Normal circular pitch Transverse circular pitch (a) =P,Cos攻 Section B-B Helix angle Axial pitch P Px= tan Normal diametral pitch (b) P= PTransverse diametral pitch cos cos女= tan中m Normal pressure angle tan -Transverse pressure ang (e) SectionA-A 上游文大学 FANGHAI HO TONG UNIVERSITY Φn cos= tan n tan7 Normal circular pitch Transverse circular pitch Helix angle Axial pitch Normal diametral pitch Transverse diametral pitch Normal pressure angle Transverse pressure ang Φn h A' C O ' h Φt O A ψ