Spindle motor for optical disc drives
First Claim
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.
1 Assignment
0 Petitions
Accused Products
Abstract
A spindle motor for a disc drive, such as a CD-ROM drive, is provided. This spindle motor is a brushless motor of a single-phase axial-winding and radial-gap type including a stator, a rotor coupled to said stator, and a driving circuit for supplying a driving signal to the stator to rotate the rotor. The stator includes a pair of upper and bottom salient-pole pieces formed with a plurality of tooth-like portions serving as salient-poles. The peak surface of each tooth-like portion is formed into a symmetrical convex shape, which minimizes the cogging torque of the motor. Further, the use of a phase-adjuster in the driving circuit allows the motor to produce large output torque at high speeds. The output characteristics of this spindle motor meet the requirements of high speed CD-ROM drives.
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Citations
7 Claims
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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:
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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 including a 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, and a 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 including a 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, and a 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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2. A spindle motor of a single-phase axial-winding and radial-gap type for a disc drive to spin a disc, comprising:
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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; a rotor, coupled to said stator, so as to be rotated by said stator; and a driving circuit, coupled to said stator, for supplying an excitation serving as a driving signal to said stator to rotate said rotor, wherein said driving circuit includes; a Hall sensor, coupled to said rotor, for detecting the speed of said rotor to thereby generate a pulse train whose rate indicates the speed of said rotors, a phase-adjuster, coupled to said Hall sensor, for processing said pulse train to thereby generate a driving signal, a control unit, coupled to said phase-adjuster, for switching the output of said phase-adjuster between a phase-lead driving signal and a phase-lag driving signal, and a bridge-type circuit, coupled to receive the driving signal from said phase-adjuster, for generating an excitation signal to said stator so as to rotate said rotor.
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3. A spindle motor of a single-phase axial-winding and radial-gap type for a disc drive to spin a disc, which comprising:
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a stator; a rotor, coupled to said stator, so as to be rotated by said stator; and a driving circuit, coupled to said stator, for supplying an excitation signal serving as a driving signal to said stator to rotate said rotor; wherein said stator includes; a 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 salientpoles, said upper and bottom salient-pole pieces being interleaved at an electrical angle of 180°
so as to form a doubled number of salientpoles;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 piece, 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; and a circuit board, mounted on said mounting member, for mounting a driving circuit for the spindle motor thereon; and wherein said rotor includes; a 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; and a yoke enclosing said ring-shaped magnet; and wherein said driving circuit includes; a Hall sensor, coupled to said rotor, for detecting the speed of said rotor to thereby generate a pulse train whose rate indicates the speed of said rotor; a phase-adjuster, coupled to said Hall sensor, for processing said pulse train to thereby generate a driving signal; a control unit, coupled to said phase-adjuster, for switching the output of said phase-adjuster between a phase-lead driving signal and a phase-lag driving signal; and a bridge-type circuit, coupled to receive the driving signal from said phase-adjuster, for generating an excitation signal to said stator so as to rotate said rotor.
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4. A spindle motor of a single-phase axial-winding and radial-gap type for a disc drive to spin a disc, comprising:
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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 allowing for a decrease in the cogging torque of said spindle motor; a rotor, coupled to said stator, so as to be rotated by said stator; and a driving circuit, coupled to said stator, for supplying an excitation signal serving as a driving signal to said stator to rotate said rotor, wherein said driving circuit includes; a speed sensor for sensing the speed of said spindle motor to thereby generate a speed signal indicative of the current speed of said spindle motor; and a phase-adjuster, responsive to said speed signal, for adjusting the phase of the driving signal to allow the spindle motor to output optimal torque at high speed. - View Dependent Claims (5, 6, 7)
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Specification