Efficiency analysis of planetary gears

Abstract

By kinematic combinations of toothed pairs with external and internal contacts, we can obtain planetary gears with a considerably improved performance than the corresponding ones with fixed axes, as well as planetary gears with notably poor performance regarding the efficiency. In regard to that, the reference literature and papers almost regularly emphasize that planetary gears, under the same technical conditions, have a smaller mass and a higher degree of efficiency than the ones with fixed axes. The main aim of this paper is to examine the above statement and to determine the scope of the gear ratios in which the planetary gears are more suitable than the fixed axes gears.