Cross member for a bumper system of a motor vehicle, bumper system comprising such a cross member, and motor vehicle comprising such a bumper system

Abstract

The invention relates to a cross member (125) for a bumper system (115) of a motor vehicle (100), which cross member is designed in two parts from a profile (205) which is open on one side in cross-section and a closure plate (210) which at least partially closes the profile (205), wherein a first shaped element (405) is arranged on a central longitudinal portion (400) of the closure plate (210), wherein a second and third shaped element (410, 415) are arranged on both sides of a central axis (200) of the cross member (125) at a distance from said central axis (200), wherein the second shaped element (410) and the third shaped element (415) are positioned relative to the first shaped element (405) such that, in the event of a head-on collision at the central longitudinal portion (400) of the closure plate (210), which central longitudinal portion lies on the central axis (200), they engage interlockingly with one another, and, in the event of a head-on collision with lateral overlap, they remain free of contact points with the first shaped element (405). The invention also relates to a bumper system (115) for a motor vehicle (100) and to a motor vehicle (100).

Description

[0001] Cross member for a bumper system of a motor vehicle, bumper system with such a cross member and motor vehicle with such a bumper system

[0002] 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.

[0003] 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, which is 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.

[0004] 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 an assessment of 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.

[0005] 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.

[0006] 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.

[0007] 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 conflicting objective. 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 9, and a motor vehicle according to claim 11. 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 striker plate which at least partially closes the profile, wherein a first shaped element is arranged on a central longitudinal section of the striker plate, wherein a second and third shaped element are arranged on both sides of a central axis of the cross member at a distance from the central axis, wherein the second shaped element and the third shaped element are arranged relative to the first shaped element such that in the event of a frontal collision they engage in a form-fitting manner at the central longitudinal section of the striker plate lying on the central axis and remain free of contact points with the first shaped element in the event of a frontal collision with lateral overlap.

[0009] In other words, the form elements for the “pile center” load case are used to create a stiffening mechanism in which the form elements only form a positive connection with one another when an object, in particular the pile according to the “pile center” load case, collides with the cross member at the central longitudinal section. In this case, the first form element forms a positive connection with both the second form element, which is assigned to the left side of the vehicle or the first deformation box, and the third form element, which is assigned to the right side of the vehicle or the second deformation box, so that a wedging or interlocking is created which makes it more difficult for the cross member to bend in the “pile center” load case compared to an initial or undamaged state. Accordingly, the form elements engage or interlock with one another to form the positive connection.They interlock when the pile intrudes into the crossbeam at the middle longitudinal section, which is located in the YO area of ​​the crossbeam, in the "pile-center" load case. The stiffening mechanism is therefore only triggered in the "pile-center" load case. This mechanism increases the area moment of inertia or section modulus, making deflection of the crossbeam more difficult. In other words, when a force acts on the middle longitudinal section in the "pile-center" load case, the flexural stiffness increases.

[0010] The shaped elements are to be understood as stiffening elements which, when they interlock, in particular when they are pushed onto one another or into one another, create a positive connection to increase the rigidity, in particular the flexural rigidity, of the cross member.

[0011] At the same time, the shaped elements are designed and arranged relative to each other in such a way that the first shaped element, particularly in the MPDB load case or in a frontal collision with lateral overlap, neither engages nor forms a positive connection with the second shaped element or the third shaped element. "Free of contact points" in this context means that the shaped elements do not touch each other in or during the MPDB load case and thus cannot form a positive connection for local stiffening of the cross member.

[0012] 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.

[0013] 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.

[0014] 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.

[0015] The profile has a concave contour at the central longitudinal section, located at the front of the profile relative to the forward direction of travel of the motor vehicle, which is at least partially concave. The concave contour at the central longitudinal section of the cross member or profile is a partially circular recess 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.

[0016] The concave shape located at the front of the vehicle's central longitudinal section, in the forward direction of travel, creates a predetermined kink in 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.

[0017] Optionally, the locking plate also features a predetermined bending point in the middle longitudinal section of the crossbeam. This allows the deformation behavior of the crossbeam to be further improved and better controlled in the "pile center" load case.

