Multi-part bending crossbeam for a vehicle

Abstract

The invention relates to a bending crossbeam for arrangement on a vehicle front, characterized in that the bending crossbeam is made in multiple parts and has a central piece (1) to which a respective end piece (3) is arranged at both ends, wherein the respective end piece (3) is fixedly arranged on the central piece (1) and extends the central piece (1) in its direction of extension by a predetermined length, wherein the respective end piece (3) has a top surface (5) that is lowered relative to the central piece (1).

Description

[0001] The invention relates to a bending cross member for arrangement on a vehicle front, as well as a vehicle with such a bending cross member.

[0002] A flexural cross member in the front of a vehicle serves to ensure the vehicle's own safety in the event of a collision, as well as the safety of any other vehicle involved in the collision. The flexural cross member must therefore meet certain mechanical requirements and is typically designed to ensure compatibility with dissimilar collision partners. This means that, in the event of a relatively high-mass vehicle colliding with a relatively low-mass vehicle, both vehicles involved in the collision should be able to provide adequate occupant protection.

[0003] In the state of the art, various configurations of bending cross members are known, each of which takes into account specific requirements and motivations: In this context, DE 10 2018 008 759 A1 relates to a bumper arrangement for a motor vehicle, comprising a flexible cross member and at least one one-piece deformation element which extends at least over a longitudinal region in overlap with the flexible cross member in the transverse direction of the vehicle and which projects beyond the flexible cross member in the transverse direction of the vehicle with an end region, wherein the end region has a support region which laterally covers an end face of the flexible cross member at least partially in the longitudinal direction of the vehicle.

[0004] The bumper assembly of DE 10 2018 008 759 A1 therefore serves, in particular, to minimize the risk of relative movement of the deformation element to the flexible cross member when a force is applied to the deformation element, at least in the transverse direction of the vehicle, by having an end region of a flexible cross member with a support region that laterally covers an end face of the flexible cross member at least partially in the longitudinal direction of the vehicle. In other words, the support region of the end region laterally covers at least a portion of the end face of the flexible cross member in the transverse direction of the vehicle.

[0005] DE 10 2012 000 457 A1 further relates to a bumper arrangement for a motor vehicle, in particular a passenger car, having a bumper element which comprises a flexible cross member extending at least substantially in the transverse direction of the vehicle and at least one cladding element by means of which the flexible cross member is cladding, wherein at least one deformation element is provided which is arranged in a corner region of the bumper element which is at least partially formed by the cladding element and which is lateral in the transverse direction of the vehicle.

[0006] US 2017 / 0 144 619 A1 describes that, on a front bumper, a support member is mounted on a bent portion of a bumper RF. The support member extends from the bumper RF toward an outer side in the vehicle transverse direction. Therefore, when a pressure pipe is pushed upon a collision of a collision body with a vehicle corner portion, a reaction force is exerted from the support member to the pressure pipe, and the pressure pipe deforms. This makes it possible to detect a collision with a collision body. At this time, when a load of a predetermined value or more is applied to the support member from a rear side, the support member separates from the bumper RF. The support member can be caused to separate from the bumper RF.

[0007] US 2009 / 0 160 204 A1 discloses a corner energy absorber. It comprises a body portion and an arm portion. The body portion includes a top, a bottom, and a front wall extending from the top to the bottom. The corner energy absorber also includes a crush element extending from the front wall of the body portion between the top and bottom of the body portion.

[0008] DE 196 03 954 A1 describes an impact beam for a motor vehicle, which consists of a straight or slightly curved flexible beam and two separate end pieces arranged at both ends of the flexible beam. The flexible beam has recesses extending in the longitudinal direction, at least in its end regions, into which the ends of the end pieces facing the flexible beam can be inserted and secured with a force fit.

