SKIDDING ANALYSIS OF HIGH-SPEED AND LIGHT-LOAD ROLLER BEARING BASED ON MODIFIED FILM THICKNESS FORMULA AND CONSIDERING BEARING WHIRL WITH ELLIPTICAL ORBIT

摘要

In order to obtain the more accurate film thickness formula to assist in the skidding analysis of high-speed and light-load roller bearings (HSLLRBs), the oil film characteristics of HSLLRBs under slip conditions were analysed. Moreover, the ellipse is adopted to be the whirl orbits, which is more close to real whirling orbit than the circular orbit in practice. Based on the oil film thickness modified formula, an analytical model was built by taking bearing whirl with elliptical orbit into account, and the skidding mechanism was investigated in terms of various factors such as whirl orbit, radial load, lubricating oil viscosity and roller diameter. The results showed that whirl often exacerbates skidding failure to HSLLRBs, and the degree of skidding is directly correlated with the whirl radius, especially the X-radius. Effects of different oil film thickness formulas on skidding of rolling bearing are different, Dowson 1977 modified film thickness formula is more fit to provide assistance in the skidding analysis of HSLLRBs. As radial load increase or the roller diameter decrease, the influence of whirling on bearing skid and the degree of skidding decrease. Therefore, for minishing skid so as to improve HSLLRBs service life and reliability, the whirl radius (especially the X-radius) and roller diameter should be decreased, whereas the radial load should be increased moderately. The final purpose of this study is to support the failure mechanism and vibration analysis of HSLLRBs.