Method of manufacturing rotor and method of manufacturing motor

Patent metadata

Field	Value
Publication number	US-12316173-B2
Application number	US-202017598297-A
Country	US
Kind code	B2
Filing date	Jan 10, 2020
Priority date	Mar 28, 2019
Publication date	May 27, 2025
Grant date	May 27, 2025

Abstract

One aspect of a method of manufacturing a rotor of the present invention is the method of manufacturing the rotor, which includes a rotor core rotatable about a central axis and a rotor magnet fixed to an outer peripheral surface of the rotor core, the method including a magnetization step of magnetizing a first magnetic member fixed to the outer peripheral surface of the rotor core to form the rotor magnet. The rotor core has a hole recessed from a surface on one side in an axial direction of the rotor core to the other side in the axial direction. In the magnetization step, the first magnetic member is magnetized in a state where a second magnetic member made of a magnetic material is inserted into the hole.

First claim

The invention claimed is:

1. A method of manufacturing a rotor, which includes a rotor core rotatable about a central axis and a rotor magnet fixed to an outer peripheral surface of the rotor core, the method comprising:
a magnetization step of magnetizing, using a removable magnetizing yoke, a first magnetic member fixed to the outer peripheral surface of the rotor core to form the rotor magnet, wherein the first magnetic member comprises:
a first piece, magnetized to serve as a first radially magnetized portion, and
a second piece, magnetized to serve as a first non-radially magnetized portion,

wherein the rotor core has a hole recessed from a surface on one side in an axial direction of the rotor core to another side in the axial direction, and
in the magnetization step, the first magnetic member is magnetized in a state where a second magnetic member made of a magnetic material is inserted into the hole, wherein the hole is aligned with the first piece of the first magnetic member in a radial direction, the hole is radially inward from the first magnetic member, the second piece of the first magnetic member is offset from the first piece in a circumferential direction, and the magnetization step comprises:
magnetizing the first piece in the radial direction;
magnetizing the second piece in the circumferential direction; and

an extraction step of removing the second magnetic member from the hole following the magnetization step.

2. The method of manufacturing a rotor according to claim 1 , wherein in the magnetization step, the rotor core and a plurality of first magnets of the first magnetic member are positioned in the circumferential direction of the hole.

3. The method of manufacturing a rotor according to claim 2 , wherein the first magnetic member has an annular shape surrounding the rotor core, and magnetization of the first magnetic member in the magnetization step is performed using a current applied to the magnetizing yoke, wherein the magnetizing yoke is located on a radially outer side of the first magnetic member,
the magnetizing yoke includes:
an annular core back portion surrounding the first magnetic member; and
a plurality of tooth portions extending radially inward from the core back portion and arranged along the circumferential direction, and
in the magnetization step, the rotor core and the first magnetic member are positioned at positions where the hole is located on a radially inner side of the tooth portion.

4. The method of manufacturing a rotor according to claim 3 , wherein
the rotor magnet includes a plurality of magnetized portions arranged in a Halbach array along the circumferential direction,
the magnetized portions include:
a plurality of radially magnetized portions whose magnetization directions are the radial direction; and
a plurality of non-radially magnetized portions whose magnetization directions are different from the radial direction, and

the first magnetic member is configured by connecting a plurality of first magnetic member pieces, which are magnetized to serve as the magnetized portions, in the circumferential direction.

5. The method of manufacturing a rotor according to claim 4 , wherein the rotor core is a non-magnetic member made of a non-magnetic material.

6. The method of manufacturing a rotor according to claim 4 , wherein a circumferential dimension of the hole is equal to or smaller than a circumferential dimension of the radially magnetized portion.

7. The method of manufacturing a rotor according to claim 4 , wherein the hole has a line-symmetric shape with respect to a circumferential center line passing through a circumferential center of the radially magnetized portion when viewed along the axial direction.

8. A method of manufacturing a rotor, which includes a rotor core rotatable about a central axis and a rotor magnet fixed to an outer peripheral surface of the rotor core, the method comprising:
a magnetization step of magnetizing, using a removable magnetizing yoke, a first magnetic member fixed to the outer peripheral surface of the rotor core to form the rotor magnet, wherein the first magnetic member comprises:
a first piece, magnetized to serve as a first radially magnetized portion, and
a second piece, magnetized to serve as a first non-radially magnetized portion,

wherein the rotor core has a hole recessed from a surface on one side in an axial direction of the rotor core to another side in the axial direction, and
in the magnetization step, the first magnetic member is magnetized in a state where a second magnetic member made of a magnetic material is inserted into the hole, wherein the hole is aligned with the first piece of the first magnetic member in a radial direction, the hole is radially inward from the first magnetic member, the second piece of the first magnetic member is offset from the first piece in a circumferential direction, and the magnetization step comprises:
magnetizing the first piece in the radial direction; and
magnetizing the second piece in the circumferential direction, wherein a radial distance from the outer peripheral surface of the rotor core to a radially outer end of the hole is 1 millimeter (mm) or more and 5 mm or less.

9. The method of manufacturing a rotor according to claim 1 , further comprising
a fixing step of fixing the first magnetic member to the rotor core, and
wherein the first magnetic member has magnetic anisotropy.

10. A method of manufacturing a motor comprising
the method of manufacturing a rotor according to claim 1 .

11. The method of manufacturing a rotor according to claim 1 , wherein the hole is offset from the second piece in the circumferential direction.

12. The method of manufacturing a rotor according to claim 1 , wherein the hole is aligned with only the first piece of the first magnetic member in the radial direction.

13. The method of manufacturing a rotor according to claim 8 , wherein the hole is offset from the second piece of the first magnetic member in the circumferential direction.

14. The method of manufacturing a rotor according to claim 1 , wherein the extraction step further includes extracting at least one of the rotor core or the rotor magnet from the removable magnetizing yoke.

15. The method of manufacturing a rotor according to claim 1 , wherein the extraction step further includes extracting the rotor core and the rotor magnet from the removable magnetizing yoke.

16. The method of manufacturing a rotor according to claim 1 , wherein the hole has a line-symmetrical shape with respect to a circumferential center line.

Assignees

• Nidec Corp

Inventors

• Tanaka Junya
• Ueda Tomoya

Classifications

• H02K1/2713

  the magnetisation axis of the magnets being axial, e.g. claw-pole type · CPC title

• H02K15/03 Primary

  having permanent magnets · CPC title

• H02K1/2783 Primary

  with magnets arranged in Halbach arrays · CPC title