Spindle motor for driving storage disc of hard disk drive, has pressure balancing unit for balancing pressure in bearing gap, and channel provided in axial direction at inside diameter of pressure plate in connecting region with shaft

摘要

The motor (10) has a bearing component held in a base plate (12) and provided with a bearing unit. Another bearing component is provided with a bearing unit, and includes a hub (22). The latter component is separated from the former component by a bearing gap (20), and is rotatably driven around a common rotation axis (24) together with the hub by an electromagnetic drive system. A pressure balancing unit is provided for balancing pressure in the gap. A recirculation channel is provided in an axial direction at inside diameter of a pressure plate in a connecting region with a rotary shaft.