Background Of The Invention Motor vehicle headliners typically comprise a trim layer, or outer, layer that presents a major exterior appearance of the vehicle ceiling, a foam intermediate layer, and some form of a structural component. The structural component provides the headliner with structural integrity so that the headliner will maintain its installation configuration without sagging when attached to the roof panel of the vehicle. A typical example of a prior art headliner is described in United States patent nos. 5,683,796 and 5,721,038.

The headliner is typically fastened to the roof panel of the vehicle through the use of fasteners or adhesives. Magnets are also commonly used to attach the headliner to the roof panel.

Additionally, the roof panel must also be reinforced to prevent sagging. Bows are commonly used with the headliner to provide structural support for the headliner and at the same time, the roof panel.

The use of fasteners and bows is cumbersome and time consuming. Additionally, as the headliner is made more rigid, it becomes more difficult to insert it through a window of a partially assembled vehicle since the width of the headliner often exceeds the width of the front or rear window opening.

Summary Of The Invention The disadvantages of the prior art may be overcome by providing a roof module assembly which is molded to the roof panel, thereby providing structural support to both the headliner and the roof panel.

According to one aspect of the invention, there is provided a roof module assembly for a passenger vehicle having a foam substrate including an upper surface and a lower surface. A decorative trim cover layer is molded to the lower surface of the foam substrate.

The upper surface of the foam substrate is molded to an exterior roof panel for providing structural support to the exterior roof According to another aspect of the invention, there is provided a method of making a roof module assembly comprising the steps of providing a trim layer in a contoured mold, positioning an exterior roof panel in spaced relation with the trim cover layer defining a foaming cavity therebetween, providing a foaming composition between the roof panel and the trim cover layer, expanding the foaming composition to fully occupy the foaming cavity and cured to formed a foam substrate self bonded between the roof panel and trim cover layer, and removing roof module assembly from the mold.

Brief Description Of The Drawings Figure 1 is a partial cross-sectional view of the roof module assembly having overhead components molded therein; Figure 2 is a partial cross-sectional view of the roof module assembly showing an interface with a vehicle door; and Figure 3 is a front view of a mold associated with the method of making the roof module assembly.

Detailed Description Of The Preferred Embodiment Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a sectional view of a roof module assembly 10 for use in an automotive vehicle is generally shown in Figures 1 and 2.

The roof module assembly 10 includes an exterior roof panel 12 having a generally planar underside 14 with an upper surface of a polyurethane foam substrate 16 bonded thereto. A trim layer 18 of headliner fabric or trim cover material is adhered to the lower surface of the foam 16 such that the foam 16 is disposed between the roof panel 12 and the trim layer 18. The trim layer 18 forms an interior overhead surface and comprises either woven or non-woven material, such as cloth, or any other material commonly used in an automotive interior as may be desired, including felt type materials. Additionally, the trim layer 18 could comprise a multi layer laminate composite having a fabric layer, a soft foam layer and a film layer. The foam substrate 16 is molded to complement the aesthetic, and dimensional requirements of the interior overhead surface.

A generally U-shaped structural support beam 19 is affixed to the underside 14 of the roof panel 12 along a longitudinal periphery 20 of the roof panel 12. The outer peripheral edge of the roof panel 12 is curled around a portion of the support beam 19 and forms a flange 22 with the support beam 19 for securing the support beam 19 to the roof panel 12. However, spot welds may be added between the support beam 19 and the roof panel 12, if necessary. Additionally, the support beam 19 provides structural support to the roof module assembly 10 during assembly operations and thereafter.

The roof panel 12 is typically a solid, planar stamped piece of sheet metal. Roof panel 12 is preferably primed and painted with a polyurethane based paint.

As an alternative, however, the roof panel 12 can be formed, or molded, out of a composite material such as, for example an organic plastic material. A plastic roof panel 12 would provide an additional mass savings to the vehicle, while the foam substrate 16 provides sufficient structural support to the plastic roof panel 12 eliminating the need for structural cross car beams. The plastic roof panel 12 may be affixed to the support beam 19 with a structural adhesive or an equivalent.