[0009] Typically, a flexible cross member is provided below the underside of each of the headlights so that in the event of a collision in which the front of the vehicle is affected by external forces, the flexible cross member can move underneath a headlight without damaging the headlight. Horizontal headlights are often used in automobile construction. These are characterized by the fact that they are wider than they are high when viewed from the front, i.e. the dimensions of such a headlight are larger along the transverse axis of the vehicle than the dimensions along the vertical axis of the vehicle. A horizontal headlight can therefore be arranged relatively easily in relation to the flexible cross member so that in the event of a head-on collision, the flexible cross member can move underneath one or both headlights.

[0010] However, greater design difficulties arise when a so-called vertical headlight is used instead of a horizontal headlight. Unlike a horizontal headlight, the vertical axis of the vehicle is larger than the transverse axis. Viewed from the front of the vehicle, such a vertical headlight is taller than it is wide.

[0011] If, for example, LED headlights are installed near the wheel cutout, the flexible cross member could be shortened to create space for the vertical headlights, but this would have undesirable effects on crash safety. Alternatively, the flexible cross member could be made in a single-piece design with stepped ends in the areas of each headlight, creating more space for the vertical headlight. In order to meet the mechanical requirements by using a closed profile even in the stepped areas, a continuous web would have to be provided that extends in the transverse direction of the vehicle. This web would extend continuously from the left to the right end of the flexible cross member, run in a center section of the flexible cross member within the profile, and form an upper side in the stepped areas.However, this would result in an undesirably high mass input into the bending cross member.

[0012] The object of the invention is therefore to modify a flexible cross member in such a way that the arrangement of headlights on a vehicle front, in particular vertical headlights, can be improved while maintaining the mechanical requirements for a flexible cross member and without any relevant additional mass input.

[0013] The invention is based on the features of the independent claims. Advantageous developments and refinements are the subject of the dependent claims.

[0014] A first aspect of the invention relates to a bending cross member for arrangement on a vehicle front, characterized in that the bending cross member is designed in several parts and has a central piece, to which a respective end piece is arranged at both ends, wherein the respective end piece is fixedly arranged on the central piece and extends the central piece in its direction of extension by a predetermined length, wherein the respective end piece has an upper side which is lowered relative to the central piece.

[0015] The direction of extension of the center section corresponds to a vehicle transverse direction when the bending cross member is installed in the vehicle.

[0016] The multi-part design of the flexible cross member makes it much easier to achieve a lowered profile of the upper side of the flexible cross member in its edge areas in order to achieve a stepped shape in the area of ​​the vehicle's headlights with a lowered upper side, in order to possibly free up installation space for the headlights, particularly in the case of vertical headlights, but especially to maintain freedom of movement of the flexible cross member in the area of ​​its end pieces, which allows the end pieces to move under a respective headlight in the event of a collision of the vehicle in which the front of the vehicle is affected by external forces.

[0017] In this sense, the respective headlight, especially the front headlight, may also include headlight control electronics. Especially with LED headlights, a PCB element ('PCB' is an abbreviation for "printed circuit board") is typically used. This makes it possible, at least in the case of external forces acting on the front of the vehicle that are not too great and occur relatively close to the ground, for a left and right headlight to remain undamaged while the flexible cross member moves under at least one of the headlights in the area of ​​the end pieces.

[0018] For this purpose, the multi-part construction of the flexible cross member is designed such that a center section is provided, which particularly preferably spans at least half of the vehicle's transverse extent. A respective end piece is provided at a left and right end of the center section. Preferably, the respective end piece is inserted into a hollow opening on the respective end face of the center section and permanently secured to the center section using a fixing aid. In particular, but not exclusively, screws, bolts, rivets, but also permanent connections such as welded or adhesive joints can be used.

[0019] To assemble the end pieces into the center piece and to ensure a tight fit between the end pieces and the center piece, an insert section of the respective end piece is preferably inserted into a hollow end face of the center piece. The shapes of the cross sections are adapted accordingly, so that an outer cross section of the respective end piece can be inserted into a respective inner cross section at the respective end of the center piece as closely as possible. Certain tolerances can be compensated for depending on the joining method.

