Bumper arrangement for a motor vehicle

Abstract

Bumper arrangement for a motor vehicle with a cross member (1), a body element (2), a deformation element (3) arranged between the cross member (1) and the body element (2), and a strut (4) arranged between the cross member and the body element (2) as well as the deformation element (3), characterized in that the strut (4) is firmly connected on the one hand to the cross member (1) and on the other hand to both the body element (2) and the deformation element (3), wherein the strut (4) is connected to an end region (5) of the cross member (1).

Description

The invention relates to a bumper arrangement for a motor vehicle according to the preamble of claim 1.Bumper arrangements of this type for a motor vehicle are known, for example, from DE 10 2013 208 144 A1, DE 10 2008 039 513 A1, U.S. Pat. No. 9,333,928 B2 and JP 6044795 B2. In the first three publications mentioned, a strut is arranged between the respective cross member of the bumper arrangement there and the crash boxes there or a flange element of the crash boxes there, while JP 6044795B2 shows a strut arranged between a cross member of a bumper arrangement and a body element. In motor vehicles with internal combustion engines, bumper arrangements of this type are sufficient in the event of a crash with regard to the transmission of force into the body of the motor vehicle and consequently absorption of the crash energy by the body, since the internal combustion engine contributes there to the transmission of force and the absorption of energy in the event of a crash.However, since motor vehicles with an exclusive electric motor in particular no longer have such an internal combustion engine which can participate in the transmission of power and the absorption of energy in the event of a crash, the new compatibility test MPDB, but also the so-called pole test in the event of a crash, in particular in the event of a frontal crash, requires a higher absorption of energy by the bumper arrangement itself. This requirement can be met by the bumper arrangement being dimensioned to be greater in height and the cross member of such a bumper arrangement being provided with greater rigidity. However, such embodiments would always also be associated with a clear and unacceptable increase in weight of such a bumper arrangement. The same applies to the extension of the installation space of crash boxes for the purpose of increased energy absorption.It is therefore the object of the invention to further develop a bumper arrangement according to the preamble of claim 1 in such a way that the energy absorption capacity of the bumper arrangement is increased and thus it satisfies both the requirements of the new compatibility test MPDB and the requirements of the pole test without having to accept an increase in weight of the bumper arrangement.This object is achieved by a bumper arrangement for a motor vehicle having all the features of claim 1.The bumper arrangement according to the invention for a motor vehicle has a cross member, a body element and a deformation element arranged between the cross member and the body element. In this case, a strut is arranged on the cross member, which strut extends in the direction of the body element and deformation element. The bumper arrangement according to the invention is now distinguished in that the strut is fixedly connected on the one hand to the cross member and on the other hand both to the body element and to the deformation element, wherein the strut is connected to an end region of the cross member. The fixed connection can be understood here preferably as a materially bonded or force-bonded connectionThe bumper arrangement for a motor vehicle according to the invention now provides a bumper arrangement for a motor vehicle which enables a significantly higher energy absorption solely via this bumper arrangement without an unacceptable weight increase thereof than in the bumper arrangements known from the prior art. This increased energy absorption is achieved in that the strut of the bumper arrangement is connected both to the deformation element and to the body element, which are both oriented with their longitudinal extent parallel to the longitudinal extent of the motor vehicle. In the event of a crash, in particular in the event of a frontal crash, the cross member of the bumper arrangement is now deformed in such a way that an energy transmission takes place via the cross member and the strut both into the deformation element and into the body element. As a result, a transmission of the energy introduced into the strut in the event of a crash is not only introduced into the deformation element or the body element. Rather, the crash energy introduced into the strut is partly introduced both into the deformation element and into the body element. This allows a significantly higher energy absorption since the crash energy introduced into the strut acts not only on a single element of the bumper arrangement, but is introduced into two different elements, as a result of which the crash energy is divided into two force paths.It has furthermore proven advantageous that in the event of a crash with a pile-shaped barrier and a central impact via the deformation of the cross member, the body element is activated, wherein the strut then experiences a tensile load and thus acts as a tension strut. It is also advantageous here that the better load distribution means that the coupling regions between the cross member and the deformation element, but also between the deformation element and the body element, are relieved. This also makes it possible to make wall thicknesses, fastening elements or welded connections weaker. On the other hand, in the event of a crash in the outer region of the cross member, the strut can act as a support strut, whereby the rigidity of the entire bumper arrangement is increased, since the strut is connected both to the deformation element and to the body element.According to a first advantageous embodiment of the invention, it is provided that the cross member protrudes beyond both the body element and the