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) partially closing the profile (205), wherein the profile (205) has a concave contour (405) arranged on a central longitudinal section (400) at a front side (410) of the profile (205) with respect to the forward direction of travel (120) of the motor vehicle (100), and wherein the closing plate (210) extends at a distance from the concave contour (405) on the central longitudinal section (400) of the profile (205). The invention further relates to a bumper system (115) for a motor vehicle (100) and to 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 designed to improve vehicle behavior in different types of collisions or impacts. The behavior of a vehicle and its various structures, assemblies, and components in 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 underlying vehicle support structure 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] US 2020 / 0 332 854 A1 concerns a cross member with a profile open at the bottom and a strike plate located underneath that is firmly connected to the profile. The cross member is designed in such a way that a spaced curvature only occurs in a portion of the cross member in the event of an accident or other impact.

[0007] DE 10 2021 128 850 A1 relates to a cross member according to the preamble of claim 1.

[0008] 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 7, and a motor vehicle according to claim 10. Subclaims represent preferred embodiments.

[0009] According to a first aspect of the invention, a cross member for a bumper system at the front of a motor vehicle is provided, - the cross member is made of two parts - a profile with a cross-section that is open on one side and in the forward direction of travel, and - a locking plate which partially closes the profile and is arranged in front of the profile in the forward direction of travel.

[0010] According to the invention, - that the profile has, at least in sections, a concave contour on a central longitudinal section, which is arranged on a front side of the profile facing the forward direction of travel of the motor vehicle and is concave when viewed from above, and - that the locking plate has a curvature in the area of ​​the central longitudinal section of the profile, which is spaced apart from the concave contour in the forward direction of travel, - complementary to the concave contour and curved forwards in the direction of travel and - which is arranged and designed to come into contact with the concave contour of the profile when a force acting on the central longitudinal section is directed counter to the forward direction of travel of the motor vehicle.

[0011] In other words, the concave contour on the central longitudinal section of the cross member or profile is a partially circular depression in the X-direction of the bumper system or the motor vehicle. The concave contour is designed to accommodate an obstacle in the form of a pole in the event of a frontal collision in the "pole-center" load case. The concave shape forms a predetermined bending point of the profile, thus achieving targeted deformation behavior of the cross member in the "pole-center" load case. Consequently, an NCAP result for the "pole-center" load case is improved, and the motor 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 proposed here does not negatively influence the deformation behavior in the MPDB load case.

[0012] When a force acts on the crossbeam in the "pile-center" load case, the pile presses the locking plate into the convex contour of the profile with initially lower required force, so that the locking plate at least partially contacts the profile before the profile begins to deform as the force continues to apply. This ensures that a load path is not interrupted or remains uninterrupted during the force application.

[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, with the exception of the central longitudinal section. 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 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.

[0016] 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.

[0017] The striking plate is preferably designed and arranged to come into contact with the concave contour of the profile when a force is applied to the central longitudinal section in a direction opposite to the forward direction of travel of the motor vehicle. In other words, the striking plate is arranged facing forward when the cross member or bumper system coupled to the front of the motor vehicle is in the assembled state, wherein in the "pole-center" load case, the striking plate is pressed by the pole, in particular over its entire surface, against the curved central longitudinal section of the profile and in doing so conforms to the concave structure of the profile without tearing. The striking plate therefore has enough material in the region of the central longitudinal section and optionally such deformation and, where appropriate, flow behavior that failure, in particular tearing, of the sheet is prevented.

[0018] In this sense, the shape and structure of the strike plate at the center longitudinal section of the profile ensures that there is just enough material available for the strike plate to fit into the recess of the profile at its center longitudinal section in the "pile-center" load case without tearing. By preventing failure of the strike plate, it can be ensured that the load path does not break in the event of a collision.

