Bumper crossmember

Abstract

The invention relates to a bumper crossmember (1) for a vehicle comprising − a support (2), the longitudinal axis of which extends in the vehicle transverse direction (y direction) and which is open in the driving direction (x direction) and comprises a chamber (8) enclosed by an upper limb (5), a lower limb (6), and a web (7) that connects the two limbs (5), (6) in the vehicle vertical direction, z direction, − a closing plate (3) which spans the support opening in the vehicle vertical direction (z direction) and which is connected to the limbs (5), (6) of the support (2), and − an insert (9), (9.1) which is arranged in the chamber (8) of the support (2) and has an upper limb (10), a lower limb (11), and a back (12) that connects the limbs (10), (11) at the rearward closure of the limbs, the open side of which faces in the driving direction (x direction), and the limbs (10), (11) of which are connected to the closing plate (3). The invention is characterized in particular in that the back (12) of the insert (9), (9.1) has a convex shape at least in the central section thereof, with respect to the longitudinal extension (y direction) of the back.

Description

[0001] bumper cross member

[0002] The invention relates to a bumper cross member for a vehicle with a support extending with its longitudinal axis in the vehicle transverse direction (y-direction), open in the direction of travel (x-direction) with a chamber enclosed by an upper leg, a lower leg and a web connecting the two legs in the vehicle vertical direction (z-direction), with a striker plate spanning the support opening in the vehicle vertical direction (z-direction) and connected to the legs of the support and with an insert arranged in the chamber of the support, having an upper leg, a lower leg and a back connecting the legs at their rear end, the open side of which points in the direction of travel (x-direction) and the legs of which are connected to the striker plate.

[0003] Bumper cross members are located at the front and / or rear of motor vehicles. Bumper cross members comprise a support profile that is typically hat-shaped in cross-section and attached to the vehicle. The profile is formed by an upper leg, a lower leg, and a web connecting the two legs at their longitudinal end facing the vehicle chassis. The support is open in the direction of travel and therefore has a chamber that is typically oval in cross-section and open in the direction of travel. The web connecting the legs faces the vehicle chassis. The support is attached to the vehicle side with the interposition of crash boxes. The two legs enclosing the support chamber have flanges at their ends that are folded away from the chamber in the vertical direction (y-direction). A locking plate is attached to these flanges to close the chamber at the front.The strike plate connected to the flanges of the legs also serves to stiffen the beam, as it provides a box profile along the length of the strike plate. This design prevents one or the other leg of the beam from shifting relative to the other in the event of an impact. In some designs, the strike plate extends over the entire or virtually entire length of the beam.

[0004] The deformation behavior and strength of such a bumper cross member are largely determined by the depth of the beam's profiling. The depth of a bumper cross member, and thus its extension in the vehicle's longitudinal direction (x-direction), is generally limited. This must be taken into account when dimensioning the beam's profiling depth in conjunction with the design of the bumper cross member. In some cases, however, this is not sufficient to provide the bumper cross member with the desired strength. To remedy this situation, WO 2016 / 163054 A1 proposes incorporating a stiffening element into the beam's chamber.The stiffening element known from this prior art is an open or closed stiffening element with a roughly trapezoidal cross-section, which is welded to the base of its shorter trapezoidal side with the web of the beam connecting the legs. In a design in which the stiffening element is open, it has legs that are folded outwards in a vertical direction and are integrated into the joint between the folded flanges of the beam's legs and the strike plate. The stiffening element is located centrally with respect to the beam and extends only over a short section relative to its longitudinal extent.

[0005] Even if the installation of such a stiffening element can improve the crash performance of the bumper cross member in the so-called pole test, disadvantages must still be accepted. These include, firstly, the necessary welding of the stiffening element to the web of the support profile, which is not without problems, especially if the stiffening element is closed and thus designed as a hollow chamber profile, due to the lack of or extremely difficult accessibility of the joint.

[0006] Another bumper cross member with an insert is known from WO 2019 / 072653 A1. This insert has a U-shaped profile and is connected to the striker plate by means of a weld seam along its entire length, with the end faces of its legs facing forward in the direction of travel. The back of this insert is straight along the insert's length and is positioned within the beam chamber at a distance from the beam. This insert stiffens the bumper cross member. An additional stiffening element is inserted in the center section of this insert.

[0007] US 2023 / 0143784 A1 discloses a bumper cross member. This comprises a support having a hat-shaped cross-sectional profile. Its open side facing forward in the vehicle direction is closed by a locking plate. In the exemplary embodiment described in Figure 9 of this prior art, the bumper cross member has an insert. This insert is also hat-shaped and has an upper leg and a lower leg, as well as a back connecting the two legs. This insert is connected by its straight back to the inside of the locking plate. The open side of the insert faces the vehicle chassis.

