歯車のかみ合い：西オーストラリア大学のWebより

http://www-mdp.eng.cam.ac.uk/web/library/enginfo/textbooks_dvd_only/DAN/intro/contents.html

The animation shows clearly : the contact point marching along the line of action the path of contact bounded by the two addenda the orthogonality between line of action and involute tooth flanks at the contact point how load is transferred from one pair of contacting teeth to the next as rotation proceeds relative sliding between the teeth - particularly noticable at the beginning and end of contact guaranteed tooth tip clearance due to the dedendum exceeding the addendum a significant gap between the non-drive face of a pinion tooth and the adjacent wheel tooth Gears formed by a milling cutter instead of being generated by a rack cutter as above, may exhibit undercutting or interference (which prevents complete rotation of the two gears due to teeth binding) - these faults result from Q2 for example lying to the left of T1 in Fig J.