Experimental And Theoretical Study On Ehl Of Thrust Ball Bearings

In this thesis, the thrust ball bearings were studied experimentally and theoretically.Under the conditions of low speed and even load, waviness of the bearing raceway andslip rate of the bearing were measured. Then based on the results, the influence ofraceway waviness and slip rate on bearing lubrication was studied experimentally.Thereafter the experimental results about the raceway wavines are simulatedtheoretically. The theoretical calculation agrees well with the experimental results. Atlast, the elastohydrodynamic lubrication (EHL) characteristics on reciprocating motionis explored theoretically.Firstly, the waviness on raceway of washer is measured using an opticalinterference technique on a custom-made test rig; then oil film thickness in onerevolution is measured. It is found that the raceway surface waviness influences thevariation of the oil film greatly.Secondly, the slip ratio of the thrust ball bearing is measured experimentally on thesame test rig. By analyzing the optical images, the revolution speed of the balls on thethrust ball bearing were measured quantitatively, and then the sliprate was calculated.Under the slip rate the film thickness was measured.Thirdly, based on the experimental results on the raceway waviness, theoreticalcalculations are carried out. The theoretical and experimental results agree quite wellwith each other. Subsequently the contacts between the balls and the raceway, which areimpossible to measure experimentally, are calculated theoretically.At last, the theoretical analysis is carried out on line contact reciprocating thermalEHL. The EHL characteristics are studied under loads of steady state, sine-wave andtriangular wave. Then, the influence of stoke length on the oil film characteristics undersine-type impulse loading was investigated.