On the Subharmonic Vibration of the Order One-half Caused by Passing Balls in a Ball Bearing

抄録

The authors analyzed the axial motion of a horizontal rotor supported by a ball bearing and a journal bearing. The results of analysis show that the ball bearing possesses a spring constant varying with the motion of the balls. So in some regions the motion becomes unstable and a subharmonic vibration of the order one-half may appear. Statical experiments in order to determine the stiffness of the ball bearing and dynamical experiments to measure the subharmonic vibrations of the order one-half have been carried out for two ball bearings having respectively three and six balls. The unstable regions where a subharmonic vibration appeared agreed with the analytical results. At the boundaries between the stable and the unstable regions, the subharmonic vibration and the forced vibration caused by the inclination of the groove of the inner ring composed a beat. The period and the phase of the beat agreed with the analytical results.