On the Three-Dimentional Motion of Ball in Ball Bearing

A magnetized ball rolling in a ball bearing induces an alternating current in the coil wound on the outer race. The period of the current shows one revolution of the ball. The slip of the ball is found by measuring the deviation of the period from the theoretical value. The variation of the axis of rotation relative to the magnetic axis of the ball is easily estimated from the variation of the amplitude of the current. Under the radial load an appreciable amount of the slip occurs at the unloaded side. It decreases exponentially with an increase in shaft speed. The variation of the axis of rotation is quite regular and is closely related to the slip. The cause of the variation is supposed to be due to the skewing motion of the ball at the moment of the slip.