4. Notions on planetary gears

Within the scope of this book, we will not be able to give a detailed study of planetary gear trains. For more details, and in particular for strength calculations, please refer to [1] .

The main advantage of planetary gears is their compact size. Power is distributed over a larger number of gears. The reduced dimensions allow the use of surface-hardening steels with very high strength capacities. Naturally, every effort must be made to balance the loads on the various gears: this is the purpose of the "floating" arrangement of certain components.

Figure 42 gives some examples of assemblies, with the value of the ratio of speeds between extreme...