Bumper arrangement

Abstract

Bumper arrangement (1) with a cross member (2), wherein the cross member (2) is designed as a hollow profile with a front wall (9), a rear wall (10), an upper wall (11) and a lower wall (12), wherein the front wall (9) has a bead (20) which extends in the longitudinal direction of the cross member (2), wherein the bead (20) has a deepest region (21) which runs at a distance (D1) from the rear wall (10), wherein the upper and lower walls (11, 12) in the end regions (3, 4) each have at least one further bead (24, 25) which extends in the longitudinal direction of the cross member (2), so that the upper wall (11) and the lower wall (12) are more strongly beaded in the end regions (3, 4) than in a central region (13) of the cross member (2), so that the distance between the front wall (9) and the rear wall (10) in the end regions (3, 4) is smaller than in the central region (13) of the cross member (2), characterized in thatthat the bead (20) extends over the entire length of the cross member (2), wherein two deformation elements (5, 6) are arranged between end regions (3, 4) of the cross member (2) and longitudinal members (7, 8) of a motor vehicle.,

Description

The invention relates to its bumper arrangement according to the preamble of claim 1.The invention relates to a bumper arrangement having a cross member and having two deformation elements (crash boxes) for arrangement between end sections of the cross member and longitudinal members of a motor vehicle, in particular of a passenger car. The cross member is designed as a hollow profile with a front wall, a rear wall, an upper wall and a lower wall. The hollow profile can be produced as an extruded profile with a single-chamber or multi-chamber cross section (EP 2 325 058 A2). Bumper systems of this type, which are installed on the front and rear sides as standard in motor vehicles in order to absorb the impact energy of smaller impacts, must meet different requirements and crash scenarios. The cross member should be light and flexurally rigid, so that the impact force can be introduced into the deformation elements. At the same time, the bending stiffness of the cross member must not be too high to have the necessary flexibility in the event of an impact at a higher speed to absorb energy by deformation of the cross member. At the same time, the cross member should not buckle in an uncontrolled manner under a high point load or even tear off the crash box.U.S. Pat. No. 8,690,207 B2 discloses a bumper arrangement having a cross member and two integrally formed deformation elements (crash boxes) for arrangement between end sections of the cross member and longitudinal members of a motor vehicle. The cross member is designed as an extruded profile. The structural form has a deep bead in the front side, which runs at a distance from the rear side and serves for stiffening the hollow profile. In the end forming region, the bead becomes flatter, so that the deformation body of larger cross section can be formed.JP 2003-146 156 A discloses a bumper cross member having two deformation elements for arrangement between end regions of the cross member. For stiffening the cross member, a bead is arranged in the front wall, which is welded to the rear wall. The end regions can have additional beads in their upper and lower walls, so that the distance between the front wall and the rear wall becomes smaller, while at the same time the bead is always supported on the rear wall.US 5 498 045 A discloses a blow molded bumper cross member fastened to a motor vehicle with U-bolts. The deformation behavior of the cross member is influenced by arranging beads in an upper-side and / or lower-side wall, which beads are located in particular in the end region. This design does not provide separate deformation elements in the end regions, but is instead to be made of a plastic in order to reduce weight, costs and assembly effort. Beads in the upper and lower walls are intended to prevent these regions from being bent outwards and damaging nearby components in the event of an impact. The beads have a function that the upper and lower walls are deformed inward to protect attachments.U.S. Pat. No. 10,835,942 B2 discloses a bumper arrangement having a cross member, wherein the cross member is designed as a hollow profile and has a front wall, a rear wall, an upper wall and a lower wall. The front wall has a bead which extends in the longitudinal direction of the cross member. The bead has a deepest region which extends at a distance from the rear wall. The upper and the lower walls each have a further bead in the end regions, which extends in the longitudinal direction of the cross member, so that the upper wall and the lower wall are more strongly embroidered in the end regions than in a central region of the cross member. As a result, the distance between the front wall and the rear wall is smaller in the end regions than in the central region of the cross member. This is an extruded hollow support made of aluminum, which is subsequently heated in order to configure the end regions in particular by plastic deformation.The