Abstract:
A moveable integrated airbag panel and method of assembly is presented. In the exemplary application, a vehicular expandable airbag is attached to the inside of an A-pillar trim panel along with the inflator to form an integrated airbag panel that is attached as a preassembled unit to the vehicle body structure. On deployment of the airbag, the integrated airbag panel as a unit moves away from the A-pillar structure while a portion of the airbag remains attached to the A-pillar structure to limit movement of the airbag. The moveable integrated airbag panel provides increased coverage and protection of the occupant in the A-pillar area.

Description:
FIELD OF INVENTION 
       [0001]    This invention generally pertains to the field of supplemental restraint systems for passenger vehicles and more particularly to safety airbags. 
       BACKGROUND 
       [0002]    Protective airbag restraints for use in passenger automobile applications have become standard equipment on almost all new vehicles sold in the United States and are common equipment on vehicles manufactured and sold throughout the world. In recent years, side or frontal airbags have been employed to further protect occupants in frontal and side vehicular impact events. 
         [0003]    An important and difficult area to protect is the area of the A-pillar vehicle body structure which is the narrow sheet metal body structure positioned between the front door window glass and the windshield. In vehicular frontal or angular impacts, it is advantageous for occupant safety to provide a cushion or airbag to reduce hard impact of an occupant with this rigid body structure. 
         [0004]    Early airbags positioned in the door or instrument panel areas were rigidly attached to the sheet metal body structure and were deployed either through intentional thin areas or seams molded into the trim panels, or the panels were provided with hinge-like attachments where on inflation of the airbag, the trim panel or portions thereof pivoted out of the way of the expanding airbag. This required special features to be molded into the trim panels and additional assembly steps as the airbag system needed to first be installed to the sheet metal on the vehicle main assembly line, then carefully covered by an interior trim panel to conceal the airbag and provide an aesthetically pleasing surface for the occupant. 
         [0005]    These efforts were only partially successful and added much complexity to the design, manufacture and assembly of the airbag system in the vehicle. These prior airbag systems, particularly in the A-pillar area also suffered disadvantages in completely covering or providing a cushioning surface all along the A-pillar, most particularly in the lower portion of the A-pillar where the trim panel meets the door or instrument panel. This area is particularly difficult to protect smaller occupants, for example individuals in the lower 5 percent of the general population in size. 
         [0006]    It would be advantageous to provide an airbag apparatus and method of manufacture that improved on these deficiencies of prior airbag systems. It would be further advantageous to provide an airbag system that was integrated with the trim panel for ease of manufacturing and assembly and that provided additional coverage and protection of the occupant. 
       SUMMARY OF THE INVENTION 
       [0007]    The present invention provides an integrated airbag panel and a method of assembly therefore. In one example of the invention, a moveable integrated airbag panel is provided. The moveable integrated airbag panel includes an interior A-pillar trim panel with the airbag and the inflator mounted to an interior surface of the trim panel forming an integrated airbag panel, that, as a unit, is releaseably attached to the sheet metal support structure. 
         [0008]    In one example, the airbag and trim panel are attached to the support structure through a first fastener having a frangible portion. On inflation of the airbag, the frangible portion fractures and the integrated airbag panel, as a unit, is forced away from the vehicle sheet metal body structure providing a contact or cushioning surface substantially the entire length of the A-pillar. 
         [0009]    In an alternate example, the first fastener includes a body portion and a clip portion. On inflation of the airbag, the base portion mechanically separates from the clip portion allowing the body portion and the integrated airbag panel to move away from the pillar support structure while the clip portion remains attached to the pillar structure maintaining attachment of the airbag to the pillar structure. In this example, the clip and the airbag serve as a tether to limit movement of the trim panel from the pillar structure. 
         [0010]    In an alternate example, the airbag is connected at additional points to the interior surface of the moveable trim panel in a substantially permanent way by second fasteners to ensure the airbag remains integrated or connected to the trim panel as the trim panel moves away from the body structure on expansion of the airbag. 
         [0011]    In another example of the invention, one or more mounting bases are integrally molded into the trim panel to facilitate attachment of the airbag to the trim panel. 
