Title:
モータ用永久磁石を用いた直流モータ
Document Type and Number:
Japanese Patent JP6720123
Kind Code:
B2
Abstract:
To provide a permanent magnet for a motor formed from isotropic Nd-Fe-B magnetic powder and reduced in cogging torque.SOLUTION: A permanent magnet for a motor is a permanent magnet for a cylindrical motor with four magnetic poles and is a bond magnet containing isotropic Nd-Fe-B magnetic particles and binder resin hardening substance. The outer periphery of a cross-section is shaped such that respective end parts of two pairs of opposite sides are connected by curved parts. The inner periphery of the cross-section is circular. In the center of the magnetic pole formed in the thickest part between the inner periphery and the outer periphery in a radial direction of the circle, the direction of the magnetic vector is parallel or substantially parallel to the thickness direction of the thickest part. In the boundary of a magnetic pole formed in the thinnest part of the thickness between the inner periphery and the outer periphery in the radial direction of the circle, the direction of the magnetic vector is perpendicular or substantially perpendicular to the thickness direction of the thinnest part. The rate at which the angle of the magnetic vector changes in a range of ±10° from the boundary of the magnetic pole is 1.55 or greater but 1.85 or less.SELECTED DRAWING: Figure 1
Inventors:
Oya Shiho
Osamu Yamada
Osamu Yamada
Application Number:
JP2017178091A
Publication Date:
July 08, 2020
Filing Date:
September 15, 2017
Export Citation:
Assignee:
MinebeaMitsumi Co., Ltd.
International Classes:
H02K1/17; H02K23/04
Domestic Patent References:
| JP2010130724A | ||||
| JP2014090125A | ||||
| JP2004056835A |
Foreign References:
| US20060279159 |
Attorney, Agent or Firm:
Toranomon Intellectual Property Office