Pedestrian protection device

Abstract

Pedestrian protection device (10) in the front of a motor vehicle, comprising - an upper support structure (18) connected to a chassis of the motor vehicle, - a shock absorber (20) arranged below the upper support structure (18) and projecting forward beyond the chassis and - coupling elements by means of which the shock absorber (20) is coupled to the upper support structure (18), characterized by that the shock absorber (20) is designed as a foam body (22) fixed in a form-fitting manner to a cross member (12) of the chassis and the upper support structure (18) is fixed indirectly via a plastic base body (16) fixed to the chassis, wherein the coupling elements are designed as vertical structures (223) formed integrally on the foam body (22), which are supported horizontally movable against the upper support structure (18) via hardened sliding surfaces (224).

Description

[0001] The invention relates to a pedestrian protection device in the front of a motor vehicle, comprising - an upper support structure connected to a chassis of the motor vehicle, - a shock absorber located below the upper support structure and projecting forward beyond the chassis and - Coupling elements by means of which the shock absorber is coupled to the upper support structure.

[0002] Such a pedestrian protection device is known from US 2004 / 0238 256 A1.

[0003] To minimize consequential damage in the event of a collision between a motor vehicle and a pedestrian, it is common practice to equip motor vehicles with shock-absorbing bumpers in the front, collision-prone area, the so-called front end. In modern vehicles, these can be very complex structures designed to dissipate occurring forces and / or convert them into deformation energy. At the same time, they can be designed to induce buckling and rolling movements to prevent serious injuries as far as possible.

[0004] From the aforementioned generic publication, a tray-like shock absorber is known that projects forward beyond the rest of the motor vehicle. It essentially consists of a perforated plate, the material of which is not further specified, with a surrounding foam edge. The foam edge is intended to prevent cuts caused by the plate, while the perforation of the plate forms a deformation zone into which impact energy is directed and converted into deformation energy. This known shock absorber is firmly connected to the chassis of the motor vehicle. In particular, it is firmly bolted to the ends of longitudinal tubes of a vehicle frame via clamps protruding from its rear edge.These tube ends thus form an upper support structure, below which and projecting forward above it the tray-like shock absorber is arranged, wherein the coupling between said support structure and said shock absorber is realized by the clamps firmly fixed to both said elements as coupling elements.

[0005] Those skilled in the art will understand that, in the context of this description, the term "chassis" is not limited to vehicle frames. Rather, it includes any supporting structures of motor vehicles. This particularly applies to the currently common design of motor vehicles with a self-supporting body. Likewise, those skilled in the art will understand that directional and relative positioning information in the description always refers to the final assembly state in the operational motor vehicle.

[0006] The well-known pedestrian protection device has proven to be in need of improvement with regard to minimizing damage in the event of a collision.

[0007] It is therefore the object of the present invention to provide a pedestrian protection device which is improved in terms of its protective effect.

[0008] This object is achieved in conjunction with the features of the preamble of claim 1 in that the shock absorber is designed as a foam body which is positively fixed to a cross member of the chassis and the upper support structure is fixed indirectly via a plastic base body which is fixed to the chassis, wherein the coupling elements are designed as vertical structures which are integrally formed on the foam body and which are supported horizontally movable against the upper support structure via hardened sliding surfaces.

