Abstract:
A side airbag for installation into a motor vehicle, a vehicle seat with such a side airbag and a motor vehicle with such a vehicle seat are described. The side airbag comprises at least one mounting device for mounting the side airbag on the backrest of the vehicle seat, an outer skin with a first side wall extending forwards, when viewed in the vehicle direction, and a second side wall connected to the first side wall. In order to be able, at as low a cost as possible, to protect the passengers to be protected better against a movement towards the middle of the vehicle, the second side wall extends essentially cross-ways to the vehicle direction when the outer skin is fully deployed and free from external forces, so that at least a third side wall connecting the first two side walls is present.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a 371 U.S. National Stage of International Application No. PCT/SE2011/050909, filed Jul. 5, 2011, which claims priority to German Patent Application No. 10 2010 027 401.1, filed Jul. 15, 2010. The disclosures of the above applications are incorporated herein by reference. 
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to a side airbag for installation into a motor vehicle, a vehicle seat with such a side airbag and a motor vehicle with such a vehicle seat. 
     Side airbags are in widespread use in vehicle safety technology. They are usually arranged either in a side cheek of a vehicle seat facing outwards, i.e. towards the vehicle internal structure, or in the side structure of the motor vehicle, and inflate in the event of a detected relevant accident, in particular a side crash, between the vehicle passengers to be protected and the vehicle internal structure, in order to prevent the vehicle passenger from striking against the vehicle internal structure. In the inflated state, such side airbags essentially extend in the vehicle longitudinal direction, wherein the side airbags comprise two side walls being essentially parallel to one another, wherein the side wall facing the passenger forms the impact surface and the opposite side wall forms the support surface. As a rule, such side airbags are so-called “2D-airbags”, i.e. airbags wherein the two side walls are directly connected to one another via an edge region. 
     The movement of the passenger towards the centre of the vehicle can of course not be prevented by such a side airbag. Vehicle seats with a side airbag have therefore been proposed, wherein said side airbag is located in the side cheek of the vehicle seat facing inwards, so that this side airbag inflates in case of need on the vehicle inner side of the vehicle passenger. The side airbag extends, like another side airbag also, essentially in the longitudinal direction of the vehicle. Such side airbags usually have the problem that they do not find suitable support without further measures and can therefore offer only a small degree of side support for the passenger. 
     PRIOR ART 
     On the one hand, an attempt has been made to solve the problem of the lack of side support with outwardly lying tethers, but this involves the drawback of costly assembly. Such a side airbag is described for example in GB 2357999 A. 
     It has further been proposed to provide a side airbag on the inside on each of two adjacent backrests; both side airbags have to be ignited in order that the side airbags mutually offer a certain degree of support. Such a system is proposed for example by GB 2309440 A. This also has several drawbacks: on the one hand, the desired side support can hardly be achieved, especially when the adjacent vehicle seat is not occupied, and on the other hand it necessitates the presence and simultaneous ignition of two side airbags. This is disadvantageous, inasmuch as each additional airbag naturally means additional vehicle weight and each airbag inflated during an accident involves considerable additional repair costs. Finally, the two adjacent side airbags can ideally support against one another only when the adjacent seats are adjusted essentially identically. 
     SUMMARY OF THE INVENTION 
     Proceeding from this, the present invention poses the problem of improving the prior art in such a way that good protection against a passenger movement towards the middle of the vehicle is provided, wherein the additional weight and the repair costs in the event of an accident are to be kept as low as possible. Furthermore, the side airbag should offer good protection irrespective of the seat occupancy. In the case of use in seats separated from one another, especially in the case of front seats in a passenger car, the safety system should further work properly irrespective of the individual seat adjustment. 
     According to the invention, a side airbag with two side walls is used, wherein the latter, when the side airbag is completely deployed, but free from external forces, do not extend parallel to one another, but enclose a relatively large angle, in particular of 90° or more. This means that the side airbag is usually not a 2D airbag, but rather a 3D airbag, which as a rule is produced from at least three cuttings, and that a third side wall must be present which connects the first two side walls to one another. 
     As a result of the chosen design, the side airbag can in particular supports itself on an adjacent backrest, so that it is possible, in particular, that only one such side airbag is required, which gives rise to the aforementioned advantages in respect of vehicle weight and incurred repair costs. A further advantage is that a side airbag constructed according to the invention can easily be constituted such that—especially in the case of the use of separate, adjacent seats—it “automatically seeks” its necessary support according to the circumstances, irrespective of the specific situation (in particular the adjustment and occupancy of the seats). 
