The natural frequency and mode shape when involute helical gear under the axisymmetric transverse bending vibration of zero pitch diameter is the best for the vibration system of ultrasonic.A three-dimensional finite element model of helical gearisbuiltthroughAPDLfirstly

thenmodal analysisof helical gearis conducted.The helical gear first-order frequency are extracted in a parametric way byVB and APDL

the resonantfrequency of finiteelement analysis is in accordance with the resonant frequency of experiment.