Bumper cross beam for a motor vehicle and method for producing a bumper cross beam

Abstract

What is disclosed is a bumper cross beam (1) for a motor vehicle, having a profiled cross section which can absorb a bending moment and has an outwardly facing vertical projection (2) which absorbs a crash force on the force application side. A particular characteristic feature is that disposed on the force application side of the vertical projection (2) is at least one material-thickening reinforcing rib (12, 13, 14) which protrudes from the vertical projection (2) in the direction of the introduced crash force F, runs in the direction of longitudinal extent of the bumper cross beam (1) and is weakened locally along its profile in the direction of longitudinal extent of the bumper cross beam (1) by a reduction in material.

Description

[0001] Bumper cross member for a motor vehicle and method for producing a bumper cross member

[0002] The invention relates to a bumper cross member for a motor vehicle having the features of the preamble of claim 1 and a method for producing a bumper cross member according to the features of patent claim 14.

[0003] In the event of a frontal collision, a bumper cross member in a motor vehicle serves to protect the components behind it as well as the passenger compartment in the event of a crash along the longitudinal axis of the vehicle, such as a frontal or rear-end collision. The bumper cross member extends transversely to the vehicle's direction of travel and is positioned in front of the components to be protected. The longitudinal extent of the bumper cross member follows the transverse direction of the vehicle. At its lateral end areas, the bumper cross member is connected to a longitudinal member component of the vehicle, typically a crash box. In the event of a crash, a bumper cross member is therefore subjected to significant bending stress.

[0004] Against this background, a bumper cross member has a profiled cross-section that can absorb bending moments. This can be, for example, a shell open on one side, comprising two legs and a web connecting the legs. Bumper cross members are also known that consist of a shell and a locking plate that closes the opening in the shell. Bumper cross members are also known that are designed as a hollow chamber profile, manufactured, for example, using an extrusion process.

[0005] The vertical web of the cross-section pointing in the direction of force application is subject to particular stress in the event of a crash due to the impact of the crash force. Its task is to distribute the force directly applied to it as evenly as possible across the cross-section. Depending on the design of the bumper cross member for the front or rear area, this vertical web refers to the forward-facing or rearward-facing vertical web of the bumper cross member with respect to the vehicle direction. EP 0 718 157 B1, JP 2014-121 955 A, JP 2012-62 012 A, JP H03-224 851 A, and JP 2007-153 108 A disclose bumpers or body structures for a vehicle.

[0006] The goal of vehicle design is to use the lightest materials possible. At the same time, a wide variety of variants is required, which necessitates the customization of individual structural components. Particularly in the context of electromobility and the associated changes in vehicle design, a further goal is to maximize the possible intrusion path until the bumper cross member ruptures in the event of a crash.

[0007] The object of the invention is to propose a bumper cross member and a corresponding manufacturing method whose performance is improved in one or more of the above objectives compared to the prior art.

[0008] The product-related part of the above-mentioned problem is solved by a generic bumper cross member as mentioned above with the features of claim 1. The process-related part of the above-mentioned problem is solved by a manufacturing method according to claim 14.

[0009] Advantageous embodiments emerge from the dependent claims and the description.

[0010] According to the invention, at least one stiffening rib is arranged on the outward-facing vertical web that absorbs a crash force on the force application side. The stiffening rib protrudes from the vertical web in the direction of the applied crash force and runs essentially in the longitudinal direction of the bumper cross member and thus essentially in the y-direction relative to the motor vehicle along the bumper cross member.

[0011] The vertical bar is provided with additional material through the reinforcement rib, preferably made of the same material as the vertical bar. The stiffening rib is therefore an addition to the existing vertical bar. The side of the vertical bar facing away from the crash force is thus essentially flat in the area of ​​the stiffening rib and not curved in the direction of the crash force like a bead. The vertical bar thus forms a basic structure on which the stiffening rib is arranged. The stiffening rib is part of the cross-section of the bumper cross member that absorbs the bending moment, thus significantly improving crash performance.

