Integrated airbag panel

[0001] This invention generally pertains to the field of supplemental restraint systems for passenger vehicles and more particularly to safety airbags.

[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.

[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.

[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'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.