Patent Publication Number: US-10309449-B2

Title: Ball joint assembly and method of making

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     This divisional patent application claims priority to U.S. Utility patent application Ser. No. 12/124,215, filed May 21, 2008, and is incorporated herein by reference. 
    
    
     BACKGROUND OF THE INVENTION 
     Field of the Invention 
     This invention relates to a ball and socket type joint of the type used in vehicular steering and/or suspension applications and, more particularly, toward a ball joint assembly having an plastic bearing insert and snap ring retainer. 
     Related Art 
     Ball joints are typically used in vehicular applications where three dimensional movement of a wheel or other component is required. The ball joint provides an articulated connection needed when a vehicle is turning and the suspension is accommodating movement over rough terrain or subjected to cornering forces. In the normal course of operation, ball joints are subjected to very high stresses. Thus, their components must be manufactured from strong, usually heavy, materials, such as steel. However, the recent emphasis on reducing vehicular weight is driving design criteria toward ball joints with reduced weight through the incorporation of materials such as various engineering plastics. 
     Furthermore, there is a also a need to reduce both the cost and complexity of components used in motor vehicles. The ball joints are no exception. By manufacturing the ball joint assembly from fewer components, assembly operations are more efficient, thus translating into lower costs particularly where the components can be manufactured to a near-net shape using processes such as molding, rather than the use of extensive machining and grinding operations to form the net-shape components. Additionally, fewer components usually enable weight reduction. Therefore, multiple interests are served by reducing the number of components used in a ball joint assembly, as well as by the use of materials and methods of manufacture which achieve the objective described above. 
       FIGS. 15-16  depict typical prior art ball joint assemblies  210  as used in the application of stabilizer linkages  200 . Heretofore, ball joint assemblies  210  have generally been made by first forming a sturdy, metallic housing  215  and inserting therein one or two bearings  220 ,  222  which form a sliding interface between the articulating ball end  225  of a stud  230  and the housing  215 . A metal cover plate  235  and o-ring  245  are mechanically seated over the housing to retain the bearing components and the ball portion of the stud  230  inside the housing  215  and an elastomeric boot  240  is used to seal ball joint assembly  210  from the external environment, including dirt, salt and other known contaminants. Depending upon the number of bearing components, possible spring take-up members, and dust boot features, this assembly may require five or six separate components not including the ball stud. See for example the exploded view of  FIG. 16  where a typical prior art ball joint assembly is shown requiring six separate components, not including the ball stud  230 , as well as two clamps (not shown) used to secure the dust boot  240  to the housing  215  and stud  230 . 
     In addition to the complexity noted with prior art ball joints and their manufacture, prior art ball joints also typically have a limited ability to resist pull-out forces, or forces which tend to cause the ball stud to pull out of the bearing socket. Generally, prior art ball joints of the sizes and types used for automotive vehicles are able to resist pull-out forces in the range of 350-650 lbs. 
     Thus, there is a continuing desire to further reduce the number of components and the complexity and cost of ball joint assemblies as used in vehicular applications for the purposes mentioned, as well as to improve the ability of these joints to resist pull-out forces. 
     SUMMARY OF THE INVENTION 
     The invention includes an improved ball joint assembly having a reduced number of components six not including the ball stud, and assembly steps, particularly by virtue of its incorporation of an integral bearing cover, and an improved ability to resist pull-out forces as compared to prior art ball joints. 
     In one aspect, the invention includes a ball joint assembly with a ball stud having an attachment stud at one end and a ball portion at an opposing end; a generally cylindrical bearing having an upper end, a lower end, a generally cylindrical exterior sidewall, an upper flange located between the upper end and a ring groove formed in the exterior sidewall, a lower flange proximate the lower end and extending outwardly from the exterior sidewall and a socket cavity that opens toward the lower end, the ball portion engaged in and retained within the socket cavity; a housing having an upper end, a lower end and a generally cylindrical bore extending therebetween and defining a sidewall of the housing and a counterbore proximate the lower end forming a bearing shoulder within the sidewall, the bearing housed in the bore with the lower flange located within the counterbore and engaged with the bearing shoulder; and a retainer located in the ring groove. 
     In another aspect, the ball portion is frustospherical. 
     In yet another aspect, the socket cavity is frustospherical. 
     In yet another aspect, the socket cavity has a circumferentially tapered lead-in and the tapered lead-in tapers so as to converge into the socket cavity. The tapered lead-in may have any suitable angle, but will generally range between about 30 and 45°. 