[0008] The aim of inserts such as those described above is to stiffen the bumper cross member, thus making it less susceptible to deformation. While on the one hand such a bumper cross member is intended to be stiffened by such an insert, it must also meet the usual test requirements, for example the MPDB test (Mobile Progressive Deformable Barrier) or the Pole test. The absorption of the impact force should occur not only via the crash boxes provided for this purpose, but also via deformation of the bumper cross member. Therefore, a bumper cross member must not be designed to be too stiff in those sections that are intended to deform, for example in an MPDB test. A problem with conventional bumper cross members is that after a certain amount of deformation, the side facing the vehicle chassis breaks open and can then no longer absorb energy.To counteract this, the supports and inserts are designed with appropriate wall thicknesses to prevent premature breakage. This is achieved at the expense of increased weight for the bumper cross member.

[0009] Based on this discussed prior art, the invention is therefore based on the object of improving a bumper cross member in which an insert is arranged in the chamber of the support, in such a way that it has an improved crash performance, in particular can absorb even higher deformation rates without cracks or breakage.

[0010] This object is achieved according to the invention by a bumper cross member of the generic type mentioned at the outset, in which the back of the insert is convexly shaped at least in its middle section, relative to its longitudinal extent (y-direction).

[0011] The directions used in this document are those typically used in motor vehicles. Thus, the x-direction is the longitudinal direction of the vehicle, the y-direction is the transverse direction (width direction), and the z-direction is the vertical axis.

[0012] In this bumper cross member, the back of the insert is bulged toward the vehicle chassis, at least in its central section. This provides a material specification so that, in an MPDB load case, greater deformation can be absorbed without cracking or breakage. The convex shape of the back of the insert, pointing away from the striker plate and extending in the direction of the insert's longitudinal extent, is thus already pre-formed in this bumper cross member in the direction of the deformation, so that a deformation system for absorbing forces in an MPDB load case is already specified. The tensile forces acting on the back in the event of required force absorption are correspondingly lower.This central section of the insert preferably extends over at least 25%, but typically no more than 70% to 80%, of the distance between the two crash boxes installed on the bumper cross member to connect it to the side members of a vehicle. This central section preferably occupies at least 35% to 40%, but no more than 60% to 70%, of the longitudinal extent of the insert.

[0013] In a preferred embodiment, the improved crash performance described above is supported by providing a transition section between the central section with its convex shape and the respective end sections of the insert, formed by changing the depth (x-direction) of the insert as a result of shaping the back. This transition section is concave in one embodiment, but can also have a convex shape. These transition sections in the back of the insert create a material reservoir, so that the insert can be stretched in these insert sections under the aforementioned load case without overloading occurring due to the tensile forces acting on the back.

[0014] The insert is typically located centrally with respect to the longitudinal extent of the beam in its chamber, which is open in the direction of travel. However, a different positioning is also possible, for example, if a different crash behavior is desired in relation to the width of the vehicle (longitudinal extent of the bumper cross member).

[0015] To further improve crash performance, i.e. bending of the bumper cross member in the x-direction, for example in an MPDB load case, the insert is only connected to the striker plate in individual sections that are spaced apart from one another in the longitudinal extension of the insert. The striker plate with the insert connected to it is located on the side of the obstacle and thus on the inside of a deformation of the bumper cross member. As a result of this measure, the sections located between the connecting sections where the insert is connected to the striker plate act as prepared bending or buckling points. The reason for this is the lack of the weld seams typically present for connecting the insert to the striker plate and the resulting weakening.This deformation behavior on the side of the bumper cross member facing the obstacle can be further supported by the insert not contacting the striker plate between its connection points, where it is connected to the striker plate, meaning that the leg ends facing the striker plate are spaced from the striker plate in these sections. Relative to the longitudinal extent of the insert, the sum of the extensions of the connection sections in this direction, with which the insert is connected to the striker plate, is less than the sum of the sections not connected to the striker plate, which, according to the preferred embodiment described above, are also spaced from the striker plate.

[0016] Thanks to the special design of the insert in this bumper cross member, it easily meets the crash performance requirements. The crash performance of the bumper cross member is significantly influenced by the design of the insert. Due to the special design of the insert, both the beam and the insert can be manufactured with relatively thinner walls. The same applies to the striker plate. The overall weight of the bumper cross member is correspondingly lower, despite the improved crash performance.

[0017] According to a preferred embodiment, the insert is arranged within the chamber of the support in such a way that it does not contact the support, thus maintaining a sufficient distance between the insert and the support. Should the bumper cross member be coated, for example, during dip painting, there are no gussets that might not be wetted.

