Abstract:
The present disclosure provides an elastomeric bushing assembly that includes a multi-piece inner component. The inner component is formed from a standard bar pin and an inner tube. The bar pin is inserted into the inner tube to form the multi-piece inner component. By utilizing different sizes of inner tubes, both standard and heavy duty bushing assemblies can be manufactured using a common bar pin.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application No. 61/786,670, filed on Mar. 15, 2013. The entire disclosure of the above application is incorporated herein by reference. 
     
    
     FIELD 
       [0002]    The present disclosure relates to articulating bushing assemblies. More specifically, the present disclosure relates to elastomeric bushing assemblies that incorporate an interchangeable bar pin. 
       BACKGROUND 
       [0003]    This section provides background information related to the present disclosure which is not necessarily prior art. 
         [0004]    Applications for an elastomeric bushing assembly include, but are not limited to, torsion bars, linear torque rods, V-shaped torque rods, leaf springs, independent suspension control arms and other suspension control devices. These and other applications are used on a wide variety of vehicles such as automobiles, trucks, buses, off-highway vehicles, rail cars and other transportation applications. 
         [0005]    Elastomeric bushing assemblies typically include an outer metal, an inner metal and an elastomeric bushing disposed between the outer metal and the inner metal. The outer metal can be a tubular member which is a part of the component that incorporates the elastomeric bushing assemblies or the outer metal can be a separate tubular member that is designed to be assembled to the component that incorporates the elastomeric bushing assembly by being press fit or otherwise attached to the component. 
         [0006]    The inner metal is typically a solid tubular member which is adapted to be secured to the vehicle and/or suspension member of the application which includes the component that incorporates the elastomeric bushing assembly. One example of an inner metal is a bar pin that has a cylindrical center section and a cylindrical end section disposed at both ends of the center section. The cylindrical end sections extend out from the center section of the outer metal and each cylindrical end section defines a groove which is used to secure the elastomeric bushing assembly to the vehicle and/or the suspension member of the application. 
         [0007]    The solid bar pin can be machined from bar stock, it can be cast, it can be forged or it can be manufactured by other methods in the art. If necessary, the formed solid bar pin can be machined at the flat sections and/or the center section to complete the manufacture of the bar pin. 
         [0008]    Typically, bushing assemblies are manufactured in two families, a standard duty bushing assembly and a heavy duty bushing assembly. These two bushing assemblies are similar when it comes to the cylindrical end portion of the bar pin that extends out from each end of a center section that is disposed within the elastomeric member but the diameter of the center section within the elastomeric member and the diameter of the outer metal are larger for the heavy duty bushing assemblies. This dual design concept has the following disadvantages. First, the bar pin extensions and the center section have to be machined as a single piece solid component. Second, each design of the bushing assembly (standard and heavy duty) must have its own unique bar pin which requires the manufacture and stocking of two separate pins rather than one high volume manufactured pin. Third, typically the elastomeric bushing is molded directly to the bar pin and multiple pin diameters can cause difficulties in the assembly lines for the bushing assemblies. Finally, because of the two different sized center sections, each bushing assembly (standard and heavy duty) require a dedicated mold for the elastomeric bushing. 
       SUMMARY 
       [0009]    This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features. 
         [0010]    The present disclosure provides an elastomeric bushing assembly that incorporates an interchangeable inner metal. The interchangeable inner metal can take the form of a two-piece bar pin which includes a standard sized bar pin and a cylindrical tube which adapts the standard sized bar pin to a specific application. By having multiple sized cylinder tubes, multiple applications can utilize the same bar pin. 
         [0011]    Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure. 
     
    
     
       DRAWINGS 
         [0012]    The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure. 
           [0013]      FIG. 1  is an exploded perspective view of elastomeric bushing assemblies incorporating the multi-piece inner metal in accordance with the present disclosure; 
           [0014]      FIG. 2  is a cross-sectional view of one of the elastomeric bushing assembly illustrated in  FIG. 1 ; and, 
           [0015]      FIG. 3  is a cross-sectional view of the other elastomeric bushing illustrated in  FIG. 1 . 
       
    
    
