Variation of rolling element bearing friction torque

The statistical characteristics of the rolling element bearing friction torque are analyzed to find its evolvement law, via the experiment on the friction torque of two kinds of the bearings code-named HKTA and HKTB under the condition of different rotational speeds. A concept, relative increment of the variation coefficient, is proposed for an in-depth study of the evolvement course. According to the statistical calculating results for the experimental data, the higher the rotational speed of the rolling element bearing is, the severer the variation of its friction torque is. Under the condition of the low rotational speed range from 3r/min to 15r/min, the maximum of the relative increment of the variation coefficient can be over 25%. This uncovers new evidence that the degree of the evolvement of the friction torque will become stronger and stronger consequentially with the increase of the rotational speed of the rolling element bearing.