Patent ID: 12252088

FIGS.1to4illustrate a vehicle occupant restraint system10which in this case is designed for a vehicle occupant12seated in a front seat14. In a roof area16of the vehicle, an airbag module18assigned to the respective front seat14is disposed. Therefore, the airbag module18is located, relating to both a vehicle longitudinal direction L and a vehicle transverse direction Q, above the front seat14, in this case approximately above the thighs of the vehicle occupant12(indicated inFIG.1, for example).

The airbag module18includes an airbag20shown in a completely filled state inFIGS.1,3and4.

The airbag20comprises a body22which accounts for a major part of the filled volume of the airbag20and on which a baffle24facing the vehicle occupant12is formed. On the side opposed to the baffle24, the body22of the airbag20includes a rear side26. The contour of the baffle24and the rear side26defines a longitudinal axis I of the airbag20extending from a lower end28to an upper end30. In this example, the lower end28is also marked by the point where the baffle24and the rear side26are connected to each other.

At the upper end30, the body22of the airbag20merges into a narrow neck32that connects the body22to an inflator34of the airbag module18(indicated inFIG.1, see alsoFIGS.30to35). The neck32has a considerably smaller filling volume than the body22and is formed to be narrower than the body22both in the vehicle longitudinal direction L and in the vehicle transverse direction Q.

Whereas the body22provides the volume required for absorbing the vehicle occupant12, the neck32serves for connecting the body22to the airbag module18and for positioning the airbag20at the desired location in the vehicle interior.

In this example, in the vehicle a sensor system36is provided comprising a controller not shown in detail as well as various sensors which can detect, for example, a position of the front seat14, a position of the vehicle occupant12and/or a current driving situation of the vehicle.

In this example, the vehicle includes a steering wheel38assigned to the front seat14so that the vehicle occupant12can grip it to manually steer the vehicle.

Moreover, in this example in the steering wheel38its own steering wheel airbag40that can be filled in a situation of restraint to absorb the vehicle occupant12is disposed.

The sensor system36here also comprises a sensor that detects whether or not the vehicle occupant12is touching the steering wheel38, which reveals whether or not the hands of the vehicle occupant12are positioned on the steering wheel38.

This is usually the case when the vehicle is moving and the vehicle occupant12manually steers the vehicle. In a driving situation in which the vehicle drives fully autonomously or semi-autonomously, the vehicle may happen to travel in the traffic, but the vehicle occupant12is not manually steering the vehicle and therefore is not keeping his/her hands on the steering wheel38for quite some time.

In a possible method for operating the vehicle occupant restraint system this detection is utilized to decide in a situation of restraint whether or not the airbag is to be filled.

If it is detected that the vehicle occupant12is not touching the steering wheel38, possibly for a predetermined period of time, then exclusively the airbag20but not the steering wheel airbag40is filled. This situation is illustrated inFIG.1.

If it is detected, however, that the vehicle occupant12is gripping the steering wheel38, then exclusively the steering wheel airbag40but not the airbag20is filled (seeFIG.2).

It is optionally possible, in a driving situation in which the vehicle occupant12is largely spaced from the steering wheel38, for example, because the front seat14is run far back, to fill both the airbag20and the steering wheel airbag40, as sketched inFIG.3.

FIG.4illustrates a driving situation in which the steering wheel38is immersed behind a lining42in a fully autonomous or semi-autonomous driving situation and, thus, in a situation of restraint the steering wheel airbag40is not available, either. If in this driving situation a situation of restraint occurs, then exclusively the airbag20will be filled, of course.

The same situation is given, as a matter of course, when the steering wheel38does not include its own steering wheel airbag40. Then basically the airbag20is filled in the situation of restraint.

Alternatively,FIG.4shows a front seat14to which no steering wheel is assigned, for example a passenger seat, wherein in such case the lining42is formed by an instrument panel.

In one example, identical airbag modules18in the roof area16are assigned to all front seats14of the vehicle. It is also possible, of course, to provide airbag modules18for other vehicle seats such as in the rear area or in coaches.

FIGS.5to7illustrate the sequence of a situation of restraint. It is visible that the airbag20deploys from the roof area16substantially perpendicularly downwards (Z-direction) between the vehicle occupant12and the steering wheel38, the baffle24being placed in front of a head44and an upper torso46of the vehicle occupant12. As illustrated inFIG.6, the airbag20reaches this position before the vehicle occupant12immerses into the airbag20. The airbag20absorbs the head44and the upper torso46of the vehicle occupant12by the baffle24, as is evident fromFIG.7.

