1. Technical Field
Embodiments of the present invention relate to instrument panels equipped with airbags and to methods for forming such instrument panels.
2. Background Art
Instrument panel covers that have airbags therein and techniques for forming such instrument panel covers are well known in the art.
For example, U.S. Pat. No. 7,100,941 B2 to Riha et al. discloses an apparatus and a method that relate to the use of fabric material in the manufacture of an air bag deployment system. Riha '941 includes an air bag cover for an air bag safety system for a vehicle comprising a fabric outer layer having a frontside and a backside and a substrate containing an opening wherein the opening has a periphery. The substrate is preferably formed by low pressure molding, wherein the fabric outer layer overlies the opening in the substrate, and wherein the fabric outer layer is weakened at a location that is adjacent or overlies the substrate opening periphery.
Several embodiments of the present invention take the form of an instrument panel for a motor vehicle. The instrument panel is equipped with an airbag. The instrument panel includes a pre-constructed substrate and a cover. The substrate includes a mounting surface and a reference surface. The cover includes a woven layer and a cover-skin layer. The woven layer includes an inner surface that is coupled to the mounting surface via an adhesive. The cover skin layer includes an outer surface that defines a stitched region and an airbag region. The stitched region is configured to receive at least one stitch for presentation to an occupant. The airbag region, which is separate from the stitched region, corresponds to at least part of an area where the airbag impacts the cover skin layer during a deployment of the airbag.
Several embodiments of the present invention take the form of a method for forming a motor-vehicle instrument panel that is equipped with an airbag, such as the one described in the previous paragraph. The method includes providing a substrate and a cover, such as those previously described; applying an adhesive to at least one of the substrate and the cover; and wrapping the cover over the substrate to couple the cover thereto.
Several embodiments of the present invention may be best understood by referring to the following Detailed Description in conjunction with the accompanying Figures, in which:
The Figures are not necessarily to scale and may be simplified for clarity.
As used in this section, and unless otherwise indicated, the term “embodiment” refers to “embodiment of the present invention,” the articles “a”, “an”, and “the” comprise plural referents, and all numerical quantities are modified by the word “about”.
The airbag system 26 can be of a conventional type. Referring to
With reference to
In an embodiment, the cover 24 has a thickness, labeled t2 in the shown embodiment, in the range of 1.5 mm to 4.0 mm, layer 44 has a thickness in the range of 0.05 mm to 0.1 mm, layer 46 has a thickness in the range of 0.4 mm to 0.6 mm, and layer 48 has a thickness in the range of 1.0 mm to 3.5 mm. The cover 24 may have at least one layer formed of a woven material. In the shown embodiment, the cover skin 42 is formed of a polyurethane material. The layers 44 and 46 are each formed of a polyurethane material, and layer 48 is formed of a woven material. The cover 24 may be leather or leatherette (e.g., simulated leather), such as, for example, a leather or leatherette cover material produced by Benecke-Kaliko AG of Auburn Hills, Mich. However, in other embodiments, a different number of layers and a different combination of materials can be used. In yet another embodiment, a spray polyurethane skin material may be used for a similar application.
As mentioned, the substrate 27 is coupled to the cover 24 via an adhesive 29. In at least one embodiment, the substrate 27 may be formed of a suitable thermoplastic material including, but not limited to, polycarbonate (PC), thermoplastic olefin (TPO), and polypropylene. In certain embodiments, the substrate 27 has a relatively uniform thickness in the range of 3.0 mm-4.0 mm, at least about the airbag region.
The substrate 27 defines a reference surface 49 from which a plurality of spaced-apart holes 50a-50i extends towards the outer surface 31 in the airbag region 36. The holes 50a-50i generally weaken the cover 24 to enable the airbag 28 to pass through the airbag door and the panel 20 upon deployment. In an embodiment, the types of material used to construct the layers 42,44,46,48 as well as the corresponding ranges used for the layers 42,44,46,48 in combination with the number and depth of the holes 50a-50i may be configured to mitigate a ballooning effect during airbag deployment. Generally, the materials of the layers, the corresponding thicknesses of the layers, and the number and depth of the holes 50a-50i of the various layers 42,44, 46, and 48 of the cover 24 may ensure proper deployment of the airbag from the substrate 27 for controlled tearing of the cover 24 to ensure accurate control of airbag inflation. The types of materials used to construct the layers, and the respective thicknesses of the materials and the number and depth of holes 50a-50i may eliminate the need to pre-treat the cover 24 in order to weaken the cover 24 during airbag deployment.
As shown, each hole 50a-50i extends from the reference surface 49, through the substrate 27, and into at least one of the layers 42,44,46,48 of the cover 24. The holes 50a-50i may optionally, but not necessarily, extend into a portion of the cover skin 32. As shown, the holes 50a, 50b, 50d, and 50h extend into layer 46 of the cover 24, the holes 50c, 50e, 50f, and 50i extend into layer 44 of the cover 24, and the hole 50g extends partially into the cover skin 42 of the cover 24. In at least one embodiment, the holes 50a-50i may have a depth of 3.0 mm-7.0 mm.
Still referring to
Referring to
In block 74, the method includes providing a cover, such as the cover 24. For example, the cover 24 may be pre-fabricated, with all the layers coupled to one another. However, block 74 may, in other embodiments, include coupling the various layers to one another, for example, via adhesive. As mentioned, the instrument panel 20 defines a stitched region 38. In an embodiment, at least one of the stitches 52a-52d in the stitched region 38 are ornamental and provide an aesthetic appearance to vehicle occupants. However, in another embodiment, at least one of the stitches 52a-52d may at least partially couple one or more of the layers 42-48 together.
In block 76, the adhesive 29 is applied to one or more of the substrate 27 and the cover 24. The adhesive 29 may be applied to the bottom layer 51 of the cover 24, to the top layer 53 of the substrate 27, or to both the bottom layer 51 of the cover 24 and the top layer 53 of the substrate 27. The adhesive 29 may be of any suitable type and may be dictated by the particular materials used to form the cover 24 and/or the material used to form the substrate 27.
In block 78, the cover 24 is wrapped over the substrate 27 to coupled the cover 24 to the substrate 27. In an embodiment, the cover 24 is hand-wrapped over a pre-molded substrate 27. However, various wrapping methods may be used to couple the cover 24 to the substrate 27, including, but not limited to, a vacuum wrapping process. The vacuum wrapping process may be one where a top of the cover 24 (e.g., the surface visible to a vehicle occupant) is mounted on a mold surface that includes holes positioned over at least a substantial portion of the surface. Once the top of the cover 24 is mounted on the mold surface, a negative pressure is applied, causing a vacuum effect that holds the cover tightly against the mold surface to mitigate any “wrinkling” of the cover 24. A predetermined amount of adhesive may be applied (e.g., sprayed) to the back side of the cover 24 at a proper temperature such that the pre-constructed substrate 27 is positioned about the back side of the cover 24. The cover 24 is then wrapped around the surface of the substrate 27 where the cover 24 is bonded to the substrate 27. A plurality of staples (not shown) are applied to non-visible sections of the cover 24 to further couple the cover 24 to the substrate 27.
The cover 24 and the substrate 27 may not be coupled to one another via a molding process (e.g., pressure molding). In this manner, the cover 24 and the substrate 27 may be fabricated separately and coupled to one another following fabrication. This may allow for various types of stitching on the cover 24 and/or mitigate the substrate mold and/or adhesive from “bleeding through” the stitch channels 54a-54d.
While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and various changes may be made without departing from the spirit and scope of the present invention.