FIELD OF THE INVENTION 
   The present invention relates generally to ball and socket joints and more particularly to a ball and socket joint sealing bellows and a ball and socket joint assembly with a bellows or sealing boot to ball stud (ball pin) connection and to a sealing boot. 
   BACKGROUND OF THE INVENTION 
   Ball and socket joins are known that have a sealing boot connected at one end to a housing of the ball joint and connected at another end to a ball stud (ball pin) and/or a knuckle (the connected piece or mating part—connected to the ball pin). The end of the sealing boot is either directly applied to the ball stud or knuckle or is applied by the use of a sealing ring. 
   Sealing rings are known that apply pressure to a bellows to urge it into engaging with the ball pin or knuckle or to form an engagement surface to facilitate the sealing of the sealing boot relative to the ball pin or knuckle. Such sealing rings are difficult to form and use radial press fit to define a sealing surface. The parts must be handled very carefully to avoid damage or handling marks. After the parts are pressed on they cannot adjust with regard to axial length if the knuckle has to be changed. An axial seal to the knuckle is not present. 
   SUMMARY OF THE INVENTION 
   It is an object of the invention to provide an easy assembly of a sealing boot (bellows seal) to ball and socket joint parts that presents a good seal, particularly in an axial direction of the sealing boot, knuckle (connected part) and stud (pin) interface. 
   According to the invention a ball and socket joint bellows seal is provided with a ball pivot pin with a connection piece, a bellows with an annular engagement surface with a sliding ring groove and a bellows seal element. The bellows seal element has a connection piece sealing face statically engaged with said connection piece, a radially extending sealing portion and a sliding ring portion connected to said radially extending sealing portion and extending into the sliding ring groove. 
   The radially extending sealing portion may provide a static engagement with the connection piece. With this an axial seal is provided and the sliding ring portion slides in the ring groove. The radially extending sealing portion may be fixed to the connection piece. 
   The sliding ring groove may have a widened portion spaced axially inwardly of the substantially radially extending engagement surface. The sliding ring portion may have a widened portion spaced axially inwardly of the radially extending sealing portion. 
   Lubricant may be disposed in the sliding ring groove. The substantially radially extending engagement surface may have a lubricant retaining portion defined by one of a narrowed gap and a material barrier at an entrance of the sliding ring groove. The lubricant retaining portion then acts to retain at least a portion of the lubricant in the sliding ring groove in a pre-assembly state prior to the sliding ring portion being inserted into the widened portion of the sliding ring groove and to form a seal in a state with the sliding ring portion inserted into the widened portion of the sliding ring groove with an amount of lubricant at each of two sealing sides of the widened portion. The annular engaging surface may extend substantially in a radial direction with respect to the connection piece. 
   The bellows seal element may have a pivot pin sealing surface engaged with the pivot pin. A clamping ring acting on an outside of the bellows may be provided to apply force to the bellows such that the pivot pin sealing surface statically engages with the pivot pin. 
   According to another aspect of the invention, a process is provided for forming a ball and socket joint. The process includes providing a ball pivot pin seated in a ball joint housing and providing a connection part with a radially extending surface having an opening for receiving the ball pivot pin. A bellows is provided with a first connection end with an annular housing connection surface and another end with an annular engagement surface having a sliding ring groove. The bellows is connected to the housing. A bellows seal element is with a connection piece sealing face, a radially extending sealing portion and a sliding ring portion connected to the radially extending sealing portion. The radially extending sealing portion of the bellows seal element is connected to the connection part radially extending surface. The ball pivot pin is moved into the opening of the connection part. The sliding ring portion is inserted into the sliding ring groove. 
   According to still another aspect of the invention, a sealing boot is provided comprising a bellows with an annular engagement surface with a sliding ring groove and a bellows seal element with a connection piece sealing face to statically engage with a joint connection part, a radially extending sealing portion and a sliding ring portion connected to the radially extending sealing portion and extending into the sliding ring groove. 
   The sliding ring groove may have a widened portion spaced axially inwardly of the substantially radially extending engagement surface. A lubricant may be disposed in the sliding ring groove. 
   The slipping ring may have plural slipping ring portions, arranged concentrically and coaxial to engage in corresponding concentric and coaxial grooves of the bellows element. 
   The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated. 


   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is an exploded view of the boot seal and slipping ring assembly according to the invention; 
       FIG. 2  is an exploded sectional view showing a detail of the assembly of  FIG. 1 ; 
       FIG. 3  is a sectional view showing the structure of  FIG. 2A  in an assembled state; 
       FIG. 4  is a partial sectional view of a ball joint ball and pin seated in a housing connected to a bellows (sealing boot); 
       FIG. 5  is a sectional view showing a connection piece (knuckle) with a slipping ring attached to an upper surface thereof; 
       FIG. 6A  is a sectional view of a knuckle facing side of the sealing boot with lubricant in a guiding groove; 
       FIG. 6B  is a sectional view of an alternative embodiment of the sealing boot, with the flaps or a membrane limiting the entrance to the guiding groove having lubricant therein; 
       FIG. 7A  is a sectional view showing a state of assembly with the sealing boot contacting the slipping ring; 
       FIG. 7B  is a sectional view showing another state of assembly as the ball pin advances with respect to the connection piece; 
       FIG. 7C  is a sectional view showing the assembled state; 
       FIG. 8A  is an enlarged sectional view showing the sealing boot and sliding ring in a pre-assembly state, relatively positioned for engagement; 
       FIG. 8B  is an enlarged sectional view showing the sealing boot and sliding ring in an assembled state; 
       FIG. 8C  is an enlarged sectional view showing the sealing boot and sliding ring in an assembled state illustrating the axial seal (sealing in an axial direction to prevent water ingress in a radial direction); 
       FIG. 9A  is an enlarged sectional view showing a state of the sealing boot and the sliding ring assembly process with an embodiment not using a clamping ring; 
       FIG. 9B  is an enlarged sectional view showing another state of the sealing boot and sliding ring assembly process; 
       FIG. 9C  is an enlarged broken away sectional view showing the assembled state of sealing boot and sliding ring with pin and knuckle according to the embodiment of  FIG. 9A ; 
   


   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Referring to the drawings in particular, the invention comprises a bellows seal arrangement or boot seal arrangement generally designated  10 . The boot seal arrangement  10  includes a boot seal  12  and a snap in slipping ring or bellows seal element  14 . The boot seal  12  has a housing end  15  and a connection piece end  18 . The connection piece end  18  has an annular surface  16  with an annular guiding groove  20 . The slipping ring  14  has a connection piece engagement portion with surface  22  and opposite boot seal engaging surface  26 . The slipping ring  14  also has a sliding ring portion  28 . 
