Abstract: Based on the study of the variable pitch characteristic of new Hy-Vo silent chain, the notion of virtual side-center distance is brought up, and the design principle of the fixed position angular displacement is pointed out. By studying the meshing theory of new Hy-Vo silent chain and sprockets and the rolling cutting machining theory of sprocket and hob, the harmonious relations of dominating design parameters among new Hy-Vo silent chain, sprocket and hob is built, and the resolved expressions that can instruct designing and calculation are brought up. The test study shows that the new design method is feasible.

Key words: Meshing theory, Modification coefficient, New Hy-Vo silent chain, Sprocket hob, Variable pitch, Virtual side-center distance