Vehicle fenders – Buffer or bumper type – Bumper having impact force absorbing means directly...
Reexamination Certificate
2002-04-19
2003-12-02
Pedder, Dennis H. (Department: 3612)
Vehicle fenders
Buffer or bumper type
Bumper having impact force absorbing means directly...
Reexamination Certificate
active
06655721
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The invention relates to a front end for a motor vehicle having a bumper configuration which has a bumper support and is intended for absorbing impact energy in the event of an impact by another motor vehicle.
Different types of motor vehicles generally have bumper configurations that are disposed at different heights. In the case of accidents in which the front region of a motor vehicle penetrates into another vehicle during the accident, there is often times the effect that, because of the respective support structures of the two motor vehicles, a possible deformation capacity is not used completely and an associated conversion of impact energy does not take place in the components provided for this purpose. As a result, the passenger cell is subjected to a considerable extent to impact energy, so that, when producing the motor vehicle, the passenger compartment has to be configured for relatively large loads in the event of a crash, which requires a corresponding additional outlay.
In order to protect the passenger compartment, European Patent No. EP 0 235 635 B1 proposes a passenger-vehicle chassis which is of a cellular or modular construction. In the case of this chassis, the longitudinal members of the auxiliary frame, that are connected to the front wall for the dimensionally rigid central cell, are provided with predetermined desired bending points. In this case, the predetermined bending points are provided on the longitudinal members in such a manner that after a certain path of deformation of the front end has been exhausted, the deformation of the auxiliary frame along the desired bending points allows to include the drive unit into the deformation, and thus to increase the deformation capacity.
A disadvantage of this configuration is that in the case of an impact of motor vehicles having longitudinal-member planes at respective different heights, the deformation of the components provided for this purpose, for example the longitudinal members and the auxiliary frame, only takes place when the drive unit has been subjected to impact energy. The impact energy is then transmitted to the support structure exclusively via the fastening devices of the drive unit.
Published, Non-Prosecuted German Patent Application No. DE 30 26 749 A1 therefore proposes to provide at least one supporting element on the front end, which element has a stop surface and is assigned to a longitudinal member. The effect achieved thereby is that the impact energy is directed to the components provided for the deformation.
However, a disadvantage of this configuration is that the stop surface is effective exclusively in the vicinity of the longitudinal member and that it has to be ensured that the deformation energy is transmitted during the entire deformation process.
A further disadvantage is that the longitudinal-member plane remains essentially unchanged during the deformation process, and thus in the case of large impact energies, the supporting element can be torn off or deformed and the stop surface can be pushed over or under the longitudinal-member plane of the other party involved in the accident and therefore remains essentially ineffective.
In all of the above-described conventional structures it is disadvantageous that desired predetermined bending points must already be made at the designated points during the production of the motor vehicle. As a result, the rigidity of the components provided with the desired predetermined bending points is reduced and the entire support structure therefore has a reduced rigidity.
SUMMARY OF THE INVENTION
It is accordingly an object of the invention to provide a front end configuration for a motor vehicle which overcomes the above-mentioned disadvantages of the heretofore-known front end configurations of this general type and which in particular ensures that the impact energy of the vehicles involved in an accident is absorbed at an early point by the components provided for the deformation, even in the case of motor vehicles having structurally incompatible chassis.
With the foregoing and other objects in view there is provided, in accordance with the invention, a front end configuration for a motor vehicle, including:
a bumper configuration configured to absorb an impact energy in case of a vehicle impact, the bumper configuration including bumper supports;
lateral longitudinal members having respective longitudinal-member heads connected to respective ones of the bumper supports, the lateral longitudinal members defining a longitudinal-member plane; and
an absorbing device assigned to a given one of the lateral longitudinal members, the absorbing device being configured to absorb at least part of the impact energy outside the longitudinal-member plane, the absorbing device having an active device configured to indirectly transmit at least part of the impact energy to a longitudinal side of the given one of the longitudinal members.
In other words, the object of the invention is achieved in that at least one longitudinal member is assigned at least one absorbing device for absorbing impact energy outside the longitudinal-member plane, and in that the absorbing device is provided with an active device for indirectly transmitting at least some of the impact energy to a longitudinal side of the associated longitudinal member. In this case, it is advantageous for the impact energy to be transmitted in the form of thrust energy via the active device to the longitudinal side of the associated longitudinal member. The thrust energy is converted there into deformation energy. The longitudinal member is therefore pre-damaged at the thrust point of the active device, so that it bends at this point. A further advantageous effect is that the axial rigidity of the longitudinal member can be reduced in this case and therefore differences in the rigidities of the front ends of the motor vehicles involved in the accident can be compensated for without having to reduce the rigidity of the longitudinal member during production with predetermined desired bending points. The effect achieved by the bending of the longitudinal member is that the longitudinal-member planes of the motor vehicles involved in the accident change.
It has been shown that the longitudinal members collapse in each case because of the pre-damage which has been caused. During the bending collapse caused in this manner impact energy is converted into deformation energy on both sides of the parties involved in the accident. It has also turned out that the configuration according to the invention has a favorable effect on the structural behavior of the longitudinal members by dispersing or dissipating the absorbed energy during the bending collapse. The great rigidity of the longitudinal members means that the deformation modes of the folding and buckling remain unaffected during a frontal impact with a rigid obstacle, since in this case the active device is displaced parallel together with the folding unit in the direction of the center line of the longitudinal members because the absorbing device is not deformed. This is assisted particularly by the fact that desired predetermined bending points for changing the longitudinal-member plane during the crash can be omitted.
Moreover, in the case of relatively large vehicles, the rigidity of the front end is reduced by the pre-damage or preliminary damage to the longitudinal-member head, which, in the case of collisions of two vehicles having respective different rigidities of the chassis, results in a more favorable deformation behavior for the weaker party in the accident. On the other hand, in the case of accidents not involving other parties, the undiminished energy-absorbing capacity is available during the folding and buckling process as a result of the manufactured rigidity.
The configuration according to the invention can moreover be realized in an advantageous manner by using a simple structural construction.
According to another feature of the invention, the absorbing device is connect
Beck Manfred
Pedder Dennis H.
Volkswagen AG
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