Connection node for a longitudinal beam for attaching to an end wall of a body shell for an electric vehicle

Abstract

The invention relates to a connection node for a longitudinal beam for connecting to an end wall of a body shell for an electric vehicle with a vehicle coordinate system, comprising at least the following components: - a connection for a longitudinal beam with a longitudinal extent along the x-axis of the vehicle coordinate system; - a first node foot which is designed to bend centrally from the longitudinal extent and has a first connection on the end wall side; - a second node foot, which is designed to bend outwards from the longitudinal extension and has a second connection on the end wall side; and - a third node base, which is designed to bend downwards from the longitudinal extension and has a third connection on the end wall, wherein the node bases can be connected to a longitudinal beam via the connection, forming an extension along its longitudinal extension, and can only be connected to a structural frame by means of their connections. The connection node is characterized in particular by the fact that the node bases can only be connected to a longitudinal beam and to a plane spanned by an end wall. The connection node described here proposes an easily assembled and cost-effective structure as part of a crash structure.

Description

[0001] The invention relates to a connection node for a longitudinal member for connecting to a front wall of a bodyshell for an electric vehicle, an assembly method with such a connection node for a connection node, and an electric vehicle with such a connection node.

[0002] The electrification of motor vehicles is giving rise to a new bodyshell concept with regard to the arrangement of vehicle components, crash safety, and lightweight construction, as well as cost-effective manufacturability and assembly. In the event of a frontal crash, for example, so-called longitudinal members with a longitudinal extension in the x-direction (pointing rearward) of a vehicle coordinate system are provided to absorb the loads. In previously known solutions, such a longitudinal member is connected to the rest of the bodyshell with a connecting rail along the x-axis beyond the plane of the bulkhead. This entails an increase in the overall height (in the z-direction) and / or a reduction in the installation space for a traction battery.

[0003] EP 1 970 291 A1 discloses a front body structure, a center side member, and a method for assembling the same. A center frame portion 40 is configured such that a front end portion is connected to a front side frame 1 via a suspension frame fastening bolt 61 to fix a suspension frame, a center portion extends to a tunnel portion 14 provided at the center portion in the vehicle width direction so as to protrude upward, and a rear portion is provided below (vehicle outer side) an upper corner portion of the tunnel portion 14 so as to extend along the upper corner portion.Accordingly, there may be provided a vehicle front structure having a pair of front side frames provided on both sides of a vehicle body so as to extend in a vehicle longitudinal direction, which can properly distribute the load even when a larger frontal impact load acts.

[0004] Based on this, the present invention is based on the object of at least partially overcoming the disadvantages known from the prior art. The features of the invention are derived from the independent claims, for which advantageous embodiments are presented in the dependent claims. The features of the claims can be combined in any technically reasonable manner, whereby the explanations from the following description as well as features from the figures, which comprise additional embodiments of the invention, can also be consulted for this purpose.

[0005] The invention relates to a connection node for a longitudinal member for connecting to a front wall of a body shell for an electric vehicle with a vehicle coordinate system, comprising at least the following components: - a connection for a longitudinal member with a longitudinal extension along the x-axis of the vehicle coordinate system; - a first node base which is designed to bend centrally from the longitudinal extent and has a first connection on the end wall side; - a second node base, which is designed to bend outwards from the longitudinal extension and has a second connection on the end wall side; and - a third node foot, which is designed to bend downwards from the longitudinal extension and has a third connection on the end wall, wherein the node feet can be connected via the connection to a longitudinal beam to form an extension along its longitudinal extension and can be connected to a shell exclusively by means of their connections.

[0006] The connection node is characterized primarily by the fact that the node feet can only be connected to a longitudinal beam and to a plane spanned by an end wall.

[0007] In the following, reference is made to a (Cartesian) vehicle coordinate system with an x-axis pointing opposite the direction of travel, a y-axis pointing toward the left side of the vehicle, and a z-axis pointing upwards, unless explicitly stated otherwise, when the axial direction, radial direction, or circumferential direction and corresponding terms are used. An alignment along an axis or plane is not strictly mathematical, but rather a technical one (with possible deviations: offsets, undulations, inclinations) for design requirements and thus an approximate alignment in or parallel to the axis or plane for the level of detail of the description.Unless explicitly stated otherwise, ordinal numbers used in the preceding and following descriptions serve only to clearly distinguish them and do not reflect the order or ranking of the designated components. An ordinal number greater than one does not necessarily imply that another such component must be present.

[0008] A bodyshell is also referred to as a vehicle body and is self-supporting or connected to a chassis (frame, chassis, or subframe). The longitudinal member of a bodyshell for a motor vehicle, preferably for an electric vehicle with at least one electric drive motor and a traction battery supplying this with an electrical power voltage, is proposed here to be attached to the bulkhead with a connection node designed as a three-part node. The connection node is not the only connection between the longitudinal member and the rest of the bodyshell along its longitudinal extent. Furthermore, the connection node is connected exclusively to the bulkhead of the bodyshell, apart from the connection with which the connection node is connected to the longitudinal member.