     In yet another aspect, the bearing incorporates a lead-in taper extending from the top end to the exterior surface. 
     In yet another aspect, the bearing is a one-piece bearing. 
     In yet another aspect, the bearing includes an engineering plastic. 
     In yet another aspect, the bearing includes a plurality of slots which extend from the exterior surface to the socket cavity. The slots may be longitudinally extending, radially spaced slots with reference to a longitudinal axis of said bearing, or longitudinally extending, laterally spaced slots with reference to a longitudinal axis of said bearing. 
     In yet another aspect, the ball joint assembly also includes an integral bearing cover at the top end which encloses the socket cavity. The bearing cover may have a relieved portion which is recessed relative to the top end. The relieved portion may also include a plurality of ribs or struts which extend from the top end into the relieved portion. 
     In yet another aspect, the tapered lead-in defines a cavity opening into the socket cavity which is smaller than a maximum diameter of the socket cavity and operative, by virtue of the socket opening, to capture and retain the ball stud within the bearing and the housing and to resist a pull-out force of at least 650 lbs. applied to the stud relative to the bearing and the housing. The cavity opening may be arranged to provide an overlap amount in the range of about 0.070-0.140 inches between the maximum diameter of the socket cavity and a maximum diameter of the cavity opening and be operative, by virtue of the size of socket opening, to resist a pull-out force of at least 1000 lbs. applied to the stud relative to the bearing and the housing, and may further be in the range of between about 1000-1200 lbs. 
     In yet another aspect, the ball joint assembly may also include a generally cylindrical elastomeric boot having a housing end and a stud end, the housing end enclosing the housing and the stud end partially enclosing the attachment stud. 
     In yet another aspect, the invention includes a method of making a ball joint assembly, using the steps of: forming a ball stud having an attachment stud at one end and a ball portion at an opposing end; forming a housing having an upper end, a lower end and a generally cylindrical bore extending therebetween and defining a sidewall of the housing and a counterbore proximate the lower end forming a bearing shoulder within the sidewall; forming a generally cylindrical bearing having an upper end, a lower end, a generally cylindrical exterior sidewalk an upper flange located between the upper end and a ring groove formed in the exterior sidewall, a lower flange proximate the lower end and extending outwardly from the exterior sidewall and a socket cavity that opens toward the lower end; inserting the ball portion of the ball stud into socket cavity of the bearing; inserting the upper end of the bearing into the bore at the lower end of the housing so as to seat the lower flange of the bearing against the bearing surface of the counterbore and expose the top end of the bearing and the ring groove; and installing the retainer over the top flange sufficiently to achieve locking engagement with the ring groove. The method may also include a step of attaching a generally cylindrical elastomeric boot having a housing end and a stud end to said ball joint assembly, the housing end partially enclosing the housing and the stud end partially enclosing the attachment stud. 
     In yet another aspect the step of forming the bearing includes forming a relieved portion in a top end thereof. The step of forming the bearing with a relieved portion may also comprise forming at least one of a strut or a rib in the relieved portion. 
     In yet another aspect, the step of forming the bearing includes forming a socket cavity opening to the bottom end of the bearing with a tapered lead-in to the socket cavity defining a cavity opening, wherein a size of the cavity opening is selected to resist a pull-out load of at least 650 lbs. 