[0018] To achieve the crash performance described above, or in addition to this, the insert can have differently designed insert sections in the direction of its longitudinal extent with regard to its height, its width, the final contour of the legs and / or its material thickness. In this way, the crash performance of the bumper cross member as well as its strength can be influenced simply by the appropriate design and selection of the insert to be installed in the chamber of a support held by the striking plate. This means that one and the same support and one and the same striking plate can be used for vehicles with different crash performance designs, whereby the bumper cross members formed from it with the respective insert differ only in a different design of their respective insert and / or in the design of the connecting sections of the insert to the striking plate.

[0019] Typically, the insert sections are designed to be mirror-symmetrical to the center of the insert. This can also be designed differently if uneven crash behavior is required across the width of the vehicle and thus the longitudinal extent of the bumper cross member.

[0020] The transitions from a first insert section to the adjacent insert section can be provided equally in both legs of the insert and also aligned with each other in the z-direction. However, it is also possible for such transitions to be designed differently in the upper leg than in the lower leg. This affects both the positioning of the transition and the degree of change.

[0021] In a preferred embodiment of such a bumper cross member, the insert is divided into several insert sections along its longitudinal extension. Such an insert can, for example, have a central section as the first insert section and each of its adjoining end sections with an interposed transition section. In a preferred embodiment, the transition section between the two end sections and the central section is tapered with respect to the cross-sectional area of ​​the insert, whereby such a taper can relate to both the height and / or the width of the insert.In the embodiment already described above, such a transition section is waisted by a concave design of the back, wherein in addition to further accentuating such a waist, the leg ends of the insert in the x-direction with the concave design of the back also have concave recesses.

[0022] With such a design of the bumper cross member, the end sections can also be further subdivided into individual sections, each provided by a transition section tapered in the direction of the depth of the insert (x-direction). Typically, such a bumper cross member then has a longer longitudinal extension and extends, for example, into the area where the crash boxes are connected to the bumper cross member. In one embodiment, the outer end sections of the insert overlap in the x-direction with the wall of a crash box facing the vehicle center.

[0023] Such a bumper cross member is typically connected to the striking plate by the legs of its two end sections and by the first section of the middle section. According to one embodiment, the sections of the insert located between these connecting sections are not connected to the striking plate and have a corresponding, typically concave, notch at the ends of their legs so that they do not contact the striking plate. According to another embodiment, the middle section is connected to the striking plate in its edge sections and additionally also in the middle of this central section. The number and length of the respective connections or joints between the insert and the striking plate, typically brought about by fusion joining or welding, influence the crash performance.Therefore, this can also be used to design the crash performance of the bumper cross member.

[0024] As a further measure, which can be used in addition to or instead of the measures described above to improve the crash performance of the bumper cross member, it is provided for this to have buckling support structures. This means that the insert, the support and / or the striker plate each have one or more buckling support structures. These buckling support structures serve the purpose of ensuring that, in the event of energy absorption, for example during a pole test, the bumper cross member buckles at predetermined, defined points, namely where the buckling support structures are arranged. This allows the bumper cross member to better conform to the contour of the obstacle, for example the pole. The bumper cross member typically has several such buckling support structures.In such a case, they are arranged mirror-symmetrically to the center of the bumper cross member and thus mirror-symmetrically to the center of the respective component, relative to its longitudinal extent, which is equipped with such buckling support structures. Preferably, such buckling support structures are not caused by a weakened material, but rather by a corresponding embossing, typically in the form of a bead and / or a notch. Depending on the design of the desired buckling behavior of the bumper cross member, the insert, the support, and / or the striker plate can each have a buckling support structure in an aligned position in the x-direction.

[0025] In one embodiment, the ends of the insert's legs pointing in the beam opening direction have a buckling support bead, preferably designed as a positive structure. Such a bead is open in the direction of the beam opening and typically has its maximum extent at the leg end. This typically tapers off toward the back of the insert before the transition into the back. To achieve uniform buckling behavior in both legs of the insert, both legs of the insert typically carry buckling support structures aligned with one another in the vertical direction (z-direction) of the insert.

[0026] Similarly, the leg ends of the support can be equipped with one or more buckling support beads. In a preferred embodiment, the support has such a buckling support bead only centrally in both legs with respect to its longitudinal extent. At other positions, the support has notches as buckling support structures. A combination of a buckling support bead with a notch or recess is also possible. A notch can be provided at the free end of the legs, for example, to accommodate a buckling support bead of the strike plate.

[0027] The striking plate can also be equipped with such buckling support structures. These are typically negative structures, i.e., buckling support beads extending in the z-direction, which are pronounced toward the support. The buckling behavior can be influenced by the length of these buckling support beads. Preferably, these beads of the striking plate do not extend across its entire height. With such a design, buckling support structures located between the legs of the support can be distinguished from those that engage the leg ends of the support.

