Crossmember for a bumper system of a motor vehicle, bumper system with such a crossmember, and motor vehicle with such a bumper system

Abstract

The invention relates to a cross member (125) for a bumper system (115) of a motor vehicle (100), which is formed in two parts from a profile (205) open on one side in cross-section and a closing plate (210) that at least partially closes the profile (205), wherein a stiffening element (220) is arranged on a central longitudinal section (215) and within the cross member (125), which is attached to the profile (205) and oriented in the direction of the closing plate (210), wherein the stiffening element (220) has a notch (400, 900, 1000, 1005, 1010, 1200, 1300, 1400, 1405) which is designed and arranged on the stiffening element (220) such that in a frontal collision on the central longitudinal section (215) of the cross member (125) flanks (405, 410) of the notch (400, 900, 1000, 1005, 1010, 1200, 1300, 1400, 1405) come into contact with each other at least section by section in order to increase the bending stiffness of the crossbeam (125),and in a frontal collision with lateral overlap, the stiffening element (220) is locally weakened by the notch (400). Furthermore, the invention relates to a bumper system (115) for a motor vehicle (100) and a motor vehicle (100).

Description

[0001] The invention relates to a cross member for a bumper system of a motor vehicle. Furthermore, the invention relates to a bumper system for a motor vehicle. Furthermore, the invention relates to a motor vehicle with at least one such bumper system. The bumper system can advantageously be used on the front side or front end of the motor vehicle.

[0002] In general, vehicles are known to incorporate various structures to improve the vehicle's behavior in different types of collision or impact. The behavior of a vehicle and its various structures, arrangements, and components in the event of a collision can be evaluated using a wide variety of simulations and tests. Bumper systems, in particular, are known as impact-damaging devices that absorb and dissipate impact energy in the event of an impact in such a way that the vehicle's supporting structure behind it remains as undamaged as possible. A bumper system, also called a crash management system (CMS for short), comprises a cross member, usually two deformation boxes, and optional longitudinal members for connection to the vehicle structure.The energy resulting from an impact is absorbed by the cross member, transmitted, and absorbed by the deformation boxes. In other words, the cross member primarily serves to transmit force to the deformation boxes, where the energy can be absorbed. It is conceivable that the vehicle could include additional load distribution frames or similar structures to dissipate forces.

[0003] As part of a full-vehicle test, one of the tests performed is an analysis of an MPDB (Mobile Offset Progressive Deformable Barrier). This involves driving a test vehicle into a mobile, progressive, deformable obstacle, also known as a barrier, mounted on an oncoming 1400 kg car. The test simulates a frontal collision between the test vehicle and a typical mid-size family car. Among other things, the analysis of a barrier imprint after the impact allows for assessing the risk of head, neck, chest, and abdominal injuries to vehicle occupants. In the MPDB frontal crash load case, achieving the most homogeneous barrier imprint possible is crucial for the vehicle's classification, particularly for an NCAP rating.Due to the sweep of the vehicles and the resulting installation space situation, it is desirable to achieve a uniform force-displacement curve across the entire vehicle width.

[0004] Furthermore, the so-called "pile center" load case is analyzed as part of the complete vehicle testing. This test is conducted to verify the vehicle's safety in the event of a pole impact. The "pile center" load case refers to an impact with a pole in the center of the vehicle. The pole impact test evaluates the structural integrity and safety of the vehicle. The analysis of the "pile center" load case includes the evaluation of various factors, such as vehicle deformation, the impact on the occupants, and the effectiveness of the safety devices.

[0005] In the aforementioned tests for full-vehicle testing, there is a conflict of objectives regarding the flexural rigidity of the cross member. While the MPDB load case requires the most uniform barrier footprint possible, which consequently requires sections with both softer and stiffer bending properties across the vehicle width, the cross member for the "pile center" load case must be as rigid as possible, especially in the center of the vehicle.

[0006] WO 2023 / 232 977 A1 relates to a crash management system for a motor vehicle, wherein the crash management system comprises a cross member for connection to a body structure of the motor vehicle.

[0007] JP 2005 - 297 857 A proposes a bumper with lightweight side panels. A reinforcement structure allows for efficient load distribution along the bumper's longitudinal direction. Based on the prior art, the object of the invention is to provide a cross member for a bumper system of a motor vehicle that resolves this conflict of objectives. This object is achieved by a cross member for a bumper system according to claim 1, a bumper system for a motor vehicle according to claim 12, and a motor vehicle according to claim 14. Subclaims represent preferred embodiments.