       [0016]    Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings. 
       DETAILED DESCRIPTION 
       [0017]    Example embodiments will now be described more fully with reference to the accompanying drawings. 
         [0018]    Referring to  FIGS. 1-3 , a pair of elastomeric bushing assemblies  10  and  20  in accordance with the present disclosure, are illustrated. Elastomeric bushing assembly  10  comprises a bar pin  12 , an inner tube  14 , an elastomeric member  16  and an outer tube  18 . Elastomeric bushing assembly  20  comprises bar pin  12 , an inner tube  24 , an elastomeric member  26  and an outer tube  28 . 
         [0019]    Bar pin  12  is a cylindrical member having a constant outside diameter over its entire length. At each end of bar pin  12 , a groove  40  is formed which is used to fasten bar pin  12  and thus elastomeric bushing assemblies  10  and  20  to the vehicle. As illustrated, both elastomeric bushing assembly  10  and elastomeric bushing assembly  20  share the common bar pin  12 . Grooves  40  define means for attaching bar pin  12  to the vehicle. 
         [0020]    Inner tube  14  is a cylindrical tube within which bar pin  12  is located. Inner tube  14  has a constant outside diameter over its entire length and a constant inner diameter over its entire length. The inside diameter of inner tube  14  is less than the outside diameter of bar pin  12  such that a press fit exists between inner tube  14  and bar pin  12 . 
         [0021]    Elastomeric member  16  is an elastomer that is disposed between inner tube  14  and outer tube  18 . Elastomeric member  16  can be molded over inner tube  14  and then pressed into outer tube  18 . The outside diameter of elastomeric member  16  after being molded over inner tube  14  is larger than the inside diameter of outer tube  18  such that a predetermined amount of compression is applied to elastomeric member  16  after elastomeric member  16  is pressed into outer tube  18 . Elastomeric member  16  could be molded into outer tube  18  and then inner tube  14  could be pressed into the inside diameter of elastomeric member  16 . In this case, the as molded inside diameter of elastomeric member  16  would be less than the outside diameter of inner tube  14  such that a predetermined amount of compression is applied to elastomeric member  16  after inner tube  14  is pressed into elastomeric member  16 . Elastomeric member  16  can be bonded to one or both of inner tube  14  and outer tube  18 . 
         [0022]    Outer tube  18  is a cylindrical tube which fully encircles elastomeric member  16 . Outer tube  18  has a constant outside diameter and a constant inside diameter in the area immediately over elastomeric member  16 . Each end of outer tube  18  is curled over to define an annular wall  42  which helps to encapsulate elastomeric member  16 . 
         [0023]    Inner tube  24  is a cylindrical tube within which bar pin  12  is located. Inner tube  24  has a constant outside diameter over its entire length and a constant inner diameter over its entire length. The inside diameter of inner tube  24  is less than the outside diameter of bar pin  12  such that a press fit exists between inner tube  24  and bar pin  12 . Thus, inner tube  14  and inner tube  24  may have the same inside diameter. 
         [0024]    Elastomeric member  26  is an elastomer that is disposed between inner tube  24  and outer tube  28 . Elastomeric member  26  can be molded over inner tube  24  and then pressed into outer tube  28 . The outside diameter of elastomeric member  26  after being molded over inner tube  24  is larger than the inside diameter of outer tube  28  such that a predetermined amount of compression is applied to elastomeric member  26  after elastomeric member  26  is pressed into outer tube  28 . Elastomeric member  26  could be molded into outer tube  28  and then inner tube  24  could be pressed into the inside diameter of elastomeric member  26 . In this case, the as molded inside diameter of elastomeric member  26  would be less than the outside diameter of inner tube  24  such that a predetermined amount of compression is applied to elastomeric member  26  after inner tube  24  is pressed into elastomeric member  26 . Elastomeric member  26  can be bonded to one or both of inner tube  24  and outer tube  28 . 
         [0025]    Outer tube  28  is a cylindrical tube which fully encircles elastomeric member  26 . Outer tube  28  has a constant outside diameter and a constant inside diameter in the area immediately over elastomeric member  26 . Each end of outer tube  28  is curled over to define an annular wall  52  which helps to encapsulate elastomeric member  26 . 
         [0026]    The present disclosure allows for multiple families of parts to share a common component such as bar pin  12 . This allows the consolidation of a large number of components into fewer components with higher volumes for each component. This concept also simplifies the design to eliminate much of the machining, allows for shorter mold times with more pieces per heat and eliminates some of the processing issues the current designs have. The elastomeric bushing assemblies of the present disclosure lower the overall cost while keeping the performance of the elastomeric bushing assemblies the same or better than the current designs while maintaining the overall package size of the elastomeric bushing assemblies to allow them to be direct replacements to the current design. 
         [0027]    Inner tube  14  and inner tube  24  may be designed with the same inside diameter but inner tube  24  has a larger outside diameter than inner tube  14  to represent the barrel outside diameters of the one piece fully machined bar pins used to make the current standard and heavy duty bushings. Inner tube  14  and inner tube  24  can each be processed as separate components to make a finished standard duty cartridge  60  and a finished heavy duty cartridge  62 . Standard duty cartridge  60  comprises bar pin  12 , inner tube  14 , elastomeric member  16  and outer tube  18 . Heavy duty cartridge  62  comprises bar pin  12 , inner tube  24 , elastomeric member  26  and outer tube  28 . Bar pin  12 , with a given spacing between grooves  40 , can then be pressed into either standard duty cartridge  60  or heavy duty cartridge  62  to create elastomeric bushing assembly  10  and elastomeric bushing assembly  20 , respectively. 
         [0028]    The design described in the disclosure allows the current design of bar pin  12  to be built from two components, inner tube  14  or inner tube  24  that represents the pin barrel outside diameter and a straight constant outside diameter bar pin  12  sized to the outside diameter of the pin extension or the current design. With this concept, elastomeric member  16  and elastomeric member  26  can be molded directly to inner tube  14  and inner tube  24 , respectively. In the current design, the elastomeric member is molded directly to the fully machined bar pin. This allows inner tube  14  and inner tube  24  to be processed through manufacturing into finished standard duty cartridge  60  and finished heavy duty cartridge  62 , respectively without bar pin  12 . Bar pin  12  can then be pressed into standard duty cartridge  60  or heavy duty cartridge  62 . Inner tube  14  and/or inner tube  24  can be designed with an inside diameter and an outside diameter such that no machining of inner tubes  14 ,  24  is required or inner tube  14  and/or inner tube  24  can be machined. Bar pin  12  can be designed such that as rolled bar stock can be used thus eliminating any machining other than grooves  40  or bar pin  12  can be designed to be machined over its entire length. 
         [0029]    Inner tube  14  and inner tube  24  may be a metal component, a plastic component or any other material which meets the performance requirements for elastomeric bushing assembly  10  and elastomeric bushing assembly  20 , respectfully. 
         [0030]    The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure.