Bumper system for a motor vehicle and motor vehicle with such a bumper system

Abstract

The invention relates to a bumper system (115) for a motor vehicle (100), comprising a cross member (125) arranged substantially transversely to the forward direction of travel (120) of the motor vehicle (100), which cross member is fastened asymmetrically and eccentrically to two shock absorbers (130) arranged substantially longitudinally to the forward direction of travel of the motor vehicle (100), wherein the cross member (125) has a striker plate (200) and a profile (300) arranged behind the striker plate (200) in the forward direction of travel (120) of the motor vehicle (100), characterized in that in the region of the shock absorbers (130) on the striker plate (200) a tab (205) is arranged, which, with respect to the forward direction of travel (120) of the motor vehicle (100), is bent backwards at an obtuse angle relative to the remaining striker plate (200) and is fastened to the associated shock absorber (130). The invention further relates to a motor vehicle (100) having such a bumper system (115).

Description

[0001] The invention relates to a bumper system for a motor vehicle, comprising a cross member arranged substantially transversely to the direction of travel of the motor vehicle, which is fastened asymmetrically and eccentrically to two shock absorbers arranged substantially longitudinally to the forward direction of travel of the motor vehicle. The cross member is formed in two parts, consisting of a profile that is open on one side in cross-section and a closing plate that at least partially closes the profile. Furthermore, the invention relates to a motor vehicle with at least one such bumper system.

[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 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 underlying vehicle support structure, in particular the engine mount, remains as undamaged as possible. For this purpose, bumper systems today include a so-called crash management system (CMS) with cross members, longitudinal members, and deformation boxes or shock absorbers.The shock absorbers, also called crash boxes, can be attached to the respective longitudinal members at one end, i.e., at one axial end, and are connected to the cross member at the other end, i.e., at the opposite end. The energy resulting from an impact is dissipated from the cross member via the shock absorbers into the longitudinal members.

[0003] As part of full-vehicle testing, an analysis of a mobile offset progressive deformable barrier (MPDB) at high speed is carried out. The MPDB barrier typically has a honeycomb structure with several, often three, strength zones.

[0004] In the MPDB barrier analysis, a test vehicle is driven into a mobile, progressive, deformable obstacle, also called a barrier, mounted on an oncoming 1400 kg car. The test simulates a frontal impact between the test vehicle and a typical mid-size family car. Among other things, the risk of head, neck, chest, and abdominal injuries to vehicle occupants can be assessed by analyzing the barrier's post-impact footprint. To structurally address this load case, vehicles are equipped with load distribution frames or other load-dissipating or load-distributing structures in addition to the CMS, which can absorb and dissipate impact energy, particularly in frontal collisions with a small overlap.Frontal collisions with small overlap primarily impact the vehicle's outboard wheels, which may not be directly protected by any of the primary crumple zone structures, particularly the CMS. A load distribution frame is typically located rearward of the cross member in the direction of travel and has sections that project laterally beyond the cross member with respect to the vehicle width, thus extending in the forward direction of travel in front of a wheel housing of the respective wheel in the vehicle transverse direction.

[0005] In the MPDB frontal crash load case, achieving the most homogeneous barrier footprint possible is crucial for the vehicle's classification. Due to the sweep angle of the vehicles and the resulting space constraints, it is desirable to achieve a uniform force-displacement curve across the entire vehicle width.

[0006] For cross members that are asymmetrically and off-center connected to impact absorbers, also known as crash boxes, the off-center integration and force introduction lead to a torque introduction around the vehicle's transverse axis. This can cause an upper edge of the cross member and impact absorber to rotate forward like a rigid edge due to the rotation. This can lead to a higher standard deviation in the MPDB barrier or even a bottoming-out risk.

[0007] JP 2012 - 6 513 A and DE 10 2021 102 366 A1 show bumper systems with symmetrical connection of a cross member to two bumpers.

[0008] US 5,100,189 A shows a bumper system with asymmetric connection of a cross member to two bumpers.

[0009] DE 10 2009 005 606 A1 shows a bumper system with a lower tapered bumper behind a cross member.

[0010] DE 10 2023 131 028 B3 shows a bumper system according to the preamble of claim 1.

