Rotor assembly and stator assembly for an electrical machine

• US 20040217667A1
• Filed: 01/16/2004
• Published: 11/04/2004
• Est. Priority Date: 02/18/2003
• Status: Active Grant

• Current Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Original Assignee: Minebea Company Limited (MinebeaMitsumi Inc.)
• Inventors: Popov, Vladimir Vladimirovich
• Granted Patent: US 6,967,424 B2
• Time in Patent Office: Days
• US Class Current: 310/156.57
• CPC Class Codes: H02K 1/146 consisting of a generally annular yoke with salient poles
• CPC Class Codes: H02K 1/2766 having a flux concentration effect
• CPC Class Codes: H02K 2201/06 Magnetic cores, or permanent magnets characterised by their skew
• CPC Class Codes: H02K 29/03 with a magnetic circuit specially adapted for avoiding torque ripples or self-starting problems

Abstract

The present invention relates to a rotor assembly for an electrical machine, comprising: a rotor body of generally cylindrical shape having a substantially cylindrical surface configured for facing an air-gap between the rotor assembly and a stator of the electrical machine, and permanent magnets embedded in said rotor body, wherein grooves are formed in said air-gap facing surface for manipulating the distribution of magnetic flux created by said permanent magnets.

Claims

1. A Rotor assembly for an electrical machine, comprising:

a rotor body of substantially cylindrical shape having an outer surface facing an gap between the rotor assembly and a stator of the electrical machine, and

a plurality of permanent magnets embedded in said rotor body,

wherein the outer surface of the rotor body defines at least one groove for manipulating the distribution of magnetic flux of said permanent magnets.

2. The rotor assembly according to claim 1, wherein the embedded magnets extend substantially radially through said rotor body.

3. The rotor assembly according to claim 1, wherein said at least one groove axially extends along the outer surface of the rotor body.

4. The rotor assembly according to claim 1, wherein the rotor body further comprises a plurality of cylindrical laminations (10).

12. The rotor assembly according to claim 1, wherein said groove is disposed about an end face of at least one of said permanent magnets.

13. The rotor assembly according to claim 4, wherein each lamination includes at least one notch (20) on a surface thereof.

14. The rotor assembly according to claim 13, wherein a plurality of laminations each including at least one notch are arranged on the rotor body to form a groove (20).

15. The rotor assembly according to claim 14, wherein said groove (20) is axially aligned with an axis of the rotor.

16. The rotor assembly according to claim 14, wherein said groove (20) is not axially aligned with an axis of the rotor.

17. The rotor assembly according to claim 14, wherein said groove (20) is skewed with respect to an axis of the rotor.

23. The Rotor assembly according to claim 1, further comprising a stator.

5. (Cancelled.)

6. A Stator assembly for an electrical machine, comprising:

a stator body of having stator poles (42), said stator poles (42) having end faces facing an air-gap between the stator assembly and a rotor of the electrical machine,

wherein at least one groove (40) is formed in said end faces of said stator poles (42).

7. The Stator assembly according to claim 6, wherein the at least one groove (40) is skewed.

8. The Stator assembly according to claim 6, wherein the stator body further comprises a plurality of laminated sheets (30), each sheet including a yoke section (32) and stator pole sections (34).

18. The Stator assembly according to claim 6, wherein the at least one groove extends along the length of said end faces (42) about the axial direction of the stator body.

19. The Stator assembly according to claim 8, wherein the end face of at least one pole section defines a notch (36).

20. The Stator assembly according to claim 19, wherein said laminated sheets (30) are arranged such that the at least one groove (40) extends along an axial length of the stator assembly.

21. The Stator assembly according to claim 19, wherein said at least one groove (40) extending along the axial length of the stator assembly is skewed.

22. The Stator assembly according to claim 6, further comprising a rotor.

9. (Cancelled.)

10. (Cancelled.)

11. (Cancelled.)

24. An electrical machine comprising a substantially cylindrical stator 118 concentrically aligned with a rotor 116, the outer surface of the rotor 116 and the inner surface of the stator 118 defining a substantially cylindrical gap, the gap having a plurality of protrusions 20 for manipulating an internal magnetic flux.

25. The electrical machine of claim 24, wherein the plurality of protrusions are defined by a groove in at least one of the outer surface of the rotor or the inner surface of the stator.

26. The electrical machine of claim 24, wherein the stator further comprises at least one stator pole.

27. The electrical machine of claim 24, wherein the plurality of protrusions extend axially along the length of the gap.

28. The electrical machine of claim 24, wherein the plurality of protrusions skewedly extend along the length of the gap.

29. An electric motor comprising a stator substantially housing a rotor, the rotor having an outer surface and a body, the body adapted to receive at least one magnetic element (12) and the outer surface having a notch (20) formed thereon.

30. The electric motor of claim 29, wherein the rotor further comprises several layers (10) of lamination.

31. The electric motor of claim 29, wherein the outer surface has a plurality of notches.

32. The electric motor of claim 31, wherein the plurality of notches are randomly distributed on the outer surface 16 of the rotor.

33. The electric motor of claim 29, wherein the notch (20) forms a groove along an axial length of the rotor.

34. The electric motor of claim 33, wherein the groove is skewed with respect to an axis of the motor.

35. An electric motor comprising a stator (38) for receiving a rotor, the stator (38) having a plurality of poles 34 stemming from the stator body toward the rotor, the rotor having an outer surface facing the plurality of poles;

wherein at least one of said poles defines a groove (40) at an end surface facing the outer surface of the rotor.

36. The electric motor of claim 35, wherein the groove extends axially along an axis of the stator.

37. The electric motor of claim 35, wherein the groove extend skewedly along an axis of the stator.

38. The electric motor of claim 35, wherein the groove manipulates a magnetic flux of the rotor.