[0008] According to a first aspect of the invention, a cross member for a bumper system of a motor vehicle is formed in two parts from a profile which is open on one side in cross section and a closing plate which at least partially closes the profile, wherein a stiffening element is arranged on a central longitudinal section and within the cross member, which stiffening element is fastened to the profile and is aligned in the direction of the closing plate, wherein the stiffening element has a notch which is designed and arranged on the stiffening element in such a way that in the event of a frontal collision at the central longitudinal section of the cross member, flanks of the notch come into contact with one another at least in sections in order to increase the flexural rigidity of the cross member, and in the event of a frontal collision with lateral overlap, the stiffening element is locally weakened by the notch.The notch is arranged on a side of the stiffening element facing the strike plate and guide sections are arranged on the notch to guide the flanks of the notch during a relative movement to each other.

[0009] Due to its rib-shaped design and arrangement in the central longitudinal section of the profile, the stiffening element fundamentally improves the dimensional rigidity of the cross member. The stiffening element is fastened to the profile in the interior of the cross member. The stiffening element is preferably a stiffening plate that is arranged perpendicular to the striking plate. Alternatively, the stiffening element is a stiffening plate that is arranged at an angle to the striking plate. Accordingly, the stiffening element is arranged perpendicularly or at an angle to the connecting web of the profile and is fastened thereto. "Inclined" in this context means that the stiffening element, when the bumper system is assembled, is arranged at an angle to a horizontal plane and is fastened to the profile. In the initial state of the cross member, the stiffening element is arranged at a distance from the striking plate and does not come into contact with the striking plate.Preferably, the stiffening element is connected to the profile by a material fit, for example, by gluing or welding. Alternatively or additionally, the stiffening element is connected to the profile by a form-fitting connection, for example, by means of a screw connection. The cross-sectional geometry of the stiffening element fulfills different functions for the "pile-center" load case, in which a pile intrudes into the cross member, and for the MPDB load case, in which a barrier impacts the vehicle laterally offset.

[0010] The term "stiffening element" primarily refers to the element's function in the "pile-center" load case. Accordingly, a stiffening mechanism is implemented by means of the stiffening element for the "pile-center" load case. During the deformation of the cross member due to the impact of the pile on the central longitudinal section, the stiffening element deforms in such a way that it wraps around the pile, closing or at least reducing the notch as the notch flanks move toward each other. At the point in time at which the notch flanks come into contact, the area moment of inertia or section modulus of the stiffening element and thus also of the profile increases, thereby improving the deformation behavior of the cross member for the "pile-center" load case. Thus, deflection of the cross member in the "pile-center" load case is made more difficult and the bending stiffness of the cross member is increased.The stiffening mechanism is only triggered in the "pile-to-center" load case. The central longitudinal section is arranged on a central axis of the bumper system. The central longitudinal section of the cross member is preferably designed with mirror symmetry.

[0011] In contrast, in the MPDB load case, the countermovement of the crossbeam causes the notch of the stiffening element to become larger compared to the "pile center" load case, resulting in a lower area moment of inertia or section modulus when the movement changes to 3-point bending. The notch forms a predetermined buckling point in the MPDB load case. During the first movement of the crossbeam in the MPDB load case (cantilevered beam), the notch is widened or enlarged in order to offer less resistance in the second movement, namely 3-point bending, and to promote buckling of the crossbeam on the center axis of the crossbeam, i.e., at Y0. Thus, contrary to its literal meaning, the stiffening element weakens the crossbeam in the MPDB load case and realizes targeted deformation behavior in the MPDB load case.

[0012] The stiffening element with one or more notches enables, on the one hand, a flexible behavior of the cross member for the MPDB load case and, on the other hand, a rigid behavior of the cross member in the “pile center” load case.

[0013] Of course, it is conceivable for the stiffening element to have more than one notch. The stiffening element is preferably designed with mirror symmetry, so that the notches are arranged and formed mirror-inverted with respect to a central axis.

[0014] By arranging the stiffening element within the cross member, the stiffening mechanism can be implemented in a space-neutral manner.

[0015] The cross member can be a hybrid cross member. The cross member can consist of several components, which in turn can be made of different materials. The strike plate is preferably made of metal, while the profile is made of a fiber-reinforced plastic or metal.

[0016] The profile may have sections with different cross-sectional configurations and / or different mechanical properties in the longitudinal direction of the cross member. The profile is coupled to the strike plate. The strike plate may have a substantially constant thickness along its longitudinal extent.

[0017] The profile is preferably designed as a hat profile. The hat profile is formed in cross-section by two legs that are connected to each other via a connecting web on the rear side of the profile. The connecting web thus borders the legs. The connecting web is designed to be connected or coupled to deformation boxes on its side facing away from the legs.

[0018] The profile and the stiffening element have a concave contour at the central longitudinal section, arranged at least partially on a front side of the profile with respect to the forward direction of travel of the motor vehicle. The concave contour at the central longitudinal section of the cross member or the profile and the stiffening element is each a partially circular depression in the X-direction of the bumper system or the motor vehicle, wherein the concave contour is designed to accommodate an obstacle in the form of a post in the event of a frontal collision in the "post-center" load case, thereby enabling even force introduction and distribution.

