Hybrid bearings for professional hand tools

SKF has selected a range of grease-lubricated hybrid bearings that are suitable for the repair and upgrading of high-speed hand tools powered by:

  • Air-turbine motors
  • Electric motors
  • Pneumatic motors

Hybrid bearings have inner and outer rings manufactured from bearing steel together with rolling elements made of bearing grade silicon nitride. The silicon nitride ceramic material 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 professional hand tools.

Hybrid bearings give improved service life 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

For professional hand tools SKF hybrid bearings can often be used at higher speeds than the SKF General Catalogue speed rating for all steel bearings. 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% less than of a steel ball at the same speed. Higher centrifugal loads cause higher bearing temperatures.
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