Study On The Friction Torque Characteristics Of Angular Contact Ball Bearings

An angular contact ball bearing is one of the main supporting parts in the high-speed motorized spindle. Its performance has great influence on the accuracy, efficiency and working life of a motorized spindle. The friction torque is an important performance parameter of bearing. It represents an energy loss and causes a retardation of motion, hence it is witnessed as a temperature increase. Hence, it has important theoretical significance and practical application to systematically analyze the bearing friction torque in improving the spindle work efficiency and ensuring the whole mechanical properties.On the basis of the experiments in B719series of angular contact ball bearings, the effects of the rotational speed, load, working temperature and itself structure parameter on friction torque are studied. Based on the grey system theory, the model of the grey relation analysis is established to study the influence degree on the friction torque in various influencing factors. Several key factors are selected to build the GM(1,N,D) model. It can predicate the friction torque in some condition. In addition, the several key factors are used to build the nonlinear NARMAX model to dynamically identify the friction torque system.The result of the grey relation analysis show that, compared with other influence factors, inner diameter of bearing, temperature, axial load and speed have significant effect upon the bearing friction torque. Among them, the grey relational grade of inner diameter has most influence. Four key factors are selected to build the GM(1,N,D) model. Verified by the experiment, the accuracy of GM(1,N,D) model is97.7%and the average relative residuals is2.3%. The identification result of the nonlinear NARMAX model agrees with the experimental result basically. The accuracy is87.67%and the average residual error is12.23%. These models can server as a reference in analyzing friction torque of a angular contact ball bearing.