Abstract:
A structural joint configuration is formed in an automotive frame in which the frame members are bent into an angular orientation and joined together to form a structural joint in the automotive frame in which loads imposed on any of the frame members forming the joint will be transferred to and shared with the other frame members in the joint. The structural joint can be configured with as many legs as needed to conform to the number of frame members entering the joint. The frame members can be formed with any cross-sectional shape and from any conventional material or combination of materials. Joining the frame members at the structural joint can be accomplished by welding or by applying adhesives. Load distribution through the frame members forming the structural joint enables the joint to withstand an application of high loads without major cracks or bending at the structural joint.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to an automotive frame member and, more particularly, to a joint configuration for improving performance under crush loading. 
       BACKGROUND OF THE INVENTION 
       [0002]    Federal safety requirements require vehicles to withstand loads on the vehicle roof area for occupant safety and protection. These load requirements, expressed as a percentage of vehicle weight, increase as newer Federal requirements are established. The roof load requirements are intended to simulate loads on the vehicle encountered during a vehicle rollover event. The newer, more demanding Federal requirements force countermeasures, i.e. changes to the structure of vehicle frames, which can ultimately add significant cost and weight to the vehicle. It is essential to minimize the weight of the vehicle, and thus the countermeasures adopted to meet the newer Federal safety requirements, as added weight to the vehicle frame translates into increased load requirements as the requirements are expressed in terms of a percentage of the total vehicle weight. Increasing frame size is, therefore, a “Catch 22” type of situation in that the addition of structure to meet the load requirements of the newer regulations results in increased load requirements that must be resisted by the frame structure to satisfy the Federal requirements. 
         [0003]    One of the challenges in maintaining frame integrity to withstand the crush loads imposed on the roof structure is the formation of the joints between respective frame members. If the joints separate during crush loading, the frame will undergo collapse before the respective frame members are crushed. Accordingly, improvements in the formation of structural joints would present an opportunity for increasing the load carrying capability of the automotive frame structure. 
         [0004]    In U.S. Pat. No. 4,618,163, granted to Franz Hasler, et al on Oct. 21, 1986, the automotive frame is formed with internesting members, including joints that are used to interconnect frame members extending in different directions. In this manner, the respective frame members are tied together by the joint members. The automotive frame in U.S. Pat. No. 4,355,844, issued to Marco Fantini Muzzarelli on Oct. 26, 1982, is made in a similar manner with joint connectors placed to engage frame members extending in different directions to tie the automotive frame together. The joint connectors are formed of three shell elements, two of which are L-shaped and the third may be formed by an independent element. 
         [0005]    A similar space frame construction for an automotive frame is disclosed in U.S. Pat. No. 4,660,345, issued on Apr. 28, 1987, to James Browning, in which thin walled castings are welded together to form a unitary, multiple pipe juncture between series of truss or elongated structural members, forming the vehicle space frame. The space frame concept is expanded in U.S. Pat. No. 5,715,643, granted on Feb. 10, 1998, to Raymond Parkinson, in which a joining system is disclosed for joining automotive chassis members together to form a space frame structure. 
         [0006]    It would be desirable to provide a configuration for forming a joint between frame members in an automotive frame that will improve the load carrying capability of the automotive frame. 
       SUMMARY OF THE INVENTION 
       [0007]    It is an object of this invention to overcome the aforementioned disadvantages of the known prior art by providing a joint configuration for an automotive frame that increases load carrying capabilities. 
         [0008]    It is another object of this invention to provide a universal joint construction for use in an automotive frame that can be formed in multiple leg configurations. 
         [0009]    It is a feature of this invention that the frame members are formed into a joint in which a load imposed one frame member is shared with other frame members forming the joint. 
         [0010]    It is an advantage of this invention that the frame members forming the joint can be bent into any angle to conform to the application of the joint in the automotive frame. 
         [0011]    It is another advantage of this invention that the assembly of the automotive frame is made easier than previously known in the art. 
