US4543208A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Magnetic core and method of producing the same
Assignee: Toshiba Corp
•
Filing: 1983-12-23
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Granted: 1985-09-24
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Expires: 2003-12-23
Abstract
Abstract Disclosed is an magnetic core comprising a molded product made of an iron powder and/or an iron alloy magnetic powder having a mean particle size of 10 to 100 mu m, and 1.5 to 40%, as a total amount in terms of volume ratio, of an insulating binder resin and an insulating inorganic compound powder. Also disclosed is a useful method of producing the magnetic core.
Inventors
- 👤 Hiromichi Horie
- 👤 Mikio Morita
- 👤 Itsuo Arima
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 15:24
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/24; H01F27/255; B; B22; B22F; B22F1/00; B22F1/10; H01F1/00; H01F1/01; H01F1/03; H01F1/12; H01F1/14; H01F1/20; H01F1/22; H01F1/24; H01F1/26
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
63 words
A magnetic core, which comprises a compression molded product comprising: a soft magnetic material selected from an iron powder, an iron alloy magnetic powder, and combinations thereof, said material having a mean particle size of 10 to 100 μm; and 1.5 to 40%, as a total amount in terms of volume ratio, of insulating binder resin and a non-ferrite insulating inorganic compound powder.
Claim 2
Dependent Claim
63 words
A magnetic core, which comprises a compression molded product comprising: a soft magnetic material selected from an iron powder, an iron alloy magnetic powder, and combinations thereof, said material having a mean particle size of 10 to 100 μm; and 1.5 to 40%, as a total amount in terms of volume ratio, of insulating binder resin and a non-ferrite insulating inorganic compound powder.
Claim 3
Dependent Claim
53 words
The magnetic core according to claim 1, wherein said iron powder or iron alloy magnetic powder, when its mean particle size is represented by D μm and its resistivity by ρμΩ·cm, satisfies the relationship, when represented in terms of only the numerical values of ρ and D, of ρ/D 2 >4×10 -3 .
Claim 4
Dependent Claim
22 words
The magnetic core according to claim 1, wherein said inorganic compound powder has a mean particle size of 20 μm or less.
Claim 5
Dependent Claim
44 words
The magnetic core according to claim 1, wherein said iron powder or iron alloy magnetic powder is at least one selected from the group consisting of Fe powder, Fe-Si alloy powder, Fe-Al alloy powder, Fe-Si-Al alloy powder, Fe-Ni alloy powder and Fe-Co alloy powder.
Claim 6
Dependent Claim
40 words
The magnetic core according to claim 1, wherein said insulating binder resin is at least one selected from the group consisting of epoxy resins, polyamide resins, polyimide resins, polyester resins, polycarbonate resins, polyacetal resins, polysulfone resins and polyphenylene oxide resins.
Claim 7
Dependent Claim
36 words
The magnetic core according to claim 1, wherein said insulating inorganic compound powder is powder of at least one compounds selected from the group consisting of calcium carbonate, silica, magnesia, alumina, red iron oxide and glass.
Claim 8
Dependent Claim
35 words
The magnetic core according to claim 6, wherein said insulating inorganic compound powder has mean particle size of 1/5 or less of the mean particle size of the iron powder or iron alloy magnetic powder.
Claim 9
Dependent Claim
27 words
The magnetic core according to claim 1, wherein the total amount of said binder resin and said inorganic compound powder ranges from 1.5 to 40 vol %.
Claim 10
Dependent Claim
29 words
The magnetic core according to claim 8, wherein the ratio of said binder resin and said inorganic compound powder is 98 to 20 vol. %:2 to 80 vol. %.
Claim 11
Independent Claim
61 words
A method of producing an magnetic core, which comprises a step of preparing a binder by mixing an insulating inorganic compound powder with a resin, a step of grinding said binder into a powder to prepare a powdery binder, and a step of mixing and compression molding said powdery binder with iron powder, iron alloy magnetic powder or a mixture thereof.
Claim 12
Independent Claim
61 words
A method of producing an magnetic core, which comprises a step of preparing a binder by mixing an insulating inorganic compound powder with a resin, a step of grinding said binder into a powder to prepare a powdery binder, and a step of mixing and compression molding said powdery binder with iron powder, iron alloy magnetic powder or a mixture thereof.
Claim 13
Dependent Claim
22 words
The method according to claim 10, wherein the compression molding is carried out under the pressure of from 100 to 1000 MPa.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1988-09-23 | 1989-03-25 | 1989-09-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-09-23 | 1993-03-25 | 1993-09-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-09-23 | 1997-03-25 | 1997-09-24 | $7700.00 | Window Closed / Lapsed |