     In yet another aspect, the step of forming the bearing may also comprise forming at least one longitudinally extending slot in a sidewall of the bearing. This may include forming a plurality of longitudinally extending, radially spaced slots in the sidewall of the bearing, as well as a forming a plurality of longitudinally extending, laterally spaced slots in the sidewall of the bearing. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other features and advantages of the present invention will become more readily appreciated when considered in connection with the following detailed description and appended drawings, like elements have been given the same numbers in the several views, and wherein: 
         FIG. 1  is a perspective view of an exemplary application for the subject ball and socket joint assembly; 
         FIG. 2  is a partial cross-sectional view taken generally along lines  2 - 2  in  FIG. 1 ; 
         FIG. 3  is an exploded partial cross-sectional view of the subject ball and socket joint assembly of  FIG. 2 ; 
         FIG. 4  is a top view of the bearing of  FIG. 3 ; 
         FIG. 5  is a cross-sectional view of the bearing of  FIG. 4  taken along Section  5 - 5 ; 
         FIG. 6  is an enlarged cross-sectional view of the housing of  FIG. 3 ; 
         FIG. 7  is a further cross-sectional enlargement of region  7  of  FIG. 6 ; 
         FIG. 8  is an enlarged cross-sectional view of the boot of  FIG. 3 ; 
         FIG. 9  is a partial cross-sectional view of a stabilizer linkage incorporating the ball joint assemblies of the present invention; 
         FIG. 10A-10F  are schematic illustrations of the steps of a method of assembling a ball joint assembly of the present invention; 
         FIG. 11  is a top view of an alternate bearing configuration in accordance with the invention; 
         FIG. 12  is a cross-sectional view of the bearing of  FIG. 11  taken along section  12 - 12 ; 
         FIG. 13  is a cross-sectional view of the bearing of  FIG. 5  taken along section  13 - 13 ; 
         FIG. 14  is a cross-sectional view of the bearing of  FIG. 12  taken along section  14 - 14 ; 
         FIG. 15  depicts typical prior art ball joint assemblies as used in the application of a stabilizer linkage; and 
         FIG. 16  is an exploded partial cross-sectional view of the ball joint assembly of  FIG. 15 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Referring to  FIGS. 1-14  a vehicular steering and suspension assembly and associated components such as typically used in the front wheels of a motor vehicle is generally shown at  12  in  FIG. 1 . Although the front suspension system  12  is shown here comprising a MacPherson strut  14  type suspension system, it will be appreciated by those of skill in the art that the contemplated ball joint assemblies of the invention may find application in different control arm style suspension systems or in other forms and variations with equal effectiveness. For example, the invention may be deployed in steering or suspension linkages, frame member connections, and other articulating features, including all manner of stabilizer bars, tie rods and the like. Further, a ball joint assembly of the present invention may be utilized in all manner of non-vehicular applications which make use of an articulating joint. 
     Continuing with the illustrative application depicted in  FIG. 1 , the suspension system  12  is shown including a steering knuckle  16  and a spindle (not shown) upon which a vehicular wheel assembly (not shown) is mounted, together with appropriate braking and bearing components as are well known to those of skill in the art. A steering arm  18  extends transversely from steering knuckle  16  and is operatively connected to steering link  20 . A stabilizer bar  22  is depicted including an outer attachment end  24 . The stabilizer bar  22 , which is sometimes referred to as an anti-roll bar, is adapted to receive and resist torsional stresses for the purpose of reducing body roll of the vehicle while influencing its cornering characteristics (i.e., over steer and under steer). A stabilizer link, generally indicated at  26 , is connected at each end  24  of the stabilizer bar through a ball joint assembly, generally indicated at  28 . The stabilizer link  26  connects the outer attachment end  24  of the stabilizer bar  22  and a bracket on the MacPherson strut  14 . Of course, in non-MacPherson strut suspension applications, the stabilizer link  26  may be connected to a different feature, such as for example a lower control arm or other member as is well known to those of skill in the art. In non-suspension or non-vehicular applications, ball joint assembly may be operatively attached to all manner of other elements to promote pivotal or rotational movement therebetween, or a combination thereof. 
       FIGS. 2 and 3  provide assembled and exploded cross-sectional views, respectively, of a ball joint assembly  28  of the invention as taken through the upper end of the stabilizer link  26 ; it being understood that the lower end of the stabilizer link  26  may be a mirror-image of its upper end. Ball joint assembly  28  includes a ball stud  30  having an attachment stud  32  at one end and a ball portion  34  at an opposing end. Ball stud  30  may also include a thread form  36  along attachment portion  32  which is used to attach ball joint assembly  28  to other components, including the components of a typical vehicle suspension system as described herein, using a washer  38  and threaded nut  40  (shown in  FIG. 1 ). Threaded nut  40  may be advanced onto the thread form  36  for establishing the requisite forces and stresses through the ball stud  30  to maintain a secure connection to the strut bracket, or in other applications, other associated elements. 
     Ball joint assembly  28  also includes a generally cylindrical bearing  50  which has an upper end  52 , a lower end  54  and a generally cylindrical exterior sidewall  56 . Bearing  50  also has an upper flange  58  which is located between the upper end  52  and a ring groove  59  formed in the exterior sidewall  56 , and a lower flange  60  which is located proximate the lower end  54  and extends outwardly from the exterior sidewall  56 , as well as a socket cavity  62  that opens toward the lower end  54 . As shown in  FIG. 2 , the ball portion  34  of ball stud  30  is engaged in and retained within and by the socket cavity  62  by means of a snap-fit connection whereby ball portion  34  is inserted into socket cavity  62  as described herein. 
