Analysis of the transmission ratio and efficiency ranges of the four-, five-, and six-link planetary gear trains

The objective of the present work was the conjoint analysis of the efficiency and transmission ratio ranges that can be achieved with all the possible constructive solutions of four-, five-, and six-link planetary gear trains. We started from the graphs of these trains to determine all the structurally distinct kinematic inversions. We then obtained all the constructive solutions resulting from every possible combination of gear type and configuration. The result was thus the set of structurally and constructively different planetary gear trains. Next, we obtained the range of transmission ratio that can be achieved with each train, and the efficiency as a function of the transmission ratios within that range. This analysis revealed which trains allow both high transmission ratios and high efficiency, and are thus potentially most useful in the design of power transmission applications. They included a series of high efficiency trains whose potential utility had not as yet been investigated. Additionally, the study led to some interesting conclusions about the relationship between efficiency and transmission ratio in six-link planetary gear trains.