[0028] The above-described equipment of such a bumper cross member is particularly effective in conjunction with the previously described design, in which the insert's legs are only partially connected to the striker plate. With such a design, the striker plate is not connected to the insert's legs in the area of ​​the buckling system structures.

[0029] The support of such a bumper cross member is typically a hat profile. This can be made from a single steel plate. In such a case, it is advisable to also manufacture the striker plate and insert from sheet steel plates, as these components of the bumper cross member can then be easily fused together by welding.

[0030] In the case of the stressed bumper cross member, the crash performance can be optimized in a variety of ways by designing its insert or adapting it to the respective requirements, for example, so that in a pole test the deformed bumper cross member adheres to the outer surface of the pole without cracks or breakage.

[0031] With regard to the bumper cross member according to the invention, it should also be emphasized that, due to the connection of the insert to the striker plate, this connection remains intact even if the bumper cross member breaks on the side facing the vehicle chassis due to excessive force, for example, during a pole test. Fracture on the side of the bumper cross member facing away from the vehicle chassis is prevented by the connection of the insert.

[0032] The invention is described below using exemplary embodiments with reference to the accompanying figures. They show:

[0033] Fig. 1: a three-dimensional representation of a bumper cross member according to the invention, in which the front locking plate is shown transparent to allow the insert located therein to be seen.

[0034] Fig. 2: the insert of the bumper cross member of Figure 1 in a perspective view,

[0035] Fig. 3: a longitudinal section in the xy plane through the

[0036] Bumper cross member of Figure 1 ,

[0037] Fig. 4: another bumper cross member according to the invention, which differs from that of Figure 3 by using a different insert,

[0038] Fig. 5: the bumper cross member of Figure 4 moving towards an obstacle,

[0039] Fig. 6: the bumper cross member of Figure 5 deformed by the obstacle, Fig. 7: a representation corresponding to that of Figure 6, but with a cross member according to the prior art,

[0040] Fig. 8: a perspective view of another bumper cross member according to the invention,

[0041] Fig. 9: the bumper cross member of Figure 8, in which the locking plate is partially removed to obtain an insight into the support, with a first insert,

[0042] Fig. 10: the bumper cross member of Figure 8, with the locking plate partially removed to provide a view into the beam, with an alternative insert,

[0043] Fig. 11 : a perspective view of the insert of the bumper cross member of Figure 9,

[0044] Fig. 12: a front view of the insert of Figure 1 1 ,

[0045] Fig. 13: a perspective view of the insert of the bumper cross member of Figure 10,

[0046] Fig. 14: a front view of the insert of Figure 13,

[0047] Fig. 15: a longitudinal section in the xy plane through the

[0048] Bumper cross member of Figure 9,

[0049] Fig. 16: a longitudinal section in the xy plane through the

[0050] Bumper cross member of Figure 10,

[0051] Fig. 17a-17c: Representations for visualizing the buckling behavior of the bumper cross member of Figure 9 during a pole test, wherein Figure 17a shows a first deformation, Figure 17b shows further deformation with deeper penetration of the obstacle, and Figure 17c shows the final deformation of the bumper cross member during the pole test. A bumper cross member 1 for a motor vehicle comprises a support 2. The support 2 is a U-shaped profile made from a sheet steel blank. In an embodiment not shown in the figures, the support 2 is designed as a hat profile. The support 2 extends over the entire longitudinal extent of the bumper cross member 1. The open side of the support 2 points forward in the direction of travel (x-direction). At the front, the support 2 is closed by a locking plate 3 in a manner known per se.Two crash boxes 4, 4.1 are connected to the rear side of the support 2, facing the vehicle chassis, spaced apart from each other. The bumper cross member 1 is attached to the chassis side via these.

[0052] The profile of the support 2 is provided by an upper leg 5, a lower leg 6, and a web 7 connecting the two legs 5, 6 along their longitudinal side facing the chassis. The two legs 5, 6 and the web 7 enclose a chamber 8. This chamber is closed at the front by the strike plate 3. The support 2 with the strike plate 3 thus forms a hollow chamber profile.

[0053] An insert 9 is arranged within the chamber 8. The insert 9 is also U-shaped. Its open side, like that of the support 2, faces in the direction of travel (x-direction). The insert is connected by welded joints to the side of the strike plate 3 facing the chamber 8 by sections of the end faces of its legs 10, 11.