[0019] The concave shape located at the front of the vehicle's central longitudinal section, in the forward direction of travel, creates a predetermined bending point on the profile, which ensures targeted deformation behavior of the cross member in the "pile center" load case. This improves the NCAP result for the "pile center" load case because the cross member is locally stiffened, and the vehicle can be classified as safer. At the same time, a homogeneous barrier imprint can be achieved for the MPDB load case, since the design of the cross member does not negatively influence the deformation behavior in the MPDB load case.

[0020] Optionally, the profile can have an additional predetermined bending point on a side facing away from the strike plate. Furthermore, the strike plate can also have a predetermined bending point in the area of ​​the central longitudinal section of the cross member. This allows the deformation behavior of the cross member to be further improved or better controlled in the "pile center" and MPDB load cases.

[0021] The respective target bending point is preferably located on the center axis. This ensures that, particularly in a frontal collision with lateral overlap, the deformation behavior of the cross member is essentially identical regardless of the vehicle side. In the "pile-center" load case, this also enables essentially symmetrical deformation behavior of the cross member.

[0022] The concave contour is preferably designed to complement the outer geometry of a pile for the "pile center" load case. The pile in this load case typically has a diameter of 350 mm. Accordingly, the concave contour of the profile has a radius of at least 175 mm, at least in some sections, to create the largest possible contact area in the event of a frontal impact. The concave contour of the profile is thus designed as a negative profile of a pile for the "pile center" load case.

[0023] In a further development of the invention, the stiffening element has a first section coupled to the profile, a second section coupled to the profile, and a recess arranged between the two sections. The sections and the recess are arranged on a side of the stiffening element facing the profile and thus on a side of the stiffening element facing away from the locking plate. The stiffening element is connected or coupled via the two sections. The two sections of the stiffening element can be connected to the profile in a form-fitting and / or material-fitting manner. The recess enables the stiffening element to deform as desired during the "pile-center" load case, in particular to close the respective notch, without creating constraints on the profile and / or the stiffening element.

[0024] In one embodiment, the notch is arranged in the region of the recess of the stiffening element on a side of the stiffening element facing the profile. Accordingly, the notch is arranged on a side of the stiffening element facing away from the strike plate.

[0025] The notch is located on a side of the stiffening element facing the strike plate. Accordingly, the notch is located on a side of the stiffening element facing away from the connecting web of the profile.

[0026] A notch arranged on an edge of the stiffening element can be designed as a V-notch, the flanks of which are preferably arranged at an acute angle to each other. Alternatively, the notch can be designed in the form of a cutout, which also has tapered inner edges, to create a predetermined breaking point in the MPDB load case, allowing the stiffening element to tear open in the corner area of ​​the notch, and to achieve the aforementioned stiffening effect in the "pile center" load case by deforming the flanks towards each other and pressing them together.

[0027] If only a single notch is provided, it is located on the central axis or in the center of the stiffening element. If two notches are provided, they are either both located on the central axis or both equally spaced to the left and right of the central axis to ensure symmetrical deformation behavior of the stiffening element and the cross member. This also applies analogously to three or more notches.

[0028] Guide sections are arranged on the notch to guide the notch flanks during relative movement. These guide sections prevent shearing of the two notch flanks when the stiffening element is subjected to bending loads and the notch closes when the crossbeam bends during the "pile-center" load case. The guide sections guide the notch flanks during their relative movement, particularly when the notch flanks close, and prevent the flanks from buckling or shearing against each other.

[0029] The guide sections, which in their simplest form are guide plates or guide rails, ensure that the notch flanks are in contact with each other. This functionality is based on the principle of a sliding door, whereby the notch flanks' degrees of freedom are limited by the guide sections. Due to the guide sections, the notch flanks can only move toward or away from each other.

[0030] The guide sections can, for example, be assigned to one of the flanks of the notch or be fastened or molded in the region of this flank and extend accordingly in the direction of the opposite flank. In other words, the guide sections are arranged on one side of the notch. Alternatively, guide sections can be aligned in opposite directions to one another, with at least one guide section being assigned to one flank and at least one further guide section being assigned to the respective opposite flank of the same notch. The guide sections can be arranged on the stiffening element in a material-to-material and / or form-fitting manner. In the case of multiple notches, only one notch, multiple notches, or all notches can have guide sections.

[0031] In a further embodiment, the notch is formed as an opening in the stiffening element. In other words, the notch can be arranged at a distance from a side edge of the stiffening element. For optimal deformation behavior for the respective load case, it is advantageous to design such a notch in a diamond-shaped or substantially diamond-shaped manner in order to achieve both a local weakening of the stiffening element in the MPDB load case and a contact of the notch flanks in the "pile center" load case.

[0032] It is also conceivable to provide several notches, each designed as a perforation. The perforations are preferably located at points on the stiffening element where the greatest forces act in the MPDB load case, so that the cross member can be weakened for the respective load case. At the same time, the perforations are designed and arranged in such a way that the flanks or inner surfaces of the perforations are pressed together by the acting forces in the "pile-center" load case and may come into contact with one another.