FIGS.8and9once again illustrate the vehicle occupant12being absorbed in a situation of restraint.

Also, it is visible in said Figures that inside the airbag20two tethers48,50are provided each of which acts by one end with an attachment point52on the baffle24. In this example, the tethers48,50extend approximately in parallel to each other and approximately horizontally, and each tether is connected to the rear side26by an attachment point53opposed to the attachment point52.

The tethers48,50restrict an expansion of the filled airbag20along the vehicle longitudinal direction L.

It would also be possible to use only one tether or more than two tethers.

All tethers48,50in this case are configured so that, throughout the entire situation of restraint, they remain tightly connected to the baffle24and the rear side26and also remain intact in themselves and maintain the same length.

The attachment points52on the baffle24are disposed here above and below an area of the baffle24on which the head44of the vehicle occupant12impacts.

FIGS.10to25illustrate the cut of the surface area of the airbag20, more exactly of the body22, in detail for different shapes of the filled airbag20.

In general, a large variation of shapes for the filled body22can be obtained by the shape of the individual cut parts.

The principle of shaping is based on the fact that outer edge portions of different cut parts of equal length are connected to each other so that together they result in an arched surface having a larger surface area than the resulting peripheral edge. Since the respective outer edge portions have equal lengths, they can be connected without any gatherings or darts being required.

The length and the contour of the outer edge portions decide on the shape. However, it is not important whether the individual cut parts are completely separate pieces of fabric or whether they are integrally connected in places to each other at portions which, in the case of separate cut parts, would be connected by a straightly extending connection.

All cuts shown here follow this basic principle.

The rear side26of each body22of the airbag20is formed of one single cut part54, whereas the baffle24is made from one or more cut parts.

FIGS.10to12illustrate a first example.

The cut part54is connected to an adjacent cut part56of the baffle54at the lower end28of the body22. The two cut parts54,56may be formed integrally or may initially be separated from each other.

The baffle24is composed, in this example, of the cut part56and another cut part60that is adjacent to the cut part56on the opposite side of the cut part54. The cut parts54,56,60are lined up along the later longitudinal axis I of the body22.

In the finished airbag20, adjacent outer edge portions58of the two cut parts54,56,60are connected to each other in a known manner (e.g., by sewing, gluing or welding) and together form a peripheral connection at which the baffle24and the rear side26adjoin each other, as illustrated inFIG.10.

The two cut parts56,60forming the baffle24are moreover interconnected at outer edge portions62. This imparts a per se three-dimensional shape to the baffle24so that the baffle24cannot be completely flatly spread.

The outer edge portions58,62to be interconnected are of equal length but may have different contours.

Each of the cut parts54,56,60is mirror-symmetrical in this case with respect to the longitudinal axis I.

FIGS.13to15illustrate a shape of the body22of the airbag20in which the baffle24along the vehicle longitudinal direction L (in the mounted and filled state) includes a bulge66that extends toward the vehicle occupant12and allows him/her to contact the airbag20at an early stage (see alsoFIGS.1,3and4, for example).

The bulge66is located in the area of the baffle24that is provided for absorbing the head44of the vehicle occupant12, and lies in an upper area of the baffle24(seeFIG.15, for example). As is illustrated inFIG.13, the bulge66extends beyond the remaining baffle24by an amount Ax.

The tethers48,50equally provided in this example act on the baffle24with each of their attachment points52above and below the bulge66.

The bulge66is produced by the baffle24being composed of a total of three cut parts56,68,70, as is shown inFIG.14. The cut part56is, just as in the embodiment ofFIGS.10to12, approximately semicircular, but, in this case, is a separate part and is connected to the cut part54by a further connection.

The two cut parts68,70are arranged mirror-symmetrically and next to each other (based on the vehicle transverse direction Q and the longitudinal axis I). Each of them includes a laterally projecting area72, the two areas72facing each other and being connected to each other at their outer edge portions74. In the filled airbag20, the connected outer edge portions74are located, based on the vehicle transverse direction Q, in the center of the baffle24.

As is evident fromFIG.13, the outer edge portions58of the cut parts56,68,70facing the cut part56are connected to the cut part54.

FIGS.16and17illustrate a second cutting shape by which a bulge66can be obtained. The difference from the variant shown inFIGS.13to15merely resides in the shape of the cut parts68,70.

