Vehicle fenders – Buffer or bumper type – Bumper having impact force absorbing means directly...
Reexamination Certificate
2000-06-07
2001-05-08
Gordon, Stephen T. (Department: 3612)
Vehicle fenders
Buffer or bumper type
Bumper having impact force absorbing means directly...
C293S134000, C293S135000, C293S107000
Reexamination Certificate
active
06227583
ABSTRACT:
BACKGROUND OF THE INVENTION
Field Of The Invention:
The invention relates to an impact energy absorption device for a motor vehicle wherein a cylinder drives a bumper longitudinally forwardly just prior to collision impact.
Description Of Prior Developments
For absorbing the impact energy in the event of a collision at a low vehicle speed, motor vehicles have fenders or bumper bars with baffle elements which absorb so much impact energy that damage to other components of the vehicle, such as, for example, the lighting system, body and side members, is avoided. The amount of absorbable energy depends on the permissible deformation travel and the resistance force of the fender system. The force level selected for its baffle elements must be so low that the vehicle components carrying the baffle elements are prevented from being compressed in the event of a deformation of the latter.
Since the required deformation travel is required only in the event of a motor vehicle collision and, in the normal driving mode, a corresponding front structure on a motor vehicle constitutes an undesirable lengthening of the latter, it is appropriate to equip a vehicle with extendable baffle elements which, by known sensor technology which detects an obstacle in enough time before the collision, are activated in such a way that they are extended immediately before a collision of the motor vehicle.
DE 196 54 559 discloses an impact absorption device of this type for a motor vehicle, with a component which absorbs impact energy and which is capable of being extended in the longitudinal direction of the motor vehicle out of an initial position, in which it is received essentially in a vehicle side member, into a collision position. When an accident is imminent, the component absorbing impact energy is automatically driven into its collision position in which it projects from the vehicle and in which the full impact energy absorption capacity is available. For this purpose, the component absorbing impact energy is designed with a cylinder arranged in the vehicle side member and with a piston which constitutes a deformable reducing tube and which can be moved into the collision position by means of compressed gas. In the event of a collision, the impact energy is transmitted from a fender or baffle elements to the reducing tube, the latter being pressed through a reducing ring in the longitudinal direction of the side member.
In terms of efficiency, however, this known solution with a reducing ring is not satisfactory in the case of a relatively high collision speed and in view of the high outlay in the manufacture of the reducing ring. Furthermore, the disadvantage of this solution is that, even with the reducing ring pushed in, the cylinder, together with the reducing ring arranged in it, projects beyond the side member in the region of the reducing ring, so that the side member is lengthened by the amount of a fixed block which reduces the free deformation length up to the side member.
EP 0 857 619 A1 discloses a further energy absorption device with an extendable element which is capable of being extended out of a side member and which at its front end has a crossmember as a baffle element which is deformed in the event of a collision. In this solution, too, the impact energy absorption achieved by the deformation of a hollow profile on the extendable element is insufficient, and there is also no guidance for the axial deformation movement, so that the extendable element absorbs force unevenly.
DE 296 06 069 U1 describes a further impact energy absorption device with an impact absorber which is capable of being driven out of a cylinder and which has a telescopic design and is pushed together in the event of a collision.
In addition to these known solutions aimed at offering as long a deformation travel as possible by means of displaceable extendable elements, numerous turn-up tube energy absorption elements are known which operate under the principle of rolling bending and allow high energy absorption with a uniform force level.
DE 42 41 103 discloses such an energy absorption element in the form of an impact damper which has a turn-up tube capable of being overturned outwards, the turn-up tube being supported on a suitable turn-up tool for the purpose of being turned over at the associated end. Furthermore, the turn-up tube encloses a fluid-filled pressure chamber with a throttling outflow.
DE C 11 72 558 describes an impact damping device in which an overturnable sleeve made of deformable metal is arranged between two cylindrical parts of different diameter which are displaceable relative to one another and one within the other, the sleeve being firmly attached with one end-face region to one cylindrical part and with the other end-face region to the other cylindrical part.
DE 41 34 545 C2 discloses a mechanical energy absorption element with two profiles which are displaceable one within the other and to which is fastened a material strip made of flexurally soft and tear-resistant material and deformable during the displacement of the profiles as a result of forces acting on it, the fastening to at least one of the two profiles taking place in a sheet-like manner and the essential contribution to energy absorption being that this sheet-like fastening comes loose successively during the displacement of the profiles.
However, all these known solutions require a front-structure length which is necessary, depending on the desired amount of energy absorption.
A combination of an extendable deformation element and the operative principle of rolling bending is described in DE 198 03 156, in which, in a normal position of rest, a turn-up profile is held in a deformation position, out of which the turn-up profile can be transferred abruptly into an absorption position when a drive device is activated. Under an impact load, the turn-up profile is turned back into its deformation position again. However, along with multiple rolling bending and the additional absorption of impact energy, the material of this known turn-up profile is exposed to very high loads.
SUMMARY OF THE INVENTION
The object of the present invention is to provide an impact energy absorption device for a motor vehicle by means of which as small a front-structure length as possible can be implemented in the state of rest, and by means of which, in the event of a vehicle collision, high energy absorption, with a uniform force level, is to be achieved, while at the same time the formation of a block during deformation is largely avoided.
The impact energy absorption device according to the invention has the advantage that, in the normal driving mode, with the extendable element retracted in the side members, it has a small overall size and is positioned in the vehicle in a visually inconspicuous way. Since the extendable element can be moved abruptly into its working position and can be detained in this position by a trigger, a front structure with a deformation travel for a vehicle collision is nevertheless available in enough time, as required. During the displacement of the structural body, consisting of a cylinder and an extendable element, as a result of an impact load, the turn-up profile arrangement can absorb very high energy by rolling, the components which are displaced axially being guided axially during the deformation. This, in turn, brings about advantageous uniform force absorption.
It is also advantageous, in the impact energy absorption device according to the invention, that, in the case of a corresponding rolling length of the turn-up profile arrangement, the extendable element and the cylinder can be pushed into the side member to an extent such that, in the event of a subsequent deformation of the vehicle side member, these components do not contribute to a formation of a block which would shorten the deformation length of the vehicle side member.
In the impact energy absorption device according to the invention, the efficiency of the impact energy absorption can be set optimally by a variation in the diameters and wall
Eipper Konrad
Scheffzük Matthias
Coletta Lori L.
Daimler-Chrysler AG
Gordon Stephen T.
Shurupoff Lawrence J.
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