Abstract:
A roof module for a motor vehicle and a process of producing a roof module which includes at least two flat roof covers located adjacent to one another and which are joined to one another using a tool which disperses a peripheral foam material.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention is directed generally to a roof module for a motor vehicle and a process of producing a roof module for a motor vehicle. 
     2. Description of the Prior Art 
     It is conventional for roof covers for motor vehicle roofs, for example, transparent glass panes or solar cell covers, to be individually foamed around the periphery of the roof with a suitable plastic such as polyurethane (PUR). As disclosed in German Patent Publication DE 41 05 396 A1, this is done in order to attach mounting covers for mounting on or support in a roof frame. Often it is desirable to integrate several such covers in a motor vehicle roof, however, the production, handling and mounting of the individual covers overall are rather complex. In addition, the individual covers must be sealed against one another and must also be aligned vertically (Z direction) to one another. 
     U.S. Pat. No. 5,409,290 discloses a glass plate for a motor vehicle roof which is connected to a reinforcing plate located at least in component areas thereunder, with peripheral plastic foaming. 
     SUMMARY OF THE INVENTION 
     In view of the foregoing, it is an object of the present invention to provide a roof module for a motor vehicle roof and a process of producing such a roof module having flat covers to provide an overall simple production, handling and installation. 
     These and other objects are achieved with a roof module having at least two flat roof covers which are located adjacent to one another and which are joined thereto around the outer periphery with foam from a foaming tool. In accordance with the present invention, it is advantageous that several functional flat roof covers are used to enhance the production of the roof module. This is so since only one foaming process using only one foaming tool is necessary, and thereby, handling and mounting are simplified, since it requires that only one roof module be handled in order to mount the entire module on the motor vehicle. Furthermore, the foaming technique makes it possible for flat covers of different thickness and/or made of different materials to be peripherally foamed together, to thereby create a “flush design” between individual covers whereby all tolerances can be equalized in all three spatial directions in the foaming tool. 
     Preferably, the peripheral foaming is made of polyurethane. In an exemplary embodiment of the present invention, one of the flat roof covers is transparent while the other is opaque and preferably includes a plurality of solar cells. The roof module is preferably made as a fixed glass cover, but may also be a selectively movable glass cover. In another exemplary embodiment, the flat roof module in an edge area is continuously foamed around the edge in order to hold a seal to thereby prevent leakage in these areas. In another embodiment of the invention, the flat roof covers in the area in which they border one another are adjoined by a peripheral foaming area into which a reinforcement such as a sheet metal insert is foamed at the same time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 shows an overhead view of a roof module in accordance with the present invention; 
     FIG. 2 shows a section along the line II—II in FIG. 1; 
     FIG. 3 shows a section along the line III—III in FIG. 1; and 
     FIG. 4 shows an overhead view of a motor vehicle roof in which the roof module shown in FIG. 1 is installed. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     FIGS. 1 through 3 show a roof module for a motor vehicle and which includes a fixed glass cover  10  having a transparent glass pane  12  and a cover  14  adjoining the transparent glass pane  12  along a horizontal direction. As shown in FIG. 1, the cover  14  is provided with a plurality of solar cells  16  for producing solar current for recharging a motor vehicle battery and/or for operating other motor vehicle systems, for example, a fan. The solar cover  14  is built in the conventional manner and includes a substrate  18  in the form of a glass or plastic pane onto which the plurality of solar cells  16  are laminated. Alternatively, the substrate  18  is composed of sheet metal onto which the solar cells  16  are cemented. Furthermore, the solar cells  16  are provided with a suitable protective cover such as a plexiglass pane. 
     The glass pane  12  and the solar cover  14  in the horizontal direction have a certain distance and are provided on their peripheral edge continuously with peripheral polyurethane foam (PUR)  20 . Of course, instead of polyurethane, other suitable plastics can also be used. As shown in FIG. 2, in the side areas, the peripheral PUR foam  20  is made such that it can hold a seal (not shown) in a groove  21  and thereby, prevent leaking at the cover  10 . In this way, complete sealing of the fixed glass cover  10  can be achieved at least in the side area. However, peripheral foaming is also possible in which there are no grooves  21  because there are seals on the solid roof or due to the fact that the peripheral foam in the edge area is so soft and elastic that it assumes the sealing function. The glass pane  12  and the solar cover  14  are adjoined in an intermediate area  22  therebetween using the peripheral PUR foam  20 . As shown in FIG. 3, for reinforcement in the intermediate area  22  underneath the glass pane  12  and the solar cover  14 , a reinforcing cover in the form of a sheet metal insert  24  is foamed in at the same time. To add aesthetic value to the overall design, in order to cover the peripheral foam area from overhead the glass pane  12  can be provided in the conventional manner with printing (filter). 
     The described roof module  10  is produced by the two flat covers, i.e., the glass pane  12  and the solar cover  14 , being positioned in a foaming tool so that the tolerances in all three spatial directions can be easily equalized by the relative positioning in the foaming tool. The glass pane  12  and the solar cover  14  are peripherally foamed in one step in the foaming tool with PUR and in the intermediate area  22  between the glass pane  12  and the solar cover  14 . The sheet metal insert  24  is foamed in at the same time. Because the glass pane  12  and the solar cover  14  in the intermediate area  22  are adjoined by peripheral foaming  20 , a gap is avoided which would be formed if the glass pane  12  and the solar cover  14  were installed as separate covers in the motor vehicle roof. As a result, sealing problems are avoided and an optically pleasing appearance (“flush design”) is achieved. 
     FIG. 4 shows a motor vehicle roof in which the fixed glass cover  10  shown in FIGS. 1 through 3 is installed. The motor vehicle roof includes a solid roof skin  30  and a roof opening  31  which is made in the solid roof skin  30  and in which a frame (not shown) is attached. The frame bears the fixed glass cover  10  which closes the rear part of the roof opening  31  and seals the opening  31 . A glass pane  12  forms a transparent area from the motor vehicle interior to the inside, an adjustable glass cover  32  which is supported with a pivoting and/or displacement capacity on the frame in order to at least partially clear the front part of the roof opening  31 , and a wind deflector louver  36  which is provided with a plurality of solar cells  34  and which can be pivoted outwardly in order to reduce airstream noise when the cover  32  is selectively placed in an open position. 
     Accordingly, the one-piece execution of the fixed glass cover  10  offers advantages that, although in this way two different flat roof covers  12 ,  14  with different functions can be implemented, sealing problems are avoided, production remains simple, tolerances in production can be easily equalized, covers with a different thickness or made of different materials can be used, and handling, especially installation, remains simple because only one roof module need be handled. 
     Instead of a glass pane and a solar cover, other covers can be used such as at least one of a glass pane provided with a plurality of solar cells, a surface-treated sheet metal, an enameled motor vehicle sheet metal, a plastic pane and the like. And instead of two flat roof covers, multiple covers such as three or more flat covers can be joined to one another in the same way by way of peripheral foaming so that they form a single roof module. 
     Reference Number List 
     fixed glass element  10   
     transparent glass pane  12   
     solar element  14   
     solar cells  16   
     substrate  18   
     peripheral PUR foam  20   
     (seal-holding) groove  21   
     area between  12  and  14   22   
     reinforcing element  24   
     roof skin  30   
     roof opening  31   
     glass cover  32   
     solar cells of  36   34   
     wind deflector louver  36