Torque/Speed Investigations on Ball Bearings for Reaction Wheels

摘要

The torque behavior from 0 to 4500 rpm of angular contact bearings (15 mm and 20 mm bore) with respect to lubricant type, lubricant quantity and cage design was investigated. With 15mm bearings, torque rises with increasing speed for all the test oils and little effect of cage design is observed. With 20 mm bearings, KG80 and Fomblin Z25 oil give pronounced torque minima at high speeds and the torque/speed graph is a function of the cage design. Inner race riding cages can give rise to incomplete elastohydrodynamic (EHD) lubrication. The triester oil BP135 does not provide complete EHD lubrication at any speed up to 4500 rpm with either bearing size. Results for KG80 and Z25 in 20 mm bearings are anomalous; torque minima are also observed at intermediate speeds.