上海充通大学 Velocity ratio for fix-axis gear train ☑ i5= 0= N:NNNs 05 NNzNsN 2 5 Direction！ Product of all b's Tooth Numbers iab= Product of all a's Tooth Numbers B-B.14 Product of all Tooth Numbers Product of all Tooth Numbers a' s b' s iab  1 2' 3' 4 2 3 4 5 5 1 15 N N N N N N N N i     Direction！ Velocity ratio for fix-axis gear train