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Spindle motor for optical disc drives

  • US 5,923,110 A
  • Filed: 03/31/1997
  • Issued: 07/13/1999
  • Est. Priority Date: 03/17/1997
  • Status: Expired due to Fees
First Claim
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1. A spindle motor of a single-phase axial-winding and radial-gap type for a disc drive to spin a disc, comprising:

  • a stator having a plurality of tooth-like portions serving as salientpoles, each tooth-like portion having a peak surface formed into a symmetrical convex shape, the symmetrical convex shape of said tooth-like portions of said stator allowing for a decrease in the cogging torque of said spindle motor, said stator further includinga pair of salient-pole pieces including an upper salient-pole piece and a bottom salient-pole piece, each being formed by a stack of silicon steel having a plurality of tooth-like portions serving as a plurality of poles, said upper and bottom salient-pole pieces being interleaved at an electrical angle of 180°

    so as to form a doubled number of salient-poles,a flux-guiding ring, coupled between said upper and bottom salient-pole pieces, for providing a flux path between said upper and bottom salient-pole pieces,a bobbin which fits over said flux-guiding ring,a coil, wound around said bobbin, for excitation of the salientpoles formed on the upper and bottom salient-pole pieces,a flux-guiding sleeve for axially coupling said bottom salient-pole pieces, said flux-guiding ring, and said upper salient-pole piece thereon, said flux-guiding sleeve being made of a magnetic material having a bore and a supporting flange for supporting said bottom salient-pole piece when said bottom salient-pole piece is axially coupled on said flux-guiding sleeve,a plurality of bearings coupled axially in the bore of said flux-guiding sleeve,a mounting member made of a non-magnetic material and coupled securely to said flux-guiding sleeve by means of fastening to the coupling mouth on said flux-guiding sleeve, anda circuit board, mounted on said mounting member, for mounting a driving circuit for the spindle motor thereon;

    a rotor, coupled to said stator, so as to be rotated by said stator, said rotor includinga turntable for positioning the disc thereon,a spindle for turning said turntable, said spindle having a circular slot formed near the bottom end thereof,a ring-shaped magnet coupled axially to said spindle and said upper and bottom salient-pole pieces on said stator, anda yoke enclosing said ring-shaped magnet;

    a frictional piece for supporting said spindle when said rotor is coupled to said stator;

    a stopper for supporting said frictional piece;

    a spindle locking ring for insetting in said circular slot formed on said spindle so as to lock said spindle in position when said rotor is coupled to said stator; and

    a stopper locking ring for locking said stopper in position.

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