Crossbeam for a crash management system

Abstract

Crossbeam (10) for a crash management system (100) for a motor vehicle, wherein the crossbeam (10) extends substantially along a transverse direction (Y) and is attachable to a vehicle structure, preferably by means of two crash boxes (24) arranged at a distance from each other on the crossbeam (10), and wherein the crossbeam (10) has a closed cross-section with a front belt (12), a rear belt (14), a first transverse wall (16) and a second transverse wall (18), wherein the transverse walls (16, 18) connect the front belt (12) to the rear belt (14), wherein the front belt (12) is spaced apart from the rear belt (14) in a longitudinal direction (X) and wherein the transverse walls (16, 18) are spaced apart from each other in a vertical direction (Z), characterized in that the transverse walls (16, 18) each have an embossing (20), preferably directed towards the interior of the crossbeam (10), 22) exhibit the markings (20,22) are formed in a central area (M) of the crossbeam (10) in the transverse direction (Y).

Description

[0001] The present invention relates to a cross member for a crash management system for a motor vehicle according to the preamble of claim 1.

[0002] Crossmembers for crash management systems are known from the prior art. In a motor vehicle, these fulfill various passive safety functions, for example, by absorbing impact energy through controlled deformation. Installation space in motor vehicles, especially passenger cars, is very limited, thus restricting the scope for deformation of the crossmember. Furthermore, various sensitive components, such as components of a cooling system, can be located close to the crossmember, and these components must be protected from damage caused by the deformation of the crossmember. To achieve this, EP 2 318 237 B1 discloses a crossmember with an optimized shape, wherein a rear flange of the crossmember is angled and a transverse wall is shortened by embossing. In the event of an impact, the crossmember is twisted, and the angled design reduces displacement of the rear flange.Another requirement placed on a cross member by vehicle manufacturers concerns compliance with tight dimensional tolerances of the component.

[0003] Against this background, the present invention aims to propose a crossbeam for a crash management system that exhibits both favorable mechanical deformation behavior and improved dimensional accuracy after manufacturing.

[0004] This problem is solved with a crossbeam having the features of independent claim 1.

[0005] The invention relates to a cross member for a crash management system for a motor vehicle, wherein the cross member extends substantially along a transverse direction and is preferably attachable to a vehicle structure by means of two crash boxes arranged at a distance from each other on the cross member, and wherein the cross member has a closed cross-section with a front belt, a rear belt, a first transverse wall and a second transverse wall, wherein the transverse walls connect the front belt to the rear belt, wherein the front belt is spaced apart from the rear belt in a longitudinal direction and wherein the transverse walls are spaced apart from each other in a vertical direction.

[0006] According to the invention, the transverse walls each have an embossing, preferably directed towards the interior of the crossbeam, wherein the embossings are formed in a central area of ​​the crossbeam in the transverse direction.

[0007] For the purposes of this application, the term "embossing" refers to a locally limited shaping of a component, which is produced by a forming process and / or during a manufacturing process, in particular a bending process. The embossings can be indentations directed inwards, i.e., into the closed cross-section of the crossbeam, and / or outwards, i.e., outside the closed cross-section of the crossbeam.

[0008] The structural component according to the invention offers the advantage of a defined deformation behavior under stress as well as improved dimensional accuracy as a result of targeted shaping by forming, in particular by symmetrical embossing of the upper transverse wall and the lower transverse wall of the crossbeam.

[0009] By embossing both transverse walls, undesirable deformation of the crossbeam around a longitudinal X-axis, which can occur with embossing of only one transverse wall, is effectively prevented. The crossbeam according to the invention therefore exhibits particularly high dimensional accuracy and reliably meets even tightly specified dimensional tolerances. Additional, complex post-processing steps, especially a straightening process, are therefore unnecessary.

[0010] Advantageous embodiments of the crossbeam according to the invention are the subject of the following description, figure description, figures and dependent claims.

[0011] In a first advantageous embodiment of the cross member, the embossing can be designed such that the rear flange has a chamfer inclined towards the front flange in both an upper and a lower section, with the chamfers reducing the distance between the rear and front flanges in the upper section towards the first transverse wall and in the lower section towards the second transverse wall. The design of chamfers on both sides of the cross member offers the particular advantage over a chamfer on only one side that optimized crash behavior is always achieved, regardless of any twisting of the cross member that may occur under load or in a crash. In particular, optimized crash behavior is achieved regardless of the specific crash scenario involving a taller or shorter opposing vehicle.In both cases, the chamfers on both sides provide the rear belt of the cross member with an increased installation space within which the cross member can deform before the rear belt comes into contact with a rearwardly arranged component of the vehicle itself.

[0012] The embossing of the transverse walls advantageously results in the rear chord being angled relative to the front chord, preferably such that the distance between the rear chord and the front chord at a central wall is greater than the distance at the first transverse wall and / or the distance at the second transverse wall. The angled design of the rear chord advantageously supports compliance with deformation limits. In other words, the angled design ensures that the rear chord remains within the predefined deformation limits during torsion of the crossbeam and does not exceed these limits in the area of ​​a transverse wall.