     Ball joint assembly  28  also includes a housing  70  which has an upper end  72 , a lower end  74  and generally cylindrical bore  76  extending therebetween and defining a sidewall  78  of the housing. Housing  70  also has an exterior surface  80 , a counterbore  82  located proximate the lower end  74  and forming a bearing shoulder  84  within the sidewall  78 . Further, a clamp groove  86  may be located on the exterior surface  80 . The bearing  50  is housed in the bore  76  with the lower flange  60  located within the counterbore  82  and engaged in pressing contact with the bearing shoulder  84 . 
     Ball joint assembly  28  also includes a retainer  90  located in the ring groove  59  which together with bearing shoulder  84  captures the bearing  50  within housing  70 . Ball joint assembly  28  may also include a generally cylindrical elastomeric boot  110  which has a housing end  112  and a stud end  114 . The housing end  112  partially encloses the lower end  74  of the housing, and the clamp groove  86  when it is used, and is fixed to the exterior surface  80  of the housing  70  by a suitable retainer  120 . Retainer may be any suitable retainer  120 , such as various housing clamping means  120 , including a spring clamp  120 . The stud end  114  partially encloses and is fixed to the attachment stud  32  by a suitable retainer  130 , such as stud clamping means  130 , including a ring clamp  130 . The various elements of ball joint assembly  28  and their interrelationship, materials, manufacture and assembly are described further below. 
     Referring again to  FIGS. 2 and 3 , ball stud is shown generally at  30 , having a ball portion  34  at one end thereof. The ball portion  34  may be partially spherical. The nature and extent of the spherical portion may vary from a substantially full spherical portion in which the spherical ball is interrupted only by the portion of the sphere surface and interior needed to attach the stud, as shown, to a fractional spherical portion (e.g., a hemispherical, frustospherical or other partial spherical portion) depending on the range and types of articulation needed for the ball joint application. Other non-spherical ball forms, such as ellipsoidal ball/socket forms are also possible in accordance with the invention. An attachment portion  32 , in the form of a stud or shank, extends from the ball portion  34  and may include a thread form  36  or other means for attaching ball stud  30  to an anchoring control member which, in this case, is indicated as the bracket extending from the MacPherson strut  14  (see  FIG. 1 ). Ball stud  30  may also include along the attachment portion  32  a collar groove  33  suitable for sealing engagement with dust boot  110 . Collar groove  33  may have any suitable profile, including various arcuate and partially cylindrical profiles. Ball stud  30  may be made from any suitable material, including various metals and metal alloys, such as various steel alloys. 
     As perhaps best shown in  FIGS. 2 and 3 , a bearing or socket  50  engages and, in the embodiment illustrated, partially surrounds the ball portion  34  of the ball stud  30  for providing an articulating interface therewith which allows pivotal movement with regard to the longitudinal axes associated with each of them, as well as relative rotational movement around these axes. Bearing  50  may be made from any suitable bearing material, including various polymer materials, such as various engineering plastics, including engineering thermoplastics (e.g., polyacetal, polyoxymethylene), which may be adapted to receive sufficient elastic deformation for a snap fit so as to be received in a force-fitting assembly operation with the ball portion  34  (see e.g.,  FIGS. 10A-10B ), as described below. Of course, other material compositions may be substituted, depending upon the particular application requirements and availability. Bearing  50  may be formed using any suitable forming method, including various plastic molding methods, such as various injection molding methods, to form a final or near-net shaped bearing  50 . Bearing  50  is preferably a one-piece bearing, but may also be formed as more than one piece in accordance with the invention, such as a longitudinally divided two-piece or multi-piece bearings or the like. Referring also to  FIGS. 4 and 5 , bearing  50  has a partially-spherical internal socket cavity  62 , which in the embodiment illustrated is a frustospherical socket cavity  62 , which opens to a open lower end  54 , such as by tapered lead-in  66 , such as generally frustoconical tapered bore  66 . The tapered lead-in converges inwardly toward the socket cavity  62  to cavity opening  68 . The taper angle (α) of tapered lead-in  66  together with the profile of the stud portion  32  where it joins to ball portion  34  determine the maximum angle through which ball stud  30  and joint  28  may be articulated with respect to bearing  50  and housing,  70 . The taper angle will generally range from about 30 to 45°. 
