Transfer lubrication of rolling bearings

The general subject of transfer has been described in Chapter 8. Composites used specifically for transfer lubrication do not need the structural strength which is needed for the construction of load-bearing components. Some structural strength is of course needed to maintain the integrity of the composite reservoir. This may be very low where the reservoir is contained in a recess in a metallic or ceramic component, so that the structural strength is provided by the surrounding material. 

Some examples of the practical use of transfer lubrication in a piston engine 

The retainer may be completely fabricated from a composite material, or may consist mainly of a composite with reinforcement by metal rings. Alternatively it may be conventionally fabricated of steel or other suitable metals, with composite components bonded, rivetted or pressed onto it, or with holes or grooves filled with the lubricant composite. 

Many hundreds of different composite compositions have been tested for use in ball or roller bearings, mainly for space use. Some examples of results with polymer-based composites are shown in Table 12.11 and with metailic compacts in Table 12.12. Among the polymeric composites the best results have been reported with composites of PTFE or polyimide. Bearings are commercially available with composite retainers based on either polymer. 

Bearing Type Retainer Materials Load RPM Environment Life Ref 

---