Underbody protection for motor vehicles, motor vehicle with underbody protection

Abstract

Underbody protection (1) for a motor vehicle, comprising: - at least one first protective element (10); - a support structure (30) having a plurality of ribs (31); and - at least one second protective element (20), wherein - the support structure (30) is sandwiched between the first protective element (10) and the second protective element (20) and is connected to each of them, - wherein the ribs (31) extend between the first protective element (10) and the second protective element (20), so that a plurality of cavities (2) are formed between the first protective element (10) and the second protective element (20), and - wherein the support structure (30) has a base plate (32) from which the plurality of ribs (31) extend, wherein the underbody protection (1) is characterized in that the plurality of ribs are monolithically connected to the base plate.

Description

[0001] The present invention relates to an underbody protection for motor vehicles, in particular for electric vehicles. Furthermore, the present invention relates to a motor vehicle, in particular an electric vehicle, with an underbody protection and a method for producing an underbody protection.

[0002] Various types of underbody protection systems are known from the state of the art. Heavy steel plates or welded steel assemblies are primarily used as underbody protection to absorb the high intrusion force and impact energy when vehicles dynamically impact obstacles. Such underbody protection systems increase the overall vehicle weight. In addition, underbody protection made of steel poses an increased risk of corrosion.

[0003] DE 10 2013 017 955 A1 discloses a motor vehicle comprising a floor element with at least one cover element, wherein a stiffening structure is connected to the cover element. The motor vehicle is characterized in that the cover element is formed from a fiber composite material, wherein the stiffening structure is designed as a honeycomb core or a foam core.

[0004] From DE 10 2021 118 286 A1, an underbody protection element for a motor vehicle is known, comprising a formed core element made of a thermosetting fiber matrix semi-finished product and at least one reinforcing element made of a glass fiber reinforced thermosetting material, wherein the at least one reinforcing element is materially connected to the core element.

[0005] Multilayer, fiber-reinforced impact protection structures with honeycomb cores or corrugated layer structures are known from DE 10 2020 131 876 A1. A multilayer impact protection structure comprises a first layer with continuous fibers embedded in a polymer matrix, a second layer attached to the first layer and containing an elastomeric polymer, and a third layer attached to a side of the first layer opposite the second layer, wherein the third layer contains a fiber-reinforced polymer honeycomb structure and / or a corrugated structure.

[0006] From DE 10 2019 135 323 A1, an underbody protection element for a motor vehicle is known, comprising a flat core element made of a first thermoplastic material, at least one lower and one upper cover layer made of a second fiber-reinforced, thermoplastic material, wherein the cover layers are formed and integrally connected to the core element.

[0007] From US 8 961 724 B1 a structural panel is known comprising a closed-cell foam core made of a metallic material, a first carbon fiber panel connected to a first side of the closed-cell foam core, and a second carbon fiber panel connected to a second side of the closed-cell foam core, wherein the foam core is arranged between the first carbon fiber panel and the second carbon fiber panel.

[0008] The invention is based on the object of providing an underbody protection which has high rigidity and energy absorption capacity while at the same time being lightweight.

[0009] The object underlying the present invention is achieved by an underbody protection having the features of claim 1. Advantageous embodiments of the underbody protection are described in the claims dependent on claim 1.

[0010] More specifically, the object underlying the present invention is achieved by an underbody protection for a motor vehicle, which comprises at least a first protective element, a support structure with a plurality of ribs, and at least one second protective element. The support structure is sandwiched between the first protective element and the second protective element and connected to each of them, wherein the ribs extend between the first protective element and the second protective element, so that a plurality of cavities are formed between the first protective element and the second protective element.

[0011] The underbody protection according to the invention has the advantage that the protective effect of the underbody protection against mechanical impact, for example due to an impact, is increased. In the event of a mechanical impact, for example due to an impact caused by a motor vehicle dynamically touching down on a surface, the second protective element can deform into the cavities of the support structure and convert the energy generated by the impact into mechanical deformation energy. The first protective element is protected from deformation due to the deformation of the second protective element into the cavities of the underbody protection, so that components of the motor vehicle located above the first protective element are effectively protected. The underbody protection therefore has an increased protective effect against mechanical impact.