     The socket cavity  62  is sized and shaped to contact and engage ball portion  34  while allowing it to swivel or pivot and rotate about the ball portion  34  in typical ball and socket fashion. Typically, the generally circular cavity opening (d 2 )  68  to socket cavity  62  provides a restricted cavity opening  68  which requires elastic deformation of the bearing by expansion of the opening  68  sufficient to permit the ball portion  34  to be inserted through the opening and into socket cavity  62 . The ball portion  34  and cavity opening, as well as other portions of bearing  50 , may be sized relative to one another so as to permit elastic deformation of the cavity opening  68  and bearing  50  sufficient to allow insertion of the ball portion  34  into the socket cavity  62  and retention of the ball portion  34  in pressing, bearing engagement with bearing  50  once the ball portion  34  is inserted into the cavity and the elastic deformation which occurs during insertion is at least partially relieved. Once relieved, the restricted cavity opening  68  and the associated overlapping lower portion  69  of the bearing  50  act to retain the ball portion  34  in bearing  50 . The amount of overlap directly effects the pull-out force (F) required to pull ball portion  34  out of bearing  50  once ball joint assembly  28  has been completely assembled. This aspect of bearing  50  generally determines the maximum pull-out force to which ball joint assembly  28  may be exposed without failure of the joint. In the case of ball joint assembly  28 , with suitable selection of the size, amount of overlap, and materials used for ball stud  30 , bearing  50  and housing  70 , a pull out force of greater than 650 lbs. may be achieved. The amount of overlap represented by the difference between the maximum dimension, such as maximum diameter (d 1 ) of socket cavity  62  and the diameter of cavity opening  68  (d 2 ) will preferably be in the range of 0.070-0.140 inches, generally divided equally as 0.035-0.070 inches per side. By controlling overlap within this range using materials of the types described herein for the ball stud  30 , bearing  50  and housing  70 , ball joint assemblies with pull out forces of greater than 1000 lbs and up to about 1200 lbs. have been achieved for ball joint assemblies of the types and sizes typically employed in automotive applications, such as those having a diameters of ball portion  34  in the general range of about 0.5 to 1.5 inches, and more particularly 0.75-1.2 inches typical of many small to medium size joint configurations such as are used for many tie rod, steering linkage and suspension linkage applications, and more particularly 0.70-0.90 inches commonly used for many steering linkage and suspension linkage applications, including the stabilizer bars as described herein. Thus, in accordance with the invention, the manufacture of steering links having at least one ball joint assembly  28  with a pull-out force of greater than 650 lbs. and up to about 1200 are enabled. 
     The opposite or upper end  52  of bearing  50  is provided with an upper flange  58 . Upper end  52  may be open and include an opening for a grease fitting analogous to that shown in  FIGS. 15 and 16 , or closed as shown in  FIGS. 3-5 . When upper end  52  is closed, it serves as a bearing cover, which in the embodiments shown is an integral bearing cover, as shown, for example, in  FIGS. 4, 5, 11 and 12 , which acts to enclose the upper end  52  of bearing  50 , and particularly socket cavity  62 , thereby preventing dirt, moisture, road debris or other contaminants from infiltrating the joint, particularly the bearing surface and interface between the surface of socket cavity  62  and the surface of ball portion  34 . Exclusion or reduction of such contaminants by incorporation of closed upper end  52  as a bearing cover preserves the operational integrity and longevity of ball joint  28  by eliminating or significantly reducing infiltrating by water, dirt and other contaminants, and thereby associated corrosion and other joint wear mechanisms. 
     The upper end  52  of bearing  50  may also include a relieved portion  51  which is recessed with respect to the other portions of upper end  52 . This feature has the effect of reducing the wall thickness at the upper end  52  as compared to the thickness of one which does not include this feature (not shown except in the areas of top end which do not include the relief), thereby reducing the amount of material needed to form bearing  50 , and from another perspective, maintaining a wall thickness in the upper end  52  that is more uniform and consistent with that of the bearing sidewall  56  than would otherwise be the case. The amount of relief may be varied by adjusting the area of upper end  52  which is relieved and the depth of the relief, as well as the contour or profile of sidewall  47 . The incorporation of relieved portion  51  reduces cost by reducing material usage and can be used to maintain an upper wall  46  thickness profile, including a minimum thickness (t 2 ) which is the same or substantially similar to the wall profile of bearing sidewall  56 , including a minimum thickness (t 1 ). The addition of relieved portion  51  aids in molding bearing  50  by reducing the mold cycle time. Making these profiles similar also reduces or eliminates defects such as warping of bearing  50  that may occur during cooling of the part after molding. 