object of the invention is to provide a bumper arrangement in which the cross member has both a high rigidity in order to better meet the requirements for impact tests at low speeds, but at the same time has the necessary flexibility in order to better meet the test requirements at higher impact speeds.This object is achieved in a bumper arrangement having the features of claim 1.The dependent claims relate to advantageous further developments of the invention.The bumper arrangement according to the invention comprises a cross member and two deformation elements (crash boxes). The crash boxes are arranged between longitudinal members of a motor vehicle and end regions of the cross member. The cross member is designed as a hollow profile. In particular, it is an extruded single- or multi-chamber profile. In particular, it is a single-chamber profile. The hollow profile has a substantially rectangular cross section with a front wall, a rear wall, an upper wall and a lower wall. A deep bead is arranged in the front wall. The bead extends in the longitudinal direction of the cross member. The bead is oriented toward the rear wall and has a deepest region which runs at a distance from the rear wall. In the upper and lower walls, at least one further bead is arranged in each case in the end region. These further beads likewise extend in the longitudinal direction of the cross member. The bead in the front wall is preferably open towards the outer ends of the end portions.The further beads in the upper and lower walls result in the upper wall and the lower wall being more curved in the end regions than in a central region of the cross member. As a result, the distance between the front wall under the rear wall is smaller in the end regions than in the central region of the cross member. In other words, the depth of the cross member measured in the longitudinal direction of the motor vehicle is smaller in the end sections because the front wall is located closer to the rear wall.By reducing the distance between the front wall and the rear wall, the distance of the deepest region of the bead from the rear wall is smaller in the end regions. This reduction has a significant effect on the deformation profile. If the cross member deforms too easily in its end regions, for example because its upper and lower walls buckle, this leads to the crash box being deformed only with a time delay. This time delay can lead to a drop in the force-path curve in a force-path diagram, in which the force required for deformation is plotted against the depth of penetration into the motor vehicle. As a result, the maximum permissible force and the deformation work resulting therefrom cannot be optimally utilized as the product of force x travel. The invention aims to deform the crash box at an earlier point in time before the deformation of the cross member is completed. For this purpose, regions of the crash box could be provided with triggers, for example with structures in order to make the crash box more impact-softer. According to the invention, however, a different or additional route is selected. The bead in the front wall is the trigger for the crash box. Therefore, the bead is particularly deep in the region of the deformation elements, i.e. in the region of the end regions of the cross member located upstream. The distance between the front wall and the rear wall is adjusted in a targeted manner such that the deepest region of the bead touches the rear wall of the cross member early in the event of an impact. At the same time, the end region must be comparatively flexurally soft, which is achieved by the greater curvature of the upper and lower walls. In addition, the bead is configured to be more rigid than the upper and lower walls, so that the impact force can be transmitted from the front wall via the bead into the rear wall. As a result of this load path via the bead into the rear wall, the crash box is loaded earlier with a higher impact force, so that the deformation of the deformation elements begins earlier. As a result, the force-displacement characteristic curve has a smaller drop in the force because the energy absorption of the cross member is superimposed by the energy absorption of the deformation elements. This means that more deformation work can be performed with a smaller penetration depth or, without the penetration depth being increased, higher impact forces can be absorbed.A further advantage of the bumper arrangement according to the invention is likewise attributable to the beads in the upper and lower walls. Said beads are arranged in the end regions in order to bend the upper and lower walls more strongly there. As a result, the central region behaves more flexurally rigid than the end regions. The beads are partially compressed in the event of an impact which does not take place in the region of the crash boxes, but rather in the central region of the cross member. At the same time, the same beads in the outer end regions, i.e. at the free ends of the cross member, have the effect that the upper and lower walls can be stretched, so that the distance between the front