         [0012]    It is still another advantage of this invention that the joint can withstand high loads by transferring the load from one member within the formed joint to another. 
         [0013]    It is yet another advantage of this invention that the structural joint will not be subjected to cracks and bending when placed under load. 
         [0014]    It is still another feature of this invention that the frame members can be formed with any cross-sectional shape, including tubular members and C-sections. 
         [0015]    It is still another feature of this invention that the frame members can be formed with any wall thickness configuration that is constant or variable over length and cross section, and manufactured through any known process including, but not limited to, hot stamping, cold stamping, hydroforming and extrusion. 
         [0016]    It is yet another feature of this invention that the universal joint can be utilized at substantially any joiner of automotive frame components. 
         [0017]    It is still another feature of this invention that the frame members can be formed of substantially any material or combination of materials in the same joint. 
         [0018]    It is yet another feature of this invention that the legs of the joint can be secured through welding or by adhesives. 
         [0019]    It is a further object of this invention to provide a universal joint configuration for use in an automotive frame that is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use. 
         [0020]    These and other objects, features and advantages are accomplished according to the instant invention by providing a structural joint configuration formed in an automotive frame in which the frame members are bent into an angular orientation and joined together to form a structural joint in the automotive frame in which loads imposed on any of the frame members forming the joint will be transferred to and shared with the other frame members in the joint. The structural joint can be configured with as many legs as needed to conform to the number of frame members entering the joint. The frame members can be formed with any cross-sectional shape and from any conventional material or combination of materials. Joining the frame members at the structural joint can be accomplished by any welding technology or by applying any means of adhesives. Load distribution through the frame members forming the structural joint enables the joint to withstand an application of high loads without major cracks or bending at the structural joint. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0021]    The advantages of this invention will become apparent upon consideration of the following detailed disclosure of the invention, especially when taken in conjunction with the accompanying drawings wherein: 
           [0022]      FIG. 1  is a perspective view of a conventional automotive vehicle frame highlighting the different joints that can be formed in the joint configuration incorporating the principles of the instant invention; 
           [0023]      FIG. 1A  is a cross-sectional view of a representative beam formed with hat-shaped sections; 
           [0024]      FIG. 2  is a perspective view of a joint formed according to the principles of the instant invention with three legs, the cross-sectional shape of the frame members being C-shaped channels; 
           [0025]      FIG. 2A  is a perspective view of the joint shown in  FIG. 2 , but utilizing tubular frame members; 
           [0026]      FIG. 3  is a perspective view of a joint formed according to the principles of the instant invention with four legs, the frame members being formed with C-shaped channels; 
           [0027]      FIG. 4  is a perspective view of an alternative embodiment for a three leg joint formed with three members in a curved configuration; 
           [0028]      FIG. 5  is a perspective view of an alternative embodiment of a four leg joint formed with tubular members; 
           [0029]      FIG. 6  is a schematic elevational view of another alternative embodiment depicting a two-legged joint formed with a connector interconnecting the shaped frame members to form the joint; 
           [0030]      FIG. 7  is a schematic elevational view of a two-legged joint configuration similar to that of  FIG. 6 , but utilizing a connector member that does not have an enlarged central portion; and 
           [0031]      FIG. 8  is a schematic elevational view of a two-legged joint configuration similar to that of  FIG. 7 , but showing an angular orientation of the shaped frame members. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0032]    Referring to  FIGS. 1-5 , a structural frame configuration for an automotive vehicle incorporating the principles of the instant invention can best be seen. Automotive frame members  10  are typically formed from a pair of shaped members  12 ,  13 , often hat-shaped members, such as is shown in  FIG. 1A , that have transversely opposed flanges  15 . To beef up the frame member  10 , the frame member  10  can be provided with an internal reinforcement member  14 , which is typically welded to one of the members  13 . The two shaped members  12 ,  13  can be manufactured in many different forms, including in the way of examples, hat sections, as shown in  FIG. 1A ; C-shaped sections, as shown in  FIG. 2 ; rectangular cell or tubular member, as shown in  FIG. 2A ; half-hexagon; half-circle; arched shape; or any combination of such cross-sectional geometry known to one of ordinary skill in the art. These shaped members  12 ,  13  can be manufactured from any standard material including, in the way of examples, steel, aluminum, composites, nylon and magnesium, and manufactured through any known process including hot-stamping, cold stamping, hydroforming and extrusion. 
