Underbody protection for motor vehicles, motor vehicle with underbody protection

Abstract

Underbody protection (1) for a motor vehicle, comprising at least a first protective element (10), a support structure (30) with a plurality of ribs (31) and at least a second protective element (20), wherein the support structure (30) is arranged sandwich-like between the first protective element (10) and the second protective element (20) and is connected to each of them, and 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), wherein the underbody protection (1) is characterized in that the support structure (30) is shell-shaped.

Description

The present invention relates to an underbody protection for motor vehicles, in particular for electric motor vehicles. Furthermore, the present invention relates to a motor vehicle, in particular an electric motor vehicle having an underbody protection and a method for producing an underbody protection.Various types of underbody protection systems are known from the prior art. Heavy steel plates or steel welding assemblies are predominantly used as under-floor guards to absorb the high intrusion force and impact energy when dynamic motor vehicles are placed on obstacles. Such underbody protection systems increase overall vehicle weight. In addition, an underbody protection made of steel has an increased risk of corrosion.In particular, DE 10 2013 017 955 A1 discloses an underbody protection element having two cover elements and a reinforcing structure.DE 10 2019 135 323 A1 discloses an underbody protection element made of thermoplastic plastic material for a motor vehicle, wherein the core element is, however, injected as an extrusion material between two cover plates, resulting in low rigidity.The object of the invention is to provide an underbody protection which has a high rigidity and energy absorption capacity while at the same time being light in weight.The object underlying the present invention is achieved by means of an underbody protection having the features of claim 1. Advantageous embodiments of the underbody protection are described in the claims dependent on claim 1.More specifically, the object underlying the present invention is achieved by an underbody protection for a motor vehicle, which has at least one first protection element, a supporting structure having a plurality of ribs and at least one second protection element. The support structure is sandwiched between and connected to the first protective member and the second protective member, respectively, the ribs extending between the first protective member and the second protective member, so that a plurality of voids are formed between the first protective member and the second protective member.The underbody protection according to the invention has the advantage that the protective effect of the underbody protection against a mechanical action by, for example, an impact is increased. The second protective element can deform into the cavities of the supporting structure in the event of a mechanical action, for example by an impact due to a dynamic placement of a motor vehicle on a substrate, and thereby convert arising energy into mechanical deformation energy by the impact. The first protective element is protected against deformation due to the deformation of the second protective element into the cavities of the underbody protector, so that components of the motor vehicle located above the first protective element are effectively protected. As a result, the underbody protection has an increased protective effect with respect to mechanical action.The underbody protection is designed for a motor vehicle, in particular for an electrically driven vehicle.The first protection element and / or the second protection element can also be referred to as a first protection plate and / or a second protection plate.According to the feature that the supporting structure is arranged in a sandwich-like manner between the first protective element and the second protective element, at least parts of the supporting 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 sandwiched between the first protection member and the second protection member.The first protective element and / or the second protective element can be designed as an essentially planar component. A substantially planar component in the sense of the present invention has a first direction of extension, a second direction of extension and a third direction of extension. The third direction of extension is significantly smaller than the first direction of extension and the second direction of extension. The third direction of extension can also be referred to as thickness extension. The first direction of extension can also be referred to as longitudinal extension. The second direction of extension can also be referred to as width extension. All three directions of extension are orthogonal to one another.The first protection element may have a first connection surface. The first connecting surface can be arranged parallel to the planes spanned by the longitudinal extension and the width extension of the first protective element. In other words, the first connecting surface can be arranged orthogonally to the thickness extension of the first protective element.The second protection element may have a second connection surface. The second connecting surface can be arranged parallel to the planes spanned by the longitudinal extension and the width extension of the second protective element. In other words, the second connecting surface can be arranged orthogonally to the thickness extension of the second protective element.The support structure may comprise a base plate. The base plate of the supporting structure can be designed as a substantially planar component.According to the feature that the support structure comprises a plurality of ribs, it is meant that the support structure comprises at least two ribs. For example, a first subset of the ribs may be oriented parallel to each other and a second subset of the ribs may be oriented crossed to the first subset of the ribs.The supporting structure can comprise a plastic, in particular a thermoplastic and / or thermosetting plastic.The supporting structure can be designed at least in sections as a fiber-reinforced plastic. This