[0054] The design of the insert 9 is explained below using the perspective view in Figure 2. The two legs 10, 11 are connected to one another at their rear, longitudinal end by a spine 12. In contrast to previously known inserts of this type, the spine 12 is not straight, but in the illustrated embodiment is characterized by straight sections at the ends, an adjoining concave section, and a central section that is convex in the direction of the web 7 of the support 2. The legs 10, 11 also do not run uniformly over the longitudinal extent of the insert 9. Their width changes over the longitudinal extent of the insert 9. The spine 12 is not only non-uniform in terms of its longitudinal extension over its longitudinal extent, but also varies in terms of its height (extension in the z-direction).In a central section, the height of the insert 9 is lower than in the sections adjacent to it on both sides.

[0055] The structural subdivision of the insert 9 is more clearly visible in the longitudinal section of Figure 3. The insert 9 comprises a central section 13. This section is the section in which the back 12 is convexly shaped in the direction of the vehicle chassis and is thus bulged. The central section 13 merges into a transition section 14, 14.1, which in turn is followed by an end section 15. The back 12 of the illustrated embodiment is straight in the region of its end sections 15, 15.1 and runs parallel or approximately parallel to the web 7 of the support 2 in these sections. In the transition sections 14, 14.1 the insert 9 is waisted, whereby its cross-sectional area is significantly reduced, namely to approximately 50% in the illustrated embodiment. The waist is achieved by a concave shape of the back 12 in the transition sections 14, 14.1 and a likewise concave shape of the leg ends pointing towards the striking plate 3 (visible in Figure 3 by the lower leg 11). The leg ends of the insert 9 pointing towards the striking plate 3 are also contoured in the central section 13 in such a way that they do not rest against the inside of the striking plate 3 over their entire extent. In the illustrated embodiment, the leg ends rest against the inside of the striking plate 3 in three sections of the central section 13. In these sections, also referred to as connecting sections 16, the leg ends of the legs 10, 11 are connected to the inside of the striking plate 3 by means of a weld seam. The connecting sections 16 are arranged at a distance from one another in the direction of the longitudinal extent of the insert 9. The leg ends of the insert 9 between the connecting sections 16, however, do not contact the inside of the insert 3.These sections are also concavely shaped, whereby the leg ends are spaced from the inside of the striking plate 3. In addition to the connection points 13 of the central section 6, the insert 9 is also connected to the striking plate 3 by welding via the leg ends of the end sections 15, 15.1.

[0056] As can be seen from Figure 2, the central section 13 is additionally structured in that the middle area of ​​the central section 13 has a lower back height than in the adjacent sections.

[0057] Figure 4 shows a longitudinal section through a bumper cross member 1.1 which, with the exception of the contouring of the leg ends of its insert 9.1, corresponds to the bumper cross member 1 of the preceding figures. In this respect, the statements regarding the bumper cross member 1 apply equally to the bumper cross member 1.1. The insert 9.1 has only two connection points 16.1 in its central section 13.1. The third connection point 16 located between the two outer connection points 16 of the insert 9 is not provided for the insert 9.1. In this exemplary embodiment, the entire intermediate piece between the two connection points 16.1 is not in contact with the inside of the striking plate 3 and is concave over this length.

[0058] The above-mentioned bumper cross members 1, 1.1 are significantly improved in terms of their crash performance compared to conventional bumpers in which inserts are inserted into the member but which do not have the structure of the inserts 9 or 9.1.

[0059] Figure 5 shows the bumper cross member 1 in a representation corresponding to that of Figure 3 in front of an obstacle H. The bumper cross member 1 moves in the x-direction towards the obstacle H. The special design of the insert 9 causes the bumper cross member 1 to wrap around the obstacle H, but without cracking or even breaking. The reason for this is the special design of the insert 9, which provides a curvature or deformation facility on the tensile side (the side facing the vehicle chassis) due to the convex design of its central section 13 and the material specification present in the transition sections 14, 14.1 as a result of the convex shape. For this reason, the back 12 of the insert 10 can absorb or withstand significantly higher tensile forces than conventional bumper cross members.

[0060] Figure 6 shows the bumper cross member 1 after a deformation of approximately 260 mm, which was absorbed without cracks by deforming the bumper cross member 1, as shown in Figure 6. The concave recesses on the strike plate-side pressure side serve as predefined bending or kinking points.

[0061] For comparison, Figure 7 shows a bumper cross member 17 with a conventional insert 18, which has the same cross-sectional geometry over its entire longitudinal extent. This illustration clearly shows that the bumper cross member 17 broke at the same amount of deformation that the bumper cross member 1 in Figure 6 easily absorbed.

