Patent Publication Number: US-2006016078-A1

Title: Method for manufacturing a reinforced structural component, and article manufactured thereby

Description:
RELATED APPLICATIONS  
      This application claims priority of U.S. Provisional Patent Application Ser. No. 60/586,009 filed Jul. 7, 2004, entitled “Method of Inserting Structural Support Member in Roll-Formed Part” and U.S. Provisional Patent Application Ser. No. 60/588,118 filed Jul. 14, 2004, entitled “Reinforcement for a B-Pillar of an Automotive Vehicle.” 
    
    
     FIELD OF THE INVENTION  
      This invention relates generally to the manufacture of reinforced structural components such as frame members for motor vehicles. More specifically, the invention relates to a method for incorporating a support member in such a component. In particular, the invention relates to a process for incorporating a reinforcing support member in a roll-formed component.  
     BACKGROUND OF THE INVENTION  
      The structural integrity of the passenger and cargo compartments of a motor vehicle relies upon the use of support pillars and other frame members. These structural components require a combination of high strength and light weight. Furthermore, in order to provide for the dissipation of energy in the event of a crash, these components should exhibit controlled and reliable deformation properties. The prior art originally utilized pillars and other structural components which comprise tubular or channel-like members of various cross-sectional configurations. However, the art subsequently turned to structural components having separate support members, also referred to reinforcement inserts, disposed therein. In some instances, these support members were inserted into pillars and the like after fabrication. For example, prior art U.S. Pat. Nos. 5,219,197 and 6,406,077 show methods wherein a support is inserted into the interior of a fabricated beam. Another approach is shown in U.S. Pat. No. 5,385,375 wherein a body of foamable polymeric material is injected into the interior volume of a beam and permitted to expand to form a polymeric insert. In another approach shown in U.S. Pat. No. 6,733,040, a two-piece beam is utilized, and an insert is placed therein and the two separate beam portions are then joined together.  
      These prior art approaches are difficult to implement since they require that an insert be placed into the interior of a closed beam, or they require that an insert be installed into a two-part beam which process requires subsequent joining of the beam components. Such processes are not compatible with high speed, and in some instances, continuous, manufacturing processes which are generally favored for the fabrication of such components. Therefore, there is a need for a method for manufacturing reinforced pillars, frame members, and other structures, which method is simple to implement and compatible with high-speed fabrication processes such as roll forming.  
      As will be explained in detail hereinbelow, the present invention provides a method for the fabrication of reinforced structures such as beams, pillars, and the like. The method of the present invention does not require that an insert be placed into a closed profile of a finished beam, nor does it require the use of multipart beams. As will be explained in detail hereinbelow, the present invention temporarily affixes a reinforcing support member to a body of material at an intermediate stage in its processing, and this combination is subsequently subjected to further processing to form a single part beam member having a reinforcing support member fixedly retained thereby. The method of the present invention may be readily implemented in conjunction with a high speed, preferably continuous, roll-forming process. These and other advantages of the present invention will be apparent from the drawings, discussion and description which follow.  
     BRIEF DESCRIPTION OF THE INVENTION  
      Disclosed herein is a method for manufacturing a reinforced structural component. In a first step of the method a body of sheet material, such as a body of sheet steel, is subjected to a first forming operation which shapes it into an intermediate structural member. The intermediate structural member defines a channel which extends along at least a portion of its length. In a separate step, a reinforcing insert or other such support member is provided. This support member is disposed in the channel of the intermediate structural member and affixed thereto so that it is retained in said channel. In a subsequent step, a second forming operation is carried out on the intermediate structural member having the support member retained therein. The second forming operation at least partially encloses and fixedly retains the support member within the channel. In particular instances, at least one of the first and second forming operations are a roll-forming operation.  
      In particular instances, the step of affixing the support member to the intermediate structural member comprises a mechanical affixation step which may employ tabs, toggles, piercings, deformations and the like so as to secure the support member. In other instances, the support member may be adhered by adhesives, or by welding or brazing.  
      In some instances, all or part of the structural component may be subjected to a further processing step, and this processing step may take place before or after the second forming operation. Such further processing steps may include sweeping, bending, die forming, welding, cutting, crushing, heating and/or quenching.  
      The method of the present invention is compatible with continuous, roll-forming processing, and in some instances, an additional cutting step may be implemented either before or after the first or second forming operation.  
      Also disclosed herein are articles made according to the process of the present invention. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIGS. 1A-1E  are schematic illustrations of sequential steps in the method of the present invention;  
       FIG. 2  is a schematic, cross-sectional illustration of a support member being adhesively affixed to an intermediate structural member;  
       FIG. 3  is a schematic, cross-sectional depiction of a support member which is affixed to an intermediate structural member by means of tabs;  
       FIG. 4  is a schematic, cross-sectional view of a support member which establishes an interference fit that affixes it to an intermediate structural member;  
       FIG. 5  shows a structural component of the present invention which has been subjected to a sweep-forming operation;  
       FIGS. 6A and 6B  depict two stages in the formation of a structural member of the present invention in which the intermediate structural member only partially encloses the support member;  
       FIGS. 7A and 7B  depict another embodiment of a structural component of the present invention before and after undergoing the second forming operation; and  
       FIGS. 8A and 8B  depict another embodiment of structural component of the present invention before and after undergoing the second forming operation. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION  
      The present invention is directed to a method for manufacturing a reinforced structural component, such as a pillar, frame or other structural member for a motor vehicle, a building structure, or the like. While the present invention will have utility in the fabrication of metallic and nonmetallic components, it will find particular advantage in fabrication of structural components which include metallic portions. In particular, the present invention is readily adapted for use in high speed metal forming operations such as roll forming.  
