Abstract:
A vehicle door assembly is provided that includes a retainer that secures to a door body panel, specifically, to the door inner panel, and is configured such that a door trim component or components may be secured to the retainer, rather than directly to the door trim panel. Door trim components of lightweight materials may be used, with the retainer providing the structural integrity required for securement to the door inner panel. Because it is not a visible component in the assembled door, the same retainer design may be used for doors of different models in a given vehicle platform, with different door trim components of different materials or styles consistent with the different models secured to identical retainers.

Description:
TECHNICAL FIELD 
       [0001]    The invention relates to a door trim panel assembly for a vehicle door and a method of assembling same. 
       BACKGROUND OF THE INVENTION 
       [0002]    Vehicle doors are complex assemblies that typically include a door outer panel visible from outside of the vehicle, a door inner panel, and a plurality of door trim panel components secured to the door inner panel inward of the door inner panel (i.e., inboard of, on the side of the door inner panel facing the passenger compartment). The door trim panel components therefore must be structurally able to securely attach to the door inner panel, while also presenting to the customer as an aesthetically pleasing surface. Numerous validation studies are necessary to ensure that each of the components of the vehicle door assembly interfit with one another and meet durability standards. 
       SUMMARY OF THE INVENTION 
       [0003]    A vehicle door assembly that satisfies desired aesthetics while minimizing engineering validity tests is desired. Fuel economy concerns also drive the need for a door assembly that is lightweight, while providing sufficient structural integrity. These competing goals are met by providing a retainer that secures to the door panel, specifically, to the door inner panel, and is configured such that door trim component or components may be secured to the retainer, rather than directly to the door trim panel. Because it is not a visible component in the assembled door when the door is closed, the same retainer design may be used for doors of different models in a given vehicle platform, with different door trim components of different materials or styles consistent with the different models secured to identical retainers. 
         [0004]    Because only the retainer is directly secured to the door panel, the retainer will require significant structural strength, but lighter weight materials may be used for the door trim component(s), thus providing fuel economy advantages. For example, the retainer may be a filled polypropylene, while the trim component(s) may be a natural fiber. Natural fibers are typically difficult to secure to sheet metal, and may not provide a consistent sealing interface. However, the retainer of filled polypropylene is able to fulfill these functions. 
         [0005]    Because the retainer and door panel may be common components across multiple vehicle models of a given platform, the costs associated with validity testing of the retainer and its interface with the door panel is a shared cost spread across the multiple vehicle models, and is lower than the cost of testing a different retention apparatus for each separate model. 
         [0006]    Accordingly, a method of assembling a vehicle door includes mounting a first door trim component of a first door of a first vehicle type to a first retainer configured to surround an outer periphery of the first door trim component by inserting the periphery into a first channel formed by the retainer. The method further includes mounting a second door trim component of a second door of a second vehicle type to a second retainer configured to surround an outer periphery of the second door trim component by inserting the periphery of the second door trim component into a second channel formed by the second retainer. The first and second retainers are substantially identical, but the first and the second door trim panels are of different materials. The retainer may be injection molded while the door trim component may be compression molded. Furthermore, the door trim component may be formed by layering a natural fiber substrate layer with a foam layer and an outer skin layer, a “cut-and-sew” layer, or the like. A negative or positive vacuum formed outer skin layer, a polypropylene-based foam layer, and a natural fiber substrate layer may be secured to one another and to the retainer by compression molding, with heat of the natural fiber substrate layer acting to melt the adjacent layers and bond the layers to one another. 