[0012] The underbody protection is designed for a motor vehicle, in particular for an electrically powered vehicle.

[0013] The first protective element and / or the second protective element may also be referred to as the first protective plate and / or the second protective plate.

[0014] According to the feature that the support structure is arranged in a sandwich-like manner between the first protective element and the second protective element, at least parts of the support structure are arranged, at least in sections, in a sandwich-like manner between the first protective element and the second protective element. For example, the ribs are arranged in a sandwich-like manner between the first protective element and the second protective element.

[0015] The first protective element and / or the second protective element can be designed as a substantially flat component. A substantially flat component within the meaning of the present invention has a first direction of extent, a second direction of extent, and a third direction of extent. The third direction of extent is significantly smaller than the first direction of extent and the second direction of extent. The third direction of extent can also be referred to as the thickness direction. The first direction of extent can also be referred to as the longitudinal direction. The second direction of extent can also be referred to as the width direction. All three directions of extent are orthogonal to one another.

[0016] The first protective element may have a first connecting surface. The first connecting surface may be arranged parallel to the plane spanned by the longitudinal extent and the width extent of the first protective element. In other words, the first connecting surface may be arranged orthogonal to the thickness extent of the first protective element.

[0017] The second protective element may have a second connecting surface. The second connecting surface may be arranged parallel to the plane spanned by the longitudinal extent and the width extent of the second protective element. In other words, the second connecting surface may be arranged orthogonal to the thickness extent of the second protective element.

[0018] According to the invention, the support structure comprises a base plate from which the majority of the ribs extend. The base plate of the support structure can be designed as a substantially flat component.

[0019] According to the feature that the support structure has a plurality of ribs, it is meant that the support structure has at least two ribs. A first subset of the ribs can, for example, be aligned parallel to one another, and a second subset of the ribs can be aligned crossed with the first subset of ribs.

[0020] The support structure may comprise a plastic, in particular a thermoplastic and / or thermosetting plastic.

[0021] The support structure can be made of fiber-reinforced plastic, at least in sections. This can improve the flexural rigidity of the underbody protection.

[0022] The support structure can contain long fibers and / or continuous fibers. This can further improve the flexural rigidity of the underbody protection.

[0023] The fibers of the support structure can be formed as glass fibers and / or carbon fibers and / or aramid fibers.

[0024] According to the feature that the support structure is arranged in a sandwich-like manner between the first protective element and the second protective element and is connected to each of them, this means that, starting from the first protective element, the support structure is arranged first and connected to the first protective element. In particular, the first protective element is connected to the support structure in such a way that the thickness of the first protective element runs at least partially parallel to the thickness of the base plate of the support structure. The second protective element is arranged on the support structure and connected to it in such a way that the thickness of the base plate of the support structure and the thickness of the second protective element run at least partially parallel to one another. In other words, the first protective element and the second protective element are arranged on two opposite sides of the support structure and are connected to the support structure.

[0025] The ribs may extend between the first protective element and the second protective element such that the plurality of cavities are defined by the first protective element and the base plate of the support structure. Alternatively or additionally, the cavities may be defined by the first protective element and the second protective element.

[0026] The majority of the cavities may have a width and / or a length in a range of 10 mm to 100 mm, preferably in a range of 30 mm to 60 mm.

[0027] The ribs may extend in a regular pattern between the first protective element and the second protective element. The ribs may extend along the longitudinal and / or lateral extents of the base plate of the support structure and form a regular pattern. This improves the flexural rigidity of the underbody protection.

[0028] The ribs may have a wall thickness in a range of 1.5 mm to 8 mm, preferably in a range of 2 mm to 4 mm.

[0029] The first protective element and / or the second protective element can partially cover the ribs of the support structure. This allows for increased flexibility of the underbody protection.

[0030] Alternatively, the first protective element and / or the second protective element can completely cover the ribs of the support structure. This can achieve increased flexural rigidity of the underbody protection.

[0031] The first protective element and / or the second protective element can be connected to the support structure by means of connecting elements. Connecting elements can be designed as screws, rivets, or other connecting elements. For example, a cavity with an undercut or a through-hole can be formed in the first protective element and / or in the second protective element. The material of the support structure can extend into the cavity, thus forming a rivet. Furthermore, the material of the support structure can extend through a through-hole, the wall of which is preferably chamfered, thus forming a rivet.

