Vibration of Power Transmission Helical Gears : The effect of contact ratio on the vibration

Abstract

On a pair of power transmission helical gears with a comparatively narrow facewidth, the relation between contact ratio and vibration is investigated experimentally for the purpose of decreasing vibration and noise. It has been confirmed that the power transmission helical gears are classified into three categories related to the transverse contact ratio and the overlap ratio as follows. The pair whose overlap ratio is over 1.0 has good vibration characteristics. When the total contact ratio is less than 2.0, the vibration characteristics are similar to those of spur gears. Under the condition that the total contact ratio is over 2.0 and the overlap ratio is less than 1.0, the pair shows a good performance by a modification of tooth profile and trace of the driven gear.