Patent Publication Number: US-2005140168-A1

Title: Door trim panel assembly having integrated soft-touch aesthetic feature and method of manufacturing same

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates, generally, to a door trim panel assembly for automotive vehicle interiors. More specifically, the present invention relates to a door trim panel assembly having an integrated soft-touch feature and method of manufacturing same.  
      2. Description of the Related Art  
      Interior trim components for automobiles commonly include a trim panel mounted to a vehicle door. Typically, automotive door trim panels often have designated cushioned areas in the armrest or bolster area to impart a tactile, comfortable area commonly referred to as a “soft-touch area.” The soft-touch area of a door trim panel includes components manufactured independent from the door trim panel per se and subsequently assembled thereto.  
      Traditionally, these components include a plurality of pre-formed components such as a rigid substrate, foam intermediate layer and coverstock, among others. The rigid substrate is often constructed from a polymer and manufactured via an injection molding process. In this case, a mold cavity must be tooled to conform to the predetermined dimensions of the soft-touch area. The intermediate layer is typically a pre-formed flexible-foam or elastomeric pad of varying thickness. The intermediate layer may be purchased in sheet form and subsequently trimmed to correspond to the shape of the rigid substrate. While neither of these pre-formed components is visible from the vehicle interior, they still require assembly, manufacture, and handling separate from actually assembling the soft-touch area, resulting in a significant cost factor associated with this effort.  
      The top surface of the soft-touch area is commonly referred to as “coverstock.” The coverstock presents a “class-A” surface that is visible from the vehicle interior when installed and a “class-B” surface that contacts the foam intermediate layer. The coverstock may be constructed from any number of materials to provide a durable yet aesthetic surface layer for the soft-touch area. By way of example, coverstock materials such as leather, cloth, or high-grade polymers, which often impart a textured class-A surface simulating the grain of leather, may be employed to cover the soft-touch area. Because the coverstock must be durable and provide an aesthetically pleasing class-A surface, it is often the most costly component of the door trim panel when compared to the rigid substrate and foam intermediate layer. Further, the coverstock requires secondary handling to trim the material to correspond to the predetermined shape of the soft-touch area.  
      In addition to the cost associated with manufacturing the pre-formed components of the soft-touch area of a door trim panel, there are additional cost factors associated with assembling these components to a door trim panel. More specifically, the armrest often requires extensive labor to stretch the coverstock, sew and/or glue the components together. The additional handling and assembly efforts required to assemble a door trim panel armrest or bolster having a soft-touch area may also give rise to defective or substandard assembly, resulting from improper fitting of the components or misalignment during the sewing and/or gluing process. In any event, the secondary handling and assembly as well as the production of substandard products result in increased costs to produce a door trim panel assembly with a soft-touch area.  
      There are several different known processes that may be employed to manufacture a door trim panel component having an integrated soft-touch aesthetic feature such as a bolster and/or armrest. By way of example, processes involving low pressure molding, structural reaction injection molding, and vacuum forming have all been employed to reduce the costs associated with assembling the substrate, intermediate foam layer and coverstock to produce a door trim panel assembly having an integrated soft-touch aesthetic feature. These processes involve securing the coverstock to the substrate and subsequently placing a foam intermediate layer therebetween.  
      However, each of the above-identified processes require assembly of the coverstock, intermediate layer, and substrate which also requires additional, secondary handling. More importantly, each of the above-identified processes employ a coverstock which is associated with the higher part cost, and increased assembly and secondary handling to manufacture a door trim panel having an integrated soft-touch aesthetic feature. Furthermore, each of the above-identified processes may result in the production of a door trim panel having and irregular/misshapen soft-touch area.  
      While the door trim panels having an integrated soft-touch area of the type known in the related art have generally worked for their intended purposes, there remains a need in the related art to reduce the number of steps required to manufacture a vehicle door trim panel assembly incorporating a soft-touch area. Further, there remains a need in the art to reduce the costs associated with manufacturing a vehicle door trim panel assembly incorporating a soft-touch area. In addition, there remains a need for a vehicle door trim panel assembly that includes an integrated soft-touch area having improved quality. Finally, there remains a need in the art for a vehicle door trim panel assembly that provides a consistent, desirable, class-A surface that is aesthetically pleasing.  
