Bumper system for a motor vehicle

Abstract

The invention relates to a bumper system for a motor vehicle, wherein the motor vehicle has a radiator module and wherein a pedestrian protection cross member is attached to the motor vehicle body by means of connecting elements. The connecting elements are designed and attached to the vehicle body in such a way that a force resulting from a frontal impact of the vehicle and acting on the pedestrian protection crossbeam in the longitudinal direction of the vehicle, which causes a plastic deformation of the arrangement, causes a pivoting movement of the pedestrian protection crossbeam in the longitudinal direction of the vehicle to the rear and in the vertical direction of the vehicle initially downwards.

Description

[0001] The invention relates to a bumper system for a motor vehicle having the features of the preamble of claim 1. In modern motor vehicles, there is a desire not only to protect the occupants of the vehicle in the event of an accident, but also to minimize damage to other road users. These other road users include, in particular, pedestrians. Unlike the occupants of the vehicle, who are protected by the passenger compartment of the vehicle, pedestrians are particularly vulnerable road users. Even rear-end collisions with a pedestrian at comparatively low speed can result in severe injuries and / or death. There is therefore a desire to design motor vehicles, particularly in their frontal area, in such a way that the injuries suffered by pedestrians hit by a motor vehicle are as minimal as possible.

[0002] In a typical accident, the pedestrian is initially struck in the leg area by the front of the vehicle. The pedestrian's body then rotates and is thrown onto the hood of the vehicle. Such accident scenarios can result in serious knee injuries, particularly in vehicles with a relatively high bumper cross member positioned at the front of the vehicle. Modern vehicle fronts are generally designed so that relatively flexible plastic trim elements conceal the actual bumper assembly. The key element of this assembly is usually a bumper cross member, which is attached to the side members of the vehicle body by means of deformation elements, so-called "crash boxes". However, different designs are conceivable.In the event of a collision between a vehicle and a pedestrian, this bumper cross member is the first "hard" element of the vehicle's front end to strike the pedestrian. If the pedestrian is struck by this element at too great a height, an unfavorable impact on the pedestrian's legs occurs.

[0003] In these cases, modern vehicle fronts therefore regularly feature pedestrian protection cross members designed to impact the pedestrian as low as possible at the foot's edge, thus initiating the pedestrian's rotation early on. Figuratively speaking, this pedestrian protection cross member "pushes" the pedestrian in an area below their knees. Such pedestrian protection cross members are also referred to as lower cross members or pedestrian protection cross members. Similar to a bumper cross member, it is a beam running transversely across the vehicle, made of a resilient material, usually a metallic material, and is usually located behind the front fascia.

[0004] According to the state of the art, such pedestrian protection cross members are arranged below the bumper cross member.

[0005] The pedestrian protection cross member can, for example, be connected to the bumper cross member by means of essentially vertically running connecting elements and thus fastened to the bumper cross member. Such an arrangement is known, for example, from DE 10 2016 013 877 A1. A disadvantage of such an arrangement, however, is that in the event of an accident, the pedestrian protection cross member can be displaced rearward as a result of the deformation of the vehicle front and / or, due to the deformation of the connecting elements, can perform a pivoting movement relative to the rest of the vehicle front, directed rearward in the longitudinal direction of the vehicle and upward in the vertical direction of the vehicle. In this case, the pedestrian protection cross member can be displaced or pivoted into a radiator module typically arranged behind the pedestrian protection cross member.These are the types of accidents simulated in insurance tests. The resulting damage then affects the radiator module. This leads to higher repair costs in the event of such accidents and thus usually results in a higher comprehensive insurance rating for the vehicle.

[0006] Other bumper systems of the type in question are known from the publications FR 2 920 725 A1, FR 2 890 621 A1, DE 10 2017 200 113 A1, DE 10 2014 011 134 A1, DE 10 2005 018 348 A1, DE 10 2006 041 112 A1, DE 10 2014 016 379 B4, and DE 10 2004 030 794 A1. However, the bumper systems shown in these publications do not offer a solution to the problem described above of the possible displacement and / or pivoting of the pedestrian protection cross member into the radiator module.

[0007] The invention is therefore based on the object of providing a bumper system for a motor vehicle in which the risk of damage to the radiator module of the motor vehicle in the event of an accident is reduced.

