Land vehicles – Wheeled – Attachment
Reexamination Certificate
1999-10-04
2001-07-24
Rice, Kenneth R. (Department: 2167)
Land vehicles
Wheeled
Attachment
Reexamination Certificate
active
06264235
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates generally to a steering wheel having a hub, spokes, a steering wheel rim, and an airbag module.
Steering wheels of motor vehicles are generally fitted with an airbag for the protection of the occupant in the event of a crash. The airbag is thereby mounted rigid or movable in an airbag module in the center of the steering wheel relative to the longitudinal axis of the steering column. This driver airbag has a symmetrical shape in the inflated state so that it is active in the same way irrespective of the rotary position of the steering wheel.
The drawback with the known driver airbag is that the symmetrical shape does not offer optimum protection for the occupant. An asymmetric shape could indeed improve the protection when the steering wheel is in a certain position, e.g. when set up straight. In other positions of the steering wheel, an asymmetrical position would impair protection compared with a symmetrical airbag.
A further drawback is that the airbag unfolds inclined upwards in the event of a crash depending on the angle of the steering column. The airbag thereby does not act with its entire surface area evenly on the body of the occupant but certain areas of the body suffer greater impact. To avoid this disadvantage it is known from DE 196 07 193 A1 to tilt the steering wheel downwards. The steering wheel is thereby fixed for articulated movement in the upper area of the hub and in the event of a crash can be turned away downwards through a pyrotechnic device. The plane of the steering wheel rim is thereby set approximately parallel to the body of the occupant. The airbag then unfolds in a direction which is approximately the horizontal direction and the airbag forces act more uniformly on the driver. At the same time the risk of injury through the lower area of the steering wheel rim is also reduced.
The drawback with this tilting steering wheel is that a pyrotechnic device with associated electronics is required to tilt the steering wheel in the event of a crash.
The object of the invention is to change the steering wheel so that improved protection of the occupant is possible independently of the position of the steering wheel and without the expense of extra measures.
SUMMARY OF THE INVENTION
With a steering wheel having a hub, spokes, a steering wheel rim and an airbag module, according to the present invention a rotary mounted component part for holding at least a further subassembly is fixed on the steering wheel hub or in the associated steering column. The center of gravity of the component part and/or the additional subassembly lies eccentric so that during rotation of the steering wheel the rotary mounted component part remains in the same position that it occupies when the steering wheel is straight. The rotary axis of the rotary mounted component part preferably coincides with the longitudinal axis of the steering column holding the steering wheel. The center of gravity of the rotatable component part therefore lies underneath the upwardly inclined longitudinal axis and also remains there during rotation of the steering wheel.
This steering wheel according to the present invention contains a sub-assembly which does not rotate with the steering wheel. Thus new possibilities are disclosed for increasing the safety of the driver in the event of a crash.
In a first embodiment, a weight with a circular base surface is mounted on the rotatably mounted component part and its center of gravity lies outside of the rotary axis. This position of the center of gravity can be achieved, for example, by an outwardly extending expansion on one side of the weight or by a section of smaller diameter. The weight can, however, have any other shape wherein the center of gravity lies outside of the rotary axis of the rotatable component part.
In order to be able to connect subassemblies to the rotary mounted component part for increasing the safety of the driver in the event of a crash [to the rotary mounted component part], it is expedient if the rotary mounted component part and the weight are plate-shaped.
One possibility of using the rotary mounted component part for increasing the safety of the passenger is if a deformation element is provided on and fixed to the rotary mounted component part. The deformation element lies above the rotary axis and extends in the direction of the steering wheel rim. In the event of a crash, the deformation element can be deformed preferably away from the driver by a component part of the steering wheel. This deformation element always remains above the longitudinal axis during rotation of the steering wheel. It has now surprisingly been found that in the event of a crash, a relatively slight deformation of the deformation element caused by the driver, and a slight bending of the steering wheel above the longitudinal axis of the steering column with corresponding dimensioning of the spokes leads to a sharp bending of the steering wheel underneath the longitudinal axis. The plane of the steering wheel rim thereby no longer runs inclined relative to the driver but runs at least approximately parallel to the body. The airbag is thereby positioned during the load phase practically parallel to the thorax of the driver so that the thorax is also stressed simultaneously by the entire front surface of the airbag. The specific surface load stress, and thus the risk of injury to the driver through the airbag, is thus lower. The biomechanically correct positioning of the airbag is guaranteed in all cases and the airbag cannot be, at any point in time, pushed away from the driver. A further advantage is that energy is absorbed by the deforming steering wheel as well as by the airbag.
A further possibility for improving the protection of the driver is where an intermediate ring is provided on the steering wheel and is connected on one side by hub spokes to the steering wheel hub and on the other side by rim spokes to the steering wheel rim, whereby at least the hub spokes are deformable in the event of a crash. This division into hub spokes and rim spokes makes it possible to mount the hub and rim spokes at different places. In one embodiment, four symmetrically arranged hub spokes are provided having the same angular spacing from each other, and four symmetrically arranged rim spokes are provided. In the plan view of the steering wheel, and with the steering wheel in the straight position, the two lower rim spokes have at least approximately the same path as the hub spokes, and the other two rim spokes, that run in the upper steering wheel area, are flatter than the hub spokes.
The arrangement of the spokes at the same angular spacing is generally for reasons of strength and stability. Owing to the requisite view of the instruments on the instrument panel, such an arrangement is, however, not practical. However, by dividing the spokes into two, the same angular spacing is now possible in the hub part.
In a further embodiment, the intermediate ring and the deformation element are combined with each other. Thus it is proposed that the end of the deformation element that points towards the steering wheel rim is associated with the intermediate ring, whereby the deformation element and the intermediate ring are in engagement with each other without contact. The end of the deformation element pointing towards the steering wheel rim preferably has the shape of a fork into which an edge of the intermediate ring engages.
The intermediate ring and the deformation element do not normally contact one another, i.e. during rotation of the steering wheel, the rotary mounted component part remains in the same position which it occupies when the steering wheel is straight. Only in the event of a crash is the intermediate ring pressed against the deformation part resulting in the deformation of the deformation part.
It is expedient if the hub spokes extend between the steering wheel hub and the intermediate ring in the form of an L-shaped angle.
In a further embodiment of the invention, it is proposed that the a
Adomeit Heinz-Dieter
Battermann Jens
Kamm Martin
Reh Stefan
Samarae Sami Al
Foley & Lardner
Petri AG
Rice Kenneth R.
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