[0020] The type of connection depends on the material selected for the center section and the end sections. Welded and soldered joints are preferred for identical materials, such as steel / steel, magnesium / magnesium, or aluminum / aluminum, or their alloys. In a metallic hybrid solution, i.e., different alloys, a friction stir weld can be used for some material combinations. For a non-metallic hybrid solution, for example, a metallic center section with end sections made of fiber-reinforced composite material, such as CFRP, bonding, screwing, or riveting are used.

[0021] The center piece is preferably an extruded profile made of aluminum or an aluminum alloy; alternatively, other metal alloys, such as a magnesium alloy, can be used. Steel can also be used for the center piece. The same materials can also be used for the end pieces. In particular, the end pieces can be made of steel, steel hybrid, or any plastic that meets the mechanical requirements of a collision, as well as fiber-reinforced and / or particle-reinforced plastics, such as carbon fiber-reinforced plastic. The joining technology between the end pieces and the center piece must be selected accordingly to achieve a corrosion-free, strong, and permanent connection between the center piece and the end pieces.

[0022] To meet the mechanical requirements in the event of a collision, the end pieces are advantageously formed from a closed profile with respect to a cross-section through the longitudinal extension of the center piece. Additional ribs, webs, and other reinforcing elements can be provided. In the simplest case, an extruded aluminum profile is used for the end pieces, each of which can have a transverse web running along its extension direction. This cross-web extends along the extension direction of the end pieces and thus along the extension direction of the center piece, particularly in the interior of the hollow extruded profile.

[0023] Preferably, the center piece is designed so long that, when installed in a vehicle intended for it, it extends to the left and right of the vehicle center along a transverse direction up to a respective headlight area. From there, the end pieces then continue along a transverse direction of the vehicle with a lowered upper side, advantageously reaching a wheel center. This means that the connection between the center piece and the respective end piece is advantageously located in an area that is mechanically irrelevant in the event of a collision and does not negatively impact the rest of the structure. Furthermore, due to the smaller component size of the respective end piece, rework can therefore take place on smaller machines - this saves costs.

[0024] In the embodiment according to the invention, the respective end piece is partially inserted as an insert into a respective hollow end face of the middle piece.

[0025] In this case, the respective end piece is designed in a stepped manner, wherein an insert section of the respective end piece, which is inserted into the middle piece, has a first cross section which is introduced into a hollow cross section of the middle piece, and a free-standing section of the respective end piece, which extends the middle piece along its direction of extension, has a second cross section which is smaller than the first cross section due to a step-like course on the upper side of the respective end piece.

[0026] According to a further advantageous embodiment, a step of the respective end piece is arranged in the region of a plane of the respective end face of the middle piece.

[0027] In the embodiment according to the invention, the respective end piece has at least two hollow chambers extending in the longitudinal direction of the respective end piece and arranged one above the other, of which the upper one is provided in the insert section of the respective end piece and runs from the interior of the middle piece only to one of the front sides of the middle piece, so that the respective lower one of the hollow chambers has the lowered upper side of the respective end piece.

[0028] According to a further advantageous embodiment, the lower hollow chamber is divided by a transverse web which extends in the longitudinal direction of the respective end piece.

[0029] According to a further advantageous embodiment, at least one of the hollow chambers is filled with a supporting material or a hollow chamber structure.

[0030] The support material is preferably foam. This foam material can be a cured plastic foam. In the extrusion direction, crosspieces of varying wall thicknesses can also be added to the extension element. Perpendicular to the extrusion direction, the respective end piece can also be designed as a sandwich, for example, comprising a honeycomb core in the sense of a hollow-chamber structure.

