Spindle motor with arrangement capable of inhibiting half-omega whirl induced during operation

A spindle motor, comprising:

• a bearing system defining a radial orientation;
• a shaft rotatably inserted into the bearing system, the shaft rotating relative to the bearing system during operation of the spindle motor;
• a stator comprising a sleeve adapted to receive the bearing system, the sleeve having an opening;
• and
• a rotor, mounted on the shaft, capable of being driven to rotate together with the shaft relative to the bearing system and the stator during the operation of the spindle motor, the rotor having a bottom surface facing the opening of the sleeve;
• a magnetic apparatus comprising a magnet member mounted on the bottom surface of the rotor and a magnetic permeable member mounted on the opening of the sleeve, the magnet member being used for providing a uniform magnetic field, the magnetic permeable member being affected by the magnetic field, being configured to induce, by the magnetic field, a magnetic force on the shaft toward the radial orientation of the bearing system, so as to inhibit a Half-omega whirl (HOW) of the shaft induced during rotation of the shaft relative to the bearing system.