         [0012]    The method of assembly includes providing a moveable panel and mounting the airbag and inflator to the moveable panel forming an integrated airbag panel. The integrated panel is attached to the vehicle body structure by a first fastener which permits the airbag to expand allowing the integrated airbag panel to move away from the body structure and provide a cushioning surface. 
     
    
     
       DESCRIPTION OF THE DRAWING 
         [0013]    The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: 
           [0014]      FIG. 1  is a schematic perspective view of an example of the integrated airbag panel in the form of a passenger vehicle A-pillar trim panel. 
           [0015]      FIG. 2  is an enlarged cross-sectional view taken along line  2 - 2  in  FIG. 1  showing an airbag in an uninflated state. 
           [0016]      FIG. 3  is an enlarged exploded view of the components depicted in  FIG. 2 . 
           [0017]      FIG. 3A  is a front view of an exemplary aperture in the A-pillar sheet metal. 
           [0018]      FIG. 4  is an enlarged cross-sectional view taken along line  4 - 4  in  FIG. 1 . 
           [0019]      FIG. 5  is an enlarged cross-sectional view taken along line  2 - 2  in  FIG. 1  showing an example of the airbag in an inflated state. 
           [0020]      FIG. 5A  is an enlarged portion of  FIG. 5 . 
           [0021]      FIG. 6  is a schematic rear view of the left hand side of a vehicle A-pillar and an exemplary integrated airbag panel with the airbag in an inflating state. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0022]    An integrated airbag panel and method of assembly is shown in  FIGS. 1-6 . Referring to  FIGS. 1 and 2 , in an exemplary application in the A-pillar portion of a passenger vehicle, an integrated airbag panel  10  includes an interior A-pillar trim panel  12  typically positioned between the windshield  15  and door  17  of a passenger vehicle. Trim panel  12  includes an outer surface  14  positioned facing the interior of a passenger compartment  18  and an interior surface  16  positioned facing the exterior of a vehicle. Trim panel  12  may be an injection molded panel made from polyethylene, polypropylene or other polymers, elastomers, rubbers or other materials, produced by different manufacturing processes, known by those skilled in the art. 
         [0023]    Integrated airbag panel  10  further includes an inflatable airbag  22  which may include a two-layer fabric airbag that is sewn together about a perimeter to form an interior air or gaseous chamber  24  as best seen in  FIG. 5 . Airbag  22  is preferably mounted to the inner surface  16  of trim panel  12  as generally shown in  FIGS. 1 and 2  as more fully described below. Integrated airbag panel  10  further includes an inflator  28  preferably mounted to the inner surface  16  in proximity to airbag  22  as best seen in  FIG. 2 . Airbag  22  is placed in fluid communication with inflator  28  such that on a signal from a controller (not shown) to inflate airbag  22 , compressed air or gas inside of inflator  28  is rapidly forced into airbag  22  to inflate the airbag and provide a cushion between an occupant and the vehicle body structure more filly described below. It is understood that airbag  22  can be a one-piece construction and take different lengths, widths, diameters and shapes than as shown and as known by those skilled in the art. It is further understood that inflator  28  may take many forms to accommodate the particular method used to inflate airbag  22  known by those skilled in the art. 
         [0024]    As best seen in  FIGS. 2 and 3 , in an example of the integrated airbag panel  10 , airbag  22  is mounted to the inner surface  16  of trim panel  12  through use of at least one first fastener  34 . First fastener  34  includes a body portion  54  and an enlarged end  58  positioned axially distant from panel inner surface  16  generally along a longitudinal axis  56 . In a preferred example, body portion  54  is integrally molded into trim panel  12  not requiring a separate mechanical fastener directly attached to trim panel  12 . First fastener  34  may further include an annular clip portion  62  having a first end  64  and an enlarged second end  66 . Clip  62  includes a through-bore  68  which is slightly smaller in diameter than enlarged end  58  so that clip  62  may be inserted over body portion  54  and end  58  in an interference-type fit without overly stressing body portion  54  on installation of clip  62 . It is understood that clip portion  62 , shown as a separate piece, may be integral with body portion  54 . 