wall and the rear wall is increased. These properties of the beads, namely, to be able to compensate compressive stresses and tensile stresses, allow the cross member to rotate about the inner front edge of the deformation elements, i.e., about the region of the crash boxes facing the vehicle central longitudinal axis. The ends of the cross members are widened in this load case, while the portions of the end region lying further inward are compressed. Both in turn contribute to the energy dissipation.The end portions therefore have a relatively high flexibility. On the one hand, in the event of an impact in the region of the deformation elements, the deep bead touches the rear wall at an early stage and thus initiates the deformation of the crash box. On the other hand, in another load case, the previously described rotational movement is to be made possible, in which the outer ends of the cross members are widened and the sections of the end regions arranged to form the transition region are compressed.The cross member is preferably an extrusion profile, in particular a single-chamber profile. The beads in the end regions are subsequently produced by forming the extruded profile. It is possible to produce the bead in the front wall finally by means of extrusion. It is possible to deepen the bead subsequently.Preferably, the bead in the front wall has, due to the production, a cross section which remains the same over the entire length of the bumper arrangement. The cross member may be curved to conform to a configuration of a front end of a motor vehicle, with the concave side of the cross member facing the center of the vehicle, respectively. In adaptation to the curved rear wall of the cross member, the deformation elements have front sides which are adapted to the orientation of the rear wall of the cross member. The deformation elements can be adapted to the height of the cross member or can be configured to be lower. However, they can also be higher than the cross member and project or engage over the latter at the top and / or at the bottom.The invention includes that the extrusion profile is a multi-chamber profile. In this case, however, any inner walls in the end regions should be removed, so that the deepest region of the bead in the end regions runs at a distance from the rear wall. The beads should initially, i.e. before the crash, not be in contact with the rear wall in the end regions, but should have a depth which enables early force transmission between the front wall and the rear wall or the adjoining crash box.The bead in the front wall is of particular importance in the region of the end sections. The smaller distance from the rear wall in the region of the end sections is important. In the central region of the cross member, the distance is greater. As a result, the cross member has a higher bending stiffness in the central region than in the end regions. The effect of a cross member configured in this way is that there is just no very impact-resistant connection between the cross member and the deformation elements, but rather a cross member which is allowed to deform and which is intended to be able to execute a rotational movement in the region of the crash boxes. The outermost end of the cross member is intended to be stretched in a targeted manner, while the cross member is compressed on the mutually facing inner sides of the crash boxes. More energy is absorbed by the deformation during the rotation and lower forces are introduced into the deformation elements. At the same time, the material is not overloaded due to the yieldable beads in the upper and lower walls. Fractures can be avoided both in the region of the cross member and in the region of the deformation elements. In this way, shorter crash boxes can again be used. As a result, the total weight of the arrangement and also the construction volume can be reduced. These advantages are the result of early, high energy absorption. This in turn is a consequence of the deformation elements being loaded early. Without the bead in the front wall, the cross member would be able to be deformed completely before the deformation elements would be deformed. The advantages of the invention are therefore also due to the more necked upper and lower walls in the end portions. A stronger kicking of the upper and lower walls is to be understood in the sense of a specifically set desired deformation in this region, which is to take place more easily in the end regions than in the middle region.In a further development of the invention, the bead in the front wall has in particular a trapezoidal cross section. The bead should have a shape which makes it possible to introduce the force from the impact as early as possible into the crash box. The trapezoidal cross section has the advantage that the flanks of the cross section, i.e. an upper and a lower wall of the bead, can be almost perpendicular to the front wall. This means that the impact forces can be introduced via these walls directly into the deepest region of the bead and thus into the rear wall of the cross member. A deep bead simultaneously increases