[0019] According to one embodiment, the strike plate has a curvature in the central longitudinal section of the profile. In particular, the strike plate is at least partially concave in the region of the central longitudinal section of the profile. The curvature protrudes beyond the shape of the remaining strike plate in the forward direction of travel of the motor vehicle or in the X-direction. With regard to the shape of the remaining strike plate, which can also be at least partially concave in plan view, the shape of the strike plate in the central longitudinal section of the profile is to be understood as a projection or bulge directed forward in the forward direction of travel of the motor vehicle.

[0020] Preferably, the curvature of the strike plate and the concave contour of the profile have an identical radius, at least in sections. This ensures that the strike plate has just enough material at the central longitudinal section of the profile to bridge the path in the X direction to the contour of the profile when force is applied, or to elastically deform and fully engage the profile without undergoing such plastic deformation that the strike plate fails or cracks. The curvature is preferably mirror-symmetrical.

[0021] In principle, the striking plate can be shaped in any way at the middle longitudinal section of the profile, although there must always be enough material available to allow the striking plate to deform and come into contact with the profile without the striking plate tearing and thus interrupting the load path. For example, the striking plate can have a wave-like shape in the plan view of the cross member. Alternatively or additionally, the striking plate can have edges or corners in the plan view. In any case, the structure of the striking plate or the additional material at the middle longitudinal section of the profile ensures that in the "pile center" load case, the striking plate can bridge the distance between the striking plate in its initial state and the concave contour of the profile without tearing.

[0022] 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.

[0023] The bumper system is designed to absorb forces from a frontal collision. The bumper system can also be understood as the crash management system of the motor vehicle and is connected directly or indirectly, in particular via the deformation boxes, to the supporting structure of the motor vehicle. The bumper system is designed to absorb forces from a collision. The cross member is arranged essentially perpendicular to the direction of travel of the motor vehicle or extends in the vehicle's transverse direction over a large part of the vehicle's width. The cross member absorbs energy in the event of an impact and distributes the resulting forces. The cross member is very strong, has good energy absorption capacity, and is very deformable, so that it can deform and absorb energy in the event of a collision without failing.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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; Fig. 2 a schematic plan view of the bumper system according to the invention according to Fig. 1 with a cross member according to the invention; Fig. 3 a highly schematic cross-sectional view of the bumper system according to the invention according to Fig. 1 and Fig. 2; Fig. 4 a first schematic plan view of a central longitudinal section of the cross member according to the invention according to Fig. 2 and Fig. 3 in the initial state; and Fig. 5 a second schematic plan view of the central longitudinal section according to Fig. 4 after a frontal collision in the “pile-center” load case.

[0029] After Fig. 1 shows a motor vehicle 100 having a supporting 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 supporting 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 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 supporting 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.

[0030] The bumper system 115 according to the invention comprises Fig. 1 to Fig. 3 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 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). The direction of travel 120 is aligned along the longitudinal direction of the motor vehicle and along the longitudinal axis 140.

[0031] After Fig. 2, the cross member 125 is curved. The cross member 125 is formed in two parts, consisting of 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.

[0032] The strike plate 210 is arranged facing forward in the direction of travel 120, or the forward direction of travel of the motor vehicle 100. In the present case, the strike plate 210 is made of metal, in particular steel, while the profile 205 is made of a fiber-reinforced plastic.

[0033] According to the Fig. 4 and Fig. 5, the cross member 125, in particular its central longitudinal section 400, is shown in different states. Fig. 4 shows the cross member 125 in its initial state. Fig. 5 shows the cross member 125 after a frontal collision in the “pile-center” load case.

[0034] The profile 205 has a concave contour 405 on the central longitudinal section 400. The concave contour 405 is to be understood as a recess or depression in the profile 205 opposite to the direction of travel 120 of the motor vehicle 100. The concave contour 405 is formed on a front side 410 of the profile 205 with respect to the direction of travel 120 of the motor vehicle 100. The contour 405 is designed as a negative profile of a test pile for the "pile center" load case.

