Energy Absorption Device

Abstract

An energy absorption device for a bumper of a motor vehicle has a first deformation element on the front side of the bumper. The first deformation element is a foam shaped part which extends over the width of the bumper and has a density of from 20 to 50 g/l. At least one second deformation element, with a density which is at least 50 g/l higher than the first deformation element, is inserted into the first deformation element.

Claims

1.-14. (canceled)

15. An energy absorption device for a bumper of a vehicle, comprising: a first deformation element, which extends substantially over an entire width of the bumper; and at least one second deformation element, which is arranged on the first deformation element, wherein the first and the second deformation element are made of foam material with different densities, the foam material of the first deformation element has a density which is at least 50 g/l lower than that of the foam material of the second deformation element, and the density of the foam material of the first deformation element is 20 to 50 g/l and the density of the foam material of the second deformation element is 80 to 250 g/l.

16. The energy absorption device according to claim 15, wherein the foam material of the first deformation element has a density which is at least 60 g/l lower than that of the foam material of the second deformation element.

17. The energy absorption device according to claim 15, wherein the foam material of the first deformation element has a density which is at least 70 g/l lower than that of the foam material of the second deformation element.

18. The energy absorption device according to claim 15, wherein the density of the foam material of the second deformation element is 90 to 250 g/l.

19. The energy absorption device according to claim 15, wherein the density of the foam material of the second deformation element (10) is 100 to 250 g/l.

20. The energy absorption device according to claim 15, wherein the second deformation element is inserted in the first deformation element.

21. The energy absorption device according to claim 20, wherein the first deformation element has a cutout for accommodating the second deformation element.

22. The energy absorption device according to claim 15, wherein the second deformation element is arranged on a front side of the first deformation element.

23. The energy absorption device according to claim 15, wherein the second deformation element has a cuboid-shaped or pyramid-shaped design.

24. The energy absorption device according to claim 15, wherein the second deformation element has a strip-shaped design.

25. The energy absorption device according to claim 24, wherein the second deformation element extends over a substantial part of the width extent of the first deformation element.

26. The energy absorption device according to claim 15, wherein the second deformation element is connected to the first deformation element by a form fit, adhesive bonding, and/or by separate connecting elements.

27. The energy absorption device according to claim 15, wherein the first and the second deformation element is produced, respectively, in the form of a multiple-element foam component.

28. A motor vehicle comprising an energy absorption device according to claim 15.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG. 1 shows a schematic illustration of a bumper arrangement with an energy absorption device according to the prior art (left half of FIG. 1) and an energy absorption device according to an embodiment of the invention (right half of FIG. 1).

[0049] FIG. 2 shows a perspective illustration of a first deformation element for a bumper, according to the prior art.

[0050] FIG. 3 shows an illustration, corresponding to FIG. 2, of a first deformation element according to an embodiment of the invention with inserted second deformation elements.

[0051] FIG. 4 shows an enlarged illustration of the detail Z of FIG. 3, with a second deformation element illustrated separately.

[0052] FIG. 5 shows a second exemplary embodiment of the invention in a perspective illustration.

[0053] FIG. 6 shows a perspective sectional illustration in accordance with the sectional profile line VI-VI in FIG. 5.

[0054] FIG. 7 shows a perspective sectional illustration in accordance with the sectional profile line VII-VII in FIG. 5.

[0055] FIG. 8 shows a third exemplary embodiment of the invention in a perspective illustration.

[0056] FIG. 9 shows a perspective sectional illustration in accordance with the sectional profile line IX-IX in FIG. 8.

DETAILED DESCRIPTION OF THE DRAWINGS

[0057] FIG. 1 shows the structure of an energy absorption device according to the prior art compared to an energy absorption device according to an embodiment of the invention.