[0013] In a further advantageous embodiment of the crossbeam, the length of the central section can be 0.2 to 0.4 times, preferably 0.25 to 0.35 times, the length of the rear flange in the transverse direction. It is particularly advantageous for the crossbeam to have the embossing in the central section and to be free of embossing outside this area. In this way, the embossing in the central section ensures compliance with deformation limits, and any undesirable weakening effects of the embossing are limited to this area and thus reduced or minimized. In other words, the embossing is only present in the area where its beneficial effect is required, resulting in a load-bearing crossbeam overall.

[0014] In a further advantageous embodiment of the crossbeam, the embossing can be formed as a recess on the outside of the respective cross wall and as a bulge on the inside of the respective cross wall. A particularly advantageous feature of this embodiment is a constant or at least a minimally varying wall thickness of the cross walls in the area of ​​the embossing, which leads to advantageous mechanical properties, for example, with regard to strength.

[0015] In a further advantageous embodiment of the crossbeam, the cross walls can be provided with an arcuate cross-section in the area of ​​the respective embossing. An arcuate shape is particularly advantageous with regard to controlling the bulging at the embossing.

[0016] In a further advantageous embodiment of the crossbeam, the embossing depth can be 0.1 to 0.2 times the maximum longitudinal depth of the crossbeam. This embossing depth advantageously combines compliance with deformation limits with good mechanical strength.

[0017] In a further advantageous embodiment of the crossbeam, the crossbeam may have at least two chambers in cross-section, separated by a central wall. The central wall advantageously increases the mechanical load-bearing capacity of the crossbeam, particularly in the longitudinal direction.

[0018] In a further advantageous embodiment of the cross member, the front flange can be provided with a greater vertical extent than the rear flange, preferably 1.3 to 2 times, and particularly preferably about 1.7 times. The front flange can thus offer an advantageously large surface area for force transmission. Furthermore, the front flange can thus advantageously provide an advantageously large surface area for forming connections with other components of a motor vehicle.

[0019] In a further advantageous embodiment of the crossbeam, it can be made of a metal, preferably an aluminum alloy. A metal crossbeam offers advantageous properties with regard to strength and / or durability. An aluminum alloy is particularly advantageous because it allows for a favorable ratio of mechanical strength to weight. Furthermore, aluminum alloys are advantageously corrosion-resistant.

[0020] In a further advantageous embodiment of the cross member, the cross member can be an extruded part. This allows the cross member to be manufactured in a particularly cost-effective manner. This is especially true for high production volumes, as are common in the automotive industry.

[0021] Further advantages, features and details of the invention will become apparent from the following description of preferred embodiments of the invention, as well as from the drawings.

[0022] It shows: Fig. 1: A crash management system with a crossbeam according to the invention in perspective view, Fig. 2a: a sectional view of a crossbeam according to the invention, Fig. 2b: a sectional view of a crossbeam without any markings.

[0023] Identical elements or elements with the same function are provided with the same reference numbers in the figures.

[0024] The Fig. Figure 1 shows a crash management system 100 with a crossbeam 10 according to the invention in a perspective view. The crash management system 100 comprises a crossbeam 10 and two crash boxes 24, the crash boxes 24 being connected to the crossbeam 10 at its edge regions R. The crossbeam 10 extends substantially in a transverse direction Y. In a longitudinal direction X, the crash boxes 24 are arranged on a rear side of the crossbeam 10. Perpendicular to the transverse direction Y and the longitudinal direction X, the crossbeam 10 extends in a vertical direction Z. When installed in a motor vehicle, the transverse direction Y corresponds to the transverse direction of the vehicle, i.e., it is oriented transversely to a direction of travel. In a central region M of the crossbeam 10 located in the transverse direction Y between the edge regions R, the crossbeam 10 has embossings 20, 22, which, in conjunction with the Fig. 2a are evident.

[0025] The Fig. Figure 2a shows a sectional view of a crossbeam 10 according to the invention, wherein the section plane lies in the central region M and is oriented perpendicular to the transverse direction Y. The crossbeam 10 has a closed cross-section with a front flange 12, a rear flange 14, a first transverse wall 16, and a second transverse wall 18. The central region M extends over 0.3 times the length of the rear flange 14 in the transverse direction Y, which is also shown in the Fig. As can be seen in Figure 1. Furthermore, crossbeam 10 has a central wall 17, so that a first chamber 26 and a second chamber 28 are formed inside the crossbeam 10. The length of the front chord 12 in the vertical direction Z is approximately 1.7 times the length of the rear chord 14 in the vertical direction Z.

