Wound magnetic core

Patent metadata

Field	Value
Publication number	US-12191071-B2
Application number	US-202318330568-A
Country	US
Kind code	B2
Filing date	Jun 7, 2023
Priority date	Mar 27, 2020
Publication date	Jan 7, 2025
Grant date	Jan 7, 2025

Abstract

A nonmagnetic insulating metal oxide powder is made to adhere to a surface of a soft magnetic metal ribbon having an amorphous structure; this is wound in annular fashion and made into a wound body at which the metal oxide powder intervenes between ribbon layers; the wound body is made to undergo heat treatment in a nonoxidizing atmosphere; the wound body is thereafter subjected to treatment for formation of an oxide film in an oxidizing atmosphere adjusted to be at a temperature lower than that at the heat treatment to cause oxidation of the surface of the soft magnetic metal ribbon; and spaces between ribbon layers at the wound body are moreover impregnated with resin and curing is carried out to fuse the metal oxide powder thereto.

First claim

What is claimed is:

1. A wound magnetic core in which a soft magnetic metal ribbon is wound, the wound magnetic core being such that:
the soft magnetic metal ribbon has an amorphous structure and/or a nanocrystalline structure;
a layer of an oxide of Fe derived from a metal making up the soft magnetic metal ribbon is present at a surface of the soft magnetic metal ribbon;
spaces between layers of the soft magnetic metal ribbon have a nonmagnetic insulating metal oxide powder in intervening fashion and are impregnated with a resin; and
a space factor of the wound magnetic core is not less than 65% but not greater than 75%.

2. The wound magnetic core according to claim 1 , wherein:
the Fe oxide layer comprises hematite (Fe 2 O 3 ).

3. The wound magnetic core according to claim 1 , wherein:
an absolute value of a percent change in impedance at a frequency of 1 MHz as obtained using a following formula (2) is not greater than 20%; and
percent change in impedance (%)={(impedance before impulse testing-impedance after impulse testing)/impedance before impulse testing}×100  (2).

4. The wound magnetic core according to claim 1 , wherein:
the Fe oxide layer comprises hematite (Fe 2 O 3 );
an absolute value of a percent change in impedance at a frequency of 1 MHz as obtained using a following formula (2) is not greater than 20%; and
percent change in impedance (%)={(impedance before impulse testing-impedance after impulse testing)/impedance before impulse testing}×100  (2).

5. The wound magnetic core according to claim 1 , wherein:
the metal oxide is magnesium oxide (MgO), titanium oxide (TiO 2 ), or aluminum oxide (Al 2 O 3 ).

Assignees

• Proterial Ltd

Inventors

• NAKADA Tsugitomo

Classifications

• H01F41/0226

  from amorphous ribbons · CPC title

• H01F27/25

  made from strips or ribbons (H01F27/26 takes precedence) · CPC title

• H01F3/08

  made from powder (powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06) · CPC title

• H01F1/24

  the particles being insulated · CPC title

• H01F1/15308

  based on Fe/Ni (H01F1/15325 takes precedence) · CPC title