[0011] Based on the prior art, the object of the invention is to provide a bumper system with a cross member arranged asymmetrically and eccentrically on shock absorbers, as well as a motor vehicle with such a bumper system, which improves the rigidity of a vehicle front in the transverse direction, in particular making it more uniform across the entire vehicle width. Furthermore, the bumper system should be more flexibly adaptable to design requirements and / or requirements regarding a cooling air mass flow. The respective object is achieved by a bumper system for a motor vehicle according to claim 1 and by a motor vehicle according to claim 10. Subclaims represent preferred embodiments.

[0012] A bumper system according to the invention for a motor vehicle comprises - a cross member arranged essentially transversely to the forward direction of travel of the motor vehicle, - which is attached to two shock absorbers arranged essentially longitudinally to the forward direction of travel of the motor vehicle in such an asymmetrical and off-center manner that, when viewed in cross-section through the cross member in the area of ​​the respective shock absorber - an axis of symmetry of the cross member - from a central axis of the respective shock absorber - has a vertical distance greater than 5 percent of the height over which the respective shock absorber extends, - where the cross member - a strike plate and - has a profile arranged behind the locking plate in the forward direction of travel of the motor vehicle, - where in the area of ​​the shock absorbers on the strike plate there is a tab which - bent backwards at an obtuse angle relative to the rest of the locking plate in relation to the forward direction of travel of the motor vehicle and - is connected to the corresponding shock absorber.

[0013] According to the invention, - that the profile of the cross member has a height extension that lies entirely within the height over which the respective shock absorber extends, and - that the respective shock absorber reaches up to the strike plate at its vertical end of this height opposite the tab.

[0014] In other words, the striker plate comprises a first section which is essentially vertical in cross-section and extends in the longitudinal direction of the cross member, i.e. essentially in the transverse direction of the vehicle, and is connected to both the profile and the shock absorbers, or vice versa. At the connection points of the shock absorbers to the cross member, in particular the striker plate, a second section is arranged on the striker plate, which is angled or bent backwards in the forward direction of travel. The second section can be integrally connected to the first section via a kink point which extends essentially horizontally when the bumper system is assembled.

[0015] The cross member is part of the crash management system and is connected to a supporting structure of the motor vehicle, in particular an engine mount, via the bumpers. The cross member is arranged essentially transversely to the forward or rearward direction of travel of the motor vehicle and thus extends across a large part of the vehicle's width in the transverse direction. The cross member absorbs energy in the event of an impact and transfers the resulting forces to the bumpers.

[0016] The tabs or second sections ensure complete connection of the cross member to the shock absorbers despite the asymmetrical and off-center arrangement of the cross member, in particular of the profile, to the shock absorbers. At the bending point, the respective second section or tab is bent backward at an obtuse angle relative to the first section in relation to the forward direction of travel of the vehicle. An obtuse angle is between 90° and 180°. This includes all angles that lie between a right angle and a straight angle. The tabs are arranged on an upper side of the striker plate, so that the tabs extend diagonally backward and upward, starting from the essentially vertical striker plate.

[0017] The strike plate closes the cross member at the front in the forward direction of travel. The tabs are sections of the strike plate that protrude upwards in the direction of gravity and, particularly in one-piece designs, are angled by forming. The strike plate is arranged with the tabs on the front of the cross member. The shock absorber is chamfered to match the obtuse angle so that the respective tab can rest on the corresponding shock absorber and be connected to the shock absorber. The selected angle depends on the eccentricity of the connection of the cross member to the shock absorbers. The tabs can be connected to the strike plate. The tabs are preferably connected to the strike plate as a single piece.

[0018] According to one embodiment, the cross member is formed in two parts from a profile that is open on one side in cross section and in the forward direction of travel of the motor vehicle and a locking plate that at least partially closes the profile.

[0019] Alternatively, a one-piece implementation of the cross member is possible using an extruded aluminum profile, in which the contour of the cross member is extruded as a single piece. Alternatively, the cross member can be designed as an aluminum or steel roll-formed profile. For both alternatives, excess material can be subsequently punched out to the sides of the tabs, particularly between the tabs, in order to realize the aforementioned advantages of this bumper system design. If the cross member is designed as a single piece, the tabs are connected to the profile and the striker plate as a single piece.

