SIDE AIRBAG MODULE WITH AN INTERNAL GUIDE FIN

DESCRIPTION

[0001] The present invention generally relates to airbags for use as an impact protection device for an occupant of a motor vehicle. More specifically, it relates to a impact side airbag module with a gas generator and an airbag that unfolds into an interior of a motor vehicle when the associated gas generator activates.

[0002] DE 10 2004 044 256 A1 discloses an existing design of a side airbag module include a gas generator mounted inside a vehicle seat. The gas generator is mounted on one side of the seat structure and projects into a side bolster of the vehicle seat back pointing in a direction of travel. An airbag is disposed within the side bolster and arranged around and attached to the gas generator. A front end of the airbag near the end of the side bolster is attached to a seam in the upholstery covering the side bolster.

[0003] With the above described known airbag arrangement, where the airbag is accommodated in the side bolster of the vehicle seat back, there is the disadvantage that the airbag has to be folded into an opening formed into the side bolster of the vehicle seat and the front end has to be attached to the upholstery. This makes assembling such a side airbag quite complex. A further disadvantage is that when the gas generator is activated, the gas stream which is released expands into the airbag without a specific direction, potentially resulting in a less than optimal airbag deployment.

[0004] In view of the above, the invention is based on the problem of creating an improved side airbag module according to the generic characteristics which can be easily installed into a vehicle and which exhibits good deployment characteristics.

[0005] The solution to this problem, including advantageous embodiments and further developments, results from the contents of the claims which follow this description.

[0006] The present invention includes a large guide fin disposed within an interior of a folded side impact airbag. The guide fin is attached to a component which is fixed to the vehicle. The airbag is disposed over the guide fin for improved folding and packaging within a seat of the motor vehicle. A further advantage is that a substantially flat form factor for the side airbag module is possible. The large-area of the guide fin also advantageously ensures improved targeted expansion and improved unfolding of the airbag during deployment.

[0007] According to one embodiment of the present invention, the guide fin helps define a desired shape of the folded airbag. The guide fin also improves the targeting of the airbag while unfolding during deployment.

[0008] In another embodiment the guide fin includes two plates, arranged at a distance from one another that form a gas guide channel communicating with a gas generator. At a rear end opposite the expansion direction of the airbag the two plates are connected to one another by means of an arcuate connecting wall which surrounds an exterior of the gas generator. The connecting wall is attached to the gas generator so that the guide fin is secured to the gas generator.

[0009] In yet another embodiment of the present invention, the plate oriented toward the outer side of the vehicle when the side airbag module is installed in the vehicle is longitudinally longer than a shorter plate lying opposite. The space which lies in front of the shorter plate in the expansion direction, which is also limited on the outer side by the larger plate, serves as a packing space for the folded airbag. [0010] According to an alternative embodiment of the present invention, two identical plates may be arranged substantially parallel to one another. This has the advantage that a gas stream from the gas generator is guided to the front end of the airbag which is folded over the guide fin, so that unfolding is initiated from the front end of the airbag as it emerges from the side airbag module. [0011] According to another aspect of the invention, the gas guide channel is completely formed between the two plates of the guide fin.

[0012] In another example, the plates of the guide fin may be formed with thin walls. This results in a very flat module including the gas guide channel. Also, when the gas stream is guided between the two plates of the guide fin, the plates may move or oscillate and hot gases of the gas stream may be cooled. [0013] The cooling of the gas stream is improved if, according to an embodiment of the invention, the guide fin consists of flexible material. In this arrangement the guide fin may consist of a plastic material. This has the additional advantage that, for example, in case of a fire during the manufacturing or transport process, the fin loses its rigidity or melts and therefore the side airbag module behaves in a neutral manner if the gas generator activates due to high temperatures. Flexible material should be understood as basically rigid in order to provide a

stiffness of the complete side airbag module, but also flexible in order to provide such cooling effect with the described movement of the plates.

[0014] According to another embodiment of the invention, it is provided that the airbag which is folded over the guide fin is also attached to a fabric of a seat with regard to by means of at least one tear seam.

[0015] According to one embodiment of the invention, it is provided that the gas generator is formed as an axially extending gas generator oriented along a height of the plates.

[0016] In order to manufacture a pre-mounted airbag unit which can easily be built into the vehicle seat, it can be provided that the airbag module surrounded by an outer cover. The outer cover is preferably flexible and of light weight and can include a shrinkable foil.

[0017] As an alternative to the outer cover including a shrinkable foil it can be provided that the airbag is fixed by tear seams in its folded form, whereby the tear seams can also extend through the guide fin.

[0018] According to one embodiment of the invention, at least one bolt is fixed to the gas generator, which extends through the plate on the inner side of the vehicle and is also fixed to the component which is fixed to the vehicle.

[0019] Finally, according to one embodiment of the invention, it is intended that the side airbag module is attached to the structure of a vehicle seat in the motor vehicle.

[0020] Fig. 1 is a side view of a vehicle seat with a side airbag module arranged in the side bolster of the seat back;

[0021] Fig. 2 is a sectional view of the side cheek of the motor vehicle seat including the side airbag module;

[0022] Fig. 3 is a perspective view of a guide fin with an airbag of the side airbag module folded over the guide fin; and

[0023] Fig. 4 is a sectional view through the side airbag module of an alternate embodiment.

