Loading Skewed Effect Analysis On Journal Bearings Of A Railway Wagon

Causes of earlier failures are investigated for journal bearings of railway wagons with35.7t axle weight. Nine loads sets are firstly deterimined by using balance force system of the wagon wheelset, in which dynamic load factors of the wagon are deterimined according to the codes of JIS E4501and EN13103. The nine loads sets include those distributed vertical load centers across through the adapter symestrical line and the eight deviation distances, i.e.1.8,2.7,4,10,15,20,25, and30mm, from the symestrical line. And then, bearing capacity and rated life L10with90percentage of survival probability are evaluated respectively by the comventional method of code ISO281and finite element method. Results reveal that(1) The bearing rated life is only569000km using loads by code JIS E4501, which is lower than the bearing life requirement of600000km for the railway vehicles with a veolocity lower than200km/h of the code EN12082. While the rated life is892900km using the loads by code EN13103, which meets the life requirement of600000km. But the loads by the code JIS E4501seem more closer to service conditions of the bearings of railway wagons rather than those by the code EN13103, because JIS E4501distinguishes detailedly line conditions and vehicle volocities. Therefore, the earlier failures of the bearing should be contributed somewhat from the wheaker capacity of the present bearings.(2) The analyzed results by the comventional method (CM) of ISO281exihibit the rated life of bearings decreasing with the deviation distance increasing. When the distance is at30mm, the life is decreased to about94%.(3) By the finite element method (FEM), the rated life tends to increase before the distance close to about2mm. And then, the life returns to decrease sensitively with the distance increase. When the distance is up to30mm, the life decreases to about70%. Therefore, FEM seems more sensitively to reflect the loading skewed effect.Present work provides a scientific basis of evaluating bearing capacity of railway wagons and controlling the loading deviation distance.