the bending stiffness of the bumper arrangement. The bead should therefore preferably have a depth which is greater than 50% of the depth of the cross member measured in the longitudinal direction of the motor vehicle. The bead can have a uniform depth overall. Due to the reduced depth of the cross member in the end regions, the proportion of the total depth occupied by the bead is correspondingly greater. It is considered to be particularly favorable if the bead of the front wall has a depth in the region of the end regions which is greater than 75% of the depth of the cross member measured in the longitudinal direction of the motor vehicle, in particular than 75% of the depth of the cross member measured in the end region.In addition, the bead should have a height measured in the vertical direction of the motor vehicle, which preferably extends over 25 to 50% of the height of the cross member. The height of the cross member is defined by the outer distance between the upper wall and the lower wall in the central region. The cross member may additionally have flanges on the upper and lower wall, for example for fastening the cross member to the deformation elements. In the same way, flanges which project above the upper wall or lower wall at the height can also be arranged in the region of the front wall upwards and / or downwards locally or continuously. In the case of cross members which do not have a constant height over their entire length, details of heights or depths of the beads relate to the arithmetically averaged height in the respective end region or middle region.It is considered advantageous if the distance between the bead of the front wall and the rear wall is in a range from 5 to 10 mm. This allows smaller loads to be absorbed without the crash box being deformed. If the loads increase, the bead serves as a non-impact trigger in order to introduce the force via the rear wall into the crash boxes at an early stage.It is considered to be advantageous if the front wall with the bead has a greater wall thickness than the walls of the deformation elements. The force is to be transmitted via the front wall. The front wall and also the bead on the front wall should not deform very early as possible, at least not before the forces have been introduced into the deformation elements. The thickness ratio (front wall, deformation element) is preferably in a range greater than 1.5. 2.4 mm, while the front wall has a wall thickness of 4 mm.Particularly preferably, different materials or metal alloys, in particular different aluminum alloys, are also used for the deformation elements and the cross member. The 0.2% yield strength Rp0.2is preferably at least 300 MPa for the cross member and at least 240 MPa for the crash boxes.In addition, triggers can be arranged in the crash boxes, for example in the form of openings or beads. Triggers support a controlled and uniform deformation of the crash boxes. In particular, the upper and lower walls of the crash boxes can be designed to be more flexurally softer, since the upper and lower walls of the cross member, as a result of the beads introduced there, are also softer in the end regions in the sense of being more flexible than the central region of the cross member, in which the bead is arranged in the front wall for transmitting the impact force.Between the central region and the outer end regions there is in each case a transition region of the cross members. The depth of the cross member changes in the transition region because the distance of the bead from the rear wall is to be reduced. This was done by plastic forming. In this case, in particular the rear wall in the transition region should be more strongly curved than the front wall. The course of the front wall is generally determined by the front or rear contour of a motor vehicle. The greater curvature in the rear wall leads to an S-shaped curvature being formed in this region.The cross member according to the invention can be produced cost-effectively by a cross section of the bead in the front wall that is as uniform as possible. Preferably, the distance between the rear wall and the deepest region of the bead is as small as possible at least in the end regions for crash technology reasons and is in particular in a range between 5 mm and at most 30% of the depth of the cross member measured in the central region of the cross member and in the longitudinal direction of the motor vehicle. From a crash perspective, the distance is particularly preferably between 5 mm and a maximum of 20 mm. From the manufacturing point of view or as a result of extrusion, a distance below 10 mm can be realized more difficultly than larger distances without subsequent press forming, so that the distance is preferably 10 mm to 20 mm. Smaller values can be achieved by re-pressing, since the end regions are stamped in a press in any case.The depth of the bead in the front wall is preferably at least 15 mm. The beads in the upper and lower walls preferably have a depth of 5 to 10 mm. Beads of lesser depth may also extend over the entire length of the bumper arrangement in the upper and lower