[0031] According to a further advantageous embodiment, the respective end piece is fixedly arranged on the middle piece by at least one screw and / or at least one threaded bolt and / or at least one plug pin and / or at least one rivet and / or at least one welded connection and / or at least one adhesive connection and / or at least one soldered connection.

[0032] According to a further advantageous embodiment, the respective end piece is made of an extruded aluminum profile.

[0033] A further aspect of the invention relates to a vehicle with a flexible cross member as described above and below, comprising a first and a second headlight, in particular vertical headlights, wherein the respective headlight is arranged above a lowered upper side of the respective end piece.

[0034] The respective headlight can be arranged along a vertical direction above an end piece located in its area, so that the respective headlight is aligned along a vertical straight line above an end piece. However, it can also be provided that the headlight is only located in a horizontal plane above the lowered upper side of the end piece located on its side, so that the most important prerequisite of a possible horizontal movement of the end piece below the headlight in the event of a collision is enabled. The horizontal position of the headlight plays a subordinate role here; the decisive factor is the relationship of a height coordinate of an underside of the headlight in relation to the lowered upper side of the respective end piece.

[0035] Advantages and preferred developments of the proposed vehicle result from an analogous and analogous transfer of the statements made above in connection with the proposed bending cross member.

[0036] Further advantages, features, and details will become apparent from the following description, which – where appropriate with reference to the drawings – describes at least one embodiment in detail. Identical, similar, and / or functionally equivalent parts are provided with the same reference numerals.

[0037] They show: Fig. 1: A bending cross member according to an embodiment of the invention in perspective at its right end. Fig. 2: The end piece of the bending cross member of the Fig. 1 schematically from a side view. Fig. 3: A vehicle with a bending cross member according to an embodiment of the invention.

[0038] The representations in the figures are schematic and not to scale.

[0039] Fig. Figure 1 shows a flexible cross member for installation on the front of a vehicle. The view is from the front of the vehicle, or rather the front of the vehicle. The flexible cross member is shown in perspective with its right end; for the sake of simplicity, the left end is shown in the Fig. 1 is omitted. An end piece 3 is connected to the front side of the right end of a center piece 1 of the bending cross member. The center piece 1 is made of an extruded aluminum profile, and the end piece 3 at the right end is also made of an extruded aluminum profile. As explained above, a left end piece 3 is also provided at the left end of the center piece 1, but for the sake of simplicity, it is not shown in Fig. 1. The center piece 1 has a hollow cross-section into which the right end piece 3 is inserted. However, the insertion length is smaller than the extension length of the end piece 3: only an insert section 7 of the end piece 3 is inserted through the hollow cross-section at the front side of the center piece 1. If the length of the insert section 7 is subtracted from the total length in the extension direction of the end piece 3, the length of the free-standing section of the end piece 3 is obtained, which extends the length of the center piece 1 in the extension direction along a vehicle transverse axis. Fig. For clarity, in Figure 1, each edge of the end piece 3 that is naturally visible in the perspective view is sketched with a solid line; edges not visible in this view are shown in dashed lines. Accordingly, a lower rear edge of the end piece 3 is shown in dashed lines, as are the edges that are inserted into the middle piece 1 along the insert section 7. The end piece 3 and the middle piece 1 are fixed together by screws 9. The end piece 3 is also made of an extruded aluminum profile and has two or more hollow chambers. The uppermost of the hollow chambers is provided in the area of ​​the insert section 7, but is cut off outside to achieve a step to the lowered upper side 5. As shown in Fig. 1, the gradation leads to the

[0040] Cutting off the uppermost hollow chamber ensures that an upper side of the middle piece 1, when installed in a vehicle, lies higher above the ground than the lowered upper side 5 of the end piece 3. The lowered upper side 5 can therefore rotate or slide under a headlight if a collision occurs and a resulting force is applied to the vehicle from the front, i.e. transversely to the direction of extension of the bending cross member. The lower hollow chamber of the end piece 3 is also divided by a crosspiece which extends along the direction of extension of the end piece 3 and thus also in the direction of extension of the middle piece 1, so that the crosspiece divides the lower hollow chamber into an upper chamber section and a lower chamber section which run over the entire length of the end piece 3, in contrast to the upper hollow chamber which only runs over the length of the insert section 7 of the end piece 3.At least one of the hollow chambers or chamber sections can also be filled with a supporting material to form a sandwich structure, for example, foam material or a honeycomb core. The wall thickness of the end piece 3 can be roughly based on the wall thickness of the middle piece 1, but can be individually designed according to the mechanical requirements.

