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US 5,532,531 AGranted
Permanent magnet type brushless motor
AssigneeJapan Servo Co., Ltd.
InventorMasafumi Sakamoto
Life of this patent
Estimating the term…
Abstract
A permanent magnet type brushless motor wherein the number of a stator magnetic poles is 3 m (where m is an integer not less than 2), Z pieces of N pole and Z pieces of S pole (where Z is m (3n.+-.1), and n is an integer not less than 2) are magnetized alternately with the same pitch, and an angle formed between a center of N pole of the permanent magnet corresponding to a pole tooth at the center of any one of the stator magnetic poles and a center of S pole of the permanent magnet corresponding to a pole tooth at the center of one of the stator magnetic poles adjacent to the any one of the stator magnetic poles is 360.degree. (n.+-.1/2)/Z.
Claims11
A permanent magnet type brushless motor comprising
- a cylindrical stator,
- 3 m pieces of stator magnetic pole extending inwardly in the radial direction from the inner peripheral surface of said stator, m being an integer not less than 2, and each of said stator magnetic poles having a plurality of pole teeth on the tip thereof,
- stator exciting windings each wound around on each of the stator magnetic poles,
- a cylindrical permanent magnet facing the inner peripheral surfaces of said pole teeth of the stator magnetic poles with a gap therebetween, said permanent magnet having
- Z pieces of N pole and Z pieces of S pole magnetized alternately around the circumference thereof with the same pitch, where Z=m(3n.+-.1), and n is an integer not less than 2, and
- an angle formed between
- the center of an N pole of said permanent magnet, said N pole corresponding to a first pole tooth, said first pole tooth being at the center of a first one of said stator magnetic poles, and
- the center of an S pole of said permanent magnet, said S pole corresponding to a second pole tooth, the second pole tooth being at the center of a second one of said stator magnetic poles, said second one of said stator magnetic poles being adjacent to said first one of said stator magnetic poles,
- such that magnetic flux from said N pole of said permanent magnet is passed through said first one of said stator magnetic poles and returned to said S pole through said second one of said stator magnetic poles, said magnetic flux having a radial orientation as it passes through said N pole and said S pole of said permanent magnet,
- and such that the radial orientation of said magnetic flux through said stator magnetic poles alternates with each successive stator magnetic pole,
- a back yoke of magnetic material intimately attached on the inner peripheral surface of said permanent magnet, and
- a rotary shaft for supporting said back yoke.
9 more elements
A permanent magnet type brushless motor comprising
- a planar stator,
- 3m pieces of stator magnetic pole extending outwardly in the radial direction on said stator, m being an integer, and each of said stator magnetic poles having at one side surface thereof a plurality of pole teeth projected axially,
- stator exciting windings each wound around on each of the stator magnetic poles,
- an annular permanent magnet, one side surface of which is faced to side surfaces of said pole teeth of the stator magnetic poles with a gap therebetween, said permanent magnet having
- Z pieces of N pole and Z pieces of S pole magnetized alternately around the circumference thereof with the same pitch, where Z=(3n.+-.1), and n is an integer not less than 2, and
- an angle formed between
- the center of an N pole of said permanent magnet, said N pole corresponding to a first pole tooth, said first pole tooth being at the center of a first one of said stator magnetic poles, and
- the center of an S pole of said permanent magnet, said S pole corresponding to a second pole tooth, said second pole tooth being at the center of a second one of said stator magnetic poles, said second one of said stator magnetic poles being adjacent to said first one of said stator magnetic poles,
- such that magnetic flux from said N pole of said permanent magnet is passed through said stator magnetic pole corresponding to said N pole and returned to said S pole through said one of stator magnetic poles adjacent to said any one of the stator magnetic pole, said magnetic flux having a radial orientation as it passes through said N pole and said S pole of said permanent magnet,
- and such that the radial orientation of said magnetic flux through said stator magnetic poles alternates with each successive stator magnetic pole,
- a back yoke of magnetic material intimately attached on the other surface of said permanent magnet, and
- a rotary shaft for supporting said back yoke.
9 more elements
A permanent magnet type brushless motor comprising
- a cylindrical stator,
- 3 m pieces of stator magnetic pole extending outwardly in the radial direction from the outer peripheral surface of said stator, m being an integer not less than 2, and each of said stator magnetic poles having a plurality of pole teeth on the tip thereof, two of said stator magnetic poles being connected back to back with each other to form a stator leg,
- stator exciting windings each wound around on each of the stator legs,
- a cylindrical permanent magnet facing the outer peripheral surface of said pole teeth of the stator magnetic poles with a gap therebetween, said permanent magnet having
- Z pieces of N pole and Z pieces of S pole magnetized alternately around the circumference thereof with the same pitch, where Z=m(3n.+-.1), and n is an integer not less than 2, and
- an angle formed between
- the center of an N pole of said permanent magnet, said N pole corresponding to a first pole tooth, said first pole tooth being at the center of a first one of said stator magnetic poles, and
- the center of an S pole of said permanent magnet, said S pole corresponding to a second pole tooth, said second pole tooth being at the center of a second one of said stator magnetic poles, said second one of said stator magnetic poles being adjacent to said first one of said stator magnetic poles,
- such that magnetic flux from said N pole of said permanent magnet is passed through said stator magnetic pole corresponding to said N pole and returned to said S pole through said one of the stator magnetic poles adjacent to said any one of the stator magnetic poles, said magnetic flux having a radial orientation as it passes through said N pole and said S pole of said permanent magnet,
- and such that the radial orientation of said magnetic flux through said stator magnetic poles alternates with each successive stator magnetic pole,
- a back yoke of magnetic material intimately attached on the outer peripheral surface of said permanent magnet, and
- a rotary shaft for supporting said back yoke.
9 more elements
Dependencies are inferred from the claim text.