walls, but they have a significantly lesser depth in the central region. Preferably, the upper and lower walls are substantially straight.The end sections have a depth measured in the direction of travel that is less than the central region of the cross member. The end sections can be compressed by 5 to 10 mm, for example. The upper and lower walls should have wall thicknesses which should be not greater than 4.5 to 5 mm in order to realize sufficient bending rigidity in the central region of the cross member. The bending stiffness in the end sections is reduced by the beads additionally introduced there.The invention is explained in more detail below with reference to exemplary embodiments illustrated in purely schematic drawings. The following are shown: FIG. 1 shows a bumper arrangement in a plan view; FIG. 2 shows an end region of the bumper arrangement in a plan view; FIG. 3 shows an end region of the bumper arrangement in a perspective view; FIG. 4 shows a sectional illustration through the end region of the cross member before a crash; FIG. 5 shows a cross section through the end region of the cross member during a crash; FIG. 6 shows a force-displacement diagram during the crash; FIG. 7 shows a further crash situation in plan view, and FIG. 8 shows the crash situation of FIG. 7 in a perspective view of an end region.FIG. 1 shows a bumper arrangement 1 with a cross member 2 made of an extruded hollow profile. The cross member 2 has end regions 3, 4, by means of which the cross member 2 is fastened to deformation elements 5, 6. The deformation elements 5, 6 (crash boxes) are provided for fastening to longitudinal members 7, 8 of a motor vehicle, not shown in any more detail. The cross member 2 is slightly curved. Its concave rear side faces the vehicle center. Its convex front faces away from the vehicle. A cartesian coordinate system shows X, Y and Z directions, to which reference is made below. The X direction points in the longitudinal direction of the vehicle, which is not shown in detail. A depth T 1 of the cross member 2 is measured in the X direction. A height H 1 (FIG. 4 ) is measured in the Z direction. The longitudinal direction of the cross member 2 means the course along the longitudinal axis of the cross member 2. In this sense, a front wall 9 and a rear wall 10 extend in the longitudinal direction of the cross member 2, as well as an upper wall 11 and a lower wall 12 (FIG. 3 ) extend parallel to one another.It can be seen from the illustration in FIG. 1 that the cross member 2 has a central region 13. In this region 13, the cross section of the cross member 2 is constant. Adjoining the middle region 13 in the direction of both ends is a transition region 14, 15. The transition regions 14, 15 are followed by the end regions 3, 4. The cross member 2 is constructed substantially mirror-symmetrically with respect to its central transverse plane MQE. Differences result at most from the fact that an aperture for a towing device is arranged in the right end region 4. The damping elements 5, 6 are also substantially symmetrical in this sense. Adaptations result only from the need to connect a towing device to the longitudinal member 8, which is preceded by the deformation element 6.FIG. 2 shows an enlarged illustration of one of the end regions 3 of the cross member 2, the end region 3 being wider than the transition region 14. The depth T 1 is reduced in the transition region 14. In the transition region 14, the course of the front wall 9 is curved somewhat more strongly, wherein the course of the front wall 9 continues substantially linearly in the region of the deformation element 5. The rear wall 10 runs parallel to the front wall 9 both in the central region 13 and in the end region 3; deviations therefrom occur only in the transition region 14. This course has been produced by plastic deformation of the end region 3 and of the transition region 14.The deformation element 5 has a flange plate 18 for fixing to the motor vehicle. Instead of the flange plate, the deformation element can also be inserted into a longitudinal member of the motor vehicle and can be designed to be screwed thereon. A front side 19 of the deformation element 5 does not run parallel to the flange plate 18, but is adapted to the course of the rear wall 10 of the cross member 2. The front side 19 of the deformation element 5 and the rear wall 10 of the cross member 2 are firmly connected to one another.FIG. 3 shows a perspective view of the cross section of the cross member 2, the cross member 2 having a bead 20 in its front wall 9, it extends over the entire length of the cross member 2, it being an open bead because it also extends through the end regions 3, 4 and is open towards the outermost ends of the cross member 2. The bead 20 has a trapezoidal cross section with a deepest portion 21, which deepest portion 21 extends parallel to the rear wall 10, which deepest portion 21 of the bead 20 is located closer to the rear wall 10 than to the front wall 9.It can be seen from the illustration in FIG. 3 that the horizontal distance D 1 (FIG. 4 ) from the deepest region 21 to the rear wall 10 