[0008] The object is achieved according to the invention with the features of the independent claims. Further practical embodiments and advantages of the invention are described in conjunction with the dependent claims.

[0009] The bumper system has connecting elements by means of which the pedestrian protection cross member is attached to the vehicle body. The connecting elements are designed and attached to the vehicle body in such a way that a force resulting from a frontal impact of the vehicle and acting in the longitudinal direction of the vehicle on the pedestrian protection cross member, which causes plastic deformation of the assembly, causes a pivoting movement of the pedestrian protection cross member, directed rearward in the longitudinal direction of the vehicle and initially downward in the vertical direction of the vehicle.

[0010] It has been shown that a suitable design of the arrangement can ensure that the pivoting movement performed by the pedestrian protection cross member due to plastic deformation, in particular of the connecting elements and the areas of the connection between the connecting elements and the vehicle body, is not upwards and backwards with respect to the vehicle, but rather downwards and backwards. This causes the pedestrian protection cross member to lower before it reaches the radiator module arranged behind the pedestrian protection cross member as the front of the vehicle deforms. In practice, this can prevent damage to the radiator module in many accidents involving a head-on collision of a vehicle with an obstacle. This has a positive effect on repair costs in such accidents and therefore enables a more favorable comprehensive insurance classification for the vehicle.

[0011] In particular, the pivoting movement results in the pedestrian protection cross members and / or the connecting elements being moved beneath the radiator module and / or laterally past the radiator module as a result of the pivoting movement. According to the invention, the pedestrian protection cross member is moved beneath the radiator module. The connecting elements are, in particular, moved laterally past the radiator module. This allows the pedestrian protection cross members and connecting elements to pass the radiator module and, at least partially, to be moved to the height of the radiator module in the longitudinal direction of the vehicle or even beyond it during the deformation of the vehicle front.

[0012] Such plastic deformation is brought about in particular by the design of the connecting elements and the positioning of the fastening of the connecting elements to the body. The connecting elements are in particular connecting struts. This means connecting elements that extend in particular in a main direction of extension. The connecting elements extend from the pedestrian protection cross member in particular backwards in the longitudinal direction of the motor vehicle and upwards in the vertical direction of the motor vehicle. As a result, the struts and their connection to the motor vehicle body are located above and behind the pedestrian protection cross member. A pivot axis that results from a plastic deformation of the connecting elements orThe area of ​​the connection of the connecting elements to the vehicle body is located behind the pedestrian protection cross member in the longitudinal direction of the vehicle and above it in the vertical direction of the vehicle.

[0013] The connecting elements can extend, in particular, diagonally upwards and backwards relative to the longitudinal and vertical directions of the motor vehicle at an angle of at least 25° to the vertical direction of the motor vehicle. In this context, the direction of extension refers, in particular, to the direction from the connection between the connecting element and the pedestrian protection cross member to the connecting element and the vehicle body. A corresponding diagonal extension of the connecting elements enables a corresponding downward directional component of the pivoting movement.

[0014] The connecting elements can, in particular, each be connected to a deformation element that connects a bumper cross member to the longitudinal members of the vehicle body. Such deformation elements, also known as crash boxes, deform even in a relatively moderate frontal impact and therefore dissipate as much impact energy as possible through their plastic deformation. The aim is to ensure that in moderate frontal accidents, only the deformation elements are initially destroyed before the longitudinal members undergo plastic deformation, which would result in significantly higher repair costs or even total loss.Therefore, the connection of the connecting elements to the deformation element has the advantage that in the event of a frontal impact of the type in question, the connecting elements transmit the forces into the deformation elements and thus into a component of the vehicle body which is in any case designed to be deformed in such an accident.

[0015] The connecting elements are connected to the deformation elements, particularly in the rear 50% of the extension of the deformation elements in the longitudinal direction of the vehicle. The connection of the connecting elements in the rear area of ​​the deformation elements to the deformation elements means that the pivot axis of the pedestrian protection cross member's pivoting movement can also be shifted rearward relative to the longitudinal direction of the vehicle, which reinforces the downward movement component of the pedestrian protection cross member's pivoting movement.

