GENSIM - a compact regression-based model for Coulomb torque in ball bearings

A computable model is described for estimating Coulomb (frictional) torque of a ball bearing under free rolling conditions. The model assumes complete microslip over the contact and makes use of precalculated polynomial regressions to approximate the roll and spin moments and the lateral traction force at each contact. Iterative solution of the force and moment balance equations (with only two unknowns) then allows the Coulomb torque to be found. Use of regressions in this way makes the model compact and efficient at dealing with a wide range of rotational speeds and contact geometries. The range of validity of the model is discussed. From the so-far limited number of field trials, good agreement exists with other codes and experimental data.