         [0007]    The above features and advantages and other features and advantages of the present invention are readily apparent from the following detailed description of the best modes for carrying out the invention when taken in connection with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is a schematic side illustration of a door assembly that includes a multi-piece retainer and additional structural components; 
           [0009]      FIG. 2  is a schematic side illustration of a door trim panel; 
           [0010]      FIG. 3  is a schematic side illustration of a portion of a door handle; 
           [0011]      FIG. 4  is a schematic side illustration of a portion of an armrest assembly; 
           [0012]      FIG. 5  is a schematic side illustration of another portion of the armrest assembly of  FIG. 4 ; 
           [0013]      FIG. 6  is a schematic perspective illustration of yet another portion of the armrest assembly of  FIGS. 4 and 5 ; 
           [0014]      FIG. 7  is a schematic side illustration of the door assembly of  FIG. 1  including the retainer and additional structural components assembled to the door trim panel of  FIG. 2 ; 
           [0015]      FIG. 8  is a schematic cross-sectional view of the door assembly of  FIG. 7  taken at the lines  8 - 8 ; 
           [0016]      FIG. 9  is an enlarged schematic cross-sectional view of an end portion of  FIG. 8 ; 
           [0017]      FIG. 10  is an enlarged schematic cross-sectional view of an opposing end portion of  FIG. 8 ; 
           [0018]      FIG. 11  is a schematic cross-sectional view of the door assembly of  FIG. 7  taken at the lines  11 - 11 ; 
           [0019]      FIG. 12  is an enlarged schematic cross-sectional view of an end portion of  FIG. 11 ; 
           [0020]      FIG. 13  is an enlarged schematic cross-sectional view of an opposing end portion of  FIG. 11 ; 
           [0021]      FIG. 14  is a schematic perspective illustration of a one-piece retainer; 
           [0022]      FIG. 15A  is a schematic perspective illustration of a multi-piece door trim panel assembly for use with the one-piece retainer of  FIG. 14 ; 
           [0023]      FIG. 15B  is a schematic perspective illustration in exploded view of door trim components for use with the trim panel assembly of  FIG. 15A ; 
           [0024]      FIG. 15C  is a schematic perspective illustration in exploded view of trim plates for use with the trim components of  FIG. 15B ; 
           [0025]      FIG. 15D  is a schematic perspective illustration in exploded view of an armrest assembly for use with the trim panel assembly of  FIG. 15A ; 
           [0026]      FIG. 16  is a schematic cross-sectional view of a door assembly including the door trim panel assembly of  FIG. 14 , taken at the lines  16 - 16  of  FIG. 14 , secured to the one-piece retainer of  FIG. 14 , with the one-piece retainer secured to a door inner panel; and 
           [0027]      FIG. 17  is a flow diagram illustrating a method of assembling vehicle doors. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0028]    Referring to the drawings, wherein like reference numbers refer to like components throughout the several views,  FIG. 1  shows a door assembly  10  that includes a door inner panel  12 , shown only in phantom, and a multi-piece retainer including a lower retainer  14 A and an upper retainer  14 B. The lower retainer  14 A includes integral fastener support portions  15 . A speaker cover  16  is illustrated as well as a trim support  18 . The retainers  14 A,  14 B, the speaker cover  16 , the trim support  18  may all be a filled polypropylene material, such as a glass or talc-filled polypropylene or a thermoplastic olefin polypropylene-based compound. Such materials exhibit sufficient strength to be secured to a sheet metal component, such as door trim panel  12  and provide support to trim components, as described below. Additionally, such materials lend themselves to injection molding. 
         [0029]    Referring to  FIG. 2 , a door trim component in the form of a one-piece door trim panel  22  is illustrated. The door trim panel  22  may be a multi-layer component, including a relatively low mass substrate or base layer formed from natural fiber, a foam layer on the base layer, and a decorative skin or cut-and-sew layer on the foam layer and forming the viewing surface  24  (into the page) of the trim panel  22 . Such multiple layers are illustrated with respect to the door assembly of  FIG. 16 . As used herein, a “cut-and-sew” layer is a layer of multiple pieces sewn together that shows the sewn seams. Referring to  FIG. 1 , the speaker grille  16  mounts in an opening  26  formed in the door trim panel  22  of  FIG. 2 . Additional decorative material, such as decorative strips (not shown), may be mounted to the door trim panel  22  as well. 
         [0030]    Referring to  FIG. 3 , a door handle support  28  may also be injection molded and added to the natural fiber substrate of door trim panel  22 . The door handle support  28  mounts to an opening  30  formed in the door trim panel  22  of  FIG. 2 . Referring to  FIG. 4 , an armrest trim component  32  is formed from a compression-molded, low mass natural fiber substrate. A “cut-and-sew” surface layer may be applied to the natural fiber substrate. The armrest component  32  is secured to the door trim panel  22  with fastener openings  34  aligned with fastener openings  36  and opening  38  aligned with opening  40  to allow a door handle (not shown) to extend therethrough. Referring to  FIGS. 5 and 6 , an injection-molded armrest component  42  formed from an acrylonitrile-butadiene-styrene copolymer-based (ABS) plastic is configured to be secured at an opening  43  formed in the door trim panel  22 . Referring to  FIG. 6 , a cut-and-sew skin layer  44  may then be applied over the armrest component  42  before it is secured to the door trim panel  22 . 
         [0031]    The upper and lower retainer  14 A and  14 B are configured to be injection molded. The retainers  14 A,  4 B do not form part of the show surface of the door. Thus, more expensive tooling, such as die inserts typically used to form an undercut for attachment features, are not required to form the retainers  14 A,  14 B. 
