Abstract:
A method of manufacturing a headliner assembly for use in the interior compartment of an automotive vehicle comprising the steps of: placing a mold release film onto a concave mold surface of a lower mold assembly for providing a barrier against the mold surface; placing a fiber mat on the mold release film; applying a foamable material directly onto the fiber mat; expanding the foamable material around the fiber mat to embed the fiber mat therein; placing an adhesive film onto a convex mold surface of an upper mold assembly; positioning the lower mold assembly directly beneath the upper mold assembly; moving the upper mold assembly in mating engagement with the lower mold assembly to define a mold cavity between the convex mold surface and concave mold surface; curing the foamable material within the mold cavity; and bonding the mold release film and adhesive film to the foamable material with the fiber mat embedded therebetween. A layer of scrim is then adhered to the mold release film and a layer of fabric is adhered to the adhesive film for providing a decorative cover to the headliner assembly.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The subject invention generally relates to a headliner assembly and a method and apparatus for manufacturing a headliner assembly of an automotive vehicle. More specifically, the invention relates to a method and apparatus for manufacturing a headliner assembly having integrated energy absorbing foam.  
           [0003]    2. Description of the Related Art  
           [0004]    Automotive vehicle headliner assemblies are used to line the ceiling or underside of the roof within the interior compartment of the vehicle. The headliner assembly typically includes a fabric layer that provides a decorative cover to the ceiling, a soft flexible foam intermediate layer of a relatively thin configuration, a layer of imperforate urethane film laminate disposed on the surface of the soft foam intermediate layer opposite the fabric layer, and a thick, rigid polyurethane foam layer formed on the imperforate film as the innermost layer of the headliner assembly.  
           [0005]    It is also known to manufacture headliner assemblies having varying thicknesses of urethane foam for providing enhance strength characteristics and acoustical effects. For example, U.S. Pat. No. 5,683,796 discloses a method of making a headliner assembly having an exterior surface of a fabric layer providing a decorative cover and a body of foamed material adhered to the opposite interior surface of the fabric layer having central portions with a greater thickness than peripheral portions thereof. The body of foamed material has a constant density throughout its extent including the central and peripheral portion to provide desired strength, weight and acoustic characteristics to the overall headliner assembly. However, the headliner assembly of this type does not adequately address desired energy absorption characteristics or rigidity for use in mating engagement with the roof of the vehicle.  
           [0006]    Therefore, it is desirable to manufacture a headliner assembly having contoured portions of varying foam thickness and density by embedding a fiber mat within a layer of urethane foam forming a rigid and integrated energy absorbing headliner assembly.  
         SUMMARY OF THE INVENTION  
         [0007]    The present invention relates to a method of manufacturing a headliner assembly for use in the interior compartment of an automotive vehicle comprising the steps of: placing a mold release film onto a concave mold surface of a lower mold assembly for providing a barrier against the mold surface; placing a fiber mat on the mold release film; applying a foamable material directly onto the fiber mat; expanding the foamable material around the fiber mat to embed the fiber mat therein; placing an adhesive film onto a convex mold surface of an upper mold assembly; positioning the lower mold assembly directly beneath the upper mold assembly; moving the upper mold assembly in mating engagement with the lower mold assembly to define a mold cavity between the convex mold surface and concave mold surface; curing the foamable material within the mold cavity; and bonding the mold release film and adhesive film to the foamable material with the fiber mat embedded therebetween. The layer of scrim is then adhered to the mold release film and a layer of fabric is adhered to the adhesive film for providing a decorative cover to the headliner assembly.  
           [0008]    The present invention also relates to a molding apparatus for manufacturing a headliner assembly for use in the interior compartment of an automotive vehicle comprising a support frame. An upper mold assembly is supported by the support frame for vertical movement and includes a convex mold surface. A lower mold assembly is supported by the support frame beneath the upper mold assembly and includes a concave mold surface. The upper mold assembly is movable into mating engagement with the lower mold assembly to define a mold cavity formed between the convex mold surface and the concave mold surface for manufacturing the headliner assembly therein.  