     SUMMARY OF THE INVENTION  
      The present invention overcomes the disadvantages in the related art in door trim panels for vehicles and generally fulfills a need in the art for a method of manufacturing a door trim panel assembly having an integrated soft-touch area for improved aesthetic and ergonomic door trim panel quality. To this end, the method of the present invention includes actuating a core within a mold cavity so as to partition at least one area of the mold cavity to prevent a first molten thermoplastic material from completely filling the mold cavity. A first molten thermoplastic material having a predetermined density is then injected into a mold cavity so as to fill the mold cavity thereby forming a structural element. The core is then retracted from within the mold cavity to provide at least one secondary void within the mold cavity. A second molten thermoplastic material having a density less than the predetermined density of the first molten thermoplastic material is then injected into said secondary void of the mold cavity to form at least one soft-touch area bonded to and adjacent at least a portion of the structural element.  
      Accordingly, one advantage of the present invention is that it provides an integrated soft-touch area while a door trim panel is formed in a mold and thereby reduces the steps necessary to manufacture the vehicle door trim panel assembly.  
      Another advantage of the present invention is that it provides an integrated soft-touch area during manufacture of the door trim panel assembly that eliminates quality issues relating to positive alignment during later assembly of a soft-touch area.  
      Another advantage of the present invention is that it provides a monolithic soft-touch area to reduce cushion variation within the soft-touch area for improved aesthetic quality of the vehicle interior.  
      Still another advantage of the present invention is that it provides a door trim panel assembly having a soft-touch feature that is co-molded with a trim panel component that simplifies the manufacturing process, thereby reducing the costs associated therewith.  
      Other objects, features, and advantages of the present invention will be readily appreciated, as the same becomes better understood, after reading the subsequent description taken in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a fragmentary environmental view of a vehicle including a door trim panel assembly having an integrated soft-touch aesthetic feature of the present invention;  
       FIG. 2A  is a perspective view illustrating the molding process employed to manufacture a door trim panel assembly having an integrated soft-touch feature of the present invention;  
       FIG. 2B  is a perspective view of the mold with the door trim panel assembly receiving an integrated soft-touch feature of the present invention shown in phantom;  
       FIG. 2C  is a perspective view of the mold and door trim panel assembly having an integrated soft-touch feature of the present invention; and  
       FIG. 3  is a cross-sectional view of a component of a door trim panel having an integrated soft-touch aesthetic feature of the present invention.  
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      A vehicle that employs the door trim panel assembly of the present invention is generally indicated at  10  in  FIG. 1 , where like numbers are used to designate like structure throughout the figures. The vehicle  10  includes a vehicle body generally indicated at  12 , having a hood  14 , windshield  16 , roof  18 , and side window  20 . The vehicle  10  further includes a vehicle door, generally indicated at  22 . The vehicle door  22  is adapted to be pivotally mounted to the vehicle body  12  and includes components such as a window  24  and a side mirror panel  26  for covering the side rear view mirror mounts (not shown). The vehicle  10  further includes an interior generally indicated at  28 . The interior  28  includes a plurality of trim panels, such as a dashboard  30 , that provide an aesthetic and ergonomic environment for the vehicle occupant. However, those having ordinary skill in the art will appreciate that the interior  28  of a vehicle  10  includes components such as seats, a center console, steering wheel as well as other components not illustrated but generally known in the art.  
      Another trim panel employed within the interior  28  of a vehicle  10  is the modular door trim panel assembly of the present invention which is generally indicated at  32 . As illustrated in  FIG. 1 , the trim panel assembly  32  is mounted to a driver&#39;s side door  22 . However, those having ordinary skill in the art will appreciate that it may be mounted to any vehicle door. By way of example, the trim panel assembly  32  of the present invention may be mounted to a passenger side door or a hatchback door. Further, the door trim panel assembly  32  may also be molded to any predetermined shape to accommodate adjacent components of the vehicle  10 , such as the window  24  or side mirror panel  26 .  
