Abstract: Based on meshing theory of Hy-Vo silent chain and sprocket and rotary cutting principles of the sprocket hob and sprocket, the new design philosophy of making the Hy-Vo silent chain plate profile as the hob normal tooth, a meshing design system of Hy-Vo silent chain based on heart hole-sprocket-tool rock is established. According to the conjugate meshing condition of Hy-Vo silent chain sprocket and tool rock, a meshing design method of parameters changing when the chain plate profile angle does not mean the involute chain sprocket pressure angle is presented, and also the example design calculation is done. The wear resistance characteristic of a new Hy-Vo silent chain has been studied based on the experiment on the test bench for 171 h. Because of the heart hole and evagination curves of the pin section, which can have more contact area, thus the new Hy-Vo silent chain has excellent wear resistance. Experimental studies show that the new meshing design system and design method is scientific and feasible.

Key words: Heart hole, Hy-Vo silent chain, Meshing design system, Parameters changing, Sprocket tool rock