Investigation of Tooth Precision on Meshing Noise of Planetary Gear Train: Combinations of Different Tooth Precisions and Sound Intensity

Noise is one of major serious issues for planetary gear trains (PGTs). It is called noise hazard in serious cases such as cabin in a helicopter where the sound level reaches 100dB. In this paper, several precisions of planet gears are combined to investigate the influence of tooth precision on meshing noise of PGTs. The meshing noise of PGTs is generated by stiffness coefficient excitation and error excitation forces, but stiffness coefficient excitation is assume to be constant in this paper because slight error on the tooth surface doesn't effect on meshing stiffness. It was found that maintaining the same precision for all planet gears is the best; if one of the planet gears has a precision far from the others, the sound pressure level increases. The deviation for the maximum error among all meshing pairs, should be restricted to no more than 3μm in case of module one spur gear.