Patents by Inventor Yoshihito Yoshizawa
Yoshihito Yoshizawa has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5725686Abstract: A pulse transformer comprising a magnetic core formed of a thin strip of nanocrystalline soft magnetic alloy in which fine nanocrystalline grains having a grain size of not more than 50 nm occupy at least 50 volume % of the structure, characterized in that the AC relative initial magnetic permeability at -20.degree. C. and 50.degree. C. is not less than 50000.Type: GrantFiled: July 20, 1994Date of Patent: March 10, 1998Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Yoshio Bizen, Shin Nakajima, Shunsuke Arakawa
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Patent number: 5658398Abstract: There is provided an alloy with ultrafine crystal grains excellent in corrosion resistance, at least 50% of the alloy structure being occupied by ultrafine crystal grains, the alloy having a surface layer containing hydroxide components in a total proportion of 65% or more based on oxide components.Type: GrantFiled: April 5, 1996Date of Patent: August 19, 1997Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Shunsuke Arakawa, Katsuhisa Sugimoto
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Patent number: 5635828Abstract: An active filter circuit including a smoothing filter including a choke coil comprising a magnetic core composed of a nanocrystalline alloy and having a magnetic gap in at least one portion thereof and at least one conductive wire wound around the magnetic core, the nanocrystalline alloy having a composition of 0.1-3 atomic % of at least one element selected from the group consisting of Cu and Au, 1-7 atomic % of at least one element selected from the group consisting of Ti, Zr, Hf, V, Nb, Ta, Mo and W, 10-17 atomic % of Si, and 4-10 atomic % of B, the balance being substantially Fe and inevitable impurities.Type: GrantFiled: November 23, 1994Date of Patent: June 3, 1997Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Tooru Abe, Shin Nakajima, Shunsuke Arakawa
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Patent number: 5611871Abstract: A method for producing a nanocrystalline alloy wherein an amorphous alloy is heat-treated by keeping the temperature at a first heat treatment temperature higher than the crystallization temperature of the amorphous alloy for 0 to less than 5 minutes, and is cooled to room temperature at a cooling rate of 20.degree. C./min or more at least until the temperature falls to 400.degree. C. The amorphous alloy subjected to the first heat treatment may be further heat-treated at a second heat treatment temperature not higher than 500.degree. C. and lower than the first heat treatment temperature while applying a magnetic field. The nanocrystalline alloy produced by the method of the invention has a extremely high specific initial permeability as compared with the conventional nanocrystalline alloy, and is suitable for use in magnetic core of transformers, choke coils, etc.Type: GrantFiled: July 19, 1995Date of Patent: March 18, 1997Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Yoshio Bizen, Shin Nakajima, Shunsuke Arakawa
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Patent number: 5591276Abstract: There is provided according to the present invention a magnetic alloy with ultrafine crystal grains having a composition represented by the general formula:Fe.sub.100-x-y M.sub.x B.sub.y (atomic %)wherein M represents at least one element selected from Ti, Zr, Hf, V, Nb, Mo, Ta, Cr, W and Mn, 4.ltoreq.x.ltoreq.15, 2.ltoreq.y.ltoreq.25, and 7.ltoreq.x+y.ltoreq.35, at least 50% of the alloy structure being occupied by crystal grains having an average grain size of 500 .ANG. or less, and the crystal grains being based on a bcc structure. It may further contain X (Si, Ge, P, Ga, etc.) and/or T (Au, Co, Ni, etc.). This magnetic alloy has an excellent saturation magnetic flux density, permeability and heat resistance.Type: GrantFiled: November 19, 1993Date of Patent: January 7, 1997Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Yoshio Bizen, Shigekazu Suwabe, Kiyotaka Yamauchi, Toshikazu Nishiyama
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Patent number: 5567537Abstract: A magnetic core element for use in a thin antenna. The magnetic core element has a thickness of 25 .mu.m or less and is made of a particular amorphous alloy strip or a particular nano-crystalline alloy strip. A thin antenna having a laminated magnetic core made of the magnetic core elements is highly resistant to deformation and has a high Q-value.Type: GrantFiled: April 11, 1995Date of Patent: October 22, 1996Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Shunsuke Arakawa
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Patent number: 5160379Abstract: An Fe-base soft magnetic alloy having the composition represented by the general formula:(Fe.sub.1-a M.sub.a).sub.100-x-y-z-.alpha.-.beta.-.gamma. Cu.sub.x Si.sub.y B.sub.z M'.sub..alpha. M".sub..beta. X.sub..gamma.wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M" is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z, .alpha., .beta. and .gamma. respectively satisfy 0.ltoreq.a.ltoreq.0.5, 0.1.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.30, 0.ltoreq.z.ltoreq.25, 5.ltoreq.y+z.ltoreq.30, 0.1.ltoreq..alpha..ltoreq.30, .beta..ltoreq.10 and .gamma..ltoreq.10, at least 50% of the alloy structure being fine crystalline particles having an average particle size 1000 .ANG. or less.Type: GrantFiled: January 22, 1991Date of Patent: November 3, 1992Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi, Shigeru Oguma
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Patent number: 5151137Abstract: A magnetic alloy with ultrafine crystal grains having a composition represented by the general formula:Co.sub.100.sub.-x-y-z-a-b Fe.sub.a M.sub.x B.sub.y X.sub.z T.sub.b (atomic %)wherein M represents at least one element selected from Ti, Zr, Hf, V, Nb, Mo, Ta, Cr, W and Mn, X represents at least one element selected from Si, Ge, P, Ga, Al and N, T represents at least one element selected from Cu, Ag, Au, platinum group elements, Ni, Sn, Be, Mg, Ca, Sr and Ba, 0<a.ltoreq.30, 2.ltoreq.x.ltoreq.15, 10.ltoreq.y.ltoreq.25, 0.ltoreq.z.ltoreq.10, 0<b.ltoreq.10, and 12<x+y+z+b.ltoreq.35. Such a magnetic alloy can be produced by producing an amorphous alloy having the above composition, and subjecting the resulting amorphous alloy to a heat treatment to cause crystallization, thereby providing the resulting alloy having a structure, at least 50% of which is occupied by crystal grains having an average grain size of 500 .ANG. or less.Type: GrantFiled: November 16, 1990Date of Patent: September 29, 1992Assignee: Hitachi Metals Ltd.Inventors: Yoshihito Yoshizawa, Yoshio Bizen, Kiyotaka Yamauchi, Toshikazu Nishiyama, Shigekazu Suwabe
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Patent number: 5114503Abstract: A magnetic core comprised of an amorphous alloy ribbon wound into a toroidal shape, wherein the said amorphous alloy has a composition of the formula:(Co.sub.1-x-y-z Fe.sub.x Ni.sub.y Mn.sub.z).sub.100-a-b-c M.sub.a Si.sub.b B.sub.cwherein M is at least one element selected from the group consisting of Nb, Cr and Mo, and x, y, z, a, b and c are numbers which satisfy relations of 0<a.ltoreq.6, 13.ltoreq.b.ltoreq.16, 7.ltoreq.b.ltoreq.10, 0<x.ltoreq.0.1, 0.ltoreq.y.ltoreq.0.2 and 0.ltoreq.x.ltoreq.0.13 respectively, said amorphous alloy after heat treatment having a rectangular ratio Br/Bs of at least 80%, a Bs value in a range of 5 KG to 8 KG and a stress relief ratio of at least 75%.Type: GrantFiled: March 24, 1987Date of Patent: May 19, 1992Assignee: Hitachi Metals, Inc.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi
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Patent number: 5069731Abstract: A low-frequency transformer including a magnetic core made of an alloy having the composition represented by the general formula:(Fe.sub.1-a M.sub.a).sub.100-x-y-z-.alpha. Cu.sub.x Si.sub.y B.sub.z M'.sub..alpha. (atomic %)wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Mo, Zr, Hf and Ti, and a, x, y, z and .alpha. respectively satisfy 0.ltoreq.a.ltoreq.0.3, 0.1.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.17, 4.ltoreq.z.ltoreq.17, 10.ltoreq.y+z.ltoreq.28 and 0.1.ltoreq..alpha..ltoreq.5, at least 50% of the alloy structure being occupied by fine crystal grains having an average grain size of 1000 .ANG. or less when measured by their maximum diameters. The alloy may further contain at least one element selected from the group consisting of Ge, P, C, Ga, Al and N.Type: GrantFiled: March 23, 1989Date of Patent: December 3, 1991Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi
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Patent number: 4985089Abstract: Fe-base soft magnetic alloy powder and dust core having the composition represented by the general formula:(Fe.sub.1-a M.sub.a).sub.100-x-y-z-.alpha.-.beta.-.gamma. Cu.sub.x Si.sub.y B.sub.z M'.sub..alpha. M".sub..beta. X.sub..gamma.wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M" is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z, .alpha., .beta. and .gamma. respectively satisfy 0.ltoreq.a.ltoreq.0.5, 0.1.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.30, 0.ltoreq.z.ltoreq.25, 0.ltoreq.y+z.ltoreq.35, 0.1.ltoreq..alpha..ltoreq.30, 0.ltoreq..beta..ltoreq.10 and 0.ltoreq..gamma..ltoreq.10, at least 50% of the alloy structure being fine crystalline particles having an average particle size of 500 .ANG. or less.Type: GrantFiled: July 25, 1988Date of Patent: January 15, 1991Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi
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Patent number: 4945339Abstract: An anti-theft sensor marker is disclosed which has good sensitivity characteristics and which does not readily deteriorate due to bending stress. The marker is mainly composed of an alloy ribbon and is employed in an anti-theft system in which the stealing of a commodity previously marked by the marker is determined by detecting a magnetic field of a specific frequency with respect to an incident magnetic field intensity applied to a detection region through the alloy ribbon of the marker when the marker is disposed within the detection region.Type: GrantFiled: November 16, 1988Date of Patent: July 31, 1990Assignee: Hitachi Metals, Ltd.Inventors: Kiyotaka Yamauchi, Yoshihito Yoshizawa
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Patent number: 4918555Abstract: A magnetic head having at least one magnetic gap in its magnetic path, which comprises an Fe-base solf magnetic alloy layer in the magnetic path, at least 50% of the structure of said alloy layer consisting of fine crystalline particles having a body-centered cubic structure and an average particle size of 500 .ANG. or less.Type: GrantFiled: July 25, 1988Date of Patent: April 17, 1990Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi, Toshikazu Nishiyama, Shigekazu Suwabe
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Patent number: 4881989Abstract: An Fe-base soft magnetic alloy having the composition represented by the general formula:(Fe.sub.1-a M.sub.a).sub.100-x-y-z-.alpha.-.beta.-.gamma. Cu.sub.x Si.sub.y B.sub.z M'.sub.60 M".sub..beta. X.sub..gamma.wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M" is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z, .alpha., .beta. and .gamma. respectively satisfy 0.ltoreq.a.ltoreq.0.5, 0.1.ltoreq.x.ltoreq.3, 0.ltoreq.y.ltoreq.30, 0.ltoreq.z.ltoreq.25, 5.ltoreq.y+z.ltoreq.30, 0.1.ltoreq..alpha..ltoreq.30, .beta..ltoreq.10 and .gamma..ltoreq.10, at least 50% of the alloy structure being fine crystalline particles having an average particle size of 1000 .ANG. or less.Type: GrantFiled: October 1, 1987Date of Patent: November 21, 1989Assignee: Hitachi Metals, Ltd.Inventors: Yoshihito Yoshizawa, Kiyotaka Yamauchi, Shigeru Oguma
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Patent number: 4871925Abstract: A high-voltage pulse generating apparatus having at least one magnetic switch comprising a magnetic core constituted by an Fe-base soft magnetic alloy ribbon wound in a toroidal form, the alloy having the composition represented by the general formula: ##STR1## wherein M is Co and/or Ni, M' is at least one element selected from the group consisting of Nb, W, Ta, Zr, Hf, Ti and Mo, M" is at least one element selected from the group consisting of V, Cr, Mn, Al, elements in the platinum group, Sc, Y, rare earth elements, Au, Zn, Sn and Re, X is at least one element selected from the group consisting of C, Ge, P, Ga, Sb, In, Be and As, and a, x, y, z, .alpha., .beta. and .gamma. respectively satisfy 0.ltoreq.a.ltoreq.0.5, 0.1.ltoreq.x.ltoreq.3, 6.ltoreq.y.ltoreq.25, 3.ltoreq.z.ltoreq.15, 14.ltoreq.y+z.ltoreq.30, 1.ltoreq..alpha..ltoreq.10, 0.ltoreq..beta..ltoreq.10 and 0.ltoreq..gamma..ltoreq.Type: GrantFiled: October 24, 1988Date of Patent: October 3, 1989Assignee: Hitachi Metals, Ltd.Inventors: Kiyotaka Yamauchi, Yoshihito Yoshizawa, Shin Nakajima
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Patent number: 4769091Abstract: A magnetic core comprised of an amorphous metal alloy having a composition represented by the formula:(Co.sub.1-a-b-c Fe.sub.a Mn.sub.b Mo.sub.c).sub.100-x-y Si.sub.x B.sub.y (in atomic %)wherein a, b, c, x and y are numbers which respectively satisfy relations 0.ltoreq.a.ltoreq.0.05, 0.03.ltoreq.b.ltoreq.0.08, 0.01.ltoreq.c.ltoreq.0.04, 0.04.ltoreq.b+c.ltoreq.0.10, 14.ltoreq.x.ltoreq.16 and 7.5.ltoreq.y.ltoreq.9.5, and the core is treated by a process including a step to keep the core at least one time at a temperature between 0.95.times.Tc and 150.degree. C. for a time of one hour to ten hours in a magnetic field, the direction of which is generally coincidental with the direction of the magnetic path in the core.Type: GrantFiled: August 10, 1987Date of Patent: September 6, 1988Assignee: Hitachi Metals Ltd.Inventors: Yoshihito Yoshizawa, Shin Nakajima, Kiyotaka Yamauchi
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Patent number: 4757219Abstract: A lamination type of magnetostrictor incorporated with a mass of plural plates of amorphous metal alloy material laminated by means of a binder wherein the thickness of the plates is equal to or more than 80 .mu.m and the space factor of amorphous metal alloy in the mass is equal to or more than 80% and a manufacturing method thereof.Type: GrantFiled: January 30, 1986Date of Patent: July 12, 1988Assignees: Hitachi Metals, Ltd., Hitachi Ltd.Inventors: Kiyotaka Yamauchi, Yoshihito Yoshizawa, Kiyoshi Koyano