公开(公告)号：US20250037933A1

公开(公告)日：2025-01-30

申请号：US18717056

申请日：2022-11-04

Applicant: MINEBEA MITSUMI Inc.

Inventor： Yu OKAWARA ,  Haruhiro KOMURA ,  Yuki ITO ,  Heki NAKAYA

IPC: H01F41/02 ,  H01F1/057 ,  H01F13/00

Abstract: A method of producing a rare earth iron-based sintered magnet according to an embodiment includes a step of filling a mold with a rare earth iron-based magnet powder produced by a rapid quenching method, a step of setting the mold in a sintering apparatus, supplying a predetermined current from electrodes, and pressurizing and heating the rare earth iron-based magnet powder filled to produce a sintered magnet body, and a step of magnetizing the sintered magnet body with a magnetizing device. The mold includes dies having a hollow cylindrical form, punches to be inserted into the dies, and die supports made of a conductive material and respectively disposed at both ends of the dies in an axial direction. A cavity to be formed by the dies and the punches is filled with the rare earth iron-based magnet powder. The dies include an inner die made of a non-conductive material and an outer die made of a conductive material and disposed outside the inner die, inner peripheral surfaces of the die supports are in contact with an outer peripheral surface of the outer die, and the electrodes are in contact with the die supports.

公开(公告)号：US20240234028A1

公开(公告)日：2024-07-11

申请号：US18561373

申请日：2022-05-16

Applicant: MINEBEA MITSUMI Inc.

Inventor： Kentaro HANASHIMA ,  Haruhiro KOMURA

IPC: H01F41/02 ,  B22F3/00 ,  B22F3/14 ,  B22F3/16 ,  B22F3/24 ,  B22F5/10 ,  B22F9/04 ,  C22C38/00 ,  H01F1/057

CPC classification number: H01F41/0253 ,  B22F3/004 ,  B22F3/14 ,  B22F3/16 ,  B22F3/24 ,  B22F5/106 ,  B22F9/04 ,  C22C38/005 ,  H01F1/057 ,  B22F2003/248 ,  B22F2009/048 ,  B22F2201/02 ,  B22F2201/10 ,  B22F2301/355 ,  B22F2998/10 ,  B22F2999/00

Abstract: A method for manufacturing a rare-earth iron-based ring magnet includes: (a) obtaining a rare-earth iron-based magnet powder; (b) preparing a compound; (c) forming a green body; (d) inserting the green body into a composite mold, setting the composite mold in a spark plasma sintering (SPS) apparatus, and degreasing the green body by energization at a predetermined current density while applying a pressure to the green body under reduced pressure to obtain a degreased body; and (e) sintering the degreased body by energization at a current density while applying a pressure to the degreased body to obtain a rare-earth iron-based ring magnet.

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：US20250062067A1

公开(公告)日：2025-02-20

申请号：US18720751

申请日：2022-12-09

Applicant: MINEBEA MITSUMI Inc.

Inventor： Yu OKAWARA ,  Haruhiro KOMURA

IPC: H01F41/02 ,  B22F3/12 ,  H01F7/02

Abstract: A permanent magnet manufacturing method includes at least a magnetization target forming step of molding a magnetization target by applying a predetermined pressure to a magnet powder and a thermosetting resin, and a heating step of heating the magnet powder to the Curie point or higher while permanent magnets of a field magnet part are brought close to the magnetization target placed on a base member to magnetize the magnet powder and melting and curing the thermosetting resin to allow the magnetization target to fixedly adhere to the base member.

公开(公告)号：US20240274354A1

公开(公告)日：2024-08-15

申请号：US18564716

申请日：2022-05-16

Applicant: MINEBEA MITSUMI Inc.

Inventor： Yu OKAWARA ,  Haruhiro KOMURA

IPC: H01F41/02 ,  H01F13/00

CPC classification number: H01F41/0253 ,  H01F13/003

Abstract: A manufacturing method for a permanent magnet includes a magnetization step of magnetizing a to-be-magnetized object by a magnetizer including a field magnet unit having a plurality of permanent magnets for magnetization configured to generate a magnetic field on the to-be-magnetized object arranged at equal intervals and a heating unit having a heating surface opposing the to-be-magnetized object in an axial direction of the to-be-magnetized object and configured to heat the to-be-magnetized object. In the magnetization step, the to-be-magnetized object is disposed on the field magnet unit, the to-be-magnetized object is heated by the heating unit to a temperature equal to or higher than a Curie point of the to-be-magnetized object and lower than the Curie point of the permanent magnets for magnetization, and then the temperature is lowered to a temperature lower than the Curie point of the to-be-magnetized object, and a magnetization magnetic field is applied to the to-be-magnetized object by the permanent magnets for magnetization.