Abstract:
In an airbag module arrangement, an airbag module is arranged on a vehicle component, in particular a seatback, the airbag module including an airbag carrier, an airbag and a gas generator, which are jointly attached to a support structure in an installation space of the vehicle component, from which the airbag exits in the event of a triggering and subsequently opens at least one material layer situated over the airbag module and inflates in a passenger compartment, etc. 
     There is a provision for the installation space of the airbag module to be surrounded by a foam part that is closed at least in the direction of inflation, and a fleece-like layer to be situated on the inner side of foam part at least in the desired exit region of the airbag module from the foam part, which has a specifiable perforation in the desired exit region of the airbag module.

Description:
FIELD OF THE INVENTION 
     The present invention relates to the arrangement of a soft cover lateral impact airbag module on a vehicle component, in particular a backrest of a vehicle seat. 
     BACKGROUND INFORMATION 
     In the non-inflated state, airbags must be as small as possible and accommodated securely within the interior equipment of the vehicle, for example in dashboards, impact absorbers or side trim panels as well as in vehicle seats. 
     Today&#39;s vehicles are often equipped with lateral impact airbags, which may have the form of a lateral air curtain situated in a vehicle roof; or, alternatively or additionally, an airbag may be situated within a vehicle seat system. 
     One disadvantage of airbags that are located within a seat system is that the airbags must break through the seat material before they are able to inflate completely so as to protect a vehicle occupant. During the inflation, such an airbag may strike foam or other seat cushion materials and must then break through the seat cover in order to be able to exit the seat system. Here there is a problem of preventing the lateral region from being “shot through” in an uncontrolled manner and of avoiding the creation of individual foam particles when firing the airbag in order to protect the occupants. 
     A disadvantage is the fact that the hard cover structure of the airbag module that is used in most cases forms externally visible elevated upholstery regions after the vehicle seat has been “broken in” because of minimal changes in the foam part, for example in an open foam region developed laterally in the back rest. 
     Aside from the so-called hard cover airbag modules, however, so-called soft cover airbag modules are known as well. 
     The installation in the specified installation spaces is difficult because the task is one of accommodating an airbag that is folded only loosely, while at the same time ensuring a secure inflation. Since the folding of an airbag is important with regard to the type and reliability as well as the speed of inflation, the folded airbag is held by retaining straps or a so-called soft cover in the folded position during transport and installation until inflation occurs by the gas of a gas generator. 
     SUMMARY 
     Example embodiments of the present invention provide an arrangement of a soft cover airbag module that avoids the mentioned disadvantages and overcomes the mentioned difficulties. 
     Example embodiments of the present invention accommodate a soft cover airbag module in a vehicle seat such that no visible regions are formed by the airbag module during the lifetime of the vehicle seat through changes to the seat from outside and that additionally a reliable inflation and exit of the airbag is ensured. 
     Example embodiments of the present invention provide that an installation space of the airbag module in a vehicle component, in particular a back rest, is surrounded by at least one material layer comprising a foam part and a fleece layer, the foam part being closed at least in the direction of inflation and the fleece-like layer being situated at least in the desired exit region of the airbag module from the foam part on the inner side of the foam part, which has a specifiable perforation in the desired exit region of the airbag module. 
     The airbag module may include a soft cover lateral impact airbag module, the airbag of which is fastened on the airbag carrier by a retaining strap, etc., and is kept in an installation space provided in the foam part. 
     The perforation may be implemented on the inner side of the fleece-like layer in the direction toward the airbag module. 
     The fleece-like layer may be already foamed onto the foam part when foaming the foam part in a foam part tool. 
     In an exemplary embodiment of a vehicle seat, the perforation of the fleece-like layer is implemented as extending substantially in the z direction substantially orthogonally to the inflation direction of the airbag of the airbag module. 
     The perforation of the fleece-like layer achieves a specific tearing of the back rest foam in the event that the lateral impact airbag is triggered. 
     The perforation of the fleece-like layer may be slotted, hole-perforated, etc. The slotting or hole-perforation of the fleece-like layer is performed according to a specifiable slot or hole pattern. The fleece-like layer yields the advantage that the fleece-like layer firmly holds the foam of the foam part together in the exit region of the airbag of the airbag module, while preventing the formation of individual foam particles of the foam. 
     A slot or hole pattern may be formed, in which the length of the slotted or hole-perforated regions of the fleece-like layer increases from top to bottom in a perforation extending (vertically) in the z direction. 
