Patents by Inventor Hiroyuki Mitani

Hiroyuki Mitani 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).

  • Patent number: 10923257
    Abstract: 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.
    Type: Grant
    Filed: April 27, 2016
    Date of Patent: February 16, 2021
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Mitani, Hirofumi Hojo, Yuji Taniguchi, Satomi Sato
  • Patent number: 10256019
    Abstract: 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 cm?1 to 2500 cm?1 is 0.04 or more being indicated by absorbance when the coating film is analyzed by infrared diffuse reflectance spectroscopy.
    Type: Grant
    Filed: August 5, 2015
    Date of Patent: April 9, 2019
    Assignee: KOBE STEEL, LTD.
    Inventors: Takeshi Ohwaki, Hiroyuki Mitani, Hirofumi Hojo, Kasumi Yanagisawa, Nobuaki Akagi
  • Patent number: 10063114
    Abstract: Provided is a so-called Lundell-type generator capable of avoiding generation of eddy current in rotor iron-cores without complicated structure. The generator includes a stator, a rotary shaft, first and second rotor iron-cores, and a rotor coil. Each rotor iron-core includes a base and rotor magnetic-pole portions extending axially from the base, the rotor coil disposed on the inside thereof. Each rotor iron-core is formed of a plurality of unit plates stacked axially. The unit plates integrally include respective basal plate portions stacked to form the bases and a plurality of magnetic-pole plate portions stacked to form the rotor magnetic-pole plate portions stacked to form the rotor magnetic-pole portions.
    Type: Grant
    Filed: March 31, 2014
    Date of Patent: August 28, 2018
    Assignee: Kobe Steel, Ltd.
    Inventors: Kenichi Inoue, Hideo Fujii, Hiroyuki Mitani, Takehiro Tsuchida, Katsura Kajihara
  • Publication number: 20180182520
    Abstract: 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.
    Type: Application
    Filed: April 27, 2016
    Publication date: June 28, 2018
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hiroyuki MITANI, Hirofumi HOJO, Yuji TANIGUCHI, Satomi SATO
  • Patent number: 9818519
    Abstract: Provided is soft magnetic powder used to manufacture a dust core having good mechanical strength and superior formability while iron loss is reduced. The soft magnetic powder for dust cores according to the invention is soft magnetic mixed powder that includes pure iron powder and soft magnetic iron-base alloy powder, wherein the proportion of the soft magnetic iron-base alloy powder in the mixture is 5 to 60 mass %, the ratio of the modes of the particle size distributions of the soft magnetic iron-base alloy powder and the pure iron powder ((the mode of the particle size distribution of the soft magnetic iron-base alloy powder)/(the mode of the particle size distribution of the pure iron powder)) is 0.9 or more and less than 5, and the ratio Rover/Runder is 1.
    Type: Grant
    Filed: September 19, 2013
    Date of Patent: November 14, 2017
    Assignee: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takeo Miyamura, Hiroyuki Mitani
  • Patent number: 9589712
    Abstract: 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 ?m or more and has an interface density of more than 0 ?m?1 and less than or equal to 2.6×10?2 ?m?1, where the interface density is determined from a cross-sectional area (?m2) and a cross-sectional circumference (?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.
    Type: Grant
    Filed: December 10, 2012
    Date of Patent: March 7, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Takeo Miyamura, Hiroyuki Mitani, Hirofumi Hojo
  • Patent number: 9583261
    Abstract: 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 ?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%.
    Type: Grant
    Filed: August 26, 2013
    Date of Patent: February 28, 2017
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Mitani, Takeo Miyamura, Hirofumi Hojo, Tomotsuna Kamijo
  • Publication number: 20160141922
    Abstract: Provided is a so-called Lundell-type generator capable of avoiding generation of eddy current in rotor iron-cores without complicated structure. The generator includes a stator, a rotary shaft, first and second rotor iron-cores, and a rotor coil. Each rotor iron-core includes a base and rotor magnetic-pole portions extending axially from the base, the rotor coil disposed on the inside thereof. Each rotor iron-core is formed of a plurality of unit plates stacked axially. The unit plates integrally include respective basal plate portions stacked to form the bases and a plurality of magnetic—pole plate portions stacked to form the rotor magnetic-pole plate portions stacked to form the rotor magnetic-pole portions.
    Type: Application
    Filed: March 31, 2014
    Publication date: May 19, 2016
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Kenichi INOUE, Hideo FUJII, Hiroyuki MITANI, Takehiro TSUCHIDA, Katsura KAJIHARA
  • Patent number: 9275779
    Abstract: 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 ?m is 1×104 pieces/mm2 or less and the number of inclusions having an equivalent circle diameter exceeding 3 ?m is 10 pieces/mm2 or less.