[0012] Advantageously, this design of the stiffening rib, as an addition to the vertical web as the basic structure, allows it to be locally weakened in predetermined sections by reducing the material to further improve crash performance. The material reduction occurs along the course of the stiffening rib in the longitudinal direction of the bumper cross member. The material reduction locally influences the area moment of inertia in the cross section, namely, it reduces it with respect to the crash force to be absorbed, so that the overall crash behavior can be actively influenced. For this purpose, a material reduction over a short section, approximately 3 to 5 cm along the longitudinal extension of the bumper cross member, is sufficient.

[0013] Such material weakening can serve to reduce stress peaks in the bumper cross member. For this purpose, a material reduction is provided in particular in the area where the bumper cross member connects to the vehicle's side members, such as the crash boxes. Especially with large intrusion paths, there is a risk of the bumper cross member cracking in the area where it connects to the vehicle's side members. Additional stiffening elements, such as a towing sleeve, can also be incorporated into the bumper cross member. Due to the connection to the side member section or the towing sleeve, the bumper cross member is already stiffened by other elements. Additional stiffening by means of the stiffening rib can lead to premature failure of the bumper cross member. The local material reduction in the connection area evens out these stress peaks and distributes them evenly into the material, thus counteracting cracking.For this purpose, a material reduction is planned over a section that extends beyond the connection to the longitudinal member or the crash box. The material reduction extends beyond the connection to the longitudinal member.

[0014] In another embodiment, the stiffening rib in the center region of the bumper cross member can be made of reduced material, particularly in at least two regions arranged symmetrically to the center of the bumper cross member. The center of the bumper cross member is defined as the center in the longitudinal direction of the bumper cross member, pointing in the vertical direction of the vehicle. Here, the material reduction serves to create predetermined buckling points that enable a specific deformation during specified tests, such as a pile test. The predetermined buckling points also enable stress peaks in the material, particularly on the side of the bumper cross member facing away from the load, by reducing the section moment in the reduced material area.Typically, the area of ​​material reduction for such behavior is relatively short, at least shorter than a material reduction in the area where the bumper cross member is connected to a longitudinal member.

[0015] The bead-shaped stiffening rib is preferably straight in its contour, pointing in the direction of load. This provides a flat force introduction surface. Although a completely rounded end face pointing in the direction of load would be conceivable, a straight force introduction surface avoids point loading. In its cross-section, the stiffening rib is then essentially rectangular or cuboid-shaped. It typically protrudes approximately 1 to 2 cm from the vertical web in the direction of load.

[0016] Preferably, the stiffening rib has a substantially consistent offset height relative to the vertical web along its path following the longitudinal extension of the bumper cross member. A deviation from this offset height is considered a material reduction. Due to the uniform offset height, the area moment of inertia of the bumper cross member is constant, at least with respect to the stiffening rib, along the path of the bumper cross member. A material reduction over a short section is only provided in the sections where the area moment of inertia is to be adjusted locally and specifically.

[0017] In one embodiment, the stiffening rib can be formed from solid material. This allows for free geometry creation or material reduction, particularly with regard to any curves leading into the material reduction to reduce stress concentrations.

[0018] In another embodiment, the stiffening rib can be designed as a hollow chamber. In this case, its load-removing wall is formed by the force-applying vertical web of the profiled cross-section, which forms the basic structure. The stiffening rib, designed as a hollow chamber, is thus self-contained, so that the bumper cross member, particularly with regard to the vertical web, remains closed at least with regard to the force-applying vertical web, despite the material reduction.