[0032] The support structure may have connecting receptacles configured to connect the first protective element and / or the second protective element to the support structure by means of connecting elements. The connecting receptacles may be arranged on the plurality of ribs.

[0033] The underbody protection can comprise a plurality of first protective elements and second protective elements. This allows increased flexibility of the underbody protection to be achieved. Preferably, the support structure comprises a base plate from which the majority of the ribs extend.

[0034] The correspondingly designed underbody protection has even better stability and is particularly easy to manufacture.

[0035] The majority of the ribs can extend orthogonally from the base plate of the support structure. This can simplify the manufacture of the support structure.

[0036] According to the invention, the majority of the ribs are monolithically connected to the base plate. Monolithically connected components are two components manufactured from a single, continuous piece. In particular, monolithically connected components are seamlessly connected to one another.

[0037] Preferably, the support structure is shell-shaped.

[0038] The correspondingly designed underbody protection has even better stability and is particularly easy to manufacture.

[0039] A shell-shaped component within the meaning of the invention has at least one substantially planar portion and at least one edge portion that at least partially delimits the planar portion and has a component orthogonal to the planar portion. The delimiting edge portion can also be referred to as a boundary edge.

[0040] The boundary edge can be monolithically connected to the base plate.

[0041] The support structure may have a receiving volume which is at least partially delimited by the base plate and the boundary edge.

[0042] The boundary edge can completely enclose the base plate of the support structure. In other words, the receiving volume can be completely limited by the boundary edge in the direction of the longitudinal and lateral extensions of the base plate.

[0043] The support structure can be designed as a monolithic component.

[0044] The first protective element can be arranged in the receiving volume of the support structure. This makes it easier to install the underbody protection on a motor vehicle.

[0045] The underbody protection preferably has a connecting flange arranged on the edge.

[0046] The connecting flange is preferably formed as part of the support structure. This simplifies the manufacture of the support structure. Furthermore, the flexural rigidity of the support structure is increased.

[0047] The connecting flange can extend away from the edge of the support structure, in particular in the direction of the width and / or the length of the base plate of the support structure.

[0048] The connecting flange can have an extension in the direction of the width and / or the length of the base plate of the support structure in a range of 8 mm to 40 mm, preferably in a range of 10 mm to 18 mm. This allows the underbody protection to be connected to a motor vehicle in an improved manner.

[0049] The connecting flange may have a joining surface. The joining surface may be configured to establish a connection to a motor vehicle or to a motor vehicle component, such as a traction battery. The connection to the motor vehicle may be a material connection. Alternatively or additionally, a mechanical connection may be established using connecting elements. Connecting elements may be designed as screws, rivets, or other mechanical connecting elements.

[0050] The connecting flange can be formed as part of the boundary edge.

[0051] The connecting flange can be designed as a connecting flange surrounding the support structure.

[0052] Preferably, the first protective element is / are formed as a first organic sheet and / or the second protective element is / are formed as a second organic sheet.

[0053] Organic sheets are fiber-matrix semi-finished products. These consist of a fiber fabric or fiber mesh embedded in a thermoplastic matrix. This can improve hot formability and thus shorten production times. Furthermore, the flexural rigidity of the underbody protection can be improved.

[0054] The first protective element and / or the second protective element can be made of the same plastic as the support structure. This allows for improved connection, in particular improved welding, of the first protective element and / or the second protective element to the support structure.

[0055] Preferably, the first protective element is / are formed as a first metal sheet and / or the second protective element is / are formed as a second metal sheet.

[0056] A protective element constructed from a metal sheet exhibits improved isotropic mechanical and thermal properties. This can, in particular, improve the isotropic behavior of the underbody protection.

[0057] A first metal sheet and / or a second metal sheet may comprise a steel alloy and / or an aluminum alloy.

[0058] The first protective element and / or the second protective element can be partially or completely enclosed by the support structure, in particular by a plastic material of the support structure. This allows the first protective element and / or the second protective element to be better protected against corrosion.

[0059] The first protective element can partially protrude into the connecting flange. In other words, the first protective element can be partially enclosed by a material of the connecting flange. This increases the flexural rigidity of the underbody protection, particularly in the area of ​​the connecting flange.

