Patent Publication Number: US-2007119101-A1

Title: Internal reinforcement structure for automotive vehicle door panels

Description:
BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The invention relates to automotive vehicle door panel constructions in which an outer door panel assembly is characterized by enhanced structural stiffness.  
      2. Background Art  
      A vehicle door construction for contemporary automotive vehicles typically comprises a plurality of structural panels. Window glass channels secure a glass window pane at forward and rearward edges of the window pane while accommodating movement of the window glass between a closed position and an open position. A door outer structure is disposed on one side of the window glass and a door inner structure is disposed on the opposite side. The door outer structure typically includes a belt reinforcement that extends fore and aft from a forward door opening location to a rearward door opening location. The belt reinforcement typically is situated proximate to the outer side of the window glass and the window glass supporting glass channels. The door outer structure includes also an outer panel situated on the outboard side of the belt reinforcement.  
      The span between the front end and the rear end of the side door outer structure typically has no transverse support for transmitting loads from the belt reinforcement into the stiffer inner door structure on the inside of the window area. The outer door structure span is approximately equal to the width of the vehicle door opening. Because of its relatively long span, the side door outer structure typically is characterized by low stiffness since stiffness is inversely proportional to the length of the span between end supports.  
      Prior art vehicle door constructions do not permit a practical way to compensate for the low stiffness of the side door outer structure because of a lack of space between the side door outer structure and the window glass support channels.  
      Because of the low stiffness of the vehicle side door outer structure, which includes the outer panel and the belt reinforcement, access to the interior of the vehicle during burglaries can be accomplished by deflecting the side door outer structure using special tools for forcing the side door outer structure outwardly relative to the inner side door structure. This creates a space that allows an intruder to activate and release a door locking mechanism situated in the interior of the door between the side door inner structure and side door outer structure.  
     SUMMARY OF THE INVENTION  
      It is an objective of the invention to reduce the vulnerability of a contemporary vehicle side door to unlawful entry by reducing the span between belt reinforcement securements at the forward portion and the rearward portion of the belt reinforcement, thereby increasing the stiffness of the side door outer structure. The securements are relatively close to the forward and rearward edges of the window glass.  
      The securements for the belt reinforcement comprise at least one connector bracket that engages the belt reinforcement and a glass channel, one glass channel being located at the forward edge of the window glass and another glass channel being located adjacent the rearward edge of the window glass.  
      If two connector brackets are used, one end of each connector bracket is fixed permanently to an adjacent glass channel. This may be done by spot welding or riveting. The other end of each glass channel is located near one of the mechanical securements to the belt reinforcement.  
      A mechanical connection between each connector bracket and the belt reinforcement may be a screw or a similar mechanical fastener, which may be released when there is a need for replacing an original equipment manufacturer&#39;s (OEM) outer panel and belt reinforcement subassembly. Access to this mechanical fastener is made by providing a tool access opening in each of the side door inner structural panels. Thus, the fastener can be applied and released using a suitable tool that may be inserted through the openings.  
      During assembly of the door structure, the side window glass, in the initial assembly steps, will not have been assembled in place. It is possible, therefore, to access the fastener with a suitable tool. The access will not be prevented by the window glass, which is assembled in the vehicle side door construction in a later step in the assembly process.  
      In accordance with one feature of the invention, the connector bracket may be a symmetrical part so that it can be located on both the leading edge of the door opening and the rear edge of the door opening. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is an isometric plan view of an automotive vehicle side door;  
       FIG. 2  is a partial plan view of a portion of the door of  FIG. 1  in proximity to the forward edge of the door opening with the side door outer structure removed;  
       FIG. 3  is a partial plan view of a forward portion of the inner door panel structure;  
       FIG. 4  is a partial plan view of a rear portion of the inner door panel structure;  
       FIG. 5  is a partial cross-sectional view of the door structure seen in  FIG. 1  as viewed from the plane of section line  5 - 5  of  FIG. 1 ;  
       FIG. 6  is an enlarged cross-sectional view of the front portion of the door structure seen in  FIG. 5 ;  
       FIG. 7  is a partial enlarged cross-sectional view of the rearward portion of the view of  FIG. 5 ; and  
       FIG. 8  is a detailed schematic illustration of a connector bracket located at a forward location of the door structure as seen in the cross-sectional view of  FIG. 5 . 
