Spherical roller bearings

Spherical roller bearings have two rows of rollers, a common sphered outer ring raceway and two inner ring raceways inclined at an angle to the bearing axis (fig. 1.) The centre point of the sphere in the outer ring raceway is at the bearing axis. Therefore, the bearings are self-aligning (fig. 2) and insensitive to misalignment of the shaft relative to the housing, which can be caused, for example, by shaft deflection. Spherical roller bearings are designed to accommodate heavy radial loads, as well as heavy axial loads in both directions.
Bearing performance is not only determined by load or speed ratings. There are a number of other factors that contribute to bearing performance. To a large extent, performance is influenced by the geometry of the rollers, raceways and cages, the heat treatment, as well as the surface finish of all contact surfaces. Main factors which influence SKF spherical roller bearing performance include, but are not limited to:
  • Symmetrical rollers
    Symmetrical rollers self-adjust (fig. 3), providing optimal load distribution along the roller length. This keeps stresses low under all load conditions and extends bearing service life.
  • Roller tolerances
    The rollers in an SKF spherical roller bearing are manufactured to extremely tight tolerances for dimension and form. Each roller is virtually identical in size and shape to the other rollers in the set. This optimizes load distribution over the rollers to maximize bearing service life.
  • Special roller profile
    The roller profile determines the stress distribution in the roller/raceway contact area. The special profile distributes loads more evenly along the rollers and prevents stress peaks at the roller ends to extend bearing service life (fig. 4).
  • Self-guiding rollers and a floating guide ring between the two rows of rollers
    Self-guiding rollers reduce friction and frictional heat (fig. 5). A floating guide ring guides unloaded rollers so that they enter the load zone in the optimal position.
  • Metal cages
    All SKF spherical roller bearings contain strong metal cages. This enables them to tolerate high temperatures and all lubricants.