Tdk Corporation

Okuyama International Patent Office

Hideharu Moro

Tsuneo Suzuki

Tsutomu Chou

Junetsu Tamura

Atsushi Sato

Yoshihiro Maeda

Takashi Yamada

Tomokazu Ito

Hitoshi Ohkubo

Makoto Orikasa

Takeo Tsukada

Akihiro Harada

Manabu Ohta

Makoto Morita

Yasuharu Miyauchi

Kyohei Tonoyama

Yuuya Kaname

Kazuhiko Shibata

Yasuhiko Kitajima

Hidetoshi Suzuki

Hiroshi Tomita

Toshiaki Yamada

Naoyoshi Sato

Takashi Nagasaka

Kyotaro Abe

Tetsuhito Yoneyama

Yoshikazu Narumiya

Toshiaki Kikuchi

Katsuhiko Wakayama

Masahito Koeda

Osamu Kohmoto

Yu Yonezawa

Masaaki Kanasugi

Yoshihito Hirai

Hideaki Sone

Atsuhito Matsukawa

Shohei Mimura

Norishige Yamaguchi

Kazuhiro Okada

Sadaki Satoh

Kesaharu Takatoh

Masami Endo

Atsushi Makimura

Koyu Enda

Jyunetsu Tamura

Sadaki Sato

Hideki Kitashima

Shigeo Satoh

Haruyuki Takahashi

Naoki Kawakubo

Toshihisa Murayoshi

The object of the present invention is to provide a fluidizing particle capable of improving a fluidity of a magnetic particle for a magnetic core and capable of improving a permeability of the magnetic core. The fluidizing particle includes a particle body having a magnetic property and a coating layer including a silicon compound covering the particle body, wherein a particle size of the fluidizing particle is 10 to 40 nm, and a circularity of the fluidizing particle is 0.55 or more.

Fluidizing particle and magnetic core

A dust core includes large particles having an average particle size of 8-15 &#x3bc;m, medium particles having an average particle size of 1-5 &#x3bc;m, and small particles having an average particle size of 300-900 nm when a cross section thereof is observed. An area ratio occupied by the large particles is 50% to 90%, an area ratio occupied by the medium particles is 0% to 30%, and an area ratio occupied by the small particles is 5% to 30%, when a total area ratio occupied by the large particles, the medium particles and the small particles is 100% in the cross section. Vickers hardness (Hv) of the large particles, the medium particles and the small particles is 150-600 respectively. The small particles are alloy powder containing Fe and at least Si or N. The dust core may be included in an inductor element.

Dust core and inductor element

A noise suppression sheet comprises at least one composite layer, the composite layer including: an insulating resin layer; a non-magnetic metal layer formed on the insulating resin layer; and a metal magnetic layer formed on the non-magnetic metal layer, and the composite layer has a through hole. When the noise suppression sheet comprises a plurality of composite layers, the through holes are misaligned in adjacent composite layers in the laminating direction.

Noise suppression sheet

A noise suppression sheet comprises a non-magnetic metal layer, a plurality of metal magnetic layers, and a plurality of insulating layers, and the metal magnetic layer and the insulating layer are alternately laminated on the non-magnetic metal layer. The noise suppression sheet can absorb and suppress noise generated from a circuit or the like in an electronic component by being mounted on the electronic component or the like. In the noise suppression sheet, noise is absorbed by each of the metal magnetic layers. Noise that is transmitted without being absorbed by the metal magnetic layer can be reflected by the non-magnetic metal layer and can be absorbed again by the metal magnetic layer, and hence the noise suppression sheet can suppress noise effectively.

A dust core excellent in DC superimposition characteristics and low in eddy current loss at a high frequency band of several MHz, and an inductor element using the dust core. A dust core contains large and small particles of insulated soft magnetic material powder, wherein the large and small particles have a saturation magnetic flux density of 1.4 T or more, and wherein in the soft magnetic material powder observed in a cross section of the dust core, a ratio of an area occupied by large particles to an area occupied by small particles in the cross section is 9:1 to 5:5, when a group of particles having particle size of 3 &#x3bc;m or more and 15 &#x3bc;m or less is defined as the large particles, and group of particles having a particle size of 300 nm or more and 900 nm or less is defined as the small particles.

In a planar coil element and a method for producing the same, a metal magnetic powder-containing resin containing an oblate or needle-like first metal magnetic powder contains a second metal magnetic powder having an average particle size (1 &#x3bc;m) smaller than that (32 &#x3bc;m) of the first metal magnetic powder, which significantly reduces the viscosity of the metal magnetic powder-containing resin. Therefore, the metal magnetic powder-containing resin is easy to handle when applied to enclose a coil unit, which makes it easy to produce the planar coil element.

Planar coil element and method for producing the same

In a planar coil element, the quantitative ratio of inclined particles to total particles of a first metal magnetic powder contained in a metal magnetic powder-containing resin provided in a through hole of a coil unit is higher than the quantitative ratio of inclined particles to total particles of the first metal magnetic powder contained in the metal magnetic powder-containing resin provided in other than the through hole, and many of particles of the first metal magnetic powder in the magnetic core are inclined particles whose major axes are inclined with respect to the thickness direction and the planar direction of a substrate. Therefore, the planar coil element has improved strength as compared to a planar coil element shown in FIG.A and has improved magnetic permeability as compared to a planar coil element shown in FIG.B.

