In this study, a simplified method for evaluating amount of deflection for the tooth of worm and worm gear under loading is proposed. In a previous study, the plate theory was used for the approximation. However, it was found that the deflection of gear tooth using the plate theory was far from the actual value, and that the values from 3D FE analyses were closer to the actual value than from the plate theory. However, the FE analysis process starting from the CAD model to the final analysis results is complicated and too time-consuming. Therefore, the form factors are needed to facilitate simple but accurate results for the design purpose. In this study, the equations of form factors obtained from the results of plate theory and the 3D FEM, are developed. Since the worm gear assembly has various tooth geometries, the moment of inertia and the deflection of tooth geometry are different. Therefore, tooth geometries with trapezoid and involute forms are investigated.