[0009] The invention comprises several advantageously interacting aspects. First, the shock absorber is designed as a foam body, i.e., a body formed three-dimensionally from a deformable foam. Such a foam body exhibits a particularly high, largely direction-independent ability to convert impact energy into deformation energy, which accommodates the considerable number of possible impact constellations that vary depending on the collision location and direction. This foam body is directly and positively fixed to a cross member belonging to the chassis. This ensures a particularly reliable relative fixation of the chassis and shock absorber.In order to prevent the foam body from folding upwards - for example in the event of breakage in the event of a collision - and thereby losing its effectiveness (as is fundamentally possible with the prior art), upwardly projecting coupling elements are provided with which the foam body can be braced upwards against an upper support structure. This, in turn, is not attached directly to the chassis, but only indirectly via a plastic base body fixed to the chassis, which also serves as the mounting base for other functional elements, such as headlights, radiator grille, etc. According to the invention, the coupling elements, via which the shock absorber is braced against the upper support structure, are molded integrally onto the foam body. In particular, they represent vertical structures made of the same material as the foam body. The shaping of foam bodies can be of almost any complexity using methods known in the art.Technically, the one-piece and, in particular, uniform material design of the vertical structures together with the actual shock absorber is therefore easily feasible. A key advantage of this measure is the elimination of separate coupling elements, which simplifies procurement, production, and assembly, making them more cost-effective. Finally, a further aspect of the invention is that the coupling elements—unlike the prior art—do not represent a rigid connection between the shock absorber and the upper support structure, but rather are attached to the latter in a horizontally movable manner. In practice, this results in vibration decoupling, which is acoustically advantageous and also creates increased flexibility of the structure, especially in lateral collision events.However, since the foam material from which the supporting vertical structures are made is not particularly resistant to force, the contact surfaces between the vertical structures and the upper support structure are at risk of significant wear. In particular, there is a risk that the upper support structure will "work" into the sliding surfaces of the vertical structures. To counteract this, the invention additionally provides for said sliding surfaces to be harder than the rest of the foam material. In this way, vertical support of the shock absorber can be achieved while simultaneously decoupling horizontal vibrations from the upper support structure with virtually no wear.

[0010] Preferably, the upper support structure is designed as a series of plastic brackets that are horizontally locked to the plastic base body. This is advantageous in terms of assembly. Furthermore, the required rigidity or flexibility can be optimized in specific areas across the entire vehicle width.

[0011] In a preferred embodiment of the invention, the sliding surfaces are designed as plastic plates embedded in the foam material of the foam body or glued onto the foam material. These can be made, in particular, of polytetrafluoroethylene (PTFE). PTFE is an extremely low-friction, durable material. Sliding surfaces equipped in this way can reliably prevent the upper support structure from "working" into the foam material of the vertical superstructures, even during horizontal sliding processes subjected to vertical forces, such as those that occur during operational vibrations within the motor vehicle throughout its entire service life.

[0012] Two variants have proven particularly advantageous for the design of the cross member. In the first variant, the cross member has a profile that is open at the front and forms a receiving groove, and the foam body is designed as a bead extending in front of and parallel to the cross member. A web of the foam body, which adjoins the bead at the rear and is integral with the bead, projects into the receiving groove of the cross member in a form-fitting manner. This type of fixation of the foam body in the cross member maximizes the contact surface between the foam body and the cross member, whereby the fundamentally form-fitting fixation can be reinforced by additional friction and / or force-lock components.

[0013] A preferred embodiment of this variant provides that the cross member has a vertically projecting cross member flange adjoining the upper edge of the receiving groove, which is engaged behind by rearward, angular projections of the vertical structures. In other words, the vertical structures have a hook-like profile in longitudinal section, which engages around an upwardly projecting edge of the cross member. During assembly, said angular projections can initially be slipped over said cross member flange, with the foam body itself still positioned at an angle to its final assembly position, so that its web does not yet (fully) protrude into the receiving groove of the cross member. In this state, the angular projections of the vertical structures can be elastically bent.The bead and web of the foam body are then pivoted backwards together around a pivot axis, which lies approximately in the area of the cross member flange, so that the web is pushed into the receiving groove of the cross member, whereby the elastically bent hooks of the angular projections of the vertical structures relax and the hook-like profile of said projections grips the cross member flange on both sides in the final assembly position.

[0014] In an alternative variant, however, it can be provided that the cross member is designed as a hollow profile that is predominantly closed at the front by a closing wall, and the foam body is designed as a bead that extends in front of and parallel to the cross member, wherein locking bolts that are connected to the bead at the rear and in one piece and each have a narrower bolt neck and a wide bolt head, penetrate corresponding locking openings in the closing wall. In other words, instead of the web of the first variant mentioned above, mushroom-shaped locking bolts are formed on the bead, which form-fit through corresponding locking openings in the closing wall of the cross member. In particular, said locking openings should have a cross section that is larger than the cross section of the bolt neck and smaller than the cross section of the bolt head. During assembly, i.e.When the locking pins are inserted into the locking openings, the pin head temporarily deforms elastically so that it can be pushed through the locking opening. It then expands elastically again, preventing disassembly with a reversed movement sequence through positive locking.