     Referring to  FIGS. 11-12  which illustrate an alternative embodiment of bearing  50 , bearing  50  may optionally incorporate one or more ribs or struts  48  located in relieved portion  51  to strengthen and stiffen the upper end  52  of bearing  50 , particularly upper wall  46  with respect to forces distributed in upper wall  46  when pull-out or tensile forces (i.e., those forces which have a tendency to pull the ball stud  30  and/or bearing  50  out of the housing are applied to these components. Ribs or struts  48  may extend entirely across relieved portion  51  (i.e., as a rib) or from the side wall  47  to the base  49  of relieved portion (i.e., as a strut), or a combination of both. Without the ribs or struts  48 , it is believed that tensile forces of a sufficient magnitude may cause cupping or other undesired flexure of upper wall  46  proximate relieved portion  51 , which in turn can compromise the attachment of the upper flange  58  and retainer  90  to the housing  70 , thereby effectively lowering the force (F) required to pull the upper flange out of the housing, as well as possibly diminishing the performance of the bearing by altering the stress distribution along the bearing surfaces. In an exemplary embodiment, bearing  50  included twelve struts  48  spaced substantially equally around the circumference of relieved portion  51  which protruded radially inwardly from its side wall  46  and upwardly from its base  49 , and which each had an inner end face  55  which tapers inwardly and downwardly toward base  49 . 
     Referring again to  FIGS. 3, 4, 5, 11, 12, 13 and 14 , bearing  50  also incorporates at least one and preferably a plurality of slots  67 . Slots  67  enable molding by permitting bearing side wall  56  to flex sufficiently to facilitate removal of the portion of the mold used to form socket cavity  62 . Slots  67  also enable flexure of exterior sidewall  56  sufficiently to enable insertion and snap-fit of the ball portion  34  into the socket cavity during assembly of the ball joint  28 . Slot or slots  67  also serve as passages for lubricant, such as grease, which in service is forced into the slots  67  as ball joint  28  is articulated, thereby lubricating the surface of ball portion  34  so as to enhance or maintain the ability to articulate the joint, as well as reduce the wear of the bearing surface. Slots  67  may be longitudinally extending, radially spaced slots as shown in  FIGS. 3-5 . Alternately, slots  67  may be one or more longitudinally extending, laterally spaced slots  67 , where slots  67  define a series of parallel planes  71 , as shown in  FIGS. 11, 12 and 14 . This arrangement is particularly well adapted to formation using standard plastic injection molding methods, since the mold inserts used to form slots  67  may all be withdrawn in the same direction and at the same time, and thus may be formed as a unitary insert, as contrasted with the plurality of inserts needed to form the slot  67  configuration illustrated in  FIGS. 4 and 5 . 
     Retainer  90  may be in the form of a snap ring  90 . The outer diameter of cylindrical side wall  56  and upper flange  58  and the inner diameter of snap ring  90  are sized to receive snap ring  90  in sliding engagement, with appropriate interference, over the exterior surface of upper flange  58 , which may also include a lead-in taper  53  to facilitate sliding engagement of the snap ring  90  as it is pushed over upper end  52 , up the lead-in taper  53  and over the exterior surface of flange  58  and into ring groove  59 . Ring groove  59  is formed in side wall  56  continuously and annularly thereabout, adjacent upper flange  58 . The outer diameter of upper flange  58 , the depth and width of ring groove  59  and the inner diameter of snap ring  90  are sized so as to create an interference that permits insertion of snap ring  90  into ring groove  59  as described, as well as establishes minimum pull-out force necessary to extract the assembly of ball stud  30  and bearing  50  from housing  70  once snap ring  90  has been inserted into ring groove  59 . In an exemplary embodiment, the minimum pull out force was greater than 650 lbs., and may be improved to greater than 1000 lbs, and even in certain combinations greater than about 1200 lbs. In an exemplary embodiment, the diameter of upper flange  58  and cylindrical side wall  56  are about 1.000 inches, while the diameter at the entrance of lead-in taper  53  is about 0.940 inches, and the diameter at the root of the ring groove  59  is about 0.940 inches. The inner diameter of snap ring  90  is about 0.885 inches. Bearing  50  also has external lower flange  60  protruding from bearing side wall  56  proximate entrance opening  61  of socket cavity  62 . In an exemplary embodiment, the diameter of lower flange  60  is about 1.097 inches. Bearing  50  and particularly cavity  62 , act as a bearing and bearing surface, respectively, for ball portion  34 , operatively enabling both rotation of ball stud  30  about longitudinal axis  35  as well as pivoting translation of the stud portion  32  within the limits of travel established by frustoconical taper  66  which limits the pivoting translation of ball stud  30  within bearing  50 . 