         [0033]    The shaped frame sections  12 ,  13  are arranged in opposing relationship to define a cavity therebetween and a frame member  10  that has a substantial depth dimension. Joining such frame members  10  at a joint  20 , as representatively shown in  FIG. 1 , is typically accomplished by welding, through one of known welding technologies, the frame member  10  to a separate joint member, as is reflected in the prior art documents identified above, or by welding flanges or other adjoining surfaces of the respective frame members  10 . These frame members can also be manufactured with a hydroforming process that bends tubular members into required shapes and configurations. 
         [0034]    As is reflected in  FIGS. 2-4 , the joints  20  between such formed frame members  10  can be created by dividing the two shaped members  12 ,  13  at the jointure  20  so that one shaped member  12  extends in one direction to merge with a corresponding shaped member  16  of a frame member  11  with which the joint  20  is to be formed, while the other shaped member is bent to extend in the opposing direction to merge with the corresponding shaped member  16  extending in the other direction from the joint  20 . In this manner, the two frame members  10 ,  11  are merged into one integral joint  20 . 
         [0035]    Actual construction can be accomplished in anyone of several manners, but as an example, the frame member  11  can be formed with a portion of the lower shaped member  13  deleted from the frame member  11  at the location of the joint  20 . The joining frame member  10  can be formed with the two shaped members divided, as depicted in  FIGS. 2 and 2A , bent in opposing directions to mate with the lower shaped member  16  of the frame member  11 , and welded together. Alternatively, the joint  20  could be formed as shown in  FIGS. 2 and 2A , with the two shaped members  12 ,  13  divided from one another and bent in opposing directions, then capped with an upper shaped member  17 . The formed joint  20  could then be welded to correspondingly shaped frame members that would mount to each respective leg  21 - 23  of the joint  20 . 
         [0036]    The angle at which the shaped members  12 ,  13  are bent, identified in  FIGS. 2 and 2A  as α 1  and α 2 , can be any angle required to allow the legs  21 - 23  of the joint  20  to align with the orientation of the frame members  10 ,  11  corresponding to each of the legs  21 - 23 . Furthermore, particularly with hydroforming processes, the respective legs  21 - 23  do not have to be formed in a common plane. Therefore, the joint  20  can be formed, bent and oriented so that the legs  21 - 23  can align with the frame members  10 ,  11  merging at the joint  20 . 
         [0037]      FIG. 2  depicts a representative schematic view of a joint  20  formed with C-shaped sections  12 ,  13  that are edge welded to form frame members.  FIG. 2A  depicts a similar configuration of the joint  20 , but formed with rectangular tubing members  12 ,  13  that are edge welded to form the frame members  10 ,  11 . The use of tubular members  12 ,  13 , as shown in  FIG. 2A , allows a hydroforming process to be utilized to provide a desired shape and orientation of the respective legs  21 - 23 . 
         [0038]    In  FIG. 4 , the three leg joint  20  in which the three legs extend in X Y and Z axes, as opposed to just the X and Y axes as depicted in  FIGS. 2 and 2A , is formed with three members  12 ,  13  and  17  that are separated and bent in a manner that form the three orthogonally extending legs  21 - 23 . 
         [0039]    The bending of the first and second shaped members  12 ,  13  from the first leg into the second and third legs, along with the joining thereto of the third shaped member  17  to the bent portions of the first and second shaped members  12 ,  13 , leaves an interstitial gap  19  at the intersection of the first, second and third shaped members  12 ,  13  and  17 . This interstitial gap  19  can remain an empty void, but could optionally be filled with a material to minimize potential noise emanating from the gap  19 . This damping material (not shown) could be substantially any material, such as a foam, or the exterior of the interstitial gap  19  could be alternatively covered by a welded plate that covers the interstitial gap  19 . 