is relatively small. It is in the region of the end region 3 of an order of magnitude between 5 and 10 mm. Accordingly, the bead 20 is relatively deep. The bead depth T 3 of the bead 20 is greater than 50% of the depth T 1 of the cross member 2 measured in the longitudinal direction, i.e. in the X direction of the motor vehicle.The height H 2 of the bead 20 is also relatively large in relation to the height H 1 of the cross member 2, measured externally between the upper wall 11 and the lower wall 12. The height H2 increases from the deepest portion 21 to the mouth of the bead 20, i.e., toward the front wall 9, because the upper bead wall 22 and the lower bead wall 23 are slightly inclined. The upper bead wall 22 and the lower bead wall 23 otherwise extend straight. As a result, the height H2 extends in the region of the front wall 9 over 25 to 50% of the height H1 of the cross member 2.The large bead depth T 3 of the bead 20 has the effect that, in the event of an impact on the front wall 9, the deepest region 21 makes early contact with the rear wall 10. Figure 5 shows this early time of impact. The bead 20 or the deepest region 21 with the upper and lower bead walls 22, 23 should here be relatively stiff, while the upper wall 11 and the lower wall 12 should be flexible. For this reason, a further bead 24 is located in the upper wall 11, and a corresponding bead 25 is also located in the lower wall 12, FIG. 3 showing that the beads 24, 25 are open toward the free end of the cross member 2. The beads 24, 25 are located in the end regions 3, 4 and begin in the transition regions 14, 15. The beads 24, 25 are produced by forming the end regions 3, 4 while the rear wall 10 has been displaced in the direction of the front wall 9. The beads 24, 25 are directed inwardly, i.e. toward the deep bead 20 in the front wall 9. It is clear from the illustration of FIG. 3 that there is likewise a bead 24 ain the middle region 13 in the upper wall 11. However, this bead 24 ais very flat, so that the upper wall 11 as well as the identically designed lower wall 12 can be considered substantially straight or extended. As a result, the thickness and the resulting curvature of the upper wall 11 and the thickness of the lower wall 12 is greater in the end regions 3, 4 than in the central region 13 due to the deeper beads 24, 25.FIG. 5 shows the sectional view according to FIG. 4 at a point in time shortly after the deepest region 21 of the bead 20 touches the rear wall 10. The rear wall 10 is intended to be specifically deformed, so that the deformation continues into the deformation element (not shown in more detail here). The bead 20 thus serves as a trigger for the deformation element in order to already begin the deformation of the deformation element before the deformation of the end region 3, 4 of the cross member 2 is concluded. It can be seen from the illustration that the beads 24, 25 deform in this case, unlike the deep bead 20 in the front wall 9.FIG. 6 shows a force-path diagram in which the force occurring during the deformation is plotted over the penetration depth during an impact. In addition, a sectional illustration through a left-side bumper connection is illustrated. The same reference numerals are used as those introduced in the aforementioned embodiments. At an early time of the crash, the test body 26 initially deforms only the end regions of the cross member 2, wherein the bead 20 abuts with its deep-lying region 21 on the rear wall 10. The rear wall 10 is deformed in its central height region, so that the deformation of the deformation element is initiated. It can be seen from the course of the curve that a relatively constant force course is established until the maximum penetration depth is reached. In the plane of the drawing on the right, the simulation shows that when the maximum penetration depth is reached, the bead 20 has penetrated relatively far into the deformation element 6. The deformation element 6 is deformed such that the end region of the cross member 2 has penetrated deeper into the deformation element 6 in the middle height region of the deformation element than in the upper and lower height region of the deformation element 6.While FIG. 6 shows a low speed impact, FIGS. 7 and 8 show another load case. A test specimen 27 engages in the central region of the motor vehicle. The impact velocity is high. As a result, two deformation regions of the cross member 2 are formed in the region of the crash box. In a region 28 marked as "compression", the cross member 2 is compressed as a result of the beads 24, 25 in the upper wall 11 and in the lower wall 12. At the same time, a tensile force is exerted on an outermost end region 29 of the cross member 2 by the torque M 1. This region is marked as "tension". This tensile force leads to this region being widened.It can be seen from the perspective illustration of FIG. 8 that the beads 24, 25 in the upper wall 11 and the lower wall 12 have been stretched by the impact. The beads 24, 25 serve as expansion joints to a certain extent in order to prevent the cross member 2 from tearing off the deformation element 6 at