Patent ID: 6188152
Filing Date: 2001-02-13
Classification: G11B,H02K

Abstract:
A motor having a magnet provided on a rotor rotatably supported on a fixed shaft by a rotary sleeve via a fluid bearing and a stator winding mounted to a stator core facing said magnet, said motor for rotationally driving a disk-shaped recording medium placed on said rotor around the shaft axis whereinthe diameter of said fixed shaft is d (mm) which is within a maximum diameter and a minimum diameter, the service number of revolutions is N (rpm), the number of said disk-shaped recording media is k, and the diameter of said disk-shaped recording medium is D (inch), and the following relation is satisfied:.alpha..sup.3.multidot.M1>d.sup.3 >M1where M1=J1.multidot.(N/1000).sup.2.multidot.k.sup.2.multidot.D, J1being a coefficient between 0.018.+-.20%, and .alpha. equaling a ratio of the maximum diameter to the minimum diameter of said fixed shaft.