[0020] In contrast to previously known cross members, which are usually connected symmetrically and centrally to the shock absorbers, the area of ​​the striker plate between the tabs is recessed so that the bumper system can be adapted to special design requirements and / or to meet requirements regarding the guidance of a cooling air mass flow.

[0021] An "asymmetric and off-center" arrangement of the cross member on the shock absorbers exists if, when viewed in cross-section through the cross member and in the area of ​​the shock absorber, the axis of symmetry of the cross member, in particular the profile of the cross member, deviates from the axis of symmetry of the respective shock absorber by more than 5% of the height of the crash box. Preferably, the cross member, in particular the profile, is connected to the shock absorbers vertically offset downwards, with the axis of symmetry of the profile being connected at a distance from the center axis of the respective shock absorber that is greater than 5% of the height of the respective shock absorber.

[0022] In the event of a crash, i.e., during an impact of the MPDB barrier, the off-center integration and force introduction of the cross member to the impact absorbers leads to a torque introduction around the vehicle's transverse axis, which rotates or deforms the cross member about the vehicle's transverse axis. This impact is to be understood as an MBDP load case, especially when analyzing the MPDB barrier. The beveled impact absorber and the strike plate in front of it with the corresponding tab increase the effective area of ​​the cross member and thus the effective area into the MPDB barrier, which in turn allows the respective impact absorber to fold through more easily. This leads to a lower standard deviation in the MPDB barrier and minimizes the risk of bottoming out. Thus, the result of the MBDP load case analysis is improved.

[0023] The cross member preferably has a longitudinal section arranged between the two shock absorbers as well as sections projecting beyond the shock absorbers, wherein the respective tab is arranged in the transition region between the longitudinal section and the corresponding projecting section. In particular, the tabs are arranged on an upper side of the striking plate in the assembled state. Accordingly, the section of the cross member that extends between the connection points of the shock absorbers is defined as the longitudinal section, and the arms or sections that extend beyond or protrude beyond the connection points are each to be understood as a projecting section within the meaning of the invention. The longitudinal section and the projecting sections are preferably formed in one piece and merge into one another. The cross member and thus also the longitudinal section and the projecting sections can be curved at least in sections.

[0024] At the connection points, the cross member can also bend backwards, opposite to the forward direction of travel.

[0025] The projecting sections are preferably designed and arranged mirror-inverted around the vehicle's longitudinal axis. In particular, the cross member, in particular the profile and the striker plate, as well as the shock absorbers, are designed mirror-symmetrically. The projecting sections are to be understood as cantilever sections of the cross member that protrude beyond the respective shock absorber toward the side of the vehicle, in particular at an angle to the vehicle's longitudinal and transverse directions.

[0026] The profile is preferably a hat profile. The hat profile distributes the impact energy and partially absorbs it. The shape of the hat profile, i.e., an inverted hat, ensures high bending and torsional rigidity. This is particularly important because the cross member is exposed to strong forces and deformations. The hat profile has a U-shaped base and can be connected to the strike plate directly or via lateral flanges. In the event of a crash, the hat profile is connected to the shock absorbers to distribute the force. The respective shock absorber is preferably made of metal. Alternatively, the profile can also be designed as a C-profile.

[0027] According to one embodiment, the striker plate and the tabs are integrally connected to the associated shock absorber. The respective shock absorber, which is hollow inside, has corresponding contact sections and / or surfaces that complement the shape of the striker plate and the profile in the connection area of ​​the shock absorbers.

[0028] Preferably, the strike plate and the profile are integrally bonded, at least in sections. The strike plate can be glued and / or welded to the profile, or vice versa.

[0029] The bumper system according to the invention can advantageously be used in a motor vehicle according to the invention. The motor vehicle comprises a supporting structure and, in front of and behind it in the direction of travel, a bumper system or an impact-damping device. One or both bumper systems, preferably at least the front bumper system in the forward direction of travel, is designed as a bumper system according to the first aspect of the invention. Preferably, both bumper systems are designed as bumper systems according to the first aspect of the invention.

