Abstract:
A structural joint assembly for a vehicle is provided with a first thermoplastic composite member having a protrusion containing fibrous material. A reinforcement member is provided with a receptacle for mating engagement with the protrusion. A second thermoplastic member is mounted to the first thermoplastic member over the protrusion such that the reinforcement member is provided between the first thermoplastic member and the second thermoplastic member but not adhesively bonded or overmolded therebetween. A method of manufacturing a structural joint assembly and a structural joint assembly manufactured by a method are disclosed. The methods include molding a first thermoplastic member with a protrusion with fibrous material and a second thermoplastic member. A reinforcement member has a receptacle and is mounted to the first thermoplastic member. The receptacle is retained by the protrusion without adhesive bonding or overmolding. The second thermoplastic member is joined to the first thermoplastic member.

Description:
BACKGROUND 
       [0001]    1. Technical Field 
         [0002]    Various embodiments relate to reinforced thermoplastic structural joint assemblies for vehicles. 
         [0003]    2. Background 
         [0004]    Automotive vehicles typically utilize a variety of joints to assemble a vehicle from smaller components and subcomponents. Joints may be flexible to allow relative movement between two or more articles or rigid to allow little or no movement between two or more articles. In many cases, strong joints that can be manufactured reliably with good durability are desired so that the overall structure will carry the specified loads over a long period of time. 
       SUMMARY 
       [0005]    In one embodiment, a structural joint assembly is provided with a first thermoplastic member having a protrusion containing fibrous material. A reinforcement member has a receptacle formed therein for mating engagement with the protrusion. A second thermoplastic member is mounted to the first thermoplastic member over the protrusion such that the reinforcement member is provided between the first thermoplastic member and the second thermoplastic member but not adhesively bonded or overmolded therebetween. 
         [0006]    In another embodiment, a method of manufacturing a structural joint assembly is disclosed. A first thermoplastic member is molded having at least one protrusion with fibrous material provided therein. A second thermoplastic member is molded. A reinforcement member is provided and is sized to be received by the first thermoplastic member for a mating engagement with the at least one protrusion. The reinforcement member is mounted the first thermoplastic member such that the receptacle of the reinforcement member is retained by the protrusion without adhesive bonding or overmolding. The second thermoplastic member is joined to the first thermoplastic member at the at least one protrusion such that the reinforcement member is provided between the first thermoplastic member and the second thermoplastic member thereby increasing load capacity. 
         [0007]    In yet another embodiment, a structural joint assembly manufactured by a method is provided. A first thermoplastic member is molded having at least one protrusion with fibrous material provided therein. A second thermoplastic member is molded. A reinforcement member is provided and is sized to be received by the first thermoplastic member for a mating engagement with the at least one protrusion. The reinforcement member is mounted to the first thermoplastic member such that the receptacle of the reinforcement member is retained by the protrusion without adhesive bonding or overmolding. The second thermoplastic member is joined to the first thermoplastic member at the at least one protrusion such that the reinforcement member is provided between the first thermoplastic member and the second thermoplastic member thereby increasing load capacity. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  is an exploded perspective view of an embodiment of a structural joint assembly; 
           [0009]      FIG. 2  is another perspective view of the structural joint assembly of  FIG. 1  illustrated partially assembled; 
           [0010]      FIG. 3  is a perspective view of the structural joint assembly of  FIG. 1 ; 
           [0011]      FIG. 4   a  is an elevation view of an embodiment of a portion of a structural joint assembly; 
           [0012]      FIG. 4   b  is an elevation view of another embodiment of a portion of a structural joint assembly; 
           [0013]      FIG. 4   c  is an elevation view of another embodiment of a portion of a structural joint assembly; 
           [0014]      FIG. 4   d  is an elevation view of yet another embodiment of a portion of a structural joint assembly; 
           [0015]      FIG. 4   e  is an elevation view of still another embodiment of a portion of a structural joint assembly; 
           [0016]      FIG. 4   f  is an elevation view of still another embodiment of a portion of a structural joint assembly; 
           [0017]      FIG. 4   g  is an elevation view of yet another embodiment of a portion of a structural joint assembly; and 
           [0018]      FIG. 4   h  is an elevation view of yet another embodiment of a portion of a structural joint assembly. 
       
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
       [0019]    As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for the claims and/or as a representative basis for teaching one skilled in the art to variously employ the present invention. 
