Instrument panel system with hidden airbag door

An instrument panel includes, in an exemplary embodiment, a thermoplastic base substrate having a first surface and an opposing second surface, and a door portion defined by a tear seam notch in the first surface of the base substrate. The tear seam notch defines a periphery of the door portion. The instrument panel also includes at least one hinge portion defined by a plurality of tear seam notches in the first surface of the base substrate. Each hinge portion interrupts the door portion tear seam notch so that the door portion tear seam notch is not continuous.

BACKGROUND OF THE INVENTION

This invention relates generally to instrument panel assemblies, and more particularly to an instrument panel having a hidden airbag door.

Known instrument panel assemblies include a beam structure and at least one decorative instrument panel attached to the beam structure. Some of the decorative panels act as knee bolsters to protect the knees of vehicle occupants in the event of an impact. An instrument panel assembly is mounted inside the passenger compartment of an automobile with the beam structure attached to the automobile body, typically to the A-pillar. Known instrument panel beam structures are fabricated from steel or plastic.

A number of vehicle systems are housed within the instrument pane assembly, for example, the heating, ventilating, and air conditioning (HVAC) system, and the airbag system(s). To permit deployment of the airbag, the instrument panel includes a airbag opening covered by an airbag door. The placement of a door in the middle of a smooth surfaced instrument panel is considered as aesthetically unacceptable because the door destroys the clean aesthetic lines of an instrument panel. The deployment of the airbag forces the door open to permit the airbag to exit through the opening in the instrument panel.

A known instrument panel having a hidden airbag door includes a molded base substrate that is either covered with a semi-rigid foam and a cover material, painted, or left unpainted. The underside of the instrument panel base substrate is scored with a laser to create a deployment seam in the shape of a door. A separate metal hinge assembly is molded into the back of the door and the underside of the base substrate to permit the door to pivot open during airbag deployment. The force of the airbag deployment forces the deployment seam to separate permitting the door to be forced open. If required, the door is also forced through the surface foam  layer and the cover layer of the instrument panel so the airbag can exit the instrument panel. The underside of the cover layer has either a seam that is molded in, or is laser scored to facilitate the door breaking through the cover. The multiple components of the airbag door hinge increases complexity of fabrication and assembly which increases fabrication time and increases labor costs.

BRIEF DESCRIPTION OF THE INVENTION

In one aspect, an instrument panel is provided. The instrument panel includes a thermoplastic base substrate having a first surface and an opposing second surface, and a door portion defined by a tear seam notch in the first surface of the base substrate. The tear seam notch defines a periphery of the door portion. The instrument panel also includes at least one hinge portion defined by a plurality of tear seam notches in the first surface of the base substrate. Each hinge portion interrupts the door portion tear seam notch so that the door portion tear seam notch is not continuous.

In another aspect, an instrument panel system is provided that includes an instrument panel and an airbag. The air bag is positioned adjacent the instrument panel. The instrument panel includes a thermoplastic base substrate having a first surface and an opposing second surface, and a door portion defined by a tear seam notch in the first surface of the base substrate. The tear seam notch defines a periphery of the door portion. The instrument panel also includes at least one hinge portion defined by a plurality of tear seam notches in the first surface of the base substrate. Each hinge portion interrupts the door portion tear seam notch so that the door portion tear seam notch is not continuous.

In another aspect, a thermoplastic panel that includes a hidden airbag door is provided. The thermoplastic panel also includes a thermoplastic base substrate having a first surface and an opposing second surface, and a tear seam notch in the first surface of the base substrate. The tear seam notch defines a periphery of the airbag door. The thermoplastic panel further includes at least one hinge portion defined by a plurality of tear seam notches in the first surface of the base substrate.  Each hinge portion interrupts the airbag door tear seam notch so that the airbag door tear seam notch is not continuous.

