IP Library › Granted Patent US 12,580,433
Granted Patent B2
US 12,580,433 · App. 18/571,328 · Granted Mar 17, 2026

Rotor and motor

Inventors: Yutaka Kamogi (Kitasaku-gun, JP); Junichi Miyaki (Kitasaku-gun, JP)
Assignee: MINEBEA MITSUMI Inc.
H02K1/274
View Patent ↗
Loading inventors, assignments & file history…
Monitor This Case
Get email alerts when status or documents change.
Order Certified Copies
Most orders are placed with the USPTO same day — all within 24 business hours.
Order via The Patent Place →
Pre-filled with this patent's details
Quick Facts
Patent No.
US 12,580,433
App. No.
18/571,328
Granted
Mar 17, 2026
Kind
B2
Abstract

A rotor includes a rotor core, a magnet, and a cover. The rotor core includes an annular portion and a plurality of magnetic pole pieces. The magnet is disposed between two magnetic pole pieces adjacent to each other in a circumferential direction of the plurality of magnetic pole pieces. The cover covers an outer peripheral portion of the magnet, and is formed of a non-magnetic member or a member having magnetism lower than magnetism of the rotor core.

Claims (28)

1 . A rotor comprising:

a shaft including a first end portion and a second end portion; and

a rotor core including:

an annular portion; and

a plurality of magnetic pole pieces;

a magnet disposed between two magnetic pole pieces adjacent to each other in a circumferential direction of the plurality of magnetic pole pieces;

a cover including:

a planar portion;

a protruding portion protruding from the planar portion in an axial direction; and

an inner peripheral portion protruding directly from a first end portion side of the planar portion in the axial direction,

wherein the protruding portion of the cover covers an outer peripheral portion of the magnet in a radial direction,

wherein the inner peripheral portion of the cover is disposed between the annular portion and the shaft in a radial direction; and

the cover is formed of a non-magnetic material or a material having magnetism lower than magnetism of a material forming the magnetic pole pieces.

2 . The rotor according to claim 1 , wherein

the two adjacent magnetic pole pieces include recessed portions recessed in the radial direction.

3 . The rotor according to claim 2 , wherein

each of the recessed portions of the two adjacent magnetic pole pieces is opposed to the magnet in the circumferential direction.

4 . The rotor according to claim 1 , wherein

The cover includes an opening portion opening in an axial direction, and

the opening portion opposes the magnet in the axial direction.

5 . The rotor according to claim 1 , wherein

the rotor core includes a support portion protruding in the radial direction, and

the support portion and the magnet are in contact with each other.

6 . The rotor according to claim 1 , wherein

the cover includes a contact portion, and

the contact portion is in contact with the magnet at a radially inner side of the magnet.

7 . A motor comprising the rotor according to claim 1 .

8 . The rotor according to claim 1 , wherein a curved edge is formed between the inner peripheral portion and the first end portion side of the planar portion.

Assignments (1)
ASSIGNMENT OF ASSIGNOR'S INTEREST Recorded Jan 4, 2024
From: KAMOGI, YUTAKA; MIYAKI, JUNICHI
To: MINEBEA MITSUMI INC.
Reel/Frame 066015/0930 →
Priority Claims (1)
JP 2021-107259 · Jun 29, 2021 · national
Continuity (1)
Related Publication 20240283308A1 · Aug 22, 2024
References Cited (18)
US 11489380B2 · Ueda et al. · 2022 [cited by applicant]
US 20060097601A1 · Hauger · 2006 [cited by applicant]
US 20140191608A1 · Jang · 2014 [cited by examiner]
US 20180198334A1 · Sano et al. · 2018 [cited by applicant]
US 20200251942A1 · Ueda · 2020 [cited by examiner]
US 20220239167A1 · Maeda · 2022 [cited by examiner]
JP H05207690A · 1993 [cited by applicant]
JP 2006141197A · 2006 [cited by applicant]
JP 2012085445A · 2012 [cited by applicant]
JP 2012200053A · 2012 [cited by applicant]
JP 2018113775A · 2018 [cited by applicant]
WO 2018043288A1 · 2018 [cited by applicant]
WO 2019066004A1 · 2019 [cited by applicant]
English translation of Written Opinion for corresponding International Application No. PCT/JP2022/016030 mailed Jun. 14, 2022. [cited by applicant]
Extended European Search Report dated May 14, 2025 for corresponding European Application No. 22832547.8. [cited by applicant]
Notice of Reasons for Refusal dated Aug. 6, 2025 for corresponding Japanese Application No. 2021-107259 and English translation. [cited by applicant]
International Search Report for corresponding International Application No. PCT/JP2022/016030 mailed Jun. 14, 2022. [cited by applicant]
Written Opinion for corresponding International Application No. PCT/JP2022/016030 dated Jun. 14, 2022. [cited by applicant]