Abstract:
A sealing bellows is provided having a jacket ( 1   b ) arranged between first and second edges ( 1   a   , 1   c ) of the sealing bellows. The edges ( 1   a   , 1   c ) of the sealing bellows are sealingly in contact with components in the assembled state of the sealing bellows ( 1 ). At least a first edge ( 1   a ) of the sealing bellows has radially inwardly pointing teeth ( 3   a ), which engage a contour of a component or a housing ( 2 ) of a ball and socket joint to form a snap connection.

Description:
FIELD OF THE INVENTION 
   The present invention pertains to a sealing bellows for ball and socket joints, especially for motor vehicles, the sealing bellows having a jacket arranged between a first edge and a second edge of the sealing bellows, wherein the edges of the sealing bellows are sealingly in contact with components in the assembled state of the sealing bellows. 
   BACKGROUND OF THE INVENTION 
   Packings or sealing systems, also called rubber bellows, are frequently used in the area of chassis engineering. They are located, e.g., in the area of ball and socket joints or drive axles. The packings or rubber bellows have the function of a seal, which separate the inner functional area of, e.g., a ball and socket joint, from outside effects during both rotary movements and tilting movements. As a result, additional wear, e.g., in the form of friction and corrosion, is avoided. The edges of the bellows are usually provided with additional straining rings, which apply pressure to the mostly metallic components, e.g., the housing of a ball and socket joint or a pivot, so that the sealing bellows is secured against slipping off in the axial direction. These sealing bellows or packings usually also have additional collars projecting inwardly in the radial direction, which extend behind projections on the components and thus ensure an additional axial fixation in addition to the straining ring. Such sealing bellows of this class for ball and socket joints are known from DE-OS 1 575 708, DE-OS 1 168 717 as well as DE-PS 925 328. 
   The drawback of the sealing bellows or packings of this kind is that an additional straining ring is always needed for the secure axial fixation of the sealing bellows, so that not only are additional parts needed, but the assembly effort is also relatively high as a result. 
   SUMMARY OF THE INVENTION 
   The object of the present invention is to provide a sealing bellows that avoids the above-described drawbacks. 
   According to the invention, a sealing bellows is provided with a jacket arranged between a first edge and a second edge of the sealing bellows. The edges of the sealing bellows are sealingly in contact with components in the assembled state of the sealing bellows. A first edge of the sealing bellows has radially inwardly pointing teeth. The present invention also comprises the use of the sealing bellows according to the present invention for ball and socket joints. 
   The sealing bellows according to the present invention has the advantage that no straining ring is needed for the sealing and durable fastening of the bellows to a component. The sealing bellows can be advantageously pushed easily over a component with its teeth, the teeth being bent over due to their shape and pivoting into corresponding recesses of the component. The teeth advantageously have the shape of sawteeth, so that the teeth can be bent over in one direction only. As a result, the sealing bellows can slip off from the component unintentionally only if a force that may possibly destroy the bellows is applied. 
   The teeth may be made in one piece with the sealing bellows. However, it is also possible for the teeth to be injection molded in one piece with the sealing bellows, e.g., by means of a two-component technique. It is also possible for the sealing ring carrying the teeth to be injection molded with or bonded to the sealing bellows. 
   By providing a plurality of circular rows of teeth, a very good sealing is achieved between the sealing bellows and the component. Due to the absence of the straining ring in the area of the teeth, a dynamic connection is obtained, which is advantageously designed as a snap connection. It can be guaranteed by the advantageous embodiment of the component that the edge of the sealing bellows, which carries the teeth, can no longer move in the axial direction, i.e., in the direction of the pivot. 
   It is obviously possible for each edge of the sealing bellows to have corresponding teeth, so that a straining ring is no longer needed for both sides. However, it is, of course, also possible for an edge of the sealing bellows to be secured statically against unintentional separation by means of a straining ring. Thus, this edge of the sealing bellows may have sealing lips, which come sealingly into contact with the component due to the action of the force of the straining ring. The edge of the sealing bellows advantageously has an outwardly pointing, circular groove for receiving the sealing ring for this purpose, so that the sealing ring cannot unintentionally slip off the sealing bellows after the assembly. 
   All plastics may be generally considered for use as the material for the teeth or the snap hook connection. However, thermoplastics, which possess good tribological and elastic properties, are preferred. 