As shown in Figure 1, a lamp 24 may be molded into the foam 16. The lamp 24 can be positioned in the roof module assembly 10 at any location, such as, for example, adjacent the support beam 19, above the driver's seat and passenger's seat, and the rear seat. One or more electrical wiring harnesses 26 may also be molded into the roof module assembly 10 for providing electrical current to the lamp 24 and to any other electrical component disposed upon the roof module assembly 10. The wiring harness 26 includes a free hanging connector for connecting to the vehicle electrical harness as is known in the art of vehicle electrical circuits. The connector is typically located along a side panel of the vehicle.

The roof module assembly 10 may further include a heating, venting and air conditioning duct 28 (HVAC) disposed within the foam 16 for meeting HVAC requirements for the vehicle passenger compartment.

The roof module assembly 10 may include any of the components typically associated with vehicle overhead systems such as, for example, head impact protection panels, head impact protection air bags, tear seams for air bag deployment, a sun roof, coat hooks, assist grips, overhead consoles, speakers and sun visors.

As shown in Figures 1 and 2, the vehicle includes a structural roof rail 30 concealed by an exterior sheet metal flange 32 which is fixedly attached to the structural roof rail 30.

The exterior flange 32 forms a surface to which the roof module assembly 10 is affixed. A structural adhesive 34 is disposed between the exterior flange 32 and the support beam 19 for securing the roof module assembly 10 to the roof rail 30, and thus, to the vehicle.

However, other methods of attachment are contemplated as a particular design may require.

The foam 16 and the trim layer 18 is formed to define a lip 36 presenting a channel 37 for aligning, receiving and attaching a first end 39 of an interior body side trim panel 38 with the roof module assembly 10. The body side trim panel 38 covers and conceals the structural roof rail 30 and other body components from view within the interior compartment of the vehicle. The lip 36 extends from the A-pillar of the vehicle to the side panel for providing alignment for the full length of the passenger compartment.

As shown in Figure 2, the body side trim panel 38 is aligned and attached at an opposite second end 41 to the lip 36 by a mounting clip 40 having a bulb seal 42 adjacent a vehicle door 44 for sealing and preventing outside elements from entering the passenger compartment as is known in the art of vehicle weather proofing.

Referring to Figure 3, the roof module assembly 10 of the present invention is manufactured by providing a molding apparatus. Preferably, the molding apparatus utilized to carry out the method of the present invention is more particularly described in United States patent nos. 5,683,796 and 5,721,038. Alternatively, a reaction injection molding (RIM) apparatus could also be utilized.

Trim layer 18 is placed on a movable upper mold 54. The upper mold 54 includes a contoured mold surface 47 for supporting the trim layer 18. Optionally, the upper mold 54 is provided with vacuum ports connected to a source of vacuum to draw the trim layer 18 into contact with the mold surface 47.

The roof panel 12 is mounted in cavity 50 of a lower mold 48. Magnets or clips are provided to retain the roof panel 12 in the lower mold 48. The roof panel 12 is positioned in a spaced relation with the trim layer 18 defining a foaming cavity 52 therebetween.

The desired accessory components, such as the interior lamp 24, HVAC ducts 28 and/or wiring harness 26, are then positioned on the roof panel 12.

A polyurethane foaming composition is poured or sprayed into the foaming cavity 52 and between the roof panel 12 and the trim layer 18 and allowed to expand or free rise as the upper mold 54 is closed. The foaming composition continues until it fully occupies the foaming cavity 52 and cures to form the polyurethane foam substrate 16. As the

polyurethane foam cures the upper surface forms a tacky skin. The skin rises until it contacts the roof panel 12, which restricts further rising and adheres thereto. The substrate 16 will become integrally or self bonded to the roof panel 12 and the trim layer 18, forming a composite or sandwich construction.

Preferably, the polyurethane foam substrate 16 is a closed cell rigid material in the range of 4 to 7 pounds per cubic foot.

The roof module assembly 10 is removed from the lower mold 46 and may then be assembled into a partially assembled vehicle. The roof module assembly 10 is presented to the structural adhesive 34 disposed on the exterior flange 32.

The invention has been described in an illustrative manner, and it is to be understood that the terminology which has been used is intended to be in the nature of words of description rather than of limitation. Many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that the invention may be practiced otherwise than as specifically described.