ABSTRACT
This chapter presents the basic directions in which the optimization of planetary gear trains is performed, and things are given as a prescription, as it is preferred by engineers. The external meshing between the sun gear and the planets is most often the weaker one compared to the internal meshing between the planets and the ring gear. More special case is when the sun gear is closer to one of the bearings. Besides the two predominant gear damages—fracture and pitting, there is another damage characteristic of low-speed heavy-loaded gears. This is the wear of the teeth due to the inability to form a load-bearing oil film due to the low speed and high load. An important factor in the fight for noise reduction is the determination of the modal frequency of gear train as a whole, taking into account its attachment to the seating.
