The invention relates to an airbag module for protection of a vehicle occupant according to the introductory section of patent claim 1.
Safety systems are known which are intended to protect a person sitting in a motor vehicle in the case of a sudden deceleration of the travel movement, as the person sitting in the vehicle is flung contrary to the deceleration movement against a base located in the vehicle, for example the instrument panel, the front seat, the side wall etc. Without the named safety systems, this often leads to serious injuries of the vehicle occupant(s), as then no adequate protection is present in particular for the head and the thorax of the vehicle occupants.
Such safety systems particularly include safety belts and airbag devices. An airbag device, as is known, comprises an inflatable airbag, which is accommodated for example, in the steering wheel hub cover, in the instrument panel and/or in the side wall cladding of the motor vehicle. In case of collision of the vehicle against a fixed resistance, an acceleration sensor activates a gas generator, which is ignited within an extremely short time and inflates the airbag with filling gas. For this purposed, the cover or the cladding tears open at a defined point and frees the path for the airbag which is filling with gas. The affected person then sinks into the airbag, which considerably decreases the load which occurs during the sudden deceleration of the vehicle movement.
An airbag device is known from U.S. Pat. No. 4,966,388 in which an airbag is accommodated in a side door to the side of a vehicle occupant, whereby the airbag is inflated by a gas generator when a side collision occurs, so that the inflated airbag takes up a space between the side door of the vehicle and the vehicle occupant. A disadvantage of this airbag system is that the gas which is issuing from the gas generator is very hot, which means that it can damage the airbag or even set it alight, and can injure the vehicle occupants.
A flame protection device is known from U.S. Pat. No. 6,419,266 B, in which the airbag is folded together at the gas generator at the beginning. The device also includes a deflector for accommodation and deflection of the hot gases of the gas generator. This deflector consists of a single expandable metal ribbon, which is located between the gas generator and the airbag. This metal ribbon exhibits a tubular form with a closed circumferential jacket. When the gas generator is activated, the gas is transported into the airbag after it has passed the deflector through side openings in said deflector. As the metal ribbon of the deflector is folded together in several layers before activation of the gas generator, it is difficult to mount. In addition, its tubular form means that it is more complicated and more expensive to manufacture.
The invention is based on the task of creating an airbag module of the type named at the beginning which is as far as possible non-inflammable and which is also easy and inexpensive to manufacture and mount.
The invention is based on the recognition that the heat which occurs when the gas suddenly leaves the gas generator can damage the airbag and can injure the vehicle occupant and therefore the heat which is generated has to be effectively captured before it reaches the airbag.
The task which is set is solved in accordance with the characteristics of the main claim by means of an airbag module in which the expandable gas deflection device is designed in the form of a deformable ribbon, which exhibits a spiral form in cross section, whereby the radial ends of the ribbon cover each other when the gas generator is deactivated.
According to this, the deformable ribbon does not have a closed tubular form, as the free longitudinal edges of the ribbon overlap. This means that the ribbon which serves as a deflector for the gas which emerges from the gas generator can be manufactured and mounted more easily. The spiral form can also be implemented by means of two cylinder segments which overlap one another as regards their circumference.
According to one form of the object of the invention, the deformable ribbon surrounds the gas generator placed in the airbag as regards the circumference, if the airbag module or the gas generator are in non-activated state, so that the free longitudinal edges, seen in cross section, cover the radial ends of the ribbon.
Furthermore, the deformable ribbon is formed in such a way that when the gas generator is activated, the issuing gas unfolds the spiral form of the deformable ribbon to blow up the airbag, and this ribbon lies against the inner walls of the airbag under the pressure of the gas. This means that the free longitudinal edges of the deformable ribbon flap away from the gas generator and towards the airbag, whereby the diameter of the spiral form is increased.
As the deformable ribbon is preferably made of a flexible and heat resistant plastic or metal material, the gas which is hot because of the ignition in the gas generator first strikes the ribbon, which absorbs a part of the heat and energy of the gas. Extremely hot gas can therefore no longer be conveyed into the airbag to be inflated. This means that damage to the airbag and risk of injury to the vehicle occupants to be protected, in particular by the effects of heat, is avoided.
According to a further form of the airbag module according to the invention, a further airbag can be located between the deformable ribbon and the airbag, which is connected with the outer airbag and the gas generator from the point of view of flow. In the case of this variant, the deformable ribbon opens until it lies against the inner walls of the inner airbag. In this process, further heat energy is absorbed by the inner airbag, and the effect of the heat of the gas is reduced immediately following exit from the gas generator.
Furthermore, when the gas generator is activated, the circumference of the deformable ribbon is limited by its own dimensions and/or by the walls of the surrounding airbag.
Although the radial ends of the spiral-shaped ribbon are open for the exit of the gas, it can be useful if the deformable ribbon exhibits at least one gas outflow opening on its circumference. This is particularly useful if a further inner airbag is not present, e.g. in the case of so-called curtain-type window airbags, in which the gas is intended to exit into the airbag rapidly and over as large and area as possible.
Also such an airbag of a window airbag can, for example, exhibit at least one seam directed towards the circumference of the deformable ribbon. This then serves for defined limitation of the expansion of the deformable ribbon following activation of the gas generator.
Finally it is provided that the gas generator, the airbag or the airbags and the deformable ribbon are connected to each other in fixed fashion at least one point. The airbag module itself is, for example, fixed to a roof or window rail, in a steering wheel bowl or the instrument panel of the motor vehicle.
In the following text, the invention will be described in more detail in several embodiments, using the attached drawings.
The drawings are as follows:
The airbag module 1 shown in
Deformable ribbon 7 consists of a flexible and heat-resistant plastic or metal material and has a spiral form according to
On activation of gas generator 8, the issuing gas unfolds the spiral form of deformable ribbon 7 and, under the pressure of the gas, takes on the form and position shown by the dash-dot-dash line shown in
The circumference of deformable ribbon 7 is therefore limited by the walls of the surrounding inner airbag 5. If inner airbag 5 exhibits a larger volume, the enlarging circumference of deformable ribbon 7 is itself limited by its expansion. The gas, which is still under pressure, continues to enter the interior of outer airbag 4 gas through flow openings 10 inserted in inner airbag 5 and shown in schematic form, and also expands outer airbag suddenly. This state of the airbag module is shown in
As can also be seen from
In the case of the embodiment according to
Gas generator 8 is wound round at least in part by deformable ribbon 7, in fact in a similar way as shown in
Airbag 4 exhibits two T-shaped seams 16 at a distance to one another. When spiral-shaped ribbon 7 unfolds, its circumference expands to the extent that it reaches T-shaped seams 16. Then the gas which continues to flow out at the radial ends and at gas outflow opening 15 from gas generator 8 ensures complete inflation of airbag 4.
According to the embodiment according to
Number | Date | Country | Kind |
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10 2004 038 459.2 | Aug 2004 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP05/08399 | 8/3/2005 | WO | 00 | 2/6/2008 |