Abstract:
Disclosed is a vehicle seat ( 10 ) for a motor vehicle having a backrest ( 14 ) with a seat-mounted side airbag ( 20 ) having a first side wall ( 22 ) facing the occupant and a second side wall ( 24 ) facing the outside of the vehicle. The side airbag ( 20 ) is located on the side of the backrest ( 14 ) facing the outside of the vehicle, and the side airbag ( 20 ) includes a first ventilation opening ( 30 ) in the second side wall, the ventilation opening being at least throttled on lying against an object, so that a ventilation of the airbag is adapted as a function of the size of the occupant. The vehicle seat ( 10 ) is height adjustable so that, depending on the height adjustment of the vehicle seat, the first ventilation can be closed by the inner structure of the vehicle.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to German Patent Application No. 10 2009 016 606.8, filed Apr. 8, 2009 and PCT/EP2010/001968, filed Mar. 29, 2010. 
     TECHNICAL FIELD OF THE INVENTION 
     The invention relates to a vehicle seat for a motor vehicle with a side airbag and to a motor vehicle with such a vehicle seat. 
     BACKGROUND OF THE INVENTION 
     The use of side airbags is widespread in vehicle technology. Such side airbags serve to protect the occupant to whom they are allocated in the case of a side impact or in the case of an accident in which the vehicle rolls over. For this function, the side airbag is arranged in or on the side bolster of the backrest of the motor vehicle seat or in the lateral structure of the motor vehicle, and in the case of an accident expands between the occupant and the vehicle structure, generally resting against the vehicle structure. The side airbag has a ventilation opening, so that, on impact of the occupant, gas can escape from the interior of the airbag through this ventilation opening and thereby impact energy is dissipated. Absent such a ventilation opening, the occupant would rebound back into the interior of the vehicle from the impact surface of the side airbag, which of course is not desired. 
     The problem exists that with given airbag volume and with given gas generator output, the size of the ventilation opening would have to be tuned in relation to the weight of the occupant, in order to achieve an ideal protective effect for the respective occupant. In the case of a heavy occupant, the ventilation opening would have to be relatively small, so that the side airbag remains relatively hard and the occupant is prevented from striking through onto the vehicle structure. In the case of a light occupant, the ventilation opening would have to be relatively large, in order to make the side airbag softer. 
     To solve the problem which has just been mentioned, U.S. Publication No. 2005/0184493 A1 proposes providing a first ventilation opening in a side wall of the side airbag, namely in the side wall pointing towards the inside, which also forms the impact surface. The position of this ventilation opening is selected so that it is covered by the shoulder region of a tall occupant, but is not covered by the shoulder region of a short occupant. If a tall, and hence generally heavier, occupant strikes onto the side airbag, the shoulder region blocks or throttles the ventilation opening and the side airbag remains accordingly hard. If, on the other hand, a short, and hence generally lighter, occupant strikes onto the impact surface of the side airbag, then this ventilation opening remains open and the side airbag shows a correspondingly soft behaviour. An adaption of the ventilation therefore takes place as a function of the size of the occupant. 
     A disadvantage here is firstly that the ventilation opening must be hit relatively precisely, in particular even when the occupant is not in his standard sitting position (out of position). A further disadvantage is that the adaptation of the ventilation takes place substantially “digitally”, which means that the ventilation is either open or closed. Graduations lying therebetween are relatively difficult to realise. 
     SUMMARY OF THE INVENTION 
     Starting from this, the present invention sets itself the problem of improving the prior art to the effect that the ventilation adaptation is substantially independent of the sitting position of the occupant at the onset of the accident. 
     According to the invention, the ventilation opening, through which the degree of hardness of the side airbag is set, is situated on the side wall of the side airbag pointing outwards, i.e. towards the side wall of the vehicle. It is not the shoulder region of the occupant, but rather the door of the vehicle, namely the region below the door shoulder, which therefore serves for the possible closing of this first ventilation opening. The control factor here as to whether the side airbag behaves in a hard or a soft manner in the case of a side impact is not directly the body size of the occupant, but rather the vertical adjustment of the vehicle seat, i.e. only indirectly the body size of the occupant. This means that the invention obligatorily presupposes a height adjustable vehicle seat. 