           [0009]    The headliner assembly comprises a fiberglass mat embedded within a layer of urethane foam forming a contoured substrate having opposing first and second sides. A mold release film is affixed to the first side and an adhesive film is affixed to the second opposing side. A layer of scrim is adhered to the mold release film for providing resiliency and sound absorption to the headliner assembly. A layer of fabric is adhered to the adhesive film for providing a decorative cover to the headliner assembly wherein the headliner assembly is formed of a predetermined contour having areas of various thickness of the urethane foam for providing integrated energy absorption in the headliner assembly. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]    Advantages of the present invention will be readily appreciated as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings wherein:  
         [0011]    [0011]FIG. 1 is a schematic side view showing a molding apparatus utilized in manufacturing the headliner assembly in accordance with the principles of the present invention;  
         [0012]    [0012]FIG. 2 is a partial schematic side view showing the start position of the molding method and apparatus;  
         [0013]    [0013]FIG. 3 is an top view of the portion of the molding apparatus shown in FIG. 2;  
         [0014]    [0014]FIG. 4 is schematic side view showing the molding apparatus with the upper and lower mold assemblies in mating engagement for molding a headliner assembly;  
         [0015]    [0015]FIG. 5 is a sectional view taken along line  5 - 5  of FIG. 4;  
         [0016]    [0016]FIG. 6 is a partially exploded view of the headliner assembly showing the different layers of the headliner assembly in accordance with the principles of the present invention;  
         [0017]    [0017]FIG. 7 is a side view showing the contour of the headliner assembly;  
         [0018]    [0018]FIG. 8 is an enlarged view of the energy absorbing contour in the area A of FIG. 7; and  
         [0019]    [0019]FIG. 9 is a side view of the headliner assembly showing sound absorbing apertures disposed therein. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0020]    Referring to the Figures, wherein like numerals indicate like or corresponding parts throughout the several views, a schematic side view of a molding apparatus  10  used for manufacturing a headliner assembly in accordance with the principles of the present invention is generally shown in FIG. 1. The molding apparatus  10  includes a rigid support frame  12  for supporting an upper mold assembly  14  for vertical movement. The upper mold assembly  14  has a convex mold surface  16  which is shaped in conformance with the desired uppermost configuration for the headliner assembly. The vertical movement of the upper mold assembly  14  can be accomplished by any conventional means. In the preferred embodiment of FIG. 1, the apparatus  10  includes a pair of die press columns  18  coupled to the frame  12  and extending between the upper mold assembly  14  and a die press  20 . The die press  20  actuates the die press columns  18  and the upper mold assembly  14  for movement vertically with respect to the frame  12 . An encoder  22  determines and controls the relative position of the upper mold assembly  14 .  
         [0021]    The molding apparatus  10  further includes a fixed lower track assembly  24  which extends through the frame  12  beneath the upper mold assembly  14 . A lower mold assembly  26  is mounted for horizontal movement on the track assembly  24  by bearings or wheel members  28 . In FIG. 1, the lower mold assembly  26  is shown in its initial start position. The lower mold assembly  26  is movable along the track assembly  24  between the start position and a mold position under the upper mold assembly  14  for cooperation therewith, as shown in FIG. 3. The lower mold assembly  26  includes a concave mold surface  30  which is shaped in conformance with the desired lowermost configuration for the headliner assembly. A pair of spray heads  32 ,  34  are mounted on the frame  12 , above the lower mold assembly  26  in the start position, for transverse movement with respect to the lower mold assembly  26 . The spray heads  32 ,  34  are connected to a source of foamable material, such as liquid urethane, as designated at  36 . A pair of spray heads  32 ,  34  are provided in order to reduce the amount of time to apply the liquid foamable material during the manufacturing process.  
         [0022]    Referring to FIG. 2, the spray heads  32 ,  34  are spaced apart and fixedly mounted on a carriage assembly  36  which is mounted for movement on an upper track assembly  38  fixed to the frame  12  and suspended above the lower mold assembly  26 . That is, the track assembly  38  suspends the spray heads  32 ,  34  and carriage assembly  36  above the lower mold assembly  26  in the start position for application of the liquid foamable material. The upper track assembly  38  includes a pair of parallel track members  40 ,  42  extending transverse, or substantially perpendicular, to the lower track assembly  24  therebeneath. A pair of spray head mounting members  44 ,  46  are each slidably mounted on a respective track member  40 ,  42 , such as by a bearing coupling. The carriage assembly  36  includes a connecting drive nut  48  having internal threads which cooperate with external threads of a drive screw  50 . The drive screw  50  is mounted for rotation on the upper track assembly  38  and extends in parallel relation between the track members  40 ,  42 . The drive screw  50  is rotated at one end by a bi-directional electric motor  52  to effect transverse movement of the carriage assembly  36 , and spray heads  32 ,  34 , on the track assembly  38 . The opposite end of the drive screw  50  is rotatable mounted in a bearing coupling  54  on the track assembly  38 . The bi-directional motor  52  is adapted to alternately rotate the drive screw  50  in opposite directions to effectuate fore and aft movement of the carriage assembly  36  along the upper track assembly  38 . The direction and speed of the motor  52  may be controlled by a controller, or computer.  
