Interference analysis of transition curve for the shaping of noncircular gears

The shaping process of non-circular gears consists of the manufacturing of internal non-circular gears and external non-circular gears according to the curvature character of pitch curves of non-circular gears. The essential differences between internal non-circular gear and external non-circular gear are clarified. The concept is proposed that a non-circular gear is composed of several cylindric gears with different teeth numbers, but same modular and same pressure angles. Thus, the Equivalent Teeth Number (ETN) is set forth. By using the analysis method of non-circular gear's ETN, the analysis of transition curve's interference of non-circular gears is transformed into that of cylindric gears. The transition curve's interference conditions are given. The effective method to avoid the transition curve's interference is given according to transition curve's interference conditions.