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US 6,191,509 B1Granted
Permanent magnet type stepping motor
AssigneeSanyo Denki Co., Ltd.
InventorsTsunao Yura, Akira Koike
Life of this patent
Estimating the term…
Abstract
A permanent magnet type stepping motor capable of exhibiting increased rotational angle accuracy and static angle accuracy. Claw pole type yoke units each include two yokes each provided with n (n: a positive integer of 4 or more) pole teeth. One of the yokes includes n/m pole teeth arranged in each of angular ranges of 360° /m (m: a divisor of n other than 1 and n). Pitches a between pole teeth positioned in each angular range are set to be within a range of (90° /n) [4−m/(n−m)] <a<(360° /n). A pitch b between two pole teeth positioned on both side of a boundary between each adjacent two angular ranges is set to be within a range of (360° /n)<b<(450° /n). The other yoke has pole teeth arranged between the pole teeth of the one yoke.
Claims19
A permanent magnet type stepping motor comprising:
- a rotor having a permanent magnet element fixed on a revolving shaft;
- said permanent magnet element being constructed into a cylindrical configuration so as to permit n (n:
- a positive integer of 4 or more) north (N) magnetic poles and n south (S) magnetic poles to alternately appear at equal pitches thereon in a circumferential direction of said revolving shaft;
- and
- a stator including two or more claw pole type yoke units juxtaposed to each other in an axial direction of said revolving shaft;
- said claw pole type yoke units each including first and second yokes and an exciting winding;
- said first and second yokes each including n pole teeth arranged opposite to said permanent magnet element at a predetermined interval in a radial direction of said revolving shaft and positioned at predetermined pitches in said circumferential direction;
- said exciting winding being constructed so as to permit said n pole teeth of said first yoke and said n pole teeth of said second yoke to be excited at polarities different from each other;
- said first and second yokes being combined with each other so that said n pole teeth of said first yoke and said n pole teeth of said second yoke are engaged with each other while being kept from being contacted with each other;
- said n pole teeth of said first yoke of each of said claw pole type yoke units being so arranged that mechanical pitches between respective adjacent two of said n pole teeth of said first yoke are not set to be constant at 360° /n but set at two or more different pitches which are larger than 270° /n and smaller than 450° /n;
- said n pole teeth of said second yoke of each of said claw pole type yoke units being so arranged that a pitch between each adjacent two of said n pole teeth of said second yoke is set so as to permit said n pole teeth of said first yoke and said n pole teeth of said second yoke to be engaged with each other while being kept from being contacted with each other.
8 more elements
A permanent magnet type stepping motor comprising:
- a rotor having a permanent magnet element fixed on a revolving shaft;
- said permanent magnet element being constructed into a cylindrical configuration so as to permit n (n:
- a positive integer of 4 or more) north (N) magnetic poles and n south (S) magnetic poles to alternately appear at equal pitches thereon in a circumferential direction of said revolving shaft;
- and
- a stator including two or more claw pole type yoke units juxtaposed to each other in an axial direction of said revolving shaft;
- said claw pole type yoke units each including first and second yokes and an exciting winding;
- said first and second yokes each including n pole teeth arranged opposite to said permanent magnet element at a predetermined interval in a radial direction of said revolving shaft and positioned at predetermined pitches in said circumferential direction;
- said exciting winding being constructed so as to permit said n pole teeth of said first yoke and said n pole teeth of said second yoke to be excited at polarities different from each other;
- said first and second yokes being combined with each other so that said n pole teeth of said first yoke and said n pole teeth of said second yoke are engaged with each other while being kept from being contacted with each other;
- said first yoke of each of said claw pole type yoke units including said pole teeth of n/m (m:
- a divisor of n other than 1 and n) in number in each of angular ranges of 360° /m;
- said n/m pole teeth positioned in each of said angular ranges being arranged at mechanical pitches (a) set to be within a range of (90° /n) [4−m/(n−m)] <a<(360° /n);
- two said pole teeth positioned on both sides of a boundary between each adjacent two of said angular ranges being arranged at a mechanical pitch (b) set to be within a range of (360° /n)<b<(450° /n).
10 more elements
A permanent magnet type stepping motor comprising:
- a rotor having a permanent magnet element fixed on a revolving shaft;
- said permanent magnet element being constructed into a cylindrical configuration so as to permit n (n:
- a positive integer of 4 or more) north (N) magnetic poles and n south (S) magnetic poles to alternately appear at equal pitches thereon in a circumferential direction of said revolving shaft;
- and
- a stator including two or more claw pole type yoke units juxtaposed to each other in an axial direction of said revolving shaft;
- said claw pole type yoke units each including first and second yokes and an exciting winding;
- said first and second yokes each including n pole teeth arranged opposite to said permanent magnet element at a predetermined interval in a radial direction of said revolving shaft and positioned at predetermined pitches in said circumferential direction;
- said exciting winding being constructed so as to permit said n pole teeth of said first yoke and said n pole teeth of said second yoke to be excited at polarities different from each other;
- said first and second yokes being combined with each other so that said n pole teeth of said first yoke and said n pole teeth of said second yoke are engaged with each other while being kept from being contacted with each other;
- said first yoke of each of said claw pole type yoke units including said pole teeth of n/m (m:
- a divisor of n other than 1 and n) in number in each of angular ranges of 360° /m;
- said n/m pole teeth positioned in each of said angular ranges being arranged at mechanical pitches (a) set to be within a range of (90° /n) [4+m/(n−m)] >a>(360° /n);
- two said pole teeth positioned on both sides of a boundary between each adjacent two of said angular ranges being arranged at a mechanical pitch (b) set to be within a range of (360° /n)>b>(270° /n).
10 more elements
Dependencies are inferred from the claim text.