FIGS.18and19illustrate a variant the shape of which is similar to the airbag20ofFIGS.10to13.

In contrast to that, however, two tethers48,50are disposed inside the airbag20, the tethers being combined approximately level with the longitudinal axis I and from there leading, by one single tether portion, to one single attachment point53on the rear side26. Thus, a Y-shaped tether is resulting whose arms end, corresponding to the tethers48,50, at respective attachment points52on the baffle24. The lower tether50extends obliquely upward toward the upper end30of the body22of the airbag20and so-to-speak forms a stem of the Y. The attachment point53thereof is located at the upper end of the rear side26, in the vicinity of the attachment of the neck32, in this case.

FIGS.20to25illustrate variants of the airbag20in which even the baffle24is made of one single cut part56only. Here the three-dimensional shape is obtained by the differently formed contours of the outer edge portions58of the cut parts54,56.

Furthermore, in this example only the respective upper tether48is provided.

InFIGS.26and27, an optional airbag retraction mechanism76is illustrated which is configured to retract the lower end28of the airbag20upward in the direction of the roof area16and away from the field of view of the vehicle occupant12, after the airbag20has fulfilled its protecting function.

During and after immersion of the vehicle occupant12into the body22of the airbag20(seeFIG.26), the filling gas escapes from the airbag20through vents (not shown) so that the airbag20becomes compressible again.

A retracting tether78acting on the lower end28of the airbag20is connected to the airbag retraction mechanism76disposed in the roof area16so that, when the length of the retracting tether78is reduced inside the airbag, the lower end28of the airbag20is lifted upward in the direction of the roof area16. In this way, the airbag20is withdrawn from the area of view of the vehicle occupant12.

The retracting tether78can extend inside the airbag20or along the outer side of the airbag20, e.g., along the rear side26.

It is also possible to connect or combine the retracting tether78with one or more of the shaping tethers48,50acting on the baffle24inside the airbag20. For example, the Y-shaped tether48,50shown inFIG.22could be connected with the retracting tether78.

The airbag retraction mechanism76may be integrated in the airbag module18, for example. A suitable pyrotechnical or mechanical drive (not shown) is used to withdraw and, e.g., gather or furl the retracting tether78.

The airbag retraction mechanism76is actuated as soon as the actual situation of restraint is terminated so that the vehicle occupant12regains visibility through the windscreen80of the vehicle as soon as possible.

InFIGS.28and29, an optimum steering wheel positioning mechanism82is illustrated that is configured to move the steering wheel38away from the vehicle occupant12before or during a situation of restraint. This helps increase the space for the vehicle occupant12, especially for his/her legs.

FIG.28illustrates a solution in which the steering wheel38is displaced linearly along the direction of a steering column toward the vehicle front end.

FIG.29illustrates a solution in which the steering wheel38is pivoted upward or downward about an angle of approx. 30° to 90°.

In both cases, the drive may be pyrotechnical or mechanical, for example.

If such steering wheel positioning mechanism82is provided, no steering wheel airbag40is disposed inside the steering wheel38, and the airbag20is used as the sole frontal airbag.

InFIGS.30to32, the structure of the airbag module18is shown in greater detail.

A module housing84is tightly fixed to a roof cross-member88via mounting tabs86and corresponding screws. In the module housing84, which is made, for example, from sheet steel or any other suitable rigid material, the inflator34as well as the airbag20folded into a package89are accommodated. The inflator34protrudes into the airbag34with a gas outlet area90.

Via the module housing84, the inflator34and the airbag20are also fixed tightly and permanently to the roof area16.

A lining such as a roof liner92covers the airbag module18from the interior of the vehicle.

The airbag module18is disposed in the area of a sun visor94so that the airbag20deploys between the windscreen80and the sun visor94.

The inflator34is disposed in parallel to the vehicle transverse direction Q.

InFIGS.33to35, an option for connecting the inflator34to the airbag20is illustrated. The end of the neck32that does not lead into the body22of the airbag ends in an opening96adapted to the diameter of the inflator34into which the gas outlet area90of the inflator34is inserted (seeFIG.34). Here, a rim of the opening96is turned over to the outside so that a defined insertion opening is resulting.

After inserting the inflator34, the same is fixed to the airbag20via one or more suitable clamps98which are slipped over the inflator34and the rim of the opening96.

The gas outlet area90is arranged, in this way, centrally in the neck32so that upon activation of the inflator34the filling gas flows directly through the neck32into the body22of the airbag20.