Abstract: Non-backlash double-roller enveloping hourglass worm gearing is a new-type hourglass worm gearing, which can be used in high precision and big load applications domain. To obtain a non-backlash double-roller enveloping hourglass worm gearing with perfect meshing performance, the optimization design of the worm gearing is presented with the contact and lubrication performances of the gearing taken into consideration. By numerical calculation of the tooth contact parameters that includes lubrication angle, induced normal curvature, entrainment velocity and roller rotation angle, the effect factor of the meshing performance are discussed and the value range of design variables is determined. Then, the optimization model of the worm gearing is built, in which the roller rotation angle and comprehensive coefficient of tooth for elastohydrodynamic lubrication condition are taken as optimization objectives, and the lubrication angle, the strength and stiffness of the worm axis and geometric non-interference are considered as constraint conditions. The GA toolbox in the Matlab software is utilized to obtain the optimal solution. A numerical example shows that this method can be used to effectively improve the meshing performance of the non-backlash double-roller enveloping hourglass worm gearing.

Key words: Double-roller, Hourglass worm gearing, Meshing performance, Non-backlash, Optimization design