Patent Application
20160082918
The invention relates to an airbag for a motor vehicle, comprising a gas cushion which is formed from at least two layers of fabric and which is brought on inflation from a folded or rolled state into an unfolded state, the at least two layers of fabric being connected to each other at connection points to form inflated cushion portions and non-inflated cushion portions, and the connection points having linear connection points and rounded connection points.
Such an airbag for a motor vehicle is known, for example, from EP 1462321 B1 or EP 1228930 B1.
Using such airbags for lateral impact protection device is known from the prior art. The gas cushion is disposed in the rolled-up or folded state in the roof edge area. When the gas cushion is inflated, it unfolds itself and extends from the roof edge area between the side panes and surrounding side frame portions of the vehicle body and the position of a vehicle passenger or the positions of two or more vehicle passengers seated one behind the other. In rollover situations, in particular, it is essential that the inflating pressure in the inflated cushion portions be maintained for a certain duration to ensure that the required safety function is provided, in particular the required impact protection against the side parts of the vehicle.
The object of the invention is therefore to improve, at no additional expense, the tear strength of the connection points defining the inflated and the non-inflated cushion portions, in order to ensure that the inflating pressure is maintained for the required duration.
This object is achieved by an airbag having the features specified in claim.
The dependent claims contain advantageous developments of the invention.
In the invention, the linearly extending connection points are arranged at an angle of 45° relative to the threads forming the layers of fabric, which may be present in the form of warp threads and weft threads. However, the linearly extending connection points may be arranged at an angle which deviates slightly from the aforementioned angle and which does not impair the tear strength of the connection points when the gas cushion is in the inflated state. This slight deviation in angle may be ±10°.
Linear connection points running at right angles to each other may preferably be connected to each other by rounded connection points.
Self-enclosed connection points with a square or rectangular shape and with rounded corners are preferably used to form the inflated or non-inflated cushion portions.
When the cushion portions are of different sizes, the radii of the connection points provided at the rounded corners are proportional to the lengths of the respective linearly extending connection points of the cushion portions or proportional to the dimensions of the cushion portions.
The at least two layers of fabric in the gas cushion may be of the OPW (one-piece-woven) type or may be made from two or more sections of fabric.
In the case of an OPW-type gas cushion, the connections between the layers of fabric are formed by joining the warp and weft threads in the two layers of fabric made from a single piece of fabric.
In gas cushions made of two or more sections of fabric, the connections are formed as the tuck joining the layers of fabric.
The gas cushion is preferably formed in such a way that it can be disposed in the folded state between an inner side region of the motor vehicle, and a passenger position or a plurality of passenger positions arranged one behind the other. To that end, the gas cushion can be disposed in the folded or rolled-up state in the roof edge area and on inflation can be unfolded downwards towards the vehicle floor.
An embodiment of the invention shall now be described in more detail with reference to the Figures, in which
The gas cushions may be of the OPW type, or may be formed of several sections, for example two sections. Fixing means 11 with which the gas cushion can be fixed to the vehicle body, in particular in the roof edge area, are provided at the upper edge of gas cushion.
In the embodiment shown, the non-inflatable cushion portions 4 are enclosed by linearly extending connection points 5 and rounded connection points 6. These connection points separate the non-inflatable cushion portions 4 from inflatable cushion portion 3. In the embodiment shown, the non-inflatable cushion portions 4 are square or rectangular in shape with rounded corners 2.
The embodiment shown in
The linear connection points 5 and the rounded connection points 6 may also enclose inflatable cushion portions 3 and demarcate them from a non-inflatable cushion portion, for example a cushion portion 9. In that regard, it is possible to supply a filling gas, for example with the aid of a gas conduit 2 which connects the other inflatable cushion portions 3 to the inflatable cushion portion 3 enclosed by connection points 5 and 6.
The linear connection points 5 and the rounded connection points 6 are thus embodied in such a way that they separate the non-inflatable cushion portions 4 from inflatable cushion portions 3. In order to ensure that the inflation gas remains in the inflatable cushion portions 3 for a sufficient duration of time in the event of an accident, for example a rollover situation, it is necessary that connection points 5 and 6, which are provided between the non-inflatable and inflatable cushion portions, withstand the inflation pressure and do not rip open.
To ensure this, the linear connection points 5 extend at an angle of 45°, for example, relative to the longitudinal extensions of threads 7 and 8 (warp and weft threads) from which the layers of fabric forming gas cushion 1 are woven. Measurements have shown that, when filling pressure has been built up in gas cushion, the forces acting on linear connection points 5, which are arranged at an angle of approximately 45° relative to the threads of fabric 7, 8, are smaller than the forces acting on connection points which are arranged parallel and perpendicular, for example, to threads 7, 8. The forces involved differ by a factor of about 1.7.
It is advantageous, when connection points 5 run perpendicularly to each other, to join the connection points 5 running perpendicularly to each other, for example, at their converging ends via rounded connection points 6. The radii of rounded connection points 6 enclosing rounded corners 2 are proportional in dimension to the lengths of linear connection points 5. The following table specifies the radii of the curved connection points for square cushion portions 3, 4 with rounded corners and for different side lengths. The table shows the side lengths, i.e. the lengths of linear connection points 5, and the associated radii of the curved connection points 6.
It can be seen from the above that the radii of curved connection points 6 change by the same factor as the lengths of linear connection points 5. In the case of rectangular cushion portions, the factor by which the radii change is the same as the factor by which the average of the short and the long side lengths changes.
The graph in
It can be seen that the bursting pressures are 0 to 12% higher when the cushion portion is arranged at an angle of 45° relative to threads 7, 8 than in the case of the circular cushion portion and the cushion portion arranged at 90° relative to threads 7, 8.
When the orientation of threads 7, 8 changes by a particular angle, for example, by an angle of 45°, the arrangement in the gas cushion of cushion portions 3 and 4 formed by the linear and rounded connection points 5 and 6 changes accordingly, with an approximate 45° orientation relative to threads 7, 8 being kept.
| Number | Date | Country | Kind |
|---|---|---|---|
| 20 2013 004 273.7 | May 2013 | DE | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/IB2014/000690 | 5/7/2014 | WO | 00 |