[0018] The respective target bending point is preferably located on the center axis. This ensures that in a frontal collision with lateral overlap, the deformation behavior of the cross member is essentially identical, regardless of the vehicle side.

[0019] The deepest point of the concave contour preferably lies on a center axis of the bumper system. In other words, the furthest rearward point of the profile's recess in the forward direction of travel lies on the center or symmetry axis of the cross member or bumper system. The central longitudinal section therefore lies on the longitudinal axis of the vehicle or the center axis of the cross member and is shaped with mirror symmetry.

[0020] 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 360 mm. Accordingly, the concave contour of the profile has a radius of 360 mm, at least in 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.

[0021] The molded elements are preferably arranged inside the cross member. In other words, the molded elements are integrated into the cross member. This allows the stiffening mechanism to be implemented without affecting the overall installation space.

[0022] Preferably, the first shaped element has recesses for accommodating complementary sections of the second and third shaped elements. This allows for an easily manufactured toothing geometry with the shaped elements engaging with each other in the "pile center" load case. Depending on the design, the toothing geometry can also be a ribbed structure.

[0023] The shaped elements can be an integral part of the cross member, i.e., the profile or the striking plate. Alternatively, the shaped elements can be separate components that are attached to the profile or the striking plate. In this sense, one embodiment of the invention provides that the first shaped element is integrally connected to the striking plate and / or that the second and third shaped elements are integrally connected to the profile. A material-to-material connection describes a non-detachable connection between two or more materials in which the molecules of the materials are bonded to one another. Stability is created by chemical or physical forces, such as bonds or adhesion. An advantageous material-to-material connection between the two components is a welded connection. An adhesive connection is also conceivable.If both the profile and the strike plate are made of metal, a welded connection is advantageous. Of course, it is conceivable that the shaped elements and the strike plate or profile are designed in such a way that they can be screwed together.

[0024] In one embodiment, the locking plate rests against the second and third shaped elements. In other words, the second and third shaped elements are arranged in the interior of the cross member and in the vehicle's longitudinal direction between the profile, in particular the connecting web, and the locking plate. The second and third shaped elements are each attached to the profile and already rest against the locking plate in the initial state of the cross member. This allows the flexural rigidity of the cross member to be further increased for the "pile-center" load case, and an interruption of the load path is prevented.

[0025] 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.

[0026] 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 which is open on one side in cross section and a closing plate which at least partially closes the profile, wherein a first shaped element is arranged on a central longitudinal section of the closing plate, wherein a second and third shaped element are arranged on both sides of a central axis of the cross member lying on the longitudinal axis between the central axis and the deformation boxes, wherein the second shaped element and the third shaped element are arranged relative to the first shaped element and spaced from the central axis,that in the event of a frontal collision they engage positively at the central longitudinal section of the strike plate lying on the central axis and remain free of contact points with the first shaped element in the event of a frontal collision with lateral overlap.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] The invention will now be described in more detail with reference to the accompanying drawings, in which:

[0033] Figure 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;

[0034] Figure 2 shows a first schematic plan view of the bumper system according to the invention according to Figure 1 with a cross member according to the invention in an initial state;

[0035] Figure 3 is a highly schematic cross-sectional view of the bumper system according to the invention shown in Figures 1 and 2;

[0036] Figure 4 shows a second schematic plan view of the bumper system according to the invention according to Figures 1 to 3 in the initial state - shown only partially here;

[0037] Figure 5 is a third schematic plan view of the bumper system according to the invention according to Figures 1 to 4 - shown only partially here - during a frontal collision in the “pole-center” load case;

[0038] Figure 6 is a fourth schematic plan view of the bumper system according to the invention, shown only partially here, according to Figures 1 to 5 during a frontal collision with lateral overlap; and

[0039] Figure 7 is a schematic plan view of the bumper system according to the invention—shown only partially here—according to a second embodiment in an initial state; wherein identical or similar components are provided with the same reference numerals.

