Abstract:
An airbag arrangement for a vehicle occupant restraining system including at least one inflatable airbag and an inflating device. The airbag includes a first inflatable area which extends in the inflated status of the airbag in the area of a first body region of the vehicle occupant, and a second inflatable area, which extends in the inflated status of the airbag in the area of a second body region of the vehicle occupant. The first inflatable area has a larger thickness vertical to the main extension plane of the airbag than the second inflatable area. The inflating device and the airbag are designed for inflating the first inflatable area of the airbag to such a high internal pressure that during the impact of the occupant on the airbag a force is exerted onto the first body region of the vehicle occupant which sets the occupant into a tilting motion.

Description:
BACKGROUND 
     The present application relates to an airbag arrangement for a vehicle occupant restraining system and a method for protecting a vehicle occupant. 
     Such an airbag is for instance known from DE 10 2004 009 013 A1 (incorporated by reference herein). 
     SUMMARY 
     The problem to be solved by at least one disclosed embodiment is to provide an airbag arrangement which keeps the stress of the vehicle occupant to be protected as low as possible. 
     According to an exemplary disclosed embodiment, an airbag arrangement for a vehicle occupant restraining system is provided with
         at least one inflatable airbag for the protection of the vehicle occupant; and   an inflating device for inflating the airbag, whereby the airbag is provided with:   a first inflatable area which extends in the inflated status of the airbag in the area of a first body region of the vehicle occupant, and   a second inflatable area which extends in the inflated status of the airbag in the area of a second body region of the vehicle occupant which is being less resilient than the first body region, whereby   the first inflatable area has in the inflated status of the airbag a larger thickness vertical to the main extension plane of the airbag than the second inflatable area, and whereby   the inflating device and the airbag are designed for inflating the first inflatable area of the airbag to such a high internal pressure so that during the impact of the vehicle occupant on the airbag a force is exerted onto the first body region of the vehicle occupant which sets the vehicle occupant into a tilting motion.       

     The airbag arrangement according to the exemplary embodiment is in particular about a side airbag arrangement which is to be arranged for instance in or on a vehicle seat or a vehicle door. The airbag arrangement is for instance to be arranged in a vehicle such that the main extension plane, e.g. the plane along which the inflatable airbag mainly extends, is spanned by the vehicle longitudinal and the vehicle height direction. 
     Since the first inflatable area has vertical to the main extension plane of the airbag, e.g. in case of an airbag assembled in the vehicle for instance in vehicle cross direction, a larger thickness (extension) than the first inflatable area which is arranged to a less resilient body region of the vehicle occupant to be protected, the first area of the airbag docks in the event of a crash onto the vehicle occupant. 
     A docking of the second inflatable area onto the second body region of the vehicle occupant occurs therefore—if at all—to a later time point at a later time after contact of the first area to the body region of the vehicle occupant arranged to the first area. Hereby, the movement of the vehicle occupant can be decelerated (in particular due to dissipation of movement energy) for instance before the impact of the sensitive second body region of the vehicle occupant onto the airbag. 
     Since the first inflatable area of the airbag is inflated in case of a crash to a high internal pressure in particular in comparison to the common side airbags, a “penetrating” of the vehicle occupant through the first inflatable area is avoided so that the more sensitive body region of the vehicle occupant strikes only with the desired timely delay or not at all on to the airbag. A force is exerted in particular at first only to the body region of the vehicle occupant striking the first area. This means that at first only the movement of the body region arranged to the first area of the airbag is delayed during impact onto the airbag while other body regions of the vehicle occupant move due to their inertia further into the direction of the airbag so that the tilting motion of the vehicle occupant is generated. 
     The generated tilting motion of the vehicle occupant leads in particular to the case that the vehicle occupant strikes the airbag virtually bevelled whereby in particular in a first striking phase at first only an upper body region (for instance upper thorax area, shoulder area) and a lower body region (for instance pelvis) of the vehicle occupant comes in contact with the airbag and a middle region located between (in particular the thorax area or a lower thorax area) docks only with the delay or not at all to the airbag. 