[0062] The measures described significantly increase the crash performance of the bumper cross member according to the invention, specifically by approximately 30% to 40% in the illustrated embodiment. Compared to the bumper cross member 17 according to the prior art, the bumper cross member 1 weighs 2.5 kg, generally approximately 20% to 30% less. The energy absorbed during the deformation shown is approximately 2.6 kJ / kg. For the bumper cross member 17, as shown in Figure 7, only 2.0 kJ / kg can be absorbed. The lower mass and higher energy absorption result in the significantly increased efficiency.

[0063] Figure 8 shows a further bumper cross member 20 which is basically constructed like the previously described bumper cross members 1 and 1.1. In this respect, the relevant statements apply equally to the bumper cross member 20. Only the distinguishing features will be discussed below. Compared to the bumper cross members 1 and 1.1, the bumper cross member 20 differs in that it also has a number of buckling support structures. In the illustrated embodiment, both the striker plate 21 and its insert 22 (see Figure 9) as well as its support 23 have such structures. The buckling support structures are structural developments of the bumper cross member 20 which cause it to buckle in the event of energy absorption, for example during a pole test, in the positions of these structures and thus ensure that it nestles or bends.To improve the fit of the bumper cross member to the contour of the pole.

[0064] The support 23 of the illustrated embodiment has two differently designed buckling support structures. Firstly, the support 23 has a buckling support bead 24 in each of its two legs, centered along its longitudinal extent, which defines the front ends of the legs. Secondly, the support 25 has notches as buckling support structures.

[0065] The striking plate 21 also carries the buckling support structures shown in the exemplary embodiment, which are arranged mirror-symmetrically to the center, relative to the longitudinal extent of the striking plate 21. These buckling support structures are buckling support beads extending in the vertical direction, the embossing direction of which is executed around the support 23. In the center of the striking plate 21, there are two buckling support beads 24.1 extending in the vertical direction, forming the top and bottom ends. At a longitudinal axial distance from these, adjacent to these individual beads, which are cut off towards the free end of the striking plate 21, there is one buckling support bead each arranged in the central section, relative to the vertical direction of the striking plate 21.Again spaced apart from these, at the position where the notches 25 are arranged in the support 23, are vertically extending buckling support beads, which are again cut off at the ends. None of the buckling support beads of the striking plate 21 extends over the entire height of the striking plate 21.

[0066] The insert 22 shown in isolation in Figure 11, like the previously described inserts 13, 13.1, comprises a central section and two transition sections connected to the respective ends, each followed by an end section. The transition section of the insert 22 is designed to be tapered with regard to its back design and the design of the free ends of its legs, as described for the insert 13 or 13.1. In addition, the insert 22 has buckling support beads 26, 26.1, with each leg of the insert 22 carrying two buckling support beads 26 or 26.1 arranged at a longitudinal axial distance from one another. The buckling support beads 26, 26.1 are arranged mirror-symmetrically to the center of the insert 22, based on its longitudinal extent. The buckling beads 26, 26.1 are designed as positive structures and thus extend outwards from the insert 22 with respect to their embossing direction in the z-direction.The bending guide beads 26, 26.1 have their greatest embossing depth at the respective leg end. The bending guide beads 26, 26.1 taper toward the spine of the insert 22 and end before the transition from the legs to the spine. As can be seen from Figure 12, the bending guide beads 26, 26.1 are arranged in alignment with each other in the z-direction in the two legs.

[0067] From the front view of the insert 22 in Figure 12 it is also clear that the central section in the z-direction is reduced in the region of its middle section in the vertical direction (z-direction) compared to the adjacent sections of the central section.

[0068] Figure 10 shows another bumper cross member 20.1, in which the locking plate 21.1 has been removed in half to provide a view of its support 23.1. The bumper cross member 20.1 differs from the bumper cross member 20 only in its insert 22.1, which has a greater longitudinal extension than the insert 22 of the bumper cross member 20. In this bumper cross member, the support 23.1 and the locking plate 21.1 are identical components to those of the bumper cross member 20.

[0069] The insert 22.1 of the bumper cross member 20.1 is shown in Figure 13 in a perspective view. This is ultimately identical to the insert 22, so that the relevant statements apply equally to the insert 22.1. The insert 22.1 differs from the insert 22 only by an extension of its end sections 27, which in turn are divided into two sections 28, 28.1. A first section 28 of the end section 27 borders the transition section between the central section and the end section 27. A further section 28.1 of this end section 22 is in turn spaced from the outermost, shorter end section 28.1 by a transition section 29. The transition section 29 between the two sections 28,

[0070] 28.1 of an end section 27 is constructed in the same way as the transition section between the end section 27 and the central section with regard to the contouring of the spine and the trimming of the legs. The opposing end sections 27 of the insert 22.1 are constructed identically.