[0030] The invention will now be described in more detail with reference to the accompanying drawings, in which: Fig. 1 a highly simplified plan view of a motor vehicle according to the invention with a bumper system according to the invention; Fig. 2 a schematic perspective view of the bumper system according to the invention according to Fig. 1; Fig. 3 a schematic longitudinal section through a shock absorber of the bumper system according to the invention according to Fig. 1 and Fig. 2 in an initial state; and Fig. 4 a schematic side view of the shock absorber of the bumper system according to the invention according to Fig. 3 during an impact, in particular against an MPDB barrier; illustrated, wherein identical or similar components are provided with the same reference numeral.

[0031] After Fig. 1 shows a motor vehicle 100 having a support structure 105, represented here in a highly simplified manner by a dashed rectangle, 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, but this will not be described in detail here.

[0032] In any case, it is conceivable that the bumper system on the rear of the motor vehicle 100 is designed analogously to the bumper system 105 according to the invention described below and is connected to the support structure 115.

[0033] The bumper system 115 according to the invention comprises Fig. 1 in conjunction with Fig. 2 shows a cross member 125 arranged substantially transversely to the forward direction of travel 120 of the motor vehicle 100, which is fastened to two shock absorbers 130 arranged substantially longitudinally to the forward direction of travel 120. The shock absorbers 130 are formed from sheet metal and arranged parallel and spaced from one another, wherein the shock absorbers 130 are connected to an engine mount (not shown here) or the supporting structure 105 of the motor vehicle 100.

[0034] The cross member 125 is part of a crash management system of the motor vehicle 100 (not shown in detail here). The cross member 125 comprises a plurality of sections, namely a longitudinal section 135 which is located between the two connection points of the cross member 125 to the shock absorbers 130, a first projecting section 140 which extends at one end of the longitudinal section 135 from the connection point of the cross member 125 to the first shock absorber 130 to the left or to the left side of the vehicle with respect to the forward direction of travel 120, and a second projecting section 145 which extends on the opposite side of the longitudinal section 135 from the connection point of the cross member 125 to the other shock absorber 130 to the right or to the right side of the vehicle with respect to the forward direction of travel 120. The respective projecting section 140, 145 projects over the associated shock absorber 130 in the assembled state and thus protrudes from it.In contrast, the longitudinal section 135 is connected to the shock absorbers 130 at both ends when the bumper system 115 is assembled. The longitudinal section 135 and the respective projecting section 140, 145 merge into one another, with the boundary between the longitudinal section 140 and the respective projecting section 140, 145 being defined by the corresponding shock absorber 130 or the connection point to the respective shock absorber 130. The bumper system 115 is designed to be mirror-symmetrical about a vehicle's longitudinal axis 150.

[0035] The cross member 125 is Fig. 3, in which only one of the shock absorbers 130 with the cross member 125 connected to it is shown as an example in a state after assembly and before a collision or impact with a barrier, in conjunction with the Fig. 2 and Fig. 4 is formed in two parts from a profile 300 in the form of a hat profile, which is open on one side in cross-section and in the forward direction of travel 120 of the motor vehicle 100, and a locking plate 200 closing the profile 300. The locking plate 200 and the profile 300 are at least partially connected to one another by a material bond, for example, glued and / or welded.

[0036] The cross member 125 is Fig. 2 to Fig. 4 asymmetrically and eccentrically attached to the shock absorbers 130. After Fig. 3, a vertical distance 305 between an axis of symmetry 310 of the profile 300 and a central axis 315 of the shock absorber 130 is at least 5% of the height 320 of the shock absorber 130.

[0037] After Fig. 2 to Fig. 4, in the area of ​​the respective shock absorber 130, a tab 205 is integrally formed on an upper side of the striking plate 200, wherein the respective tab 205 is bent backwards or diagonally upwards to the left at an obtuse angle, here approximately 45°, relative to the forward direction of travel 120 relative to the rest of the striking plate 200 and is connected to the associated shock absorber 130, in particular welded thereto. The shock absorber 130 is beveled on the side facing the cross member 125 in order to accommodate the associated tab 205. The transition between the striking plate 200 and the tabs 205 is formed by a kink 210. The striking plate 200 and the respective tab 205 are welded to the associated shock absorber 130.