    
    
     PARTICULAR DESCRIPTION OF AN EMBODIMENT OF THE INVENTION  
       FIG. 1  is an isometric plan view of a front left side door outer panel assembly, including an appropriately contoured outer door panel  10 , a rear portion  12 , an upper portion  14  and a forward portion near front window frame portion  16 . The side window glass is indicated at  18 .  
      The complete side door outer structure is not illustrated in  FIG. 1 . The side door inner structure also is lacking. The area of interest, for purposes of the subsequent description of the invention, is indicated in  FIG. 1  by the area enclosed by dotted lines, as shown at  20 .  
       FIG. 2  shows the side door inner structure as viewed from the exterior of the vehicle with the outer side door structure removed. A window glass channel  22  is secured to the outboard surface of panel  24 , which forms a part of the side door inner structure. A structural connection between the glass channel  22  and the panel  24  can be formed by welding, although other fastening techniques could be used, including riveting.  
      As will be described subsequently with reference to  FIGS. 5 and 6 , the glass channel  22  has a U-shaped cross section. It provides a support for the front edge of the window glass  18 , as the window glass is raised and lowered between the side door inner structure and the side door outer structure. A connector bracket, which will be described more particularly with reference to  FIG. 6 , is shown in  FIG. 2  at  26 . The bracket  26  provides a secure mechanical connection between the glass channel  22  and the belt reinforcement, which forms a part of the side door outer structure as will be described with reference to  FIGS. 6 and 7 .  
      Bracket  26  includes an opening  28  for accommodating a fastener that mechanically connects the connector bracket  26  and the glass channel  22  to the side door outer structure.  
       FIG. 3  is a partial plan view of the front edge portion of the side door inner structure, which includes an innermost panel  30  that may support a trim panel (not shown). Panel  30  is provided with an access opening  32 , which is aligned with the opening  28  in the connector bracket  26  seen in  FIG. 2 . The panel  30  is provided with a window glass opening, which has a sill portion  34  and a front edge window glass frame portion shown at  36 , which forms a part of the forward window frame  16  seen in  FIG. 1 .  
      As seen in  FIG. 2 , the panel  24  is secured preferably by spot welds, shown at  38  and  40 , to the front edge of a structural door frame  42 , which is hinged to the vehicle body structure.  
       FIG. 4  shows the rearward portion of the panel  30  adjacent the rearward edge of the window glass opening. A tool access opening  44  is formed in the rearward portion of the panel  30  to permit tool access to a fastener that will be described with reference to  FIG. 7 . Intermediate side door inner structure panel  46 , seen in  FIG. 6 , is situated between the inner panel  30  and the panel  24  of the side door inner structure. Panel  46  is connected by welding or other fastening techniques to the panel  24 , as indicated schematically at  48  in  FIG. 6  and at  50  in  FIG. 7 .  
      A tool access opening  52  is formed in the panel  46  and a tool access opening  54  is formed in the panel  24 , as indicated in  FIG. 6 . The access openings  32 ,  52  and  54  are aligned with a fastener, such as a threaded fastener  56 .  
      Fastener  56  is received in an opening  58  formed in reinforcement member  60 , which extends longitudinally fore-and-aft in the space between outer panel  10  and panel  24  of the side door inner structure.  
