Abstract:
A light weight alloy part is molded in a mold containing at least one weldable metal insert, so that portions of portions of the alloy part lap portions of the insert to securely lock the weldable insert to the light weight alloy part. The resulting hybrid part is thus both light weight and weldable to other assemblies and sub-assemblies.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. patent application Ser. No. 12/840,486 filed Jul. 21, 2010 which claims priority from U.S. Provisional Patent Application Ser. No. 61/229,838, filed Jul. 30, 2009. 
     
    
     BACKGROUND OF THE INVENTION 
       [0002]    1. Technical Field 
         [0003]    The present invention relates to the manufacture of light weight parts for assembly with other parts. Such parts are frequently used in airplanes and vehicles. 
         [0004]    2. Background Art 
         [0005]    British Patent 686,428 issued in 1954 discloses riveting strips of steel sheet metal to elongated aluminum-magnesium alloy profiled bearers. Steel sheet metal is welded to the strips of steel sheet metal. 
         [0006]    Mellis et al., U.S. Patent Application Publication No. 2007/0271793, published Nov. 29, 2007 discloses a suspension arm for use in a vehicle, in which a coupling for assembling the arm to other components of the vehicle is attached to a tubular member made of steel, aluminum or the like, using a cast-in-place technique, rather than conventional welding. 
       SUMMARY OF THE INVENTION 
       [0007]    In the present invention, a light weight alloy part is molded in a mold containing at least one weldable metal insert, so that portions of portions of the alloy part lap portions of the insert to securely lock said weldable insert to the light weight alloy part. The resulting hybrid part is thus both light weight and weldable to other assemblies and sub-assemblies. 
         [0008]    These and other objects, advantages and features of the invention will be more fully understood and appreciated by reference to the written specification and drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]      FIG. 1  is a perspective and relatively close-up view of a known steering column support bracket, with the bracket being stamped and MIG-welded to the tubular member of an instrument panel frame; 
           [0010]      FIG. 2  is a perspective view of an embodiment of a hybrid assembly consisting of a steel instrument panel frame and steering column support bracket comprising a magnesium-casted part and a steel insert assembly; 
           [0011]      FIG. 3  is a perspective view of the steering column support bracket illustrated in  FIG. 2 ; 
           [0012]      FIG. 4  is a perspective view of the steering column support bracket shown in  FIG. 2 , and illustrating the location of the holes or forms within the steel stampings positioned below the magnesium line; 
           [0013]      FIG. 5  is a perspective view showing the separate components of the steel inserts of the steel stampings of the steering column support bracket; and 
           [0014]      FIG. 6  is a perspective and stand-alone view of the magnesium-casted component of the steering column support bracket. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0015]    The principles of a preferred embodiment are disclosed, by way of example, in a vehicle part  200  as described herein and illustrated in  FIGS. 2-6 . The vehicle part  200  includes components comprised of steel and of magnesium, with the use of magnesium facilitating a relative reduction in weight. The structure of the vehicle part  200  and preferred processes for manufacturing the vehicle part  200  permit the use of welding processes, although magnesium components are known to be essentially unweldable to other parts. 
         [0016]      FIG. 1  illustrates a known vehicle part  100 . The known vehicle part  100  can be characterized as an instrument panel reinforcement frame with a steering column support bracket. More specifically, the vehicle part  100  includes an instrument panel reinforcement frame or main frame  102  having a configuration as shown in part in  FIG. 1 . A greater portion of the main frame  102  is illustrated in  FIG. 2  as frame  202 , which incorporates the preferred embodiment and will be described in subsequent paragraphs herein. The main frame  102  includes a tubular member  104  which extends across the entirety of the upper portion of the main frame  102 . 
