| 摘要 |
PURPOSE:To reduce the frictional resistivity acting on an addition weight as well as to aim at the miniaturization of a driving actuator and an increase in the service life of a bearing assembly, by applying a noncontact magnetic supporting device, which uses electromagnetic force, to the bearing assembly supporting the addition weight. CONSTITUTION:A supporting shaft 22 of an addition weight 21 is magnetically attracted and supported by an electromagnet 5 composed of an iron core 51 and an exciting coil 52. An exciting current of the exciting coil 52 is controlled by a positional signal out of a position detector 6 detecting a level position of the supporting shaft 22, while the supporting shaft 22 is supported together with a supporting block 23 each other in a noncontact manner. As a result, frictional resistivity against motion in a horizontal direction of the addition weight 21 is nil, therefore vibrations are very smooth indeed, thus not only the driving force required for an actuator 25 is reduced in its capacity but also service life for a supporting mechanism of the addition weight 21 is prolonged. |