     The first body region of the vehicle occupant is moved away in particular by a stimulating effect of the first inflatable area of the airbag from a collision side of the vehicle, for instance into the vehicle interior, or at least a movement of the first body region to the vehicle structure effected by the collision is decelerated. 
     It is being pointed out that the formulation whereby the “first area” has a larger thickness than “the second area” is not necessarily to be understood that the first and/or the second area have to have a constant thickness, e.g. a constant extension vertical to the main extension plane of the airbag. The “thickness” of the first and/or the second area relates in particular to an average thickness of the respective area. 
     In an exemplary embodiment, the airbag arrangement is concerned with the side airbag arrangement which is to be arranged in the vehicle such that the first inflatable area of the airbag has in the inflated status of the airbag in vehicle cross direction a larger thickness than the second inflatable area so that the vehicle occupant during striking the airbag is set into a tilting motion around an axis continuing essentially parallel to the vehicle longitudinal direction. 
     In a further exemplary variant, the inflating device and the airbag are designed for inflating the first area of the airbag to an internal pressure of at least ca. 1.5 bar. The first area of the airbag is inflated for instance to an internal pressure between 1.5 and 2.5 bar, in particular ca. 1.8 bar. This pressure is for instance considerably higher than the internal pressure usually applied in a side airbag. 
     The mentioned high internal pressure is generated in particular only in the first area of the airbag, which is arranged to a specifically resilient body region of the vehicle occupant, in order to avoid the impact of the second, less resilient body region onto the airbag or at least to temporarily delay it. The second area of the airbag has for instance in the inflated status a lower internal pressure than the first area of the airbag. It is however also possible that the first and the second area have similar internal pressures in the inflated status. 
     The first and the second inflatable area of the airbag can be for instance formed as sections of a common inflatable chamber of the airbag whereby the inflatable chamber is in particular defined by an (one or multiple layers) airbag material. In a further variant the first and the second area of the airbag are formed in each case by inflatable chambers being at least sectionally separated from each other. In this variant the chambers can be in fluid communication with each other or can also be completely separated from each other. 
     In another exemplary embodiment, the airbag comprises a third inflatable area for protection of a third (being different from the first and the second body region of the vehicle occupant) body region of the vehicle occupant. The airbag is for instance designed such that the vehicle occupant while striking the airbag is set in such a tilting motion that the third body region strikes the third area of the airbag before the second, less resilient body region strikes the second area of the airbag. 
     The second area of the airbag is for instance—in respect to the assembled and inflated status of the airbag—arranged along the vehicle height direction between the first and the third area. 
     In an exemplary embodiment the third inflatable area of the airbag is provided with damping means (for instance in form of one or multiple outflow openings through which gas can disappear during the impact of the vehicle occupant) so that kinetic energy of the vehicle occupant and/or of a vehicle structure moving towards the airbag following the collision is dissipated. 
     Furthermore, the third area of the airbag can have crosswise to the main extension direction of the inflated airbag (e.g. in respect to the in the vehicle assembled and inflated status of the airbag along the vehicle cross direction) a larger thickness (extension) as the second area of the airbag. The third area has for instance a similar thickness than the first area of the airbag. The third area is in particular designed such that it is inflated with an internal pressure comparable to the first inflatable area or is inflated with a lower internal pressure. 
     The third area serves in particular the protection of an upper thorax region, a shoulder and/or head region of the vehicle occupant. It can be provided simultaneously that the first inflatable area of the airbag is designed for the protection of the pelvis region and the second inflatable area of the airbag is designed for the protection of the thorax region (in particular a lower thorax region) of the vehicle occupant. 
     In this example the vehicle occupant will strike the first area of the airbag after a collision of the vehicle at first with the pelvis region whereby the pelvis area is decelerated in its movement to the collision side or is moved into the vehicle interior. Hereby the impact of the thorax region of the vehicle occupant onto the second area of the airbag is delayed or even avoided. Furthermore, due to the striking of the vehicle occupant in its pelvis area a tilting motion of the vehicle occupant is initiated so that the upper body area (in particular the shoulder and head region) of the vehicle occupant is moved towards the airbag and couples to the third inflatable area of the airbag with a timely delay. 
