Abstract:
Various embodiments of the invention include products and parts including a frictional damping means and methods of making and using the same.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a continuation-in-part of U.S. patent application Ser. No. 11/780,828, filed Jul. 20, 2007, a continuation-in-part of U.S. patent application Ser. No. 11/475,759, filed Jun. 27, 2006, which claims the benefit of U.S. Provisional Application No. 60/718,945, filed Sep. 20, 2005; and a continuation-in-part of U.S. patent application Ser. No. 10/961,813, filed Oct. 8, 2004; and a continuation-in-part of U.S. patent application Ser. No. 11/475,756, filed Jun. 27, 2006 which claims the benefit of U.S. Provisional Application No. 60/718,579, filed Sep. 19, 2005; a continuation-in-part of U.S. patent application Ser. No. 11/440,916, filed May 25, 2006 which claims the benefit of U.S. Provisional Application No. 60/717,310, filed Sep. 15, 2005; a continuation-in-part of U.S. patent application Ser. No. 11/554,234, filed Oct. 30, 2006. 
     
    
     TECHNICAL FIELD  
       [0002]    The field to which the disclosure generally relates includes products and components thereof including means for damping and methods of making and using the same. 
       BACKGROUND 
       [0003]    Product parts may produce undesirable noise when vibrated, or may vibrate at an undesirable amplitude for an prolonged period when struck or set in motion. 
       SUMMARY OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
       [0004]    Various embodiments of the invention include products and parts including a frictional damping means and methods of making and using the same. 
         [0005]    Other exemplary embodiments of the invention will become apparent from the detailed description provided hereinafter. It should be understood that the detailed description and specific examples, while disclosing exemplary embodiments of the invention, are intended for purposes of illustration only and are not intended to limit the scope of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0006]    Exemplary embodiments of the invention will become more fully understood from the detailed description and the accompanying drawings, wherein: 
           [0007]      FIG. 1  is a sectional view with portions broken away of one embodiment of the invention including an insert. 
           [0008]      FIG. 2  is a sectional view with portions broken away of one embodiment of the invention including two spaced apart frictional surfaces of a cast metal body portion. 
           [0009]      FIG. 3  is a sectional view with portions broken away of one embodiment of the invention including an insert having a layer thereon to provide a frictional surface for damping. 
           [0010]      FIG. 4  is a sectional view with portions broken away of one embodiment of the invention. 
           [0011]      FIG. 5  is an enlarged view of one embodiment of the invention. 
           [0012]      FIG. 6  is a sectional view with portions broken away of one embodiment of the invention. 
           [0013]      FIG. 7  is an enlarged sectional view with portions broken away of one embodiment of the invention. 
           [0014]      FIG. 8  is an enlarged sectional view with portions broken away of one embodiment of the invention. 
           [0015]      FIG. 9  is an enlarged sectional view with portions broken away of one embodiment of the invention. 
           [0016]      FIG. 10  illustrates one embodiment of the invention. 
           [0017]      FIG. 11  is a sectional view with portions broken away of one embodiment of the invention. 
           [0018]      FIG. 12  is a sectional view with portions broken away of one embodiment of the invention. 
           [0019]      FIG. 13  is a plan view with portions broken away illustrating one embodiment of the invention. 
           [0020]      FIG. 14  is a sectional view taken along line  14 - 14  of  FIG. 13  illustrating one embodiment of the invention. 
           [0021]      FIG. 15  is a sectional view with portions broken away illustrating one embodiment of the invention. 
           [0022]      FIG. 16  is a sectional view, with portions broken away illustrating another embodiment of the invention. 
           [0023]      FIG. 17  is a schematic perspective view of an electric drive motor housing including an insert according to one embodiment of the invention. 
           [0024]      FIG. 18  is a schematic perspective view of a transmission housing including an insert according to one embodiment of the invention. 
           [0025]      FIG. 19  is a schematic perspective view of a combustion engine exhaust gas manifold including an insert according to one embodiment of the invention. 
           [0026]      FIG. 19  is a schematic perspective view of a combustion engine cylinder head including an insert according to one embodiment of the invention. 
           [0027]      FIG. 21  is a schematic perspective view of a differential including an insert according to one embodiment of the invention. 