    Type: Grant
    Filed: November 29, 2011
    Date of Patent: March 1, 2016
    Assignee: Kobe Steel, Ltd.
    Inventors: Hirofumi Hojo, Masamichi Chiba, Hiroyuki Mitani, Nobuaki Akagi, Tomotsuna Kamijo
  • Publication number: 20150340138
    Abstract: 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 cm?1 to 2500 cm?1 is 0.04 or more being indicated by absorbance when the coating film is analyzed by infrared diffuse reflectance spectroscopy.
    Type: Application
    Filed: August 5, 2015
    Publication date: November 26, 2015
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (KOBE STEEL, LTD.)
    Inventors: Takeshi OHWAKI, Hiroyuki MITANI, Hirofumi HOJO, Kasumi YANAGISAWA, Nobuaki AKAGI
  • Patent number: 9160219
    Abstract: Disclosed is a brushless motor (1A) which is an axial gap type brushless motor (1A) wherein stators (3A, 4A) comprising a coil (41) and a rotor (2) comprising a permanent magnet (23) are arranged with a gap therebetween in the axial direction. The coil (41) is a band-like wire which is spirally wound such that the width direction of the band-like wire generally coincides with the direction of the magnetic flux that is generated by the permanent magnet (23) of the rotor (2). Consequently, the axial gap type brushless motor (1A) having the above-described structure can be further reduced in eddy current loss in comparison to conventional brushless motors.
    Type: Grant
    Filed: December 6, 2010
    Date of Patent: October 13, 2015
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Takamatsu, Koji Inoue, Kenichi Inoue, Takashi Hase, Osamu Ozaki, Chikara Ichihara, Masakatsu Maruyama, Yasushi Maeda, Hiroyuki Mitani
  • Publication number: 20150243420
    Abstract: Provided is soft magnetic powder used to manufacture a dust core having good mechanical strength and superior formability while iron loss is reduced. The soft magnetic powder for dust cores according to the invention is soft magnetic mixed powder that includes pure iron powder and soft magnetic iron-base alloy powder, wherein the proportion of the soft magnetic iron-base alloy powder in the mixture is 5 to 60 mass %, the ratio of the modes of the particle size distributions of the soft magnetic iron-base alloy powder and the pure iron powder ((the mode of the particle size distribution of the soft magnetic iron-base alloy powder)/(the mode of the particle size distribution of the pure iron powder)) is 0.9 or more and less than 5, and the ratio Rover/Runder is 1.
    Type: Application
    Filed: September 19, 2013
    Publication date: August 27, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Takeo Miyamura, Hiroyuki Mitani
  • Publication number: 20150187493
    Abstract: 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 ?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%.
    Type: Application
    Filed: August 26, 2013
    Publication date: July 2, 2015
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hiroyuki Mitani, Takeo Miyamura, Hirofumi Hojo, Tomotsuna Kamijo
  • Patent number: 9071118
    Abstract: 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.
    Type: Grant
    Filed: June 17, 2010
    Date of Patent: June 30, 2015
    Assignees: NATIONAL UNIVERSITY CORPORATION HOKKAIDO UNIVERSITY, KABUSHIKI KAISHA KOBE SEIKO SHO
    Inventors: Masatsugu Takemoto, Hiroyuki Mitani, Hirofumi Hojo, Koji Inoue, Osamu Ozaki
  • Publication number: 20140002219
    Abstract: This invention addresses the problem of providing an iron base soft magnetic powder for a powder magnetic core that does not use rare metals, that can maintain the electrical insulating properties between the iron powder particles even when subjected to high temperature thermal processing, and that has excellent thermal stability and mechanical strength. This invention also addresses the problem of providing a fabrication method for the iron base soft magnetic powder for the powder magnetic core, and providing the powder magnetic core. In this iron base soft magnetic powder for the powder magnetic core, a phosphatized coating film is formed on the surface of the iron base soft magnetic powder, and a silicon resin coating film is formed on the surface of the phosphatized coating film. The phosphatized coating film contains P, B, Mg, and Al.
    Type: Application
    Filed: March 11, 2011
    Publication date: January 2, 2014
    Applicant: Kabushiki Kaisha Kobe Seiko Sho (Kobe Steel, Ltd.)