     Furthermore, a slot or hole pattern may be formed, in which the spaces between the slotted or hole-perforated regions of the fleece-like layer decrease from top to bottom in a perforation extending (vertically) in the z direction. The foam part may also have a slotted or pre-slotted segment on the inner side in the direction of the airbag module, the position of the slotted or pre-slotted segment being adjusted to or corresponding to the perforation of the fleece-like layer. 
     The foam part may additionally be provided with a foam groove on the inner side of the foam part, which allows for a defined tearing of the foam part when the airbag of the airbag module exits in a specifiable direction. 
     The foam groove may be introduced on the inner side into the foam part in a crescent-like shape and oriented in the specifiable direction, depending on the desired direction of inflation. For protecting a vehicle occupant laterally, in particular for protecting the hip region of an occupant, an inflation direction at an angle forward between the x, y directions is desired for example, the foam groove furthermore being introduced, e.g., extending at an angle across from an imaginary y plane. To allow for this direction of inflation, the foam groove is introduced in accordance with these specifications, as the figures additionally illustrate and as the subsequent exemplary embodiment describes in more detail. 
     A cover surrounding the foam part may have a weakening, the position of the weakening being adjusted to or corresponding to the perforation of the fleece-like layer. 
     Finally, the perforation may be implemented in the transition region of the foam part as extending substantially in the z direction from a planar inner contour extending substantially in the x direction to the planar inner contour of the foam part extending substantially in the y direction such that a direction of inflation develops at an angle forward substantially in the x direction between the x, y directions for the lateral protection of a vehicle occupant. 
     Example embodiments of the present invention are explained in more detail below with reference to the appended figures. The present invention is not limited to the exemplary embodiment. Explicit reference is made to the fact that a use is possible in any region of a vehicle seat or other regions of the vehicle, for example in a dashboard, etc., even if the subsequent description only refers to an airbag module arrangement as a lateral impact module in a backrest. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a lateral view of a support structure supporting a soft cover airbag module in the example of a backrest. 
         FIG. 2  is a front external view of the backrest having a laterally disposed airbag module arrangement. 
         FIG. 3A  is a perspective rear view into the open foam part of a backrest with the soft cover airbag module pulled out. 
         FIG. 3B  illustrates the associated support structure of the backrest. 
         FIG. 4  is a schematic perspective view of an open backrest at an angle from the rear with an indication of a sectional line A-A through the foam part of the backrest. 
         FIG. 5  is a schematic perspective view of a closed backrest at an angle from the rear with an indication of the sectional line A-A through the foam part of the backrest. 
         FIG. 6A  illustrates section A-A from  FIG. 4  or  5  of the foam part having a fleece-like layer situated on it. 
         FIG. 6B  is an enlarged view of  FIG. 6A  of the lower region of section A-A from  FIG. 4  or  5  of the foam part. 
         FIG. 7  is a schematic perspective view of an open backrest at an angle from the rear including a representation of the perforation of the fleece-like layer. 
         FIGS. 8A ,  8 B are views of an open backrest at an angle from the rear, in which the arrangement of a foam groove on the inside of the foam part is visible. 
         FIGS. 9A ,  9 B illustrate a section B-B from  FIGS. 8A and 8B  through the foam part for representing the position and shape of the foam groove in the foam part. 
     
    
    
     DETAILED DESCRIPTION 
       FIG. 1  shows a lateral view of a support structure  12  supporting a soft cover airbag module  22  in the example of a backrest  10 . Backrest  10  is the vehicle component with reference to which example embodiments of the present invention are to be explained in greater detail. 
       FIG. 1  shows a soft cover airbag module in the embodiment as a soft cover airbag lateral module  22  in two designs: one design according to the soft cover airbag lateral module  22 - 1  variant and another design according to the soft cover airbag lateral module  22 - 2  variant. In the second variant, the soft cover airbag lateral module is drawn out further downward by an extended component. Soft cover airbag lateral modules  22  are connected to support structure  12  of the backrest via a fastening device  24 . To show the relative size, an opening  28  is visible in the support structure  12  of the backrest, in which an operating element for a lumbar adjustment device  26  is situated. Soft cover airbag lateral module  22  substantially covers a central third in relation to the length of backrest  10 . 