[0058] A known bumper arrangement, denoted in its entirety by 102, for a motor vehicle has a bumper 104 (bumper crossmember) which runs in the transverse direction of the motor vehicle and is attached to the load-bearing structure of the motor vehicle via a left longitudinal member 106 and a right longitudinal member, which is not illustrated. The bumper 104 is provided with an energy absorption device, which is formed by a first deformation element 108 arranged at the front of the bumper 104. A front edge of a front flap of the motor vehicle is denoted by 105. A cooler 107, among other things, is provided at the rear of the bumper arrangement 102 counter to the direction of travel. The first deformation element 108 has a thickness D of 80 mm, for example. The thickness D may remain approximately the same in the transverse direction of the motor vehicle or may vary in the transverse direction of the motor vehicle.

[0059] The bumper arrangement according to an embodiment of the invention, denoted in its entirety by 2, for a motor vehicle likewise has a bumper 4 (bumper crossmember) which runs in the transverse direction of the motor vehicle and is attached to the load-bearing structure of the motor vehicle via a left longitudinal member, which is not illustrated, and a right longitudinal member 6. An energy absorption device with a first deformation element 8 is arranged on the front side of the bumper 4. One outer and one inner second deformation element 10 are inserted in the first deformation element 8 on each side of the vehicle (only the right side is illustrated). A front edge of the front flap of the motor vehicle is denoted by 5. A cooler 7, among other things, is provided behind the bumper arrangement 2.

[0060] The first deformation element 8 consists of a foam material, preferably a plastics material, for example EPP or PU, for example with a density which is uniform in the transverse, longitudinal and height direction of the motor vehicle of approximately 30 g/l, for example. The second deformation elements 10 likewise consist of a foam material, preferably a plastics material, for example EPP or PU. The density of the second deformation elements 10 is significantly higher than the density of the first deformation element 8 and is approximately 100 g/l, for example. Correspondingly, the stiffness of the second deformation elements 10 is also significantly greater than the stiffness of the first deformation element 8. As a result, the second deformation elements 10 are what are known as “hard foam parts”.

[0061] The foam material of the first and/or the second deformation element is formed by a particle foam, for example, such as EPP. A PUR foam, for example, similarly comes into consideration.

[0062] The first deformation element 8 has a thickness D of 80 mm, for example, in the portions in which no second deformation element 10 is provided. In the regions which have a second deformation element 10, the thickness D1 of the first deformation element 8 is 40 mm, for example. The thickness D2 of the second deformation element 10 is 40 mm, for example. What is to be understood by “thickness” here is the extent in the longitudinal direction of the motor vehicle.

[0063] For example, the second deformation element 10 locally significantly reduces the penetration depth of the object with which a collision occurs during a standardized test procedure (for example a pendulum impact test) by virtue of the local stiffening by the second deformation element 10. The reduced penetration depth makes it possible for the front edge 5 of the front flap of the motor vehicle to be drawn further forward than is the case for a motor vehicle according to the prior art.

[0064] FIG. 2 shows a first deformation element 108 according to the prior art, which is in the form of a foam molding. The outer contour of the first deformation element 108 is matched to the inner side of a bumper cladding, which is not illustrated, resulting in the “jagged” outer contour illustrated in FIG. 2. For example, the deformation element 108 has cutouts 130 for PDC sensors, and a cutout 132 for a towing eye. The rear side, not visible in FIG. 2, of the deformation element 108 is molded in a manner equivalent to the corresponding bumper 104, which is not illustrated, in the sense of a large-area contact surface. A plurality of securing arms 134, by means of which the first deformation element 108 can be arranged in a form-fitting manner on the bumper 104, can also be seen.

[0065] FIG. 3 shows a first deformation element 8 according to an embodiment of the invention, which is identical to the first deformation element 108 according to FIG. 2 except for a right and a left cutout 20 (illustrated in FIG. 4). The cutouts 20 serve according to the invention for accommodating a right and a left second deformation element 10. Moreover, the first deformation element 8 has cutouts 30 and 32, which correspond to the first deformation element 108, and securing arms 34.

[0066] FIG. 4 is an enlarged illustration of the significant difference between the known deformation element 108 and the deformation element 8 according to the invention. The second deformation element 10 is in the form of a hard foam body, for example, which can be clipped into the cutout 20 in the first deformation element 8. The first deformation element 8 is designed as a foam molding, for example.