[0019] In particular, it is advantageously possible to provide for the material reduction of the stiffening rib to be achieved by machining. A bumper cross member is machined anyway as part of the manufacturing process, for example, to create holes for the towing sleeve or to provide connection points for a possible crash box or the longitudinal members of the vehicle. Against this background, the material reduction can also advantageously be achieved by machining. This results in considerable freedom in the design of the material reduction itself and also with regard to its intended position along the course of the bumper cross member. This allows for different variants to be developed without having to provide new tools for each one.The machining also creates an open fiber path in the area of ​​the material reduction, which has a positive effect on the possibility of targeted adjustment and deliberate disturbance of the area moment of inertia in the area of ​​the material reduction. The material reduction can be designed such that, in the direction of the stiffening rib, the transition to the material reduction of the stiffening rib is concavely curved in order to reduce a notch effect from the material-reduced area to the area at the front of the stiffening rib. The curvature preferably has a radius of at least half, preferably the entire projection height of the stiffening rib from the vertical web on the force application side. It can also be provided that the material reduction is angular towards the crash side, facing the front of the stiffening rib.This simplifies the manufacturing process, particularly during machining: To provide the material reduction, a milling drum plunges essentially vertically into the stiffening rib and forms the material reduction within the stiffening rib on any rounded curve, roughly corresponding to its diameter. The transition from the material reduction to the stiffening rib in its initial state is rounded by the geometry of the milling drum. The transition can also be angled or elliptical. In this case, a transition as flat as possible is provided, for example, in the case of an angled design at an angle of approximately 30 degrees, in order to reduce the stresses in the material-reduced area gradually rather than suddenly.

[0020] It can also be provided that the area where the stiffening rib is reduced in material is flush with the material of the vertical web surrounding the stiffening rib and facing in the direction of load. The stiffening rib is thus completely removed in the reduced-material area, leaving only the basic structure provided by the vertical web. This relieves the load on the area of ​​reduced material in that, in the vertical direction of the bumper cross member when mounted on a motor vehicle, essentially no additional stress concentrations can be observed in the reduced-material area, thus reducing stress peaks.

[0021] Preferably, the vertical web on the force application side has several stiffening ribs, for example, in the upper or lower region, in particular in its end region or centrally relative to its vertical direction. The several stiffening ribs can be designed differently not only in themselves, but also, in particular, with regard to the intended material reduction in terms of location and thickness. This allows for appropriate responses to different requirements along the vertical axis of the bumper cross member, and the design of the stiffening ribs can be optimized accordingly.

[0022] Particularly preferably, the bumper cross member is made of a hollow-chamber profile, for example, manufactured using an extrusion process. This allows the stiffening rib to be molded directly onto the corresponding vertical web, improving force transmission. Individual adaptation of the hollow-chamber profile thus provided is possible within the scope of various variants.

[0023] In particular, it may be provided to arrange the stiffening ribs flush with the respective flanges—and, if present, and / or internal supporting walls—on the vertical web. This ensures a flat force introduction, particularly into the horizontal sections of the bumper cross member that stiffen the bumper against bending.

[0024] It may also be provided that a bumper cross member is made of an aluminum alloy. A bumper cross member made of an aluminum alloy is particularly lightweight, but has the disadvantage of being softer than a bumper cross member made of highly hardened steel and, at the same time, more susceptible to cracking, especially when stress peaks occur. However, the cross-sectional design of a bumper cross member proposed here meets the requirements imposed by the aluminum alloy, thus improving the overall performance of the bumper cross member.This is attributed in particular to the possibility of equalising the stresses acting on such a bumper cross member during a crash by making particularly critical points that tend to crack locally softer in order to be able to better integrate the surrounding material into the absorption of the stress peaks, thus resulting in an overall homogenisation of the stress field.

[0025] To produce a described bumper cross member, it can be provided that in a first step a profile with a profiled cross section that can absorb a bending moment is provided with an outwardly facing vertical web that absorbs a crash force on the force application side, wherein at least one material-thickening stiffening rib is arranged on the vertical web, protruding from the vertical web in the direction of the applied crash force and running in the longitudinal direction of the bumper cross member.