[0060] Preferably, the first protective element and / or the second protective element has / have a wall thickness in a range of 0.1 mm to 6 mm, preferably in a range of 0.5 mm to 4 mm, more preferably in a range of 1 mm to 3 mm.

[0061] The inventors have discovered that even with surprisingly thin protective elements, the protective effect of the underbody protection against mechanical impacts is considerably improved compared to underbody protection devices known from the prior art and, at the same time, the weight is reduced.

[0062] Preferably, the support structure is designed as a plastic component, preferably as a fiber-reinforced plastic component.

[0063] The correspondingly designed underbody protection exhibits further improved stability and is particularly easy to manufacture. Furthermore, the support structure can be manufactured in a simplified manner, particularly off-tool, through injection molding, thermoforming, and / or extrusion and / or compression molding.

[0064] The support structure may comprise thermoplastic material, preferably polypropylene or polyamide.

[0065] Alternatively, the support structure can be made of thermosetting plastic.

[0066] Preferably, the support structure has a thickness in the range of 5 mm to 25 mm, preferably in the range of 8 mm to 20 mm, more preferably in the range of 10 mm to 16 mm.

[0067] This allows the weight of the underbody structure to be further reduced and the efficiency of a motor vehicle with an appropriately designed underbody protection to be further increased.

[0068] Preferably, a first connecting surface of the first protective element is / are connected to the support structure by means of micro-form locking and / or a second connecting surface of the second protective element is / are connected to the support structure by means of micro-form locking.

[0069] The correspondingly designed underbody protection is particularly simple, as it can be manufactured at least partially without the use of tools. Furthermore, the correspondingly designed underbody protection offers even greater stability.

[0070] A micro-form fit within the meaning of the invention is understood to be a form fit between two components, whereby one component is at least partially engaged by the other component at a plurality of points. This allows for improved form fit with increased joining force. Furthermore, it allows for improved joining of two components made of different materials, such as plastic and metal.

[0071] Preferably, the first connecting surface and / or the second connecting surface has a microsurface structure.

[0072] The microsurface structure of the first connecting surface and / or the second connecting surface is / are produced, for example, by means of a laser microstructuring process and / or by means of sandblasting or corundum blasting and / or by means of an etching process.

[0073] Preferably, a first connecting surface of the first protective element is / are connected to the support structure and / or a second connecting surface of the second protective element is / are connected to the support structure in a materially bonded manner.

[0074] A material connection can be achieved, for example, by welding and / or gluing the support structure to the first connecting surface and / or the second connecting surface.

[0075] Preferably, a first adhesion promoter layer is / are applied to the first connecting surface and / or a second adhesion promoter layer is / are applied to the second connecting surface.

[0076] The adhesion promoter layer can achieve an improved bond, in particular an improved material bond.

[0077] The adhesion promoter layer can be formed as a heat-activated adhesive layer, preferably in the form of a film, a lacquer, and / or a powder coating. The powder coating can be based on a thermoplastic or thermosetting material. This allows for a further improved material bond between the support structure and the first and second protective elements.

[0078] The adhesion promoter layer can have a layer thickness in a range of 0.02 mm to 3 mm, preferably in a range of 0.03 mm to 1 mm, more preferably in a range of 0.05 mm to 0.3 mm.

[0079] The object underlying the present invention is also achieved by a motor vehicle, in particular an electric vehicle, with an underbody protection as described above, which is attached to an underbody of the motor vehicle, in particular to a traction battery of the motor vehicle.

[0080] The underbody protection according to the invention can be produced by a method for producing an underbody protection as described above, the method comprising the following method steps: - Creating a support structure; - Inserting a first protective element into a first joining tool; - Inserting the support structure into the first joining tool; - Connecting the first protective element to the support structure; - Inserting a second protective element into the first joining tool or into a second joining tool; - Inserting the support structure into the second joining tool; - Connecting the second protective element to the support structure.

[0081] The support structure can be manufactured using an injection molding process, a thermoforming process, or an extrusion process. Alternatively, the support structure can be manufactured using a compression molding process using a thermosetting sheet molding compound (SMC).

[0082] The first protective element and / or the second protective element can be connected to the support structure by welding. Alternatively or additionally, the connection can be made by screwing, riveting, or clamping.