     Referring also to  FIGS. 3, 6 and 7 , a rigid, cylindrical housing  70  forms a sleeve-like member disposed about the exterior side wall  56  of bearing  50 . The housing  70  in this example is integrally formed at the ends of the elongated cross-bar of the stabilizer link  26 . This aspect may of course change for other ball joint applications. The housing  70  is open at both ends by virtue of longitudinally extending bore and is provided with an internal relief in the form of counterbore  82  formed in bore  76  proximate lower end  74 . In the fully installed, operational, and assembled condition of the ball joint assembly  28  as shown in  FIG. 2 , the counterbore  82  aligns with and is operative to receive upper surface of exterior lower flange  60  in bearing engagement on shoulder  84 . In an exemplary embodiment, housing  70  has an outer diameter of about 1.375 inches, bore  76  has a diameter of about 1.000 inches and counterbore  82  has a diameter of about 1.110 inches. The wall thickness of housing  70  proximate counterbore  82  is operative to house the ball joint for the intended application and resist the pull-out of ball portion  34  of stud  30  when bearing  50  is retained in housing  70  by snap ring  90 , so as to resist a pull-out force (F (see  FIG. 2 )) of at least 650 lbs. as described herein. 
     Housing  70  may also include a clamp groove  86  located on its outer surface  80 . Clamp groove  86  may be located at any suitable location along the outer surface  80  of housing  70 , but will preferably be located on outer surface  80  proximate lower end  74  which includes counterbore  82 . In the embodiment illustrated in  FIG. 6 , clamp groove  86  is located the lower portion of counterbore  82  proximate the seating shoulder  84 . Clamp groove  86  may have any suitable shape, including a rectangular or trapezoidal cross-sectional shape, as well as the generally arcuate shape shown in  FIGS. 6 and 7 . The generally arcuate shape shown in these figures is generally symmetric about a groove axis  87  (see  FIG. 7 ), which in this embodiment is located slightly above seating shoulder  84 . The generally arcuate shape is formed by two converging tapers having a radius of curvature at the point of convergence. 
     This generally arcuate shape is adapted to receive an attaching clamping means  120 , such as spring clamp  120  or a hand clamp (not shown). Attaching clamping means  120  may be operative for permanent or removable attachment of boot  110  to housing  70 . For example, in the case of a spring clamp  120 , the clamp is expanded to a size such that the inner diameters of spring clamp  120  is greater than the outer diameter of housing  70  and boot  110 , such that it may be expanded and slipped over the outer surface of housing  70  and boot  110  until it is located over clamping groove  86 , wherein it is released allowing the attaching ring  60  to partially close to a diameter which is sufficient to apply a clamping force to the boot  110  and outer surface of housing  70  at the location of clamp groove  86 . In addition to various spring clamps, attaching clamping means  120  may also include various permanent or removable band clamps or other types of clamps suitable for applying the clamping forces described above. 
     Attaching clamping means, such as spring clamp  120 , simultaneously retains the accordion-like rubber dust boot  110  to the housing  70 . Proximate the housing end  112  of dust boot  110 , the inner surface of dust boot  110  may also include an upper protrusion  116  which is operative for engagement in clamp groove  86  together with spring clamp  120 . The lower end  114  of the dust boot  110  includes a collar  118  which is operative to seat on the outer surface of the stud portion  32 . Collar  118  may also include a collar protrusion  119  which is operative to sealingly engage a complementary collar groove  33  feature on the stud  30 , such as shown in  FIG. 2 , generally by operation of a collar ring  130  which may include any form of a retaining ring clamp or the like suitable to retain collar  118  in a seated and sealing relationship to stud portion  30  during articulation or rotation of ball stud  30 . Dust boot  110  may also include grooves to assist in locating the clamping members described herein, including upper groove  115  proximate upper protrusion  116  and lower groove  117  proximate collar  118 , including collar protrusion  119 . Thus, as the bearing  50  articulates or rotates relative to the ball stud  30 , dust boot  110  maintains a secure connection at its upper end  112  and lower end  114  so as to prevent the infiltration of debris into the working interfaces between the bearing  50  and ball portion  34 . Dust boot  110  may be made from any suitable elastomeric material, including various natural or synthetic rubber compositions, various silicones and the like. 