[0009] It should be noted that the longitudinal member is not necessarily perfectly aligned along the x-axis (longitudinal direction), nor is the force to be absorbed necessarily perfectly aligned along the x-axis of the vehicle's coordinate system. In one embodiment, the longitudinal member has a lateral offset (S-shape) so that, in a frontal crash, energy is dissipated in the area of ​​this lateral offset and, above all, the transmission of an x-axis force is mitigated.

[0010] Furthermore, it should be noted that the vehicle coordinate system is defined differently: one (as used here) with the x-axis pointing forward (in the direction of travel) or, conversely, with the x-axis pointing backward. However, the z-axis always points upward. The y-axis is aligned according to the Cartesian system. In principle, however, any other definition is possible and feasible.

[0011] It should also be noted that two longitudinal beams are provided, which are preferably designed in a mirrored, identical manner. These two longitudinal beams are spaced apart along the y-axis. Between the two longitudinal beams is an inner region, which is outer relative to the x-axis. The longitudinal beams are arranged in a common xy-plane, and the z-direction toward the surface being driven on is referred to as below or below.

[0012] Furthermore, it should be noted that the connection node (and not the longitudinal member) extends longitudinally beyond the end wall. However, this does not rule out the possibility of a connecting element (e.g. a screw or weld seam) extending beyond this plane. Furthermore, the plane spanned by the end wall is not a mathematically flat surface, but rather a component with elevations and depressions, for example a (usually formed) sheet metal element, such as a formed metallic sheet and / or an (often fiber-reinforced) organic sheet. A (formed) metallic sheet is preferably cold-formed by embossing, punching, drawing, and / or deep-drawing. An organic sheet is formed, i.e. shaped, in an appropriate mold (e.g. with a thermoset as the matrix material) in an autoclave or during (e.g. injection-) molding (e.g. with a thermoplastic as the matrix material).

[0013] The connection node comprises a (first) inner node foot, a (second) outer node foot, and a (third) lower node foot. The shape of the connection node enables adjustment in the x-direction, y-direction, and z-direction. In one embodiment, adjustment in the x-direction is possible via the connection, which defines an assembly direction between the connection and the longitudinal member along the x-axis with a required assembly tolerance. In one embodiment, adjustment in the y-direction and / or z-direction is possible via the end wall-side connections, which define an assembly area between the connections and the end wall in a (not necessarily common, but at least parallel) assembly plane spanned by the y-axis and the z-axis with a required assembly tolerance.

[0014] The inner node foot is a (not necessarily formed) bent or arched component which, for force transmission, points centrally (or inwards) from the longitudinal direction towards the end wall at an incline. In one embodiment, the inner node foot comprises a section which is aligned parallel to the longitudinal extent of the longitudinal member, wherein the connection or a component of the connection is preferably formed by this section. The end wall-side (inner) connection is preferably formed flat in the yz plane. The end wall-side (inner) connection is preferably designed as a flange surface, wherein a plurality of flanges or a fully or partially circumferential flange is designed to point outwards with respect to the connection axis (which is oblique to the end wall) or with respect to a central axis of the connection region of the inner node foot that is parallel to the x-axis.

[0015] The outer node base is a (not necessarily reshaped) bent or arched component that points outwardly from the longitudinal direction toward the end wall, inclined to transmit force. In one embodiment, the outer node base comprises a section that is aligned parallel to the longitudinal extension of the longitudinal member, with this section preferably forming the connection or a component of the connection. The end wall-side (outer) connection is preferably formed flat in the yz plane (particularly preferably in the same way as the inner connection).The end wall-side (outer) connection is preferably designed (particularly preferably in the same way as or similarly to the inner connection) as a flange surface, wherein a plurality of flanges or a completely or partially circumferential flange is designed to point outwards, relative to the connection axis (which is oblique to the end wall) or relative to a central axis of the connection region of the outer node foot which is parallel to the x-axis.

[0016] The lower node base is a (not necessarily reshaped) bent or arched component that points downwards from the longitudinal direction toward the end wall for force transmission. In one embodiment, the lower node base comprises a section that is aligned parallel to the longitudinal extension of the longitudinal member, with this section preferably forming the connection or a component of the connection. The end wall-side (lower) connection is preferably formed flat in the yz plane (particularly preferably in the same way as the inner connection and / or outer connection).The end wall-side (lower) connection is preferably designed (particularly preferably in the same way or similarly to the inner connection and / or outer connection) as a flange surface, wherein a plurality of flanges or a completely or partially circumferential flange is designed to point outwards, relative to the connection axis (which is oblique to the end wall) or relative to a central axis of the connection region of the lower node foot which is parallel to the x-axis.

[0017] The respective connection area forms a geometric shape, for example a rectangle or a circle, whereby the geometric shape has a center, for example a center of gravity or a load center averaged by means of an integral, whereby the central axis runs through this center along the x-axis. A force transmission along the longitudinal member thus leads, by means of the node feet, to a diversion or derivation of the (e.g. pure) x-force into a shear force component (y-force and z-force), i.e. an introduction of a resultant force in the plane of the bulkhead, and / or an introduction of a moment. This in turn leads to good energy dissipation and good attenuation of the transmission of the x-force introduced from the front (for example in a frontal crash) along the x-axis into the bulkhead and the components behind it, as well as the passenger cell.