[0040] Figure 1 shows a motor vehicle 100 having 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. A bumper system 115 according to the invention is connected to the support structure 105 at the front of the motor vehicle 100. A bumper system can also be arranged at the rear of the motor vehicle 100, although this will not be described in 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.

[0041] According to Figures 1 to 3, the bumper system 115 according to the invention comprises 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).

[0042] According to Figure 2 in combination with Figure 3, the cross member 125 is formed in two parts, consisting of a profile 205 open on one side in cross-section and a locking plate 210 partially closing the profile 205. According to Figure 3, the profile 205 has two legs 300, 305, which are connected to one another in one piece 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.

[0043] Figures 4 to 7 illustrate that a first shaped element 405 is arranged on a central longitudinal section 400 of the locking plate 210 on its profile 205 or on the inward-facing side. The first shaped element 405 lies on the central axis 200 of the cross member 125. Shaped elements 410, 415 are arranged on both sides of the central axis 200. The second shaped element 410 is arranged on the left between the central axis 200 and the first deformation box 130, and the third shaped element 415 is arranged on the right between the central axis 200 and the second deformation box 135. The shaped elements 405, 410, 415 form the aforementioned stiffening mechanism for the "pile center" load case. The shaped elements 405, 410, 415 are arranged in the interior 420 of the cross member 125. The profile 205 and the locking plate 210 spatially delimit the interior space 420 of the cross member 125, in which the stiffening mechanism for the “pile center” load case is arranged.The first shaped element 405 is welded to the strike plate 210. The second and third shaped elements 410, 415 are welded to the profile 205.

[0044] 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 425 on a front side of the central longitudinal section 400 relative to the direction of travel 120. In the initial state according to Figures 2 to

[0045] 4, the locking plate 210 runs in the area of ​​the concave contour 425 at a distance from the profile 205. The concave contour 425 forms a predetermined bending point for the locking plate 210, which ensures that the cross member 125 in the “pile-center” load case, i.e. in the case of a central frontal collision with the pile shown in Figure

[0046] 5, the desired deformation behavior for this load case is realized.

[0047] Figure 5 shows the state at the beginning of the "pile center" load case. When the pile 500 impacts the central longitudinal section 400 of the locking plate 210, which lies on the central axis 200, a force acts on the cross member 125 in the direction of arrow 505. Figure 5 clearly shows that the concave contour 425 is designed as a negative form for the pile 500. In the "pile center" load case, a path with lower resistance is initially bridged before the locking plate 210 contacts the concave contour 425 of the profile 205 and the forces are transferred into the profile 205. This ensures that the load path remains uninterrupted and does not break off.

[0048] According to Figure 4, the first shaped element 405 has recesses 430 for receiving complementary sections 435, 440 of the second and third shaped elements 410, 415. As a result of the force, the cross member 125 is deformed such that the section 435 of the second

[0049] The first shaped element 410 and the section 440 of the third shaped element 415 each engage the corresponding recess 430 of the first shaped element 405, as can be seen in Figure 5. Thus, the shaped elements 405, 410, 415 engage with each other in a form-fitting manner, thus increasing the area moment of inertia of the cross member 125 for the "pile center" load case. This locally increases the flexural rigidity of the cross member 125 compared to other load cases, particularly the MPDB load case.

[0050] The MPDB load case is illustrated in Figure 6, according to which, in a frontal collision with lateral overlap, here on the left side of the vehicle, the cross member 125 deforms due to the force applied in the direction of arrow 600. The shaped elements 405, 410, 415 are shaped and arranged relative to one another in such a way that they do not engage with one another or form a positive connection in the MPDB load case. In this sense, the area moment of inertia of the cross member 125 is also not increased. Consequently, the cross member 125 has a lower flexural rigidity in the MPDB load case than in the "pile center" load case.