allows the bending rigidity of the underbody shield to be improved.The support structure can comprise long fibers and / or endless fibers. As a result, the bending rigidity of the underbody shield can be further improved.The fibers of the supporting structure can be formed as glass fibers and / or carbon fibers and / or aramid fibers.According to the feature that the support structure is arranged in a sandwiched manner between the first protective element and the second protective element and is respectively connected thereto, it is meant that, starting from the first protective element, the support structure is arranged first and is 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 extension of the first protective element runs at least partially parallel to the thickness extension of the base plate of the support structure. The second protective element is arranged on the supporting structure and connected thereto in such a way that the thickness extension of the base plate of the supporting structure and the thickness extension of the second protective element run parallel to one another at least in sections. In other words, the first protective element and the second protective element are arranged on the supporting structure on two mutually opposite sides of the supporting structure and are connected thereto.The ribs may extend between the first protective element and the second protective element such that the plurality of cavities are bounded by the first protective element and the base plate of the support structure. Alternatively or additionally, the cavities can be bounded by the first protective element and the second protective element.The plurality of cavities can have a width extension and / or a longitudinal extension in a range from 10 mm to 100 mm, preferably in a range from 30 mm to 60 mm.The ribs may extend in a regular pattern between the first protection element and the second protection element. The ribs can extend along the longitudinal extension and / or the width extension of the base plate of the support structure and form a regular pattern. This improves the bending rigidity of the underbody shield.The ribs can have a wall thickness in a range from 1.5 mm to 8 mm, preferably in a range from 2 mm to 4 mm.The first protective element and / or the second protective element can partially cover the ribs of the supporting structure. This allows increased flexibility of the underbody protection to be achieved.Alternatively, the first protective element and / or the second protective element can completely cover the ribs of the supporting structure. This allows an increased bending stiffness of the underbody shield to be achieved.The first protective element and / or the second protective element can be connected to the supporting 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, so that a rivet is formed in this way. Furthermore, the material of the supporting structure can extend through a through-hole, the wall of which is preferably beveled, so that a rivet is formed in this way.The support structure can have connecting receptacles which are configured to connect the first protective element and / or the second protective element to the support structure by means of connecting elements. The connection receptacles may be arranged on the plurality of ribs.The underbody guard may include a plurality of first guard members and second guard members. This allows increased flexibility of the underbody protection to be achieved. Preferably, the support structure comprises a base plate from which the plurality of ribs extend.The correspondingly designed underbody protection has an even further improved stability and can be produced particularly easily.The plurality of ribs may extend orthogonally away from the base plate of the support structure. This allows simplified production of the supporting structure.The plurality of ribs may be monolithically connected to the base plate. Monolithically connected are two components which are manufactured from one coherent piece. In particular, monolithically connected components are connected to one another without joints.According to the invention, the supporting structure is designed in the form of a shell.The correspondingly designed underbody protection has an even further improved stability and can be produced particularly easily.A shell-shaped component in the sense of the invention has at least one substantially planar section and at least one edge section, which at least partially delimits the planar section and has a component orthogonal to the planar section. The delimiting edge section can also be referred to as a delimiting edge.The boundary edge can be monolithically connected to the base plate.The supporting structure can have a receiving volume which is at least partially delimited by the base plate and the delimiting edge.The boundary edge can completely enclose the base plate of the support structure. In other words, the receiving volume can be completely delimited by the delimiting edge in the direction of the longitudinal extent and the width extent of the base plate by the delimiting edge.The supporting structure can be designed as a monolithic component.The first protective element can be arranged in the receiving volume of the supporting structure. As a result, the underbody protection can be mounted on a motor vehicle in a simplified manner.The underbody protection preferably has a connecting flange arranged on the edge.The connecting flange is preferably formed as part of the supporting structure. As a result, the supporting structure can be produced in a simplified manner. In addition, the bending stiffness of the supporting structure is thereby increased.The connecting flange can extend away from the support structure on the edge side, in particular in the direction of the width extension and / or the longitudinal extension of the base plate of the support structure.The connecting flange can have an extension in the direction of the width extension and / or the longitudinal extension of the base plate of the supporting structure in a range from 8 mm to 40 mm, preferably in a range from 10 mm to 18 mm. As a result, the underbody protection can be connected to a motor vehicle in an improved manner.The connecting flange can have a joining surface. The