[0018] The flanges or other fastening sections of the respective connections of the node feet to the end wall are preferably designed such that a support is formed against shear forces along the x-axis and along the y-axis or against a torsional moment about the x-axis, preferably in pairs on the outside of the respective center of the connection plane (for example, left and right or bottom and top).

[0019] The connection is designed for the force-transmitting connection of the connection node to a longitudinal member. In one embodiment, all node feet are combined to form a directly contacting connection. Alternatively, one or more (for example, two) of the node feet are combined to form a directly contacting connection, while the other node feet are only in indirect force-transmitting contact with the longitudinal member. Preferably, each of the node feet has a section with a longitudinal extension. Alternatively, at least one node foot is connected to the longitudinal member and / or to at least one other node foot (in a force-transmitting manner) at an angle to the longitudinal extension.

[0020] Furthermore, there is a free space between the node feet for a steering column.

[0021] The steering column can be arranged between the inner node foot, the outer node foot, and the lower node foot, where the free space is formed. Conventionally, a connection node of the longitudinal member is formed between the steering column and the bulkhead. However, this does not always provide sufficient installation space for the design (crash) loads. In a suitable embodiment, the connection node is designed such that the steering column is arranged along the x-axis overlapping only one of the node feet, for example the inner node foot, and / or preferably such that the steering column pivots the steering wheel forward (along the x-axis) away from the driver (around the y-axis) when such a crash load is applied (or x-force introduced along the relevant longitudinal member).

[0022] It is further proposed in an advantageous embodiment of the connection node that at least one, preferably all, of the node feet can be connected to a longitudinal beam in an overlapping manner along the longitudinal extent, preferably can be inserted into a longitudinal beam, and / or Preferably, the longitudinal member has a web with two surface sides, which is positively enclosed by the connection formed by the node feet on both sides of the surface sides.

[0023] Here, it is proposed that a node base have a section that, when assembled, is connected to the connected longitudinal member in an overlapping manner. This achieves high connection rigidity and good energy transfer between the components in the event of deformation, for example, through co-deformation, sliding friction, and / or a long transmission tolerance distance for large deformations (compared to an opposite extreme example with a butt joint, in which the force transmission is interrupted or at least indefinitely impaired upon the destruction of this connection). Furthermore, a large connection surface is offered for a (preferably redundant) connection between the components, while simultaneously maintaining good adjustment tolerance.

[0024] In a preferred embodiment, the connection can be inserted into the longitudinal member, for example, like two pipes that can be connected to one another with an overlap in the pipe direction. Alternatively or additionally, the longitudinal member can be inserted (at least partially) into the connection of the connection node. Alternatively, there is no insertion, but rather a parallel arrangement, for example like Tetris pieces. Preferably, a separate component, for example a sheet metal element and / or cast component, is provided, which has an undercut formed along the x-axis, i.e. a raised area and / or a recess extending along the y-axis and / or z-axis. This makes it difficult to (forcefully) release the plug-in connection. At the same time, assembly is very simple.

[0025] In one embodiment, the longitudinal member has a web, for example, within a tubular profile, for example, with a planar extension along an xy plane. In one embodiment, this web is achieved to further increase force transmission by enlarging the contact area and / or providing additional contact area with additional stiffening lever support, thus providing friction, levering, and ultimately energy distribution. Alternatively or additionally, the web can also be used to ensure correct assembly.

[0026] It is further proposed in an advantageous embodiment of the connection node that an overlap element is provided, and the overlap element is connected in an overlapping manner to at least one of the node feet and / or can be connected in an overlapping manner to the longitudinal member, wherein the overlap element is preferably formed from a shaped sheet metal.

[0027] By means of an overlap element, as already shown, the contact area can be enlarged and / or an undercut can be formed, while at the same time ensuring easy assembly and manufacturability of the components in question. Furthermore, the overlap element (especially in the case of sheet metal elements) creates a material thickening and / or stiffening and / or increased energy absorption capacity (also by means of the separating surfaces, among other things). In one embodiment, an overlap is formed for one or more directions, for example for the y-axis (for example only on the outside) and / or z-axis (for example only at the top). It should be noted that a high energy absorption capacity in this context means that in the event of a crash load, an introduced force is absorbed by the components and its transmission is limited and preferably also redirected, for example around a passenger cabin and / or a traction battery.The energy is absorbed, for example, by deformation, tearing, breaking, shear distortion and / or friction.

[0028] In one embodiment, the overlap element is formed so as to overlap one of the node feet, preferably a plurality (for example two) node feet. In one embodiment, the overlap element is designed so as to overlap the longitudinal member connected by means of the connection of the connecting node. Preferably, the overlap element is formed so as to overlap at least one of the node feet and the connected longitudinal member. In one embodiment, the connection can be inserted into a longitudinal member (for example as described above) and is enclosed by the overlap element circumferentially around the longitudinal extent of the connection (for example x-axis) or such an overlap region is extended along the x-axis.

