A METHOD TO IDENTIFY MODAL PARAMETERS AND GEAR ERRORS BY VIBRATIONS OF A SPUR GEAR PAIR

Abstract

A new method to identify modal parameters (natural frequency and damping) and the equivalent gear error of a spur gear pair is introduced. The equivalent error is a function of the gear position and is related to the errors of the driving and the driven gears and to the non-dimensional stiffness of the teeth. The method is based on the measurement of the gear torsional vibrations. The test rig is modelled as a single-degree-of-freedom system and must be assembled by using stiff bearings and torsionally compliant shafts. The solution of the equation of motion is obtained through the harmonic balance method. The proposed approach has some advantages with respect to traditional metrological methods. The effect of noise on the accuracy of the identification is also investigated and discussed. Applications of the method to the identification of natural frequency, damping and profile errors are shown.