0 Introduction There are a number of meshing drives with line contact tooth surfaces in engineering. Errors will appear in drive elements manufacturing and assembling processes, and the contact state will be changed from theoretic line contact to point, which will lead to the meshing state becoming bad, not our desired ideal situation. Generally speaking, machining errors of elements are closely associated with actual factors such as technological processes, manufacturing facilities, and operator's technique. Their improvement and enhancement is difficult and expensive. It is
