Patent Application
20090315303
The invention relates to air bags and more particularly to methods for controlling the deployment force of a seamless airbag.
Vehicle manufacturers face many challenges when incorporating airbags into vehicle interiors. Currently, airbags may be employed in several locations in a vehicle including seats, pillars, and instrument panels. In each of these applications, the aesthetic appearance of the airbag installation may be an important factor. Additionally, airbags must be incorporated in a cost effective manner while remaining able to sufficiently control rapid and forceful deployments.
Ideally, an airbag incorporated into the interior of a vehicle should give no outward appearance of its presence. A seamless integration into an interior trim panel is preferred by consumers, who have no desire to see tear seams within a vehicle. Additionally, the materials comprising the trim panel and the deployment section of the trim panel should provide a consistent feel of texture and hardness. To meet this end, tear seams defining portions of a trim panel through which the airbag is deployed are preferably located on the under side of a trim panel, not visible to a consumer.
Reduction of the number of components or the amount of material required by an airbag system are typical ways a manufacturer may reduce costs while maintaining aesthetic integration. Additionally, a system requiring fewer manufacturing steps may provide a cost advantage over other airbag systems. A cost effective airbag system may provide a consumer with greater value by allowing a manufacturer to expend resources elsewhere.
Airbag chutes have traditionally been used to control airbag deployment forces on trim panel sections. Chutes are generally metal and surround an airbag canister and provide a hinging area which deflects and guides the airbag toward a deployment section of the trim panel. While effective, airbag chutes are a heavy and expensive component, which if eliminated from an airbag system would provide a substantial cost savings. Flexible guiding systems may be used to circumvent the necessary use of a chute, but have required extensive reinforcement of trim panels or guiding material designed to tear during airbag deployment.
Deployment sections of trim panels, when not used in conjunction with an airbag chute, have required costly and extensive reinforcement of the trim panel. Reinforcement typically includes bonding a flexible sheet of material, such as woven nylon, to the underside of a trim panel in an area that is greater than the deployment section. Trim panel reinforcement militates against fragmentation of the trim panel and deployment section, while providing a “hinge” for the deployment section of the trim panel. Additionally, trim panel reinforcement militates against a deploying airbag from exiting the trim panel in any area other than the deployment section, defined by tear seams or weakened reinforcement.
A size of the deployment section, in relation to the size of the airbag canister will dictate the trim panel reinforcement necessary. Where a deployment section is of substantially the same size as the airbag canister or smaller, extensive trim panel reinforcement is generally necessary, as well as the presence of airbag guides on all sides of the airbag canister. As disclosed in U.S. Pat. No. 6,079,733, trim panel reinforcement and airbag guiding may be accomplished by the same piece of material when the deployment area encompasses approximately the same area as the airbag canister. Despite being a functional design, a large amount of material is required to guide the airbag, in addition to trim panel reinforcement outside of the deployment area, necessitating additional material and manufacturing cost.
Reinforcement for trim panels and an airbag guiding material must be strong yet flexible, and generally is composed of woven nylon fibers having a polymeric covering. Typically known as “scrim” material, it is commonly incorporated into airbag systems as a reinforcing, guiding, and hinging material. Despite being a rather inexpensive material for reinforcing, guiding, and hinging, “scrim” has a tendency to tear under deployment forces, affording inconsistent performance when used. Alternatives to “scrim”, like steel hinge systems and thermoplastic olefin trim components, have generally been excessive in cost and weight.
It would be desirable to produce a system for controlling the deployment force of an airbag, wherein the system facilitates airbag deployment without trim panel reinforcement. Additionally, a system that militates against fragmentation of the trim panel and deployment section that is lightweight and cost effective would be particularly advantageous.
Presently provided by the invention, a system for controlling the deployment force of an airbag that is lightweight and cost effective, wherein the system facilitates airbag deployment without trim panel reinforcement that militates against fragmentation of the trim panel and deployment section has surprisingly been discovered.
In one embodiment, the system for controlling the deployment force of a vehicle airbag comprises a trim piece including a deployment section having a first length, an airbag housing, wherein the housing is rigidly affixed within a vehicle and disposed adjacent the trim piece, the housing having a second length less than the first length, and a reinforced sheet having a width, the width greater than the second length, wherein the reinforced sheet is securely attached to the deployment section and the housing.
