Method for manufacturing a wound magnetic core

Patent metadata

Field	Value
Publication number	US-11715591-B2
Application number	US-202117210714-A
Country	US
Kind code	B2
Filing date	Mar 24, 2021
Priority date	Mar 27, 2020
Publication date	Aug 1, 2023
Grant date	Aug 1, 2023

Abstract

[PROBLEM] To provide a wound magnetic core and a method for manufacturing a wound magnetic core permitting improvement of insulation between ribbon layers in a wound magnetic core at which soft magnetic metal ribbon has been wound to form an annular wound body.[SOLUTION MEANS] 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

The invention claimed is:

1. A method for manufacturing a wound magnetic core, comprising:
a first operation in which a nonmagnetic insulating metal oxide powder is made to adhere to a surface of a soft magnetic metal ribbon having an amorphous structure;
a second operation in which, following the first operation, the soft magnetic metal ribbon is wound in annular fashion to obtain a wound body at which the metal oxide powder intervenes between layers of the ribbon;
a third operation in which the wound body is made to undergo heat treatment in a nonoxidizing atmosphere;
a fourth operation in which, following the third operation, the wound body is subjected to treatment for formation of an oxide film in an oxidizing atmosphere at a temperature lower than a heat treatment temperature at the third operation to cause oxidation of the surface of the soft magnetic metal ribbon;
a fifth operation in which, following the fourth operation, spaces between the layers of the ribbon of the wound body are impregnated with resin and curing thereof is carried out;

wherein:
an amount of the metal oxide powder which is made to adhere thereto at the first operation is not less than 0.1% but not greater than 1.2% when expressed as a metal oxide powder wt % ratio as obtained using the following formula (1); and
metal oxide wt % ratio (%)=(weight of metal oxide adhering to soft magnetic metal ribbon/weight of soft magnetic metal ribbon)×100  (1).

2. The method for manufacturing the wound magnetic core according to claim 1 , wherein:
the third operation is heat treatment A that causes formation of nanocrystals at the soft magnetic metal ribbon having the amorphous structure.

3. The method for manufacturing the wound magnetic core according to claim 1 , wherein:
the third operation is heat treatment B that relieves stresses at the soft magnetic metal ribbon having the amorphous structure.

4. The method for manufacturing the wound magnetic core according to claim 2 , wherein:
a temperature at the heat treatment A of the third operation is not less than 450° C. but not greater than 620° C.

5. The method for manufacturing the wound magnetic core according to claim 3 , wherein:
a temperature at the heat treatment B of the third operation is not less than 250° C. but not greater than 400° C.

6. The method for manufacturing the wound magnetic core according to claim 1 , wherein:
the oxide film forming treatment at the fourth operation is carried out in the oxidizing atmosphere at a temperature that is not less than 240° C. but less than the heat treatment temperature at the third operation.

7. The method for manufacturing 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