[0033] In a further development of the invention, the stiffening element has embossing. Embossing is particularly advantageous for a sheet-metal stiffening element, where the sheet metal is deformed by mechanical or hydraulic forces to create specifically shaped depressions or elevations. This process is referred to as embossing or deformation. The embossings are elevations and / or depressions in the transverse direction of the stiffening element, thereby improving the stiffening element's rigidity. The embossing prevents the stiffening element or rib from bulging under load.

[0034] It is also conceivable to provide more than one stiffening element which realizes the above-mentioned functions and advantages. The stiffening elements can be arranged parallel to one another in the interior of the cross member. The stiffening elements can be of identical design. If, for example, two stiffening elements are arranged in the interior of the cross member, they can be arranged parallel to one another in the longitudinal direction and at a distance from one another in the vertical direction if they are arranged or aligned perpendicular to the profile, for example. If the stiffening elements are arranged obliquely to the striking plate or the connecting web of the profile, they can be arranged mirror-inverted to one another with respect to a longitudinal extent, in particular a longitudinal axis, of the profile.Accordingly, the stiffening elements are arranged substantially parallel and spaced apart from one another in the longitudinal direction, whereby the distance between the stiffening elements can increase or decrease in the longitudinal direction of the vehicle. Of course, it is also conceivable to provide more than two stiffening elements. When the term "one stiffening element" is used in the context of this invention, this is expressly understood to mean that the cross member has at least one stiffening element. Accordingly, the cross member can also have two or more than two stiffening elements.

[0035] According to a second aspect of the invention, a bumper system of a motor vehicle comprises a cross member according to the first aspect of the invention, wherein the cross member is arranged transversely to the longitudinal axis of the motor vehicle.

[0036] Accordingly, the bumper system comprises a cross member arranged transversely to the longitudinal axis of the motor vehicle and coupled to two deformation boxes aligned parallel to the longitudinal axis of the motor vehicle, wherein the cross member is formed in two parts from a profile that is open on one side in cross section and a closing plate that at least partially closes the profile, wherein a stiffening element is arranged on a central longitudinal section and within the cross member, which stiffening element is fastened to the profile and aligned in the direction of the closing plate, wherein the stiffening element has a notch that is designed and arranged on the stiffening element such that, in the event of a frontal collision, flanks of the notch at least partially come into contact with one another on the central longitudinal section of the cross member in order to increase the flexural rigidity of the cross member,and in a frontal collision with lateral overlap, the stiffening element is locally weakened by the notch.

[0037] The bumper system is designed to absorb forces from a frontal collision. The bumper system is also considered the vehicle's crash management system and is connected directly or indirectly, particularly via the deformation boxes, to the vehicle's supporting structure. The bumper system is designed to absorb forces from a collision. The cross member is arranged essentially perpendicular to the direction of travel or the longitudinal axis of the vehicle, or extends transversely across a large part of the vehicle's width.

[0038] The cross member is preferably arranged on two deformation boxes aligned parallel to the longitudinal axis of the motor vehicle. In other words, the cross member is coupled to the deformation boxes. The deformation boxes are arranged at equal distances from a center axis of the bumper system, which preferably lies on the longitudinal axis of the motor vehicle. The bumper system is designed with mirror symmetry.

[0039] Preferably, the strike plate is arranged facing forward in the longitudinal direction of the vehicle. In other words, the strike plate is directed forward in the forward direction of travel of the vehicle. Thus, the cross member can be mounted with the strike plate facing forward or outward in the forward direction of travel.

[0040] According to a third aspect of the invention, a motor vehicle comprises a bumper system according to the second aspect of the invention. The motor vehicle comprises a supporting structure and a chassis, wherein, in the direction of travel, in front of and behind the supporting structure, there are bumper systems or devices for impact absorption, at least one of which is designed as a bumper system according to the second aspect of the invention. In one exemplary embodiment, both bumper systems are designed as bumper systems according to the second aspect of the invention.

[0041] The above definitions as well as explanations of technical effects, advantages, and advantageous embodiments of the cross member according to the first aspect of the invention also apply mutatis mutandis to the bumper system according to the second aspect of the invention and to the motor vehicle according to the third aspect of the invention, and vice versa. It is understood that the features mentioned above and those to be explained below can be used not only in the respective combinations specified, but also in other combinations or on their own, without departing from the scope of the present invention.

