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In order to investigate the behaviour of worm drives, a new dynamic model, composed of two blocks, is established and used to extract numerical results. The tooth deflection of the worm drive, bearings, and wheels inertias are taken into consideration. Newmark solving method is applied to solve motion equations. The state of contact of teeth is what enables these signals to manifest themselves. Modal analysis is developed to investigate the different natural modes of the model. Furthermore, modal energetic analysis is used to understand the distribution of strain and kinetic energies. It is also applied to classify natural models into “teeth modes” and “bearing modes”. These two modes constitute two different frequency bands. The dynamic coefficient is measured simultaneously with the gradual increase of the turning speed of the motor. This allows for the evaluation of the overload of the system.

Background: Worm gear sets are used in many applications of the transmission field. These mechanisms have interesting advantages. Despite this, its modelization is still challenging. This is due to its complex geometry. The goal behind this is to have an accurate model that allows improvement of the design of worm gear sets. Purpose: In this context, the paper presents a new mathematical model of a worm gear drive under rotational external excitations. Methods: Dynamic model is defined by fourteen degrees of freedom describing all rotations and translations of worm gear set, AQ1 bearings, a motor and a receiver connected together. First, equations of motion are developed to describe the dynamic behavior. Lagrange formula is, thus, employed. Elastic deformations of meshed teeth are considered. The normal load associated with the meshing is established as function of the model degrees of freedom through the elastic deflection. Second, a numerical simulation is carried out. Newmark Beta method is used to solve equations. Results: Numerical results are presented to discuss the model accuracy. The impact of the variation of friction coefficient and the stiffness of the worm gear is finally studied to discuss the consistency of the new formulation developed through this work. [ABSTRACT FROM AUTHOR]