    Inventors: Hiroyuki Mitani, Takeshi Ohwaki, Hirofumi Hojo, Satoshi Nishida, Yuji Taniguchi
  • Patent number: 8614617
    Abstract: 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 (D1) 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 ((L1?L2)/L3) that has had: the difference (L1?L2) between; the space interval (L1) between an inner wall face of a first core member (3) and an inner wall face of a second core member (4), at the innermost circumference position of the air-core coil (1); and the space (L2) between the inner wall face of the first core member (3) and the inner wall face of the second core member (4), at the outermost circumference position of the air-core coil (1); divided by an average value (L3); configured to be 1/50 or less.
    Type: Grant
    Filed: July 16, 2010
    Date of Patent: December 24, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Mitani, Kyoji Zaitsu, Kenichi Inoue, Osamu Ozaki, Hiroshi Hashimoto, Hirofumi Hojo, Koji Inoue, Eiichiro Yoshikawa, Naoya Fujiwara
  • Publication number: 20130200744
    Abstract: This brushless DC motor (1) is provided with a stator (3) having a main body (312, 322) disposed on both ends thereof in the rotational axis direction with a single exciting coil (2) disposed between the main bodies (312, 322), and with a rotor (4) disposed in the interior of the stator (3), wherein main body (312) is formed with a first magnetic core (31) and main body (322) is formed with a second magnetic core (32), the magnetic cores (31, 32) functioning as a magnetic pole and having protrusions (311, 321), the quantity of which being different for each magnetic core (31, 32). The brushless DC motor (1) uses, as the driving force, the variation in the magnetic resistance between the stator (3) and the rotor (4) in relation to the flow of the magnetic flux generated in the periphery of the exciting coil (2).
    Type: Application
    Filed: October 4, 2011
    Publication date: August 8, 2013
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Takeo Miyamura, Kenichi Inoue, Akira Tsutsui, Hiroshi Hashimoto, Hiroyuki Mitani, Kyoji Zaitsu
  • Patent number: 8445105
    Abstract: An iron-based magnetic powder for dust cores has layers of phosphoric acid-based film and silicone resin film sequentially formed on the surface thereof. The phosphoric acid-based film contains at least one element selected from the group consisting of Co, Na, S, Si, and W. The iron-based powder effectively keeps insulation among iron powder particles, excels in mechanical strength even though the amount of insulating material is reduced due to achieve high-density forming, and exhibits good thermal stability necessary for electrical insulating properties even after high-temperature heat treatment.
    Type: Grant
    Filed: August 2, 2007
    Date of Patent: May 21, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Mitani, Nobuaki Akagi, Hirofumi Houjou, Chio Ishihara, Makoto Iwakiri, Sohei Yamada, Yasukumi Mochimizo
  • Patent number: 8409707
    Abstract: The invention relates to an iron-based soft magnetic powder for a dust core, wherein a film comprising Fe and Co, a phosphoric acid-based chemical conversion film and a silicone resin film are formed in this order on the surface of an iron-based soft magnetic powder, and to a dust core obtained by molding the iron-based soft magnetic powder for a dust core. The invention also relates to an iron-based soft magnetic powder for a dust core formed by coating the surface of an iron-based soft magnetic powder with an insulating film, wherein the powder has a particle diameter of from 45 ?m to 180 ?m, the insulating film is composed of two layers in which a lower layer composed of a phosphoric acid-based chemical conversion film and an upper layer composed of a silicone resin film, and each of the films has a thickness of from 100 nm to 280 nm, and to a dust core obtained by molding the iron-based soft magnetic powder for a dust core.
    Type: Grant
    Filed: July 2, 2008
    Date of Patent: April 2, 2013
    Assignee: Kobe Steel, Ltd.
    Inventors: Hiroyuki Mitani, Nobuaki Akagi, Hirofumi Houjou
  • Publication number: 20130009508
    Abstract: Disclosed is a brushless motor (1A) which is an axial gap type brushless motor (1A) wherein stators (3A, 4A) comprising a coil (41) and a rotor (2) comprising a permanent magnet (23) are arranged with a gap therebetween in the axial direction. The coil (41) is a band-like wire which is spirally wound such that the width direction of the band-like wire generally coincides with the direction of the magnetic flux that is generated by the permanent magnet (23) of the rotor (2). Consequently, the axial gap type brushless motor (1A) having the above-described structure can be further reduced in eddy current loss in comparison to conventional brushless motors.
    Type: Application
    Filed: December 6, 2010
    Publication date: January 10, 2013
    Applicant: KABUSHIKI KAISHA KOBE SEIKO SHO (Kobe Steel, Ltd.)
    Inventors: Hiroyuki Takamatsu, Koji Inoue, Kenichi Inoue, Takashi Hase, Osamu Ozaki, Chikara Ichihara, Masakatsu Maruyama, Yasushi Maeda, Hiroyuki Mitani