Global curvature characteristics analysis of offset ZI worm drive

A new contacting performance index, the global induced principal curvature (GIPC), is put forward in this paper, along with its calculation method. This new index can be used to analyze the global curvature characteristics within the conjugating region of the gearing, so that the contacting performance of the gearing can be understood. A novel type of gearing named offset ZI worm drive is laid out. The calculation method of this new index is applied to this novel type of gearing. The GIPC of this new gearing is calculated by the numerical method and verified by the analytical method; the global curvature characteristics are analyzed. The numerical results show that the absolute value of the GIPC of the e-flank is 52.2384% smaller than the i-flank, which indicates the contact stress level of the e-flank is lower than the i-flank. The maximum of the relative errors for the GIPC between the numerical method and the analytical method is −3.0380e-11%. The accuracy of the numerical method is high.