ABSTRACT
This chapter presents a method of calculating planetary speed ratios and power flows. It discusses load sharing, assembly, and choice of numbers of teeth and numbers of planets. A planetary gear train is one in which the power is transmitted through two or more load paths rather than the single load path of a simple gear mesh. In the United States, planetary gears are widely utilized in automotive automatic transmissions and in aerospace drives such as turbine engine reduction gears or helicopter transmissions but are not used extensively in industrial applications. Planetary gears can be arranged in a multitude of configurations to achieve specific ratios and power splits. An interesting planetary arrangement which results in a very compact design is the split power transmission. Although the basic gear tooth design of planetary gear configurations is no different from parallel shaft gearing, there are several points that must be considered when rating planetary gears and defining the detail geometry.