           [0028]      FIG. 22  is a schematic perspective view of a combustion engine block including an insert according to one embodiment of the invention. 
           [0029]      FIG. 23  is a schematic perspective view of a rear end housing including an insert according to one embodiment of the invention. 
           [0030]      FIG. 24  is a sectional view of the head of a golf club according to one embodiment of the invention. 
           [0031]      FIG. 25  is a perspective view of a baseball bat including an insert according to one embodiment of the invention. 
           [0032]      FIG. 26  illustrates an archery bow including stabilizers including an insert. 
           [0033]      FIG. 27  is a sectional view of a shaft including a frictional damping means, an insert as a core and a surrounding metal layer. 
           [0034]      FIG. 28  is a sectional view illustrating a shaft having a metal core and a frictional damping means including an insert surrounding the core. 
           [0035]      FIG. 29  is a sectional view of a bearing including a frictional damping means including an insert surrounded by a metal body. 
           [0036]      FIG. 30  is a sectional view illustrating a bearing including a three lobe insert frictional damping means. 
           [0037]      FIG. 31  is a sectional view of a bearing including a five lobe insert frictional damping means. 
           [0038]      FIG. 32  is a schematic perspective view of a vehicle brake rotor including a frictional damping means according to one embodiment of the invention. 
       
    
    
     DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS 
       [0039]    The following description of the embodiment(s) is merely exemplary in nature and is in no way intended to limit the invention, its application, or uses. 
         [0040]    Referring to  FIGS. 1-16 , one embodiment of the invention includes a product or part  500  having a frictional damping means. The frictional damping means may be used in a variety of applications including, but not limited to, applications where it is desirable to reduce noise associated with a vibrating part or reduce the vibration amplitude and/or duration of a part that is struck, dynamically loaded, excited, or set in motion. In one embodiment the frictional damping means may include an interface boundary conducive to frictionally damping a vibrating part. In one embodiment the damping means may include frictional surfaces  502  constructed and arranged to move relative to each other and in frictional contact, so that vibration of the part is dissipated by frictional damping due to the frictional movement of the surfaces  502  against each other. 
         [0041]    According to various illustrative embodiments of the invention, frictional damping may be achieved by the movement of the frictional surfaces  502  against each other. The movement of frictional surfaces  502  against each other may include the movement of: surfaces of the body  506  of the part against each other; a surface of the body  506  of the part against a surface of the insert  504 ; a surface of the body  506  of the part against the layer  520 ; a surface of the insert  504  against the layer  520 ; a surface of the body  506  of the part against the particles  514  or fibers; a surface of the insert  504  against the particles  514  or fibers; or by frictional movement of the particles  514  or fibers against each other or against remaining binder material. 
         [0042]    In embodiments wherein the frictional surface  502  is provided as a surface of the body  506  or the insert  504  or a layer  520  over one of the same, the frictional surface  502  may have a minimal area over which frictional contact may occur that may extend in a first direction a minimum distance of 0.1 mm and/or may extend in a second (generally traverse) direction a minimum distance of 0.1 mm. In one embodiment the insert  504  may be an annular body and the area of frictional contact on a frictional surface  502  may extend in an annular direction a distance ranging from about 20 mm to about 1000 mm and in a transverse direction ranging from about 10 mm to about 75 mm. The frictional surface  502  may be provided in a variety of embodiments, for example, as illustrated in  FIGS. 1-16 . 
         [0043]    Referring again to  FIG. 1 , in another embodiment of the invention one or more of the outer surfaces  522 ,  524  of the insert  504  or surfaces  526 ,  528  of the body  506  of the part  500  may include a relatively rough surface including a plurality of peaks  510  and valleys  512  to enhance the frictional damping of the part. In one embodiment, the surface of the insert  504  or the body  506  may be abraded by sandblasting, glass bead blasting, water jet blasting, chemical etching, machining or the like. 
         [0044]    As shown in  FIG. 2 , in one embodiment one frictional surface  502  (for example extending from points A-B) may be a first surface of the body  506  of the part  500  positioned adjacent to a second frictional surface  502  (for example extending from points C-D) of the body  506 . The body  506  may include a relatively narrow slot-like feature  508  formed therein so that at least two of the frictional surfaces  502  defining the slot-like feature  508  may engage each other for frictional movement during vibration of the part to provide frictional damping of the part  500 . In various embodiments of the invention, the slot-like feature  508  may be formed by machining the cast part, or by using a sacrificial casting insert that may be removed after the casting by, for example, etching or machining. In one embodiment a sacrificial insert may be used that can withstand the temperature of the molten metal during casting but is more easily machined than the cast metal. Each frictional surface  502  may have a plurality of peaks  510  and a plurality of valleys  512 . The depth as indicated by line V of the valleys  512  may vary with embodiments. In various embodiments, the average of the depth V of the valleys  512  may range from about 1 μm-300 μm, 50 μm-260 μm, 100 μm-160 μm or variations of these ranges. However, for all cases there is local contact between the opposing frictional surfaces  502  during component operation for frictional damping to occur. 
         [0045]    In another embodiment of the invention the damping means or frictional surface  502  may be provided by particles  514  or fibers provided on at least one face of the insert  504  or a surface of the body  506  of the part  500 . The particles  514  may have an irregular shape (e.g., not smooth) to enhance frictional damping, as illustrated in  FIG. 10 . One embodiment of the invention may include a layer  520  including the particles  514  or fibers which may be bonded to each other or to a surface of the body  506  of the part or a surface of the insert  504  due to the inherent bonding properties of the particles  514  or fibers. For example, the bonding properties of the particles  514  or fibers may be such that the particles  514  or fibers may bind to each other or to the surfaces of the body  506  or the insert  504  under compression. In another embodiment of the invention, the particles  514  or the fibers may be treated to provide a coating thereon or to provide functional groups attached thereto to bind the particles together or attach the particles to at least one of a surface of the body  506  or a surface of the insert  504 . In another embodiment of the invention, the particles  514  or fibers may be embedded in at least one of the body  506  of the part or the insert  504  to provide the frictional surface  502  ( FIGS. 5-6 ). 
         [0046]    In embodiments wherein at least a potion of the part  500  is manufactured such that the insert  504  and/or the particles  514  or fibers are exposed to the temperature of a molten material such as in casting, the insert  504  and/or particles  514  or fibers may be made from materials capable of resisting flow or resisting significant erosion during the manufacturing. For example, the insert  504  and/or the particles  514  or fibers may include refractory materials capable of resisting flow or that do not significantly erode at temperatures above 1100° F., above 2400° F., or above 2700° F. When molten material, such as metal, is cast around the insert  504  and/or the particles  514 , the insert  504  or the particles  514  should not be wet by the molten material so that the molten material does not bond to the insert  504  or layer  520  at locations wherein a frictional surface  502  for providing frictional damping is desired. 
         [0047]    Illustrative examples of suitable particles  514  or fibers include, but are not limited to, particles or fibers including silica, alumina, graphite with clay, silicon carbide, silicon nitride, cordierite (magnesium-iron-aluminum silicate), mullite (aluminum silicate), zirconia (zirconium oxide), phyllosilicates, or other high-temperature-resistant particles. In one embodiment of the invention the particles  514  may have a length along the longest dimension thereof ranging from about 1 μm-350 μm, or 10 μm-250 μm. 
         [0048]    In embodiments wherein the part  500  is made using a process wherein the insert  504  and/or the particles  514  or fibers are not subjected to relatively high temperatures associated with molten materials, the insert  504  and/or particles  514  or fibers may be made from a variety of other materials including, but not limited to, non-refractory polymeric materials, ceramics, composites, wood or other materials suitable for frictional damping. For example, such non-refractory materials may also be used (in additional to or as a substitute for refractory materials) when two portions of the body  506  of the part  500  are held together mechanically by a locking mechanism, or by fasteners, or by adhesives, or by welding  518 , as illustrated in  FIG. 4 . 
         [0049]    In another embodiment of the invention, the layer  520  may be a coating over the body  506  of the part or the insert  504 . The coating may include a plurality of particles  514  which may be bonded to each other and/or to the surface of the body  506  of the part or the insert  504  by an inorganic or organic binder  516  ( FIGS. 3-4 ,  9 ) or other bonding materials. Illustrative examples of suitable binders include, but are not limited to, epoxy resins, phosphoric acid binding agents, calcium aluminates, sodium silicates, wood flour, or clays. In another embodiment of the invention the particles  514  may be held together and/or adhered to the body  506  or the insert  504  by an inorganic binder. In one embodiment, the coating may be deposited on the insert  504  or body  506  as a liquid dispersed mixture of alumina-silicate-based, organically bonded refractory mix. 
         [0050]    In another embodiment, the coating may include at least one of alumina or silica particles, mixed with a lignosulfonate binder, cristobalite (SiO 2 ), quartz, or calcium lignosulfonate. The calcium lignosulfonate may serve as a binder. In one embodiment, the coating may include IronKote. In one embodiment, a liquid coating may be deposited on a portion of the insert and may include high temperature Ladle Kote 310B. In another embodiment, the coating may include at least one of clay, Al 2 O 3 , SiO 2 , a graphite and clay mixture, silicon carbide, silicon nitride, cordierite (magnesium-iron-aluminum silicate), mullite (aluminum silicate), zirconia (zirconium oxide), or phyllosilicates. In one embodiment, the coating may comprise a fiber such as ceramic or mineral fibers. 
         [0051]    When the layer  520  including particles  514  or fibers is provided over the insert  504  or the body  506  of the part the thickness L ( FIG. 3 ) of the layer  520 , particles  514  and/or fibers may vary. In various embodiments, the thickness L of the layer  520 , particles  514  and/or fibers may range from about 1 μm-400 μm, 10 μm-400 μm, 30 μm-300 μm, 30 μm-40 μm, 40 μm-100 μm, 100 μm-120 μm, 120 μm-200 μm, 200 μm-300 μm, 200 μm-250 μm, or variations of these ranges. 
         [0052]    In yet another embodiment of the invention the particles  514  or fibers may be temporarily held together and/or to the surface of the insert  504  by a fully or partially sacrificial coating. The sacrificial coating may be consumed by molten metal or burnt off when metal is cast around or over the insert  504 . The particles  514  or fibers are left behind trapped between the body  506  of the cast part and the insert  504  to provide a layer  520  consisting of the particles  514  or fibers or consisting essentially of the particles  514  or fibers. 
         [0053]    The layer  520  may be provided over the entire insert  504  or only over a portion thereof. In one embodiment of the invention the insert  504  may include a tab  534  ( FIG. 3 ). For example, the insert  504  may include an annular body portion and a tab  534  extending radially inward or outward therefrom. In one embodiment of the invention at least one wettable surface  536  of the tab  534  does not include a layer  520  including particles  514  or fibers, or a wettable material such as graphite is provided over the tab  534 , so that the cast metal is bonded to the wettable surface  536  to attach the insert  504  to the body  506  of the part  500  but still allow for frictional damping over the remaining insert surface which is not bonded to the casting. 
         [0054]    In one embodiment of the invention at least a portion of the insert  504  is treated or the properties of the insert  504  are such that molten metal will not wet or bond to that portion of the insert  504  upon solidification of the molten metal. According to one embodiment of the invention at least one of the body  506  of the part or the insert  504  includes a metal, for example, but not limited to, aluminum, steel, stainless steel, cast iron, any of a variety of other alloys, or metal matrix composite including abrasive particles. In one embodiment of the invention the insert  504  may include a material such as a metal having a higher melting point than the melting point of the molten material being cast around a portion thereof. 
         [0055]    In one embodiment the insert  504  may have a minimum average thickness of 0.2 mm and/or a minimum width of 0.1 mm and/or a minimum length of 0.1 mm. In another embodiment the insert  504  may have a minimum average thickness of 0.2 mm and/or a minimum width of 2 mm and/or a minimum length of 5 mm. In other embodiments the insert  504  may have a thickness ranging from about 0.1-20 mm, 0.1-6.0 mm, or 1.0-2.5 mm, or ranges therebetween. 
         [0056]    Referring now to  FIGS. 7-8 , again the frictional surface  502  may have a plurality of peaks  510  and a plurality of valleys  512 . The depth as indicated by line V of the valleys  512  may vary with embodiments. In various embodiments, the average of the depth V of the valleys  512  may range from about 1 μm-300  82  m, 50 μm-260 μm, 100 μm-160  82  m or variations of these ranges. However, for all cases there is local contact between the body  506  and the insert  504  during component operation for frictional damping to occur. 
