US4715904A
Expired / Lapsed
US
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Method for producing a magnet with radial magnetic anisotropy
Assignee: Yamaha Corp
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Filing: 1984-02-24
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Granted: 1987-12-29
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Expires: 2004-02-24
Abstract
Abstract In production of a permanent magnet by forming a roll of an elongated magnetic metal strap, a strap made from a spinodal decomposition type magnetic alloy is subjected, at least before formation into a roll, to age-hardening under concurrent magnetization in order to obtain a magnet having significant radial magnetic anisotropy well suited for use in sound systems such as loudspeakers.
Inventors
- 👤 Kenzaburo Iijima
- 👤 Yoshinori Hayashi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 15:30
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/02; H01F41/0253; H01F41/0273; H01F41/028; C; C21; C21D; C21D1/00; C21D1/04; C21D9/00; C21D9/52; H01F7/00; H01F7/02; H01F7/0205; H01F7/021
Claims Analysis
Total Claims: 19
Claim 1
Independent Claim
61 words
A method for producing a magnet having radial magnetic anisotropy comprising the steps of forming a thin, elongated strap from a Cu--Ni--Fe spinodal decomposition type alloy which can be provided with magnetic anisotropy, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking up said strap, after age-hardening, into a light, hollow roll of a prescribed shape.
Claim 2
Independent Claim
61 words
A method for producing a magnet having radial magnetic anisotropy comprising the steps of forming a thin, elongated strap from a Cu--Ni--Fe spinodal decomposition type alloy which can be provided with magnetic anisotropy, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking up said strap, after age-hardening, into a light, hollow roll of a prescribed shape.
Claim 3
Independent Claim
70 words
A method for producing a magnet having radial magnetic anisotropy comprising the steps of forming a thin, elongated strap from a Fe--Cr--Co spinodal decomposition type alloy which can be provided with magnetic anisotropy, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking up said strap, after age-hardening, into a tight, hollow roll of a prescribed shape, subjecting said roll of said strap to additional age-hardening.
Claim 4
Independent Claim
70 words
A method for producing a magnet having radial magnetic anisotropy comprising the steps of forming a thin, elongated strap from a Fe--Cr--Co spinodal decomposition type alloy which can be provided with magnetic anisotropy, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking up said strap, after age-hardening, into a tight, hollow roll of a prescribed shape, subjecting said roll of said strap to additional age-hardening.
Claim 5
Dependent Claim
21 words
A method as claimed in claim 1 further comprising the step of subjecting said roll of said strap to additional age-hardening.
Claim 6
Dependent Claim
34 words
A method as claimed in claim 2 in which said Fe--Cr--Co type magnetic alloy contains 2 to 30% by weight of Cr, 5 to 37% by weight of Co, and Fe substantially the balance.
Claim 7
Dependent Claim
34 words
A method as claimed in claim 4 in which said Fe--Cr--Co type magnetic alloy further contains 0.1 to 8% by weight in full of at least one of Ti, Zr, Ni, V and Si.
Claim 8
Independent Claim
30 words
A method as claimed in either of claims 3 or 2 in which said first-named age-hardening is carried out at a temperature conducive to spinodal decomposition of said magnetic alloy.
Claim 9
Dependent Claim
60 words
A method as claimed in claim 6 in which said first-named age-hardening is carried out by heating said strap at a temperature in a range of 670° to 720° C. for a period of 10 to 60 minutes, lowering the temperature down to 600° to 620° C. at a rate of 10° to 90° C./hr, and quickly cooling the strap.
Claim 10
Independent Claim
31 words
A method as claimed in either of claims 3 or 2 in which intensity of the magnetic field at said first-named age-hardening is in a range from 16,000 to 400,000 A/m.
Claim 11
Independent Claim
36 words
A method as claimed in either of claims 3 or 2 in which said second-named age-hardening is carried out by gradually lowering the heating temperature of said roll of said strap from 620° to 500° C.
Claim 12
Independent Claim
21 words
A method as claimed in either of claims 3 or 2 in which said second-named age-hardening is performed with concurrent magnetization.
Claim 13
Independent Claim
20 words
A method as claimed in either of claims 3 or 2 in which said second-named age-hardening is performed without magnetization.
Claim 14
Dependent Claim
27 words
A method as claimed in claim 8 in which intensity of the magnetic field at said first-named age-hardening is in the range from 64,000 to 400,000 A/m.
Claim 15
Dependent Claim
16 words
A method as claimed in claim 7 in which said second-named age-hardening is performed without magnetization.
Claim 16
Independent Claim
82 words
A method for producing a magnet comprising the steps of forming a thin, elongated strap from a Cu--Ni--Fe spinodal decomposition type magnetic alloy which can be provided with magnetic anisotropy, said alloy containing 10 to 30% by weight of Ni, 10 to 30% by weight of Fe and the balance being substantially Cu, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking-up of said strap after said age-hardening onto a tight, hollow roll of a prescribed shape.
Claim 17
Independent Claim
82 words
A method for producing a magnet comprising the steps of forming a thin, elongated strap from a Cu--Ni--Fe spinodal decomposition type magnetic alloy which can be provided with magnetic anisotropy, said alloy containing 10 to 30% by weight of Ni, 10 to 30% by weight of Fe and the balance being substantially Cu, subjecting said strap to age-hardening under concurrent magnetization in its thickness direction, and taking-up of said strap after said age-hardening onto a tight, hollow roll of a prescribed shape.
Claim 18
Dependent Claim
21 words
A method as claimed in claim 14 further comprising the step of subjecting said roll of said strap to additional age-hardening.
Claim 19
Dependent Claim
28 words
A method as claimed in claim 15 in which said alloy contains 15-25% by weight of Ni, 15-25% by weight of Fe and the balance being substantially Cu.
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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) | 1990-12-28 | 1991-06-29 | 1991-12-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1994-12-28 | 1995-06-29 | 1995-12-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1998-12-28 | 1999-06-29 | 1999-12-29 | $7700.00 | Window Closed / Lapsed |