[0029] In one embodiment, a geometrically simple structure is formed so that a shaped sheet metal can be used. The overlap element preferably has an L-shape or U-shape with its main extension solely in the xy-plane and the xz-plane and is used as an extension of the longitudinal extension of the longitudinal member. The overlap element is preferably also configured to deflect forces from the longitudinal extension, for example, along the y-axis.

[0030] It is further proposed in an advantageous embodiment of the connection node that the connection of at least one of the node feet comprises at least one shaped sheet metal element, wherein preferably at least one of the sheet metal elements is connected in an overlapping manner to a further component of the respective node foot and / or a further sheet metal element of the respective node foot.

[0031] Here, it is proposed that the connection to the end wall of one of the node feet, preferably of each of the node feet, comprises a formed sheet metal element or is formed by one or exclusively by several formed sheet metal elements. A formed sheet metal element is easy and cost-effective to manufacture and also has excellent properties for mechanical connection, both with regard to the connection technology (e.g., by means of flow-drilled screws and / or adhesive bonding) and with regard to energy absorption capacity under a crash load.

[0032] In a preferred embodiment, an overlap is formed, so that (as already explained above) a high degree of stability of such a connection and a high energy absorption capacity for crash loads are achieved. This is particularly achieved or reinforced by the large contacting interface between two flat elements (preferably formed sheet metal elements).

[0033] It is further proposed in an advantageous embodiment of the connection node that at least one, preferably all, of the node feet comprise an extruded profile, preferably an extruded aluminum profile, and / or wherein preferably a component of the connection is formed by the extruded profile or the extruded profile is arranged between the connection and the respective connection.

[0034] An extruded profile offers the advantage of allowing a closed cross-section geometry for high torsional rigidity and high energy absorption capacity for crash loads, and / or a more complex cross-section geometry (e.g., with a web and / or a flange) to be achieved cost-effectively than with a sheet metal element. An extruded profile can also be bent and / or twisted using simple means, allowing the desired inclinations and shapes to form the geometry of the connection node to be easily and cost-effectively adjusted and, if necessary, even adjusted during assembly.

[0035] In one embodiment, the inner node foot and the outer node foot are formed entirely from an extruded profile, or apart from the respective connection to the end wall (i.e., including the connection). In one embodiment, the lower node foot is multi-part, for example, three-part, preferably also comprising an extruded profile. Preferably, (at least for the connection), the respective node foot comprises two or more shell parts, which are connected to the respective extruded profile, and preferably to each other, in an overlapping manner. Such a shell part is a formed sheet metal element or a cast element.

[0036] In one embodiment, aluminum is particularly suitable as a lightweight, and preferably ductile, material. An aluminum extruded profile can also be manufactured particularly cost-effectively.

[0037] It should be noted that the connection is preferably formed exclusively by the extruded profiles of the node feet, with the previously described overlap element preferably also being provided, which is not assigned to a single node foot, but overlaps several node feet. Alternatively, when connecting one, several, or all of the node feet, an element (e.g., a cast element or sheet metal element) is interposed, and the respective extruded profile is in exclusively indirect, i.e., not direct, contact with the longitudinal beam to be connected.

[0038] It is further proposed in an advantageous embodiment of the connection node that the connection of at least one of the node feet comprises at least one cast element, wherein preferably the at least one cast element is connected in an overlapping manner to a further component of the respective node foot and / or a further sheet metal element of the respective node foot.

[0039] This design takes advantage of a cast element, which can often be manufactured cost-effectively while simultaneously having a highly complex geometry.

[0040] Another (independent) advantage of a cast element is that, thanks to its often low ductility but high fracture energy absorption, a good energy absorption capacity for crash loads can be achieved. The properties of a cast element are particularly advantageous when used with a good connection to a sheet metal element and / or an extruded profile for crash loads. Due to their high ductility, these elements yield to displacement and deformation of the cast element and can continue to transmit force even if the cast element fractures.

[0041] The different mechanical properties of the components of a node base are particularly well utilized when these components are formed in an overlapping manner, preferably in the area of ​​the respective connection to the end wall. For further explanation, please refer to the above description.

[0042] It is further proposed in an advantageous embodiment of the connection node that overlapping sections are connected to each other in a form-fitting and material-fitting manner, preferably by means of a flow-hole screw, particularly preferably without pre-drilling, and / or preferably bonded using adhesive distributed over the entire surface.

[0043] An overlap creates a large, flat connection area, providing high energy absorption capacity under crash load through friction and / or shear. A purely form fit, for example, using an undercut, ensures reliable force transfer. A purely material fit, for example, using adhesive, soldering, and / or welding, requires high shear forces and / or transverse forces to separate the components. A point-based material fit promotes a tendency toward relative or counter-deformation, thus creating additional energy absorption capacity.

[0044] It should be noted that in one embodiment, a surface-distributed adhesive is not applied over the entire surface during assembly, but is applied in strips and is only distributed more or less during joining.

[0045] Furthermore, it should be noted that a flow-drilled screw, together with an adhesive applied at specific points or over a large area, has particularly good properties with regard to damping (to avoid disruptive noise emissions from components that move relative to one another during operation) and energy absorption capacity. It should be noted that in one embodiment (with a pilot hole), a flow-drilled screw is used to flow-form one of two flat elements to form a (long) thread, or (for example, without a pilot hole) two adjacent flat elements are welded together when forming the (long) thread. Furthermore, it should be noted that more than two elements can also be connected to one another using a (single) flow-drilled screw, with an adjacent pair being screwed together in each case, with or without being welded together.

