SIMULATION OF CONE BORE GROWTH IN BEARINGS WITH A 3-RING MODEL

Cone bore growth in case-carburized bearings was modeled by incorporat ing the mechanisms of thermal-induced phase transformation and low tem perature creep in an approximate model of the cone. The inner case, co re, and outer case regions of the bearing cone are modeled bu three co ncentric rings. Using a mechanics of materials approach with the aid o f some simplifying assumptions ( i.e., radial stresses remain zero thr oughout the ring thickness and net circumferential strain is the same for all three rings), the influence of temperature, interference fit s tresses, initial case carburizing stresses, and stress relaxation on t he change in bore diameter and circumferential stress during service c ould be determined. The model indicated that both thermal-induced tran sformation and low temperature creep may play a role in bore growth du ring service. As temperature was increased from 70 degrees C to 200 de grees C, the susceptibility to bore growth became greater. Also, an in crease in the interference fit increased the initial cone bore growth rate. In addition, the effect of the recondition treatment on the bore diameter and residual stresses was studied. The bore diameter general ly decreased during the recondition treatment, and this was attributed to the relaxation of residual stresses by low temperature creep.