[0042] The invention will now be described in more detail with reference to the accompanying drawings, in which: Fig. 1 is a highly schematic plan view of a motor vehicle according to the invention with a bumper system according to the invention according to a first embodiment; Fig. 2 a first schematic plan view of the bumper system according to the invention according to Fig. 1 with a cross member according to the invention in an initial state; Fig. 3 a highly schematic cross-sectional view of the bumper system according to the invention according to Fig. 1 and Fig. 2 in the initial state; Fig. 4 a schematic plan view of the cross member of the bumper system according to the invention - shown only partially here - according to Fig. 1 to Fig. 3 in the initial state; Fig. 5 a first highly schematic plan view of the bumper system according to the invention - shown only partially here - according to a second embodiment in the initial state; Fig. 6 a second highly schematic plan view of the bumper system according to the invention - shown only partially here - according to Fig. 5 during a frontal collision in the “pile-center” load case; Fig. 7 a third highly schematic plan view of the bumper system according to the invention - shown only partially here - according to Fig. 5 and Fig. 6 during a frontal collision with side overlap; Fig. 8 is a highly schematic plan view of the bumper system according to the invention - shown only partially here - according to a third embodiment in the initial state; Fig. 9 is a highly schematic plan view of a stiffening element of the cross member according to the invention according to a fourth embodiment; Fig. 10 is a highly schematic plan view of a stiffening element of the cross member according to the invention according to a fifth embodiment; Fig. 11 is a highly schematic plan view of a stiffening element of the cross member according to the invention according to a sixth embodiment; Fig. 12 is a highly schematic plan view of a stiffening element of the cross member according to the invention according to a seventh embodiment; Fig. 13 is a highly schematic plan view of a stiffening element of the cross member according to the invention according to an eighth embodiment; Fig. 14 a schematic plan view of the cross member of the bumper system according to the invention - shown only partially here - according to a ninth embodiment in the initial state; Fig. 15 a schematic view of the cross member according to the invention - shown only partially here - according to Fig. 14 to illustrate the design of the stiffening element; Fig. 16 a detailed perspective view of a notch of the stiffening element according to Fig. 14 and Fig. 15 to illustrate the design of guide sections; Fig. 17 is a schematic perspective view of a stiffening element of the cross member according to the invention according to a tenth embodiment; Fig. 18 a schematic plan view of the stiffening element according to Fig. 17; and Fig. 19 illustrates a schematic perspective view of a stiffening element of the cross member according to the invention according to an eleventh embodiment, wherein identical or similar components are provided with the same reference numerals.

[0043] After Fig. 1, a motor vehicle 100 is shown that has a support structure 105 and four wheels 110, two wheels 110 each on a front axle and a rear axle, or on the left and right sides of the vehicle. At the front of the motor vehicle 100, a bumper system 115 according to the invention is connected to the support structure 105. A bumper system can also be arranged at the rear of the motor vehicle 100, although this will not be described in more detail here. In any case, it is conceivable that the bumper system at the rear of the motor vehicle 100 is designed analogously to the bumper system 115 described below and is connected to the support structure 105. When traveling forward, the motor vehicle 100 moves in the direction of travel 120. The direction of travel 120 is thus to be understood as the forward direction of travel of the motor vehicle 100. The bumper system 115 according to the invention comprises, according to Fig. 1 to Fig. 4 shows a cross member 125 according to the invention arranged transversely to the direction of travel 120 of the motor vehicle 100, which is connected to the support structure 105 of the motor vehicle 100 via two deformation boxes 130, 135 coupled thereto. The deformation boxes 130, 135 are mirrored about a longitudinal axis 140 of the motor vehicle 100. The bumper system 115 is mirror-symmetrical to a central axis 200, which in this case lies on the longitudinal axis 140 of the motor vehicle 100. The bumper system 115 is part of a crash management system of the motor vehicle 100 (not shown in detail here).

[0044] After Fig. 2 in combination with Fig. 3, the cross member 125 is formed in two parts from a profile 205 which is open on one side in cross section and a locking plate 210 which partially closes the profile 205. The profile 205 has Fig. 3 has two legs 300, 305, which are integrally connected to one another via a connecting web 310. The cross member 125 is coupled to the deformation boxes 130, 135 via the connecting web 310. In this sense, the profile 205 is designed as a hat profile. The profile 205 and the strike plate 210 are each made of metal.

[0045] The locking plate 210 is arranged facing forward in the direction of travel 120 or the forward direction of travel of the motor vehicle 100. The profile 205 has a concave contour 225 on a front side of the central longitudinal section 215 relative to the direction of travel 120. In the initial state of the cross member 125 according to Fig. 2 to Fig. 4, the locking plate 210 runs in the area of ​​the concave contour 225 at a distance from the profile 205. The concave contour 225 forms a predetermined bending point for the locking plate 210, which ensures that the cross member 125 in the load case "pile center", i.e. in the case of a central frontal collision of the cross member 125 with the Fig. 6, the desired, particularly symmetrical, deformation behavior for this load case is realized.

