Dynamic behavior simulation of a worm gear

A global model is necessary to understand and improve the dynamic behavior of electric power steering (EPS) systems. This paper presents the transient response of a worm gear under harmonic excitation. The gear model is formulated by extending the method used for Spur gears and is based on the lumped parameter theory. Backlash clearances and error excitation are taken into account. It is also possible to couple axial, lateral and torsional motions. To avoid numerical problems encountered with direct numerical integration, meshing stiffness and damping, which are often considered as piecewise linear functions owing to backlash. are approached by a continuous function. The effects of several parameters Such as mesh stiffness, damping values and backlash value are analyzed. Certain discontinuities are shown to exist in the accelerations of both wheel and worm centers due to impacts between the gear pair.