         [0020]    With reference to  FIGS. 1-3 , a structural joint assembly is illustrated and generally referenced by numeral  10 . The structural joint assembly  10  can be employed to join two or more components together and when assembled, can bear a load. Generally, the structural joint assembly  10  is not flexible but may allow for at least some amount of movement between the two or more components joined by the structural joint assembly  10 . 
         [0021]    In one non-limiting example, the structural joint assembly  10  is adapted to be mounted to a vehicle roof panel and a vehicle frame to join the vehicle roof panel and the vehicle frame together. The structural joint assembly  10  may be employed for any structural or semi-structural thermoplastic application, as discussed below. Of course, any shape and size for the structural joint assembly  10  is contemplated within the scope of the embodiments of the present invention. 
         [0022]    Referring now to  FIG. 1 , the structural joint assembly  10  is depicted in an unassembled orientation during a manufacturing process. The structural joint assembly  10  is provided with a first thermoplastic member  12 , a reinforcement member  14  and a second thermoplastic member  16 . 
         [0023]    The first thermoplastic member  12  is adapted to support a first component and the second thermoplastic member  16  is adapted to support a second component. The first thermoplastic member  12  and the second thermoplastic member  16  can be joined together as a structural joint  10  to join the first component to the second component. The first thermoplastic member  12  and the second thermoplastic member  16  can be joined together to attach components that may be mounted on or formed into the first thermoplastic member  12  and the second thermoplastic member  16 . 
         [0024]    The reinforcement member  14  is provided between the first thermoplastic member  12  and the second thermoplastic member  16  to increase load capacity of the structural joint assembly  10 . 
         [0025]    The first thermoplastic member  12  and the second thermoplastic member  16  can be made out of a thermoplastic material or a thermoplastic composite material. Non-limiting examples of the thermoplastic material include polypropylene and nylon. In at least one embodiment, the first thermoplastic member  12  and the second thermoplastic member  16  are injection molded out of the thermoplastic material or the thermoplastic composite material. Of course, the first thermoplastic member  12  and the second thermoplastic member  16  can be made out of identical or differing materials. 
         [0026]    Creating the first thermoplastic member  12  and the second thermoplastic member  16  out of the thermoplastic material or the thermoplastic composite material can result in a relatively small weight for the structural joint assembly  10 , while maintaining low production and/or assembly costs when compared to metal joint assemblies. The first thermoplastic member  12  and the second thermoplastic member  16  each have structural strengths determined by material properties of the materials used to form the first thermoplastic member  12  and the second thermoplastic member  16 . Fibrous material can be added to the thermoplastic material to create a thermoplastic composite material before formation of the first thermoplastic member  12  and the second thermoplastic member  16  to increase the structural strength. In one embodiment, a glass fiber material is injection molded along with the thermoplastic material or the thermoplastic composite material. Two non-limiting examples of a thermoplastic material having fibrous material are glass reinforced nylon or glass reinforced polypropylene. The configuration of the each of the first thermoplastic member  12  and the second thermoplastic member  16  allow for generally even distribution of the fibrous material throughout each of the first thermoplastic member  12  and the second thermoplastic member  16 . 
         [0027]    To achieve increased structural strength for the structural joint assembly  10  in addition to utilization of fibrous material in the first thermoplastic member  12  and the second thermoplastic member  16 , the reinforcement member  14  is oriented between the first thermoplastic member  12  and the second thermoplastic member  16 . 
         [0028]    The reinforcement member  14  may be made out of a metal material having a high load capacity relative to the thermoplastic material or thermoplastic composite material forming the first thermoplastic member  12  and the second thermoplastic member  16 . In one embodiment, the metal reinforcement member  14  is fabricated out of a steel material. In another embodiment, the metal reinforcement member  14  is created out of an aluminum material. Of course, the metal reinforcement member  14  may be made out of a metal composite material. In at least one embodiment, the reinforcement member  14  is made out of a plastic or reinforced plastic (composite). Any suitable generally metal material, plastic or reinforced plastic having relatively high load capacity when compared to the thermoplastic material or thermoplastic composite material can be used to form the reinforcement member  14 . 
