Based on the simulated test on TIMKEN friction-wear testing machine and the practical test on transmission testing table,systematically deals with the most carrying capacity and the limit load of steel worm-gearing with three kinds of lubricant and four kinds of hardness difference of tooth face.

Forming principle of tooth flank of modified toroidaldouble enveloping worm gear pair;

The application of methods of orthogonal test and analysis to defind the combination of parameteres in setting up formulas of transmission accuracy of cylidrical worm gear pair offers a shot cut in finding out the major effecting geometric parameters of cylindrical worm gear pair.

xperiments on tribological performance have been made with couples of worm gear with 10 different combinations of material.