公开(公告)号：US20240186048A1

公开(公告)日：2024-06-06

申请号：US18554005

申请日：2022-03-14

Applicant: MINEBEA MITSUMI Inc.

Inventor： Haruhiro KOMURA ,  Yu OKAWARA ,  Kaoru NISHIGUCHI ,  Satoshi AIDA

IPC: H01F13/00 ,  H01F41/02

CPC classification number: H01F13/003 ,  H01F41/0253

Abstract: A permanent magnet manufacturing method according to an embodiment includes a heating step of disposing a field magnet part near a to-be-magnetized object, the field magnet part having a plurality of permanent magnets for magnetization arranged at predetermined intervals to apply a magnetization magnetic field to the to-be-magnetized object and heating the to-be-magnetized object to a temperature equal to or higher than the Curie point of the to-be-magnetized object, and a magnetization step of cooling the to-be-magnetized object having reached the temperature equal to or higher than the Curie point to a temperature lower than the Curie point and continuously applying a magnetization magnetic field to the to-be-magnetized object by the field magnet unit, and the permanent magnets for magnetization are isotropic SmCo sintered magnets in a predetermined shape.

公开(公告)号：US20230024876A1

公开(公告)日：2023-01-26

申请号：US17758474

申请日：2020-12-25

Applicant: MINEBEA MITSUMI Inc.

Inventor： Kaoru NISHIGUCHI ,  Yasuo OSADA ,  Takahiro OHARA

IPC: G01D5/14 ,  G01D5/04

Abstract: To reduce the influence of an unintended magnetic flux of a permanent magnet on detection accuracy. An absolute encoder (2) includes a magnet provided at a tip end side of any one of a first worm gear portion (11) and a second worm gear portion (22), and an angle sensor configured to detect a rotation angle of the magnet in response to a change in magnetic flux generated from the magnet. In the magnet, a first magnetic pole portion of a first polarity and a second magnetic pole portion of a second polarity different from the first polarity are formed adjacent to each other as viewed from an axial end surface of the magnet. The first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in a radial direction with a radial center of the magnet as a boundary, and the first magnetic pole portion and the second magnetic pole portion are formed adjacent to each other in an axial direction with an axial center as a boundary. The absolute encoder (2) is provided with a magnetic interference reduction member formed of a magnetic material on a radially outer peripheral surface of the magnet.

公开(公告)号：US20220155051A1

公开(公告)日：2022-05-19

申请号：US17593858

申请日：2020-03-24

Applicant: MINEBEA MITSUMI Inc.

Inventor： Norikazu SATO ,  Kaoru NISHIGUCHI ,  Hiroyuki HISHIYAMA ,  Yujin ISHI

IPC: G01B7/30 ,  G01D5/14 ,  G01D5/16

Abstract: An absolute encoder preferable in being made compact is provided.
The absolute encoder includes a worm gear, a permanent magnet (19) provided on a top end side of the worm gear, and magnetic sensors. In the permanent magnet (19), a given first polar portion (N) among first polar portions each having a first polarity and a given second polar portion (S) among second polar portions each having a second polarity different from the first polarity are formed adjacent to each other, when viewed from an end surface of the permanent magnet (19) in an axial direction thereof. A given first polar portion (N) and a given second polar portion (S) are formed to be adjacent in a radial direction, with a radial middle portion of the permanent magnet (19) that is a boundary. A given first polar portion (N) and a given second polar portion (S) are formed to be adjacent in an axial direction, with an axial middle portion of the permanent magnet (19) that is a boundary.