[0046] In the Fig. 2 as well as 4 to 8 and 15 to 17 illustrate that a stiffening element 220 is arranged on a central longitudinal section 215 of the cross member 125, in particular of the profile 205, and within the cross member 125. This stiffening element 220 is fastened to the connecting web 310 of the profile 205 and is aligned parallel to the legs 300, 305 of the profile 205 in the direction of the striking plate 210. The stiffening element 220 is a sheet metal rib or stiffening plate that is integrally connected to the profile 205. The stiffening element 220 is aligned perpendicular to the striking plate 210. Alternatively, the stiffening element 229 can be arranged obliquely to the striking plate 210. In the initial state, the stiffening element 220 does not come into contact with the striking plate 210.

[0047] As in Fig. 4, the stiffening element 220 has a V-shaped notch 400 lying on the central axis 200 and arranged on a side of the stiffening element 220 facing the striking plate 210, which is designed and arranged on the stiffening element 220 in such a way that in the event of a frontal collision at the central longitudinal section 400 of the cross member 125 (load case “pile center”), flanks 405, 410 of the notch 400 come into contact with one another at least in sections in order to increase the flexural rigidity of the cross member 125, and in the event of a frontal collision with lateral overlap (MPDB load case), the stiffening element 220 is locally weakened by the notch 400.

[0048] The deformation behavior of the cross member 125 is shown in the second embodiment according to Fig. 5 to Fig. 7. The stiffening element 220 shown here has, instead of a concave contour, two tappets 500, 505, with a first tappet 500 to the left and a second tappet 505 to the right of the central axis 200 and aligned in the direction of the striking plate 210. A recess 510 is provided between the tappets 500, 505, at which the notch 400 is arranged, analogously to the first exemplary embodiment, on the side of the stiffening element 220 facing the striking plate 210. Furthermore, a predetermined bending point 515, 520 is provided on the profile 205 and on the striking plate 210 on the central axis 200, which positively influence the desired deformation behavior of the cross member 125. Furthermore, the stiffening element 220 has two sections 525, 530 that are integrally connected to the profile 205 and a recess 535 arranged between the two sections 525, 530.Accordingly, the stiffening element 220 is H-shaped in the present view, wherein the recesses 510, 535 allow unhindered deformation of the stiffening element 220 without creating constraints in the stiffening element 220 or in the profile 205.

[0049] While in Fig. 5 shows the initial state of the bumper system 115, Fig. 6 shows the state at the beginning of the "pile center" load case. When pile 600 impacts the central longitudinal section 215 of the locking plate 210, located on the central axis 200, a force acts on the cross member 125 in the direction of arrow 605. In the "pile center" load case, a path with lower resistance is initially bridged before the locking plate 210 contacts the plungers 500, 505 of the stiffening element 220, and the forces are transmitted via the stiffening element 220 into the profile 205. This ensures that the load path remains uninterrupted and does not break off.

[0050] As a result of the force acting in the "pile center" load case, the stiffening element 220 is deformed such that the flanks 405, 410 of the notch move toward each other, thus closing the notch 400. This increases the area moment of inertia or the section modulus of the cross member 125 and consequently makes deflection of the cross member 125 more difficult compared to other load cases, especially the MPDB load case. The direction of force flow is in Fig. 6 is illustrated by the small arrows on the stiffening element 220.

[0051] The MPDB load case is in Fig. 7 illustrates that in the event of a frontal collision with lateral overlap, here on the left side of the vehicle, the cross member 125 deforms as a result of the force acting in the direction of the arrow 700.

[0052] When the cross member 125 is deformed on one side, only one of the plungers, here the left plunger 500, is loaded by the strike plate 210, causing the stiffening element 220 to behave as a cantilevered beam. The load widens or enlarges the notch 400. Consequently, the notch 400 opens. Subsequently, a three-point bending of the stiffening element 220 occurs, which promotes a buckling of the left part of the cross member 125 at the center axis 200. The notch 400 thus locally weakens the cross member 125 in the MPDB load case.

[0053] In Fig. 8 shows an alternative embodiment of the bumper system 115 in an initial state. This embodiment is a combination of the first and second embodiments, wherein the side of the stiffening element 220 facing the striker plate 210 is arranged analogously to the first embodiment according to Fig. 1 to Fig. 4 and wherein the side of the stiffening element 220 facing the profile 205 is designed analogously to the second embodiment according to Fig. 5 to Fig. 7. To avoid repetition, reference is made to the relevant sections of the text. The deformation behavior of the bumper system 115 according to Fig. 8 is also identical to the previous embodiments for the MPDB and "pile center" load cases, which is why a representation of the load cases or the deformation behavior of the cross member 125 is omitted. Reference is made to the above explanations.

[0054] The Fig. 9 to 13 illustrate further possible embodiments of the stiffening element 220, wherein only differences from the previous embodiments according to Fig. 1 to Fig. 8 is discussed.

[0055] The stiffening element 220 according to Fig. 9 is essentially identical to the embodiment according to Fig. 8. Here, in the region of the second recess 535, i.e., on a side of the stiffening element 220 facing the profile 205, a further notch 900 is additionally arranged, which, together with the first notch 400, lies on the central axis 200. In the present case, the further notch 900 is partially circular and is arranged on a side of the stiffening element 225 opposite the notch 400.

