Machinery Lubrication magazine published by Noria Corporation
Issue link: http://www.e-digitaleditions.com/i/934530
Rolling-element bearings are some of the most frequently used mechanical components that require a lubricant. eir application is very broad, ranging from small, non-critical knob-adjuster support bearings to large, critical wind-turbine main bearings. In general, bearings tend to fail well before their design life. is is often because the environmental and operating factors are not controlled or taken into consideration when the lubricant is selected. In this article, I will refer to rolling-element bear- ings simply as bearings. However, this does not necessarily address the topic as it relates to journal bearings. Regardless of whether a bearing reaches its design life, the life you should strive to achieve from your bearings should be based on the optimum reference state (ORS). When considering a bearing's application and its associ- ated reliability objectives, a certain maintenance strategy should be deployed to help attain an optimized return on investment. For example, if the result of a bearing failure does not lead to any immediate downtime and the corrective action costs are insignificant when compared to using regular proactive and predictive maintenance over the life of the bearing, then a run-to-failure strategy may be the ORS. It's not uncommon for small bearings (with low speed factors) to be kept sealed without any relubrication and very little maintenance required. However, in most cases, a carefully selected relubrication schedule and a mainte- nance strategy that is more comprehensive than simply reactive maintenance will be recommended, depending on the optimum reference state. When performing a failure modes and effects analysis (FMEA) on a bearing, a series of questions must be asked. ese would include the following: 8 Lubrication Failure Mechanisms for Rolling-element Bearings 34 | January - February 2018 | www . machinerylubrication.com B earing Lubric ation LESSONS IN LUBRICATION Bennett Fitch | Noria Corporation Whether it's excessive contamination or an incorrectly applied lubricant, it is important to understand the root causes that can contribute to lubrication failure mechanisms." "