         [0025]    In a preferred example of first fastener  34 , body portion  54  includes an elongate frangible portion between the mounting base  70  and enlarged end  58 . As more fully described below, when airbag  22  expands, the frangible portion fractures allowing trim panel  12  to move away from support structure  50 . 
         [0026]    In one example, trim panel  12  may include a first mounting base  70  integrally molded into the inner surface  16  of trim panel  12  including a distal end  72  defining a generally planar surface as best seen in  FIG. 3 . First mounting base  70  projects axially outward along longitudinal axis  56  from inner surface  16  and may include reinforcement ribs  74 . In a preferred example, a second mounting base  80  may be positioned distant from first mounting base  70  as best seen in  FIG. 1  and may be similarly constructed (not shown). 
         [0027]    An aperture  21  though the airbag  22  may be used for insertion of body portion  54  through the aperture for attachment of airbag  22  to trim panel  12 . Aperture  21  is sized smaller than the enlarged second end  66  of clip  62  and enlarged end  58  of frangible portion  54  while still allowing insertion of airbag  22  over them. A washer  46  having a through-bore  48  is similarly placed over enlarged end  58  of frangible portion  54  and enlarged end  66  of clip  62  to further secure airbag  22  to trim panel  12  as best seen in  FIG. 2 . It is understood that other attachments other than integral body portion  54  and washer  46  may be used. For example, instead of body portion  54  being integrally molded into trim panel  12 , a separate mechanical fastener such as a plastic clip having a similar shape as clip  62  may be secured to the interior surface  16  of trim panel  12 . This may be accomplished by many means known by those skilled in the art, for example, through use of mounting pads  88  shown in  FIG. 4  and more fully described below. The fastener or clip first end, for example  64  on clip  62 , would be secured to inner surface  16  and second enlarged end  66  would be positioned through aperture  40  in structure  50  as more fully described below. Other ways of using a first fastener  34  known by those skilled in the art may be used without deviating from the present invention. 
         [0028]    Referring to  FIG. 4 , in an example, airbag  22  may be further secured to trim panel  12  at one or more locations. As best seen in  FIGS. 1 ,  4  and  6 , trim panel  12  may include one or more mounting pads  88  (two shown). Mounting pads  88  are preferably integrally molded into inner surface  16 . A second fastener  84  is inserted through a second airbag aperture  86  and rigidly secured to mounting pad  88 . In a preferred example, second fastener  84  is a permanent mechanical attachment device so that airbag  22  does not separate from trim panel  12  during deployment of airbag  22  as further described below. Second fastener  84  may be robust plastic or aluminum clip or rivet and may include additional mechanical fasteners such as a washer (not shown) or other features known by those skilled in the art. 
         [0029]    On securing airbag  22  and inflator  28  to trim panel  12  as described above, and in other ways known by those skilled in the art, a moveable integrated airbag panel  10  is formed. The integrated airbag panel  10  may be completely assembled off of the vehicle assembly line or at an independent off-site supplier and shipped as a complete one-piece unit into a vehicle assembly plant. The integrated airbag panel  10  is then simply attached to the vehicle body structure as more fully described below. Once the integrated airbag panel  10  is in the vehicle assembly plant, the inflator  28  would be fluidly connected to the airbag  22  and the inflator  28  would be connected to a controller through wires (not shown) at the time the integrated airbag panel  10  is installed in the vehicle. 
         [0030]    Integrated airbag panel  10  following assembly into a complete unit as described, is releaseably attached to vehicle body sheet metal structure  50 , preferably in the A-pillar region of a passenger vehicle. As best seen in  FIGS. 2-4 , in a preferred example, airbag panel  10  is oriented such that at least one first fastener  34  is positioned adjacent body structure sheet metal  50  in substantial axial alignment along longitudinal axis  56  and placed in alignment with aperture  40  in structure  50 . First fastener  34  and more particularly a body portion  54  and enlarged end  58 , along with clip second end  66  are forceably pushed through aperture  40  until end  66  is pushed through in axial locking engagement on the other side of the sheet metal structure  50  as best seen in  FIG. 2 . Although one first fastener  34  may be used to attach airbag panel  10  to support structure  50 , two similarly constructed first fasteners  34  are preferably used (as shown in  FIG. 1 ). Additional fasteners may be used for larger panels. Once integrated airbag panel  10  is installed and properly connected to a controller to monitor impact events, the integrated airbag panel  10  is ready for use to shield and protect occupants. 
