Abstract
This paper shows the simulated results of the resonance which occurs in star-type planetary gear trains. In this simulation, the inner gear and the planetary gear have the installation error and the eccentricity to the rotating center. The inner gear has a manufacturing error at pitch circle shape as well. The influences of the errors to the resonance are discussed. As the summary, the installation error of the inner gear and the planetary gear are not the cause of the resonance of the gear trains. The eccentricity of the inner gear is not a cause of the resonance but the eccentricity of the planetary gear is the cause of the resonance, but this error excites another higher vibration mode. The cause of the present resonance can be thought that the inner gear, whose shape is triangle, installed on the planetary gear trains, which has tree planetary gears.