[0041] Fig. 2 shows the end piece 3 of the Fig. 1 schematically in more detail from a side view. Here, the gradation becomes apparent. An insert section 7 of the end piece 3, which at least partially fills the inner cross-section of the front side of the middle piece 1, has a significantly higher vertical diameter than the exposed section of the end piece 3. Due to the downward gradation, the upper side 5 is, as in Fig. 1 is lowered to allow greater design freedom regarding the arrangement of a headlight in the vehicle. Preferably, the length of the freestanding section with the lowered surface 5 of the end piece 3 is at least twice the length of the insert section 7.

[0042] Fig. Figure 3 shows a vehicle front end with a flexible cross member. The respective end pieces 3 are positioned on a left and right side below a left and right headlight, respectively, while both end pieces 3 are connected by a center piece 1. The multi-part design of the flexible cross member is particularly advantageously utilized in the vertical headlights described above, but can also be used as an example in the Fig. 3 can be used with conventional headlights.

Claims

[1] Bending cross member for arrangement on a vehicle front, wherein the bending cross member is designed in several parts and has a central piece (1) to which a respective end piece (3) is arranged at both ends, wherein the respective end piece (3) is fixedly arranged on the middle piece (1) and extends the middle piece (1) in its direction of extension by a predetermined length, wherein the respective end piece (3) has a lowered upper side (5) relative to the middle piece (1), wherein the respective end piece (3) is partially inserted as an insert into a respective hollow end face of the middle piece (1) and the respective end piece (3) is designed in a stepped manner, wherein an insert section (7) of the respective end piece (3), which is inserted into the middle piece (1), has a first cross-section which is introduced into a hollow cross-section of the middle piece (1), and a free-standing section of the respective end piece (3), which extends the middle piece (1) along its direction of extension, has a second cross-section which is smaller than the first cross-section due to a step-like course on the upper side (5) of the respective end piece (3), characterized by , that the respective end piece (3) has at least two hollow chambers extending in the longitudinal direction of the respective end piece (3) and arranged one above the other, of which the upper of the hollow chambers is provided in the insert section (7) of the respective end piece (3) and runs from the interior of the middle piece (1) only to one of the respective end faces of the middle piece (1), so that the respective lower of the hollow chambers has the lowered upper side (5) of the respective end piece (3). [2] Bending cross member according to claim 1, wherein a step of the respective end piece (3) is arranged in the region of a plane of the respective end face of the middle piece (1). [3] Bending cross member according to claim 2, wherein the respective lower of the hollow chambers is divided by a transverse web which extends in the longitudinal direction of the respective end piece (3). [4] Bending cross member according to one of claims 1 to 3, wherein at least one of the hollow chambers is filled by a support material or a hollow chamber structure. [5] Bending cross member according to one of the preceding claims, wherein the respective end piece (3) is fixedly arranged on the middle piece (1) by at least one screw (9) and / or at least one threaded bolt and / or at least one plug bolt and / or at least one rivet and / or at least one welded connection and / or at least one adhesive connection and / or at least one soldered connection. [6] Bending cross member according to one of the preceding claims, wherein the respective end piece (3) is made of an extruded aluminum profile. [7] Vehicle with a bending cross member according to one of the preceding claims, comprising a first and a second headlight, wherein the respective headlight is arranged above a lowered upper side (5) of the respective end piece (3).

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