         [0031]    In a preferred example, once clip  62  is pushed through structure  50  aperture  40 , clip  62 , and integrated airbag panel  10  is locked to structure  50  along axis  56  and cannot be axially removed without destroying first fastener clip  62 . In an alternate example shown in  FIG. 3A , an alternate aperture  42  is used. In this example, an alternate clip  62  (not shown) is configured to cooperate with aperture  42  so that clip  62  is normally locked from axial movement but may be manipulated, for example turning  90  degrees about axis  56  to unlock and remove the clip without damaging the clip. This would be useful following deployment of airbag  22  or for simple maintenance of integrated airbag panel  10  or surrounding components. Similar alternate apertures  42  and coordinating removable fasteners, for example where a separate mechanical fastener is used for first fastener body portion  54  and attachment to mounting base  70 , may be used. 
         [0032]    In exemplary operation, on signal from a controller (not shown) of an impact event warranting deployment of airbag  22 , inflator  28  is activated to inflate airbag  22 . As best seen in  FIGS. 5 and 6 , during inflation of airbag  22 , gaseous interior chamber  24  will begin to rapidly expand. During the rapid expansion, first fastener body portion  54  is placed under extreme tensile stress along longitudinal axis  56 . Airbag panel  10  having only connection to structure  50  through first fasteners  34  and being the weakest link in the connection of airbag panel  10  to structure  50 , fastener  34  quickly fractures under stress of the expanding airbag  22 . The fracture of body portion  54  preferably allows free movement of the integrated airbag panel  10 , as a unit, away from structure  50  as the airbag expands. In an alternate example, body portion  54  does not fracture, but enlarged end  58  is pulled back through bore  68  along axis  56  thus mechanically separating body portion  54  and clip portion  62  of first fastener  34  (shown in  FIG. 5  in phantom). 
         [0033]    Referring to  FIG. 5 , in a preferred example, whether first fastener  34  fractures or mechanically separates as described above, clip portion  62 , and airbag  22  remains connected to structure  50  as best seen in  FIGS. 5 and 6 . In this example, clip portion  62  and airbag  22 , being connected to structure  50  and trim panel  12 , acts as a tether limiting movement of trim panel  12  away from structure  50  It is understood that other devices (not shown) may serve as tethers, for example, separate straps connected to trim panel  12  and structure  50  known by those skilled in the art may be used 
         [0034]    In a preferred example shown in  FIG. 6 , airbag  22  forcefully presses against structure  50 , thrusting integrated airbag panel  10  away from structure  50 , preferably A-pillar body structure, toward the interior compartment  18  and preferably in a direction toward a passenger to further prevent the passenger from striking the rigid body structure  50 . By the entire integrated airbag panel  10  moving as a unit away from the A-pillar structure  50 , a greater area of protection, substantially the entire length of the vehicle A-pillar, is achieved which is advantageous over prior designs. The movement of the integrated airbag panel  10  further removes the difficulties and complexities experienced in prior designs in which the airbag expanded through the fracture or disintegration of the trim panel itself, or the trim panel being hinged out of the way, but remained at least partially attached to the vehicle structure through direct connection or tether straps. 
         [0035]    In an alternate example (not shown), airbag  22  may be configured to provide a larger volume in interior chamber  24  at an upper portion, higher on the A-pillar, and a lesser volume near the lower portion of the A-pillar to provide increased cushioning for an occupant&#39;s head. Alternately, different areas of airbag  22  may have increased or decreased volume or thickness to suit the particular application and cushioning requirements. 
         [0036]    In a preferred method of assembly, a moveable integrated airbag panel  10  is assembled as described above and as best shown in  FIGS. 1-4 . The integrated airbag panel  10  is attached to the vehicle body structure  50  in the manner described above and best shown in  FIGS. 2 and 3 . 
         [0037]    While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.