     The front external view of the backrest in  FIG. 2  shows that the soft cover airbag lateral module is situated between support structure  12  and the foam of a backrest cushion. The operating element of lumbar adjustment device  26  is flush with the lower region of soft cover airbag lateral module  22 - 1 / 22 - 2 . 
     In a perspective rear view,  FIG. 3  shows an open foam part  14 , which surrounds support structure  12  of backrest  10 , soft cover airbag lateral module  22  being shown in a pulled-out state. An installation space  16  is provided in foam part  14  in this region of foam part  14 .  FIG. 3A  additionally shows opening  28  provided for an operating element of lumbar adjustment device  26 , which is shown in  FIG. 3B  as being fastened in support structure  12  of backrest  10 . 
       FIG. 4  shows installation space  16  in open backrest  10  in a schematic perspective view at an angle from the rear. The position of sectional line A-A through foam part  14  of backrest  10  is likewise indicated, section A-A being shown in detail in  FIGS. 6A ,  6 B. 
       FIGS. 4 and 6B  in particular show the installation space requirement  16  of soft cover airbag lateral module  22  in foam part  14 . 
     The position of sectional line A-A is likewise shown in  FIG. 5 , a backrest  10  being shown here in a perspective view of a closed backrest  10  at an angle from the rear. This external view shows that foam part  14  of backrest  10  is surrounded by a cover  18 , which has a weakening  20  in the region of soft cover airbag lateral module  22 . 
     Corresponding to this weakening  20  or at least matched in its position, foam part  14  has a perforation  32 , which is not introduced into foam part  14  itself however, but is rather introduced into a fleece or a fleece-like layer  30 . Fleece-like layer  30  may be foamed on or applied in another manner on foam part  14 , for example by bonding, etc. 
     As  FIGS. 6A and 6B  show in section A-A, the fleece or fleece-like layer  30  is situated on the backside of the foam part. It is possible to situate the fleece or fleece-like layer  30  on the entire rear area of foam part  14  or to provide it only partially in the region of soft cover airbag lateral module  22  on the lateral inner side of foam part  14 . 
     What is shown is the full-surface arrangement on the backside of foam part  14 , it being possible for the fleece or fleece-like layer  30  to be introduced into the foaming tool already during the foaming of foam part  14  such that a compact foam part having a mounted fleece  14 ,  30  is obtained. Preferably, the fleece or fleece-like layer  30  is perforated already prior to foaming. 
     The pattern of the perforation may be gathered especially from  FIGS. 6A ,  6 B and  FIG. 7 . 
     Moreover, perforation  32  may be provided in the transition region of foam part  14  from an inner contour extending substantially in the x direction to an inner contour of foam part  14  extending substantially in the y direction such that a direction of inflation  36  is directed at an angle forward in the x direction between the x, y directions for the lateral protection of a vehicle occupant. Other directions of inflation  36  are possible. 
       FIGS. 6A ,  6 B in combination with  FIG. 5  show that weakening  20 , extending for example through an airbag seam in cover  18  likewise in the z direction, in this exemplary embodiment extends substantially in the front region of the lateral part of backrest  10 , in which perforation  32  of the fleece or fleece-like layer  30  is provided as well on the inner side of foam part  14 . 
     This approach allows for the airbag of soft cover airbag lateral module  22  to shoot through while preventing as much as possible foam particles from forming when the airbag is fired. The foam particles, which could possibly still detach from foam  14 , are advantageously bound by the fleece or fleece-like layer  30 . 
       FIG. 7  shows a schematic perspective view of an open backrest  10  at an angle from the rear including a view of perforation  32  of fleece-like layer  30  itself. It is disposed for example in the position described in  FIGS. 6A and 6B  and is implemented in Figure as perforation  32  in the manner of a slotted segment  34 . All possible shapes and designs of perforations  32  are theoretically possible. 
     Thus, a precisely prescribed number of slots  34 A,  34 B is introduced, which were previously laid out in a kind of slot or hole pattern with respect to a specific distance  38  to one another and respectively having a predetermined length. 
     An example embodiment is explained in greater detail in exemplary fashion with reference to  FIG. 7 . 
     A slot or hole pattern is formed in which the length of the slotted or hole-perforated regions of fleece-like layer  30  increases from top to bottom in a perforation  32  extending (vertically) in the z direction. By contrast, distances  38  between the slotted or hole-perforated regions of fleece-like layer  30  decrease from top to bottom in a perforation  32  extending (vertically) in the z direction. 