deformation element with an end region outwards, pointing away from the motor vehicle. This makes it possible to fasten the strut to this end region of the cross member, which projects beyond the body element and the deformation element. This is important in particular in the event of crashes in the outer region of the cross member, since the strut then provides a higher rigidity and thus a higher resistance of the entire bumper arrangement.Furthermore, it has proven advantageous that the body element is designed as a body side member. Such longitudinal body beams have a very high strength and therefore offer particularly good energy input and transmission properties in the event of a crash.In a further embodiment of the invention, it is provided that the deformation element is designed as a crash box. Crash boxes of this type, which are arranged between the cross member and the body element or the body longitudinal member, have high energy absorption properties, since in the event of a crash they deform very specifically and thus convert a portion of the introduced crash energy into deformation energy.It has proven to be advantageous here for the strut to be connected to the end region of the cross member which projects beyond the body element and the deformation element. This embodiment of the invention enables the strut to act both effectively as a tension strut and as a support strut, and thus both in the case of a pole test or frontal impact in the MPDB test and in the case of a crash in the outer region of the cross member, such as in the case of so-called small overlap tests, the introduced crash energy is introduced well and dissipated with further elements, such as the deformation element, for example.According to a particularly advantageous embodiment of the invention, it is provided that the strut is formed at an angle, wherein a first leg is connected to the end region of the cross member and a second leg is connected to the body element and the deformation element. Such an angled strut is particularly well suited for use in the bumper arrangement according to the invention, since this provides a particular energy absorption and transmission and very good rigidity with increased resistance.It has proven particularly advantageous here that the second leg of the strut bears, in one part, flat against the body element and, in the other part, flat against the deformation element and is also connected to these two elements. This achieves the particular property that a very good connection of the strut to the body element and the deformation element is made possible. As a result, both in the event of a frontal impact and in the event of a load in the outer region of the cross member, the crash energies introduced are processed further in a particularly good manner, such that the deformation element deforms in a predetermined manner in accordance with its task and thus dissipates crash energy, and crash energy is introduced into the body element, on the other hand, which crash energy can likewise then be forwarded and dissipated in the body.In order that the energy can be introduced into the strut in the event of a crash, it is provided according to a particularly advantageous embodiment of the invention that the first leg of the strut is connected by its end to the cross member and forms an angle α not equal to 180° with the latter, wherein the angle α is preferably formed at right angles or acutely. Such a connection of the strut to the cross member of the bumper arrangement ensures a particularly effective introduction of energy into the strut, with the result that the strut can transmit the crash energy to the further elements, such as, for example, the deformation element and the body element. Also, when deforming the strut in the event of a crash, crash energy is already converted accordingly into deformation energy within the strut. This also achieves an increased receiving capacity of the bumper arrangement.In order to achieve an increased stiffness of the strut, it is provided according to a further embodiment of the invention that the strut is profiled in its longitudinal extension and / or in its transverse extension. Such profiles serve on the one hand for the increased rigidity or resistance of the strut in the event of a crash. On the other hand, the energy absorption capacity of the strut is thereby increased once more, since in the event of a crash it can absorb or degrade more crash energy as a result of deformation.In another direction, the embodiment of the invention aims at the strut having beads spaced apart in its longitudinal extent, in particular vertical beads. Such beads have the effect that the strut deforms in a targeted manner depending on the load case or crash test and no negative impairment of the deformation of the deformation element takes place. This protects the further vehicle elements, which also increases the safety of the occupants located in the motor vehicle.In order to further increase the strength or rigidity of the strut, it is provided that the strut is formed from a high-strength steel alloy or aluminum alloy.According to a further embodiment of the invention, it is provided that the cross member is directly connected, in particular welded or screwed, to the deformation element or else is indirectly connected to the deformation element via a coupling or supporting element, such as a bracket, for example. Such an arrangement of the cross member and the deformation element enables a particularly good direct introduction of crash energy into the deformation element, which is specifically deformed in the event of a crash, wherein a portion of the crash energy is already converted into deformation energy of the deformation element and thus further elements of the motor vehicle are protected from damage, whereby the safety of the motor vehicle occupants is also again increased.It can be provided here that the cross member is profiled open or closed or is formed in two parts with a striking plate. Cross members of this type, which are in particular designed as hollow profiles, have already proven themselves in practice and also serve for