本文利用转化原理和现行计算行星轮系和定轴轮系传动比的方法,提出了计算闭式行星轮系传动比的公式,并应用于设计.方法简便可行,有一定的理论和实用价值. In this paper, by using the principle of transformation and the current method of calculating the gear ratios of planetary gear sets and fixed gear sets, a formula to calculate the gear ratio of the closed planetary gear set is proposed and applied to the design.The method is simple and feasible and has certain theoretical and practical value.