joining surface can be configured to produce a connection to a motor vehicle or to a motor vehicle component, such as a traction battery. The connection to the motor vehicle can be a cohesive connection. Alternatively or additionally, a mechanical connection can be produced by means of connecting elements. Connecting elements can be designed as screws, rivets or other mechanical connecting elements.The connecting flange can be formed as part of the boundary edge.The connecting flange can be designed as a connecting flange encircling the supporting structure.Preferably, the first protective element is / are designed as a first organo sheet and / or the second protective element is / are designed as a second organo sheet.Organoplates are to be understood as meaning semi-finished fibre-matrix products. These consist of a woven fiber fabric or a laid fiber fabric embedded in a thermoplastic matrix. As a result, the hot workability can be improved and thereby the manufacturing times can be shortened. In addition, the bending stiffness of the underbody shield can be improved.The first protective element and / or the second protective element can comprise the same plastic as the supporting structure. As a result, the first protective element and / or the second protective element can be connected to the supporting structure in an improved manner, in particular can be welded in an improved manner.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.A protective element formed as a metal sheet has improved isotropic mechanical and thermal properties. In this way, in particular, the isotropic behavior of the underbody protection can be improved.A first metal sheet and / or a second metal sheet may comprise a steel alloy and / or an aluminum alloy.The first protective element and / or the second protective element can be partially or completely surrounded by the support structure, in particular by a plastic material of the support structure. As a result, the first protective element and / or the second protective element can be protected against corrosion in an improved manner.The first protection element can partially project into the connecting flange. In other words, the first protective element can be partially surrounded by a material of the connecting flange. This increases the bending stiffness of the underbody shield, in particular in the region of the connecting flange.The first protective element and / or the second protective element preferably has / have a wall thickness in a range from 0.1 mm to 6 mm, preferably in a range from 0.5 mm to 4 mm, further preferably in a range from 1 mm to 3 mm.The inventors have found that even with protective elements which are surprisingly designed to be correspondingly thin, the protective effect of the underbody protection against mechanical effects is significantly improved in comparison with underbody protection devices known from the prior art and at the same time the weight is reduced.The supporting structure is preferably designed as a plastic component, preferably as a fiber-reinforced plastic component.The correspondingly designed underbody protection has an even further improved stability and can be produced particularly easily. Furthermore, the supporting structure can be produced in a simplified manner, in particular in a tool-falling manner, by injection molding, thermoforming and / or extrusion and / or compression molding.The supporting structure can comprise thermoplastic, preferably polypropylene or polyamide.Alternatively, the supporting structure can comprise thermosetting plastic.The support structure preferably has a thickness extension in the range from 5 mm to 25 mm, preferably in the range from 8 mm to 20 mm, more preferably in the range from 10 mm to 16 mm.As a result, the weight of the underbody structure can be reduced once more and the efficiency of a motor vehicle having a correspondingly designed underbody protection can be increased once more.Preferably, a first connecting surface of the first protective element is / are connected to the support structure by means of micro-form closure and / or a second connecting surface of the second protective element is / are connected to the support structure by means of micro-form closure.The correspondingly designed underbody protection is particularly simple, since it can preferably be produced at least partially in a tool-falling manner. Furthermore, the correspondingly designed underbody protection has an even further improved stability.A micro-form fit in the sense of the invention is understood to mean a form fit between two components, wherein one component is at least partially engaged behind at a plurality of points by the other component. This makes it possible to achieve an improved positive fit with an increased connecting force. In addition, two components of different materials, such as plastic and metal, can thereby be joined to one another in an improved manner.Preferably, the first connection surface and / or the second connection surface has a micro-surface structure.The micro-surface structure of the first connection surface and / or of the second connection surface is / are produced, for example, by means of a laser characterization method and / or by means of sandblasting or corundum blasting and / or by means of an etching method.Preferably, a first connecting surface of the first protective element is / are connected to the supporting structure in a materially integral manner and / or a second connecting surface of the second protective element is / are connected to the supporting structure in a materially integral manner.A cohesive connection can be achieved, for example, by welding and / or adhesive bonding the supporting structure to the first connecting surface and / or the second connecting surface.Preferably, a first adhesion promoter layer is / are applied to the first connection surface and / or a second adhesion promoter layer is / are applied to the second connection surface.The adhesion promoter layer can achieve an improved connection, in particular an improved cohesive connection.The adhesion promoter layer can be formed as a heat-activatable adhesive layer, preferably in the form of a film, a coating and / or a powder coating. The powder coating can be formed on a thermoplastic or thermosetting