[0046] According to a further aspect, an assembly method for a connection node according to an embodiment as described above is proposed, comprising the following steps: a. Providing and joining the components of the node feet of the connection node together; b. Providing and joining at least the connection-side components of the node feet to one another and thus forming a connection for connection to a longitudinal member; c. Providing a longitudinal member of a shell; d. Providing an end wall of a shell; e. Connecting and adjusting along the longitudinal extent of the connection of the node feet formed in step b. with the longitudinal beam provided in step c.; f. Connecting and adjusting along at least one of the directions transverse to the longitudinal extent of the connections of the node feet to the end wall provided in step d., wherein the steps are preferably carried out according to the alphabetical order.

[0047] The connection node proposed here (at least in one embodiment) is particularly simple and cost-effective to install. At the same time, the connection node offers maximum safety for load absorption in a crash scenario, for example, according to IIHS2023 [Insurance Institute for Highway Safety] and / or US / Euro NCAP [New Car Assessment Program]. Regarding the installation procedure, reference is made to the previous description in connection with the previously described connection node, without exclusion of generality, at least analogously applicable.

[0048] In one embodiment, one, several, or each of the node feet is first assembled, for example, at a supplier for an OEM (original equipment manufacturer). Such a node foot is then provided as a pre-assembled unit. Preferably, two or all of the node feet are joined together and provided as a pre-assembled unit. Alternatively, (at least) one of the node feet is only assembled on-site during the assembly of the bodyshell.

[0049] In one embodiment, at least one component of several or all node feet, for example, the extruded profiles, are joined together to form a connection, with the respective (end wall-side) connection not yet joined. Alternatively, one, several, or all node feet are already joined together, i.e., a pre-assembled unit (including connection) before these (at least partially pre-assembled) node feet are joined together. In one embodiment, the side members and the bulkhead are provided independently. Preferably, at least the bulkhead is already assembled with at least part of the remaining bodyshell. In one embodiment, one or both of the side members are already assembled with other components of a vehicle, for example, with components of a bumper, an engine mount, and / or other components.

[0050] The longitudinal extension of a longitudinal member is adjusted during assembly by the connection of the respective connection node. In one embodiment, the connection node is already pre-assembled with the end wall (e.g., not yet adjusted in the yz plane) or assembled (e.g., already adjusted relative to the end wall) during adjustment.

[0051] The position of a connection node or a longitudinal member is adjusted during assembly from the respective (end wall-side) connection of the connection node or individually for each of the connections, preferably exclusively in the yz plane. In one embodiment, the respective longitudinal member is already pre-assembled with the respective connection node (e.g., not yet adjusted in its longitudinal extent) or assembled (e.g., already adjusted relative to the respective longitudinal member) during adjustment.

[0052] The order of the steps is based on the distribution of production steps within a production line, across different companies, or even spontaneously based on component availability. The alphabetical order is ideal for production on a single production line with optimal component availability, as it allows the tolerance chain to be fully considered in steps e. and f., while the individual (pre-)assembly can be carried out without taking this into account.

[0053] It is further proposed in an advantageous embodiment of the assembly method that overlapping sections in step a., step b., step e. and / or step f. are connected to each other in a form-fitting and material-fitting manner, preferably by means of a flow-drilling screw, particularly preferably without pre-drilling, and / or preferably bonded using adhesive distributed over the entire surface.

[0054] According to a further aspect, an electric vehicle is proposed, comprising at least the following components: - a body shell with a bulkhead and an energy storage unit arranged behind the bulkhead along the x-axis of its vehicle coordinate system; - two longitudinal members, which are each connected to the end wall by means of a connection node according to an embodiment as described above in front of the end wall, preferably mounted by means of an assembly method according to an embodiment as described above; - at least one electric drive machine; - at least one voltage source for supplying the at least one electric drive machine with an electrical power voltage; and - at least one drive wheel which can be supplied with a torque by at least one of the electric drive motors to propel the electric vehicle.

[0055] The electric vehicle is designed, for example, as described above. The electric vehicle is driven purely electrically for its propulsion (via the at least one drive wheel), i.e., with one (single) or multiple electric drive motors, which in turn are driven by the power voltage of a voltage source, for example, a traction battery. Alternatively or additionally, a fuel tank, for example, a hydrogen tank, is provided, by means of which an electrical voltage can be generated with the aid of a (so-called hot or cold) fuel cell or in another way (for example, with a so-called range extender engine [internal combustion engine with generator]). In one embodiment, the electric vehicle is designed with two axles, with one or both axles having an electric drive motor, which can be used simultaneously or alternately to propel the electric vehicle.

[0056] In one embodiment, an electric drive motor for a drive axle of the electric vehicle is provided in front of (i.e., behind in the direction of travel) the bulkhead. In one embodiment, a trunk is arranged in front of the bulkhead. Alternatively or additionally, other components and / or storage compartments are provided.

