Soft magnetic member, reactor, powder for dust core, and method of producing dust core

Patent metadata

Field	Value
Publication number	US-9941039-B2
Application number	US-201514737876-A
Country	US
Kind code	B2
Filing date	Jun 12, 2015
Priority date	Jun 13, 2014
Publication date	Apr 10, 2018
Grant date	Apr 10, 2018

Abstract

A soft magnetic member is formed such that, when a differential relative permeability in an applied magnetic field of 100 A/m is represented by a first differential relative permeability μ′L, and when a differential relative permeability in an applied magnetic field of 40 kA/m is represented by a second differential relative permeability μ′H, a ratio of the first differential relative permeability μ′L to the second differential relative permeability μ′H satisfies a relationship of μ′L/μ′H≤10, and a magnetic flux density in an applied magnetic field of 60 kA/m is 1.15 T or higher.

First claim

What is claimed is:

1. A dust core comprising
powder comprising soft magnetic particles each coated with an insulating film,
an average particle size of particles constituting the powder for the dust core is 20 μm to 450 μm,
the insulating film contains aluminum oxide as a major component,
the soft magnetic particles are formed of an iron-aluminum-silicon alloy,
in the iron-aluminum-silicon alloy, the Si content is 1 mass % to 7 mass %, the Al content is 1 mass % to 6 mass %, the total content of Si and Al is 1 mass % to 12 mass %, and the balance includes iron and unavoidable impurities, and
the insulating film has a Vickers hardness, which is 2.0 times or higher than that of the soft magnetic particles, and has a thickness of 150 nm to 2 μm,
wherein the dust core is formed such that, when a differential relative permeability in an applied magnetic field of 100 A/m is represented by a first differential relative permeability μ′L, and when a differential relative permeability in an applied magnetic field of 40 kA/m is represented by a second differential relative permeability μ′H, a ratio of the first differential relative permeability μ′L to the second differential relative permeability μ′H satisfies a relationship of μ′L/μ′H≤10, and a magnetic flux density in an applied magnetic field of 60 kA/m is 1.15 T or higher.

2. A reactor comprising:
a core formed of the dust core according to claim 1 ; and
a coil that is wound around the core.

Assignees

• Toyota Motor Co Ltd

Inventors

• Okamoto Daisuke
• Onodera Kiyotaka
• Saigusa Shinjiro
• Ishii Kohei
• Ohtsubo Masashi
• Hwang Junghwan
• Tani Masaaki
• Hattori Takeshi

Classifications

• B22F2998/10

  Processes characterised by the sequence of their steps · CPC title

• H01F41/0246

  Manufacturing of magnetic circuits by moulding or by pressing powder (magnetic cores made by moulding or by pressing powder H01F27/255; soft magnetic particles H01F1/20, H01F1/36) · CPC title

• H01F1/24 Primary

  the particles being insulated · 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

• H01F1/14791

  Fe-Si-Al based alloys, e.g. Sendust · CPC title