[0015] Further features and advantages of the invention will become apparent from the following specific description and drawings.

[0016] They show: Fig. 1: a partially sectioned, perspective view of a first embodiment of a pedestrian protection device according to the invention, Fig. 2: a front view of the pedestrian protection device of Fig. 1, Fig. 3: a sectional view of the pedestrian protection device of Fig. 1 and Fig. 4: a sectional view of an alternative embodiment of a pedestrian protection device according to the invention.

[0017] The same reference numerals in the figures indicate the same or analogous elements.

[0018] Fig. 1 shows a partially sectioned, perspective view of a first embodiment of a pedestrian protection device 10 according to the invention, which is positioned in the front of a motor vehicle (not otherwise shown).

[0019] The motor vehicle has, as a component of the pedestrian protection device 10, a cross member 12 designed as a profiled sheet, which is rigidly connected to the chassis of the motor vehicle (not shown), in particular constituting a component thereof. Furthermore, a plastic base body 16 is connected to the chassis (in a manner not shown in detail), which serves as an assembly base for various functional elements of the motor vehicle, of which, however, only an upper support structure 18 is shown here. In the embodiment shown, this essentially consists of a series of plastic brackets 181, which are individually locked to the plastic base body 16. The plastic brackets 181, or the upper support structure 18, are positioned at a distance above the cross member 12.

[0020] Furthermore, the pedestrian protection device 10 comprises a shock absorber 20, which is designed in particular as a one-piece, uniform foam body 22.

[0021] The foam body 22 essentially has three functionally different areas. A bead 221 extending in front of and parallel to the cross member 12 serves essentially to absorb energy in the event of a collision. The term "bead" is, as can be seen in particular from the Fig. 1 and Fig. 3, is to be understood broadly and can also include complex shapes.

[0022] In any case, however, its vertical extension is greater than that of the web 222 adjoining it to the rear, which forms a second functional area of the foam body and essentially serves to fix the foam body 22 in the cross member 12. In this embodiment, the cross member 12 is designed as a hollow profile open at the front, as shown in the Fig. 1 and Fig. 3. It forms a receiving groove that is open to the front. In the final assembly position, the web 222 essentially fills the entire receiving groove. By appropriately dimensioning the web 222 and the cross member 12 or the receiving groove, the positive connection between the web 222 and the receiving groove can be reinforced by friction and / or force-lock components. In particular, the web 222 can be clamped in the receiving groove.

[0023] A third functional area of the foam body 22 is represented by its vertical structures 223, which extend essentially vertically upwards from the upper side of the bead 221. There they are supported against the upper support structure 18. The direct contact area of the vertical structures 223 with the upper support structure 18 is designed as a plurality of hardened sliding surfaces, which are in particular formed as small plates made of PTFE, another plastic or metal, embedded in the foam material of the foam body 22, in particular the vertical structures 223. These sliding surfaces 224 allow, on the one hand, a horizontal relative movement between the foam body 22 and the upper support structure 18 and, on the other hand, ensure that the foam body 22 is supported in the vertical direction against the upper support structure 181. Due to the special, hardened design of the sliding surfaces 224, abrasion orprevents the plastic brackets 181 of the upper support structure 18 from “working in” the upper sides of the vertical structures 223.

[0024] In the Fig. 1 and Fig. In the embodiment shown in Figure 3, the vertical structures 223 are provided with rearwardly angled projections 225, which engage behind a cross member flange 121, i.e., an upper edge strip of the cross member 12. This provides additional, positive-locking positioning of the foam body 22 in the longitudinal direction of the motor vehicle relative to the cross member 12.

[0025] Fig. 2 shows the pedestrian protection device of the Fig. 1 and Fig. 3 in frontal view, where the Fig. 1 and Fig. 3 illustrate the aspects of the invention more clearly.