         [0032]    Referring to  FIG. 7 , the door trim assembly  10  is shown from a vantage point outboard of the door assembly  10 , i.e., with any door body panels, such as door inner panel  12 , overlaying the structure shown. As further described below, the door trim panel  22  is secured to the retainers  14 A,  14 B, and the lower retainer  14 A is secured to the door inner panel  12  (best shown in  FIGS. 8 and 9 ). In  FIG. 7 , the door inner panel  12  is shown only in phantom as it would be attached to the retainer  14 A forward of the view shown (i.e., overlaying the retainer  14 A and door trim panel  22 ). The upper retainer  14 B is secured to a window frame, not shown. The speaker cover  16  and trim support  18  are also secured to the door trim panel  22 . 
         [0033]    Referring to  FIG. 8 , the lower retainer  14 A is shown secured to the door inner panel  12  (shown in fragmentary view). A fastener  47 , shown only in phantom in  FIG. 9 , is housed in a cage  48  formed in each of the fastener support portions  15  of the retainer  14 A. The fastener  47  may be of a bird beak-type or other type with flexible legs that may be inserted through an aligned opening  49  in the inner door panel  12 . 
         [0034]    As best shown in  FIGS. 9 and 10 , the lower retainer  14 A is formed with a recessed channel  50  in which a periphery  52  of the door trim panel  22  is retained when the door trim panel  22  is secured to the lower retainer  14 A. The retainer  14 A is also formed with a rib  54  adjacent the channel  50  that supports the door trim panel  22 . The door trim panel  22  is secured to the retainer  14 A at a contact interface  51  by bonding, whether adhesive bonding or otherwise, or vibration or heat welding. 
         [0035]    Referring to  FIG. 10 , the retainer  14 A has a substantially flat surface  56  adjacent the channel  50  that is configured to contact an elastomeric seal  58  secured to an automotive B-pillar  60  when the door assembly  10  is placed in a closed position, as is understood by those skilled in the art. The surface  56  is provided so that the seal  58  may contact the retainer  14 A rather than the door trim panel  22 , as it is difficult to provide a sealing surface on a component made of natural fiber materials, such as the door trim panel  22 . 
         [0036]    Referring to  FIGS. 11 and 12 , the upper retainer  14 B has a channel  62  in which the door trim panel  22  is supported. The door trim panel  22  is secured to the retainer  14 A at a contact interface  53  by bonding, whether adhesive bonding or otherwise, or vibration or heat welding. The upper retainer  14 B is secured to a window frame  68  at several different locations by extending fasteners through openings  70  (selected ones of which are numbered in  FIG. 7 ) formed in the upper retainer  14 B into aligned openings (not shown) in the window frame  68 . 
         [0037]    Referring to  FIG. 14 , an alternative embodiment of a one-piece retainer  114 , which may be referred to as a retainer ring, is illustrated. The retainer  114  is a filled polypropylene material, such as a glass or talc-filled polypropylene or a thermoplastic olefin polypropylene-based compound. Such materials exhibit sufficient strength to be secured to a sheet metal component, such as door inner panel  112  of  FIG. 16 , and provide support to trim components, as described below. Additionally, such materials lend themselves to injection molding. 
         [0038]    Referring to  FIG. 15A  multiple door trim components including a lower door trim panel  122 , and upper trim panel  123  and an insert panel  125  are illustrated. The upper trim panel  123  is bonded, welded, and/or heat staked to the lower door trim panel  122  along an upper portion  126  thereof. The insert panel  125  is bonded or heat staked to a mid-portion of the lower door trim panel  122 . The lower door trim panel  122 , upper trim panel  123  and insert panel  125  may be multi-layer compression molded components, with substrate layers of ABS, polypropylene, TPO, a filled polypropylene, a lofted glass or a lofted natural fiber material. A cut-and-sew layer or a skin layer may be applied over the substrate layers for an aesthetically-pleasing viewing surface. Referring to  FIG. 15B , additional door trim components including a first component  130  of a lofted polyethylene fiber and a second component  132  of a compression-molded sheet polypropylene are configured to be secured to the door trim panel  122  as well. A trim plate  134  and a speaker grille  136  mount to the opening  140  in the door trim panel  122 . Referring to  FIG. 15C , various trim plates are provided for application to the assembled trim components of  FIGS. 15A and 15B , including a nylon trim plate  142 , a trim plate  144  that may be ABS with a film or paint layer, or alternatively may be wood or metal, depending on the vehicle model. Finally, a third trim plate  146  is shown that may be ABS with a film or paint layer. 