     If a height adjustability is present for the vehicle seat, then this is generally used at least on the driver&#39;s side, with a tall driver adjusting the seat low and a short driver adjusting the seat high. The position of the first ventilation opening can therefore be easily selected so that it comes to lie above the door shoulder of the door in the highest seat position and below the door shoulder of the door in the lowest seat position of the vehicle, when the side airbag is in its completely deployed state. This first ventilation opening is therefore closed by abutment against the door in the case of a tall occupant, i.e. with a low set seat, but not in the case of a short occupant, i.e. with a high set vehicle seat. This functions very reliably and independently of the actual sitting position of the occupant during the accident, and the sealing effect by the rigid structure of the door is very high. A further advantage is that a direct flowing of hot gases against the occupant is ruled out. 
     In preferred embodiments, the ventilation opening consists of several single openings, whereby a very fine tuning of the airbag hardness can be achieved. 
     The invention will now be explained in further detail by ways of preferred embodiments with reference to the appended figures. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, 
         FIG. 1  shows a schematic view onto a driver&#39;s seat, mounted in a motor vehicle, with a side airbag, wherein this side airbag is illustrated in completely deployed, but undisturbed state, 
         FIG. 2  shows the view of  FIG. 1 , with a tall occupant sitting on the vehicle seat, 
         FIG. 3  shows the view of  FIG. 2  after the occupant has struck the side airbag, 
         FIG. 4  shows the view of  FIG. 1  with a short occupant sitting on the vehicle seat, wherein the vehicle seat is situated in an upper vertical adjustment, 
         FIG. 5  shows the view of  FIG. 4  after the occupant has struck the side airbag, 
         FIG. 6  shows a perspective illustration of a situation-approximately corresponding to the situation of  FIG. 5 , 
         FIG. 7  shows a lateral view onto a vehicle seat with a side airbag and 
         FIG. 8  shows a ventilation opening which is covered by a covering cloth. 
     
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       FIG. 1  shows a vehicle seat  10 , namely a driver&#39;s seat, in the mounted state in the motor vehicle. The vehicle floor  40 , the vehicle roof  42  and the roof rail  44  can be seen schematically. On the outside, adjacent to the vehicle seat, the vehicle door  45  is situated, which comprises a main body  46  extending up to the door shoulder  47 , and a window frame  49 , of which an upper section can be seen here. When the side window  50  is closed, it extends between the door shoulder  47  and the window frame  49 . In addition, a storage compartment  48  can be seen, which is formed on the main body  46  of the vehicle door  45 . 
     The vehicle seat  10  has a schematically illustrated height adjustment  18 , by means of which the vertical position of the vehicle seat  10  can be set with respect to the vehicle floor  40 .  FIG. 1  shows the vehicle seat  10  in its lowest adjustment. Further, a side airbag  20  in its completely deployed state is illustrated in  FIG. 1 . In this completely deployed state, the side airbag  20  extends from the outer side bolster  14   a  of the backrest  14  forwards and substantially parallel to the vehicle door  45 . The side airbag  20  is filled by a gas generator which is, however, not illustrated here. 
     The side airbag  20  has a first side wall  22  pointing towards the occupant and a second side wall  24  pointing towards the outside. The first side wall  22  therefore serves as an impact surface and the second side wall  24  serves as a support surface. Two ventilation openings are provided, namely the first ventilation opening  30  and the second ventilation opening  38 . The first ventilation opening  30  serves to control the internal pressure, i.e. the hardness, of the side airbag  20  on impact of an occupant onto the impact surface of the first side wall  22 . For this, the first ventilation opening  30  is located on the outwardly-pointing second side wall  24  in the region of the height of the door shoulder  47 . As can be seen from  FIG. 1 , the first ventilation opening  30  is arranged in the second side wall  24  of the side airbag  20  so that with a completely deployed airbag  20  and with a height adjustment of the vehicle seat in its lowest position, it is situated below the door shoulder  47  of the vehicle door  55 . The second ventilation opening  38  is situated in a front region, approximately in the transition region between the first side wall  22  and the second side wall  24  and is arranged so that it remains open in every case. 
       FIG. 2  shows the view of  FIG. 1 , with a tall occupant G sitting on the vehicle seat  10 . 
       FIG. 3  shows the view of  FIG. 2 , after the tall occupant, as the result of an accident, has struck onto the first side wall  22  of the side airbag  20  and the latter is supported by the vehicle door  45 , namely its main body  46 , by means of its second side wall  24 . Owing to the position of the first ventilation opening  30  described above, the latter strikes onto the outer surface of the main body  46  of the vehicle door  45  below the door shoulder  47  and is thereby fully blocked or at least throttled. Because the main body  46  of the vehicle door  45  is a very rigid body, an almost complete blocking of the first ventilation opening  30  is practically always given, independent of the exact sitting position of the occupant. In this case, the ventilation of the side airbag  20  takes place exclusively via the second ventilation opening  38 , whereby the side airbag  20  remains relatively hard. 