     FIG. 2  shows the sealing ring  14  with boot sealing engaging surface  26  in a position ready to be seated in contact with sealing boot surface  16 . The sliding ring portion  30  snaps into the guiding groove  20  with widened portion  32  passing through a narrow entranceway  64  into widened portion  23  of guiding groove  20 .  FIG. 3  shows the sliding ring portion  30  snapped into the dining groove  20 . 
   The boot seal arrangement  10  is advantageously used with a ball and socket joint including ball  36  with pin  38  as shown in  FIG. 4 . The ball  36  is seated in a housing  44  (via intermediate bearing insert). The pin  38  is connected to a connecting piece or knuckle  40 . The sealing boot  12  is connected at end  15  to the housing  44  via a clamping ring  46 . The end  18  of sealing boot  12  is connected to the pin  38  by a clamping ring  48 . The clamping ring  48  may be omitted as discussed further below. 
     FIG. 5  shows the knuckle  40  with a sealing boot facing surface  42 . The slipping ring surface  22  is positioned on the surface  42  to form a seal between the slipping ring surface  22  and knuckle  40  based on a soft gripping material coating (e.g. rubber) at the surface  22  or by the use of a sticky material such or an adhesive (e.g. contact glue). 
   The guiding groove  20  may be provided with a lubricant  66  as shown in FIG.  6 A. This may be supplied in a preassembled state with the lubricant  66  already in position. The guide groove  20  may have an advantageous ratio of the width d of the opening  64  to the width D of the widened portion  23 . With a sufficiently small dimension d, the lubricant may be substantially retained in the space  23 , even during shipping and handling. Further, a film may be applied over the gap  64  during shipping and handling. Further, according to an alternative embodiment according to  FIG. 6B , flaps  70  or a film or membrane thickness of material  70  is integrally formed with the sealing boot  12 . In this case the lubricant  66  is injected through the membrane  70  or passes through a gap in the flaps  70 . 
     FIG. 7A-7C  show the assembly process in which a tapered surface of the pin  38  is seated in contact with the tapered surface of the knuckle  40 . In  FIG. 7A  the surface  16  is positioned over the surface  26  and the gap  64  is aligned with the ring  30  (see also  FIG. 8A ). The ring  30  snaps into guiding groove  20  and the pin or stud  38  is advanced as shown in  FIG. 7B . With the movement of the stud  38  into a seated position in three opening of the knuckle  40  the sealing boot  12  applies force toward the knuckle  40 . Some amount of lubricant  66  may exit the space  23  for reducing friction for relative slip between sealing boot  12  and slipping ring  14  and for improving sealing characteristics. As shown in  FIG. 8C , a good seal is provided based on the water ingress path  55  passing through to oil barriers  66 . 
     FIG. 9A-9C  show the assembly process in which a tapered surface of the pin  38  is seated in contact with the tapered surface of the knuckle  40  for an alternate embodiment. In the embodiment of  FIGS. 9A-C  no clamping ring is used at sealing boot end  18 . Instead, the snap in connection between the sealing boot  12  and the slipping ring  14  as well as the geometry of the arrangement is such that the ring  30  grasps the sealing boot  12  and applies a radial force sufficient to replace the clamping ring. The length of the ring  30  may be a bit longer to provide a varied degree of radial pressure. The shape of the widened portion  32  may be varied for different properties such as maintaining more lubricant in the region of widened portion  32 , in order to apply more radial pressure or to provide different fit aspects (snap fit). In  FIG. 9A  the surface  16  is positioned over the surface  26  and the gap  64  is aligned with the ring  30 . The ring  30  snaps into guiding groove  20  and the stud  38  is advanced as shown in  FIG. 9B . With the movement of the stud  38  into a seated position in the opening of the knuckle  40  the sealing boot  12  applies force toward the knuckle  40 . Some amount of lubricant  66  will exit the space  23 , reducing friction for relative slip between sealing boot  12  and slipping ring  14  and improving sealing characteristics. The water ingress path is again through two oil barriers  66 .  FIG. 9C  shows the assembled position with the pin  38  bearing on the engagement surface  24 , the bellows  12  applying force from an upper direction toward the surface  26  and the ring  30  cooperating to retain the bellows end  18  in the assembled position. 
   While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles.
A ball and socket joint bellows seal is provided with a ball pivot pin with a connection piece, a bellows with an annular engagement surface with a sliding ring groove and a bellows seal element. The bellows seal element has a connection piece sealing face statically engaged with said connection piece, a radially extending sealing portion and a sliding ring portion connected to said radially extending sealing portion and extending into the sliding ring groove.