[0056] The stiffening element 220 according to Fig. 10 is essentially identical to the embodiment according to Fig. 5 to Fig. 7. Here, in the area of ​​the second recess 535, i.e., on a side of the stiffening element 220 facing the profile 205, three additional notches 1000, 1005, 1010 are additionally provided, wherein two of the additional notches 1000, 1005 are arranged in the corners of the second recess 535, i.e., in the transition region to the respective section 525, 530 of the stiffening element 220, and wherein the third additional notch 1010 lies, together with the first notch 400, on the central axis 200. In the present case, the additional notches 1000, 1005, 1010 are each partially circular.

[0057] The stiffening element 220 according to Fig. 11 is essentially identical to the embodiment according to Fig. 5 to Fig. 7. The difference here is that the notch 400 simultaneously forms the first recess 510 between the tappets 500, 505. This allows the geometry of the stiffening element 220 to be simplified.

[0058] The stiffening element 220 according to Fig. 12 is essentially identical to the embodiment according to Fig. 8. Instead of a notch on a side or edge of the stiffening element 220 facing the strike plate 210, four notches 1200 are arranged in the form of a diamond-shaped opening, evenly spaced along the central axis 200. The number of notches can be adjusted as required, which is particularly possible with the further embodiment according to Fig. 13. Here, a notch 1300 in the form of a single diamond-shaped opening can be arranged mirror-symmetrically on the central axis 200.

[0059] In the ninth embodiment according to the Fig. 14 to 16, the stiffening element 220 has seven notches 400, 1400, 1405, wherein the central notch 400, analogous to the embodiment according to Fig. 4. To the left and right of the central axis 200, three further notches 1400, 1405 are arranged at a distance from the central axis 200. The stiffening element 220 is mirror-symmetrical. The behavior of all notches 400, 1400, 1405 is essentially identical in the respective load case. In the "pile center" load case, the flanks 405, 410 of the respective notch 400, 1400, 1405 move towards each other, as indicated by the arrows 1600, 1605 in Fig. 16, until they come into contact with one another, thus increasing the area moment of inertia of the stiffening element 220. In the MPDB load case, the flanks 405, 410 of the respective notch 400, 1400, 1405 move in the opposite direction, thus increasing the notch or the distance between the flanks 405, 410, whereby the stiffening element 220 is locally weakened in order to ensure the deformation behavior of the stiffening element 220 and the cross member 125 desired for the MPDB load case.

[0060] In this embodiment, as shown in the plan view of the central longitudinal section 215 of the profile 205 according to Fig. 15 and the detailed representation of the notch 400 according to Fig. 16, guide sections 1500, 1505 are provided at each notch 400, 1400, 1405, wherein a first guide section 1500 is arranged above and a second guide section 1505 is arranged below the notch 400, 1400, 1405 or the stiffening element 220. The respective notch 400, 1400, 1405 is thus arranged between two associated guide sections 1500, 1505. The guide sections 1410, 1415 are preferably formed from the same material as the stiffening element 220, in particular from sheet metal, so that a material-to-material connection, in particular a welded connection, between the guide sections 1500, 1505 and the sheet metal of the stiffening element 220 is possible. The guide sections 1410, 1415 are each assigned to the second flank 410 of the notch 400, 1400, 1405 and extend with the guide flanks substantially parallel to the stiffening element 220.

[0061] The guide sections 1500, 1505 are curved and serve to prevent the flanks 405, 410 of the respective notch 400, 1400, 1405 from shearing off relative to one another when the stiffening element 220 is subjected to bending loads, particularly in the "pile center" load case, when the flanks 405, 410 are pressed against one another. In other words, the guide sections 1500, 1505 ensure that the flanks 405, 410 firstly come into contact with one another and secondly are held in this position to achieve the desired stiffening effect. The guide sections 1500, 1505 can also be formed by a one-piece guide element.

[0062] In the illustration according to Fig. 15 further illustrates that the stiffening element 220 is welded to the profile 205 at both ends in the longitudinal direction of the profile 205 via shoes 1510. The shoes 1510 improve the stiffness of the stiffening element 220, particularly during deformation in the described load cases.

[0063] In the Fig. Two further exemplary embodiments are shown in Figures 17 to 19. The stiffening element 220 is therefore essentially identical to the exemplary embodiment according to Fig. 14 to Fig. 16. The difference here is that the stiffening element 220 has, instead of guide sections, embossments 1700, which are designed alternately as a depression and as a protrusion on the respective side surface along the longitudinal extent of the stiffening element 220. In other words, each protrusion on one side surface of the stiffening element 220 is simultaneously a depression on the other side surface of the stiffening element 220. Due to the embossments 1700, the stiffening element 220 is stiffer than without embossments. By means of the embossments 1700, bulging of the stiffening element 220 in the Z direction, i.e., transversely to the longitudinal extent of the stiffening element 220, is prevented or at least significantly impeded under load. Furthermore, reference is made to the explanations according to Fig. 14 to Fig. 16.

