Most bearing arrangements must be sealed to prevent contaminants, such as dirt and moisture, from entering the bearing. The efficiency of the seal has a decisive influence on the service life of the bearing. In contrast to most other bearing types, which only move in one plane, the alignment capabilities of spherical plain bearings place additional demands on the seal.

To select appropriate seals, several factors have to be considered, including:

  • the permissible angle of tilt
  • the available space
  • environmental conditions
  • the effectiveness of the seal
  • the type of lubricant and the frequency of relubrication
  • the justifiable cost

Depending on the application, one or more of the above factors outweigh the others. It is therefore not possible to establish general rules for seal design.

Most SKF radial spherical plain bearing series are available with integral seals. Standard sealed bearings can increase the service life of the bearings and save space, while reducing inventory and assembly costs. Design characteristics and suitability of the RS seals and the LS heavy-duty seals are provided in table 1.

Table 2 provides an overview of external sealing possibilities, their design characteristics and their suitability to meet different application requirements. SKF supplies most of the external seals introduced in table 2.
SKF additional information about the seals referred to in table 2, refer to
SKF also supplies sealing strips made of felt (FS strips) or aluminium-boron silicate (FSB strips) for high temperature applications.
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