Rotary drive apparatus

A rotary drive apparatus comprising:

• a stationary portion including a stator;
• and
• a rotating portion supported through a bearing portion to be rotatable about a central axis extending in a vertical direction with respect to the stationary portion, the rotating portion including a magnet arranged opposite to the stator;
• wherein
• the rotating portion includes:
• a shaft arranged to extend along the central axis;
• a first rotor hub portion arranged to extend in an annular shape around the shaft;
• a second rotor hub portion arranged below the first rotor hub portion, and arranged to extend in an annular shape around the shaft;
• a first inertia portion directly or indirectly fixed to the first rotor hub portion, and having a specific gravity greater than that of the first rotor hub portion;
• and
• a second inertia portion directly or indirectly fixed to the second rotor hub portion, and having a specific gravity greater than that of the second rotor hub portion;
• the stationary portion includes:
• a sleeve portion arranged to rotatably support the shaft;
• and
• a base portion arranged to directly or indirectly support the sleeve portion;
• the first inertia portion is arranged above the base portion;
• the second inertia portion is arranged below the base portion;
• the bearing portion includes:
• an upper bearing portion;
• and
• a lower bearing portion arranged below the upper bearing portion;
• and
• a center of gravity of the rotating portion is located below an upper end of the upper bearing portion and above a lower end of the lower bearing portion.