Bearing mechanism for spindle motor in magnetic disk drive

A magnetic disk drive comprising:

• an information storing magnetic disk;
• a spindle motor used for supporting said magnetic disk on a rotating shaft to rotate said magnetic disk;
• a magnetic head for recording or reproducing information on said magnetic disk;
• a pivot hub for supporting said magnetic head through a suspension;
• a rotational center shaft serving as the rotational center of said pivot hub;
• and
• a ball bearing provided between said rotational center shaft and said pivot hub and provided with a mechanism to make balls in the ball bearing hard to rotate in a specific direction,
• wherein said ball bearings are provided on both ends of said rotational center shaft, and the direction in which said balls are hard to rotate is opposite for both ends of said rotational center shaft.

A magnetic disk drive comprising:

• an information storing magnetic disk;
• a rotating shaft for supporting said magnetic disk;
• a fixed shaft serving as the rotational center of said rotating shaft;
• a ball bearing provided between said fixed shaft and said rotating shaft and provided with a mechanism to make balls hard to rotate in a specific direction;
• and
• a magnetic head for recording or reproducing information on said magnetic disk,
• wherein said ball bearing has a holder that limits spaces defined by said ball, and said mechanism to make balls hard to rotate in a specific direction is provided on said holder, said mechanism being a bush having a plurality of spring plates to come into contact with said balls.