     This ensures safe tearing properties of foam part  14 , and, in the event of a triggering, fleece-like layer  30  substantially prevents the creation of individual foam particles. 
     The length of the short slots  34 A or short hole-perforations of the slotted or hole-perforated regions in the upper region of fleece-like layer  30  may be, e.g., between 10 and 30 mm and the length of the long slots  34 A or the long hole-perforations in the lower region of fleece-like layer  30  may be, e.g., between 30 and 50 mm. 
     The distance  38  between the slotted or hole-perforated regions of fleece-like layer  30  is, e.g., between 2 and 15 mm and decreases from top to bottom. 
     The foam part  14  may have a slotted or pre-slotted segment, the position of the slotted or pre-slotted segment being adjusted to or corresponding to perforation  32  of fleece-like layer  30  such that the above description and layout also applies to a slotting or perforation of foam part  14 . 
     Individually and in combination, these measures have the effect that the airbag module exits from bottom to top since in the lower region, which represents approximately ⅔ of the total length, the longer slots  34 B or hole-perforations are implemented at smaller distances  38 . In the upper region, which represents approximately ⅓ of the total length of slotted segment  34  or hole-perforation, slots  34 A are shorter and distances  38  are greater. 
     The length of slots  34  increases from top to bottom not necessarily linearly or distances  38  decrease non-linearly. A smaller length increase of the slotting or hole-perforation may be preferred in the upper region and a greater reduction of distances  38  in the upper region of the slotting or hole-perforation. 
     That is to say, in, e.g., the lower ⅔ region of the slotted segment or hole-perforation the length of the slots or hole-perforations increases to a greater degree and the distances  38  between the slots or hole-perforations decrease only a little in the lower ⅔ region. 
     Notwithstanding the resulting already very good and safe tearing properties of foam part  14 , it is additionally possible to configure a foam groove  14 A from the inner side of foam part  14  in foam part  14  without the formation of individual foam particles in the event of triggering. This foam groove  14 A is shown in more detail in  FIGS. 8A ,  8 B,  9 A and  9 B and produces in the location in which it is introduced an additional starting point or weakening point for a well-aimed tearing by the airbag of airbag module  22  at a specified location or in a specified region of seatback  10 . 
     Foam groove  14 A is introduced in a crescent-like manner into foam part  14  and is arranged or oriented in a specifiable direction, depending on the desired direction of inflation  36  in particular for the lateral protection of a vehicle occupant, in the direction of a hip region substantially at an angle toward the front in the x direction between the x, y directions. 
       FIG. 8A  shows in detail Z the region of seatback  10 , which is shown in an enlarged view in  FIG. 8A . 
       FIG. 8B  shows the position of foam groove  14 A in foam part  14  in the view from the rear onto foam part  14  with a view into an open seatback  10 . Foam groove  14 A may be disposed in a specifiable position. In the exemplary embodiment, it is disposed extending at an angle across from an imaginary y plane. This arrangement ensures a tearing point with respect to the imaginary y plane in the z direction in the outer region of seatback  10  that is higher than a lower tearing point in the region of seatback  10  located further inward. 
       FIG. 9A  indicates the development of foam groove  14 A on the basis of sectional line B-B, which follows the position of the angularly arranged foam groove  14 A, and the associated sectional view from  FIG. 9B . As shown in  FIG. 9B , this represents a crescent-like notch/recess  40  in the region of foam part  14 . The groove height h is approximately 1.8 mm for example and, depending on the foam thickness of foam part  14 , may of course also be introduced into foam part  14 , as required, in a thicker or thinner or deeper or less deep fashion. 
     List of Reference Characters 
     
         
           10  vehicle component (seatback) 
           12  support structure (seatback frame) 
           14  foam part (seatback foam part) 
           14 A foam groove 
           16  installation space 
           18  cover 
           20  weakening 
           22  lateral impact airbag module (soft cover) 
           22 - 1  first embodiment variant of  22   
           22 - 2  second embodiment variant of  22   
           24  fastening device 
           26  lumbar adjustment device 
           28  opening for operating element of lumbar adjustment device 
           30  fleece 
           32  perforation 
           34  slotted segment 
           34 A short slot 
           34 B long slot 
           36  direction of inflation of airbag of airbag module 
           38  distance 
           40  notch/recess 
         h height of foam groove