         [0023]    Referring to FIG. 3, the first step on the method of manufacturing a headliner assembly in accordance with the present invention includes placing a mold release film  60  onto the concave mold surface  30  of the lower mold assembly  26  in the start position. The film  60  may be held on the concave mold surface  30  by clamps, fasteners, or vacuum pressure. The film  60  provides a barrier to the mold surface  30  from the liquid urethane  64 . A fiberglass mat  62  is then laid onto the mold release film  60 . The fiberglass mat  62  may by any type of fibrous mat including natural fiber. The positioning of the mold release film  60  and fiberglass mat  62  is typically done manually, however, the method may include automated placement of the layer of the film  60  and mat  62  onto the mold surface  30 . The next step includes the spray heads  32 ,  34  applying a spray of liquid foamable material  64 , preferably liquid polyurethane, to form a polyurethane foam layer around the mat  62  over the entire area of the concave mold surface  30 . After the liquid urethane is sprayed onto the mat  62  it begins to crosslink and expand around the mat  62  so that the mat  62  is enclosed within the urethane. A higher volume of urethane is sprayed on area of the mat  62  for forming a greater thickness to portions of the headliner as will be further discussed hereinbelow. Either before, during or after the urethane is sprayed onto the mat  62 , an adhesive film  66  is attached over the convex mold surface  16  of the upper mold assembly  14 , as shown in FIG. 1. The adhesive film  66  may be secured to the upper mold assembly  14  over the convex mold surface  16  by clamps, fasteners or vacuum pressure.  
         [0024]    Shortly after the liquid urethane is sprayed onto the mat  62 , or even during the spraying, the lower mold assembly  26  is rolled along the lower track assembly  24  beneath the upper mold assembly  14 . The die press  20  is then actuated to move the die press columns  18  downwardly and lower the upper mold assembly  14  into mating engagement with the lower mold assembly  26  as shown in FIG. 4. A cavity is formed by the mating engagement of the upper  14  and lower  26  mold assemblies between the convex mold surface  16  and the concave mold surface  30 . The molds  14 ,  26  remain in mating engagement while the urethane continues to expand and fills the cavity between the mold surfaces  16 ,  30 . The cavity, defined by the convex and concave shape of the respective mold surfaces  16 ,  30 , forms the shape of the headliner with dimensions as specified by a particular vehicle design. Additionally, heat and/or pressure may be applied to the upper  14  and/or lower  26  mold assemblies to increase the rate of expansion and formation of the urethane as desired.  
         [0025]    The urethane eventually cures and bonds to the mold release film  60  and adhesive film  66  forming a urethane substrate  68  with the fiberglass mat  62  embedded within the urethane  64 , as shown in FIG. 5. Referring to FIG. 6, subsequent to the forming of the urethane substrate  68 , a layer of fabric  70  is applied to, or laid over, the adhesive film  66 . Heat is applied to activate the adhesive film  66  for bonding the fabric  70  to the substrate  68 . The fabric  70  comprises a layer of woven or non-woven material, such as cloth, vinyl, or leather, which may be foam backed for providing a decorative cover to the interior passenger compartment of the vehicle.  
         [0026]    A layer of scrim  72  is also applied to, or laid over, the mold release film  60  and bonded thereto with web adhesive or an equivalent as is known to one skilled in the art. The scrim  72  comprises a layer of cotton fiber, synthetic fiber, or foam as is known to one skilled in the art, for preventing squeaking noise with the roof of the vehicle when attached thereto. Alternatively, the mold release film  60  may be a laminate of film  60  and scrim  72 . Still further, the mold release film  60  and/or adhesive film  66  may be a prelaminated combo mat including the film  60 ,  66 , scrim  72  and chopped glass.  
         [0027]    Referring to FIG. 6, a partially exploded view of a headliner is shown at  80  as constructed according to the above described method. The fiberglass mat  62  is shown surrounded by, embedded and suspended within the urethane foam  64  forming the urethane substrate  68  to enhance the strength characteristics of the headliner  80 . The mold release film  60  is attached to one side of the substrate  68  and the adhesive film  66  is attached to the other side of the substrate  68 . The fabric  70  is adhered to the adhesive film  66  and the scrim  72  is adhered to the mold release film  60 .  
         [0028]    The thickness of the substrate  68  is inversely proportional to the density of the urethane. Although the amount of liquid urethane  64  applied to the mat  62  can be adjusted according to desired design thickness of the headliner  80 , the narrower cross-section of the substrate  68  will still have higher density than the thicker cross-sections due to the expansion properties of the urethane  64 .  