     Preferred embodiments of the invention are defined in the sub-claims, as well as in the embodiments of the invention represented in greater detail by reference to the figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the figures: 
         FIG. 1  shows a first embodiment of a side airbag according to the invention in a schematic, perspective view, 
         FIG. 2  shows the side airbag from  FIG. 1  in a horizontally running cross-section, 
         FIG. 3  shows a second example of embodiment of the first embodiment of the invention in a representation corresponding to  FIG. 2 , 
         FIG. 4  shows a third example of embodiment of the first embodiment of the invention in a representation corresponding to  FIG. 2 , 
         FIG. 5  shows a fourth example of embodiment of the first embodiment of the invention in a representation corresponding to  FIG. 2 , 
         FIG. 6  shows the assembled side airbag from  FIGS. 1 and 2  with a completely deployed outer skin in the case of protection of a passenger sitting on the left-hand side, 
         FIG. 7  shows the side airbag from  FIG. 6  in the case of protection of a passenger sitting on the right-hand side, 
         FIGS. 8-10  show essentially the situation depicted in  FIG. 6  with different seat positions, 
         FIGS. 11-13  show essentially the situation depicted in  FIG. 7  with different seat positions, 
         FIGS. 14-15  show an accident situation with two passengers sitting beside one another, 
         FIG. 16  shows a second embodiment of the side airbag according to the invention in a representation corresponding to  FIG. 2 , 
         FIG. 17  shows a schematic representation of a seat bench with a side airbag represented in  FIG. 16 , 
         FIG. 18  shows the situation depicted in  FIG. 17  in the case of an accident with a passenger on the seat bench, 
         FIG. 19  shows the situation depicted in  FIG. 18  with two passengers and 
         FIGS. 20-24  show alternative possibilities as to how the desired shape of the side airbag can be generated. 
     
    
    
     DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS 
     Two embodiments of the invention are described below, wherein the first embodiment relates in particular to the case where two seats are present which are arranged beside one another, but essentially independent of one another. This is especially the case in the front seat row of motor vehicles, but can also relate to rear seat rows with individual seats. 
     The second embodiment of the invention relates to the use in a seat bench, in particular a rear seat bench of a motor vehicle. 
       FIGS. 1 and 2  show a representation of a side airbag according to the invention, wherein  FIG. 2  shows a horizontal cross-section through the representation in  FIG. 1 . Side airbag  10  comprises an outer skin  12  and a gas generator  20 , from which bolts  22  for mounting the side airbag extend through the outer skin  12 . The outer skin  12  comprises when viewed geometrically—and as a rule also physically—three parts, i.e. a lateral surface  14 , whose surface normals essentially lie in the horizontal plane, and two caps  16  and  18 , whose surface normals lie essentially vertically. “Horizontal” and “vertical” is understood here to mean the situation with an installed and fully deployed outer skin  12 , wherein the precise position naturally depends on the position of the backrest. The outer skin  12  encloses in a common way a gas compartment in which the gas generator  20  serving as an inflator is disposed. 
     In  FIG. 2  the arrow L indicates (in the installation situation) the vehicle longitudinal direction and the double arrow Q indicates the vehicle transverse directions. It can be seen especially from  FIG. 2  that the lateral surface  14  has an essentially triangular cross-section (which is imposed upon it by the two caps  16 ,  18 ), so that the lateral surface  14  is divided into three side walls, i.e. the first side wall  14   a , the second side wall  14   b  and the third side wall  14   c . First side wall  14   a  and second side wall  14   b  extend essentially from the mounting device of the side airbag, i.e. from the region in which the bolts  22  of the gas generator  20  pass through the lateral surface  14 . That is to say that the first side wall  14   a  and the second side wall  14   b  meet in the region of the side cheek of the backrest in which the side airbag  10  is installed. The third side wall  14   c , which connects the first wall  14   a  and the second wall  14   b , lies essentially opposite the mounting device, i.e. the bolts  22 . It can directly be seen in  FIG. 2  that the first side wall  14   a  extends from the mounting device essentially forward in the vehicle longitudinal direction, but in a slightly slanting way, and that the second side wall  14   b  extends essentially in a vehicle transverse direction. The effect of this is that the inner angle α between the first side wall  14   a  and the second side wall  14   b  is greater than 90°, here approx. 120°. Furthermore, it can be seen from  FIG. 2  that the second side wall  14   b  is longer than the first side wall  14   a.    
       FIG. 3  shows a second example of embodiment, wherein the first side wall  14   a  essentially extends precisely in the vehicle longitudinal direction L and the second side wall  14   b  essentially extends precisely in vehicle transverse direction Q. As a result, the cross-section of the outer skin  12  is essentially a right-angled isosceles triangle, i.e. a “quarter slice of cake”. 