         [0057]    In other embodiments of the invention improvements in the frictional damping may be achieved by adjusting the thickness (L, as shown in  FIG. 3 ) of the layer  520 , or by adjusting the relative position of opposed frictional surfaces  502  or the average depth of the valleys  512  (for example, as illustrated in  FIG. 2 ). 
         [0058]    In one embodiment the insert  504  is not pre-loaded or under pre-tension or held in place by tension. In one embodiment the insert  504  is not a spring. Another embodiment of the invention includes a process of casting a material comprising a metal around an insert  504  with the proviso that the frictional surface  502  portion of the insert used to provide frictional damping is not captured and enclosed by a sand core that is placed in the casting mold. In various embodiments the insert  504  or the layer  520  includes at least one frictional surface  502  or two opposite friction surfaces  502  that are completely enclosed by the body  506  of the part. In another embodiment the layer  520  including the particles  514  or fibers that may be completely enclosed by the body  506  of the part or completely enclosed by the body  506  and the insert  504 , and wherein at least one of the body  506  or the insert  504  comprises a metal or consists essentially of a metal. In one embodiment of the invention the layer  520  and/or insert  504  does not include or is not carbon paper or cloth. 
         [0059]    Referring again to  FIGS. 1-4 , in various embodiments of the invention the insert  504  may include a first face  522  and an opposite second face  524  and the body  506  of the part may include a first inner face  526  adjacent the first face  522  of the insert  504  constructed to be complementary thereto, for example nominally parallel thereto. The body  506  of the part includes a second inner face  528  adjacent to the second face  524  of the insert  504  constructed to be complementary thereto, for example parallel thereto. The body  506  may include a first outer face  530  overlying the first face  522  of the insert  504  constructed to be complementary thereto, for example parallel thereto. The body  506  may include a first outer face  532  overlying the second face  524  of the insert  504  constructed to be complementary thereto, for example parallel thereto. However, in other embodiments of the invention the outer faces  530 ,  532  of the body  506  are not complementary to associated faces  522 ,  524  of the insert  504 . When the damping means is provided by a narrow slot-like feature  508  formed in the body  506  of the part  500 , the slot-like feature  508  may be defined in part by a first inner face  526  and a second inner face  528  which may be constructed to be complementary to each other, for example parallel to each other. In other embodiments the surfaces  526  and  528 ;  526  and  522 ; or  528  and  524  are mating surfaces but not parallel to each other. 
         [0060]    Referring to  FIGS. 11-12 , in one embodiment of the invention the insert  504  may be an inlay wherein a first face  522  thereof is not enclosed by the body  506  of the part. The insert  504  may include a tang or tab  534  which may be bent downward as shown in  FIG. 11 . In one embodiment of the invention a wettable surface  536  may be provided that does not include a layer  520  including particles  514  or fibers, or a wettable material such as graphite is provided over the tab  534 , so that the cast metal is bonded to the wettable surface  536  to attach the insert  504  to the body of the part but still allow for frictional damping on the non-bonded surfaces. A layer  520  including particles  514  or fibers may underlie the portion of the second face  524  of the insert  504  not used to make the bent tab  534 . 
         [0061]    In another embodiment the insert  504  includes a tab  534  which may be formed by machining a portion of the first face  522  of the insert  504  ( FIG. 12 ). The tab  534  may include a wettable surface  536  having cast metal bonded thereto to attach the insert  504  to the body of the part but still allow for friction damping by way of the non-bonded surfaces. A layer  520  including particles  514  or fibers may underlie the entire second face  524  or a portion thereof. In other embodiments of the invention all surfaces including the tabs  534  may be non-wettable, for example by way of a coating  520  thereon, and features of the body portion  506  such as, but not limited to, a shoulder  537  may be used to hold the insert  504  in place. 
         [0062]    Referring now to  FIG. 13 , one embodiment of the invention may include a part  500  having a body portion  506  and an insert  504  enclosed by the body part  506 . The insert  504  may include through holes formed therein so that a stake or post  540  extends into or through the insert  504 . 