[0035] The striking plate 210 has a curvature 415 on the central longitudinal section 400 of the profile 205, which is complementary to the contour 405 and is curved forward in the direction of travel 120 or in the X direction. The striking plate 210 extends along the central longitudinal section 400 of the profile 205 at a distance from the concave contour 405, wherein the shape of the contour 405 and the striking plate 210 in the region of the central longitudinal section 400 in plan view forms a lens-shaped gap between the profile 205 and the striking plate 210. The curvature 415 of the striking plate 210 and the concave contour 405 of the profile 205 have a substantially identical radius. The developed length of the inner side of the curvature 415 essentially corresponds to the developed length of the concave contour 405. The radius can be adapted to the specifications of the “pile center” load case, in particular the diameter of the pile in the test (not shown here).The lowest point of the concave contour 405 lies on the longitudinal axis 140 of the motor vehicle 100 or on the center axis 200 of the bumper system 115. Thus, the concave contour 405 is mirror-symmetrical. The curvature 415 is correspondingly mirror-symmetrical. The central longitudinal section 400 of the profile 205 lies in the area Y0 of the cross member 125.

[0036] The locking plate 210 is arranged and designed to move in the direction of arrow 500 when a force is applied that is directed against a forward direction of travel or the direction of travel 120 of the motor vehicle 100. Fig.5 to the central longitudinal section 400 to rest on the concave contour 405 of the profile 205. The curvature 415 is designed and shaped such that there is enough material for the locking plate 210 to lie in the recess or to rest on the contour 405 curved in a partial circle shape without cracking or failing. This ensures a continuous, uninterrupted load path in the "pile center" load case. 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 300 first leg 305 second leg 310 connecting bridge 400 middle longitudinal section 405 Contour of the profile 410 front 415 Curvature 500 arrows

Claims

[1] Cross member (125) for a bumper system (115) on the front of a motor vehicle (100), - wherein the cross member (125) consists of two parts - a profile (205) which is open on one side in cross-section and which is open in the forward direction of travel (120), and - a locking plate (210) partially closing the profile (205) which is arranged in front of the profile (205) in the forward direction of travel (120), characterized by , - that the profile (205) has, at least in sections, a concave contour (405) on a central longitudinal section (400), which is arranged on a front side (410) of the profile (205) facing the forward direction of travel (120) of the motor vehicle (100) and is concave when viewed from above, and - that the locking plate (210) has, in the region of the central longitudinal section (400) of the profile (205), a curvature (415) extending in the forward direction (120) at a distance from the concave contour (405), which - complementary to the concave contour (405) and curved forwards in the direction of travel and - which is arranged and designed to come into contact with the concave contour (405) of the profile (205) when a force is applied to the central longitudinal section (400) in a direction opposite to the forward direction of travel of the motor vehicle (100). [2] Cross member (125) according to claim 1, wherein in the region of the central longitudinal section (400) a lens-shaped gap is formed between the profile (205) and the striking plate (210) as viewed from above by the shape of the concave contour (405) and the striking plate (210). [3] Cross member (125) according to claim 1 or 2, wherein the curvature (415) of the locking plate (210) and the concave contour (405) of the profile (205) have an identical radius at least in sections. [4] Cross member (125) according to one of the preceding claims, wherein a development length of the inner side of the curvature (415) corresponds to a development length of the concave contour (405). [5] Cross member (125) according to one of the preceding claims, wherein the profile (205) is designed as a hat profile. [6] Cross member (125) according to one of the preceding claims, wherein the lowest point of the concave contour (405) lies on a central axis (200) of the bumper system (115). [7] 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). [8] Bumper system (115) according to claim 7, wherein the cross member (125) is arranged on two deformation boxes (130, 135) aligned parallel to the longitudinal axis (140) of the motor vehicle (100). [9] Bumper system (115) according to claim 7 or claim 8, wherein the striker plate (210) is arranged pointing forward in the longitudinal direction of the motor vehicle. [10] Motor vehicle (100), comprising - a cross member (125) according to one of claims 1 to 6 and / or - a bumper system (115) according to one of claims 7 to 9.

Images