PARAMETER-IDENTIFICATION OF HYSTERESIS FRICTION FOR COATED BALL-BEARINGS BASED ON 3-DIMENSIONAL FEM ANALYSIS

Using a three-dimensional finite element model, the hysteresis frictio n behavior of coated ball bearings is investigated. Ninety-sire distin ct operating conditions were examined by the finite element model that include normal loads of 81.6, 133.5, and 185.4 N per ball, ball diame ters of .0127 m and .0191 m, ball materials of Si3N4 and steel, substr ate materials of Si3N4 and steel, and coating materials of MoS2, NbSe2 , Si3N4, and steel. From the finite element results, general trends fo r the two parameters of Dahl's friction model, the rest slope, sigma, and the steady friction torque, T-s, are established for coated surfac es. By performing a regression analysis of the data points, empirical expressions for a and T-s are derived for coated bearing surfaces. The se expressions are authenticated by comparisons to laboratory experime ntal results.