Análise de adesão de graxas em roda e trilho

Abstract

In the wheel-rail contact, friction, wear and noise are generated, being the most severe situations in tight curves, where there is a greater demand for lateral effort. In order to reduce the lateral wear of the rail, fixed lubricators are used, which store and pump the lubricating grease to the side of the rail, doing the lubrication work when contact with the wheel flange occurs. Lubricant retentivity can be determined by analyzing parameters such as tackiness and critical speed at which grease is ejected from the wheel flange. This analysis contributes to the reduction of wear and can assist in the selection of greases with adequate performance under specific operating conditions. In order to study these parameters, the present work aims to define a methodology for analyzing tackiness and critical speed of lubricating greases, and also to analyze the influence of different thickeners and viscosity on their performance. Based on the tests, the results showed that lithium greases performed better in both tests. It was also observed that at low viscosities, the thickener did not influence the performance of the greases. And, for retentivity, the determining parameter is the thickness in which the grease is deposited, regardless of the thickener or viscosity.