Abstract: A virtual dynamic balance design method is proposed to solve the problem of dynamic imbalance caused by the geometric structure of non-axisymmetric complex surface revolving parts. Mainly, the whole designed system is simplified to a single rigid body. Then according to the parallel axis theorem, the expression of mass-radius product is obtained. A solution of calculating phase compensation by forward and reverse rotation to phase lag is also proposed. The toroidal worm is taken as an example to be simulated and analyzed on the designed system. After these,the vibration amplitude of the test point in the x-axis direction in the stable period is obtained. The unbalanced masses on two selected test planes are calculated,which are 11.8 g and 14.7 g respectively. By the above solution to phase lag, accurate phase angles corresponding to two unbalanced masses are also obtained, which are 133.2° and 93.6° respectively. After virtual dynamic balancing, the vibration amplitude is decreased by 97.5% and 93% respectively; the effect of balancing is obvious. Eventually, according to the stages of virtual dynamic balancing, the field dynamic balance experiment is carried out. The original unbalanced masses of the worm on the same two selected planes are obtained,which are 13.66 g and 15.21 g respectively. Phase angles corresponding to these two unbalanced masses are also obtained, which are 131° and 95° respectively. Compared with the theoretical value, the maximum error of unbalanced mass is 1.86 g and the maximum error of phase angle is 2.2°. After field dynamic balancing,the residual unbalance masses on the same two planes are obtained,which are 1.33 g and 0.18 g respectively. And the unbalance masses are decreased by 90.3% and 98.8% respectively. The correctness of the proposed theoretical model and virtual dynamic balance method is further demonstrated.

Key words: virtual dynamic balance, non-axisymmetric, complex surface rotating parts, simulation, dynamic balance experiment