Multi-phase hybrid stepper motor

• US 5,374,865 A
• Filed: 07/30/1993
• Issued: 12/20/1994
• Est. Priority Date: 07/31/1992
• Status: Expired due to Term

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Yoshida, Kenji, Yoshimura, Noriyuki
• Primary Examiner(s): Stephan, Steven L.
• Assistant Examiner(s): JONES, JUDSON
• Application Number:
  US08/099,539
• Time in Patent Office: 508 Days
• Field of Search: 310/49 R, 318/696
• US Class Current: 310/49.24
• CPC Class Codes: H02K 37/18 of homopolar type

Abstract

To minimize fluctuation of torque, improve torque stiffness, and reduce resonance vibration during rotation in the hybrid stepper motor.

The magnetic poles have two or more teeth placed with the same spaces as with toothpitch of the rotor. The total number (NS) of the teeth of the nonsymmetrical stators is determined by NS=5×(n0 +nl), where n0 is the number of teeth of each of five poles and nl is the number of teeth of each of remaining five poles. The nonsymmetrical stator, of which the teeth are nl, is placed between the nonsymmetrical stators, of which the teeth are n0, so that the nonsymmetrical stator, of which the teeth are n0, is placed on the opposite side of the nonsymmetrical stator, of which the teeth are n1, when the core of the rotation axis is the center. The total number (NS) of the teeth (NR) of the rotor and the teeth of the stators corresponds to the relationship of NS≧0.8 NR (NS is equal to or greater than 0.8 NR), and the difference between NR and NS is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is an integer between 2 and 5, S0 and S1 are integers as small as possible in such a way that S1 can also be equal to S0, B is a fraction of 1, 10B is an integer. The ten windings produce as many north-and south-poles as necessary by using a power supply method to supply applied power to achieve full step angles =electrical angle 90°=αF, αF=360°/10 NR and half step angle=electrical angle 45°=αH, αH =360°/20NR.

Claims

1. A multi-phase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the statorpoles having one untapped winding;

the statorpoles having two or more teeth spaces with the toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1, teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth NS of NS≧

0.8 NR (equal or greater than) and with a difference between NR and NS which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integers as small as possible in such a way that S1 can also be equal to S0 and where B is a fraction of one (1) in such a way that 10B (10 times B) is always an integer; and

a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that said 10 windings form as many north-and south-poles necessary to achieve full stepangles=electrical angle 90=α

F, α

F=360 s/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR.

2. A stepper motor according to claim 1, wherein the 10 pole windings are connected in such a way to torm a dectagon with 10 connecting points of which every point can be individually connected through electronic switches with a voltage source, or current source north-and south-poles such that at least two adjacent poles are south.

3. A multi-phase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one uptapped winding;

the poles having two or more teeth spaced with the toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator NS of NS≧

0.8 NR (equal or greater than) and with a difference between NR and NS which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integers as small as possible in such a way that S1 can also be equal to S0 and where B has a value of 0.3 (B=0.3) and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangles=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 36 will be achieved between poles 1 and 8, between poles 2 and 9, between poles 3 and 10, and so on, counted in one direction.

4. A stepper motor according to claim 3, wherein the pole windings of two (2) opposite poles get energized in such a way that the poles have opposite polarity (north and south).

5. A stepper motor according to claim 3, wherein the constants K, S0, S1, are chosen in such a way that the stator has 10 teeth less than the number of rotor teeth NR;

(NS=NR-10).

6. A multi-phase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its peripherya number of NR evenly spaced, radially outward directed teeth;

the rotorpolecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360 NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with said toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth NS of NS≧

0.8 NR (Equal or greater than) and with a difference between NR and NS which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, and S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and where B has a value of 0.7, (B=0.7) and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrocal angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 36 will be achieved between every fourth pole, as an example between poles 1 and 4, between poles 2 and 5, and so on, counted in one direction.

7. A stepper motor according to claim 6, wherein the pole windings of two (2) opposite poles get energized in such a way that the poles have oppoosite polarity (north and south).

8. A stepper motor according to claim 6, wherein the constants K, S0, S1 are chosen in such a way that the stator has 10 teeth less than the number of rotor teeth NR;

(NS=NR-10).

9. A multi-phase hybrid stepper motor comprising of a rotor system with at least one exially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenlyspaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with the toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth Ns≧

0.8 NR (equal or greater than) and with a difference between NR and N5 which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integervarying from 2 to 5, S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.2, (B=0.2), and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90 =α

F, α

F=360/10 NR and half stepangle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 72 will be achieved between every two adjacent poles.

10. A stepper motor according to claim 9, wherein the pole windings of two (2) opposite poles get energized in such a way that the poles have the same polarity (north and south).