DETAILED DESCRIPTION OF THE INVENTION

An instrument panel system that includes an instrument panel with a hidden airbag door is described below in more detail. The airbag door is not visible to vehicle occupants before deployment of the airbag. The hidden airbag door is self-hinging and opens by the force of the airbag deploying and permits the airbag to exit the instrument panel and enter the passenger compartment. The opened airbag  door includes smooth surfaces without sharp and/or hard edges to avoid vehicle occupant injuries.

Referring to the drawings,FIG. 1is an exploded perspective view of an instrument panel assembly10in accordance with an exemplary embodiment of the present invention. Instrument panel assembly10includes an instrument panel12having duct outlet openings14,16,18, and20. Vent grills22,24,26, and28are sized to mate with openings14,16,18, and20respectively. An instrument cluster30and a cluster trim plate32are coupled to instrument panel12. Cluster trim plate32includes vent grills34and36. A driver side knee bolster38and a glove box surround40are coupled to instrument panel12. A glove box42attaches to a glove box hinge portion44of glove box surround40. The combination of glove box surround40and glove box42act as a passenger knee bolster. A center bezel46is coupled to driver side knee bolster38and glove box surround40. A fuse access door48covers a fuse access opening50in glove box surround40. An airbag module52is mounted adjacent instrument panel12.

FIG. 2is a bottom schematic view of a portion of instrument panel12, andFIG. 3is a cross sectional view of instrument panel12through line C—C. Referring toFIGS. 2 and 3, a base substrate54includes an upper surface56and a lower surface58. When instrument panel12is installed in a vehicle, upper surface56faces the passenger compartment and lower surface58faces the inside of instrument panel assembly10. Base substrate54includes a tear seam notch60that defines the outer periphery of an airbag door62. In this exemplary embodiment, tear seam notch60is located in lower surface58of base substrate54. In an alternate embodiment, tear seam notch60is located in upper surface56of base substrate54. At least one hinge portion64(two shown) is defined by hinge tear seam notches66in base substrate54. Each hinge portion64is located so that it interrupts airbag door tear seam notch60. Particularly, tear seam notch60is non-continuous in the area of each hinge portion64creating a self-hinging airbag door. Hinge portion tear seam notches66are substantially orthogonal to airbag door tear seam notch60. In the exemplary embodiment, hinge portion tear seam notches66extend from a  location in airbag door62to a location away from airbag door62. In an alternate embodiment shown inFIG. 4, hinge portion tear seam notches66extend from airbag door tear seam notch60to a location away from air bag door62. In another alternate embodiment shown inFIG. 5, hinge portion tear seam notches66extend from a location in airbag door62to airbag door tear seam notch60.

Hinge tear seam notches66are curved with a relatively small radius of curvature to prevent ripping of base substrate54adjacent hinge tear seam notches66. In the exemplary embodiment, the tear seam notches66that form each hinge portion64are arranged so that the width of hinge portion64is smallest at the intersection with airbag door tear seam notch60. Hinge portions64have a thickness that is substantially equivalent to the thickness of airbag door62and instrument panel12. Hinge portions64connect airbag door62to instrument panel12during and after an airbag deployment event which permits airbag door62to open allowing airbag52to fully inflate through instrument panel12.

Tear seam notches60and66can be formed in base substrate54by any suitable method. Some suitable methods for forming tear seam notches60and66include, but are not limited to, press molding tear seam notches60and66into base substrate54, forming tear seam notches60and66during the injection molding of base substrate54, laser scribing tear seam notches60and66into base substrate54, scribing tear seam notches60and66into base substrate54with a high pressure water stream, and scribing tear seam notches60and66into base substrate54with a hot knife tool. A cross-section of tear seam notches60and66can have any suitable shape, for example, a V-shape, a U-shape, a conical-shape, a spherical-shape, or a box shape.