[0067] FIG. 5 shows a second exemplary embodiment of the invention. The deformation elements 8 and 10 of the exemplary embodiment according to FIG. 5 are matched to the design of a bumper cladding for an equipment variant, for example. Components which are the same and have the same effect are provided with the same reference signs as in the first exemplary embodiment.

[0068] As a departure from the first exemplary embodiment, according to FIG. 5 the right and the left second deformation element 10 have geometrically different configurations. By contrast to the left second deformation element 10, the right second deformation element 10 has on the outside a cutout 22 for a fastening bushing for a towing eye which can be screwed in. In addition, a cutout 24 for a cover for covering the opening for the towing eye is provided on the front side of the right second deformation element 10.

[0069] FIGS. 6 and 7 show the two deformation elements 10 in enlarged sectional illustrations. Here, a channel 26 for accommodating a fluid hose, which is not illustrated, for sensing an impact on the bumper 4 is illustrated on the rear side of the first deformation element 8.

[0070] FIGS. 8 and 9 show an energy absorption device with a first and a second deformation element 8 and 10, respectively. The two deformation elements 8 and 10 extend over a substantial part of the width of a bumper (bumper crossmember), which is not illustrated. In this respect, the first deformation element 8 is designed to make contact with the bumper over its entire surface area. The first deformation element 8 has cutouts 40, into which fastening elements (for example assembly plugs) for attachment to the bumper can be inserted. A channel 26 for accommodating a fluid hose 42 is provided on the rear side, facing the bumper, of the first deformation element 8. The fluid hose 42 serves to sense an impact on the bumper. The adjacent channels 26a and 26b in the first deformation element 8 allow unrestricted deformation of the central channel 26, in order that the fluid hose 42 can optimally deform in the event of a pedestrian impact and thus can sense the impact as best as possible.

[0071] The second deformation element 10 has a strip-shaped form and is arranged in the lower region of the front side of the first deformation element 8, that is to say is arranged upstream of the first deformation element 8. It is connected to the first deformation element 8 by adhesive bonding, for example. In this respect, the second deformation element 10 projects beyond the first deformation element 8 at each lateral end portion. The height of the second deformation element 10 is approximately half the height of the first deformation element 8. The second deformation element 10 has a thickness which is somewhat larger than that of the first deformation element 8. Cutouts 44, 46 and 48 are provided on the front side and/or the top side of the second deformation element 10, for example to pass through a towing eye or to provide a free space for PDC sensors.

[0072] The first deformation element 8 has a density of for example approximately 30 g/l, while the second deformation element 10 has a density of for example 130 g/l.

[0073] The illustration in FIG. 9 is based on a CAD sectional illustration. For clarification purposes, it should be noted that the two deformation elements 8 and 10 are of course solid materials.

[0074] The invention can be summarized as follows: an energy absorption device for a bumper 4 of a motor vehicle has a first deformation element 8 on the front side of the bumper 4. The first deformation element 8 is a foam molding, which reaches over the width of the bumper 4 and has a density of 20 to 50 g/l. At least one second deformation element 10 which has a density which is at least 50 g/l higher than that of the first deformation element is inserted in the first deformation element 8.

LIST OF REFERENCE SIGNS

[0075] 2 Bumper arrangement [0076] 4 Bumper [0077] 5 Front edge of the front flap [0078] 6 Longitudinal member [0079] 7 Cooler [0080] 8 First deformation element [0081] 10 Second deformation element [0082] 20 Cutout [0083] 22 Cutout [0084] 24 Cutout [0085] 26 Channel [0086] 26a Channel [0087] 26b Channel [0088] 30 Cutout [0089] 32 Cutout [0090] 34 Securing arm [0091] 40 Cutout [0092] 42 Pressure hose [0093] 44 Cutout [0094] 46 Cutout [0095] 48 Cutout [0096] 102 Bumper arrangement [0097] 104 Bumper [0098] 105 Front edge of the front flap [0099] 106 Longitudinal member [0100] 107 Cooler [0101] 108 First deformation element [0102] 130 Cutout [0103] 132 Cutout [0104] 134 Securing arm [0105] D Thickness [0106] D1 Thickness [0107] D2 Thickness [0108] Z Detail