Kobe Steel, Ltd.

Kabushiki Kaisha Kobe Seiko Sho

Hokkaido University

Hirofumi Hojo

Koji Inoue

Hiroyuki Mitani

Tomotsuna Kamijo

Takeshi Ohwaki

Wataru Urushihara

Nobuaki Akagi

Mamoru Hosokawa

Takeo Miyamura

Osamu Ozaki

Kenichi Inoue

Mikako Takeda

Hiroshi Hashimoto

Masamichi Chiba

Kyoji Zaitsu

Eiichiro Yoshikawa

Naoya Fujiwara

Masatsugu Takemoto

Yuji Taniguchi

Kasumi Yanagisawa

Satomi Sato

Satoshi Nishida

The present invention pertains to: a powder mixture for powder magnetic core obtained by mixing a lubricant, a solid lubricant, and a soft magnetic powder coated with an insulating coating, wherein a lubricant content is 0.1% by mass or more and 0.8% by mass and a solid lubricant content is 0.01% by mass or more and 0.2% by mass or less; and a powder magnetic core in which the powder mixture is used.

Powder mixture for powder magnetic core, and powder magnetic core

An iron-based soft magnetic powder for dust core having a high magnetic flux density, maintaining high electric insulation even after annealing, and more excellent in the mechanical strength in which a coating film having a phosphate conversion coating film is formed on the surface thereof and the peak height for the absorption of hydroxyl groups formed at 3700 cmto 2500 cmis 0.04 or more being indicated by absorbance when the coating film is analyzed by infrared diffuse reflectance spectroscopy.

Iron-based soft magnetic powder for dust core, method for manufacturing the same, and dust core

A powder for a powder magnetic core, being composed of iron-base soft magnetic powder particles which each have a phosphoric acid-based chemical conversion coating on the surface. In this powder, the maximum thickness of the phosphoric acid-based chemical conversion coating is 20 to 200 nm, and recessed portions are formed on the surface of the chemical conversion coating with the total area of openings of the recessed portions being 0.5 to 50% by area relative to the total area of the observation visual fields, as determined by observing ten or more parts of the surface of the phosphoric acid-based chemical conversion coating through a scanning electron microscope with a magnification of 10000&#xd7; or more.

Powder for powder magnetic core, and powder magnetic core

Disclosed is an iron-based soft magnetic powder obtained by preparing an iron-oxide-based soft magnetic powder through water atomization, and thermally reducing the iron-oxide-based soft magnetic powder. The iron-based soft magnetic powder has an average particle size of 100 &#x3bc;m or more and has an interface density of more than 0 &#x3bc;mand less than or equal to 2.6&#xd7;10&#x3bc;m, where the interface density is determined from a cross-sectional area (&#x3bc;m) and a cross-sectional circumference (&#x3bc;m) of the iron-based soft magnetic powder. The iron-based soft magnetic powder obtained by preparing an iron-oxide-based soft magnetic powder through water atomization and thermally reducing the iron-oxide-based soft magnetic powder, when used for the production of a dust core, can give a dust core having a low coercive force. Also disclosed is a duct core having a low coercive force and exhibiting superior magnetic properties.

Iron-based soft magnetic powder and production method thereof

A powder magnetic core which exhibits a high compact density and a reduced iron loss can be obtained by compacting a soft magnetic powder in which the mass ratio of soft magnetic powder particles that pass through a filter having an opening of 75 &#x3bc;m is 95 mass % or higher relative to the whole amount of the soft magnetic powder and which has a mean strain of less than 0.100%.

Iron powder for powder magnetic core and process for producing powder magnetic core

Disclosed is an iron-based soft magnetic powder for dust core use, which includes an iron-based soft magnetic matrix powder and a phosphate conversion coating on a surface of the matrix powder. The phosphate conversion coating contains nickel element and has an aluminum content of equal to or less than that in the matrix powder. The iron-based soft magnetic powder has such excellent heat resistance as to maintain electrical insulation at satisfactory level even after subjected to a high-temperature heat treatment.

Iron-based soft magnetic powder for dust core use, manufacturing method thereof, and dust core

Provided is an iron-based soft magnetic powder for dust core having a less coercive force, which is obtained by specifying the amount of inclusions in the iron-based powder for dust core, and at the same time, capable of decreasing the coercive force of a dust core produced using the iron-based soft magnetic powder. The iron-based soft magnetic powder for dust core is characterized by that when the cross-section of the iron-based soft magnetic powder particle is observed with a scanning electron microscope, the number of inclusions having an equivalent circle diameter from 0.1 to 3 &#x3bc;m is 1&#xd7;10pieces/mmor less and the number of inclusions having an equivalent circle diameter exceeding 3 &#x3bc;m is 10 pieces/mmor less.

Iron-based soft magnetic powder for dust core, preparation process thereof, and dust core

An axial motor includes a rotor arranged between a pair of stators with coils. In the rotor, a plurality of permanent magnets sandwiched between pairs of first magnetic materials and a plurality of second magnetic materials are alternately arranged in a rotation direction while gaps are provided therebetween. Since the permanent magnets are sandwiched by the first magnetic materials in the thus constructed axial motor, a field-weakening control can be performed. Since the second magnetic materials are provided, a reluctance torque can be generated. Further, since the gaps are provided, more magnetic fluxes generated from the permanent magnets can be caused to flow toward the coils. Therefore, the thus constructed axial motor can achieve a higher output, higher torque, higher efficiency, and miniaturization.

Axial motor

Provided is a reactor that enables high inductance to be generated with stability in a wide current range, while minimizing noise, processing cost, and eddy-current loss. The reactor (D) has the ratio (t/W) of the width (W) to the thickness (t) of a conductive member that composes an air-core coil configured to be 1 or less, and preferably, 1/10 or less. Furthermore, the reactor also has the absolute value of a value ((L&#x2212;L)/L) that has had: the difference (L&#x2212;L) between; the space interval (L) between an inner wall face of a first core member () and an inner wall face of a second core member (), at the innermost circumference position of the air-core coil (); and the space (L) between the inner wall face of the first core member () and the inner wall face of the second core member (), at the outermost circumference position of the air-core coil (); divided by an average value (L); configured to be 1/50 or less. The ratio (R/W) of the radius (R), from the axis-center (O) of the air-core coil () to the outer circumference of the air-core coil (), to the width (W) of the air-core coil () (conductive member), is 2=R/W=4.

Reactor

Provided is a dust core excellent in flux density, iron loss, and mechanical strength. A production process of a dust core according to the invention includes a step of compacting a mixture obtained by mixing an iron-based soft magnetic powder for powder compact having a phosphate conversion coating film on the surface of an iron-based soft magnetic powder with a lubricant to obtain a powder compact, a heat treatment step of heating the resulting powder compact at 550&#xb0; C. or more but not more than 650&#xb0; C. in an inert atmosphere, and a heat treatment step of heating the heat-treated powder compact at 420&#xb0; C. or more but not more than 530&#xb0; C. in an oxidizing atmosphere.

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Takasago, Japan

Hirofumi Hojo