     Furthermore, the third area of the airbag provided for the protection of the shoulder region of the vehicle occupant can have damping means for damping the impact, for instance in the form of an outflow opening, so that due to the impact of the shoulder region of the vehicle occupant onto the third area of the airbag the kinetic energy of the vehicle occupant can be absorbed or dissipated. Due to the impact of the shoulder region onto the airbag so much energy can in particular be absorbed or dissipated so that in case of a possible following impact of the thorax region of the vehicle occupant onto the airbag said region is only affected to a small extent. 
     In order to produce the lower thickness of the second inflatable area of the airbag means are in particular provided via which the at least two sections of an inner surface of an airbag material facing the interior of the second inflatable area, which defines the second inflatable area, are connected with each other. The second inflatable area is for instance formed by two airbag layers connected to each other along a rim seam whereby the means for reduction of thickness comprise at least one dart via which the two airbag layers are additionally connected to each other. In a further variant the means for reduction of thickness comprises an adhesion and/or a retaining strip arranged in the interior of the second inflatable area. 
     The airbag is for instance provided with a bevel on its side pointing in the inflated status in forward travelling direction in order to adapt in the inflated status to an arm outline and/or lateral shoulder outline of the vehicle occupant. 
     In a further exemplary embodiment, the airbag arrangement is assembled to a vehicle seat whereby the airbag is designed such that it is in the inflated status along a back rest of the vehicle seat shorter than the back rest. The airbag is in particular designed such that it ends in the inflated status beneath a beginning of an arm of the vehicle occupant sitting on the vehicle seat. 
     The present application also discloses a method for protecting a vehicle occupant with the steps
         arranging an airbag arrangement with at least one inflatable airbag for protecting the vehicle occupant which   is provided with a first inflatable area for protecting a first body region of the vehicle occupant and a second inflatable area for protecting a second body region of the vehicle occupant which is less resilient than the first body region, whereby   the airbag is designed and the airbag arrangement is arranged in the vehicle such that the first inflatable area has an inflated status of the airbag in vehicle cross direction, a larger thickness than the second inflatable area; and   inflating the first inflatable area in case of a collision of the vehicle to such a high internal pressure that during impact of the vehicle occupant on the airbag a force is exerted to the first body region of the vehicle occupant which sets the vehicle occupant into a tilting motion.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention is explained in the following by the means of examples referring to the Figures. 
         FIG. 1A  shows an airbag of an airbag arrangement according to a first embodiment. 
         FIG. 1B  shows the airbag according to  FIG. 1A  from the vehicle front. 
         FIG. 2A  shows an airbag according to a second embodiment of the airbag arrangement. 
         FIG. 2B  shows an airbag according to a third embodiment of the airbag arrangement. 
         FIG. 2C  shows a front view of the airbags shown in the  FIGS. 2A and 2B . 
         FIG. 3A  shows an airbag according to a fourth embodiment of the airbag arrangement. 
         FIG. 3B  shows an airbag according to a fifth embodiment of the airbag arrangement. 
         FIG. 3C  shows a side view of the airbags shown in the  FIGS. 3A and 3B . 
         FIG. 4A  shows an airbag according to the sixth embodiment of the airbag arrangement. 
         FIG. 4C  schematically shows the airbag of  FIG. 4A  as compared with a seat back of the vehicle seat. 
         FIG. 5A  shows an airbag according to a seventh embodiment of the arrangement. 
         FIG. 5C  schematically shows a front view of the airbag shown in the  FIGS. 5A and 5B . 
     
    
    
     DETAILED DESCRIPTION 
       FIGS. 1A and 1B  relate to an airbag according to a first embodiment of the airbag arrangement, whereby  FIG. 1A  shows the schematically shown airbag  1  in a side view (in relation to its assembled position in the vehicle from a vehicle long side) and  FIG. 1B  shows the airbag from the front, that means from the vehicle front. 
     Airbag  1  has a first inflatable area  11  for protecting a first body region of the vehicle occupant (not shown) as well as a second inflatable area  12  for protecting a second body region of the vehicle occupant, which is less resilient than the first body region. The second inflatable area  12  extends in the assembled and inflated airbag above (in respect to the vehicle height direction) and adjacent to the first inflatable area  11 . 