      The present invention will be explained with reference to  FIGS. 1A-1E  which are schematic depictions of a general process according to the present invention. The process starts, as is shown in  FIG. 1A , with a body of a sheet material  10 . The sheet material  10  may comprise a ferrous or nonferrous metal, or it may comprise a body of another deformable material such as a polymeric material. As illustrated in  FIG. 1 , the body of sheet material  10  is shown as being a discrete body of material; however, it is to be understood that in many instances, the sheet material may be provided as an elongated web of material such as a body of coiled steel stock or the like. In some instances, the material will be cut into discrete sheets before subsequent forming, while in other instances, forming operations may be carried out, on a continuous basis, on the elongated web of material.  
      In any instance, the body of sheet material  10  is subjected to a first forming operation which alters at least the cross-sectional profile of the body of material  10  so as to form an intermediate structural member  12  as is shown in  FIG. 1B . The intermediate structural member  12  is configured so as to define a channel  14  which extends along at least a portion of the length of the intermediate structural member  12 . In the illustrated embodiment, the channel  14  is defined by two turned-up sidewalls  16 ,  18 , although it is to be understood that other profiles may be utilized in various embodiments of the present invention. As detailed above, a roll-forming process may be employed to form the intermediate structural member  12 . However, other forming operations such as stamping, bending, and the like may also be used in the practice of the present invention.  
      As is shown in  FIG. 1C , a support member  20  is provided. This member  20  serves as a reinforcement in the completed structural component of the present invention. The support member  20  is shown in  FIG. 1C  as having what is generally referred to in the art as a “hat” configuration; but, support members having other configurations, including closed profiles, may be utilized in the practice of the present invention. The support member  20  may be comprised of a body of a ferrous or nonferrous metal, but in other instances the support member may comprise a body of polymeric material, including foamed or foamable polymeric material, or it may comprise a composite of organic and inorganic materials. In some particular instances, the support member may be a metallic member formed by a high-speed forming process such as roll forming. Accordingly, it will be appreciated that a wide variety of support members may be employed in the practice of the present invention.  
      In a subsequent step of the present invention, as is shown in  FIG. 1D , the support member  20  is disposed within the channel  14  of the intermediate structural member  12 , and occupies substantially all of the length of the channel  14 . However, in other embodiments of the present invention, the support member  20  may occupy only a portion of the length of the channel  14 ; and in yet other embodiments, a plurality of support members may be disposed in the channel. In any instance, the support member  20  is affixed to the intermediate structural member  12  so as to be at least temporarily retained therein during subsequent processing. Such affixation may be by mechanical means, adhesive, welding, brazing or the like.  
      Referring now to  FIG. 2 , there is shown a cross-sectional view of an intermediate structural member  12  together with a support member  20  which is in the process of being disposed in the channel  14  thereof. As will be seen from  FIG. 2 , a first body of adhesive  22  and a second body of adhesive  24  are disposed on the flange portions of the support member  20 , and these adhesive bodies  22 ,  24  will at least temporarily affix the support member  20  to the intermediate structural member  12 . Such adhesives may comprise contact adhesives, hot melt adhesives, curable adhesives or the like.  
      Referring now to  FIG. 3 , there is shown a cross-sectional depiction of another embodiment of intermediate structural member  12  which has a support member  20  retained therein by means of tabs  26 ,  28  formed in the sidewalls of the intermediate structural member  12 . These tabs  26 ,  28  project inwardly into the channel  14  and allow the support member  20  to be snapped into place. Yet other configurations may be employed to mechanically affix the support member to the intermediate structural member. For example, as is shown in  FIG. 4 , a support member  20  includes flange portions  30 ,  32  which engage the sidewalls  16 ,  18  of the intermediate structural member  12  and slightly deform so as to provide an interference fit which retains the support member  20  in the channel  14 . In yet other instances, other mechanical affixations such as toggles, piercings, and the like, as well as welds or brazed joints, may be utilized to affix the support member in the channel of the intermediate structural member. It should be noted that any such affixation need only have temporary integrity, since subsequent processing will fixedly join the members. Therefore, short term adhesive bonds or relatively simple mechanical joints may be employed.  