[0057] In one embodiment, a transport compartment, such as a passenger cabin, is located behind (i.e., in front of) the bulkhead. This transport compartment must be protected as best as possible from the effects of force introduction in a crash scenario, especially a frontal crash, i.e., by providing the best possible energy absorption and / or energy redirection around the transport compartment.

[0058] The voltage source, for example a traction battery and / or a fuel tank (with or without a fuel cell), is preferably accommodated in a corresponding frame element of the bodyshell (preferably in an underbody beneath a transport compartment), behind (i.e. in front of) the bulkhead or opposite the (at least, preferably exactly two) longitudinal members, i.e. separated from each other by the bulkhead acting as a partition (approximately in the yz plane). Thus, as seen from the longitudinal members, it is arranged behind the bulkhead. The electrical voltage source must also be protected as best as possible from the effects of force introduction in a crash scenario, especially a frontal crash, whereby the forces or jolt here may often be considerably greater than in a passenger cabin.

[0059] The (at least two) longitudinal members are configured, on the one hand, as a supporting structure for a body of the electric vehicle. On the other hand, they are configured as part of a crash structure for absorbing crash energy and / or redirecting a crash load. The connection node described herein is particularly suitable for this purpose, especially for a large receiving space for a voltage source in the underbody of the electric vehicle, and is also easy and cost-effective to manufacture and assemble.

[0060] The invention described above is explained in detail below against the relevant technical background with reference to the accompanying drawings, which show preferred embodiments. The invention is in no way limited by the purely schematic drawings, whereby it should be noted that the drawings are not to scale and are not suitable for defining proportions. It is shown in Fig. 1: a mounted connection node between a longitudinal member and an end wall; Fig. 2: the mounted connection node according to Fig. 1 between a longitudinal member and a bulkhead with steering column; Fig. 3: in a side view of the mounted connection node according to Fig. 1 between a longitudinal member and a bulkhead; Fig. 4: the connection node according to Fig. 1 with a longitudinal beam before joining; Fig. 5: an (e.g. inner) node foot in an exploded view; Fig. 6: an (e.g. outer) node foot in an exploded view; Fig. 7: a (for example lower) node foot in an exploded view; Fig. 8: a flow chart of the assembly process; and Fig. 9: A schematic plan view of a battery-electric vehicle.

[0061] In Fig. 1 shows a mounted connection node 1 between a (left) longitudinal member 2 and a bulkhead 3 in a spatial view from the left front outside. The vehicle coordinate system is shown with respect to a direction of travel (in the viewing direction) of a motor vehicle with the x-axis 8 oriented rearward, here in the illustration pointing to the left and slightly into the image plane, with the y-axis 9 to the right in the direction of travel, in the illustration to the left into the image plane, and the z-axis 10 upwards, here approximately vertically. The longitudinal extent 7 of the longitudinal member 2 is aligned (approximately) along the x-axis 8. The bulkhead 3 is aligned here approximately spanning a yz-plane. Centrally in the illustration is an opening 39 for a steering column 18 (not shown here, compare Fig. 2).

[0062] Here it can be seen that in the extension of the longitudinal extent 7 of the longitudinal member 2 in the direction towards the end wall 3, a free space 17 is formed, on the sides of which a node foot 11, 13, 15 is arranged inwards (here left), outwards (here right) and downwards. The connection 6 of the connection node 1 is inserted into the longitudinal member 2 (in longitudinal extent 7) and covered by an overlap element 22. At the end wall 3, the node feet 11, 13, 15 are connected to a respective (end wall-side) connection 12, 14, 16. It should be noted that the structural connection of the individual components is not explicitly shown here. In this view, only a flow-hole screw 32 is representatively shown on the outer node foot 13 at the connection 6 of the connection node 1. Further details are explained in the following figures.In this exemplary embodiment (purely optional), the connections 12, 14, 16 all have a (interrupted or over a partial section) circumferential flange extending outwards from the central axis, by means of which they are connected to the end wall 3 at the respective connection area (preferably adjustable in the yz plane).

[0063] It should be noted that the number and arrangement of fasteners in this and the following illustrations, such as the flow-hole screw 32 and adhesive, are not shown here in a level of detail that claims completeness, and the fasteners shown or their arrangement do not represent any limitation of implementation.

[0064] In Fig. 2 is the mounted connection node 1 according to Fig. 1 between a (left) longitudinal member 2 and a bulkhead 3 with steering column 18 in a spatial view from the front right centrally. The vehicle coordinate system is shown here with the x-axis 8 pointing rearward and left out of the image plane, the y-axis 9 pointing left and slightly out of the image plane, and the z-axis 10 approximately vertical.

[0065] Here, the lower connection 16 of the lower node foot 15 and the inner connection 12 of the inner node foot 11 are clearly visible. Furthermore, a steering column 18 is shown in the created free space 17, which is guided through the opening 39 of the end wall 3. It can also be seen here that the connection 6 of the connection node 1 on the inner side of the longitudinal member 2 is enclosed by the latter itself, and that the overlap element 22 ends approximately centrally in the upper area. Inside the longitudinal member 2, shown here in section, a web 19 with an upper surface side 20 and a lower surface side 21 can be seen, which web extends along the longitudinal extension 7 to the connection 6 of the connection node 1 (cf. Fig. 4). Behind the front wall 3, a cross member 46, or rather a multi-part structure of a cross member 46, can be seen. The lower connection 16 is connected in an overlapping manner to the cross member 46 located at the rear of the front wall 3 (in this illustration) and is thus very well supported.