[0026] Fig. 4 shows an alternative embodiment of a pedestrian protection device according to the invention, the special feature of which is particularly evident in comparison with the Fig. 3 and Fig. 4. In this embodiment, the cross member 12 is designed as a closed hollow profile and in particular has a closing wall 122 closing off its cavity at the front. Due to the closing wall 122, it is not possible to insert a volume-filling web 222 of the foam body 22 into the cavity of the cross member 12. Therefore, the foam body 22 of the embodiment of Fig. 4 instead of a web 222 has a plurality of mushroom-like locking projections 222' which penetrate corresponding locking openings 123 in the closing wall 122 of the cross member 12 and in this way enable a positive fixing, in particular locking, of the foam body 22 on the cross member 12.

[0027] Another difference to the design of Fig.3, the vertical projections 223 serve only for vertical support. In particular, they are not provided with angle- or hook-shaped projections to engage behind the cross member flange 121. In principle, however, the individual aspects of the variants shown can also be easily combined with one another.

[0028] Of course, the embodiments discussed in the specific description and shown in the figures represent only illustrative embodiments of the present invention. In light of the disclosure herein, a broad spectrum of possible variations is available to those skilled in the art. In particular, the specific shape of the bead 221 and the upper support structure 18 is not essential to the invention. Here, the skilled person can certainly make design-motivated modifications to create an individual vehicle silhouette. List of reference symbols 10 Pedestrian protection device 12 cross members 121 Cross member flange 122 Closing wall 123 locking opening 16 plastic base bodies 18 upper support structure 181 plastic brackets 20 shock absorbers 22 foam bodies 221 bulge 222 jetty 222' locking bolt 223 Vertical structure 224 sliding surface 225 lead

Claims

[1] Pedestrian protection device (10) in the front of a motor vehicle, comprising - an upper support structure (18) connected to a chassis of the motor vehicle, - a shock absorber (20) arranged below the upper support structure (18) and projecting forward beyond the chassis, and - coupling elements by means of which the shock absorber (20) is coupled to the upper support structure (18), characterized by , that the shock absorber (20) is designed as a foam body (22) fixed in a form-fitting manner to a cross member (12) of the chassis and the upper support structure (18) is fixed indirectly via a plastic base body (16) fixed to the chassis, wherein the coupling elements are designed as vertical structures (223) formed integrally on the foam body (22), which are supported horizontally movable against the upper support structure (18) via hardened sliding surfaces (224). [2] Pedestrian protection device (10) according to claim 1, characterized by that the upper support structure (18) is designed as a row of plastic brackets (181) locked horizontally next to one another with the plastic base body (16). [3] Pedestrian protection device (10) according to one of the preceding claims, characterized by that the sliding surfaces (224) are designed as plastic plates embedded in the foam material of the foam body (22) or glued onto the foam material. [4] Pedestrian protection device (10) according to one of the preceding claims, characterized by that the sliding surfaces (224) are made of polytetrafluoroethylene. [5] Pedestrian protection device (10) according to one of the preceding claims, characterized bythat the cross member (12) has a profile which is open towards the front and forms a receiving groove, and the foam body (22) is designed as a bead (221) extending in front of and parallel to the cross member (12), wherein a web (222) of the foam body (22) which adjoins the bead (221) at the rear and in one piece projects into the receiving groove of the cross member (12) in a form-fitting manner. [6] Pedestrian protection device (10) according to claim 5, characterized by that the cross member (12) has a vertically projecting cross member flange (121) adjoining the upper groove edge of the receiving groove, which is engaged behind by rear, angular projections (225) of the vertical structures (223). [7] Pedestrian protection device (10) according to one of claims 1 to 4, characterized bythat the cross member (12) is designed as a hollow profile which is predominantly closed at the front by a closing wall (122) and the foam body (22) is designed as a bead (221) extending in front of and parallel to the cross member (12), wherein locking bolts (222'), which adjoin the bead (221) at the rear and in one piece and each have a narrower bolt neck and a wider bolt head, pass through corresponding locking openings (123) in the closing wall (122).

Images