Motor rotor and motor

Patent metadata

Field	Value
Publication number	US-12388307-B2
Application number	US-202318157712-A
Country	US
Kind code	B2
Filing date	Jan 20, 2023
Priority date	Jul 23, 2020
Publication date	Aug 12, 2025
Grant date	Aug 12, 2025

Abstract

This application provides a motor rotor, including a rotor iron core and a plurality of permanent magnets disposed on the rotor iron core. Coercive forces of at least some permanent magnets are continuously gradiently distributed or gradiently distributed in a multi-stage manner from the middle to both ends along at least one direction perpendicular to a magnetization direction. The permanent magnet with a gradient coercive force design is used in the motor rotor. A coercive force of the permanent magnet is continuously gradiently distributed or gradiently distributed in a multi-stage manner from the middle to both ends. In this way, a coercive force change of the entire permanent magnet is uniform, and stability and reliability of the motor can be maximized. In addition, this can avoid excessive anti-demagnetization performance, reduce an amount of usage of heavy rare earth elements, and minimize costs of the motor.

First claim

What is claimed is:

1. A motor rotor, comprising:
a rotor iron core; and
a plurality of permanent magnets disposed on the rotor iron core, wherein at least some permanent magnets of the plurality of permanent magnets comprise concentrations of rare earth metallic elements continuously gradiently distributed or gradiently distributed in a multi-stage manner from a middle to both ends in a first trend along at least one direction perpendicular to a magnetization direction;
wherein the concentrations of rare earth metallic elements result in coercive forces of the at least some permanent magnets of the plurality of permanent magnets in a second trend along the at least one direction perpendicular to the magnetization direction, wherein the second trend proportionally corresponds to the first trend; and
wherein the concentrations of rare earth metallic elements result in magnetic forces of the at least some permanent magnets of the plurality of permanent magnets in a third trend along the at least one direction perpendicular to the magnetization direction, wherein the third trend proportionally corresponds to the first trend.

2. The motor rotor according to claim 1 , wherein the second trend of the coercive forces of the at least some permanent magnets of the plurality of permanent magnets from the middle to both ends along the at least one direction perpendicular to the magnetization direction is as follows: continuously gradiently increasing or gradiently increasing in a multi-stage manner.

3. The motor rotor according to claim 1 , wherein the at least some permanent magnets of the plurality of permanent magnets are in an integrally molded structure.

4. The motor rotor according to claim 1 , wherein the at least some permanent magnets of the plurality of permanent magnets are formed by splicing a plurality of sections of magnets with different coercive forces.

5. The motor rotor according to claim 1 , wherein a coercive force gradient degree at both ends of a permanent magnet of the plurality of permanent magnets is greater than a coercive force gradient degree in a middle part.

6. The motor rotor according to claim 1 , wherein along the direction perpendicular to the magnetization direction, the at least some permanent magnets of the plurality of permanent magnets comprise a center section and end sections located at both ends of the center section, and at least one transition section is further comprised between the center section and the end section.

7. The motor rotor according to claim 6 , wherein along the direction perpendicular to the magnetization direction, a width of the center section is more than 30% of a total width of the at least some permanent magnets of the plurality of permanent magnets.

8. The motor rotor according to claim 6 , wherein along the direction perpendicular to the magnetization direction, a width of the end section is less than 10% of the total width of the at least some permanent magnets of the plurality of permanent magnets.

9. The motor rotor according to claim 6 , wherein a minimum coercive force of the end section is more than 30% greater than a minimum coercive force of the center section.

10. The motor rotor according to claim 6 , wherein when the coercive force of the end section is continuously gradiently distributed, a difference between a maximum coercive force and the minimum coercive force of the end section is from 5% to 30%.

11. The motor rotor according to claim 6 , wherein one transition section is comprised between the center section and the end section, and the at least some permanent magnets of the plurality of permanent magnets are in a five-section structure.

12. The motor rotor according to claim 1 , wherein along the direction perpendicular to the magnetization direction, the coercive forces of the at least some permanent magnets of the plurality of permanent magnets from the middle to both ends is symmetrically distributed or asymmetrically distributed.

13. The motor rotor according to claim 1 , wherein a plurality of magnetic steel grooves are provided on the rotor iron core, and the plurality of permanent magnets are disposed in the plurality of magnetic steel grooves in a one-to-one correspondence.

14. The motor rotor according to claim 13 , wherein on the rotor iron core, a positioning protrusion configured to fix the plurality of permanent magnets is provided on a side, of two ends of the magnetic steel groove, that is away from a rotating shaft of the rotor iron core.

15. The motor rotor according to claim 14 , wherein a peripheral surface of the positioning protrusion is an arc-shaped curved surface.

16. The motor rotor according to claim 14 , wherein a groove connected to the positioning protrusion is further provided on the rotor iron core, and the groove is located on a side, of the positioning protrusion, that is close to a middle part of the magnetic steel groove.

17. The motor rotor according to claim 1 , wherein the plurality of permanent magnets are sintered neodymium iron boron magnets.

18. The motor rotor according to claim 1 , wherein the plurality of permanent magnets are attached to a peripheral surface of the rotor iron core.

19. A motor, comprising:
a stator; and
a motor rotor, comprising:
a rotor iron core; and
a plurality of permanent magnets disposed on the rotor iron core, wherein at least some permanent magnets of the plurality of permanent magnets comprise concentrations of rare earth metallic elements continuously gradiently distributed or gradiently distributed in a multi-stage manner from a middle to both ends in a first trend along at least one direction perpendicular to a magnetization direction;

wherein the concentrations of rare earth metallic elements result in coercive forces of the at least some permanent magnets of the plurality of permanent magnets in a second trend along the at least one direction perpendicular to the magnetization direction, wherein the second trend proportionally corresponds to the first trend; and
wherein the concentrations of rare earth metallic elements result in magnetic forces of the at least some permanent magnets of the plurality of permanent magnets in a third trend along the at least one direction perpendicular to the magnetization direction, wherein the third trend proportionally corresponds to the first trend.

20. The motor according to claim 19 , wherein the second trend of the coercive forces of the at least some permanent magnets of the plurality of permanent magnets from the middle to both ends along the at least one direction perpendicular to the magnetization direction is as follows: continuously gradiently increasing or gradiently increasing in a multi-stage manner.

Assignees

• Huawei Digital Power Tech Co Ltd

Inventors

• Lai Bin
• Lan Hua
• Li Mengde
• Wang Zijing

Classifications

• H02K21/14

  with magnets rotating within the armatures · CPC title

• H02K1/02

  characterised by the magnetic material · CPC title

• H01F41/028

  Radial anisotropy (for rotor or stator bodies H02K15/02) · CPC title

• H01F41/0293

  diffusion of rare earth elements, e.g. Tb, Dy or Ho, into permanent magnets · CPC title

• H02K2213/03

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