[0026] In this first step, the stiffening rib preferably extends along the entire longitudinal extent of the bumper cross member.

[0027] In a second step, the stiffening rib is removed locally along its length in the longitudinal direction of the bumper cross member in order to achieve material reduction.

[0028] This results in a particularly cost-effective manufacturing process that particularly accommodates a wide variety of variants. The goal of the proposed design is precisely to adjust the bumper cross member at specific locations. Such an adjustment can be optimized for all possible vehicle variants using the method proposed here and, at the same time, can be produced using only a single tool.

[0029] It is preferably provided that the hollow profile is produced in the first step in an extrusion or pressing process, preferably from an aluminum alloy.

[0030] The invention is explained in more detail with reference to the accompanying figures. They show:

[0031] Fig. 1 : A comparison of an undeformed and a deformed bumper cross member in a cross-sectional view,

[0032] Fig. 2 : the undeformed bumper cross member of Figure 1 in a cross-sectional view,

[0033] Fig. 3 : the bumper cross member of Figure 1 in a plan view, Fig. 4 : the bumper cross member of Figure 3 in a plan view, but deformed after a pile test and

[0034] Fig. 5: the bumper cross member of Figure 1 in a three-dimensional oblique front view.

[0035] The bumper cross member 1 is installed in a vehicle not shown in detail. It is connected to a chassis C not shown in detail via longitudinal members using crash boxes C1, C2. The crash force F acting on the bumper cross member 1 acts on the force application side of the bumper cross member 1.

[0036] Figure 1 shows the bumper cross member 1 in a cross-sectional view in an undeformed (1a) and a deformed (1b) state. The undeformed cross-section is shown in dashed lines, the deformed cross-section in solid lines. Figures 3 and 4 show the bumper cross member 1 in a plan view before (Figure 3) and after (Figure 4) deformation during a pile test. During a pile test, a pile P is pressed onto the front of the bumper cross member 1 with a predetermined force.

[0037] For the sake of clarity, reference is made to Figure 2 below for the details of the cross-section design: The bumper cross member 1 is designed as an extruded hollow chamber profile made of an aluminum alloy and has three vertical webs 2, 3, 4 that are spaced apart from one another in the longitudinal axis direction L of the vehicle and arranged one behind the other when viewed in the direction of travel of the motor vehicle. The middle vertical web 3 is connected by means of upper and lower chords 5, 6, 7, 8 to the force application-side vertical web 2 on the one hand and to the chassis-side vertical web 4 on the other. The vertical webs 2, 3, 4 are thus supported against one another and form two hollow chamber zones Z1, Z2.

[0038] The force application side and thus front hollow chamber zone Z1 is formed by two hollow chambers H1, H2 separated by a supporting wall 9. The chassis side and thus rear hollow chamber zone Z2 is formed by a continuous hollow chamber H3 projecting beyond the two front hollow chambers H1, H2. Due to the supporting wall 9, which is formed in its end regions onto the central vertical web 3 and the force application side vertical web 2, the central vertical web 3 is supported more rigidly relative to the force application side vertical web 2 than the chassis side vertical web 4 is relative to the central vertical web 3. The supporting wall 9 has a waisted design (see area P6) so that a flat force introduction occurs from the central vertical web 3 and the force application side vertical web 2.

[0039] The distance between the force application side vertical web 2 and the central vertical web 3 in the longitudinal axis direction L of the motor vehicle is greater than the distance between the central vertical web 3 and the chassis side vertical web 4.

[0040] With reference to Figures 1, 3 and 4, the deformation behavior of the bumper cross member 1 according to the invention is explained in more detail:

[0041] During deformation, tensile forces occur in the chassis-side vertical web 4 due to the expansion in the longitudinal direction of the bumper cross member 1, pointing toward the crash boxes C1, C2. These tensile forces, due to the associated stress peaks, often lead to a tearing of the web facing away from the crash force F, in this case the chassis-side vertical web 4.