     The upper, second inflatable area  12  of the airbag  1  continues in the inflated status of the airbag in particular in the area of a thorax region of the vehicle occupant. The lower, first inflatable area  11  continues on the other hand for instance in the area of the pelvis of the vehicle occupant. The second inflatable area  12  has, if looked at along the vehicle cross direction, a lower thickness B 2  than the first inflatable area  11  (thickness B 1 ). 
     The first area  11  is inflated by an inflating device (not shown) of the airbag arrangement with such a high internal pressure that the pelvis region of the vehicle occupant impacting the first area  11  or being stroked such that it changes its position compared to the upper body region (thorax region), whereby a tilting motion of the vehicle occupant is generated. 
     For reduction of thickness of the second area  12  a multitude of linear darts  15  is provided which connects opposite sections of an airbag material forming the airbag with each other. 
       FIGS. 2A to 2C  relate to a second and third embodiment of an airbag of the airbag arrangement.  FIG. 2C  shows a front view of the airbags  1  shown in the  FIGS. 2A and 2B  in a side view. 
     The airbag of  FIG. 2A  resembles the airbag of  FIG. 1A  since it also has a first and a second chamber  11 ,  12  whereby the second chamber  12  is arranged above the first chamber and has a thickness reduced by darts  15  compared to the lower chamber  11 . In difference to  FIG. 1A  the airbag of  FIG. 2A  has an almost symmetrical outline in its side view, that means a maximum extension—if looked at in forward travelling direction—of the upper chamber corresponds in particular to the one of the lower chamber. The upper area  12  has therefore approximately the same volume as the lower area  11  of the airbag. 
     The outline of the airbag  1  according to  FIG. 2B  corresponds in a side view to the one of the airbag of  FIG. 2A . However, the upper, second area  12  of the airbag has no darts for reducing thickness but a through opening  16  which is surrounded by a circular airbag section  13 . The circular section  13  can have a thickness reduced compared to the lower, first area  11  of the airbag (as shown in  FIG. 2C ). The section  13  can however also have a similar thickness as the area  11  so that the thickness reduction in the upper area of the airbag  12  is only realized by the through opening  16 . Instead of the through opening  16  a fabric layer can for instance be arranged. 
     The variants of the  FIGS. 3A and 3B  ( FIG. 3C  shows a side view of these Figures) resemble the variants of the  FIGS. 2A ,  2 B with the difference that in addition to the first and the second area  11 ,  12  a third area  14  of the airbag is provided, which extends above and subsequently on the second area  12  of the airbag (in respect to the inflated status of the airbag). The third area  14  extends in particular in the area of an upper thorax and/or a shoulder region of a vehicle occupant. 
     According to  FIG. 3C  the third area  14  has a thickness B 3  vertical to the main extension direction of the airbag  1  which is larger than the thickness B 2  of the second area  12  and corresponds approximately to the width B 1  of the first inflatable area  11 . 
     The third inflatable area  14  can extend upwards so far that it protects beside the shoulder region also a head area of the vehicle occupant. In a further variant the airbag has an additional area (not shown) above the third area for protecting the head. 
     It is pointed out that the invention is of course not restricted to the case that only one area of the airbag has a lower thickness. For instance also multiple areas of the airbag can be provided with means for reduction of the width, that means multiple thinner areas are formed whereby the thinner areas can also be produced in different manners, for instance one area has a dart and another area has a through opening. 
       FIGS. 4A and 4B  relate to a further embodiment of an airbag of the airbag arrangement. The airbag  1  is arranged on a vehicle seat (not shown) on which the vehicle occupant  3  is located and has (as recognizable in the front view according to  FIG. 4B ) similar to the airbag of the  FIGS. 1A and 1B  a first (lower) inflatable area  11  above which a second inflatable area  12  is attached. 
     The lower area  11  extends on the level of a pelvis of the vehicle occupant  3  while the upper area  12  of the airbag  1  extends on the level of a thorax area of the vehicle occupant. The height of the airbag  1  along the not shown back rest of the vehicle seat is dimensioned such that the upper area  12  ends approximately beneath a beginning of an arm  31  of the vehicle occupant. Furthermore, the airbag has in the upper area  12  a bevel  121  so that the airbag—if looked at from the side—has an outline which shall extend in the upper area  12  along an arm  32  of the vehicle occupant. The bevel  121  reduces therefore the extension of the airbag  1  in vehicle travelling direction to the beginning of the arm  31 . 