[0083] The production of the support structure and the insertion of the first protective element can be performed in a single step. In other words, the first protective element can be inserted into a mold first, and then the support structure can be produced in the same mold by overmolding and / or overmolding the first protective element. This allows for an improved material bond between the support structure and the first protective element.

[0084] The production of the support structure and the insertion of the second protective element can be performed in a single step. In other words, the second protective element can be inserted into a mold first, and then the support structure can be produced in the same mold by overmolding and / or overmolding the second protective element. This allows for an improved material bond between the support structure and the second protective element.

[0085] Further advantages, details, and features of the invention will become apparent from the following exemplary embodiments. In detail, they show: Fig. 1: a schematic sectional view of an underbody protection according to the invention according to a first embodiment; Fig. 2: a schematic, perspective sectional view of an underbody protection according to the invention according to the first embodiment; Fig. 3: a perspective view of an underbody protection according to the invention according to the first embodiment; and Fig. 4: a perspective view of a support structure of an underbody protection according to the invention according to a second embodiment; Fig. 5: a schematic sectional view of an underbody protection according to the invention according to a third embodiment.

[0086] In the following description, identical reference numerals designate identical components or identical features, so that a description given with reference to one figure regarding a component also applies to the other figures, thus avoiding repetitive description. Furthermore, individual features described in connection with one embodiment can also be used separately in other embodiments.

[0087] Fig. Figure 1 shows a first embodiment of an underbody protection 1 according to the invention for a motor vehicle in a sectional view. The underbody protection 1 comprises a first protective element 10 and a second protective element 20, and a support structure 30 sandwiched between the first protective element 10 and the second protective element 20. The first protective element 10 and the second protective element 20 are connected to the support structure 30 on two opposite sides thereof.

[0088] The support structure 30 has a plurality of ribs 31 extending orthogonally from a base plate 32 of the support structure 30. The plurality of ribs 31 also extends between the first protective element 10 and the second protective element 20, so that a plurality of cavities 2 are formed between the first protective element 10 and the second protective element 20.

[0089] The plurality of ribs 31 are monolithically connected to the support structure 30. The plurality of ribs 31 extend in the direction of the width and length of the support structure 30 and form a regular pattern.

[0090] The first protective element 10 has a first connecting surface 11, and the second protective element 20 has a second connecting surface 21. The first protective element 10 is connected to the ribs 31 of the support structure 30 by means of the first connecting surface 11. The second protective element 20 is connected to the base plate 32 of the support structure 30 by means of the second connecting surface 21.

[0091] The underbody protection 1 also has a connecting flange 33 arranged on the edge. The connecting flange 33 is monolithically connected to the support structure 30. The connecting flange 33 extends away from the support structure 30 in the direction of the longitudinal extent and the width extent of the base plate 32. The connecting flange 33 is designed as a connecting flange 33 that extends around the support structure 30.

[0092] The support structure 30 is shell-shaped. The support structure 30 has a boundary edge 34. The boundary edge 34 and the base plate 32 partially delimit a receiving volume 40.

[0093] The first protective element 10 is accommodated in the receiving volume 40 of the support structure 30.

[0094] In the installed position of the underbody protection 1, the second protective element 20, then the support structure 30, and then the first protective element 10 are arranged starting from a substrate. Thus, in the event of a mechanical impact, for example, caused by an impact caused by a motor vehicle with an underbody protection 1 touching down, the second protective element 20 can deform into the cavities 2 of the support structure 30. This allows energy from the impact to be converted into mechanical deformation energy. Thus, the components of a motor vehicle arranged starting from a substrate above the underbody protection 1 are better protected.

[0095] Fig. Figure 2 shows a perspective sectional view of the underbody protection 1 according to the first embodiment. The boundary edge 34 has a greater extension in the extension direction of the ribs 31 than the ribs 31. This allows the first protective element 10 to deform further in the event of an impact without striking a component of a vehicle. This allows an increased amount of mechanical deformation energy to be absorbed.

[0096] Fig. Figure 3 shows a perspective view of an underbody protection 1 according to the first embodiment. The first protective element 10 partially covers the plurality of ribs 31 of the support structure 30. This increases the flexibility of the underbody protection.