Planar coil element

A soft magnetic alloy powder containing Fe&#x2014;Ni-based crystal particles is provided as one capable of adequately reducing core loss of a powder magnetic core and achieving satisfactory magnetic characteristics at an effective operating temperature of an element. The present invention provides a soft magnetic alloy powder containing Fe&#x2014;Ni-based crystal particles containing 45 to 55 mass % Fe and 45 to 55 mass % Ni, relative to a total mass of Fe and Ni, and containing 1 to 12 mass % Co and 1.2 to 6.5 mass % Si, relative to a total mass of Fe, Ni, Co, and Si.

Soft magnetic alloy powder, compact, and inductance element

A method for manufacturing a coil-embedded dust core with a small variation in inductance value with efficiency includes a step (a) of charging soft magnetic metal powder including an insulating material, composing a green body, so as to cover a coil, and (b) compacting the soft magnetic metal powder covering the coilin an axial direction of the coil. In the step (b), the soft magnetic metal powder is compacted while an amount of the soft metal powder charged into the part corresponding to the winding section is kept smaller than an amount of the soft magnetic metal powder charged into the other part that are not corresponding to the winding section, with an upper surface or a lower surface of the winding section as a reference.

Method for manufacturing inductor having coil embedded dust core

A dust core consists essentially of ferromagnetic powder; and an insulating binder, in which the ferromagnetic powder is dispersed; wherein the insulating binder is a silicone resin comprising a trifunctional alkyl-phenyl silicone resin and optionally containing an inorganic insulator such as an inorganic oxide, carbide or nitride. Preferably the alkyl-phenyl silicone resin is a methyl-phenyl silicone resin and comprises about 20 to 70 mol % of trifunctional groups. The dust core can be produced by pressure-molding a ferromagnetic powder, a lubricant and a trifunctional alkyl-phenyl silicone resin binder and heat treating the molded core at a temperature in the range of about 300 to about 800&#xb0; C. for a time period in the range of about 20 minutes to about 2 hours in a non-oxidizing atmosphere. The dust core has high magnetic permeability representing the direct current superimposition characteristics, has reduced core loss and has increased mechanical strength.

Dust core

A coil-embedded dust core and a method for manufacturing the coil-embedded dust core are provided. The coil-embedded dust core comprises a coil formed from a flat conductor wound in a coil configuration, and a green body consisting of insulating material-coated ferromagnetic metal particles. This results in a coil-embedded dust core more compact in size but with larger inductance. A rectangular wire can be used as the flat conductor. In addition, parts of the coil may function as terminal sections. In this case, the terminal sections of the coil may be formed wider than other part of the coil. The coil-embedded dust core is less prone to joint failures between a coil and terminal sections and to insulation failures of the coil and the terminal section with respect to the magnetic powder. The coil-embedded dust core is more compact while achieving larger inductance.

Coil-embedded dust core and method for manufacturing the same

A dust core consists essentially of ferromagnetic powder; and an insulating binder, in which the ferromagnetic powder is dispersed; wherein the insulating binder is a silicone resin comprising a trifunctional alkyl-phenyl silicone resin and optionally containing an inorganic insulator such as an inorganic oxide, carbide or nitride. Preferably the alkyl-phenyl silicone resin is a methyl-phenyl silicone resin and comprises about 20 to 70 mol % of trifunctional groups. The dust core can be produced by pressure-molding a ferromagnetic powder, a lubricant and a trifunctional alkyl-phenyl silicone resin binder and heat treating the molded core at a temperature in the range of about 300 to about 800 &#xb0; C. for a time period in the range of about 20 minutes to about 2 hours in a non-oxidizing atmosphere. The dust core has high magnetic permeability representing the direct current superimposition characteristics, has reduced core loss and has increased mechanical strength.

There are provided a coil-embedded dust core that provides high inductance and a method for manufacturing the same. The coil-embedded dust core includes a coilformed by winding a flat conductorand a green bodycomprising of ferromagnetic metal powder coated with an insulating material. The coilis composed of a winding sectionin which the flat conductorhaving front and back surfaces opposed to each other with a predetermined distance is wound and lead-out end sectionsandthat are extended from the winding section. Either one of the front and back surfaces of the lead-out end sectionand either one of the front and back surfaces of the lead-out end sectionare formed so as to be on the same plane. By using the coilin which the both end sections (lead-out end sectionsand) are formed on the same plane, the coil-embedded dust core can be made smaller in size, and high inductance can be provided.

Coil-embedded dust core and method for manufacturing the same, and coil and method for manufacturing the same

The invention provides a process for producing a coil-embedded dust core by embedding a coil in magnetic powders comprising ferromagnetic metal particles coated with an insulating material. At the first compression molding step one portion of magnetic powders is filled in a molding die and then compression molded to form a lower core. At a coil positioning step the coil is positioned on the upper surface of the lower core in the molding die. At a coil embedding step another portion of magnetic powders is again filled in the molding die in such a way that the coil is embedded in these magnetic powders. At the second compression molding step pressure is applied to the lower core and coil in the direction of lamination thereof.

Coil-embedded dust core production process, and coil-embedded dust core formed by the production process

Growing community of inventors

Tokyo, Japan

Hideharu Moro