      The outer panel  10  is welded at its margin to the forward edge region of the inner panel  30 , as shown at  62  in  FIG. 6 . Reinforcement member  60  is secured permanently, such as by welding, to the outer panel  10 , as schematically illustrated at  64  in  FIG. 6  and at  66  in  FIG. 7 . The inner panel  30  is secured at its forward margin to the outer panel  10  by welding, as shown at  68  in  FIG. 6  and at  70  in  FIG. 7 .  
      The rearward region of the door panels seen in  FIG. 7  includes a second fastener, such as a threaded fastener  72 , received in an opening  74  in the rearward portion of the reinforcement member  60 . The threaded fastener  72  is aligned with opening  44  in inner panel  30 , with opening  76  at the rearward region of inner panel  46  and with an access opening  78  in the rearward portion of inner panel  24 . The rearward portion of panel  24  is secured by welding at its margin to the inner panel  30 , as seen at  80 .  
      The reinforcement member  60  extends through the door structure from the forward edge to the rearward edge in the general region of interest, indicated at  20  in  FIG. 1 . Connector bracket  26 , which is generally of L-shape, has a leg with an opening  28  through which the threaded fastener  56  extends, as seen in  FIG. 6 . A tool can be inserted through the access openings  32 ,  52  and  54  from the inner side of the side door inner structure to secure the bracket  26  in place. A second leg of the bracket  26  extends in a generally perpendicular direction with respect to the adjacent leg. It is secured at  84  to a side of the window glass U-shaped channel  22 . The U-shaped channel, as mentioned previously, is secured to the panel  24  of the side door inner structure. Therefore, the reinforcement member  60  is firmly secured to the inner door structure to form a robust and stiff door assembly.  
      The window glass  86  has its forward margin received in the window glass channel at  26 . During the assembly procedure, however, the glass  86  is not in place. Therefore, the fastener  56  can be accessed to secure the connector bracket  26  to the glass channel  22 .  
      At the rearward edge of the side door inner structure, a second connector bracket of generally L-shape is provided, as shown at  88 . It has an opening for receiving a fastener  72 , whereby the fastener  72  secures the bracket  88  to the panel  60 . Right angle portion  90  of the bracket  88  is secured to one side of a rearwardly positioned glass channel of U-shape, as shown at  92 . The glass channel  92  is secured to the panel  24 , as schematically shown at  94 . That connection is located out of the plane of the cross section line  5 - 5  seen in  FIG. 1 .  
      The glass channel  26  is secured to the panel  24  at the forward edge region of the side door inner structure, as shown schematically at  96  in  FIG. 6 . Thus, the connector bracket  88  complements the stabilizing characteristic of the connector bracket  26  to provide a stable, robust connection between reinforcement member  60  and the inner door structure at both the forward edge region and the rear edge region of the side door assembly.  
       FIG. 5  illustrates a reduction in the effective span between the supports for the reinforcement member for the construction of the present invention in comparison to a conventional span for a vehicle side door structure. The reduced span within the window projection of the inner structure of the present invention is substantially less than the conventional span, as indicated in  FIG. 5 . This increases the stiffness of the door assembly and reduces the deflection of the reinforcement member  60  from the plane of the glass  86  when a force is applied to the reinforcement member, thereby making it much more difficult for an intruder to gain access to the vehicle interior.  
      The best span between the fasteners  56  and  72  is computed as follows:  
      δ=Fl 3 [X]EI, where  
      δ=deflection that should be minimized;  
      F=force in a direction perpendicular to the plane of the window glass;  
      l=the length of the span between the fasteners  56  and  72 ;  
      E=the modulus of elasticity of the reinforcement member; and  
      I=the second moment of inertia.  
      The term “X” is a load case factor for free end supports for a beam. The value for “X” is empirically determined depending upon how the beam is supported and the load is applied. It is obtained using a stimulated computer model using a free body loading of an end supported beam.  
      Although an embodiment of the invention has been disclosed, it will be apparent to a person skilled in the art that modifications may be made without departing from the scope of the invention. All such modifications and equivalents thereof are intended to be included within the scope of the following claims.