Load distribution analysis method for cylindrical worm gear teeth

Worm gears provide large reduction ratios and low noise for their load capacities. However, owing to manufacturing errors and bending deflections under load, a worm and a wheel do not operate at their theoretical load during meshing. It is important to predict the load distribution considering the tooth profile and assembling error. A method for determining the load distribution, Hertzian contact pressure and oil film thickness is presented in this paper. Using our empirical formula for bending deflections, we developed the transformation matrix. The deflection along the load direction at any point on the contact line at the same meshing position is expressed by the matrix of transformation. Using this matrix, the load distribution of a worm and wheel is evaluated using numerical analysis. Calculated results clearly agree with experimental ones obtained under actual operating conditions.