Abstract
A ball balancer is a balancing device where two balls inside a hollow rotor locate automatically to eliminate vibrations in the rotational speed range higher than the major critical speed. However, it has following defects. First, the amplitude of vibration increases in the lower rotational speed range. Next, almost periodic motions with large amplitude occur due to the rolling of balls inside rotor in the higher side of the major critical speed. Due to those defects, the automatic ball balancer have not been used widely. In this paper, we propose to use the vibration suppression method utilizing discontinuous spring characteristics together with a dynamic ball balancer to overcome these defects. The validity of proposed method is confirmed theoretically, numerically and experimentally. The results show that amplitude of vibration can be suppressed to a small amplitude in the vicinity of the major critical speed and the zero amplitude in the higher rotational speed side.