         [0017]    Secured to the tubular member  104  of the main frame  102  is a steering column support bracket  106 . The known steering column support bracket  106  includes an upper or top plate  108  having a substantially rectangular configuration as illustrated in  FIG. 1 . Extending downwardly from opposing sides of the upper plate  108  are a pair of downwardly extending flanges  110 . The downwardly extending flanges  110  can be integral with or otherwise secured to a pair of webs  112 . In turn, the webs  112 , at their edges opposing the edges adjacent the downwardly extending flanges  110 , are coupled to or are integral with a pair of wings  114 . For purposes of mating the steering column support bracket  106  to the tubular member  104 , the downwardly extending flanges  110  each include an arcuate cut  116  having a shape conforming to the curvature of the outer surface of the tubular member  104 . In addition, each of the wings  114  also includes an edge having an arcuate cut  118 . Again, the arcuate cuts  118  are shaped to as to conform to the curvature of the tubular member  104 . With the arcuate cuts  116 ,  118 , the elements of the steering column support bracket  106  securely mate with the tubular member  104  of the main frame  102 .  FIG. 1  also illustrates a pair of bolts  122  which can be used to secure the steering column support bracket  106  to other components of the steering column itself. 
         [0018]    For purposes of securing the steering support bracket  106  to the tubular member  104 , the support bracket  106  can be directly welded to the tubular member  104 , through MIG welding and resistance welding processes. Weld lines for the support bracket  106  and the tubular member  104  are shown as lines  120  in  FIG. 1 . 
         [0019]    As previously described, the known vehicle part  100  includes the steering bracket support column  106  which is comprised of steel or steel alloys, and which are of relatively substantial weight. To reduce the weight and still permit the use of welding processes to secure a support bracket to a main frame in the manufacture of the vehicle part, the preferred embodiment  200  illustrated in  FIGS. 2-6  provides for a relatively lighter weight steering column support bracket, while still permitting the use of welding processes in the manufacture of the entirety of the vehicle part. 
         [0020]    The preferred embodiment comprised of the vehicle part  200  is specifically shown in  FIGS. 2-6 . As apparent from subsequent description, a number of the components of the vehicle part  200  correspond to the components of the vehicle part  100  with respect to the main frame. In fact, one of the advantages of the preferred embodiment is the addition of a relatively lighter weight magnesium part into the assembly of the steering column support bracket and main frame, without substantial modification to the assembly process. That is, the steering column support bracket in accordance with the preferred embodiment will still be MIG welded to components of the main frame. 
         [0021]    More specifically, and with respect to  FIGS. 2-6 , the vehicle part  200  includes a main frame  202 , shown substantially in its entirety in  FIG. 2 . The main frame  202 , in this particular embodiment, is shown as an instrument panel reinforcement frame. However, it should be emphasized that numerous parts can be manufactured in accordance with processes associated with the preferred embodiment, other than the specific main frame and steering column support bracket described herein. 
         [0022]    The main frame  202  includes a tubular member  204  extending substantially along the entirety of the length of the main frame  202 . Secured to the tubular member  204  of the main frame  202 , through welding processes, is a steering column support bracket  206 . The steering column support bracket  206 , when assembled with the main frame  202 , performs the same functions as the steering column support bracket  106  previously described with respect to the vehicle part  100 . However, unlike the steering column support bracket  106 , the steering column support bracket  206  of the preferred embodiment comprises a magnesium part  208  which is molded to weldable steel inserts  210 . The magnesium part  208  is shown in a perspective and stand-alone configuration in  FIG. 6 . In accordance with the preferred embodiment, the magnesium part  208  is of a relatively lighter weight than steel components, and is the principle part of the assembly, the weldable steel inserts being smaller. Yet, the weldable steel inserts are sufficiently large as to space the magnesium part  208  sufficiently far from the welder to avoid igniting the magnesium during the welding process. 
         [0023]    In addition to the magnesium part  208 , the steering column support bracket  206  also includes steel inserts  210 . The steel inserts  210  are also shown in a perspective and stand-alone configuration in  FIG. 5 . As illustrated therein, the steel inserts  210  can include three inserts. The inserts are shown as center insert  212  and a pair of opposing side inserts  214 . 