         [0039]    Referring to  FIG. 15D , a multi-piece armrest assembly includes a base  148  of glass-filled polypropylene, and additional glass-filled polypropylene components  151 ,  152 . A polyurethane foam layer  154  is applied above the base  148 , and a skin  156  of polyurethane or leather is then applied over the layered components  148 ,  151 ,  152 ,  154 . An armrest trim component  158  of ABS with a paint or film layer is then applied to the skin  156  or the foam layer  154 . 
         [0040]    The door trim panel  122  is secured to the retainer  114  by inserting a peripheral edge into a recess, as described with respect to  FIG. 16 . The retainer  114  is secured to a door inner panel  112 , as shown in  FIG. 16 . The integrity of the connection between the retainer  114  and the door trim panel  122  need only be validated once, and identical retainers  114  can then be used with various trim components across multiple vehicle model types that utilize the same door trim panel  122 . 
         [0041]    Referring to  FIG. 16 , a cross-sectional view taken at the lines  16 - 16  of  FIG. 14  shows the door trim panel  122  assembled to the retainer  114 , which in turn is assembled to a door inner panel  112 , to form in part a door assembly  110 . The door trim panel  122  includes a skin layer  170 , a foam layer  172  and a natural fiber substrate layer  174 . The skin layer  170  is bonded to the foam layer  172 , which in turn is bonded to the natural fiber substrate layer  174 . Natural fiber substrate insert layers  176 ,  178  are bonded to one another and to the substrate layer  174 . The insert layers  176 ,  178  are supported in a recess or channel  152  of the retainer  114 . The heat stake  180  is heated and melts to the adjacent components (portion  179  and layer  176 ). A fastener  147  supported by the retainer  114  is secured through an opening in the door inner panel  112  after the door trim panel  122  is secured to the retainer  114 . The insert layers  176 ,  178  allow the layers  172 ,  174  with skin  170  to appear above the retainer  114 , for styling purposes. Alternatively, the inserts  176 ,  178  could be eliminated, with the layers  170 ,  172 ,  174  placed in the recess  152 . In that case, a portion of layer  174  may extend downward to support heat stakes. Instead, a portion  179  of substrate layer  176  dips down to support a heat stake  180  inserted therethrough. The panels  122  may be bonded or screwed, adhered or heat-welded to the retainer  114 . 
         [0042]    The retainer  114  has a substantially flat surface  182  adjacent the recess  152  that is configured to contact an elastomeric seal  184  secured to an automotive B-pillar  186  when the door assembly  110  is placed in a closed position, as is understood by those skilled in the art. 
         [0043]    Referring to  FIG. 17 , a flow chart illustrates a method  200  of assembling vehicle doors. The method  200  begins with step  202 , injection molding substantially identical retainers, such as an inventory of retainers identical to retainer  114  of  FIG. 14  that is configured to surround the outer periphery of a first door trim panel such as door trim panel  122  of  FIG. 15A . The method further includes step  204 , compression molding door trim components, such as the foam layer  172 , natural fiber substrate layer  174  and insert layers  176 ,  178  of door trim panel  122 , and similar layers of upper trim panel  123  and insert panel  125  of  FIG. 15A . Next, in step  206 , the first door trim panel  122  is formed by layering the natural fiber substrate layer  174 , the foam layer  172  and the outer skin layer  170 . Next, in step  208 , a second door trim panel is formed with different compression molded door trim components with the same or different natural fiber substrate layers and outer skin layers for a door of a second vehicle type. For example, the second door trim panel may be the alternative to door trim panel  122  discussed above, in which insert layers  176 ,  178  are eliminated and layers  179 ,  172 ,  174  are placed in recess  152 . In step  210 , the first door trim panel  122  is then mounted to a first of the retainers  114  by inserting a periphery of the door trim panel  122  into a first channel  152  formed by the retainer  114 . In step  212 , the second door trim panel is mounted to a substantially identical retainer  114  by inserting a periphery of the second door trim panel into a channel  152  of the retainer  114 . Thus, identical retainers are used in assembling doors of different vehicle types having different door trim components. 
         [0044]    Either or both of the mounting steps  210  and  212  may be by compression molding the various components of the door trim panel to the retainer. For example, natural fiber substrate layer or layers  174 ,  176 ,  178 , and a negative or positive vacuum formed outer skin layer  170  can be compression molded to the filled polypropylene injection molded retainer  114  in a single compression molding step. The elevated temperature of the natural fiber substrate layer  174  will melt the polypropylene in adjacent foam layer  172  and/or skin layer  170  as well as the substrate of the retainer  114  so that the various components of the door trim assembly  110  are secured to one another in the compression molding step. 
         [0045]    While the best modes for carrying out the invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention within the scope of the appended claims.