effective energy dissipation or for energy dissipation in the bumper arrangement according to the invention.In the same direction, the embodiment of the invention aims to design the deformation element as a hollow profile or two-shell steel or sheet metal component. Deformation elements of this type, which are generally designed as crash boxes, are particularly advantageously suitable for absorbing crash energy, since they deform in a predetermined manner in a crash event and thus already break down or absorb a part of the crash energy, whereby the safety of the vehicle occupants is again increased.Further objectives, advantages, features and possible applications of the present invention will become apparent from the following description of exemplary embodiments with reference to the drawings. All features described and / or graphically depicted form the subject matter of the present invention, either alone or in any meaningful combination, also independently of their summary in the claims or their reference back.The following are shown: FIG. 1 : shows an exemplary embodiment of a bumper arrangement according to the invention in a plan view from above, FIG. 2 : a detailed view of the exemplary embodiment of FIG. 1 in a perspective illustration, FIGS. 3 to 9 : various representations of the deformation of the bumper arrangement in a central crash situation in a plan view from above.FIG. 1 shows an exemplary embodiment of a bumper arrangement according to the invention for a motor vehicle. The bumper arrangement has a cross member 1, on which two crash boxes designed as deformation elements 3 are arranged opposite. The cross member 1 extends with its end regions 5 beyond the crash boxes 3 in a direction away from the motor vehicle. In the present exemplary embodiment, the crash boxes 3 are furthermore connected via a flange 9 to body elements 2 in the form of longitudinal body beams. At the end regions 5 of the cross member 1, struts 4 are furthermore arranged, which are formed in an angled manner. The angled braces 4 have a first leg 6 and a second leg 7. They lie flat with the second leg 7 both on the respective longitudinal body member 2 and the respective crash box 3 and are connected to them, wherein the leg 7 is guided through an opening or indentation within the flange 9. In the present exemplary embodiment, the second leg 7 of the strut 4 is connected to the body side member 2 by means of a screw 10, while the second leg 7 likewise bears flat against the crash box 3 in the region thereof and is connected thereto by means of a weld in a materially integral manner. A first leg 6 of the strut 4 abuts with its end opposite the leg 7 against the cross member 3 and is there connected thereto, for example by welding. The first leg 6 of the strut 4 forms an angle α not equal to 180° with the cross member 3, wherein the angle α is formed here approximately at right angles.As can already be seen in the illustration of FIG. 1, the struts 4 are of profiled design and have beads 8 spaced apart in their longitudinal extent.FIG. 2 now shows a detailed illustration of the exemplary embodiment of FIG. 1 in the region of the left end region 5 of the cross member 1. Clearly visible here is the profiled configuration of the strut 4, which has two spaced-apart beads 8 in its longitudinal extent. The strut 4 abuts the end region 5 of the cross member 1 with the end of its first leg 6 opposite the second leg 7 and is there connected to the cross member 1 by means of welding in a materially bonded manner. A cohesive connection of the strut 4 also exists in the region of its first limb 7 with the crash box 3.The crash box 3 is furthermore connected on the one hand to the cross member 1 and on the other hand has a flange 9 with which it can be arranged on a body longitudinal member 2, which is not shown in FIG. 2, however. As can be seen particularly well from the illustration of FIG. 2, however, the crash box 3 is designed as a hollow profile and is provided at the end opposite the cross member 1 with the already described flange 9 in the form of a plate. The crash box 3 here also has beads spaced apart in its longitudinal extension.It can also be clearly seen in the illustration of FIG. 2 that the cross member 1 in this exemplary embodiment is likewise designed as a hollow profile.Furthermore, it can also be seen in the illustration of FIG. 2 that the strut 4 has, in the end region of its second limb 7, a screw 10 by means of which the strut 4 is fastened to the body side member 2, which is not illustrated here.The illustrations in FIGS. 3 to 9 now show the crash situation of a pole test in various steps, wherein the crash takes place centrally with respect to the cross member 1. While FIG. 3 shows the bumper arrangement for a motor vehicle according to FIG. 1 before the crash, FIG. 4 shows the bumper arrangement centrally in the cross member 1 upon impact of an obstacle.In the illustration of FIG. 5, the deformation of the struts 4 can already be clearly seen, wherein the crash boxes 3 are simultaneously deformed and in the process already absorb crash energy. Because the struts 4 are not only connected to the crash box 3 or the body side member 2, the bumper arrangement is constructed to be significantly more resistant and more rigid, so that it can absorb significantly more energy in the event of a crash, since it is connected both to the crash box 3 and to the body side member 2.FIGS. 6 to 9 show further deformation steps of the bumper arrangement, in which both the cross member 1 and the crash boxes 3 and the struts 4 are further deformed. The predetermined deformation of the crash boxes 3 can be clearly seen here, wherein the struts 4 counteract this deformation by their tensile load and thus a major part of the deformation is already absorbed by the tensile load and thus does not have to be absorbed by the crash boxes 3 as deformation energy.Reference Number:1 Cross member 2 body element / body longitudinal member 3 deformation element / crash box 4 strut 5 end region 6 leg 7 leg 8 bead 9 flange 10 screw α angleReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2013 208 144 A1

