Automatic balancing apparatus

摘要

An automatic balancing apparatus may be mounted in a rotator body such as a spindle motor having a rotary shaft defining an axis of rotation. The automatic balancing apparatus has a plurality of balancing members rotatable about the axis of rotation in a non-contact manner. Each of the balancing members has a balance action section spaced a distance in a radial direction from the axis of rotation and a connection section that rotatably couples the balance action section to the axis of rotation. The balance action section has a mass that effects a balance correction action to cancel a rotational unbalance of the rotator body when the rotator body rotates at a rotational speed that exceeds a resonant rotational speed CR thereof. The connection section has a mass that substantially does not affect the balance correction action compared to the balance action section.