      Referring to  FIG. 1 , the door trim panel assembly  32  of the present invention includes a plurality of trim panel components generally indicated at  34 , each having a surface that is visible from the interior  28  of a vehicle  10 . As illustrated throughout the figures, the trim panel components  34  of the trim panel assembly  32 , include a door latch assembly  36  to facilitate ingress and egress to and from the vehicle interior  28 , a map pocket  38  to retain various articles such as maps, compact discs and other articles, and a window control  39  to facilitate movement of the window  24  of the vehicle door  22 . Those having ordinary skill in the art will appreciate that the modular door trim panel assembly  32  of the present invention may include any number of other components such as a speaker cover, cup holder, etc as well as fewer components, depending on the styling of the interior  28  of a vehicle  10 .  
      As illustrated in the figures, the door trim panel assembly  32  includes a substrate generally indicated at  40 . The substrate  40  provides a surface upon which the trim panel components  34  may be mounted. The substrate  40  includes a first side  42  defining a class-A surface  44  that is visible from the interior  28  of an automotive vehicle  10  and a second side  46  that is opposite the first side  42  and that defines a class-B surface  48  adjacent the vehicle door  22 . The class-A surface  44  may incorporate a pattern or texture, such as the grain of leather, to improve the aesthetic quality of the vehicle interior  28 .  
      The door trim panel assembly  32  of the present invention further includes a structural element, generally indicated at  50 , that accommodates additional trim panel components. For example, the door trim panel assembly  32  includes an armrest generally indicated at  52 , and a predetermined surface  54  that is visible from the interior  28  of a vehicle  10 . The armrest  52  is defined by a plurality of sidewalls  56 ,  58  having a shape that corresponds to the designated style and area of a particular vehicle interior  28 , while the predetermined surface  54  defines a bolster area  55 . Those having ordinary skill in the art will appreciate that the sidewalls  56 ,  58  may include any predetermined shape to compliment the aesthetic features within the interior  28  of a vehicle  10 . By way of example, the armrest  52  shown in  FIG. 1  includes elongated and arcuate sidewalls  56 ,  58  for improved aesthetic and ergonomic quality of the interior  28  of a vehicle  10 . The sidewalls  56 ,  58  also include a recess  60  to receive the door latch assembly  36  and an aperture  62  to receive the window control  40 . Those having ordinary skill in the art will appreciate that the sidewalls  56 ,  58  may include any number of recesses  60  or apertures  62  to accommodate other trim panel components to improve the aesthetic and/or ergonomic quality of the interior  28  of a vehicle  10 .  
      Further, the armrest component  52  and the bolster component  54  may also include a soft-touch area  64  bonded to and formed adjacent at least a portion of an underlying structural element  50 . A generic representation of a soft-touch area  64  bonded to and formed adjacent at least a portion of the structural element  50  is shown in  FIG. 3 . Specifically, the soft-touch area  64  is bonded to and formed adjacent the structural element  50  of either the armrest  52  or the bolster  54 . The soft-touch area  64  of the door trim panel assembly  32  includes a class-A surface  66  that not only eliminates the need for a coverstock material, but also eliminates the need for an intermediate layer as well, thereby reducing the likelihood of deformation or an otherwise irregular cushion-like feel as a result of a substandard intermediate layer and thereby improve the aesthetic quality of the vehicle interior  28 . Referring to  FIG. 1 , a soft-touch area  64  is bonded to the sidewall  56  of the armrest  52  including the door latch assembly  36  as well as the sidewall  58  including the window control  40 . However, those having ordinary skill in the art will appreciate that the soft-touch area  64  may be employed anywhere along the sidewalls  56 ,  58  of the armrest so as to be visible from the interior of a vehicle and may present any color or pattern.  
      As noted above, armrest  52  and bolster  54  components of the door trim panel assembly  32  of the present invention are formed via an injection molding process. In this way, the structural elements  50  of the components  52 ,  54  are essentially co-molded with the soft forming elements of the soft-touch area  64  while the door trim panel substrate  40  is at least partially formed in a mold cavity to reduce the costs associated with manufacturing a component of the door trim panel assembly  32 . Generally speaking, the manner in which the structural element  50  receives the soft-touch area  64  streamlines the manufacturing of a door trim panel assembly  32  by eliminating the need for a coverstock and intermediate cushion layer, as well as other secondary handling processes.  