particularly high torques M 1. If the cross member 2 were to tear off the deformation element 6 in the region 29, no deformation energy could be absorbed in the end region 3. Only a rotation around the region 28 would occur. The beads 24, 25 in the upper and lower walls 11, 12 thus have a dual function depending on the crash scenario.Reference Number:1 Bumper arrangement 2 Cross member 3 End region of 2 4 End region of 2 5 Deformation element 6 Deformation element 7 Longitudinal member 8 Longitudinal member 9 Front wall of 2 10 Rear wall of 2 11 Upper wall of 2 12 Lower wall of 2 13 Middle region of 2 14 Transition region to 13 15 Transition region to 13 18 Flange of 5 19 Front side of 5 20 Bead 21 Deepest region of 20 22 Upper bead wall 23 Lower bead wall 24 Bead of 11 in 3 24a Bead of 11 in 13 25 Bead in 12 26 Test body 27 Test body 28 Region of 2 29 Region of 2 D1 Distance between 21 and 10 H1 Height of 2 H2 Height of 20 MQE Central transverse plane T1 Depth of 2 in 13 T2 Depth of 2 in 16 T3 Bead depth of 20 X Longitudinal direction the vehicle Y transverse direction of the vehicle Z vertical direction of the vehicle

Claims

Bumper arrangement (1) with a cross member (2), wherein the cross member (2) is designed as a hollow profile with a front wall (9), a rear wall (10), an upper wall (11) and a lower wall (12), wherein the front wall (9) has a bead (20) which extends in the longitudinal direction of the cross member (2), wherein the bead (20) has a deepest region (21) which extends at a distance (D1) from the rear wall (10), wherein the upper and lower walls (11, 12) in the end regions (3, 4) each have at least one further bead (24, 25) which extends in the longitudinal direction of the cross member (2), such that the upper wall (11) and the lower wall (12) in the end regions (3, 4) are more strongly embroidered than in a central region (13) of the cross member (2), such that the distance between the front wall (9) and the rear wall (10) in the end regions (3, 4) is smaller than in the central region (13) of the cross member (2), characterized in that the bead (20) extends over the entire length of the cross member (2), wherein two deformation elements (5, 6) are arranged between end regions (3, 4) of the cross member (2) and longitudinal members (7, 8) of a motor vehicle.Bumper arrangement (1) according to Claim 1, characterized in that the cross member (2) is an extruded profile, wherein the beads (24, 25) in the end regions (3, 4) are produced by forming.Bumper arrangement (1) according to Claim 1 or 2, characterized in that the bead (20) in the front wall (9) in the region of the end regions (3, 4) is at a smaller distance (D1) from the rear wall (10) than in the central region (13) of the crossmember (2).Bumper arrangement (1) according to Claim 1 or 2, characterized in that the bead (20) in the front wall (9) has a trapezoidal cross section.Bumper arrangement (1) according to one of Claims 1 to 4, characterized in that the bead (20) in the front wall (9) has a bead depth (T3) which is greater than 50% of the depth (T1) of the cross member (2) measured in the longitudinal direction of the motor vehicle.Bumper arrangement (1) according to one of Claims 1 to 5, characterized in that the bead (20) of the front wall (9) has, in the region of the end regions (3, 4), a bead depth (T3) which is greater than 75% of the depth (T1) of the cross member (2) measured in the longitudinal direction of the motor vehicle.Bumper arrangement (1) according to one of Claims 1 to 6, characterized in that the bead (20) of the front wall (9) has a height (H2) which is measured in the vertical direction of the motor vehicle and extends over 25 to 50% of the height (H1) of the crossmember (2).Bumper arrangement (1) according to one of Claims 1 to 7, characterized in that the distance (D1) between the bead (20) of the front wall (9) and the rear wall (10), at least in the end regions (3, 4), is between 5 mm inclusive and at most 30% of the depth (T1) of the cross member (2) measured in the central region (13) in the longitudinal direction of the motor vehicle.Bumper arrangement (1) according to Claim 8, characterized in that the distance (D1) between the bead (20) of the front wall (9) and the rear wall (10) is between 5 and 20 mm inclusive.Bumper arrangement (1) according to either of Claims 8 and 9, characterized in that the distance (D1) between the bead (20) of the front wall (9) and the rear wall (10) is between 10 and 20 mm inclusive.Bumper arrangement (1) according to one of Claims 1 to 10, characterized in that the front wall (9) with the bead (20) has a greater wall thickness than walls of the deformation elements (5, 6).Bumper arrangement (1) according to one of Claims 1 to 11, characterized in that transition regions (14, 15) to the central region (13) of the cross member (2), where the depth (T1, T2) of the cross member (2) measured in the vehicle longitudinal direction changes, are arranged at the end regions (3, 4), wherein the rear wall (10) is curved more strongly in the transition regions (14, 15) than the front wall (9).

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