       FIG. 4  shows a third example of embodiment, wherein the inner angle α between first side wall  14   a  and second side wall  14   b  is very large and close to 180°, so that the third side wall  14   c  is roughly as long as the sum of the first two side walls  14   a  and  14   b.    
       FIG. 5  shows a fourth example of embodiment, in which it can be seen, on the one hand, that the cross-sectional shape of the outer skin  12  can also be more complex and that, on the other hand, the second side wall  14   b  can even extend somewhat backwards, which, as will be seen later, is often preferred. 
       FIG. 6  shows the side airbag from  FIGS. 1 and 2  in the installed and completely deployed state in the case of an impact from the right with the presence of a passenger  40  sitting on a left-hand seat  24 . 
     As has already been mentioned, the embodiment of the invention relates to an installation situation with two adjacent vehicle seats, i.e. a left-hand vehicle seat  24 , which for example can be the driver&#39;s seat, and a right-hand vehicle seat  26 , which can for example be the front passenger seat. The left-hand vehicle seat  24  as usual comprises a seat cushion  24   a  and a backrest  24   b , and likewise the right-hand vehicle seat  26  with a seat cushion  26   a  and a backrest  26   b . As can be seen directly from  FIG. 6  and also from  FIG. 7 , only one side airbag  10  is present, as has been previously described, and the latter is connected with its bolts  22  serving as a mounting device to the seat frame of the inner cheek of one of the two vehicle seats  24 ,  26 , i.e. the left-hand vehicle seat  24  here. A further side airbag acting between the two seats  24 ,  26  is not provided, nor is it required. 
       FIG. 6  shows the situation with vehicle seats  24 ,  26  adjusted essentially parallel to one another in the case of a side crash from the right, wherein only the left-hand vehicle seat  24  (which can be the driver&#39;s seat) is occupied by a passenger  40 . It can be seen that the second side wall  14   b  extends up to the backrest  26   b  of the right-hand vehicle seat  26  and is supported on the latter, i.e. forms the support surface, whereas the first side wall  14   a  forms the impact surface for the passenger  40  sitting on the left-hand side. 
       FIG. 7  shows the situation depicted in  FIG. 6  in the case of a side impact from the left, wherein a passenger  42  is present only on the right-hand vehicle seat  26  (in the case of a left-hand drive vehicle, this can of course only occur in practice with separated individual seats at the back of the motor vehicle). It can be seen that the outer skin  12  is tilted counterclockwise essentially by 90°, so that the outer skin  12  of the side airbag  10  is in this case supported by its first side wall  14   a , i.e. on the backrest  24   b  of the left-hand vehicle seat  24 , and that the second side wall  14   b  forms the impact surface. First side wall  14   a  and second side wall  14   b  have exchanged their function as compared to the situation depicted in  FIG. 6 . This takes place “automatically”, i.e. without any additional active control, depending on the accident situation. 
       FIGS. 8 to 10  essentially show the situation depicted in  FIG. 6  with different adjustments of the two vehicle seats  24 ,  26  with respect to one another, also in the case of an impact from the right. In the adjustments of  FIGS. 8 and 9  (right-hand vehicle seat  26  farther back than left-hand vehicle seat  24  or vehicle seats at the same height), the first side wall  14   a  forms the impact surface and the second side wall  14   b  the support surface. It can be seen from  FIG. 8  that it may often be advantageous if the second side wall  14   b  extends somewhat backwards. In the case shown in  FIG. 10 , i.e. when the right-hand vehicle seat  26  is positioned relatively well in front of left-hand vehicle seat  24 , a part of third side wall  14   c  can also function as support surface. Furthermore, the side airbag  10  often does not reach its complete volume in this case. 
       FIGS. 11 to 13  show the situation depicted in  FIG. 7  with different seat adjustments, also in the case of an impact from the left. In the adjustments of  FIGS. 11 and 12  (right-hand vehicle seat  26  farther forward than left-hand vehicle seat  24  or vehicle seats at the same height), the first side wall  14   a  forms the support surface and the second side wall  14   b  forms the impact surface. In the case shown in  FIG. 13 , i.e. when the left-hand vehicle seat  24  is located relatively well in front of the right-hand vehicle seat, a part of the third side wall  14   c  can serve as the impact surface. 
       FIGS. 14 and 15  show situations with two passengers, wherein  FIG. 14  shows the situation in the case of a side impact from the left and  FIG. 15  shows the situation in the case of a side impact from the right. If both seats are occupied, at least a part of the transfer of force can also take place via the person sitting beside. It can also be seen from  FIGS. 14 and 15  that “normal” side airbags (left-hand side airbag  30  and right-hand side airbag  32 ) are usually of course also present. 