         [0029]    Prior art reinforcement members are overmolded or bonded in prior art joint assemblies. The overmolding process creates many concerns including design concerns, product function concerns, and cost concerns. The reinforcements must be held in place during the molding process, which is difficult, costly and time consuming. Additionally, the reinforcements need to be heated prior to molding so that the metal does not act as a heat sink and cause high stresses in the thermoplastic, adding difficulty, cost and time to the process. In addition, in reinforced thermoplastics, maintaining consistent fibrous material around the reinforcement is difficult to control and the region around the reinforcement may have a lower concentration, resulting in a weak joint. The bonding process between the metal reinforcement and the thermoplastic creates concerns about preventing surface contamination, maintaining proper bond thickness, and providing confidence in the strength of the resultant bond. Consequently, a manufacturing process that would allow for load transfer between a metal reinforcement and the thermoplastic that does not require either overmolding or bonding would be highly beneficial. Thus, the structural joint assembly  10  can be formed without overmolding or bonding while providing a high load capacity structural joint assembly  10 . 
         [0030]    As illustrated, the first thermoplastic member  12  is provided with protrusions  18 . The protrusions  18  can be integrally formed within the first thermoplastic member  12 . The protrusions  18 , as illustrated, have a circular shape to create a large surface area for the protrusions  18 . 
         [0031]    Corresponding with the protrusions  18  formed in the first thermoplastic member  12  are receptacles  20  formed in the reinforcement member  14 . The receptacles  20  can be integrally formed with the reinforcement member  14  or can be formed in a subsequent process after initial formation of the reinforcement member  14 . 
         [0032]    In  FIG. 2 , the joint assembly  10  is illustrated in a partially assembled orientation during manufacturing. As illustrated, the reinforcement member  14  can be mounted onto the first thermoplastic member  12  so that the protrusions  18  align with the receptacles  20 . The contact between the protrusions  18  and the receptacles  20  retain the reinforcement member  14  on the first thermoplastic member  12  so that the reinforcement member  14  does not need to be held onto the first thermoplastic member  12 . 
         [0033]    The protrusions  18  may be generally flush with the surface of the reinforcement member  14 , as illustrated. In another embodiment, the protrusions  18  extend beyond the surface of the reinforcement member  14  to facilitate joining the second thermoplastic member  16  to the first thermoplastic member  12 , which is discussed further below. 
         [0034]    In  FIG. 3 , the structural joint assembly  10  is illustrated upon completion of the manufacturing process. After mounting the reinforcement member  14  to the first thermoplastic member  12  (shown in  FIG. 2 ), the second thermoplastic member  16  is mounted to the first thermoplastic member  12 . The reinforcement member  14  is generally provided between the first thermoplastic member  12  and the second thermoplastic member  16 . 
         [0035]    In one embodiment, the second thermoplastic member  16  is joined to the first thermoplastic member  12  at the plurality of protrusions  18  that are exposed through the receptacles  20  in the reinforcement member  14 . The second thermoplastic member  16  can be joined to the first thermoplastic member  12  through thermoplastic welding along contact regions between the first thermoplastic member  12  and the second thermoplastic member  16 . The contact regions correspond to the locations of the protrusions  18 . Thermoplastic welding includes, but of course is not limited to, vibration welding, ultrasonic welding, and laser welding. 
         [0036]    The structural joint assembly  10  illustrated in an assembled orientation in  FIG. 3  is less expensive to manufacture than prior art assemblies of equivalent structural load capacity since the metal is not bonded to the thermoplastic and an overmolding process is not required. Additionally, molding the first thermoplastic member  12  and the second thermoplastic member  16  would be less complicated and less expensive since shut-offs would not be required to prevent resin from flowing onto portions of the metal that need to be free from polymer. Furthermore, creating the joint assembly  10  in the manner described herein is more likely to result in adequate fiber distribution of the fibrous material in the protrusions  18 , which can create a stronger joint assembly  10  than what is possible in an overmolded configuration. Finally, this method of manufacturing allows the assembly to be designed and manufactured with a slip plane that allows the components of the assembly to grow and shrink independently without inducing warpage in the assembly. 
         [0037]    In at least one embodiment, illustrated in  FIGS. 1-3 , the first thermoplastic member  12  has a channel  22  defined by a pair of protruding surfaces  24 . The channel  22  is recessed within the first thermoplastic member  12  so that the reinforcement member  14  can be nested within the channel  22 . 
         [0038]    The second thermoplastic member  16  may be joined to the first thermoplastic member  12  along the pair of protruding surfaces  24 . In another embodiment, the protruding surfaces  24  are additional protrusions and/or flanges to provide additional surface area to join the first thermoplastic member  12  to the second thermoplastic member  16 . 