[0066] In Fig. 3 is a side view of the mounted connection node 1 according to Fig. 1 between a longitudinal member 2 and an end wall 3, wherein the end wall 3 is shown in section with a cross member 46 (in the direction of view of the image plane) just in front of the lower connection 16 of the lower node base 15. The vehicle coordinate system is shown here with the x-axis 8 pointing to the right, the y-axis 9 pointing perpendicularly into the image plane, and the z-axis 10 vertically.

[0067] In this view of the lower connection 16, it is clearly visible that the (purely optional three) components of the lower node base 15 are arranged with a large overlap. Specifically here (with reference to the exploded view in Fig. 7) below the cast element 31 adjacent to the (fifth) sheet element 27 and the lower extruded profile 30, as well as the fifth sheet element 27 adjacent to the lower extruded profile 30.

[0068] In Fig. 4 is the connection node 1 according to Fig. 1 (with the same spatial orientation) with a longitudinal beam 2 before joining, whereby the connection 6 of the connection node 1 and the insertion receptacle of the longitudinal beam 2 including the web 19 are clearly visible. The overlap element 22 is shown raised according to an exploded view, so that the already in Fig. 2 and its upper surface 20 become visible. It can be seen here that the connection 6 of the connection node 1 is formed jointly by all three node feet 11, 13, 15, which are pre-assembled (here representatively by means of flow-hole screws 32) to form a structural unit (here purely optionally already including their connections 12, 14, 16). The connection 6 of the connection node 1 here has a receiving slot 40, which, when the connection 6 is inserted into the longitudinal member 2, is in force-transmitting contact with the web 19 of the longitudinal member 2 (at least under a bending crash load).

[0069] In Fig. 5 is an example of an inner node foot 11 in an exploded view, such as in Fig. 1 to Fig. 4. The main part or the component for the connection 6 of the connection node 1 comprising and deflecting part is here an (inner) extruded profile 28. The (inner) connection 12 is here exclusively made up of a first sheet metal element 23 and a second sheet metal element 24, each with a flange section 49 for connection to the end wall 3 (see Fig. 1) formed.

[0070] In Fig. 6 is an example of an outer node foot 13 in an exploded view, such as in Fig. 1 to Fig. 4. The main part or the component for the connection 6 of the connection node 1 comprising and deflecting part is here an (outer) extruded profile 29. The (outer) connection 14 is here exclusively made up of a third sheet metal element 25 and a fourth sheet metal element 26, each with a flange section 49 for connection to the end wall 3 (see Fig. 1) formed.

[0071] In Fig. 7 is an example of a lower node foot 15 in an exploded view, such as in Fig. 1 to Fig. 4. The main part or the component for the connection 6 of the connection node 1 comprising and deflecting part is here a (lower) extruded profile 30. The (lower) connection 16 is here exclusively made up of a fifth sheet metal element 27 and a cast element 31, each with a flange section 49 for connection to the end wall 3 (see Fig. 1) formed. In Fig. 8 is a flow chart of the assembly method for a connection node 1, such as shown in the preceding figures, with a preferred order (represented alphabetically by dashed arrows). The group of steps a., b. and c., as well as the group of steps e. and f., can each be carried out in any order, for example almost simultaneously in one workstation. Here, it is proposed that in a step a. the components of the node feet 11, 13, 15 of the connection node 1 are provided and joined together. Preferably, then in a step b. the connection-side components of the node feet 11, 13, 15 are provided (one after the other or simultaneously) and then joined together, thus forming a connection 6 for connecting to the provided longitudinal member 2. Preferably, then in a step c. a longitudinal member 2 of a bodyshell 4 is provided. Now, in a step d.an end wall 3 of a shell 4 is provided. In this exemplary embodiment, in a step e. (preferably subsequently), the previously formed connection 6 of the node feet 11, 13, 15 is connected and adjusted to the previously provided longitudinal member 2 along the longitudinal extension 7. Finally, in a step f., the connections 12, 14, 16 of the node feet 11, 13, 15 are connected and adjusted to the provided end wall 3 along at least one of the directions (in the yz plane) transverse to the longitudinal extension 7.

[0072] In Fig. Figure 9 shows a schematic plan view of a battery-powered electric vehicle 5. The vehicle coordinate system is shown here with the x-axis 8 pointing rearward (to the left in the illustration), the y-axis 9 pointing rightward (downward in the image plane), and the z-axis 10 pointing upward (out of the image plane).

