SKF hybrid bearings for high speed electric motors

SKF has selected a range of grease-lubricated single row deep groove ball bearings with ceramic balls that are especially suitable for:

  • air-turbine motors
  • electrical motors
  • pneumatic motors

Hybrid bearings have carbon-chromium steel rings and special grade Silicon Nitride rolling elements. The ceramic material silicon nitride is produced by a powder compacting process acting at high temperature (~1800°C) and high pressure (~200MPa). The SKF specified process creates a solid ceramic material without any porosity, and with good toughness.

This range of hybrid bearings offers a replacement to conventional all-steel grease-lubricated bearings in high speed Electric motors.

Improved service life can be achieved for hybrid bearings due to:

  • extended grease life
  • good performance in air-streams and condensation
  • high wear resistance against particulate contamination (sand, pigments, abrasives, steel, iron oxides etc)
  • resistance to electric current

Centrifugal forces in bearings

SKF hybrid bearings can often be used at higher speeds than the standard speed ratings for grease-lubricated standard deep groove ball bearings given in the SKF General Catalogue. This is due to the lower density of silicon nitride compared to steel. The centrifugal force from a ceramic ball in a bearing is 40% of that of a steel ball at the same speed. Higher centrifugal loads cause higher bearing temperatures.
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