Abstract:
A cross car beam or other elongated structural member including a series of walled open ended sections fixed end to end in a linear array by having ends joined to respective sides of a series of interposed junction plates. The junction plates may have locator features formed thereon to properly position the respective ends of adjacent sections and to be located in a welding fixture.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional application No. 61/338,963 filed on Feb. 25, 2010, which is hereby incorporated by reference. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    There is a considerable on-going effort to reduce the weight of automobiles in order to improve fuel economy and performance. This includes the various structural elements of the automobile body. 
         [0003]    This effort includes substitution of lighter materials such as aluminum and magnesium for conventionally used steel. 
         [0004]    Another always crucial consideration is cost (both in tooling and production), particularly in times of industry financial stress. 
         [0005]    Magnesium is the lightest metal potentially useable for this application but is relatively expensive and has other problems limiting its use such that it no longer is considered a serious contender, leaving aluminum as the best choice. 
         [0006]    A key major structural component is the cross car beam which is the backbone of the instrument panel in an automobile. This beam extends laterally between the “A” pillars to provide support for various diverse components located at the front end of the passenger compartment, i.e., the steering column, passenger airbag, entertainment/information modules, electronic accessories, and heating and cooling ducting components. Typically various component mounting brackets or supports are provided for the components to be mounted to the cross car beam. 
         [0007]    Such cross car beams have in the past been constructed of formed steel with various mounting support features attached as by welding or with fasteners. 
         [0008]    The trend to reduced weight construction of automobiles has led to attempts to use high pressure die cast aluminum or magnesium for the cross car beam, but these are normally more expensive than steel and not sufficiently lighter to warrant the higher cost. 
         [0009]    It is an object of the present invention to provide a cross car beam constructed of a light weight material such as aluminum and a method of constructing such a structural member. 
       SUMMARY OF THE INVENTION 
       [0010]    The recited object and other objects which can be understood upon a reading of the following specification and claims are achieved by the present invention, in which a series of varying configuration thin walled sections which are separately formed as by extruding, casting, or other process are joined together to form the cross car beam. 
         [0011]    The series of sections are secured together end to end in a linear array by being attached to respective opposite sides of interposed junction plates disposed between respective ends of adjacent sections as by welding or adhesively bonding. 
         [0012]    The junction plates provide transition pieces for connecting the different end shapes of adjacent diverse sections and which also strengthen and stiffen the individual sections to improve the torsional and bending stiffness and strength of the resultant cross car beam. As noted, the sections are formed of thin wall hollow or open sided extrusions, castings or other pieces of different configurations each optimally shaped and located to hold a component to be mounted thereto. 
         [0013]    The handling and welding and/or adhesive bonding steps are preferably performed by suitably programmed robots, such that high quality joints may be achieved at modest cost. The aggregate tooling costs for individual sections is less than the total tooling cost of a convention cross car beam total since the individual sections are smaller than the complete cross car beam and tooling for making extensions is much cheaper, comparatively. 
         [0014]    A lightweight cross car beam according to the invention thus is provided at a reasonable cost. 
         [0015]    Other structural members can be constructed by the method of joining a series of preformed sections end to end with junction plates according to the invention. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a pictorial view of a typical prior art steel cross car beam. 
           [0017]      FIG. 2  is a diagrammatic pictorial view of a cross car beam or other structure according to the present invention. 
           [0018]      FIG. 3  is a fragmentary pictorial representation of a simplified segment of a cross car beam according to the invention showing diversely shaped sections joined together. 
           [0019]      FIGS. 4 and 4A  are pictorial views of respective opposite sides of a junction plate to be incorporated into a cross car beam according to the invention formed with locator features on each side for positioning respective adjacent ends of sections to be joined thereto and to be located in a welding fixture. 
           [0020]      FIG. 5  is a pictorial view of a cross car beam constructed in accordance with the present invention together with fragmentary portions of an automobile body shown in broken lines. 
           [0021]      FIG. 5A  is a reverse pictorial view of the cross car beam shown in  FIG. 5  slightly rotated upwards for clarity. 
           [0022]      FIG. 6  is a fragmentary enlarged pictorial view of a portion of a cross car beam constructed in accordance with the method of the invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0023]    In the following detailed description, certain specific terminology will be employed for the sake of clarity and a particular embodiment described in accordance with the requirements of 35 USC 112, but it is to be understood that the same is not intended to be limiting and should not be so construed inasmuch as the invention is capable of taking many forms and variations within the scope of the appended claims. 