[0016] The connection between a respective connecting element and the corresponding deformation element can, in particular, be designed such that the connecting elements result in an asymmetrical strengthening and / or weakening of the deformation element in the transverse direction of the vehicle. Thus, the force introduction, particularly on the inner sides of the deformation elements or on the outer sides of the deformation elements (in the transverse direction of the vehicle), can outweigh the force introduction on the other side of the deformation elements. This allows the pivoting movement of the pedestrian protection cross member to be additionally used to influence the buckling behavior of the longitudinal members in more serious accidents.By asymmetrically strengthening and / or weakening the deformation elements, the deformation can be influenced such that the forces transmitted by the deformation elements into the vehicle's longitudinal members have an inward or outward component. This can induce a desired buckling behavior of the longitudinal members in severe accidents.

[0017] The connecting elements can each have a connecting region with which they are each connected to a deformation element, wherein the connecting regions encompass the deformation elements in a fork-like manner. With such fork-shaped connecting regions, good force introduction from the connecting element into the deformation element can be achieved. In particular, such a design is suitable for the implementation of asymmetric force introduction. For this purpose, for example, the two sides of the connecting region that encompass the deformation element in a fork-like manner can differ in their design. In particular, one side of the fork-shaped connecting region can be longer than the other side. This allows an asymmetric reinforcement and / or weakening of the deformation element to be implemented in a simple manner.

[0018] The parallel projections of the connecting elements, especially in the longitudinal direction, do not spatially overlap with the parallel projection of the cooler module in the longitudinal direction. This allows the connecting areas to pivot backward while deforming and pass laterally through the cooler module without damaging it.

[0019] The pedestrian protection cross member is arranged longitudinally of the vehicle at at least substantially the same height and / or in front of the bumper cross member. The respective position of the foremost point of the pedestrian protection cross member and the bumper cross member is particularly important for this. Such an arrangement results in the pedestrian protection cross member striking the pedestrian—at least with a high probability—before the bumper cross member, thus triggering a rotational movement of the pedestrian's body at an early stage.

[0020] Further practical embodiments of the invention are described below in conjunction with the drawings. They show: Fig. 1 a bumper system according to the state of the art, Fig. 2 an exemplary bumper system according to the present invention, Fig. 3 a schematic representation of the comparison of the pivoting movements of the pedestrian protection cross member in the bumper systems from the Fig. 1 and Fig. 2, Fig. 4 a front view of an exemplary bumper system and a radiator module, Fig. 5 an exemplary perspective view of the arrangement from Fig. 4, Fig. 6 a perspective view of the arrangement of Fig. 4 after deformation due to an accident, Fig. 7 a detailed view of the connection of the pedestrian protection cross member of the arrangement from Fig. 4 on the vehicle body.

[0021] In the Fig. In the prior art bumper system 10 illustrated by way of example in Figure 1, a pedestrian protection cross member 12 is attached to a motor vehicle body by means of substantially vertically extending connecting elements 14. The connecting elements 14 can be connected, as in the example shown, to a bumper cross member 16, below which the pedestrian protection cross member 12 is arranged. The bumper cross member 16 is connected to the longitudinal members (not shown) of a motor vehicle body by means of deformation elements 18.

[0022] The Fig. The exemplary bumper system 10 according to the present invention shown in Figure 2 also includes a pedestrian protection cross member 12 that is attached to a motor vehicle body by means of connecting elements 14. The pedestrian protection cross member 12 can be constructed as shown in Fig. 2, can also be arranged below a bumper cross member 16, which can be attached to longitudinal members of a motor vehicle body (also not shown) by means of deformation elements 18. In Fig. However, in the example shown in Figure 2, the connecting elements 14 are designed and fastened to the motor vehicle body in such a way that a force resulting from a frontal impact of the motor vehicle and acting on the pedestrian protection cross member 12 in the longitudinal direction X of the motor vehicle, which force causes a plastic deformation of the bumper system 10, causes a pivoting movement of the pedestrian protection cross member 12 directed rearward in the longitudinal direction X of the motor vehicle and initially downward in the vertical direction Z of the motor vehicle. In the example shown, this is made possible in particular by the fact that the connecting elements 14 are connected to the deformation elements 18. The connection is located in particular in the region of the rear 50% of the extension of the deformation elements 18 in the longitudinal direction X of the motor vehicle.As a result, the connecting elements 14, which can be designed as connecting struts as in the example shown, extend from the pedestrian protection cross member 12 in the longitudinal direction X of the motor vehicle to the rear and in the vertical direction Z of the motor vehicle upwards.

