Abstract: The generating principle for the tooth profile of helical noncircular gear is introduced. By using the kinematics method, the meshing theory analysis model for the manufacturing of helical noncircular gear with movable axes and vari-able-transmission-ratio is established. Numerical analysis for the transverse profile, the section shape of tooth at the centrode cylinder and the contact line of the work gear are accomplished. It is proved that the tooth profile of helical noncircular gear is a ruled surface, that the section shape at the centrode cylinder (tooth trace) is a helix with constant angle and that the contact line in the paralled helical noncircular gear drive is a straight line.

Key words: Helical gear, Manufacturing, Non-circular gear