         [0024]    Referring to  FIG. 1 , a traditional cross car beam  10  comprises a heavy gauge steel structure formed by a pair of stampings  12 A, 12 B and a tubular end piece  14  all welded together. The structure cannot be a straight member and must be angled due to typical space restrictions imposed by the design of a car body and the need to support various components at different locations. Separate support brackets and elements are attached as by welding to allow mounting of various supported components such as the steering column, etc. 
         [0025]    According to the present invention, a cross car beam  16  shown in  FIG. 2  or other member is formed by attaching together a series of separately formed and differently configured individual thin walled sections  18 A,  18 B,  18 C,  18 D,  18 E,  18 F, extruded or cast preferably from aluminum. Other processes such as stamping may be used to form the section. 
         [0026]    Each of the sections  18 A- 18 F are attached together in an end to end linear array with a respective intermediate junction plates  20 A,  20 B,  20 C,  20 D,  20 E,  20 F interposed and abutting adjacent ends thereof as shown. 
         [0027]    As indicated in  FIG. 3 , the adjacent ends of sections  18 - 1 ,  18 - 2  and  18 - 2 ,  18 - 3  are welded along their lines of contact  22  defined by the perimeter of the open wall ending of each section with an abutting respective side of intermediate junction plates  20 - 1 ,  20 - 2 . 
         [0028]    An end plate  24  can also be welded to a free end of an end section  18  for reinforcement and stiffening of the section  18 . This is preferably and economically carried out by robotic welders which are very efficient when used for such purposes. 
         [0029]    Similarly, an adhesive bonding robotic operation may alternatively be used to fix the ends to the junction plates  20 . 
         [0030]      FIGS. 4 and 4A  illustrate that one or more of the plates  20  preferably have opposite sides formed with sets of locating features  26 A,  26 B, each receiving the respective end of an abutting section  18  in order to locate the same in readiness for welding or bonding together. 
         [0031]    One or more lightening holes  28  may also be cut into the plates  20  as appropriate. 
         [0032]    In addition, notches  25  or other features may be provided for location of the plates  18  on welding fixtures. 
         [0033]      FIGS. 5 and 5A  depict a typical cross car beam  30  having diverse separately formed sections joined together in an end to end aligned linear array to form a unitary beam, each section optimally configured to provide mounting support for various components such as the steering column, radio/CD player, glove box and connections to the A pillars A and hinge posts H. 
         [0034]    The outboard A pillar connections can be provided by cast sections  32 A,  32 B. 
         [0035]    A steering column extruded support platform  34  is connected to the left A pillar casting  32 A with hollow box connector extrusions  36 ,  38 . A support box extrusion  39  can be welded to the fire wall F. 
         [0036]    A junction plate  40  connects the extrusion  36  to extrusion  38  welded to their juxtaposed ends. 
         [0037]    A second junction plate  42  connects extrusion  38  to extruded platform  34 . 
         [0038]    A junction plate  44  is welded to the opposite end of the platform  34 , and also to a hollow box connector extrusion  46 . 
         [0039]    The connector extrusion  46  also has a junction plate  48  welded to its opposite end attached to one end of a panel extrusion  50 . 
         [0040]    One end of the panel extrusion  50  is supported by a forwardly extending hollow square tube extruded strut  52  welded to the extrusion  46  and plate  48 , while a second forwardly extending extruded hollow square tube strut  54  is welded to the panel extrusion  50 . 
         [0041]    A lower support for the panel extrusion  50  is provided by a weldment formed by square tubular extrusions  56 ,  58 ,  60 ,  62 ,  64 , extrusions  56 ,  58  welded to the lower front face of the panel extrusion  50 , extrusions  62 ,  64  welded to the floor plan tunnel T. 
         [0042]    The right end of the panel extrusion  50  is welded to a junction plate  56 , which has its opposite face welded to the left end of a glove box frame extrusion  68 . 
         [0043]    A glove box frame is completed by elongated low pressure castings  70 ,  72  and by the right A pillar connection casting  32 B, which is also connected to the right end of the glove box frame extrusion  68  by being welded to a junction plate  74 . 
         [0044]    A horizontal support square tube extrusion  76  is welded to junction plate  74  and extrusion  68 . 
         [0045]    The welded or bonded connections  80  as seen in  FIG. 6  can advantageously be carried out by a robot welder quickly and at low cost. 
         [0046]    Thus, a unitary lightweight cross car beam can be provided with sections located and optimally configured to mount and support the various components, which provides a strong structural member for achieving an enhanced structural integrity of the automobile body. 
         [0047]    This method can also be applied to construct such other complex structural members such as seat frames in automobiles, etc.