      The method of the present invention includes the steps of injecting a first molten thermoplastic material having a predetermined density into a mold cavity having an actuated core. When actuated, the core partitions a portion of the mold cavity so as to prevent the first thermoplastic material from completely filling the mold cavity. The first thermoplastic material may include any rigid forming material suitable for use in an injection mold. By way of example the material employed may include nylon, polypropylene, acrylonitrile butadiene styrene (ABS), polyvinyl chloride (PVC) or thermoplastic olefin (TPO) or other rigid forming material.  
      The first molten thermoplastic material forms a structural element  50  in the mold cavity, defining a component  52 ,  54  of the door trim panel assembly  32 . This structural element  50  may correspond either to the armrest component  52  or the bolster component  54 . In either event, upon the lapse of a predetermined amount of time that is specific to the material and mold process conditions, the core is retracted to define a secondary void within the mold cavity. A second molten thermoplastic material is then injected into the secondary void of the mold cavity while the structural element  50  remains tacky. The second molten thermoplastic material includes a density less than that of the first molten thermoplastic material and is bonded to the structural element  50  within the mold cavity. Thus, the second molten thermoplastic material has a softer, more tactile and comfortable feel once it has solidified and cooled than that of the first molten thermoplastic material. Those having ordinary skill in the art will appreciate that any material adapted for use in an injection mold that provides the desired soft-touch feel may be employed. Specifically, the second thermoplastic material imparts a soft-touch area  64  that is bonded to and adjacent at least a portion of the structural element  50 .  
      Another method to manufacture a component of the door trim panel assembly is illustrated in  FIGS. 2A-2C . This method involves providing a mold, generally indicated at  68 , having a first and second die halves  70 ,  72  and a core, generally indicated at  74 , moveably supported relative to the die halves  70 ,  72 . This method employs the same co-molded methodology as above-identified. The core  74  is disposed between the first and second die halves  70 ,  72  to define a first and second mold cavity  76 ,  78 . A first molten thermoplastic material having a predetermined density is injected into the first mold cavity  76  thereby forming a structural element  50 . Again, the structural element  50  formed in the first mold cavity  76  may define either the armrest component  52  or the bolster component  54  and the first molten thermoplastic material has the same characteristics as discussed above.  
      Following a predetermined lapse of time to permit the structural element  50  to partially cure within the first mold cavity  76 , the core  74  is moved relative to the first and second die halves  70 ,  72  to define a second mold cavity  78 . In the preferred embodiment illustrated here, the core  74  is moved in a rotating manner to form the second mold cavity  78  and a second molten thermoplastic material, having a density less that the predetermined density of the first thermoplastic material, is injected therein from a source (S). As noted above, the second molten thermoplastic material has a softer, more tactile and comfortable feel once it has solidified and cooled than that of the first molten thermoplastic material. The second injected molten thermoplastic material forms at least one soft-touch area  64  that is bonded to and disposed adjacent at least a portion of the structural element  50  of the formed component.  
      As illustrated in  FIGS. 3A-3C , the core  74  includes a first surface  80  and a second surface  82  opposite the first surface  80 . The first and second surfaces  80 ,  82  of the core  74  are virtually identical to provide efficient manufacture of door trim panel assembly  32 . Specifically, while the second molten thermoplastic material is injected into the second mold cavity  78 , the first molten thermoplastic material is injected relative to the opposing core surface in the first mold cavity  76 . However, those having ordinary skill in the art will appreciate that the core  74  need not include two surfaces  80 ,  82  to employ the above-described method.  
      The present invention reduces the steps necessary to manufacture a vehicle door trim panel assembly  32  having a soft-touch area  64  by eliminating the need for a coverstock. Further, the present invention bonds the soft-touch area  64  to the door trim panel component  52 ,  54  while in a mold  68 , thereby eliminating quality issues relating to positive alignment during later assembly of a soft-touch area  64 . Still further, the soft-touch area  64  is injected onto the door trim panel component  52 ,  54  to provide a uniform feel, thereby reducing cushion variation within the soft-touch area  64  and eliminating the need for an intermediate foam layer to impart a soft-touch area  64 .  
      The present invention has been described in an illustrative manner. It is to be understood that the terminology that 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. Therefore, within the scope of the appended claims, the present invention may be practiced other than as specifically described.