Vibration of Three Axes Gear System

To reveal basic dynamic features of a gearbox for four-wheel-drive automobile, a test gearing unit having a countershaft was manufactured. Gears can be placed at arbitrary positions on the shafts, and fixed with any phase shift between two meshing pairs. Through the vibration measurement of gears, it has become clear that the effect of countershaft on vibration depends upon both spacing and phase difference between the two pairs. And a resonant state with tooth separation is evident. These features agree well with simulated results which take the effect of the shaft into consideration. It has also become clear that the sound radiation is especially related to the bending vibration of the countershaft.