Patent ID: 6469410
Filing Date: 2002-10-22
Classification: G11B,H02K

Abstract:
An outer rotor disc driving spindle motor in which a rotor having a magnet facing a stator comprising a coil and fixedly supported on a shaft, is located outside of said stator, mounted to a shaft via a first and a second bearings provided with a spacer means inbetween, characterized in that;said rotor is formed a cylindrically showing a drum portion in an axial dimension into which a plural number of discs are laminated in the axial direction and mounted on an outer circumference of said rotor, said rotor rotatably mounted on said shaft via said first bearing positioned in the vicinity of a first opening of said drum portion and said second bearing positioned in a predetermined portion on a side of a second opening, said stator is disposed on a side of said second opening beyond said second bearing and is fixed to a frame which supports said shaft in the vicinity of said second opening, an end surface of said second bearing is set at the same position as a position of the laminate surface position of said discs set in a predetermined position, on the side of the second opening surface, of the outer circumference of said drum portion or closer to the side of the second opening surface, with an outer diameter of said stator set smaller than an outer diameter of said drum portion, said magnet has a magnetic energy product such that a ratio of a distance between said first and second bearings to a length of said shaft set at 0.5 or more, and said spacer means is disposed between outer races of said first and second bearings.