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

• US 9,941,039 B2
• Filed: 06/12/2015
• Issued: 04/10/2018
• Est. Priority Date: 06/13/2014
• Status: Active Grant

• Current Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Original Assignee: Toyota Jidosha Kabushiki Kaisha (Toyota Motor Corporation)
• Inventors: Okamoto, Daisuke, Onodera, Kiyotaka, Saigusa, Shinjiro, Ishii, Kohei, Ohtsubo, Masashi, Hwang, Junghwan, Tani, Masaaki, Hattori, Takeshi
• Primary Examiner(s): Enad, Elvin G
• Assistant Examiner(s): HOSSAIN, KAZI S
• Application Number:
  US14/737,876
• Publication Number:
  US 20150364235A1
• Time in Patent Office: 1,033 Days
• Field of Search: 336221, 336212, 336 83, 336234
• CPC Class Codes: B22F 1/16 Metallic particles coated with a non-metal coated with lubricating or binding agents or with organic material B22F1/10
• CPC Class Codes: B22F 2998/10 Processes characterised by the sequence of their steps
• CPC Class Codes: C22C 33/0257 characterised by the range of the alloying elements
• CPC Class Codes: C22C 33/0264 the maximum content of each alloying element not exceeding 5%
• CPC Class Codes: H01F 1/14791 Fe-Si-Al based alloys, e.g. Sendust
• CPC Class Codes: H01F 1/24 the particles being insulated
• CPC Class Codes: H01F 1/33 mixtures of metallic and non-metallic particles; metallic particles having oxide skin
• CPC Class Codes: H01F 27/255 made from particles H01F27/26 takes precedence
• CPC Class Codes: H01F 3/08 made from powder powder coatings on sheets H01F3/02; on strips or ribbons H01F3/04; on wires H01F3/06
• CPC Class Codes: H01F 41/0246 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

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.

Claims

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 μ

m to 450 μ

m,

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 μ

m,

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.