[0071] Figure 15 shows the bumper cross member 20 in a longitudinal section. The convex shape in its central section, pointing toward the rear web of the support 23 in the direction of the longitudinal extension of the insert 22, is clearly visible. Also visible in this illustration are the buckling support beads 26.1. The apex of the buckling support beads

[0072] 26.1 is set back from the end of the leg facing the striking plate 21, so that in the central region of the buckling contact beads 26.1, they do not rest against the striking plate 21. Thus, the buckling contact structure provided by the buckling contact beads 26.1 is additionally determined by this material recess. The same applies to the buckling contact beads 26 of the other leg of the insert 22. The insert 22 is connected to the striking plate 21 by a welded joint at the connecting sections designated by reference numeral 30.

[0073] Figure 16 shows the bumper cross member 20.1 in the same representation as Figure 15 shows the bumper cross member 20. The above statements regarding the bumper cross member 20 apply equally to the bumper cross member 21. Due to the greater length of the insert 22.1, this is in addition to the connecting sections 30.1, to which the insert

[0074] 22.1 is connected to the striking plate 21.1 at the same points as the insert 22 of the bumper cross member 20, and is additionally connected to the striking plate 21.1 at its outer end sections 28.1. These sections 28.1 therefore also provide a connecting section 30.1 with the front end of their legs. The sequence of figures 17a to 17c visualizes the deformation behavior of the bumper cross member 20 during a pole test. Figure 17a shows an initial deformation of the bumper cross member 20 in the region of its center. The buckling behavior is defined by the buckling system structures located in the central section of the bumper cross member 20. If the pole penetrates further into the bumper cross member 20 towards the vehicle, this central section deforms further. In addition, kinks occur at the transition sections between the central section and the end sections, as can be seen in Figure 17b.Figure 17c shows the bumper cross member 20, which is nestled against the pole 31 (pole) with a very uniform contour. The particularly uniform nestling or placement of the bumper cross member 20 against the obstacle, which in this case is the pole 31, can be seen.

[0075] List of reference symbols

[0076] 1. 1.1 Bumper cross member

[0077] 2 carriers

[0078] 3 strike plate

[0079] 4. 4.1 Crash box

[0080] 5 legs

[0081] 6 legs

[0082] 7 jetty

[0083] 8 chamber

[0084] 9. 9.1 Insert

[0085] 10 legs

[0086] 11 legs

[0087] 12 Back . 13.1 Central section , 14.1 Transition section . 15.1 End section . 16.1 Connection section

[0088] 17 bumper cross members (state of the art)

[0089] 18 Inserts (state of the art) . 20.1 Bumper cross member . 21.1 Striker plate . 22.1 Insert . 23.1 Support . 24.1 Kick-back groove

[0090] 25 Notch . 26.1 Buckling bead

[0091] 27 Final section . 28.1 Section

[0092] 29 Transition section . 30.1 Connection section

[0093] 31 Post

Claims

Patent claims 1. Bumper cross member for a vehicle - with a support (2, 23, 23.1) extending with its longitudinal axis in the transverse direction of the vehicle (y-direction) and open in the direction of travel (x-direction) with a chamber (8) enclosed by an upper leg (5), a lower leg (6) and a web (7) connecting the two legs (5, 6) in the vertical direction of the vehicle (z-direction), - with a locking plate (3, 21, 21.1) spanning the support opening in the vehicle vertical direction (z-direction) and connected to the legs (5, 6) of the support (2, 23.1) and - with an insert (9, 9.1, 22, 22.1) arranged in the chamber (8) of the carrier (2), having an upper leg (10), a lower leg (11) and a back (12) connecting the legs (10, 11) at their rear end, the open side of which points in the direction of travel (x-direction) and the legs (10, 11) of which are connected to the striking plate (3, 21, 21.1), characterized in that the back (12) of the insert (9, 9.1, 22, 22.1) is convex at least in its central section, based on its longitudinal extent (y-direction).

2. Bumper cross member according to claim 1, characterized in that the insert (9, 9.1) is arranged centrally with respect to the longitudinal extent of the support (2, 23, 23.1) in the chamber (8) of the support (2, 23, 23.1).

3. Bumper cross member according to claim 1 or 2, characterized in that the insert (9, 9.1, 22, 22.1) is connected to the striker plate (3, 21, 21.1) with its legs (10, 11) only in individual sections spaced apart from one another in the direction of its longitudinal extent.

4. Bumper cross member according to claim 3, characterized in that the legs (10, 11) of the insert (9, 9.1, 22, 22.1) are only in those sections in which they are connected to the locking plate (3, 21, 21 .1 ) are connected, reach up to the striking plate (3, 21 , 21 .1 ) and are spaced from the striking plate (3, 21 , 21 .1 ) in the intermediate sections.