[0042] To counteract this, it is provided to provide the chassis-side vertical web 4 facing away from the crash force F with a deformation path in the event of deformation, in that it is supported less relative to the central vertical web 3 than the central vertical web 3 is relative to the force application side vertical web 2. Due to the lack of support - here: in the central region P5 relative to the central vertical web 3 - the chassis-side vertical web 4 can deform in such a way that its central region P5 bears against the central region 11 of the central vertical web 3. As a result, the central region P5 of the vertical web 4 is supported on the central region 11 of the central vertical web 3. The belts 7, 8 connecting the chassis-side vertical web 4 with the central vertical web 3 are correspondingly deformed in a round shape and represent the bumper cross member 1 as a whole as bending-stiffening, chassis-side ribs.The rear hollow chamber zone Z2 has collapsed in this way.

[0043] In contrast, there is the front hollow chamber zone Z1. Due to the retaining wall 9, which stiffens the front hollow chamber zone Z1 and supports the central vertical web 3 against the front vertical web 2 on the force application side, this zone is only slightly deformed and provides a rigid cross-sectional profile even after deformation. The two vertical webs 2, 3 of this hollow chamber zone Z1 remain essentially spaced apart from each other despite the deformation.

[0044] In order to promote the deformation of the chassis-side vertical web 4, an optimized cross-section of the bumper cross member 1 is presented here with reference to Figure 2:

[0045] The chords 7, 8, which connect the chassis-side vertical web 4 to the central vertical web 3, are curved by a rounding (area P3). This rounding has a radius of approximately 20 mm. The chords 7, 8 merge into the chassis-side vertical web 4. This area P3 contains material that stretches and thus thins out as the chassis-side vertical web 4 deforms.

[0046] This area P3 is followed by a sharply thinned area P4. After the deformation of the chassis-side vertical web 4, this thinned area P4 essentially provides the turning point, coming from the curve of the flanges 7, 8 toward the oppositely curved central area P5 of the chassis-side vertical web 4. The sharply thinned area provides a defined hinge area.

[0047] In order to relieve the chords 7, 8 with regard to their further curvature during deformation, the chords 5, 6 connecting the central vertical web 3 to the force-applied vertical web 2 are tapered in the area P2 of the connection to the central vertical web 3 (area P1). This tapering also creates a hinge in the area P2 of the transition of the upper chords 5, 7 and lower chords 6, 8 to the connection area of ​​the central vertical web 3, which, on the one hand, provides rigidity to the front hollow chamber zone Z1 and, on the other hand, counteracts crack formation due to stress peaks during deformation, in particular of the chassis-side vertical web 4.

[0048] The bumper cross member 1 shown here is furthermore supported by three stiffening ribs aligned with the belts 5, 6 and the supporting wall 9

[0049] 12, 13, 14 are additionally stiffened against bending. The stiffening ribs 12,

[0050] 13, 14 are arranged on the force application side vertical web 2 and thicken the material there in the direction of crash force F. The stiffening ribs 12, 13, 14 represent a projecting addition to the force application side vertical web 2.

[0051] As can be seen in Figure 5, the stiffening ribs 12, 13, 14 extend essentially in the longitudinal direction of the bumper cross member 1. The stiffening ribs 12, 14 are arranged in the upper and lower regions, respectively, in the end region of the bumper cross member 1. An additional stiffening rib 13 is arranged centrally with respect to the height of the bumper cross member 1.

[0052] The contour of the stiffening ribs 12, 13, 14 in the direction of the crash force F is straight, providing a flat force introduction surface 15, 16, 17. This prevents point loads.