basis. This makes it possible to achieve an even improved cohesive connection between the supporting structure and in each case the first protective element and the second protective element.The adhesion promoter layer can have a layer thickness in a range from 0.02 mm to 3 mm, preferably in a range from 0.03 mm to 1 mm, more preferably in a range from 0.05 mm to 0.3 mm.The object underlying the present invention is also achieved by a motor vehicle, in particular an electric vehicle having an underbody protection described above, which is fastened to an underbody of the motor vehicle, in particular to a traction battery of the motor vehicle.The underbody protection according to the invention can be produced by a method for producing an underbody protection described above, wherein the method has the following method steps:producing a supporting structure;inserting a first protective element into a first joining tool;inserting the supporting structure into the first joining tool;connecting the first protective element to the supporting structure;inserting a second protective element into the first joining tool or into a second joining tool;inserting the supporting structure into the second joining tool;connecting the second protective element to the supporting structure.The support structure can be produced by an injection molding process, a thermoforming process or an impact molding process. Alternatively, the support structure can be produced by a pressing method with thermosetting sheet molding compound (SMC).The connection of the first protective element and / or the second protective element to the support structure can be effected by a welding method. Alternatively or additionally, the connection can be effected by a screw connection, a riveting or a clamping.The production of the supporting structure and the insertion of the first protective element can take place in one step. In other words, the first protective element can first be inserted into a tool and then the support structure can be produced in the same tool by over-pressing and / or over-molding the first protective element. As a result, the supporting structure can be connected to the first protective element in an improved materially bonded manner.The production of the supporting structure and the insertion of the second protective element can take place in one step. In other words, the second protective element can first be inserted into a tool and then the support structure can be produced in the same tool by over-pressing and / or over-molding the second protective element. As a result, the supporting structure can be connected to the second protective element in an improved materially bonded manner.Further advantages, details and features of the invention are evident below from the explained exemplary embodiments. In this context, the following show in detail: FIG. 1 : a schematic sectional illustration of an underbody shield according to the invention according to a first embodiment; FIG. 2 : a schematic, perspective sectional illustration of an underbody shield according to the invention according to the first embodiment; FIG. 3 : a perspective illustration of an underbody shield according to the invention according to the first embodiment; and FIG. 4 : a perspective illustration of a supporting structure of an underbody shield according to the invention according to a second embodiment; FIG. 5 : shows a schematic sectional illustration of an underbody shield according to the invention according to a third embodiment.In the description which follows, the same reference numerals designate the same components or the same features, so that a description with respect to a component carried out with respect to a figure also applies to the other figures, so that a repetitive description is avoided. Furthermore, individual features that have been described in connection with an embodiment can also be used separately in other embodiments.FIG. 1 shows a first embodiment of an underbody shield 1 according to the invention for a motor vehicle in a sectional illustration. The underbody protector 1 includes a first protective member 10 and a second protective member 20, and a support structure 30 sandwiched between the first protective member 10 and the second protective member 20. The first protective element 10 and the second protective element 20 are connected to the supporting structure 30 on two mutually opposite sides thereof.The support structure 30 includes a plurality of ribs 31 extending orthogonally away from a base plate 32 of the support structure 30. The plurality of ribs 31 also extend between the first protective member 10 and the second protective member 20 so that a plurality of voids 2 are formed between the first protective member 10 and the second protective member 20.The plurality of ribs 31 are monolithically connected to the support structure 30. The plurality of ribs 31 extend in the width direction and the length direction of the support structure 30, and form a regular pattern.The first protection element 10 has a first connection surface 11 and the second protection element 20 has a second connection surface 21. The first protective element 10 is connected to the ribs 31 of the supporting structure 30 by means of the first connecting surface 11. The second protective element 20 is connected to the base plate 32 of the supporting structure 30 by means of the second connecting surface 21.The underbody protection 1 also has a connecting flange 33 arranged on the edge. The connecting flange 33 is monolithically connected to the supporting structure 30. The connecting flange 33 extends away from the supporting 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 encircling the supporting structure 30.The support structure 30 is designed in the form of a shell. The support structure 30 has a delimiting edge 34. The boundary edge 34 and the base plate 32 partially delimit a receiving volume 40.The first protective element 10 is accommodated in the accommodation volume 40 of the support structure 30.In the installed position of the underbody guard 1, the second protective element 20, then the supporting structure 30 and then the first protective element 10 are arranged first starting from a base. Thus, in the case of a mechanical action caused, for