Rotary electric machine and electric power steering apparatus

Patent metadata

Field	Value
Publication number	US-10910892-B2
Application number	US-201515562980-A
Country	US
Kind code	B2
Filing date	Apr 22, 2015
Priority date	Apr 22, 2015
Publication date	Feb 2, 2021
Grant date	Feb 2, 2021

Abstract

In the rotary electric machine according to the present invention, a plurality of core sheets include linked core sheets that include linking portions that protrude circumferentially from flange portions so as to link together tip portions of adjacent tooth portions, at least one sheet of the linked core sheets is formed such that a tooth tip portion shape is mirror-asymmetrical relative to a tooth central axis that passes through a circumferential center of the tooth portions, and a stator core is configured by laminating the linked core sheets such that circumferential positions of the linking portions are offset.

First claim

The invention claimed is:

1. A rotary electric machine comprising:
a stator comprising:
a stator core that is configured by laminating in an axial direction a plurality of core sheets that are made of a magnetic material; and
a stator winding that is mounted to said stator core; and
a rotor that is disposed coaxially inside said stator so as to have a magnetic air gap interposed, said rotor having a plurality of field poles,
wherein:
said plurality of core sheets each comprise:
an annular core back portion;
a plurality of tooth portions that are arranged at a uniform angular pitch in a circumferential direction such that each protrudes radially inward from said core back portion;
slot portions that are formed between adjacent teeth portions; and
flange portions that protrude circumferentially from a protruding end of each of said tooth portions;
said plurality of core sheets comprise linked core sheets that comprise linking portions that protrude circumferentially from said flange portions so as to link together tip portions of said adjacent tooth portions;
at least one sheet of said linked core sheets is formed such that a tooth tip portion shape is mirror-asymmetrical relative to a tooth central axis that passes through a circumferential center of said tooth portions; and
said stator core is configured by laminating said linked core sheets such that circumferential positions of said linking portions are offset.

2. The rotary electric machine according to claim 1 , wherein said stator core is configured by laminating a plurality of core blocks that are each configured by laminating said linked core sheets such that circumferential positions of said linking portions are identical.

3. The rotary electric machine according to claim 2 , wherein:
said rotor is configured by disposing a plurality of rotor blocks in an axial direction such that circumferential positions of said field poles are offset in a circumferential direction; and
said plurality of rotor blocks each face said plurality of core blocks in which said circumferential positions of said linking portions are different across said magnetic air gap portion.

4. The rotary electric machine according to claim 1 , wherein:
said stator core is configured by laminating N types of core blocks that are each configured by laminating said linked core sheets such that circumferential positions of said linking portions are identical, where N is a natural number that is greater than or equal to 2; and
two core blocks adjacent to each other among said N types of core blocks are laminated such that said circumferential positions of said linking portions are offset by an angular difference of θs°/(N−1) from each other in said circumferential direction, where Os° is an angular difference between said linking portions of a first core block and an Nth core block in the laminating direction of said N types of core blocks.

5. The rotary electric machine according to claim 4 , wherein:
1-≤α≤1.2 is satisfied,
where said N is 2, a number of orders of torque pulsation is Ntr, a number of magnetic field poles is p, and a=θs/(360/Ntr/p).

6. The rotary electric machine according to claim 4 , wherein block boundary surfaces between said laminated core blocks exist at (N−1) positions.

7. The rotary electric machine according to claim 1 , wherein at least one sheet of said linked core sheets is formed such that said tooth tip portion shape is mirror-symmetrical relative to said tooth central axis that passes through said circumferential center of said tooth portions.

8. The rotary electric machine according to claim 1 , wherein said plurality of core sheets further include open core sheets that comprise opening portions between tip portions of said adjacent tooth portions.

9. The rotary electric machine according to claim 8 , wherein:
at least one sheet of said open core sheet is formed such that said tooth tip portion shape is mirror-asymmetrical relative to said tooth central axis that passes through said circumferential center of said tooth portions; and
said stator core is configured by laminating said open core sheets such that circumferential positions of said opening portions are offset.

10. The rotary electric machine according to claim 8 , wherein said stator core is configured by laminating a plurality of core blocks that are each configured by laminating said linked core sheets and said open core sheets such that circumferential positions of said linking portions and circumferential positions of said opening portions are identical.

11. The rotary electric machine according to claim 10 , wherein a ratio of a number of laminated sheets of said open core sheets relative to a number of laminated sheets of said linked core sheets is equal in all of said plurality of core blocks.

12. The rotary electric machine according to claim 10 , wherein:
said open core sheets are disposed at block boundary surfaces of said core blocks; and
a circumferential width of said opening portions of said open core sheets that are disposed at said block boundary surfaces is wider than a circumferential width of said linking portions.

13. The rotary electric machine according to claim 1 , wherein said linked core sheets are formed such that a radial width of said linking portions is narrower than a radial width of said flange portions.

14. The rotary electric machine according to claim 13 , wherein indented portions that are indented radially outward are formed on inner circumferential surfaces of said linking portions of said linked core sheets that face said rotor.

15. The rotary electric machine according to claim 1 , wherein each of said plurality of core sheets is formed such that said flange portions protrude from said protruding end of each of said tooth portions only on one circumferential side.

16. The rotary electric machine according to claim 15 , wherein said tooth tip portions of said linked core sheets in which said tooth tip portion shape is asymmetrical relative to said tooth central axis are formed so as to exceed θt/2 in a first circumferential direction from said tooth central axis, where θt is a pitch angle of said tooth portions.

17. The rotary electric machine according to claim 1 , wherein said stator winding is configured by inserting a plurality of coil segments that are formed so as to have a U shape from a first axial end of said stator core so as to be in two different slots each, and joining together coil terminals of said plurality of coil segments that protrude from said slots at a second axial end.

18. The rotary electric machine according to claim 1 , wherein a circumferential width near tip ends of each of said tooth portions of said plurality of core sheets is wider than a minimum circumferential width of said tooth portions.

19. The rotary electric machine according to claim 1 , wherein each of said slot portions of said plurality of core sheets is formed so as to have a trapezoidal cross-sectional shape.

20. The rotary electric machine according to claim 1 , wherein
said plurality of core sheets are each divided into two portions including a portion in a vicinity of said core back portion and a portion in a vicinity of said tooth portions.

21. The rotary electric machine according to claim 1 , wherein:
said stator winding comprises:
a first three-phase winding that comprises a U1-phase winding, a V1-phase winding, and a W1-phase winding; and
a second three-phase winding that comprises a U2-phase winding, a V2-phase wi

Assignees

• Mitsubishi Electric Corp

Inventors

• HIROTANI Yu
• Ito Kazumasa
• Takizawa Yuji
• Akutsu Satoru
• Aida Hiroshi
• Hori Shusuke

Classifications

• H02K29/03 Primary

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

• H02K1/2746

  the rotor consisting of magnets arranged with the same polarity, e.g. consequent pole type · CPC title

• H02K1/18

  Means for mounting or fastening magnetic stationary parts on to, or to, the stator structures · CPC title

• H02K2201/06

  Magnetic cores, or permanent magnets characterised by their skew · CPC title

• H02K1/146

  consisting of a generally annular yoke with salient poles · CPC title