         [0039]    As depicted in  FIG. 1 , flanges  26  may be integrally formed with each of the first thermoplastic member  12  and the second thermoplastic member  16 . The flanges  26  may be employed to join the structural joint assembly  10  to components. The flanges  26  may allow the joint assembly  10  to be utilized to join two or more materials so that the joint assembly  10  is surrounded by the two or more materials so that the joint assembly  10  is not viewable. Of course, any shape, size and amount for the flanges  26  are contemplated within the scope of the embodiments of the present invention. 
         [0040]    The joint assembly  10  may be utilized in any structural or semi-structural thermoplastic application in the automotive field, including but not limited to polycarbonate glazings, composite seats, thermoplastic liftgate/tailgate constructions, front-end modules. In at least one embodiment, the joint assembly  10  is utilized in an automotive vehicle application such that the joint assembly  10  is not externally viewable by an occupant so that the joint assembly  10  can have surface defects that are not visible to the occupant. Of course, the joint assembly  10  may be utilized in any structural or semi-structural thermoplastic application given the ever increasing use of thermoplastics in semi-structural applications. 
         [0041]    With reference now to  FIGS. 4   a - 4   g , a plurality of embodiments depicting the reinforcement member  14  mounted to the first thermoplastic member  12  are illustrated. 
         [0042]    In  FIG. 4   a , multiple polygonal shaped protrusions  18  are depicted along with corresponding polygonal shaped receptacles  20 . In one embodiment, the protrusions  18  and the receptacles  20  are further defined as rectangles. The protrusions  18  and the receptacles  20  may have rounded corners for ease of production. 
         [0043]    In  FIG. 4   b , multiple triangular shaped protrusions  18  are illustrated along with corresponding triangular shaped receptacles  20 . As illustrated, the protrusions  18  and the receptacles  20  may abut the pair of protruding surfaces  24 . In at least one embodiment, the protrusions  18  form a continuous surface with the pair of protruding surfaces  24 . 
         [0044]    In  FIG. 4   c , multiple polygonal shaped protrusions  18  are shown along with corresponding polygonal shaped receptacles  20 . In the illustrated embodiment, the protrusions  18  and the receptacles  20  are further defined as rectangles. The protrusions  18  and the receptacles  20  may have rounded corners for ease of production. 
         [0045]    In  FIG. 4   d , multiple irregular shaped protrusions  18  are depicted along with corresponding irregular shaped receptacles  20 . The protrusions  18  and the receptacles  20  may have rounded corners for ease of production. 
         [0046]    Referring to  FIGS. 4   e - g , multiple circular shaped protrusions  18  are illustrated along with corresponding circular shaped receptacles  20 . Of course, any amount and location for the protrusions  18  and corresponding receptacles  20  are contemplated within the scope of the embodiments of the present invention. 
         [0047]    With reference now to  FIG. 4   h , protrusions  18  are formed in the first thermoplastic member  12  and different sized receptacles  20  are formed in the reinforcement member  14 . At least one receptacle  20  may be sized to receive at least one of the protrusions  18  so that the reinforcement member  14  is secured to the first thermoplastic member  12 . One or more receptacles  20  may be oversized relative to the protrusions  18  to allow for thermal growth of the first thermoplastic member  12  since the first thermoplastic member  12  may have a different expansion rate than the reinforcement member  14 . The oversized receptacles  20  may each have a length that is greater than a length of the protrusions  18  while having a width that allows for contact between the protrusions  18  and receptacles  20 . 
         [0048]    As illustrated, one receptacle  20  is sized to receive one protrusion  18  and two receptacles  20  are oversized compared to the protrusions  18 . The oversized protrusions  20  allow for thermal growth of the first thermoplastic member  12  in directions indicated by arrows provided proximate the first thermoplastic member  12 . In another embodiment, one receptacle  20  is sized to receive one protrusion  18  at one end of the first thermoplastic member  12  with two oversized protrusions  20  to allow for thermal growth in only one direction, opposite the end with the fitted protrusion  18  and receptacle  20 . Of course, any combination of receptacles  18 , fitted protrusions  20  and oversized protrusions  20  are contemplated within the scope of the embodiments of the present invention. 
         [0049]    While embodiments of the invention have been illustrated and described, it is not intended that these embodiments illustrate and describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention.