Metal treatment – Process of modifying or maintaining internal physical... – Magnetic materials
Reexamination Certificate
1999-01-28
2001-01-23
Sheehan, John (Department: 1742)
Metal treatment
Process of modifying or maintaining internal physical...
Magnetic materials
C148S121000
Reexamination Certificate
active
06176943
ABSTRACT:
The present invention relates generally to amorphous ferromagnetic materials utilized in sensor applications in the form of wire elements.
BACKGROUND OF THE INVENTION
Magnetostrictive materials prepared from amorphous ferromagnetic alloys may be tailored to a variety of specifically different sensor applications. Such amorphous ferromagnetic materials have been previously utilized to fabricate ribbons for transformer cores and found to be very sensitive to strains and to magnetic fields. Previous work on ribbons made from such magnetoelastic materials involved annealment thereof in a transverse magnetic field for removal of mechanical strains, resulting in a transverse anisotropy and a high magnetoelastic coupling factor, as disclosed for example in U.S. Pat. No. 4,763,030 to Clark et al.
Use of magnetostrictive material in the form of elongated wire positioned on the cylindrical surface of a shaft in a torque sensor application was also previously proposed, as disclosed in U.S. Pat. No. 5,315,881 to Savage et al. According to the latter Savage et al. patent, the magnetostrictive wire may be annealed prior to positioning on the torque sensor shaft in a magnetic field predominantly directed transverse to the wire axis. Use of such wire has several advantages over ribbons in offering better uniformity, accommodating annealment for longer lengths of the magnetostrictive element and enabling inductive magnetic anistropy to be imparted therein while it is being helically wound about the shaft by twisting to control dynamic range and sensitivity.
Previous work on magnetostrictive ribbon and wire elements as respectively disclosed in the aforementioned Clark et al. and Savage et al. patents involve transverse annealing resulting in a transverse anisotropy which does not maintain cylindrical geometry of the magnetostrictive element or circular symmetry in the case of wire. Because of the aforementioned advantages of wires over ribbons, use of wire elements provides more numerous design options for tailoring amorphous ferromagnetic materials to specific sensor applications, if circular symmetry could be maintained to obtain a high magnetoelastic coupling factor. It therefore an important object of the present invention to maintain the desired circular symmetry with respect to such wire despite its annealment so as to produce a high magnetostrictive coupling factor.
SUMMARY OF THE INVENTION
In accordance with the present invention, a magnetostrictive element made of amorphous ferromagnetic material for sensor application, is in the form of an elongated wire that is initially annealed by heating to a temperature necessary to remove stresses therein induced during manufacture of the wire. In addition to such heating of the wire, a DC electric current is applied thereto during annealment so as to produce a cylindrical magnetic field maintained in the wire during cooldown following heating. The desired cylindrical or spiral magnetic anistropy is thereby achieved.
A particular stress condition is also maintained in the wire while it is being annealed. Such stress condition is produced by applying to the wire a twist, a tensile stress or a combination of both, to a preselected degree, through separately controlled introduction of twist and tensile stress.
REFERENCES:
patent: 2829047 (1958-04-01), Round et al.
patent: 3774134 (1973-11-01), Kardashian et al.
patent: 3882441 (1975-05-01), Holmen et al.
patent: 3940992 (1976-03-01), Jost et al.
patent: 4116728 (1978-09-01), Becker et al.
patent: 4249969 (1981-02-01), DeCristofare et al.
patent: 4268325 (1981-05-01), O'Handley et al.
patent: 4298409 (1981-11-01), DeChritofaro et al.
patent: 4314594 (1982-02-01), Pfeifer et al.
patent: 4497046 (1985-01-01), Savage
patent: 4716556 (1987-12-01), Raskin et al.
patent: 4763030 (1988-08-01), Clark et al.
patent: 4769091 (1988-09-01), Yoshizawa et al.
patent: 4906879 (1990-03-01), Clark et al.
patent: 5039894 (1991-08-01), Teter et al.
patent: 5259099 (1993-11-01), Banno et al.
patent: 5315881 (1994-05-01), Savage et al.
patent: 5380554 (1995-01-01), Ferrando
patent: 5935346 (1999-08-01), Couderchon et al.
Clark Arthur E.
Restorff James B.
Wun-Fogle Marilyn
Forrest John
Sheehan John
Shuster Jacob
The United States of America as represented by the Secretary of
LandOfFree
Processing treatment of amorphous magnetostrictive wires does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Processing treatment of amorphous magnetostrictive wires, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Processing treatment of amorphous magnetostrictive wires will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2469328