[0038] In the event of a barrier impacting the bumper system 115, the off-center integration and force introduction of the cross member 125 to the shock absorbers 130 leads from an initial situation to Fig. 3 to a torque introduction by the Fig. 1, which allows the cross member 125 to rotate about the vehicle's transverse axis 155. Here, the cross member 125 deflects downwards and rotates clockwise according to the arrow 400. The deformation behavior of the cross member 125 is shown in Fig. 4. Due to the impact absorber 130 being beveled in the area of ​​the tab 205 and the striker plate 200 in front of it with the respective tab 205, the angle 405 between the tab 205 and the remaining striker plate 200 is increased in the event of crash-related twisting of the cross member 125, so that the area acting on the MPDB barrier is increased, which in turn allows the respective impact absorber 130 to fold more effectively. This improves the result of the analysis of the MPDB barrier.

[0039] It should be explicitly pointed out that everything about the shock absorber 130 according to Fig. 3 and Fig. 4 and the corresponding connection to the cross member 125, what has been said applies equally to the other shock absorber 130 and the corresponding connection to the cross member 125 and is applicable accordingly. Reference symbol 100 motor vehicles 105 Supporting structure 110 wheel 115 bumper system 120 Forward direction of the motor vehicle 125 cross members 130 shock absorbers 135 Longitudinal section of the cross member 140 first projecting section of the cross member 145 second projecting section of the cross member 150 vehicle longitudinal axis 155 Vehicle transverse axle 200 Cross member strike plate 205 tab 210 kink 300 Profile of the cross member 305 distance 310 Axis of symmetry of the profile 315 Center axis of the shock absorber 320 Height of the shock absorber 400 arrows 405 angles

Claims

[1] Bumper system (115) for a motor vehicle (100), - comprising a cross member (125) arranged substantially transversely to the forward direction of travel (120) of the motor vehicle (100), - which is fastened asymmetrically and off-center to two shock absorbers (130) arranged substantially longitudinally to the forward direction of travel of the motor vehicle (100) in such a way that, when viewed in cross section through the cross member (125), in the region of the respective shock absorber (130) - an axis of symmetry of the cross member (125) - from a central axis of the respective shock absorber (130) - has a vertical distance greater than 5 percent of the height (320) over which the respective shock absorber (130) extends, - wherein the cross member (125) - a strike plate (200) and - a profile (300) arranged behind the locking plate (200) in the forward direction (120) of the motor vehicle (100), - wherein in the area of ​​the shock absorbers (130) on the strike plate (200) there is arranged a tab (205) which - bent backwards at an obtuse angle relative to the remaining locking plate (200) in relation to the forward direction of travel (120) of the motor vehicle (100) and - is connected to the associated shock absorber (130), characterized by , - that the profile (300) of the cross member (125) has a height extension which lies entirely within the height (320) over which the respective shock absorber (130) extends, and - that the respective shock absorber (130) reaches up to the striking plate (200) at its vertical end of this height (320) opposite the tab (205). [2] Bumper system (115) according to claim 1, wherein - an axis of symmetry of the profile (300) of the cross member (125) - from the center axis of the respective shock absorber (130) - has a vertical distance that is greater than 5 percent of the height (320) over which the respective shock absorber (130) extends. [3] Bumper system (115) according to claim 1 or 2, wherein the region of the striker plate (200) is recessed between the tabs (205). [4] Bumper system (115) according to one of the preceding claims, wherein - the cross member (125), in particular the profile (300) of the cross member (125), is connected vertically downwards to the respective shock absorber (130) and - the tabs (205) protrude upwards over the strike plate (200). [5] Bumper system (115) according to one of the preceding claims, wherein the tabs (205) are upwardly projecting, angled sections of the striker plate (200) by forming. [6] Bumper system (115) according to one of the preceding claims, wherein the cross member (125) is made of two parts - the profile (300) which is open on one side in cross-section and in the forward direction of travel (120) of the motor vehicle and - the locking plate (200) is designed to at least partially close the profile (300). [7] Bumper system (115) according to one of the preceding claims, wherein the profile (300) is a hat profile. [8] Bumper system (115) according to one of the preceding claims, wherein the tabs (205) are integrally connected to the striker plate (200). [9] Bumper system (115) according to one of the preceding claims, wherein the locking plate (200) and the tabs (205) are integrally connected to the associated shock absorber (130) and / or the locking plate (200) and the profile (300) are integrally connected to one another at least in sections. [10] Motor vehicle (100) comprising one or two bumper systems (115) according to one of the preceding claims.

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