         [0063]    Referring to  FIG. 14 , which is a sectional view of  FIG. 13  taken along line  14 - 14 , in one embodiment of the invention a layer  520  including a plurality of particles  514  or fibers (not shown) may be provided over at least a portion of the insert  504  to provide a frictional surface  502  and to prevent bonding thereto by cast metal. The insert  504  including the layer  520  may be placed in a casting mold and molten metal may be poured into the casting mold and solidified to form the post  540  extending through the insert  504 . An inner surface  542  defining the through hole of the insert  504  may be free of the layer  520  or may include a wettable material thereon so that the post  540  is bonded to the insert  504 . Alternatively, in another embodiment the post  504  may not be bonded the insert  504  at the inner surface  542 . The insert  504  may include a feature such as, but not limited to, a shoulder  505  and/or the post  540  may include a feature such as, but not limited to, a shoulder  537  to hold the insert in place. 
         [0064]    Referring now to  FIG. 15 , in another embodiment, the insert may be provided as an inlay in a casting including a body portion  506  and may include a post  540  extending into or through the insert  504 . The insert  504  may be bonded to the post  540  to hold the insert in place and still allow for frictional damping. In one embodiment of the invention the insert  504  may include a recess defined by an inner surface  542  of the insert  504  and a post  540  may extend into the insert  504  but not extend through the insert  504 . In one embodiment the post  504  may not be bonded to the insert  504  at the inner surface  542 . The insert  504  may include a feature such as, but not limited to, a shoulder  505  and/or the post  540  may include a feature such as, but not limited to, a shoulder  537  to hold the insert in place. 
         [0065]    Referring now to  FIG. 16 , in another embodiment of the invention, an insert  504  or substrate may be provided over an outer surface  530  of the body portion  506 . A layer  520  may or may not be provided between the insert  504  and the outer surface  530 . The insert  504  may be constructed and arranged with through holes formed therethrough or a recess therein so that cast metal may extend into or through the insert  504  to form a post  540  to hold the insert in position and still allow for frictional damping. The post  540  may or may not be bonded to the insert  504  as desired. The post  540  may extend through the insert  504  and join another portion of the body  506  if desired. 
         [0066]    The frictional damping means as described herein may be used in a variety of applications, for example, in automotive parts such as brake rotors, brackets, pulleys, brake drums, transmission housings, gears, engines and engine components and other parts may undergo unwanted or undesirable vibrations, and may even produce noise that is transmitted into the passenger compartment of a vehicle. The frictional damping means may also be used to address undesirable vibrations in parts or components including, but not limited to, sporting equipment, housing appliances, manufacturing equipment such as lathes, mill/grinding/drilling machines, earth moving equipment, and other non-automotive applications, and components that are subject to dynamic loads and vibration.  FIG. 17-32  are illustrative examples of such applications. 
         [0067]    Referring now to  FIG. 17 , one embodiment of the invention includes a product which may include an electric drive motor housing including a body portion  506  formed from a cast metal. An insert  504  may be included in the housing as an inlay, or completely enclosed in a wall of the housing. The insert  504  may include tabs  534  as desired. The body portion  506  may be bonded to the tabs  534  as described above. 
         [0068]    Referring now to  FIG. 18 , one embodiment of the invention may include a product  500  which may be a transmission housing including inserts  504  which may be completely enclosed by a wall of the transmission housing or may be provided as an inlay in the wall of the transmission housing according to various embodiments of the invention. 
         [0069]    Referring now to  FIG. 19 , one embodiment of the invention may include a product  500  which may be a combustion exhaust gas manifold including inserts  504  which may be completely enclosed or may be provided as an inlay in a wall forming the combustion engine exhaust gas manifold. 
         [0070]    Referring now to  FIG. 20 , one embodiment of the invention may include a product  500  which may be a combustion engine cylinder head including inserts  504  which may be completely enclosed or provided as an inlay in a wall of the cylinder head. 
         [0071]    Referring now to  FIG. 21 , one embodiment of the invention may include a product  500  which may be a differential case including inserts  504  which may be completely enclosed or provided as an inlay in a wall of the differential case. 
         [0072]    Referring now to  FIG. 22 , one embodiment of the invention may include a product  500  which may be an engine block including inserts  504  which may be completely enclosed or provided as an inlay in a wall of the engine block. 