       FIGS. 10A-F  depict, in highly illustrative fashion, the method of making ball joint assembly  28  after the manufacture of the respective components.  FIGS. 10A and 10B  illustrate the assembly of bearing  50  over the ball end portion  34  of ball stud  30  by pressing bearing  50  over ball end portion  34  in the direction shown by arrow  140  to elastically expand bearing  50  until ball portion  34  snaps into semi-spherical socket cavity  62 . It will be understood that the motion of these components is relative, and it is a matter of design and assembly choice in the assembly process for these and the other components described herein as to which component is moved with respect to the other to accomplish a particular assembly or subassembly. Thus, bearing  50  retains ball end portion  34  of ball stud  30 . The ball stud  30  and bearing  50  sub-assembly (see  FIG. 10B ) may then be utilized for further assembly of ball joint assembly  28 . 
     As illustrated in  FIG. 10C , the stud  30  and bearing  50  subassembly is inserted into the lower end  74  of housing  70  in the direction shown by arrow  142 . It is preferred that the outer diameter of bearing  50  establishes an interference fit with the diameter of bore  76 , thereby establishing a preloading of the ball portion  34  and the surface of the socket cavity  62 . The amount of interference establishes the preload of the bearing with larger interferences creating a larger preloads which in to require larger forces to articulate or rotate ball stud  30  within bearing  50 . The relative sizes and the amount of interference is a matter of design choice and will depend on the desired operating characteristic of ball joint assembly  28 , materials selected for bearing  50  and ball portion  34  as well as the surface roughness of the bearing surfaces, lubrication and other factors. In an exemplary embodiment, bearing  50  had a nominal diameter of about 1.007 inches and bore had a nominal diameter of about 1.000 inches, for a diametral interference of about 0.007 inches. The bearing preload establishes the torque necessary to overcome the friction of the bearing surfaces and cause articulation of ball stud  30  within socket cavity  62 , and generally is selected to require a torque in the range of about 5-50 inch-pounds and more preferably between about 20-35 inch pounds, to produce articulation of the joint. Bearing  50  is inserted into bore  76  as described until the upper surface of lower flange  60  seats against bearing shoulder  84  in counterbore  82 , as shown in  FIG. 10D . 
     Once the subassembly of ball stud  30  and bearing  50  has been seated in housing  70 , retainer  90  is installed into ring groove  59 , thereby capturing and fixing bearing  50  within housing  70 . This may be performed by using a retainer  90  in the form of an expandable snap ring  90  as described above, where the snap ring  90  is installed by sliding it over the upper end  52  of bearing  50  in the direction shown by arrow  144  and over upper flange  58  to ring groove  59 , as shown in  FIG. 10E . Snap ring  90  is elastically deformed over these features until it reaches ring groove  59  whereupon the elastically deformed snap ring  59  releases its elastic energy thereby snapping into ring groove  59  to capture bearing  50  within housing  70  as shown in  FIG. 10F . 
     A dust boot  110  as described herein may optionally be installed onto and become a part of ball joint assembly  28 , as also shown in  FIG. 10F . Dust boot  110  is assembled by sliding housing end  112  over the stud portion  32  in the direction shown by arrow  146  until it seats onto the exterior surface  80  of housing  70 . If a clamp groove  86  is employed, the dust boot will preferably incorporate upper protrusion  116 , and will be inserted in the manner described until upper protrusion  116  seats into clamp groove  86 . At the same time, collar  118  engages and is seated onto stud portion  32 , such as by collar protrusion  119  engaging a collar groove  33  which has been formed onto stud portion  32 . Once dust boot  110  is seated in the manner described, retainers  120  and  130 , such as spring clamp  120  and retaining ring  130  may be installed to fix the dust boot  110  to housing  70  and stud portion  32 . The retainers may be permanent or removable depending on the requirements of ball joint assembly  28 . 
     The subject ball joint assembly  28  is distinguished from prior art ball joint assemblies through its use of a socket or bearing  50  which does not require a separate closure cover plate opposite the stud  30 . Further retainer  90  positively resists distortion or expansion of the upper end of the bearing socket  50  if the ball stud  30  is pulled away from the housing  70 . It also positively resists push through of the bearing socket  50  in the direction from which it was installed through the action of lower flange  60  if a push-in force is applied to ball stud  28  and bearing  50  relative to housing  70 . The ball joint assembly of the invention also uses fewer parts, six versus eight, than prior art ball joint assemblies, as shown in  FIGS. 15 and 16 . 
     The foregoing invention has been described in accordance with the relevant legal standards, thus the description is exemplary rather than limiting in nature. Variations and modifications to the disclosed embodiment may become apparent to those skilled in the art and fall within the scope of the invention. Accordingly the scope of legal protection afforded this invention can only be determined by studying the following claims.