     It is a characteristic of the first embodiment just described that the outer skin  12  of the side airbag  10  automatically seeks its suitable support surface and different areas of the lateral surface can serve both as an impact surface and as a support surface, depending of the accident situation. Furthermore, it is typical that the first side wall  14   a  and the second side wall  14   b  extend away from the mounting region of the airbag. 
       FIG. 16  shows a side airbag according to a second embodiment of the invention in a representation corresponding to  FIG. 2 . The outer skin  12  of this side airbag  10  also comprises a lateral surface  14  and two caps  16 ,  18  (not represented). The shown cross-section through the outer skin  12  (which essentially corresponds to the shape of the caps) has an essentially rectangular cross-section, so that the lateral surface  12  has four side walls, namely a first side wall  14   a , a second side wall  14   b , a third side wall  14   c  and a fourth side wall  14   d . The bolts  22  of the gas generator (which form the mounting device) extend through the second side wall  14   b  and the fourth side wall  14   d  extends parallel to this second side wall  14   b . First side wall  14   a  and third side wall  14   c  extend parallel to one another and connect the second and fourth side wall. The second and fourth side wall extend in transverse direction Q of the motor vehicle, the first and third side wall extend in longitudinal direction L. As can be seen from  FIGS. 18, 19 , first and third side wall  14   a ,  14   c  virtually always form the impact surfaces, whereas the second side wall  14   b  forms the support surface, wherein, in the event of a vehicle impact from the left, i.e. when a passenger sitting on the right-hand side strikes the outer skin  12 , i.e. the third side wall  14   c , the left-hand section  14   b ′ of the second side wall  14   b  essentially takes over the support function and vice versa. In contrast with the first embodiment, therefore, there is a fixed allocation of the side walls to a function. 
     The previously described side airbags are “conventional” 3D-airbags comprising at least three cuttings, wherein the desired cross-sectional shape is generated by the caps. This is however not imperative, as is shown by way of example in  FIGS. 20 to 24 , wherein the representations of these figures correspond to  FIGS. 2 to 5  both with respect to their cross-sectional plane and with respect to their orientation: 
     In the example of embodiment of  FIG. 20 , the desired cross-sectional shape is generated by an inner tether  50 , which forces the outer skin into a heart-shaped cross-section, in such a way that the third side wall  14  is concave. Something similar is shown in  FIG. 21 , but with two tethers  50 . 
     In the examples of embodiment of  FIGS. 22 and 23 , the desired shape (first side wall  14   a  extending forward and second side wall  14   b  extending sidewards) of the outer skin  12  is achieved by the fact that two airbag skins  54 ,  56  are placed one upon the other, wherein they are connected to one another by means of at least one overflow opening. 
     The example of embodiment of  FIG. 24  is similar to the example of embodiment of  FIG. 20 , with the difference that here the second side wall  14   b  is forced into a concave shape by the inner tether  50 . This means that, whilst the second side wall extends overall crosswise to the vehicle direction, not all the sections of this second side wall necessarily do so. It may be advisable in this case to provide an outer tether  52  spanning wholly or partially over the second side wall  14   b . Said outer tether  52  can in a case as is shown for example in  FIG. 7  also form the impact surface or a part thereof. 
     The described side airbags usually comprise, like airbags arranged on the outer side of a backrest too, a ventilation device, for example in the form of a ventilation opening in the outer skin. Since in some cases only a very small amount of ventilation is required (see for example  FIGS. 6 and 7 ), but in other cases very strong ventilation is required (see for example  FIGS. 10, 14 and 15 ), it may be advisable to provide an adaptive ventilation device, which increases its effective diameter with increasing internal pressure. Such an adaptive ventilation device can comprise for example a membrane with at least one hole. Other adaptive ventilation devices are however also known. 
     LIST OF REFERENCE NUMBERS 
     
         
           10  side airbag 
           12  outer skin 
           14  lateral surface 
           14   a  first side wall 
           14   b  second side wall 
           14   b ′ left-hand section 
           14   c  third side wall 
           14   d  fourth side wall 
           16  first cap 
           18  second cap 
           20  gas generator 
           22  bolt 
           24  left-hand vehicle seat 
           24   a  seat cushion 
           24   b  backrest 
           26  right-hand vehicle seat 
           26   a  seat cushion 
           26   b  backrest 
           28  seat bench 
           28   a  seat cushion 
           28   b  backrest 
           30  left-hand side airbag 
           32  right-hand side airbag 
           40  passenger sitting on the left 
           42  passenger sitting on the right 
           50  inner tether 
           52  outer tether 
           54  first airbag skin 
           56  second airbag skin 
         L longitudinal direction of the motor vehicle 
         Q transverse direction of the motor vehicle