Abstract: In the past Soma research works on the meshing theory of cylindrical worm drive with nonlinear surface have been carried out[6]-[12],but they are not very satisfactory, especially on the calculating formulas of limiting curves of the first kind and the second kind as well as the induced normal curvature. Up to now we have found nothing about it in the literatures and it is necessary to go more deeply into the researches on the meshing characteristics. All of these are the probems to be investigaetd in further studies of the mesting theory of cylindrical worm drive with nonlinear surface and it’s loading capacity. In this paper, refering to the gear meshing theory presented by NAN KAI University, We have dreived some calculating formulas involved and made some researches on the meshing characteristics and obtained some usful conclusions. As space is limited, the procedure of the calaculating formulas are not given in detail. Except for special notice, the procedure of the formulas can be found in the article[22].

Key words: Global symmetry, Inter-part symmetry, Intra-part symmetry, Part sets classification, Symmetry merging, Assembly model