         [0024]    With respect to the center insert  212 , and as shown particularly in  FIGS. 3 ,  4  and  5 , the insert  212  includes a substantially rectangular top plate  216 . A pair of extending flanges  218  extend downwardly from the top plate on opposing sides thereof. The downwardly extending flanges  218  each include an arcuate cut  220  having a shape and configuration as primarily shown in  FIG. 5 . The shape and configuration of the arcuate cut  220  will conform to the curvature of the tubular member  204  for purposes of mating the components together. 
         [0025]    Turning to the side inserts  214 , each side insert  214  is comprised of an outwardly extending steel wing  222 . The steel wings  222  are shown in detail primarily in  FIG. 5 . Each of the outwardly extending steel wings  222  includes a downwardly extending flange  224 . Each downwardly extending flange  224  includes an arcuate cut  226 . The arcuate cuts  226 , as with the arcuate cuts  220 , are also shaped so as to conform to the curvature of the tubular member  204 . In addition, and as will be apparent from subsequent description herein, the shape and configuration of the downwardly extending flanges  218  and  224  will conform to shapes and configurations of elements of the magnesium part  208  described subsequently herein. 
         [0026]    Reference is now made to  FIGS. 4 and 5 , showing the elements of the steel inserts  210 . As shown therein, the center insert  212  and side inserts  214  all include a series of holes  228  positioned at various locations on the inserts  210 . More specifically, and primarily with reference to  FIG. 5 , three holes  228  are shown within the top plate  216 . A pair of holes  228  are shown in a top portion of each of the outwardly extending steel wings  222 . Further, holes  228  are positioned through the downwardly extended flanges  218  of the center insert  212 , and the downwardly extending flanges  224  of the side inserts  214 . In manufacture of the vehicle part  200 , the holes  15  will allow molten magnesium to flow from one side of a steel insert  210  to the other side thereof. When the magnesium hardens, the hardening action will serve to lock the steel inserts  210  in place, with respect to the magnesium part  208 . Without this locking function, the magnesium, in view of its properties, would not bond to the steel of the steel inserts  210  to any significant degree. 
         [0027]    Reference is now made primarily to  FIG. 6 , showing a stand-alone configuration of the magnesium part  208 . The magnesium part  208  includes, in this particular embodiment, a center portion  230  and a series of plates  232  at various angled configurations relative to one another. Positioned outwardly relative to the center portion  230  are a pair of extending members  234 , which extend from a front to a rear of the steering column support bracket  206 . Each of the extending members  234  includes an inner and downwardly extending flange  236  which can be integral with the sides of the plates  232 . At the bottom of the inner downwardly extending flanges  236  is a lower section  238  which can be positioned substantially at a right angle with respect to the corresponding flange  236 . Positioned on the lower sections  238  are a set of strengthening ribs  240  which extend from the front to the rear of the magnesium part  208 . A series of webs  242 , again for strengthening purposes, are positioned transversely across the ribs  240 . Extending upwardly from the lower sections  238  are a pair of outer flanges  244 . The magnesium part  208  can also include a set of formed bushings  246 , for purposes of receiving connecting components for securing the steering column support bracket  206  to other components of the steering column. 
         [0028]      FIG. 3  illustrates a stand-alone, perspective view of the entirety of the steering column support bracket  206 , specifically showing the magnesium part  208  and the steel inserts  210 . The steel inserts  210  can be formed through conventional stamping processes. The magnesium part  208  can be formed as a casting through injection molding processes. During the molding processes, the steel inserts  210 , appropriately positioned with respect to the magnesium part molding configuration, are insert molded and over-molded. 