     The lower area  11  of the airbag  1  is filled in case of a crash with such an internal pressure that the pelvis region of the vehicle occupant  3  is moved in contrast to the thorax and shoulder region of the vehicle occupant so that a tilting motion is generated, which leads to the fact that the vehicle occupant after striking the lower area  11  of the airbag with its pelvis region subsequently strikes an upper section of a second area  12  with a section of the upper thorax region or the lower shoulder region. In other words, the vehicle occupant strikes the airbag angular by a tilting motion so that at least the lower and middle section of the thorax region of the vehicle occupant comes in contact with the airbag  1  at last or not at all. 
       FIG. 4C  shows the airbag of  FIG. 4A  in which the airbag arrangement is assembled to a vehicle seat whereby the airbag is designed such that it is, in the inflated status along a back rest  17  of the vehicle seat, shorter than the back rest  17 . The airbag is in particular designed such that it ends in the inflated status beneath a beginning of an arm  31  of the vehicle occupant  3  sitting on the vehicle seat. 
       FIGS. 5A and 5B  relate to a modification of the embodiment of  FIGS. 4A and 4B . A singular airbag  1  has beside the first and second area  11 ,  12  a third area  14  which extends on the level of the shoulder region of the vehicle of the vehicle occupant  3 . Due to the tilting motion of the vehicle occupant induced by the impact of the vehicle occupant  3  onto the airbag  1  the shoulder region strikes the airbag in the area of the third area  14  after the pelvis region of the vehicle occupant. A thinner second area  12  of the airbag comes therefore in contact with the thorax region of the vehicle occupant  3  only late or not at all. 
     The airbag  1  has again a bevel  121  so that its lateral outline is adapted to the arm  32  of the vehicle occupant  3 . The airbag has, in particular in the vehicle longitudinal direction, in the first area  11  a first extension, in the second area a second extension and in the third area  14  a third extension, whereby the extension decreases from the lower first area  11  to the upper third area  14  so that the bevelled front side  121  is generated. The vehicle occupant  3  strikes thereby the airbag such that the arm  32  does not couple at all or only with a section to the airbag  1 , whereby the strain, in particular of the thorax region of the vehicle occupant, is further reduced. 
     As shown in  FIG. 5B  the upper inflatable area  14  can in particular be designed such that it wraps with a section around the shoulder of the vehicle occupant  3 , if he strikes the airbag  1 . Therefore, the upper section  14  extends in part between a back rest  5  of the vehicle seat and the shoulder region of the vehicle occupant. 
       FIG. 5C  shows a front view of the airbag shown in  FIGS. 5A and 5B . The third area  14  of the airbag  1  can have crosswise to the main extension direction of the inflated airbag (e.g. in respect to the in the vehicle assembled and inflated status of the airbag along the vehicle cross direction) a larger thickness (extension) as the second area  12  of the airbag  1 . The third area  14  has for instance a similar thickness than the first area  11  of the airbag. The third area  14  is in particular designed such that it is inflated with an internal pressure comparable to the first inflatable area  11  or is inflated with a lower internal pressure. Furthermore, the third area  14  provided for the protection of the shoulder region of the vehicle occupant can have damping means for damping the impact, for instance in form of an outflow opening  141 , so that due to the impact of the shoulder region of the vehicle occupant onto the third area  14  of the airbag the kinetic energy of the vehicle occupant can be absorbed or dissipated. Due to the impact of the shoulder region onto the airbag so much energy can in particular be absorbed or dissipated so that in case of a possible following impact of the thorax region of the vehicle occupant onto the airbag said region is only affected to a small extent. 
     German Priority Application 20 2008 016 777.9, filed Dec. 18, 2008 and German Priority Application 10 2009 007 179.2, filed Jan. 28, 2009, including the specification, drawings, claims and abstract, are incorporated herein by reference in their entireties.