Patent Publication Number: US-6988830-B2

Title: Spherical plain bearing

Description:
This application is a continuation of PCT/EP2003/011464 FILED Oct. 16, 2003. 

   FIELD OF THE INVENTION 
   The invention concerns a spherical plain bearing comprising an inner ring configured as a spherical body comprising a through-bore, which inner ring is mounted in an outer ring through a slide bushing that surrounds the inner ring, said outer ring comprising a spherical inner surface and two diametrically opposite insertion grooves that start from an end face of the outer ring and enable insertion of the inner ring. 
   BACKGROUND OF THE INVENTION 
   In spherical plain bearings in which the spherical shape in the outer ring and the spherical shape on the slide bushing is made by shaping through axial upsetting of the outer ring, a high degree of deformation in the inner region of the outer ring can lead to cracking. Spherical plain bearings with an inner ring mounted for tilting in the outer ring are often not maintenance-free and therefore require regular re-lubrication. 
   A spherical plain bearing of the pre-cited type is known from the published patent application DE 1 903 422. The outer ring of this bearing is made up of three separate parts, viz. two flat disks that are connected to each other through an intermediate ring, for instance by welding or gluing. The diameter of the intermediate ring is larger than the diameter of the spherical body that constitutes the inner ring. After the insertion of the spherical body into the outer ring, the intermediate space between the spherical body and the intermediate ring is filled with a plastic so as to form a slide bushing. However, already due to the plurality of components of the outer ring, the fabrication of this spherical plain bearing is very complex. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to provide a simple and reliable means for making a spherical plain bearing comprising an additional sliding bearing lining. 
   This and other objects and advantages of the invention will become obvious from the following detailed description. 
   SUMMARY OF THE INVENTION 
   The invention achieves the above objects by the fact that, prior to the insertion of the inner ring into the outer ring, the slide bushing is slipped onto the inner ring and then shaped without chip removal, so that the slide bushing comes to bear against a spherical outer surface of the inner ring. In this way, crack formation on the outer ring due to axial upsetting is avoided and a maintenance-free spherical plain bearing is created that permits any desired outer contour, for example, a double or a triple flange contour. 
   The slide bushing can be made to bear against the spherical inner ring by roller-burnishing or pressing. 
   Stampings extending into regions of the insertion grooves of the outer ring can be made on the slide bushing to prevent it from rotating. The outer ring can be made of a sintered steel. 
   The invention will now be described more closely with reference to the appended drawing that shows one example of embodiment. 

   
     BRIEF DESCRIPTION OF THE DRAWING 
       FIG. 1  shows an outer ring of a bearing of the invention; 
       FIG. 2  shows an inner ring of the bearing of the invention, with a slide bushing slipped onto the inner ring; 
       FIG. 3  shows the bearing of the invention, with the inner ring inserted but not yet pivoted; 
       FIG. 4  shows the ready-assembled bearing of the invention. 
   

   DETAILED DESCRIPTION OF THE DRAWING 
   A spherical plain bearing of the invention comprises an outer ring  1 , an inner ring  2  and a slide bushing  3 . The outer surface of the inner ring  2  is spherical in shape. Corresponding to this, the inner surface of the outer ring  1  has the shape of a spherical shell. The slide bushing  3  is slipped onto the inner ring  2  and brought to bear against the inner ring  2  by shaping without chip removal. In order to be able to insert this assembled unit made up of the inner ring  2  and the slide bushing  3  into the outer ring  1 , two diametrically opposite insertion grooves  4  are arranged on the outer ring  1  starting from one of its end faces. 
   As shown in  FIG. 3 , the slide bushing  3  and the inner ring  2  are inserted at first with a part of the periphery foremost into the outer ring  1  in the axial direction of the outer ring  1  and then pivoted through 90°, so that the outer ring  1 , the slide bushing  3  and the inner ring  2  get arranged coaxially. Following this, the slide bushing  3  is deformed, so that stamped portions  5  that project into the two insertion grooves  4  of the outer ring  1  are formed on the slide bushing  3  and prevent a rotation of the slide bushing  3  relative to the outer ring  1 . The inner ring  2  is thus mounted through the slide bushing  3  for rotation in the outer ring  1  and can pivot within limits in keeping with its spherical shape.