[0064] In the embodiment according to Fig. 17 and Fig. 18, the embossments 1700 on the side surfaces of the stiffening element 220 are formed as self-contained, isosceles triangles with rounded edges. In the embodiment according to Fig. 19, the embossments 1700 are also triangular, but the embossments 1700 are open toward the underside of the stiffening element 220, toward the profile 205, or on the side facing away from the notches 400, 1400, 1405. As a result, the stiffening element 220 rests on the connecting web of the profile 205 in a serpentine shape, at least in sections.

[0065] It is conceivable to combine the embodiments described herein. For example, the embodiment according to the Fig. 14 to 16 with the embodiment according to Fig. 17 or Fig.19. Furthermore, the design and geometry of the stiffening element 220 can be adapted as desired to the spatial conditions and requirements. Reference symbol 100 motor vehicles 105 Supporting structure 110 wheel 115 bumper system 120 Direction of travel of the motor vehicle 125 cross members 130 first deformation box 135 second deformation box 140 Longitudinal axis of the motor vehicle 200 Center axis of the bumper system 205 Profile 210 strike plate 215 middle longitudinal section 220 stiffening element 225 concave contour 300 first leg 305 second leg 310 connecting bridge 400 notch 405 first flank of the notch 410 second flank of the notch 500 first plunger 505 second plunger 510 first recess 515 Target bending point 520 Target bending point 525 First Section 530 second section 535 second recess 600 piles 605 arrows 700 arrows 900 notch 1000 notch 1005 notch 1010 notch 1200 notch 1300 notch 1400 notch 1405 notch 1500 first guide section 1505 second leadership section 1510 shoe 1600 arrows 1605 Arrow 1700 minting

Claims

[1] Cross member (125) for a bumper system (115) of a motor vehicle (100), which is formed in two parts from a profile (205) which is open on one side in cross section and a closing plate (210) which at least partially closes the profile (205), wherein a stiffening element (220) is arranged on a central longitudinal section (215) and within the cross member (125), which stiffening element is fastened to the profile (205) and is aligned in the direction of the closing plate (210), wherein the stiffening element (220) has a notch (400, 900, 1000, 1005, 1010, 1200, 1300, 1400, 1405) which is designed and arranged on the stiffening element (220) in such a way that in the event of a frontal collision on the central longitudinal section (215) of the cross member (125) flanks (405, 410) of the notch (400, 900, 1000, 1005, 1010, 1200, 1300, 1400, 1405) come into contact with one another at least in sections in order to increase the bending stiffness of the cross member (125),and in the event of a frontal collision with lateral overlap, the stiffening element (220) is locally weakened by the notch (400); , characterized by that the notch (400, 1200, 1300, 1400, 1405) is arranged on a side of the stiffening element (220) facing the striking plate (210); and guide sections (1500, 1505) for guiding the flanks (405, 410) of the notch (400) during a relative movement to one another are arranged on the notch (400, 1400, 1405). [2] Cross member (125) according to claim 1, wherein the stiffening element (220) is a stiffening plate arranged perpendicularly or obliquely to the strike plate (210). [3] Cross member (125) according to claim 2, wherein the stiffening element (220) is integrally connected to the profile (205). [4] Cross member (125) according to claim 3, wherein the stiffening element (220) has a first section (525) coupled to the profile (205), a second section (530) coupled to the profile (205) and a recess (535) arranged between the two sections (525, 530). [5] Cross member (125) according to claim 4, wherein the notch (900, 1000, 1005, 1010) is arranged in the region of the recess (535) on a side of the stiffening element (220) facing the profile (205). [6] Cross member (125) according to one of the preceding claims, wherein the notch (1200, 1300) is formed as an opening in the stiffening element (220). [7] Cross member (125) according to one of the preceding claims, wherein the profile (205) and the stiffening element (220) on the central longitudinal section (215) of the cross member (125) have a contour (225) which is at least partially concave and arranged on a front side of the profile (205) with respect to the forward direction of travel (120) of the motor vehicle (100). [8] Cross member (125) according to one of the preceding claims, wherein the stiffening element (220) has embossments (1800). [9] Cross member (125) according to one of the preceding claims, wherein the profile (205) is designed as a hat profile. [10] Bumper system (115) of a motor vehicle (100), comprising a cross member (125) according to one of the preceding claims, wherein the cross member (125) is arranged transversely to the longitudinal axis (140) of the motor vehicle (100). [11] Bumper system (115) according to claim 10, wherein the striker plate (210) is arranged pointing forward in the longitudinal direction of the motor vehicle. [12] Motor vehicle (100) comprising a bumper system (115) according to one of claims 10 or 11.

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