Inspection and analysis of the functioning of the bearings used on railways : a study of the life of a bearing under real operating conditions

Abstract

The objective of the present work is to carry out an analysis of the performance and life of bearings used in railways transporting ore. The project determined the nominal life (L10) for a single type of bearing commonly used in railways (SKF CTBU Class K and Timken AP-2TM). To do so, it considered two methodologies. Methodology I is an alternative approach proposed by a few authors in Brazil, inspired by a procedure used to design rail shafts. Methodology II is based on well-established techniques proposed by the bearing manufacturers (as SKF and Timken). After of have estimated L10, is determined the bearing lifetime (L) using two correction parameters (one based on reliability (a1 ) and the other based on the working conditions of the bearing(a ISO) This in order to determine whether it was being replaced at the appropriate time, to improve its replacement periods, decrease maintenance costs, make the most of the life of the bearing and detect possible causes of faults it may present at any given time. In addition, it discusses some Condition Monitoring Techniques that can help identify anomalies, faults and breakdowns in these bearings. It touches on the phenomenon of electric current through wheel bearings, the way to identify, detect and prevent it, and some measurement techniques. Finally, it explains in detail the bearings process reconditioning (mounting, dismounting and reconditioning) that accomplished some companies in order to maximize the life of these.