         [0029]    The exterior dimensions of the headliner  80  and overhead component holes may be cut with a water jet (not shown), however, other conventional methods of cutting such as with a piercing tool will suffice. When edge wrapping of the headliner  80  with the fabric  70  is desired, a pre-cut of the exterior dimensions are made to the substrate  68  prior to applying the fabric  70 . A second cut is made of the fabric  70  leaving enough excess fabric to edge wrap as is known in the art of headliner manufacturing.  
         [0030]    The cross-section of an example contour for the headliner  80  is shown in FIG. 7.  
         [0031]    An alternative method of manufacturing does not require that the lower mold  26  be mobile which allows for the elimination of the lower mold wheels  28 . Therefore, the lower mold  26  is stationary beneath the upper mold  14 . For the alternative method, the liquid urethane  64  is applied to the mold release film  60  and mat  62  which rests on a flat surface and a wet composite is subsequently slid onto the lower mold  26  while beneath the upper mold  14 . The upper mold  14  is actuated into mating engagement with the lower mold  26  by the die press  20  for forming the substrate  68  and the process is continued according to the prior method stated hereinabove.  
         [0032]    The method for manufacturing the headliner  80  provides design benefits for the headliner not available to prior art manufacturing methods. For example, devices, such as foam blocks, sinusoidal plastic inserts, rib cartridges and wire cages are glued to upper surfaces of headliners for absorbing head impact energy. The addition of these devices adds assembly time and significant cost to the price of a headliner assembly. The subject manufacturing method provides the ability to add head impact contours as shown at  82  into the urethane substrate  68  as is represented in FIG. 7. The addition of these contours  82  does not add cost and assembly time to the headliner manufacturing process. The contour and thickness of the urethane substrate  68  can be modified to optimize energy absorption by simply designing the tool cavity accordingly. For example, it is known to those of skill in the art of energy absorption that sinusoidal contours in energy absorbing components provide more energy absorption than does a smooth contour. Sinusoidal contours can be designed into the mold cavity providing the desired energy absorption properties to the headliner assembly without adding additional components to the assembly. A sinusoidal contour  84  is represented best in FIG. 8. Alternate contours such as, for example, a pattern of cavities in the substrate  68  is also known to be effective both for molding and for energy absorption. Alternatively, energy absorbing devices can be inserted into the mold cavity prior to the liquid urethane wherein the urethane will expand around the device securing it onto the substrate  68 . This eliminates the step of gluing the device to the substrate  68 .  
         [0033]    The thickness of the urethane substrate  68  is known to be directly proportional to the overall strength of the headliner  80 . An increase in thickness of the headliner  80  provides efficiency benefits to vehicle manufacturing derived from the strength of the headliner  80 . For example, modern vehicle manufacturing utilizes modular subassemblies such as a headliner assembly having all of the overhead components (i.e. sun visors, assist grips, coat hooks) attached prior to being installed into a vehicle. Current headliner substrate technology, such as tramivex, dry polyurethane and fiberglass is not able to support these overhead components during a modular build operation without cracking and breaking. The urethane substrate  68  of the subject concept can be thickened either locally, or generally, providing the strength as needed for supporting the modular build components.  
         [0034]    The thickness of the urethane substrate  68  can also be optimized for providing structural support to a vehicle roof. For example, gluing the upper surface  86  of the headliner  80  to an underside of a vehicle roof with hot melt glue or an equivalent provides enough structural support to the roof to eliminate structural roof bows. The elimination of the structural roof bows increases vehicle interior space, reduces vehicle mass, and reduces vehicle cost. Utilizing the subject headliner  80  for structural support prevents deflection of the vehicle roof while under a load of up to several hundred pounds.  
         [0035]    To meet vehicle interior acoustic standards, the urethane substrate  14  may include a plurality of apertures  88  pierced into the lower surface  90  as shown in FIG. 9. The apertures  88  deflect sound waves reverberating inside the vehicle interior for reducing the overall sound level therein. The fabric  70  overlays the apertures  88  for preventing the apertures  88  from being visible to the vehicle occupants. A piercing step prior to affixing the fabric  70  to the urethane substrate  68  is added to the headliner manufacturing process for inserting the apertures  88 . However, other methods for adding the apertures  88  are contemplated such as, for example adding pins to the surface of one or both of the upper and lower mold  14 ,  26 .  
         [0036]    The method for manufacturing the headliner  80  explained hereinabove further provides the ability of inserting the overhead components such as assist grips, wiring harnesses, lighting components, and coat hooks into the mold cavity thereby integrating the components into the urethane substrate  68 . This further reduces the complexity of the assembly process and enhances the fit of the components to the headliner  80  by form fitting the substrate  68  to the components when the urethane expands around the components.  
         [0037]    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.