Single phase permanent magnet motor and hair dryer using the same

Patent metadata

Field	Value
Publication number	US-10299559-B2
Application number	US-201615246994-A
Country	US
Kind code	B2
Filing date	Aug 25, 2016
Priority date	Aug 28, 2015
Publication date	May 28, 2019
Grant date	May 28, 2019

Abstract

A single phase motor and a hair dryer are provided. The motor includes a stator and a rotor. The stator includes a stator core and a stator winding. The stator core includes an outer ring portion, teeth extending inwardly from the outer ring portion, and two pole shoes extending from a distal end of each tooth. A winding slot is formed between each two adjacent teeth. A slot opening is disposed between the pole shoes of the adjacent teeth, and is offset from one of the two adjacent teeth. The air supplying unit includes the single phase motor and an impeller. The startup angle and cogging torque of the motor are adjustable by adjusting the position/width of the slot opening, without the need of additional positioning slots or positioning holes defined at the pole shoes, which makes the motor structure simple.

First claim

The invention claimed is:

1. A single phase motor comprising
a stator comprising:
a stator core comprising an outer ring portion and a plurality of teeth extending inwardly from the outer ring portion; and
a stator winding wound around the stator core; and

a rotor rotatable relative to the stator, the rotor comprising a plurality of rotor magnetic poles;
wherein each tooth of the stator comprises a tooth body extending inwardly from the outer ring portion and two pole shoes extending respectively from a distal end of the tooth body in two opposite circumferential directions of the rotor and facing the rotor, and the two pole shoes are asymmetrical about a center line of the tooth body such that when the stator winding is not energized the rotor is capable of stopping at an initial position where a center line of each rotor magnetic pole deviates from the center line of a corresponding tooth body.

2. The single phase motor of claim 1 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening or connected together through a magnetic bridge, a center of the slot opening or the magnetic bridge is offset from a symmetrical center of the two adjacent teeth.

3. The single phase motor of claim 1 , wherein inner circumferential surfaces of the pole shoes are coaxial with the rotor such that an air gap with a substantially even thickness is formed between outer circumferential surfaces of the rotor magnetic poles and the inner circumferential surfaces of the pole shoes.

4. The single phase motor of claim 3 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening, and the slot opening has a width less than or equal to four times of the thickness of the air gap.

5. The single phase motor of claim 3 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening, and the slot opening has a minimum width less than or equal to twice of the thickness of the air gap.

6. The single phase motor of claim 1 , wherein each of the two pole shoes has a radial thickness gradually decreasing in a direction away from the tooth body.

7. The single phase motor of claim 1 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening, the two pole shoes of each tooth comprises a shorter pole shoe and a longer pole shoe, and an inner surface of the shorter pole shoe forms a chamfer adjacent the slot opening.

8. The single phase motor of claim 1 , wherein the stator core is formed by joining a plurality of stator core units along a circumferential direction of the stator, each of the stator core units comprises a tooth with a pole shoe and a yoke segment connected to the tooth, and yoke segments of adjacent stator core units are connected together to form the outer ring portion of the stator core.

9. The single phase motor of claim 8 , wherein joining faces of the yoke segments of the adjacent stator core units are plane faces or recess-protrusion engaging faces.

10. The single phase motor of claim 8 , wherein for each of the stator core units, one end of the tooth is connected to one end of the yoke segment or connected to the yoke segment between two ends of the yoke segment.

11. The single phase motor of claim 2 , wherein the center of the slot opening or the magnetic bridge is offset from the symmetrical center of two adjacent teeth by an electric angle ranging from 45 degrees to 135 degrees.

12. The single phase motor of claim 1 , wherein the teeth and the outer ring portion are separately formed and adjacent pole shoes of two adjacent teeth are connected together through a magnetic bridge.

13. The single phase motor of claim 1 , wherein a distance between outer circumferential surface of the rotor magnetic poles and a central axis of the rotor decreases from a central portion of the outer circumferential surface to an end portion of the outer circumferential surface.

14. The single phase motor of claim 13 , wherein the outer circumferential surface of the magnetic pole is symmetrical about a middle radial line of the magnetic pole.

15. A hair dryer comprising an enclosure, a heat generating unit, an air supply unit and a control unit disposed in an interior of the enclosure, the air supply unit comprising a single phase motor and an impeller driven by the single phase motor, the single phase motor comprising:
a stator comprising:
a stator core comprising an outer ring portion and a plurality of teeth extending inwardly from the outer ring portion; and
a stator winding wound around the stator core; and

a rotor rotatable relative to the stator, the rotor comprising a plurality of rotor magnetic poles;
wherein each tooth comprises a tooth body extending inwardly from the outer ring portion, and a large pole shoe and a small pole shoe respectively extending from a distal end of the tooth body in two opposite circumferential directions of the rotor, the pole shoes facing the rotor magnetic poles with an air gap formed there between.

16. The hair dryer of claim 15 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening or connected together through a magnetic bridge, a center of the slot opening or the magnetic bridge is offset from a symmetrical center of the two adjacent teeth such that when the stator winding is not energized the rotor is capable of stopping at an initial position where a center line of each rotor magnetic pole deviates from the center line of a corresponding tooth body.

17. The hair dryer of claim 15 , wherein adjacent pole shoes of two adjacent teeth are separated from each other by a slot opening and an inner surface of the small pole shoe forms a chamfer adjacent the slot opening.

18. The hair dryer of claim 15 , wherein the air supply unit further includes a motor holder and a motor cover, the motor holder has a cylindrical shape having one end formed with an opening, a sidewall of the motor holder is formed with a plurality of first apertures, the single phase motor is fixed in the motor holder, and a power output end of the single phase motor is disposed at a closed end of the motor holder, the motor cover includes one end in a form of a hollow cylinder, and another end of the motor cover is connected to the opening of the motor holder and cooperates with the motor holder to form a Helmholtz resonance cavity, the motor cover is formed with a plurality of second apertures.

19. The hair dryer of claim 15 , wherein the single phase motor is a single phase permanent magnet direct circuit brushless motor.

Assignees

• Johnson Electric Int Ag

Inventors

• Li Yue
• Zhou Chui You
• Chai Jie
• Zhang Tao
• Zhou Qiang

Classifications

• H02K1/14 Primary

  Stator cores with salient poles · CPC title

• H02K21/16 Primary

  having annular armature cores with salient poles (with homopolar co-operation H02K21/20) · CPC title

• H02K1/145

  having an annular coil, e.g. of the claw-pole type · CPC title

• H02K29/03

  with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems · CPC title

• H02K2213/03

  Machines characterised by numerical values, ranges, mathematical expressions or similar information · CPC title