ENDURANCE AND FAILURE CHARACTERISTIC OF MAIN-SHAFT JET ENGINE BEARINGS AT 3xl06 DN

摘要

Groups of thirty 120-mm bore angular-contact ball bearings were endurance tested at a speed of 12 000 and 25 000 rpm (1. 44xl06 and 3. OxlO6 DN) and a thrust load of 66 721 N (5000 lb). The bearings were manufactured from a single heat of VIM-VAR AISI M-50 steel. At 1. 44xl06 and 3. OxlO6 DN, 84, 483 and 74 800 bearing test hours were accumulated, respectively. Test results were compared with sim¬ilar bearings made from CVM AISI M-50 steel run under the same conditions. Bearing lives at speeds of 3xl06 DN with the VIM-VAR AISI M-50 steel were nearly equivalent to those obtained at lower speeds. A combined processing and material life factor of 44 was found for VIM-VAR AISI M-50 steel. Continuous running after a spall has occurred at 3. 0x10" DN can result in a destructive fracture of the bear¬ing inner race.