Analysis And Optimization Of Slewing Ring’s Load-carrying Properties

Slewing ring, a special large-scale bearing, is one of the key components ofengineering machinery. It relies on rolling contact of rolling elements, inner and outerrings of the bearing to support the rotating parts and transmit forces and motion．Therefore， the contact problem is the basis of studying slewing bearings whichdirectly affect the carrying capacity and service life of slewing rings． The contactproblem is a highly nonlinear problem． Theoretical calculations, finite elementanalysis and testing are used to study the contact problem of single-row four-pointcontact ball slewing bearing and specific contents are as follows：（1）Hertz theory is the classical method to solve the contact problem of slewingring’s ball and track. On the basis of Hertz theory and contact mechanics, thedeformation and stress conditions of contact area are solved more comprehensively.The maximum stress and its location are obtained.（2）The contact condition are analyzed by the finite element software ABAQUS,which is an excellent software to deal with nonlinear problems. The results arecompared with the theoretical calculation. The deviation is small. Meanwhile, thedistribution of the slewing bearing is analyzed under the condition of overturningmoment. Compared with the theoretical calculation, the deviation is a little big. Thereason of the deviation is that the theoretical calculation is conservative and theresults by using finite element analysis is more reasonable.（3）The relationship between the raceway’s shape of the single-row four-pointcontact ball slewing bearing and its carrying capacity is studied and the slewingbearing is optimized based on the conclusion that the oval raceway’s shape cannotimprove the slewing bearing’s carrying capacity. The result of ABAQUS indicatesthat the optimized raceway could reduce the maximum contact stress between the balland the raceway by10%and the fatigue life is also increased by20%based on theFe-safe fatigue life analysis.(4)After induction hardening and high tempering,50Mn on slewing bearing ringsare conducted with metallurgical test and hardness distribution test. After inductionhardening and tempering, allowable contact stress of slewing bearing rings ismeasured by point contact tests of steel ball and42CrMo flat specimen. The curve regression equation is obtained between allowable contact stress and steel balldiameter ratio indentation depth.