Abstract: The motion and stability conditions of selfsynchronization were studied for a novel noswing vibrating mechanism driven by two motors. The vibrating mechanism comprises an inner rigid frame and an outer rigid frame. The rotational centers of two eccentric rotors are in line with the inner rigid frame center of mass along a vertical axis. Therefore the moment generated by the inertial force of eccentric rotors to the vertical axis is zero， thus eliminating the swing of the vibrating mechanism. The differential motion equations of the vibrating mechanism were established by the Lagrange equation， and the dimensionless coupled motion equation of the eccentric rotors was obtained with the modified average small parameter method. The existence condition of zero solution for the dimensionless coupled motion equation of the eccentric rotors was used to achieve the condition to implement selfsynchronous motion of the vibrating mechanism， and the RouthHurwitz criterion was used to derive the stability conditions of selfsynchronous motion. The numerical simulations verify the correctness of the proposed theories.

Key words: selfsynchronous motion, vibrating mechanism, stability, frequency capture, vibratory synchronization transmission