         [0040]      FIGS. 3 and 5  depict a configuration of the joint  30  in a manner that creates a joint having four legs  31 - 34  projecting in different directions to reflect the merger of three or four frame members at one joint  30 . As noted above with respect to  FIGS. 2 and 2A , the shaped members  12 ,  13  can be formed in any particular shape, such as the C-shaped sections shown in  FIG. 3 , or any of the other aforementioned shapes, or a combination of those shapes. The fourth leg  34  is formed by dividing the shaped members  36 ,  37  and bending them in opposing directions to mate against the adjoining legs  32 ,  33 . Additional legs for the joint  30  can be formed in similar manners by mating against the opposite sides of the joint legs  32 ,  33 , or across the back of the shaped member  17  spanning the legs  32 ,  33 . As with the embodiment of  FIGS. 2 and 2A , the bend angles α 1  through α 5  can be any particular value, as needed to form the joint  30  in a configuration that will match with the corresponding frame members aligning with the respective legs  31 - 34 . As with the embodiment of  FIGS. 2 and 2A , the interstitial gap  19  can be filled with foam or other damping material, or be covered with a plate welded to the corresponding shaped members. 
         [0041]    In  FIG. 5 , the joint  30  is formed by dividing the two shaped members  12 ,  13  and the two shaped members  36 ,  37 , which respectively are entering the joint  30  at angular orientations, and bending the members  12 ,  13 ,  36 ,  37  into an angular deflection that aligns with the corresponding opposing shaped member  12 ,  13 ,  36 ,  37  to form the legs  31 - 34 . For such formed configurations, hydroforming tubular members could be the most advantageous manufacturing process. 
         [0042]    In  FIGS. 6-8 , a two-legged embodiment of the instant invention can best be seen. In this two-legged joint  40 , a pair of shaped frame members  12 ,  13  are joined together at a structural joint by a connector  41  to which the shaped frame members  12 ,  13  are welded after being assembled. The connector  41  can have a central portion  42  shaped uniformly with the shaped members  12 ,  13  to which the connector is joined, so that the welded joint as an aesthetic uniform appearance from one shaped frame member  12  to the other  13 . The connector  41  has a pair of support legs  43 ,  44  projecting in opposing directions from the central portion  42 . The support legs  43 ,  44  are shaped and sized to fit internally within the respective ends of the shaped frame members  12 ,  13  to provide support and reinforcement thereto at the joint  40 . The connector  41  can be linearly or angularly formed as depicted in  FIGS. 7 and 8  to mate appropriately to the orientations of the shaped frame members  12 ,  13  being interconnected to form the joint  40 . As can be seen in the configuration of the connector  41  in  FIG. 6 , as compared to the configuration in  FIGS. 7 and 8 , the connector  41  can be formed with or without the enlarged central portion  42 . The shaped frame members  12 ,  13  are then welded to the connector  41 , as depicted in  FIGS. 6-8 , to form the joint  40 . 
         [0043]    While the shaped members are preferably formed of steel, as noted above, the shaped members can be formed of any appropriate material. Similarly, the preferred method of attaching shaped members together to form the joint  20 ,  30  is to weld the shaped members; however, other methods of attaching the shaped members to one another can be utilized as appropriate with respect to the material being used in the manufacture of the shaped members, including the use of adhesives and thermal and chemical bonding techniques. 
         [0044]    It will be understood that changes in the details, materials, steps and arrangements of parts which have been described and illustrated to explain the nature of the invention will occur to and may be made by those skilled in the art upon a reading of this disclosure within the principles and scope of the invention. The foregoing description illustrates the preferred embodiment of the invention; however, concepts, as based upon the description, may be employed in other embodiments without departing from the scope of the invention.