         [0073]    Referring now to  FIG. 23 , one embodiment of the invention may include a product  500  which may be a rear end housing for a rear wheel drive vehicle including at least one insert  504  which may be completely enclosed or may be provided as an inlay in a wall of the rear end housing. 
         [0074]    Referring now to  FIG. 24 , one embodiment of the invention may include a product  500  which may include a head of a golf club iron which may include an insert  504  therein for providing frictional damping according to one embodiment of the invention. The golf club may include a shaft attached to the head and the insert  504  may be provided in the shaft in addition to or alternatively to providing the insert  504  in the head of the golf club. The insert  504  may provide a frictional damping means to reduce vibration of the head and/or the shaft when the club strikes a golf ball or the ground. 
         [0075]    Referring now to  FIG. 25 , one embodiment of the invention may include a product  500  which may be in the form of a metal baseball bat including an insert  504  as a frictional damping means. The frictional damping means may reduce the vibration of the baseball bat upon striking an object such as a baseball. 
         [0076]    Referring now to  FIG. 26 , one embodiment of the invention may include a stabilizer(s)  600  for an archery bow  602  which may comprise a metal and may include a frictional damping means such as an insert  504  in the body portion  506  of the stabilizer  600  to reduce the vibration of the bow and/or the bow string (not shown) which may occur when shooting an arrow with the bow. 
         [0077]    Referring now to  FIG. 27 , one embodiment of the invention may include a shaft  500  including a frictional damping means which may include an insert  504  as a central core and concentric metal layer as a body portion  506 . The insert  504  and the body portion  506  may be keyed to each other so that they rotate together. 
         [0078]    Referring now to  FIG. 28 , one embodiment of the invention may include a shaft  500  having a central metal core as a body portion  506  and a frictional damping means which may include a concentric insert  504  surrounding the body portion  506 . The insert  504  and the body portion  506  may be keyed to each other so that they rotate together. 
         [0079]    Referring now to  FIG. 29 , one embodiment of the invention may include a bearing  500  including a frictional damping means which may include a cylindrical insert  504  surrounded by an inner and outer concentric body portion  506  which may be made of a metal. The bearing  500  may have a bore  604  extending therethrough to receive a shaft therein. A shaft rotating in the bearing  500  may have a destructive resonance frequency which could result in damage to the part in which the bearing  500  is located. The insert  504  provides a frictional damping means to dissipate undesirable vibration or osculation of the shaft. 
         [0080]    Referring now to  FIG. 30 , another embodiment of the invention may include a bearing  500  including a frictional damping means which may include three lobe inserts  504  which may be positioned at 60 degrees with respect to each other or at an equal distance from each other. The inserts  504  may serve to reduce the vibration or osculation of a shaft spinning in the bore  604  of the bearing. Similarly, as illustrated in  FIG. 31 , another embodiment may include a bearing  500  having five lobe inserts  504  equally spaced from each other. 
         [0081]    Referring now to  FIG. 32 , one embodiment of the invention may include a vehicle brake rotor  500  which may include a body portion  506  which may be a brake rotor cheek  606  having a first flat face  608  and an opposite flat face  610  for engagement with a brake pad. The brake rotor includes a frictional damping means which may include an insert  504  received in the brake cheek  606 . The vehicle brake rotor  500  may include a hub portion  612  attached to the cheek  606 . The hub portion  612  may include a central aperture  614  and a plurality of bolt holes  616  for attaching the brake rotor to a vehicle drive system. 
         [0082]    Another embodiment of the invention includes a machine such as a stamping machine, band saw, drill or the like which includes a wall comprising a metal which is vibrated during operation of the machine, and wherein the wall includes a friction damping means including but not limited to an insert, as described above. 
         [0083]    When the term “over,” “overlying,” “overlies,” “under,” “underlying,” or “underlies” is used herein to describe the relative position of a first layer or component with respect to a second layer or component such shall mean the first layer or component is directly on and in direct contact with the second layer or component or that additional layers or components may be interposed between the first layer or component and the second layer or component. 
         [0084]    The above description of embodiments of the invention is merely exemplary in nature and, thus, variations thereof are not to be regarded as a departure from the spirit and scope of the invention.