[0097] Fig. Figure 4 shows a perspective view of a support structure 30 of a second embodiment of an underbody protection 1. The support structure 30 has connection receptacles 35 for receiving connecting elements. This allows the first protective element 10 and / or the second protective element 20 to be connected to the support structure using connecting elements such as screws or rivets.

[0098] Fig. Figure 5 shows a third embodiment of an underbody protection 1 for a motor vehicle in a sectional view. The first protective element 10 partially protrudes into the connecting flange 33 of the support structure 30, so that the first connecting surface 11 of the first protective element 10 is connected to both the plurality of ribs 31 and the connecting flange 33. This further increases the flexural rigidity of the underbody protection 1. List of reference symbols 1 underbody protection 2 Cavity (of the underbody protection) 10 first protective element / organic sheet / metal plate 11 first connecting surface (of the first protective element) 20 second protective element / organic sheet / metal plate 21 second connecting surface (of the second protective element) 30 Support structure / plastic component 31 Rib (of the supporting structure) 32 Base plate (of the support structure) 33 Connecting flange 34 Boundary edge 35 connection recordings 40 recording volume

Claims

[1] Underbody protection (1) for a motor vehicle, comprising: - at least one first protective element (10); - a support structure (30) having a plurality of ribs (31); and - at least one second protective element (20), wherein - the support structure (30) is sandwiched between the first protective element (10) and the second protective element (20) and is connected to each of them, - wherein the ribs (31) extend between the first protective element (10) and the second protective element (20), so that a plurality of cavities (2) are formed between the first protective element (10) and the second protective element (20), and - wherein the support structure (30) has a base plate (32) from which the plurality of ribs (31) extend, wherein the underbody protection (1) characterized by is that the majority of the ribs are monolithically connected to the base plate. [2] Underbody protection (1) according to claim 1, characterized by that the support structure (30) is shell-shaped. [3] Underbody protection (1) according to one of the preceding claims, characterized by that the underbody protection (1) has a connecting flange (33) arranged on the edge. [4] Underbody protection (1) according to one of the preceding claims, characterized by that the first protective element (10) is / are designed as a first organic sheet (10) and / or the second protective element (20) is / are designed as a second organic sheet (20). [5] Underbody protection (1) according to one of the preceding claims, characterized by that the first protective element (10) is / are designed as a first metal sheet (10) and / or the second protective element (20) is / are designed as a second metal sheet (20). [6] Underbody protection (1) according to one of the preceding claims, characterized bythat the first protective element (10) and / or the second protective element (20) has / have a wall thickness in a range of 0.1 mm to 6 mm, preferably in a range of 0.5 mm to 4 mm, more preferably in a range of 1 mm to 3 mm. [7] Underbody protection (1) according to one of the preceding claims, characterized by that the support structure (30) is designed as a plastic component (30), preferably as a fiber-reinforced plastic component (30). [8] Underbody protection (1) according to one of the preceding claims, characterized by that the support structure (30) has a thickness in the range of 5 mm to 25 mm, preferably in the range of 8 mm to 20 mm, more preferably in the range of 10 mm to 16 mm. [9] Underbody protection (1) according to one of the preceding claims, characterized bythat a first connecting surface (11) of the first protective element (10) is / are connected to the support structure (30) by means of micro-form locking and / or a second connecting surface (21) of the second protective element (20) is / are connected to the support structure (30) by means of micro-form locking. [10] Underbody protection (1) according to claim 9, characterized by that the first connecting surface (11) and / or the second connecting surface (21) has a micro-surface structure. [11] Underbody protection (1) according to one of the preceding claims, characterized by that a first connecting surface (11) of the first protective element (10) is / are materially connected to the support structure (30) and / or a second connecting surface (21) of the second protective element (20) is / are materially connected to the support structure (30). [12] Underbody protection (1) according to claim 11, characterized bythat a first adhesion promoter layer is / are applied to the first connecting surface (11) and / or that a second adhesion promoter layer is / are applied to the second connecting surface (21). [13] Motor vehicle, in particular electric motor vehicle, with an underbody protection (1) according to one of claims 1 to 12, which is fastened to an underbody of the motor vehicle, in particular to a traction battery of the motor vehicle.

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