Floppy disk apparatus having an improved disk rotating mechanism

Abstract

A magnetic recording/reproduction apparatus including a motor for rotating a magnetic recording medium such as a floppy disk. The motor has a rotating shaft, a pivot bearing member for supporting the rotating shaft in a thrust direction; a dynamic pressure type radial fluid bearing for rotatably supporting the rotating shaft through a lubricant inside its sleeve, a stator attached to the radial fluid bearing, coils provided on the stator; a rotor fixed to the rotating shaft, and a magnet attached to the rotor. The rotor may have a flange-like engagement portion capable of engaging with a stopper portion formed in a predetermined position to prevent the rotating shaft from coming off the bearing. Preferably, the pivot bearing member is formed of a material having a Vickers hardness of 1200 or higher and is fixed to the sleeve by caulking, the ratio of the diameter of the rotating shaft and the length of the radial fluid bearing in the thrust direction is 1:0.8 to 2, and the diameter of the rotating shaft is not greater than 4.0 mm. The engagement portion at the outer end of the rotor may be constituted by a frequency generator magnet.

Dependencies are inferred from the claim text.