[0053] The stiffening ribs 12, 13, 14 are formed as solid material in this embodiment. This opens up the possibility of individual local material reduction by machining. In the material-reduced areas M1.1, M1.2, M2.1, M2.2, the respective stiffening ribs 12, 13, 14 are completely interrupted in this embodiment, so that the underlying basic structure in the form of the force application side vertical web 2 is exposed. As a result of this measure, the bumper cross member 1 is deliberately made softer in these areas M1.1, M1.2, M2.1, M2.2 by reducing the area moment of inertia counter to the crash force F. Local stress peaks are thus avoided and the introduced crash force F is introduced in a homogeneous manner over the entire surface of the bumper cross member 1.2, the stiffening ribs 12, 13, 14 are designed with a reduced material over a certain area in which the bumper cross member 1 is connected on the chassis side, for example via crash boxes C1, C2. One crash box C1 of the two crash boxes C1, C2 has, in addition to the connection to the bumper cross member 1, a towing sleeve A. This additionally stiffens the bumper cross member 1 in its connection area. In order to prevent the bumper cross member 1 from cracking in this area, the additional stiffness is compensated for by reducing the material of the bumper cross member 1.

[0054] Also with reference to Figure 3, further areas M2.1, M2.2 of the stiffening ribs 12, 13, 14 have reduced material thickness, specifically in the center of the bumper cross member 1, in at least two areas arranged symmetrically to the center of the bumper cross member. These serve to form predetermined buckling points. In a pile test (see also Figure 4), these improve possible attachment to the pile P shown schematically here, even with large intrusion paths.

[0055] It can also be seen that in the direction of the stiffening ribs 12,

[0056] 13. 14 the transition 18, 19 to the material reduction of the stiffening ribs

[0057] 12. 13. 14 (shown in the figures only as an example) is concavely curved with a radius of at least the projection height V of the stiffening ribs 12, 13, 14 from the force application side vertical web 2.

[0058] The additional stiffening ribs 12, 13, 14 and, in particular, machining or removal in local areas M1.1, M1.2, M2.1, M2.2 of the stiffening ribs 12, 13, 14 create a simple and tool-independent possibility of influencing the area moment of inertia of the bumper cross member 1 in such a way that stress peaks that could result in the bumper cross member 1 cracking are avoided.

[0059] In addition, the stiffening ribs 12, 13, 14 provide the possibility of influencing the distribution of tensile and compressive stresses along the cross-section of the bumper cross member 1 in such a way that the neutral fiber - i.e. the plane in which the tensile and compressive stresses cancel each other out - can be adjusted with respect to the center of gravity and in particular with respect to the central vertical web 3. The stiffening ribs 12, 13, 14 shift the neutral fiber towards the force application side. Preferably, the neutral fiber is in the

[0060] Area of ​​the central vertical web 3, further preferably slightly offset from the force application side.

[0061] The invention has been described using an exemplary embodiment. Without departing from the scope of protection described by the applicable claims, numerous further embodiments will become apparent to those skilled in the art to implement the inventive concept without these having to be explained in more detail within the scope of these statements.