In another embodiment, the system for controlling the deployment force of a vehicle airbag comprises a trim piece including a deployment section having a first length, an airbag housing, wherein the housing is rigidly affixed within a vehicle and disposed adjacent the trim piece, the housing having a second length less than the first length, a first reinforced sheet having a first width, the first width greater than the second length, wherein the first reinforced sheet is securely attached to the deployment section and the housing, and a second reinforced sheet having a second width greater than the second length, wherein said second reinforced sheet is secured to said trim piece and said housing.
The invention also provides methods for controlling the deployment force of an airbag.
In one embodiment, the method for controlling the deployment force of a vehicle airbag comprising the steps of providing a trim piece including a deployment section having a first length, providing an airbag housing, the housing having a second length less than the first length and an airbag within, providing a reinforced sheet having a width, the width greater than the second length, attaching the reinforced sheet to the deployment section of the trim piece, disposing the airbag housing adjacent the trim piece, wherein the airbag housing is rigidly affixed within the vehicle, attaching the reinforced sheet to the airbag housing, deploying the airbag, causing the airbag to impact the reinforced sheet, exerting force on the deployment section, separating the deployment section from the trim piece, and restraining the deployment section during airbag deployment, the deployment section restrained by the reinforced sheet, wherein the reinforced sheet is restrained by attachment means to the airbag housing.
The above, as well as other objects and advantages of the invention, will become readily apparent to those skilled in the art from reading the following detailed description of a preferred embodiment of the invention when considered in the light of the accompanying drawings in which:
The following detailed description and appended drawings describe and illustrate an exemplary embodiment of the present invention. The description and drawings serve to enable one skilled in the art to make and use the invention, and are not intended to limit the scope of the invention in any manner. It is understood that materials other than those described can be used without departing from the scope and spirit of the invention. In respect of the methods disclosed, the steps presented are exemplary in nature, and thus, the order of the steps is not necessary or critical.
The trim piece 12 can be produced from any conventional material used to manufacture vehicle interior panels such as vinyl and plastic, for example. As shown, the trim piece 12 is an instrument panel, but other panels such as vehicle doors, pillars, center consoles, and ceilings may be used. Additionally, the trim piece 12 can be manufactured through any conventional process such as injection molding. The trim piece 12 has an outer surface 18 facing towards an interior of the vehicle, and an inner surface 20. The outer surface 18 may be textured or formed of a material that has an aesthetic appeal to vehicle occupants. The inner surface 20 includes a tear pattern 22 defining a deployment section 24 of the trim piece 12. The inner surface 20 may also include a fastening means (not shown) such as attachment points or a rigid structure for attaching the trim piece 12 to the vehicle.
The tear pattern 22 may include a groove 26 as illustrated in
As illustrated in
Shown in
The reinforced sheet 16 may be formed from any conventional material such as a plurality of laminated sheets of a strong and flexible material such as a woven polypropylene fiber. The reinforced sheet 16 may have a rectangular shape, having the width W, and two ends substantially perpendicular to the side having the width W. A first end 42 is securely attached to the deployment section 24. Any conventional method such as sonic welding, integral molding, or an adhesive may be used to securely attach the first end 42 to the deployment section 24. A second end 44 is fastened to the airbag housing 14. As shown in
The deployment sections 24 of the trim panel 12 are restrained from becoming projectiles under the force of the deploying airbag 30 by the reinforced sheets 16 to which they are bonded. The reinforced sheets 16 act as a “hinge” for the deployment sections 24, pivoting them towards the outer surface 20 of the trim panel 12. Portions of the trim panel 12 that are not deployment sections 24 do not fragment because the deployment sections 24 and reinforced sheets 16 have the length L1 and the width W greater in magnitude than the length L2 of the airbag housing 14. Accordingly, reinforcement of the trim panel 12 is not required in an area larger than the deployment sections 24, resulting in a lightweight and cost effective solution to controlling the deployment force of an airbag 30.
From the foregoing description, one ordinarily skilled in the art can easily ascertain the essential characteristics of this invention and, without departing from the spirit and scope thereof, can make various changes and modifications to the invention to adapt it to various usages and conditions in accordance with the scope of the appended claims.