      Referring now back to  FIG. 1E , there is shown a further step in the process of the present invention. Specifically,  FIG. 1E  shows a completed reinforced structural component  40  which is resultant from carrying out a second forming operation on the structure of  FIG. 1D , namely the intermediate structural member  12  having the support member  20  affixed thereto. In the  FIG. 1E  illustration, portions of the sidewalls  16 ,  18  of the intermediate structural member  12  have been folded over so as to define a closed structure which fixedly retains the support member  20  therein. In the illustrated embodiment, the two edges of the sidewalls  16  and  18  join to form a seam  42 ; this seam may be closed in a subsequent operation, such as by welding, although this step is optional. In yet other embodiments, the intermediate structural member may be otherwise shaped in the second forming operation, provided that such shaping causes it to fixedly retain the support member therein. This second forming operation may comprise a roll-forming operation, a bending operation, or any other such forming operation.  
      In some instances, the finished component, or members comprising it, may be subjected to further processing. For example, as is shown in  FIG. 5 , the component  40  of  FIG. 1E  is further shaped in a sweeping process so as to provide it with a transverse curvature. In other instances, further processing may involve bending, twisting, crushing portions of the structure, piercing, drilling, welding, cutting or the like. In yet other instances, further processing may involve heat treatments. For example, the thus fabricated structure may be subjected to a heating and die forming process. Likewise, the component may be subjected to a heat treatment process such as the process of heating and quenching. In other instances, the intermediate structural member may be subjected to such further processing before it is shaped in the second forming operation, and such processing may take place either before or after the support member is affixed. As will be appreciated by those of skill in the art, various processes may be utilized in conjunction with one another.  
      Other modifications and variations of the general process presented herein will be readily apparent to those of skill in the art. While  FIG. 1E  shows the structural component  40  resultant from the second forming step as having a completely closed profile, other such profiles including partially closed profiles may be likewise employed.  FIG. 6A  and  FIG. 6B  show the cross section of yet another structural component made in accord with the principles of the present invention. As is shown in  FIG. 6A , a support member  42  is disposed in an intermediate structural member  12  generally similar to that of  FIG. 1B . The support member  42  has a relatively tall profile which extends across a major portion of the height of the channel  14 .  FIG. 6B  shows the assembly of  FIG. 6A  following the implementation of the second forming operation, which operation involves turning down portions of the sidewalls  16 ,  18  of the intermediate structural member  12 . As is shown in  FIG. 6B , these sidewall portions  16 ,  18  are turned down so as to allow a portion of the support member  42  to project therebetween. As such, the support member is only partially enclosed within the channel  14 , but it cannot be removed without cutting or deforming and hence it is fixedly retained.  
      While the support member has been shown as having a relatively simple hat profile, it is to be understood that numerous other embodiments of support member may be utilized in the practice of the present invention. Such support members may comprise metallic as well as nonmetallic components, and as noted above, in some instances, may comprise foamed or foamable polymeric bodies as well as composite materials. Also, the support members may have cross sections which vary along their length, or are otherwise irregular, depending upon particular applications. Also, the intermediate structural member may be variously configured as discussed above. In some instances, the support member may be a body of a self-adhesive polymeric material, such as a foamable or non-foamable adhesive; in such instances the step of disposing the support member in the intermediate structural member and the step of affixing the support member may be carried out simultaneously.  
       FIGS. 7A and 7B  depict yet other embodiments of the present invention. As shown in  FIG. 7A , an intermediate structural member, which in this instance comprises a simple channel structure of the type shown in  FIG. 1B , has a support member disposed in the channel  14  thereof. The support member  50  has a generally triangular-shaped cross section with two flange portions  52 ,  54  at the vertex thereof. As shown in  FIG. 7A , the flange portions  52 ,  54  project above the sidewalls  16 ,  18  of the channel. In the second forming operation, the flanges  52 ,  54  are folded downward so as to contact the sidewalls  16 ,  18  of the intermediate structural member so as to provide the reinforced structural component. In yet other modifications of this embodiment, portions of the sidewalls  16 ,  18  may be mechanically interlocked to the folded-down flanges  52 ,  54 . As in the other embodiments, the joint portions may be closed by one or more welds.  
      Yet other embodiments may be implemented in accord with the present invention. For example,  FIG. 8A  shows an intermediate structural member  60  which defines a V-shaped channel. A support member  62  having a cylindrical cross section is affixed therein, and as is shown in  FIG. 8B , portions of the sidewalls of the V-shaped intermediate structural member  60  are folded inward so as to retain the support member  62  and thereby define a structural component  64 .  
      The present invention may be implemented in yet other configurations and embodiments. The process of the present invention is readily adapted for high speed manufacturing processes, and is particularly adaptable to processes utilizing sheet steel. Structures of the present invention are simple to manufacture, and have very high strength owing to the reinforced structure thereof. Through the use of lightweight hardenable steels, in conjunction with heat treating or other post forming hardening processes, lightweight, high-strength members such as motor vehicle pillar assemblies, bumper bars, intrusion beams, and the like may be readily fabricated. While this invention has been described primarily with reference to components of motor vehicles, it may likewise be employed to fabricate other structures such as buildings, and other articles of manufacture in which structural components having high strength and light weight are desired.  
      The foregoing drawings, discussion and description are illustrative of some specific embodiments of the present invention, but are not meant to be limitations upon the practice thereof. Yet other modifications and variations thereof will be readily apparent to those of skill in the art. It is the following claims, including all equivalents, which define the scope of the invention.