[0062] List of reference symbols

[0063] 1 bumper cross member

[0064] 2 vertical webs on the force application side

[0065] 3 middle vertical bar

[0066] 4 chassis-side vertical bar

[0067] 5. 7 Upper chord

[0068] 6. 8 Lower chord

[0069] 9 Retaining wall

[0070] P5 Center area of ​​the chassis-side vertical bar

[0071] 11 Central area of ​​the central vertical bar

[0072] 12, 13, 14 stiffening rib

[0073] 15, 16, 17 Force introduction area

[0074] 18, 19 Transition

[0075] V Stiffening rib projection height

[0076] P1 to P6 range

[0077] Z1 , Z2 hollow chamber zone

[0078] M1.1 , M1.2, M2.1 , material-reduced areas

[0079] M2.2

[0080] H1, H2, H3 hollow chamber

[0081] C Chassis

[0082] C1, C2 crash box

[0083] A towing sleeve

[0084] L Longitudinal axis direction of motor vehicle

[0085] P Post

[0086] F Crash force

Claims

Patent claims 1. Bumper cross member (1) for a motor vehicle with a profiled cross section capable of absorbing a bending moment and having an outwardly facing vertical web (2) which absorbs a crash force (F) on the force application side, wherein at least one material-thickening stiffening rib (12, 13, 14) is arranged on the force application side vertical web (2), which stiffens in material and projects from the vertical web (2) in the direction of the introduced crash force (F), is formed onto the force application side vertical web (2) and runs in the longitudinal direction of the bumper cross member (1), which stiffening rib is weakened locally along its course in the longitudinal direction of the bumper cross member (1) by material reduction in such a way that the force application side vertical web (2) remains closed despite the material reduction.

2. Bumper cross member according to claim 1, characterized in that the contour of the stiffening rib (12, 13, 14) is straight in the direction of load, providing a flat force introduction surface (15, 16, 17).

3. Bumper cross member according to claim 1 or 2, characterized in that the stiffening rib (12, 13, 14) is formed as solid material.

4. Bumper cross member according to one of claims 1 to 2, characterized in that the stiffening rib is designed as a hollow chamber, the wall of which facing away from the load is formed by the force application side vertical web of the profiled cross section.

5. Bumper cross member according to one of claims 1 to 4, characterized in that the material reduction of the stiffening rib (12, 13, 14) is carried out by machining.

6. Bumper cross member according to one of claims 1 to 5, characterized in that in the direction of extension of the stiffening rib (12, 13, 14) the transition to the material reduction (M1.1, M1.2, M2.1, M2.2) of the stiffening rib (12, 13, 14) is concavely curved with a radius of at least the projection height (V) of the stiffening rib (12, 13, 14) from the force application side vertical web (2).

7. Bumper cross member according to one of claims 1 to 6, characterized in that the region (M1.1, M1.2, M2.1, M2.2) in which the stiffening rib (12, 13, 14) is reduced in material is flush with the material surrounding the stiffening rib (12, 13, 14).

8. Bumper cross member according to one of claims 1 to 7, characterized in that the stiffening rib (12, 13) in the area (M1 .1, M1 .2) of the connection of the bumper cross member (1) to a longitudinal member, such as a crash box (C1, C2), in particular in the area of ​​the towing sleeve (A), is made of reduced material.

9. Bumper cross member according to one of claims 1 to 8, characterized in that the stiffening rib (12, 13, 14) in the central region of the bumper cross member (1) is reduced in material in at least two regions (M2.1, M2.2) arranged symmetrically to the center of the bumper cross member in order to form predetermined bending points.

10. Bumper cross member according to one of claims 1 to 9, characterized in that the force application side vertical web (2) has a stiffening rib (12, 14) in the upper and lower regions.

11. Bumper cross member according to one of claims 1 to 10, characterized in that the force application side vertical web (2) has a stiffening rib (13) centrally in relation to its height.

12. Bumper cross member according to one of claims 1 to 11, characterized in that the bumper cross member (1) is provided from a hollow chamber profile.

13. Bumper cross member according to one of claims 1 to 12, characterized in that the hollow chamber profile is provided from an aluminum alloy.

14. A method for producing a bumper cross member (1) according to one of claims 1 to 13, wherein in a first step a profile with a profiled cross section that can absorb a bending moment and has an outwardly facing vertical web (2) that absorbs a crash force (F) on the force application side is provided, wherein on the vertical web (2) at least one stiffening rib (12, 13, 14) is arranged that thickens the material, projects from the vertical web (2) in the direction of the introduced crash force (F), is formed onto the force application side vertical web (2) and runs in the longitudinal direction of the bumper cross member (1), and in a second step the stiffening rib (12, 13, 14) is removed locally along its course in the longitudinal direction of the bumper cross member (1) by machining in such a way that the force application side Vertical bar (2) remains closed despite material reduction.

15. The method according to claim 14, characterized in that the profile is produced in the first step in an extrusion process, preferably from an aluminum alloy.

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