[0026] In the first transverse wall 16, an indentation 20 is formed, directed towards the interior of the crossbeam 10, and in the second transverse wall 18, an indentation 22 is formed, also directed towards the interior of the crossbeam 10. The indentations 20 and 22 run in a groove-like shape along the transverse direction Y, appearing as a depression on the outside of the crossbeam 10 and as a bulge on the inside. The first transverse wall 16 and the second transverse wall 18 have an arc-shaped profile in the area of ​​the indentations 20 and 22. The indentation depth t is approximately 0.17 times the maximum depth q of the crossbeam 10 in the longitudinal direction X.

[0027] In an upper region 14a of the rear chord 14, a chamfer 15 is formed, wherein the rear chord 14 is chamfered or angled such that the distance between the rear chord 14 and the front chord 12 decreases in the upper region 14a towards the first transverse wall 16. In a lower region 14b of the rear chord 14, a chamfer 15 is formed, wherein the rear chord 14 is chamfered or angled such that the distance between the rear chord 14 and the front chord 12 decreases in the lower region 14b towards the second transverse wall 18.

[0028] An advantage of embossing both transverse walls 16, 18 is that the crossbeam 10 reliably meets tightly specified dimensional tolerances, since undesired bending of the crossbeam 10 about the longitudinal direction X, which can occur if only one of the transverse walls 16, 18 is embossed, is prevented. This works particularly advantageously in conjunction with the chamfers 15, since such undesired bending can also occur in a crossbeam 10 with only a single chamfer 15.

[0029] The crossbeam 10 is manufactured from an aluminum alloy using an extrusion process as an extruded component. Fig. Figure 2b shows a cross-section of a crossbeam 10 as a semi-finished product, without the markings 20, 22 formed in the first transverse wall 16 and the second transverse wall 18 by means of a forming process. Reference sign 10 crossbeams 12 Front strap 14 Rear belt 14a upper section 14b lower section 15 Bevel 16 first transverse wall 17 Middle wall 18 second transverse wall 20 embossing 22 embossing 24 Crashbox 26 first chamber 28 second chamber 100 Crash Management System X Longitudinal direction Y transverse direction Z Altitude direction M Medium range R edge area t Imprint depth l length QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] EP 2 318 237 B1

[0002]

Claims

Crossbeam (10) for a crash management system (100) for a motor vehicle, wherein the crossbeam (10) extends substantially along a transverse direction (Y) and is attachable to a vehicle structure, preferably by means of two crash boxes (24) arranged at a distance from each other on the crossbeam (10), and wherein the crossbeam (10) has a closed cross-section with a front belt (12), a rear belt (14), a first transverse wall (16) and a second transverse wall (18), wherein the transverse walls (16, 18) connect the front belt (12) to the rear belt (14), wherein the front belt (12) is spaced apart from the rear belt (14) in a longitudinal direction (X) and wherein the transverse walls (16, 18) are spaced apart from each other in a vertical direction (Z), characterized in that the transverse walls (16, 18) each have an embossing (20), preferably directed towards the interior of the crossbeam (10), 22) exhibit the markings (20,22) are formed in a central area (M) of the crossbeam (10) in the transverse direction (Y). Crossbeam (10) according to claim 1, characterized in that the embossings (20, 22) are designed such that the rear chord (14) has a chamfer (15) inclined towards the front chord (12) in an upper section (14a) and in a lower section (14b), wherein the chamfers (15) reduce the distance between the rear chord (14) and the front chord (12) in the upper section (14a) towards the first transverse wall (16) and in the lower section (14b) towards the second transverse wall (18). Crossbeam (10) according to claim 1 or 2, characterized in that the embossings (20, 22) are designed as indentations directed into the closed cross-section of the crossbeam (10) or as projections directed outside the closed cross-section of the crossbeam (10). Crossbeam (10) according to one of claims 1 to 3, characterized in that the length of the central region (M) is 0.2 to 0.4 times, preferably 0.25 to 0.35 times, the length of the rear chord (14) in the transverse direction (Y). Crossbeam (10) according to one of the preceding claims, characterized in that the embossings (20, 22) are formed on the outside of the respective transverse wall (16, 18) as a depression and on the inside of the respective transverse wall (16, 18) as a bulge. Crossbeam (10) according to one of the preceding claims, characterized in that the cross walls (16, 18) have an arc-shaped cross-section in the area of ​​the respective embossing (20, 22). Crossbeam (10) according to one of the preceding claims, characterized in that an embossing depth (t) of an embossing (20, 22) is 0.1 times to 0.2 times a maximum depth (q) of the crossbeam (10) in the longitudinal direction (X). Crossbeam (10) according to one of the preceding claims, characterized in that the crossbeam (10) has at least two chambers (26, 28) in cross-section, which are separated by a central wall (17). Crossbeam (10) according to one of the preceding claims, characterized in that the front chord (12) has a greater extent in the vertical direction (Z) than the rear chord (14), preferably 1.3 times to 2 times, particularly preferably about 1.7 times. Crossbeam (10) according to one of the preceding claims, characterized in that the crossbeam (10) is made of a metal, preferably an aluminum alloy. Crossbeam (10) according to one of the preceding claims, characterized in that the crossbeam (10) is an extruded part.

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