[0002] DE 10 2008 039 513 A1

[0002] U.S. Pat. No. 9,333,928 B2

[0002] JP 6044795 B2

[0002]

Claims

Bumper arrangement for a motor vehicle, having a cross member (1), a body element (2), a deformation element (3) arranged between the cross member (1) and the body element (2), and a strut (4) arranged between the cross member and the body element (2) and also the deformation element (3), characterized in that the strut (4) is fixedly connected on the one hand to the cross member (1) and on the other hand both to the body element (2) and to the deformation element (3), the strut (4) being connected to an end region (5) of the cross member (1).Bumper arrangement according to Claim 1, characterized in that the cross member (1) projects beyond both the body element (2) and the deformation element (3) with its end region (5) outwards, pointing away from the motor vehicle.Bumper arrangement according to one of the preceding claims, characterized in that the body element (2) is designed as a body side member.Bumper arrangement according to one of the preceding claims, characterized in that the deformation element (3) is designed as a crash box.Bumper arrangement according to one of the preceding claims, characterized in that the strut (4) is designed as a tension strut and / or as a support strut.Bumper arrangement according to one of the preceding claims, characterized in that the strut (4) is formed at an angle, a first limb (6) being connected to the end region (5) of the cross member (1) and a second limb (7) being connected to the body element (2) and to the deformation element (3).Bumper arrangement according to Claim 6, characterized in that the second limb (7) of the strut (4) bears on one part against the body element (2) and on the other part against the deformation element (3).Bumper arrangement according to Claim 6 or 7, characterized in that the first limb (6) of the strut (4) is connected by its end to the cross member (3) and forms an angle (α) with the latter of less than or equal to 180°.Bumper arrangement according to one of the preceding claims, characterized in that the strut (4) is profiled in its longitudinal extent and / or in its transverse extent.Bumper arrangement according to one of the preceding claims, characterized in that the strut (4) has beads (8) spaced apart in its longitudinal extent.Bumper arrangement according to one of the preceding claims, characterized in that the strut (4) is welded or screwed to the cross member (1) and / or the body element (2) and / or the deformation element (3).Bumper arrangement according to one of the preceding claims, characterized in that the cross member (1) is welded or screwed directly to the deformation element (3) or else is connected indirectly to the deformation element (3) via a coupling or supporting element.

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