Land vehicles – Wheeled – Attachment
Reexamination Certificate
1998-04-14
2001-02-20
Mai, Lanna (Department: 3619)
Land vehicles
Wheeled
Attachment
C188S377000, C074S492000, C280S777000
Reexamination Certificate
active
06189919
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a steering column arrangement for vehicles as well as occupant protection arrangements, safety steering features, and steering wheels using such steering column arrangements. The invention also relates to methods of producing steering column arrangements.
Steering column arrangements in vehicle construction are generally known and have numerous modifications. Such steering column arrangements are usually provided with a deformable structure so that in a frontal impact the steering column and steering wheel will not be moved toward an occupant. The deformations which occur in the front of the car during a frontal impact thus positively assure that the spacings between a first connection of the steering column with the steering wheel and between a second connection of the steering column with the steering mechanism will be compressed. Merely by way of example, reference is made in this context to U.S. Pat. No. 5,169,172. For occupant protection in vehicles, it is also known that steering columns of the type described above may be coupled to steering mechanisms by energy absorbing elements so that in event of an impact by the occupant on the steering apparatus during an accident, the risk of injury may be very much reduced. A typical arrangement is disclosed in German Offenlegungsschrift No. 195 08 443 A1.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a steering column arrangement for vehicle occupant protection which overcomes disadvantages of the prior art.
Another object of the invention is to provide a steering column arrangement by which the risk of injury to vehicle occupants may be further reduced.
These and other objects of the invention are attained by providing a uni- or multi-part steering column having connections which include at least one associated deformation member. Such deformation members are constructed to be deformed in response to an application of force having a magnitude to be expected in an accident so that they make possible a compression of the steering column which is required for reasons of safety either alone or supplementary to conventional compression arrangements. As a further important feature, an intermediate steering column segment of essentially stable shape is provided between two or more such deformation members . In this context, “stable shape” means that, under the loads to be expected during a vehicle accident, no significant deformations occur. The change in length of this segment of the steering column when acted upon by compressive forces during a collision are so slight that they amount to, for example, at most 5% of the total compression of the steering column arrangement.
The spaced arrangement of deformation members with inclusion of an intermediate segment of essentially stable shape provides numerous advantages. The steering column itself contributes to energy absorption and thus ensures a relatively gentle contact of a vehicle occupant with the steering column arrangement as the impact force approaches the force response threshold of a steering column bearing in which the steering column is rotatably supported on the vehicle structure. Furthermore, the deformation members provide an articulation function. Thus, for example, the deformation member between the stable segment of the steering column and the steering mechanism can diminish the tilting motion of the entire steering column which normally occurs in front end collisions so that there is hardly any upward motion of the steering wheel. Supplementarily or alternatively, articulated motion of the deformation element between the stable segment of the steering column and the steering wheel makes it possible that, especially in the case of an exceptionally large or small occupant, an energy absorbing displacement of the steering wheel can take place even though it is oriented at an unfavorable angle with respect to the occupant. In this connection, it should be noted that some of the energy absorption capacity normally provided by the steering wheel itself can be transferred to the adjacent deformation element. Accordingly, the steering wheel itself need not be a three- or four-spoke steering wheel, but may be a two-spoke wheel instead. This permits additional lightweight construction potentials for a steering system which includes a steering column arrangement according to the invention.
Another important advantage of the invention is that, with a steering column of tubular construction, parts of an airbag arrangement may be mounted directly within the steering column. In other words, the steering column also serves as the housing for at least one gas generator with a diffuser and associated airbag. Likewise possible is a subdivided airbag arrangement in which only the gas generators, for example, are mounted inside the steering column, while the airbag to be filled by the gas generators is stowed inside the hub of the steering wheel. Snap fastenings such as are described, for example, in the published International Application No. WO 97/01460 may be used for attachment of the steering wheel to the steering column. In contrast to the embodiments disclosed therein, however, the gas generator in a preferred embodiment of the invention is not mounted in the steering wheel hub, but instead is mounted in the intermediate segment of the steering column. This arrangement also provides potential for lightweight construction, for example, by making the gas generator housing an integral component of a cylindrical jacket constituting the intermediate segment of the steering column in accordance with the invention. In other words, the inner wall of the intermediate segment of the steering column is at the same time a housing wall for one or more gas generators. The outer wall of the intermediate segment, by contrast, provides a seat for rotary bearing members in a steering column support.
The invention also permits the use of ring fuses for propellant charges accommodated in the gas generators which may be activated regardless of the angular position of the steering wheel. The winding lines normally extending around the steering column in conventional steering systems for connecting the gas generator to a control unit, i.e., the so-called winding springs, may thus be omitted entirely. Conventional ring fuses such as are known, for example, in ordnance technology may be used. The ring fuses may either be arranged on the outside of the intermediate segment of the steering column or be integrated in its walls. Ignition energy may be introduced into the propellant charge of the ring fuses by a mechanically and/or electromagnetically operated trigger.
To provide a simplified assembly and to reduce the total number of parts, it is preferable to fabricate the tubular member as a hydroformed and/or internal high-pressure transformed part. With such fabrication, all connections, for example adapter segments for coupling a steering column base to the steering mechanism or for the steering mechanism itself, are molded directly onto the steering column.
In addition, such moldings can form an arrest notch or cam in which, for example, a bolt actuatable by a steering wheel lock can be received to lock the steering column.
Alternatively, the tubular member may be produced by rolling. In a preferred method of production, first a subassembly consisting, for example, of gas generator and a diffuser, is mounted within a semi-fabricated tube. Then, by rolling deformation, an energy-absorbing bellows or corrugated deformation section is rolled on at each of the two free ends of the tube so that the subassembly is fixed in place in the tube at the same time. The assembly thus produced may be enlarged by adding at least one airbag or may be combined with a steering wheel in which an airbag is mounted.
Especially important is the arrangement of at least one of the deformation elements as a damper to control the expansion velocity of the airbag. For this purpose, folds of the airbag may be laid with precision in tro
Sinnhuber Ruprecht
Wohllebe Thomas
Baker & Botts L.L.P.
Jasmin Lynda
Mai Lanna
Volkswagen AG
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