       FIG. 4  shows the view of  FIG. 2 , when a short occupant K is sitting on the vehicle seat  10 . The vehicle seat  10  is set into an upper position corresponding to the size of the occupant K, as can also be seen from the illustration of the schematically illustrated height adjustment  18 . Through this raised position of the vehicle seat  10 , compared with the state shown in  FIG. 2 , the first ventilation opening  30  is situated above the door shoulder  47 . If, as illustrated in  FIG. 5 , the short occupant K strikes onto the first side wall  22  of the side airbag  20  and the latter rests by means of its second side wall  24  against the main body  46  of the vehicle door  45 , then the first ventilation opening  30  does not come in contact with the main body  46  of the vehicle door  45  and therefore remains open, because the side window is offset outwards with respect to the inwardly pointing surface of the main body  46  and in addition is generally destroyed in the case of a side impact, so that it does not offer any abutment surface in this case. The first ventilation opening  30  therefore does not come into abutment or only with very little force—if the side window  50  is reached—against a surface. Hereby, gas flows off both through the second ventilation opening  38  and also through the first ventilation opening  30 , and the side airbag  20  becomes soft accordingly. 
     From the preceding illustration of the invention, it can be seen that the second ventilation opening, which always has the same effective cross-section, serves for the rough tuning of the side airbag and therefore is primarily adjusted to the volume of the side airbag and the gas generator output, but not to the respective vehicle occupant. The first ventilation opening serves for the fine tuning of the side airbag as a function of the size of the occupant who is to be protected. The rough tuning and the fine tuning are fully decoupled from each other. 
     It can further be seen from the preceding illustration of the invention that it only functions optimally when the occupant who is to be protected carries out the applicable seat height adjustment for his body size. This is in fact generally the case, but particularly on the passenger side it can happen that the occupant does not carry out the applicable seat height adjustment, in particular that a short occupant sits too low, and in the case of an accident the first ventilation opening is therefore positioned below the door shoulder. Owing to the low weight of the short occupant, the first ventilation opening is, however, pressed with a smaller force against the door than by a tall occupant, so that it is generally not fully closed, which attenuates the effect of the “incorrect use”. As the side walls of the side airbag have a convex shape, the force transmission between the door and the second side wall  24  of the side airbag is largest in the middle of the second side wall  24 . It can therefore be advantageous to arrange the first ventilation opening  30  eccentrically, i.e. in a margin region of the second side wall  24 , in order to intensify the effect described above, namely that the first ventilation opening is not fully closed when it is pressed by a short (and light) occupant against the door. 
       FIG. 6  shows a situation which corresponds substantially to the one of  FIG. 5 , in a perspective illustration. It can be seen from this figure that the first ventilation opening  3  can also consist of several single openings  31 , here namely two. The same also applies to the second ventilation opening  38 . It is further indicated in  FIG. 6  that the first ventilation opening  30 , here therefore the two single openings  31 , can be covered with a covering cloth  36 , which improves the sealing effect in the case of an abutment against the vehicle door  45 . Such a covering cloth is also illustrated again in  FIG. 8 , from which it can also be seen that this covering cloth, which covers the first ventilation opening  30 , is sewn by means of preferably only one fastening seam  37  to the second side wall  24 . The advantage of such a covering cloth  36  is in particular that the first ventilation opening is also reliably closed when it strikes onto the vehicle door precisely in the region of the door shoulder, i.e. “on the edge”. In this case, without such a covering cloth, a “half open” state occurs which is difficult to define. 
       FIG. 7  shows a vehicle seat  10  with a side airbag  20  in a side view. It can be seen from this figure that the first ventilation opening  30  can also be embodied as a field  32  of single openings with several rows, in the example embodiment shown with three rows  34   a ,  34   b , and  34   c . The height of this field  32  of single openings corresponds preferably substantially to the height adjustability of the vehicle seat. The dot-and-dash lines in  FIG. 7  show here the relative position of the door shoulder  47  in the uppermost and lowermost adjustment of the vehicle seat  10 . Through such an arrangement, a very fine tuning of the airbag hardness is obtained as a function of the vertical position of the vehicle seat and therefore also as a function of the size of the vehicle occupant. The desired effect of a finer graduation, compared with a sole single opening forming the ventilation opening, can also already be achieved by two single openings which are arranged substantially on top of one another. However, a field of single openings improves both the fineness of the graduation and also the reproducibility. 
     The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.