a screw connection and/or a threaded clamp (16) fastened in or on the component and an associated screw (17) fastening the underbody paneling element (5) are provided. Method for producing an underbody cladding element (5) for a motor vehicle, in particular an electric motor vehicle, wherein the underbody cladding element (5) comprises an at least essentially plate-like base body (8) formed from at least one base material, characterized by the following steps:

- Providing at least one prefabricated structural element (9) made of ductile and stiffening reinforcing material,

- Production of the base body (8) with integration of the structural element (9) in such a way that the structural element (9) passes at least essentially completely through the base body (8) in at least one structural direction (10). Method according to claim 12, characterized in that when using a textile material (13) and/or an LWRT material (13) as the base material, the structural element (9) is placed between at least one layer of the textile material and/or LWRT material (13) and the base body (8 ) is produced by pressing. Method according to claim 12, characterized in that when using a fiber composite material as the base material, the structural element (9) is placed between at least one layer of a fiber material, whereupon the base body (8) is produced by casting with resin. Method according to claim 12, characterized in that when using a plastic (14) as the base material, the structural element (9) is overmolded with the plastic (14) to produce the base body (8).