[0023] In the Fig. 3 is a schematic representation of how the pivoting movement of the pedestrian protection cross member 12 in a bumper system 10, as shown for example in Fig. 2, of a bumper system 10, as shown for example in Fig. 1 is shown.

[0024] In the schematic cross-section, in addition to the pedestrian protection cross member 12, which is attached to a deformation element 18 by means of connecting elements 14, the radiator module 20 is also shown, which is arranged behind the pedestrian protection cross member 12 and the bumper cross member 16 in the vehicle's longitudinal direction X. Also shown are cladding elements 22, which form the outer skin of the vehicle front. In a pedestrian protection cross member 12 according to the prior art, the pivot axis 24 of the pivoting movement of the pedestrian protection cross member 12 would be located above the pedestrian protection cross member 12. The resulting pivoting movement of the pedestrian protection cross member 12 would correspond—at least approximately—to the circular path 26.It is obvious that this pivoting movement, which is initially directed only rearward in the longitudinal direction X of the motor vehicle and subsequently also upward in the vertical direction Z of the motor vehicle, results in the pedestrian protection cross member 12 pivoting into the radiator module 20.

[0025] On the other hand, a pedestrian protection cross member 12 of a bumper system 10, as is shown for example in Fig. 2, pivot about the pivot axis 28 in a corresponding accident scenario. In such a scenario, the pivoting movement of the pedestrian protection cross member 12 about the pivot axis 28 would accordingly correspond—at least approximately—to the circular path 30. The pedestrian protection cross member 12 would therefore execute a pivoting movement that is also directed rearward in the vehicle's longitudinal direction X, but initially downward in the vertical direction Z of the motor vehicle. This enables the pedestrian protection cross member 12 to pivot not along the circular path 26 into the radiator module 20, but rather along the circular path 30 below the radiator module 20.

[0026] In Fig. 4 is a bumper system 10 which essentially corresponds to the Fig. 2, shown from the front in conjunction with an exemplary radiator module 20. The radiator module 20 can, in particular, be arranged behind the pedestrian protection cross member 12 in such a way that the parallel projections of the pedestrian protection cross member 12 and the radiator module 20 overlap in the longitudinal direction X of the motor vehicle, as shown. This means that a rectilinear movement of the pedestrian protection cross member 12 in the longitudinal direction X of the motor vehicle would already result in it colliding with the radiator module 20; however, a pivoting movement with a component directed upwards in the vertical direction Z of the motor vehicle leads to a pivoting of the pedestrian protection cross member 12 into the radiator module 20.

[0027] The cooler module 20 can, as in the example shown, have a heat exchanger element 32, which is attached to a mounting bracket 34. The mounting bracket 34 can, as in the example shown, be frame-shaped and enclose the heat exchanger element 32. Modern mounting brackets 34 can, as in the example shown, have a complex structural design and, in particular, be made of a plastic. Furthermore, the mounting bracket 34 can serve to attach a variety of components of the motor vehicle in the front area. This makes the mounting bracket 34 of the cooler module 20 a component worthy of protection in the event of deformation of the motor vehicle front.

[0028] In the Fig. 5 is the Fig. 4, the bumper system 10 is shown again in a slightly perspective view. To allow a comparison, the Fig. 6 the same bumper system 10 from the Fig. 4 and Fig. 5 in a state deformed by a frontal impact. It can be seen that on the side of the impact, the connecting element 14 has been deformed in the region of its connection to the deformation element 18. As a result of this deformation, a pivot axis has formed at this point, around which the pedestrian protection cross member 12 performed a corresponding pivoting movement on its left side, the side affected by the frontal impact and the deformation. The pivoting movement was directed rearward in the longitudinal direction X of the motor vehicle and initially downward in the vertical direction Z of the motor vehicle. This enabled the pedestrian protection cross member 12 to pivot under the radiator module 20 and pass the radiator module 20, in particular the mounting bracket 34, by being moved under the radiator module 20 or through the radiator module 20.Accordingly, the connecting element 14 could pivot laterally past the cooler module 20, in particular past the mounting bracket 34 of the cooler module 20. This is made possible in particular by the fact that—as shown in . Fig. 4 - the parallel projection of the radiator module 20 and the parallel projection of the connecting elements 14 in the longitudinal direction X of the motor vehicle do not overlap.