[0051] Figure 7 shows an alternative embodiment of the bumper system 115 in an initial state. Accordingly, the striker plate 210 rests with its inward-facing side against the second and third shaped elements 410, 415 without being integrally connected thereto. Due to the shape of the second and third shaped elements 410, 415 proposed here, the load path can be better maintained during the "pole-center" load case, since energy is transferred from the second and third shaped elements 410, 415 to the profile 205 right at the beginning of the force acting on the cross member 125. In this case, the flexural rigidity is already greater than in other load cases, even before the second and third shaped elements 410, 415 engage with the first shaped element 405 in the "pole-center" load case. The positive connection is only created, or the stiffening mechanism is only activated, when the

[0052] The striking plate 210 has been deformed in the X-direction or opposite to the direction of travel 120 by the path defined by the design of the concave shape 425, until the first shaped element 405 comes into engagement with the second and third shaped elements 410, 415.

[0053] The deformation behavior of the bumper system 115 shown in Figure 7 is otherwise identical to Figures 5 and 6 for the MPDB and "pile center" load cases, which is why a corresponding illustration is omitted. Reference is made accordingly to the explanations for the first embodiment shown in Figures 1 to 6.

[0054] Of course, it is conceivable to reverse the design of the form elements. Accordingly, the first form element 405 can have shaped sections analogous to the sections 435, 440, while the second and third form elements 410, 415 can have corresponding recesses analogous to the recesses 430. Regardless of the shape and design of the form elements, in the "pile center" load case, a stiffening of the cross member 125 or a wedging of the profile 205 relative to the

[0055] A locking plate 210 is implemented to impede the deflection of the cross member 125. Other design variants of the shaped elements 405, 410, 415 are also conceivable, allowing a positive fit or an increase in the flexural rigidity of the cross member 125 in the "pile center" load case.

[0056] Reference symbol

[0057] Motor vehicle

[0058] Support structure

[0059] wheel

[0060] bumper system

[0061] Direction of travel of the motor vehicle

[0062] Cross member first deformation box second deformation box

[0063] Longitudinal axis of the motor vehicle

[0064] Center axis of the bumper system

[0065] profile

[0066] Strike plate first leg second leg

[0067] connecting bridge

[0068] Middle longitudinal section of the cross member first shaped element second shaped element third shaped element

[0069] Interior of the cross member

[0070] Contour of the profile

[0071] Recess on the first form element

[0072] Section of the second form element

[0073] Section of the third form element

[0074] post

[0075] Arrow

[0076] Arrow

Claims

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 striker plate (210) which at least partially closes the profile (205), wherein a first shaped element (405) is arranged on a central longitudinal section (400) of the striker plate (210), wherein a second and third shaped element (410, 415) are arranged on both sides of a central axis (200) of the cross member (125) at a distance from the central axis (200), wherein the second shaped element (410) and the third shaped element (415) are arranged relative to the first shaped element (405) in such a way that in the event of a frontal collision they engage in a form-fitting manner on the central longitudinal section (400) of the striker plate (210) lying on the central axis (200) and in the event of a frontal collision with lateral Overlap remain free of contact points with the first form element (405).

2. Cross member (125) according to claim 1, wherein the profile (205) at the central longitudinal section (400) has a contour (425) 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).

3. Cross member (125) according to claim 1 or claim 2, wherein the shaped elements (405, 410, 415) are arranged in the interior space (420) of the cross member (125).

4. Cross member (125) according to claim 3, wherein the first shaped element (405) has recesses (430) for receiving sections (435, 440) of the second and third shaped elements (410, 415) which are formed complementarily thereto.

5. Cross member (125) according to one of the preceding claims, wherein the first shaped element (405) is integrally connected to the striking plate (210).

6. Cross member (125) according to one of the preceding claims, wherein the second and third shaped elements (410, 415) are integrally connected to the profile (205).

7. Cross member (125) according to claim 6, wherein the locking plate (210) bears against the second and third shaped elements (410, 415).

8. Cross member (125) according to one of the preceding claims, wherein the profile (205) is designed as a hat profile.

9. 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).

10. Bumper system (115) according to claim 9, wherein the striker plate (210) is arranged pointing forward in the longitudinal direction of the motor vehicle.

11. Motor vehicle (100) comprising a bumper system (115) according to one of claims 9 or 10.

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