Fluid generating device and electric apparatus using the same
A fluid generating device and an electric apparatus utilizing the fluid generating device are provided. The fluid generating device includes a motor and an impeller driven by the motor. The motor is a single phase direct current brushless motor which 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, a pole shoe formed at the tooth. Slot openings are formed between the pole shoes. The rotor is received in a receiving chamber defined by the pole shoes. Inner surfaces of the pole shoes and the rotor form therebetween a substantially even air gap. The presence of even air gap can reduce the cogging torque of the motor, thus reducing the startup current and noise of the motor.
1. A fluid generating device comprising:
a single phase motor comprising:
a stator comprising a stator core and a stator winding wound around the stator core, the stator core comprising a yoke, a plurality of teeth extending inwardly from the yoke, a pole face formed at a distal end of each of the teeth and extending along a circumferential direction of the motor;
a rotor rotatable relative to the stator, the rotor being received in a receiving chamber surrounded by the pole faces, the rotor comprising a plurality of magnetic poles confronting the pole faces of the stator, outer surfaces of the magnetic poles of the rotor and the pole faces of the stator being coaxial with each other to thereby form there between a substantially even air gap; and
an impeller being driven by the rotor to generate a fluid flow;
wherein circumferential ends of each pole face form a left cutting surface and a right cutting surface, the right cutting surface of one tooth and the left cutting surface of adjacent teeth form a slot opening, a distance between the left cutting surface and the right cutting surface forming the slot opening is 0.09 to 0.13 times an outer diameter of the rotor.
2. The fluid generating device of claim 1 , wherein each tooth comprises a tooth body extending from the yoke and a pair of pole shoes extending respectively from a distal end of the tooth body in two opposite circumferential directions of the rotor.
3. The fluid generating device of claim 2 , wherein the pole shoe has a radial thickness gradually decreasing in a direction away from the tooth body.
4. The fluid generating device of claim 2 , wherein the slot opening is offset from a symmetrical center between the two adjacent teeth bodies.
5. The fluid generating device of claim 4 , wherein the two pole shoes comprise a shorter pole shoe and a longer pole shoe, and only the inner surface of the shorter pole shoe forms a chamfer adjacent the slot opening.
6. The fluid generating device of claim 4 , wherein the slot opening is offset from a symmetrical center of corresponding two adjacent teeth by an electric angle of 45 to 135 degrees.
7. The fluid generating device 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 its pole shoe, and a yoke segment connected to the tooth, and the yoke segments of the adjacent stator core units are connected together to form the yoke of the stator core.
8. The fluid generating device of claim 7 , 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.
9. The fluid generating device of claim 1 , wherein the teeth includes a first tooth and a second tooth, the pole face of the first tooth forms a first arc surface with a first positioning groove defined therein, the pole face of the second tooth forms a second arc surface with a second positioning groove defined thereon, and the first arc surface and the second arc surface are opposed to each other with the receiving chamber formed there between.
10. The fluid generating device of claim 9 , wherein the first tooth and the second tooth form there between a first slot opening and a second slot opening at opposite sides of the rotor, and the first slot opening and the second slot opening are symmetrical about an axis of the rotor.
11. The fluid generating device of claim 10 , wherein an angle of 60 to 65 degrees is formed between a connecting line connecting a center of the first slot opening and a center of the rotor and an extension direction of the tooth body of the first tooth.
12. The fluid generating device of claim 9 , wherein a line connecting the first positioning groove and the second positioning groove coincides with center lines of the tooth bodies of the first tooth and the second tooth.
13. The fluid generating device of claim 12 , wherein a depth of the first positioning groove into the first tooth and a depth of the second positioning groove into the second tooth are both 0.015 to 0.035 times the outer diameter of the rotor.
14. The fluid generating device of claim 12 , wherein the slot opening has a width less than or equal to fourth times of a thickness of the air gap.
15. The fluid generating device of claim 1 , wherein the single phase motor is a single phase permanent magnet direct current brushless motor or a single phase permanent magnet brushless synchronous motor.
16. An electric apparatus comprising a fluid generating device of claim 1 .
17. The electric apparatus of claim 16 , wherein the electric apparatus is a hand dryer, a hair dryer, a vacuum cleaner or an air blower.
18. The fluid generating device of claim 1 , wherein the rotor comprises a rotary shaft and a permanent magnet fixed to the rotary shaft, a thickness of the permanent magnet is 0.4 to 0.48 times an outer diameter of the rotor.
19. The fluid generating device of claim 18 , wherein a thickness of the substantially even air gap is 0.26 to 0.34 times the thickness of the permanent magnet.