[0024] A vehicle seat 10 shown in schematic form in Fig. 1 has a seat cushion

11 and a backrest 12 onto which a headrest 13 is attached. Backrest 12 is arranged to be adjustable in relation to seat cushion 10 by means of backrest adjustment 14. An adjustment 15 for changing a hardness of the backrest is also provided in the backrest 12. A side bolster 16 projecting forwards from the backrest 12 includes a side impact airbag module 8 having a gas generator 17 and an airbag 18. [0025] As can be seen in more detail in Fig. 2, a recess 19 is provided within the side bolster 16 of the backrest 12 to accommodate the side airbag module 8. The upholstery 9 of the side bolster 16 includes a break location 25 for opening the side bolster 16 upon activation of the airbag module 8 to allow the airbag 18 to exit during airbag deployment.

[0026] A guide fin 20 is also located in the recess 19 of the side bolster 16.

The guide fin 20 includes two plates 21 arranged at a distance from one another and form a gas guide channel 22 between them. A rear end the two plates 21 are connected to one another by means of a connecting wall 23 which surrounds an exterior of the gas generator 17 and attaches the guide fin 20 to the gas generator 17. At one side, the gas generator 17 is fixed to a vehicle seat frame 26. The frame

26 forms a component which is fixed by a fixing means 27 to the airbag module 8.

The airbag 18 is arranged over guide fin 20 in a compact folded arrangement in such a way that guide fin 20 is located inside the airbag module 8.

[0027] From Fig. 3 it can be seen how airbag 18 is arranged over the guide fin

20. The airbag 18 also surrounds the connecting wall 23 on its outside and is penetrated by the fixing means 27. The end of the guide fin 20 points in an expansion direction of the airbag 18. In some examples, the plates 21 are not attached by the fixing means 27 to the component or vehicle seat frame 26.

[0028] Returning to Fig. 2, the airbag 18 is folded over guide fin 20 and surrounded on its exterior by a shrinkable foil 24. This creates a pre-assembled unit including the gas generator 17, guide fin 20, folded airbag 18 and the exterior shrinkable foil 24. Thus, the unit only has to be connected with vehicle seat frame

26 by means of the one or more fixing means 27.

[0029] An alternative not shown in the drawing omits the shrinkable foil.

Instead, the airbag can be fixed in its compact folded state and location by means of tear seams. The tear seams can additionally extend through the guide fin 20 and the plates 21.

[0030] When the gas generator 17 is activated, a gas stream flows via the gas guide channel 22 to a front end 18a of airbag 18. Thus, the unfolding airbag 18 tears open the break point 25 in the side cheek 16 and unfolds out of vehicle seat

10.

[0031] In the case of the embodiment of the side impact airbag module 36 shown in Figure 4, the two plates forming a guide fin 29 are formed with different lengths. An outer plate 30, which faces towards the outer side of vehicle 33 when it is installed in the vehicle and corresponds to the length of the folded airbag 18, is

longitudinally longer than the opposite plate facing towards the inner side of the vehicle 34, which is formed as a shorter plate 31. Shorter plate 31 has just enough length to direct the gas exiting from an activated gas generator 17 in the expansion direction 35 of the expanding airbag. This arrangement increases the size of a packing space 32 in the expansion direction 35 of the gas in front of the short plate 31. The airbag 18 is folded into the packing space 32. Around its exterior, the folded airbag 18 is surrounded by an exterior cover, for example, the shrinkable foil 24. In this embodiment, a fixing means 27 is formed on to the gas generator 17. The fixing means 27 penetrates through the short plate 31 and is suitable for fixing the side airbag module to a component fixed to the vehicle, preferably to the vehicle seat such as that described in relation to Figures 1 to 3.

[0032] The guide fins 20 and 29, in some examples, may be made of a flexible material. The flexible material may include various plastic materials. The gas generator 17 has a minimum activation temperature, and the flexible material may be configured to lose rigidity or melt, at a temperature lower than the minimum activation temperature. Thus, instead of the guide fin 20 or 29 directing and focusing the gas if the gas generator is accidentally activated in, for example, a fire, the flexible material will lose rigidity before the gas generator activates. This will cause the gas to expand in a more diffuse manner instead of being directed by the guide fin. This results in a more neutral response by the airbag module to an accidental high temperature activation of the gas generator 17. [0033] According to an embodiment not a shown in the figures the airbag 18 can be secured to the seat fabric by a connector which could include a tear seam or a tear line e.g. a perforation or material weakening. In case of an exterior cover 24

enclosing the folded airbag 18 the cover 24 may be connected to the seat fabric by such connector. Advantageously the connector is formed of flexible material and is attached to the seat fabric in the area of the split seam which opens for deployment of the airbag 18. The connector can be a separate element or maybe integrally formed with either the airbag 18 or the exterior cover 24.

[0034] As a person skilled in the art will readily appreciate, the above description is meant as an illustration of implementation of the principles this invention. This description is not intended to limit the scope or application of this invention in that the invention is susceptible to modification, variation and change, without departing from spirit of this invention, as defined in the following claims.