[0073] An electrical voltage source 36, here embodied as a traction battery, is arranged centrally beneath the transport space 43. In this embodiment, two electric drive motors 34, 35 can be supplied with a power voltage by means of the voltage source 36. A left drive wheel 37 and a right drive wheel 38 of a rear axle 48 can be driven by means of the rear drive motor 34 to propel the electric vehicle 5, wherein a transmission 41 and a differential 42 are shown here (purely optional). A left drive wheel 37 and a right drive wheel 38 of a front axle 47 can be driven by means of the front drive motor 35 to propel the electric vehicle 5, wherein the front drive motor 35 is configured as a coaxial drive motor here (purely optional).

[0074] The aforementioned components of the electric vehicle 5 are held by a body shell 4, which for this purpose has a central energy storage receptacle 33, which in this embodiment also supports the transport space 43. At the rear of the electric vehicle 5, a left rear carrier 44 and a right rear carrier 45 are provided, which are designed here, among other things, to support the rear drive motor 34 (or the entire rear part of the drive train). A cross member 46 is provided in front of the energy storage receptacle 33 or the transport space 43, and on this, in turn, a front wall 3 (compare, for example, Fig.2). Again, a longitudinal member 2 is provided on the left and right in front of the bulkhead 3, which supports the front drive unit 35 (or the entire front part of the drive train) and, if applicable, a trunk. Furthermore, the longitudinal members 2 are responsible for absorbing crash loads, at least in the event of a frontal impact.

[0075] The connection node described here proposes an easy-to-assemble and cost-effective structure as part of a crash structure.

Claims

[1] Connection node (1) for a longitudinal member (2) for connecting to a front wall (3) of a body shell (4) for an electric vehicle (5) with a vehicle coordinate system, comprising at least the following components: - a connection (6) for a longitudinal member (2) with a longitudinal extension (7) along the x-axis (8) of the vehicle coordinate system; - a first node foot (11) which is designed to bend centrally from the longitudinal extension (7) and has a first connection (12) on the end wall side; - a second node foot (13) which is designed to bend outwards from the longitudinal extension (7) and has a second connection (14) on the end wall; and - a third node foot (15) which is designed to bend downwards from the longitudinal extension (7) and has a third connection (16) on the end wall, wherein the node feet (11, 13, 15) can be connected via the connection (6) to a longitudinal beam (2) forming an extension along its longitudinal extension (7) and are connected exclusively by means of their Connections (12,14,16) can be connected to a shell (4), characterized by , that the node feet (11, 13, 15) can be connected exclusively to a longitudinal member (2) and to a plane spanned by an end wall (3), wherein a free space (17) for a steering column (18) is formed between the node feet (11, 13, 15). [2] Connection node (1) according to claim 1, wherein at least one of the node feet (11, 13, 15) can be connected to a longitudinal beam (2) in an overlapping manner along the longitudinal extension (7). [3] Connection node (1) according to claim 2, wherein can be inserted into a longitudinal beam (2), and / or the longitudinal beam (2) has a web (19) with two surface sides (20, 21), which is positively enclosed by the connection (6) formed by means of the node feet (11, 13, 15) on both sides of the surface sides (20, 21). [4] Connection node (1) according to one of the preceding claims, wherein an overlap element (22) is provided, and the overlap element (22) is connected in an overlapping manner to at least one of the node feet (11, 13) and / or can be connected in an overlapping manner to the longitudinal member (2). [5] Connection node (1) according to one of the preceding claims, wherein the connection (12, 14, 16) of at least one of the node feet (11, 13, 15) comprises at least one shaped sheet metal element (23, 24, 25, 26, 27). [6] Connection node (1) according to one of the preceding claims, wherein at least one of the node feet (11, 13, 15) comprises an extruded profile (28, 29, 30). [7] Connection node (1) according to one of the preceding claims, wherein the connection (16) of at least one of the node feet (15) comprises at least one cast element (31). [8] Assembly method for a connection node (1) according to one of the preceding claims, comprising the following steps: a. Providing and joining the components of the node feet (11, 13, 15) of the connection node (1) together; b. Providing and joining at least the connection-side components of the node feet (11, 13, 15) to one another and thus forming a connection (6) for connection to a longitudinal member (2); c. Providing a longitudinal member (2) of a shell (4); d. Providing an end wall (3) of a shell (4); e. connecting and adjusting along the longitudinal extent (7) of the connection (6) of the node feet (11, 13, 15) formed in step b. with the longitudinal beam (2) provided in step c.; f. Connecting and adjusting along at least one of the directions transverse to the longitudinal extension (7) of the connections (12,14,16) of the node feet (11,13,15) with the end wall (3) provided in step d. [9] Assembly method according to claim 8, wherein overlapping sections in step a., step b., step e. and / or step f. are connected to one another in a form-fitting and material-fitting manner. [10] Electric vehicle (5), comprising at least the following components: - a body shell (4) with a front wall (3) and an energy storage receptacle (33) arranged behind the front wall (3) along its x-axis (8) of its vehicle coordinate system; - two longitudinal beams (2) which are connected to the end wall (3) in front of the latter by means of a respective connection node (1) according to one of claims 1 to 7; - at least one electric drive machine (34,35); - at least one voltage source (36) for supplying the at least one electric drive machine (34, 35) with an electrical power voltage; and - at least one drive wheel (37, 38) which can be supplied with a torque by at least one of the electric drive motors (34, 35) for propelling the electric vehicle (5).

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