         [0029]    To appropriately secure the steel inserts  210  to the magnesium part  208 , the previously described holes  228  are positioned relative to the mold for the magnesium part  208 , so that the holes  228  in the top plate  216  and in the upper portions of the outwardly extending steel wings  222  are located below the center portion  230  and the outwardly extending wings  248  of the magnesium part  208 . When in these positions, and also with respect to the holes  228  located in the flanges  218  and  224  of the steel inserts  210 , the holes  228  will permit molten magnesium injected into the mold to flow from one side of each of the steel inserts  210  to the other side. When the molten magnesium hardens, the resultant steering column support bracket  206  will have the configuration as particularly shown in  FIGS. 3 and 4 . As apparent from the relative positioning of the steel inserts  10  and the magnesium part  208  as shown in these drawings, the steel inserts  210  are essentially locked in place relative to the magnesium part  208 . This function permits the steel inserts  214  to be coupled to the magnesium part  208 , without any use of welding or other connecting processes which are difficult to achieve with magnesium and similar metals. 
         [0030]    In addition to the advantageous functions of the holes  228 , another aspect of the preferred embodiment for the vertical part  200  is the use of a series of beads  250 . The beads  250  are particularly shown in  FIGS. 3 and 5  and are located on the steel inserts  210 . More specifically, the beads  250  can be characterized as being located at each position where there is a junction between a portion of the magnesium part  208  and a portion of the steel inserts  210  of the support bracket  206 . When the steel inserts  210  are positioned in the injection mold, and the molten magnesium is injected into the mold, the beads  250  serve to substantially prevent any molten magnesium from covering surfaces of the steel inserts which need to be exposed for purposes of facilitating welding of the steel inserts to the tubular member  204 . 
         [0031]    Certain other aspects of the preferred embodiment and other embodiments can also be described. With respect to the holes  228 , it should be noted that the holes  228  can take other shapes and configurations within the steel inserts  210 . Of primary importance is that the holes or other formations in the steel inserts are positioned below what could be characterized as the “magnesium line” so as to allow the magnesium to flow through the holes or other formations during the molding stage, for purposes of effectively locking the steel inserts  210  to the magnesium part  208 . 
         [0032]    With the steel inserts  210  forming part of the steering column support bracket  206 , the support bracket  206  can still be welded to the tubular member  204  or other components of the main frame  202 . That is, although the preferred embodiment advantageously utilizes a magnesium part  208  for the support bracket  206 , the use of the steel inserts  210  still provide the capability of welding (such as by MIG welding or resistance welding) the bracket  206  to the main frame  202 . Accordingly, the general process of assembling the steering column support bracket  206  to the main frame  202  is not substantially changed in that the bracket  206  is still welded to the tubular member  204 . 
         [0033]    It is also possible to achieve the advantages of the embodiment, while having a differing relative configuration of the steel inserts  210  and the magnesium part  208 . For example, at least part of the steel inserts  210  could be positioned in other locations relative to the magnesium part  208  and the entirety of the support bracket  206 . That is, at least part of the steel inserts  210  could be positioned in the middle of the entirety of the support bracket  206 , with openings positioned within the magnesium part  208 . Such a configuration would allow for the capability of more extensive welding positions. 
         [0034]    The steel utilized for the steel inserts  210  can be one of a number of variations. For example, it is believed that any 1008-1020 hot rolled, cold rolled or plate steel may be utilized for the steel inserts  210 . It may also be possible to utilize aluminum. However, a potential difficulty with the use of aluminum is that distortion must be avoided. 
         [0035]    Also, it should be emphasized that the preferred embodiment described herein is directed specifically to a main frame  202  and steering column support bracket  206 . It is clear from the foregoing description that the advantageous processes associated with the preferred embodiment may be used for various types of structural components, in vehicles and for other purposes. 
         [0036]    It will be apparent to those skilled in the pertinent arts that other embodiments of hybrid parts and processes associated with manufacture thereof can be designed. That is, the principles of hybrid parts and processes for manufacture are not limited to the specific embodiment described herein. Accordingly, it will be apparent to those skilled in the art that modifications and other variations of the above-described illustrative embodiment may be effected without departing from the spirit and scope of the novel concepts of the embodiment.