During process of designing noncircular planetary gearing system, one of the most important tasks is synthesis of pitch lines of the gears with condition of preserving correct transmission function. In this work, the author presents a method for synthesizing pitch line of the noncircular planetary gearing system based on given pitch line of the planetary gear. In comparison with previous experience-based methods, this work also sets the condition for the pitch line of the second sun gear, which will cover all the inside planetary gears. Moreover, the author proposes a synthesizing process of the pitch lines of the noncircular planetary gearing system.