5. Bumper cross member according to one of claims 1 to 4, characterized in that the insert (9, 9.1, 22, 22.1) is arranged within the chamber (8) of the support (2, 23, 23.1) at a distance from its legs (5, 6) and its web (7).

6. Bumper cross member according to one of claims 1 to 5, characterized in that the insert (9, 9.1, 22, 22.1) has insert sections (13, 14, 14.1, 15, 15.1; 13.1 ).

7. Bumper cross member according to claim 6, characterized in that the transitions from the legs (10, 11) of a first insert section to an adjacent second insert section are designed differently.

8. Bumper cross member according to claim 6 or 7, characterized in that the insert (9, 9.1, 22, 22.1) has a central section (13) and an end section (15, 15.1, 27) as insert sections, wherein the end sections (15, 15.1, 27) are separated from the central section (13) by a transition section (14, 14.1) as a further insert section with a concave contouring of the back (12).

9. Bumper cross member according to claim 8, characterized in that the end sections (27) of the insert (22, 22.1) have two sections (28, 28.1) separated by a concave back section as a transition section (29).

10. Bumper cross member according to claim 8 or 9, characterized in that in the transition section(s) (14, 14.1, 29) the ends of the legs (5, 6) of the insert (9, 9.1, 22, 22.1) also have a concave contour.

11. Bumper cross member according to claim 9 or 10, characterized in that the legs of the end sections (15, 15.1, 27) and those of the respective first section of the central section (13, 13.1) are connected to the locking plate (3, 21, 21.1).

12. Bumper cross member according to claim 1 1, characterized in that the insert (9) is additionally connected to the locking plate (3) by its legs in the middle of its central section (13).

13. Bumper cross member according to claim 1 1 or 12, characterized in that those sections with which the insert (9, 9.1, 22, 22.1) is connected with its legs to the striker plate (3, 21, 21.1) are the only connection points (16, 16.1) of the insert (9, 9.1, 22, 22.1) to the striker plate (3, 21, 21.1).

14. Bumper cross member according to one of claims 1 to 13, characterized in that the insert (21, 21.1), the support (23, 23.1) and / or the striker plate (21, 21.1) have one or more buckling support structures.

15. Bumper cross member according to claim 14, characterized in that the insert (22, 22.1), the support (23, 23.1) and / or the closing plate (21, 21.1) have a plurality of buckling support structures arranged mirror-symmetrically to the center of the respective component with respect to its longitudinal extent.

16. Bumper cross member according to claim 14 or 15, characterized in that the ends of the legs of the insert (22, 22.1) pointing in the direction of the carrier opening have at least one, in particular as Positive structure designed buckling support bead (26, 26.1) as a buckling support structure, wherein the buckling support structures of the two legs are preferably arranged in alignment with one another in the vertical direction of the insert (22, 22.1).

17. Bumper cross member according to claim 16, characterized in that the at least one buckling bead (26, 26.1) of a leg of the insert (22, 22.1) is designed as a bead ending before the transition of the leg into the back of the insert (22, 22.1) with its maximum expression at the front leg end.

18. Bumper cross member according to one of claims 14 to 17, characterized in that the legs of the support (23, 23.1) have a buckling bead (24) centrally in relation to its longitudinal extent, in particular designed as a positive structure.

19. Bumper cross member according to one of claims 14 to 18, characterized in that at least one notch (25) is introduced into the front end of at least one of the legs of the support (23, 23.1).

20. Bumper cross member according to one of claims 1 to 19, characterized in that the locking plate (21, 21.1) has at least one buckling support bead (24.1) extending in the vertical direction and designed as a negative structure as a buckling support structure.

21. Bumper cross member according to claim 20, characterized in that the locking plate (21, 21.1) has a plurality of vertically extending buckling beads (24.1) arranged at a distance from one another in its longitudinal extent, in a mirror-symmetrical arrangement to the center of the locking plate (21, 21.1) with respect to its longitudinal extent.

22. Bumper cross member according to claim 20 or 21, characterized in that the locking plate (21, 21.1) is arranged centrally with respect to its Longitudinal extension has a buckling bead (24.1) in its upper and lower ends.

23. Bumper cross member according to one of claims 1 to 22, characterized in that the support (2, 23, 23.1), the locking plate (3, 21 , 21.1 ) and the insert (9, 9.1 , 22, 22.1 ) are parts made of sheet steel plates.

24. Bumper cross member according to one of claims 1 to 23, characterized in that the insert (9, 9.1, 22, 22.1) is connected to the locking plate (3, 21, 21.1) and the locking plate (3, 21, 21.1) is connected to the legs (5, 6) of the support (2, 23, 23.1) by fusion joints.

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