Flexible properties of base substrate54permit bending and flexing of hinge portions64which permit airbag door62to open during an airbag deployment event. Base substrate54should be flexible at temperatures of about 100° C. to about −40° C. Base substrate54can be extruded or molded from one of many thermoplastic materials. Suitable thermoplastic materials include, but are not limited to, acrylonitrile-butadiene-styrene (ABS), polycarbonate (LEXAN® and  LEXAN® EXL resins commercially available from General Electric Company), polycarbonate/ABS blend, a copolycarbonate-polyester, acrylic-styrene-acrylonitrile (ASA), acrylonitrile-(ethylene-polypropylene diamine modified)-styrene (AES), phenylene ether resins, glass filled blends of polyphenylene oxide and polystyrene, blends of polyphenylene ether/polyamide (NORYL GTX® resins from General Electric Company), blends of polycarbonate/PET/PBT, polybutylene terephthalate and impact modifier (XENOY® resins commercially available from General Electric Company), polyamides, phenylene sulfide resins, polyvinyl chloride PVC, high impact polystyrene (HIPS), low/high density polyethylene, polypropylene and thermoplastic olefins (TPO), polyethylene and fiber composites, and polypropylene and fiber composites such as AZDEL Superlite™ sheets commercially available from AZDEL, Inc.

Referring toFIG. 3, instrument panel12includes an intermediate layer70on upper surface56of base substrate54and a cover layer72on upper surface74of intermediate layer70. In an alternate embodiment, instrument panel12does not have any additional layers on upper surface56of base substrate54. In another embodiment, upper surface56of base substrate54is be painted. Intermediate layer70is formed from a resilient material, for example, a foam material. The resilient material provides protection to vehicle occupants in impact events. Cover layer72is formed from any suitable decorative material, for example, a thermoplastic material, leather, fabric, and the like. With the application of intermediate layer70and cover layer72to base substrate54, airbag door62is not visible to a vehicle occupant. In the exemplary embodiment, intermediate layer70and cover layer72do not contain tear seam scores or notches to aid the opening of airbag door62. In other embodiments, at least one of intermediate layer70and cover layer72also include tear seam notches.

In operation, during an airbag deployment event, airbag52inflates and imparts a force on instrument panel12. The force causes tear seam notches60and66to open and causes airbag door62to move to an open position by breaking through intermediate layer70and cover layer72. With airbag door62and  in an open position, airbag52can fully inflate through instrument panel12. Open airbag door62has smooth surfaces without sharp/hard edges to avoid vehicle occupant injuries.

FIG. 6is a schematic illustration of a portion of instrument panel12in accordance with another exemplary embodiment of the present invention. An outer periphery of an airbag door80in instrument panel12is defined by a tear seam notch82located in lower surface58of base substrate54. Air bag door80includes segments84and86and includes a segment tear seam notch88located between segments84and86and intersecting airbag door tear seam notch82at each end. Particularly, the outer periphery of airbag door segments84and86are defined by airbag door tear seam notch82and segment tear seam notch88. The exemplary embodiment shown inFIG. 6has two airbag door segments84and86; however, in alternate embodiments air bag door80can have more than two door segments and more than one segment tear seam notch to define the door segments.

At least one hinge portion90is defined by hinge tear seam notches92in base substrate54. Each hinge portion90is located so that it interrupts airbag door tear seam notch82. Particularly, tear seam notch82is non-continuous in the area of each hinge portion90. Hinge portion tear seam notches92are substantially orthogonal to airbag door tear seam notch82and extend from a location in airbag door segment84or86to a location away from airbag door80. Each door segment84and86are connected to instrument panel12by at least one hinge portion90. In an alternate embodiment hinge portion tear seam notches92extend from airbag door tear seam notch82to a location away from air bag door segment84or86. In another alternate embodiment hinge portion tear seam notches92extend from a location in airbag door segment84or86to airbag door tear seam notch82. Hinge tear seam notches92are curved with a relatively small radius of curvature to prevent ripping of base substrate54adjacent hinge tear seam notches92. In the exemplary embodiment, the tear seam notches92that form each hinge portion90are arranged so that the width of hinge portion90is smallest at the intersection with airbag door tear seam notch82.