[0029] In Fig. 7 is the connection of a connecting element 14 with a deformation element 18 of the exemplary, in the Fig.4 to 6 is shown again in detail. It can be seen that the connecting element 14 has a connecting region 36 which surrounds the deformation element 18 in a fork-like manner. The connecting region 36 can be designed asymmetrically in the transverse direction Y of the motor vehicle, as in the example shown. This can ensure that, when the bumper system 10 is deformed, an asymmetric deformation of the deformation element 18 is brought about due to the asymmetric reinforcement and / or weakening by the connecting element 14. This can influence the transmission of forces arising during a frontal impact via the deformation element 18 into the longitudinal members (not shown) in such a way that, in the event of a serious accident, a desired buckling behavior of the longitudinal members is triggered.

[0030] The features of the invention disclosed in the present description, the drawings, and the claims may be essential, both individually and in any combination, for the realization of the invention in its various embodiments. The invention may be varied within the scope of the claims and taking into account the knowledge of the person skilled in the art. List of reference symbols 10 Bumper system 12 pedestrian protection cross members 14 Connecting element 16 bumper cross members 18 deformation elements 20 cooler module 22 cladding elements 24 swivel axis 26 circular orbit 28 Swivel axis 30 circular path 32 Heat exchanger element 34 mounting brackets 36 Connection area X Longitudinal direction of the vehicle Y Transverse direction of the vehicle Z Vertical direction of the vehicle

Claims

[1] Bumper system (10) for a motor vehicle, wherein the motor vehicle has a radiator module, wherein a pedestrian protection cross member (12) is fastened to the motor vehicle body by means of connecting elements (14), wherein the connecting elements (14) are designed and fastened to the motor vehicle body in such a way that a force resulting from a frontal impact of the motor vehicle and acting in the longitudinal direction (X) of the motor vehicle on the pedestrian protection cross member (12), which force causes a plastic deformation of the arrangement (10), causes a pivoting movement of the pedestrian protection cross member (12) directed rearward in the longitudinal direction (X) of the motor vehicle and initially downward in the vertical direction (Z) of the motor vehicle, characterized by that the pedestrian protection cross member (12) is moved under the radiator module (20) by the pivoting movement. [2] Bumper system (10) according to claim 1, characterized bythat the connecting elements (14) are designed as connecting struts which extend from the pedestrian protection cross member (12) in the longitudinal direction (X) of the motor vehicle to the rear and in the vertical direction (Z) of the motor vehicle upwards. [3] Bumper system (10) according to claim 1 or 2, characterized by that the connecting elements (14) are each connected to a deformation element (18) which connects a bumper cross member (16) to longitudinal members of the motor vehicle body. [4] Bumper system (10) according to claim 3, characterized by that the connecting elements (14) are connected to the deformation elements (18) in the region of the rear 50% of the extension of the deformation elements (18) in the longitudinal direction (X) of the motor vehicle. [5] Bumper system (10) according to claim 3 or 4, characterized bythat the connection between a respective connecting element (14) and the corresponding deformation element (18) is designed in such a way that the connecting elements (14) result in an asymmetric reinforcement and / or weakening of the deformation element (18) in the transverse direction (Y) of the motor vehicle. [6] Bumper system (10) according to claim 5, characterized by that the asymmetric reinforcement and / or weakening influences the buckling behavior of the longitudinal members. [7] Bumper system (10) according to one of claims 3 to 6, characterized by that the connecting elements (14) each have a connecting region (36) with which they are each connected to a deformation element (18), wherein the connecting regions (36) encompass the deformation elements (18) in a fork-like manner. [8] Bumper system (10) according to one of the preceding claims, characterized bythat the parallel projections of the connecting elements (14) in the longitudinal direction (X) do not have any spatial overlaps with the parallel projection of the cooler module (20) in the longitudinal direction (X). [9] Bumper system (10) according to one of the preceding claims, characterized by that the connecting elements (14) are moved laterally past the cooler module (20) by the pivoting movement. [10] Bumper system (10) according to one of the preceding claims, characterized by that the pedestrian protection cross member (12) is arranged in the longitudinal direction (X) of the motor vehicle at the same height and / or in front of the bumper cross member (16).

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