11. A multi-phase hybrid stepper motor comprising of a rotor system with at least one exially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with said toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth Ns of Ns≧

0.8 NR (equal or greater than) and with a difference between NR and N5 which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.3, (B=0.3), and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 36 will be achieved between poles 1 and 8, between poles 2 and 9, between poles 3 and 10, and so on, counted in one direction, and the constants K S0, are chosen in such a way that the stator has 3 teeth less than the number of rotor teeth NR;

(NS=NR-3).

12. A stepper motor according to claim 11, wherein every second of the ten poles has one more tooth in such a way that 5 poles have a number of teeth n0, and their adjacent poles have a number of teeth n1.

13. A multi-phase hybrid steper motor comprising of a rotor system with at least one exially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with said toothpitch Tp, a total number of stator teeth NS coresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relatinship between the number of rotor teeth NR and the total number of the stator teeth Ns of NS≧

0.8 NR(equal or greater than) and with a difference between NR and N5 which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.3, (B=0.3), and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle 36 will be achieved between poles 1 and 8, between poles 2 and 9, between poles 3 and 10, and so on, counted in one direction, and the constants K, S0, S1 are chosen in such a way that the stator has 5 teeth less than the number of rotor teeth NR;

(NS=NR-5).

14. A stepper motor according to claim 13, wherein every second of the ten poles has one more tooth in such a way that 5 poles have a number of teeth of teeth n0, and their adjacent poles have a number of teeth n1.

15. A multi-phase hyrid stepper motor comprising of rotor system with at least one exially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with said toothpitch Tp, a total number of stator teeth NS coresponding to the relation of NS=5(n0+n1) with n0 being the numer of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth Nr and the total number of the stator teeth Ns≧

0.8 NR(equal or greater than) and with a difference between NR and N5 which is defined by the equation NR-NS=K(S0-S1)+10(S1-1 +B), where K is any integer varying from 2 to 5, S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.3, (B=0.3), and a winding scheme in such a way that the 10 windings can be enrgized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 36 will be achieved between poles 1 and 8, between poles 2 and 9, between poles 3 and 10, and so on, counted in one direction, and the constants K, S0, S1 are chosen in such a way that the stator has 15 teeth less than the number of rotor teeth NR;

(NS=NR-15).

16. A stepper motor according to claim 15, wherein every second of the ten poles has one more tooth in such a way that 5 poles have a number of teeth N1.

17. A multi-phase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/4) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with the toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+n1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth Ns of Ns≧

0.8 NR (equal or greater than) and with a difference between NR and N5 which is defined by the equation NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, SO and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.7, (B =0.7), and a winding scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 36 will be achieved between every fourth pole, as an example between poles 1 and 4, between poles 2 and 5, and so on, counted in one direction, and the constants K, S0, S1 are chosen in such a way that the stator has 7 teeth less than the number of rotor teeth NR;

(NS=NR-7).

18. A stepper motor according to claim 17, wherein every second of the ten poles has one more tooth in such a way that 5 poles have a number of teeth n0, and their adjacent poles have a number of teeth n1.

19. A multiphase hybrid stepper motor comprising of a rotor system with at least one axially magnetized permanent magnet, having one polecap on each side;

the polecap made of soft magnetic iron having on its periphery a number of NR evenly spaced, radially outward directed teeth;

the rotor polecaps on each side are offset in rotational direction to each other by one half (1/2) toothpitch Tp=360/NR, a nonsymmetrical stator surrounding the rotor and having ten (10) radially inwardly directed statorpoles, each of the poles having one untapped winding;

the poles having two or more teeth spaced with said toothpitch Tp, a total number of stator teeth NS corresponding to the relation of NS=5(n0+N1) with n0 being the number of teeth of each of 5 poles and n1 the number of teeth of each of remaining 5 poles, each one of the poles in between of the 5 poles with n0 teeth placed in such a way that opposite of each of the poles n0 teeth is one pole with n1 teeth, a relationship between the number of rotor teeth NR and the total number of the stator teeth Ns of Ns≧

0.8 NR (equal or greater than) and with a difference between NR and N5 which is defined by the euation. NR-NS=K(S0-S1)+10(S1-1+B), where K is any integer varying from 2 to 5, S0 and S1 are integer as small as possible in such a way that S1 can also be equal to S0 and B has a value of 0.2, (B=0.2), and a windings scheme in such a way that the 10 windings can be energized through a voltage source or current source so that the 10 windings form as many north-and south-poles necessary to achieve full stepangle=electrical angle 90=α

F, α

F=360/10 NR and half stepangle=electrical angle 45=α

H, α

H=360/20 NR, and an electrical shiftangle of 72 will be achieved between every two adjacent poles, and the constants K, S0, S1 are chosen in such a way that the stator has 5 teeth less than the number of rotor teeth NR;

(NS=NR-5).

20. A stepper motor according to claim 19, wherein every second of the ten poles has one more tooth in such a way that 5 poles have a number of teeth n0, and their adjacent poles have a number of teeth n1.