example, by an impact caused by a motor vehicle having an underbody protection 1 being mounted, the second protection element 20 can deform into the cavities 2 of the supporting structure 30. As a result, energy can be converted into mechanical deformation energy by the impact. Thus, the components of a motor vehicle arranged above the underbody guard 1 starting from a ground are protected in an improved manner.FIG. 2 shows a perspective sectional illustration of the underbody shield 1 according to the first embodiment. The boundary edge 34 has a higher extension in the extension direction of the ribs 31 than the ribs 31. As a result, the first protective element 10 can additionally deform in the event of an impact without hitting a component of a vehicle. As a result, an increased amount of mechanical deformation energy can be absorbed.FIG. 3 shows a perspective illustration of an underbody shield 1 according to the first embodiment. The first protection member 10 partially covers the plurality of ribs 31 of the support structure 30. This increases the flexibility of the underbody protection.FIG. 4 shows a perspective illustration of a supporting structure 30 of a second embodiment of an underbody guard 1. the supporting structure 30 has connecting receptacles 35 for receiving connecting elements. As a result, the first protective element 10 and / or the second protective element 20 can be connected by means of connecting elements such as, for example. Screws or rivets can be connected to the supporting structure.FIG. 5 shows a third embodiment of an underbody shield 1 for a motor vehicle in a sectional illustration. The first protection member 10 partially protrudes into the connection flange 33 of the support structure 30, so that the first connection surface 11 of the first protection member 10 is connected to both the plurality of ribs 31 and the connection flange 33. As a result, the bending rigidity of the underbody shield 1 can be increased once more.List of reference characters1 Underbody protection 2 Cavity (of the underbody protection) 10 First protection element / organo sheet / metal plate 11 First connection surface (of the first protection element) 20 Second protection element / organo sheet / metal plate 21 Second connection surface (of the second protection element) 30 Support structure / plastic component 31 Rib (of the support structure) 32 Base plate (of the support structure) 33 Connection flange 34 Boundary edge 35 Connection receptacles 40 Receptacle volume

Claims

Underbody protection (1) for a motor vehicle, having: - at least one first protection element (10); - a supporting structure (30) having a plurality of ribs (31); and - at least one second protection element (20), wherein - the supporting structure (30) is arranged in a sandwich-like manner between the first protection element (10) and the second protection element (20) and is in each case connected thereto, and - wherein the ribs (31) extend between the first protection element (10) and the second protection element (20), such that a plurality of cavities (2) are formed between the first protection element (10) and the second protection element (20), wherein the underbody protection (1) is characterized in that the supporting structure (30) is of shell-shaped design.Underbody protection (1) according to Claim 1, characterized in that the supporting structure (30) has a base plate (32) from which the plurality of ribs (31) extend.Underbody protection (1) according to one of the preceding claims, characterized in that the underbody protection (1) has a connecting flange (33) arranged on the edge.Underbody protection (1) according to one of the preceding claims, characterized in that the first protection element (10) is / are designed as a first organosheet (10) and / or the second protection element (20) is / are designed as a second organosheet (20).Underbody protection (1) according to one of the preceding claims, characterized in that the first protection element (10) is / are designed as a first metal sheet (10) and / or the second protection element (20) is / are designed as a second metal sheet (20).Underbody protection (1) according to one of the preceding claims, characterized in that the first protection element (10) and / or the second protection element (20) has / have a wall thickness in a range from 0.1 mm to 6 mm, preferably in a range from 0.5 mm to 4 mm, further preferably in a range from 1 mm to 3 mm.Underbody protection (1) according to one of the preceding claims, characterized in that the supporting structure (30) is designed as a plastics component (30), preferably as a fibre-reinforced plastics component (30).Underbody protection (1) according to one of the preceding claims, characterized in that the supporting structure (30) has a thickness extension in the range from 5 mm to 25 mm, preferably in the range from 8 mm to 20 mm, further preferably in the range from 10 mm to 16 mm.Underbody protection (1) according to one of the preceding claims, characterized in that a first connecting surface (11) of the first protection element (10) is / are connected to the supporting structure (30) by means of micro-form closure and / or a second connecting surface (21) of the second protection element (20) is / are connected to the supporting structure (30) by means of micro-form closure.Underbody protection (1) according to Claim 9, characterized in that the first connecting surface (11) and / or the second connecting surface (21) has a micro-surface structure.Underbody protection (1) according to one of the preceding claims, characterized in that a first connecting surface (11) of the first protection element (10) is / are connected to the supporting structure (30) in a materially integral manner and / or a second connecting surface (21) of the second protection element (20) is / are connected to the supporting structure (30).Underbody protection (1) according to Claim 11, characterized in that a first adhesion promoter layer is / are applied to the first connecting surface (11), and / or in that a second adhesion promoter layer is / are applied to the second connecting surface (21).Motor vehicle, in particular an electric motor vehicle having 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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