Uncertainty and its Evolvement of Rolling Element Bearing Friction Torque

Based on the information poor system theory, the concepts, viz., the measure, the standard deviation, and variation coefficient of the mean of the fluctuant ranges, were proposed to study the relationship between the uncertainty of the friction torque and the rotational speed of the rolling element bearing. The uncertainty was investigated using the measure to describe its size, using the standard deviation to depict its fluctuant state, and using the variation coefficient to character its evolutive history. The experiments on two types of the rolling element bearings, HKTA and HKTB, indicate that for the uncertainty of the friction torque, as the rotational speed is raised the value of its measure increases and both its fluctuant state and evolutive history present the trends of the nonlinearly fluctuant change.