The invention relates to the spindle motor for driving a hard disk drive, comprising: a stationary motor component (10, 12, 16, 18), a rotary motor component (14) rotatably mounted relative to the stationary motor component using a fluid dynamic bearing system, a bearing gap (20) disposed between the stationary motor component and the rotary motor component and filled with a bearing fluid, having at least one open end, at least one sealing gap (34) for sealing the open end, at least one cover cap (30) for covering the sealing gap, which is secured to the rotatable motor component, a disk clamp (44) for attachment of at least one magnetic storage disk (48) on the rotatable motor member and an electromagnetic drive system (40, 42) to drive the rotatable motor member. The disk clamp (44, 156) is centered on a peripheral surface of the cover cap (30, 118).