   Possible embodiments of sealing bellows according to the present invention and ball and socket joints according to the present invention will be explained in greater detail below on the basis of drawings. 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 a cross-sectional view of a ball and socket joint protected by means of a sealing bellows according to the present invention; 
       FIG. 2  is an enlarged detail of  FIG. 1 ; 
       FIG. 3  is a cross-sectional view of another possible embodiment with an optional straining ring; 
       FIG. 4  is a cross-sectional view of another possible embodiment with an additional tooth element, which is arranged on a component, e.g., a ball and socket joint housing; and 
       FIG. 5  is another possible embodiment with a ring made of metal or plastic, which is incorporated by vulcanization or is extrusion coated. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Referring to the drawings in particular,  FIGS. 1 and 2  show the detail of a ball and socket joint, comprising a housing  2 , which accommodates a socket, not shown. A ball pivot  4  with its joint ball, not shown, is located in the socket of the housing  2 . The ball and socket joint is sealingly enclosed by a sealing bellows  1 . The sealing space is enclosed by the packing and the jacket  1   b , and the two edges  1   a  and  1   c  of the sealing bellows are sealingly in contact with the housing  2 , which consists mostly of metal, and the pivot  4 . The edges  1   a  and  1   c  of the sealing bellows are made in one piece with the jacket  1   b . The edge  1   a  of the sealing bellows has a cylindrical inner surface, around which a sealing ring  3  is prepared by injection, bonded or tacked. On its radially inwardly facing side, the sealing ring  3  has teeth  3   a  extending in a circular pattern, which cooperate with the likewise circularly extending teeth  2   a  of the housing  2 . The teeth  3   a  of the sealing ring  3  are sawtooth-shaped, so that the sealing bellows  1  can be pushed over the housing  2  in the direction of the arrow relatively without problems, but it cannot unintentionally slip off same. The teeth  2   a  of the housing  2  are arranged on a collar-like projection  2   b  of the housing, and the teeth  2   a  point radially outwardly. The housing  2  forms a limitation with the wall  2   c  arranged at the collar-like projection  2   b , and the limitation prevents the teeth  3   a  from being unintentionally displaced farther in the direction of the arrow in the assembled state. The sealing ring  3  as well as the edge  1   c  of the sealing bellows are made of an elastic material, as a result of which a pretension can be achieved in the radial direction, which allows the teeth of the sets of teeth to firmly engage each other. Due to the sawtooth structure, the teeth act like a snap connection. The other edge  1   c  of the sealing bellows has sealing lips  1   c ′, which are sealingly in contact with the surface  4   a  of the pivot  4 . A sealing ring  5  is located in a correspondingly shaped, circular groove  1   c ″ of the edge  1   c  of the sealing bellows and generates a centripetal pressing force for the sealing lips  1   c ′, so that reliable sealing is obtained between the pivot  4  and the sealing bellows  1  against moisture and dirt. The jacket  1   b  of the sealing bellows is likewise made of an elastic material, so that the pivot  4  and the housing  2  can move in relation to each other. 
     FIG. 3  shows an optional straining ring  7 , which applies an additional force in the centripetal direction to the sealing teeth  3   a ,  2   a . As a result, stronger sealing is achieved by the teeth meshing with each other more strongly. It is, of course, possible for the edge  1   a  of the sealing bellows to have a circular groove for receiving and securing the straining ring  7  in the axial direction on its radially outwardly pointing side. The additional straining ring  7  is used to further improve the sealing and does not represent a turning away from the original idea of the invention. 
     FIG. 4  shows another alternative embodiment, in which an additional sealing ring  8  is arranged at a projection  2   b  of the housing  2 . With its radially inwardly pointing jacket surface, the sealing ring  8  is in contact with the projection  2   b . The projection  2   b  may form a circular groove, in which the additional sealing ring  8  can be seated secured in the axial direction. The sealing ring  8  may be optionally bonded, welded or tacked to the housing  2 . However, it is also possible for the sealing ring  8  to be prepared by injection molding or vulcanization in one piece. On its radially outwardly pointing side, the sealing ring  8  has circular teeth  8   a , which cooperate with the teeth  3   a  of the sealing bellows  1 . The sealing ring  8  may be made, e.g., of metal, rubber or plastic, especially a thermoplastic elastomer (TPE). 
     FIG. 5  shows another design of the embodiment according to  FIGS. 1 and 2 , in which the sealing ring  3  has a ring  9  incorporated by injection molding or vulcanization. The ring  9  may be, e.g., a metal ring for reinforcement. 
   It applies to all the above-described exemplary embodiments that the teeth may be greased. It is advantageously achieved hereby that the sealing bellows  1  can be pushed more easily over the housing  2  because of the reduced friction. In addition, better sealing action is achieved hereby. However, because of the teeth, the grease has no adverse effect on the locking of the teeth in the assembled state. 
   It also applies to all the above-described exemplary embodiments that the teeth are preferably made by means of plastic as the material, and that the sealing bellows is made of rubber. It is, of course, also possible to select other combinations of materials if this is necessary for the particular intended use. 
   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.