Patents by Inventor Akihiro Daikoku

Akihiro Daikoku 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: 9825495
    Abstract: A rotating electric machine including a rotator including a small-angle rotator portion and a large-angle rotator portion respectively having different inter-magnet end angles, each being a plane angle formed between a line connecting one outermost peripheral-side end of a permanent magnet and an axial center of the rotator and a line connecting an outermost peripheral-side end of another permanent magnet and the axial center of the rotator. The rotator includes three layers of the small-angle rotator portion, the large-angle rotator portion, and the small-angle rotator portion, which are laminated in the stated order along an axial line of the rotator. Therefore, demagnetization due to a temperature rise of the permanent magnets is suppressed. In addition, a temperature distribution in the permanent magnets in the axial direction of the rotator is reduced.
    Type: Grant
    Filed: May 15, 2014
    Date of Patent: November 21, 2017
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Moriyuki Hazeyama, Akihiro Daikoku
  • Patent number: 9806589
    Abstract: A squirrel-cage rotor manufacturing method capable of suppressing, at the time of performing die-casting, formation of gaps between closing portions and a rotor core at radially outer parts of rotor slots, or generation of a thermal stress in the rotor core as a result of expansion of the closing portions. The squirrel-cage rotor manufacturing method includes: arranging, through die-casting, conductors into rotor slots that are formed along a radially outer part of a rotor core; and performing the die-casting under a state in which radially outer parts of the rotor slots are closed with closing portions made of the same material as a material of the rotor core.
    Type: Grant
    Filed: December 15, 2014
    Date of Patent: October 31, 2017
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Taiga Komatsu, Hideaki Arita, Akihiro Daikoku, Yoshihiro Miyama, Moriyuki Hazeyama
  • Patent number: 9755560
    Abstract: A multigroup, multiphase driving system includes a power converter that converts direct current power into alternating current power and vice versa, a direct current power supply connected to a direct current side of the power converter to be charged with and discharge direct current power, and a rotary electric machine connected to an alternating current side of the power converter and including a plurality of groups of multiphase armature windings, and further including a determination unit that determines the number of groups to be used to drive the rotary electric machine on the basis of a rotation speed of the rotary electric machine, a current flowing through the rotary electric machine, a direct current power supply voltage of the direct current power supply, and a carrier frequency of the power converter, the multigroup, multiphase driving system overall loss in the system can be reduced.
    Type: Grant
    Filed: May 27, 2015
    Date of Patent: September 5, 2017
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoshihiro Miyama, Moriyuki Hazeyama, Akihiro Daikoku
  • Patent number: 9722465
    Abstract: A tooth of a stator has a tapered shape in which a tooth width decreases toward a distal end portion thereof. A winding is formed of an edgewise winding wound around the tooth in a row. The winding is supplied with power so that a terminal on a base portion side of the tooth may have a higher voltage than that of a terminal on the distal end portion side thereof. A tooth width Th of the base portion is set within the range of Tmin<Th<1.25Tha defined by a tooth width Tha that maximizes an index using an outer radius and a core back width of a stator core, a clearance of the windings in the slot, a winding width, an air gap between the teeth and the winding, a pitch of the slot, and an inclination angle of the winding, and a permissible lower limit Tmin.
    Type: Grant
    Filed: June 4, 2013
    Date of Patent: August 1, 2017
    Assignee: Mitsubishi Electric Corporation
    Inventors: Moriyuki Hazeyama, Hideaki Arita, Yoshihiro Miyama, Akihiro Daikoku
  • Patent number: 9595851
    Abstract: Permanent magnets that form individual magnetic poles are configured by arranging three magnet blocks to be spaced apart from each other circumferentially, the three magnet blocks are each formed such that cross-sectional shapes that are perpendicular to a central axis of a rotor core are radially outwardly convex, and circumferential widths are narrower in magnet blocks that are further away from a magnetic pole center, and the three magnet blocks that are arranged circumferentially are formed to have mirror symmetry relative to a plane that passes through the magnetic pole center and the central axis of the rotor core.
    Type: Grant
    Filed: January 17, 2014
    Date of Patent: March 14, 2017
    Assignee: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Moriyuki Hazeyama, Takuma Sasai, Shinsuke Kayano, Masaya Inoue, Shinji Nishimura, Akihiro Daikoku
  • Publication number: 20170019050
    Abstract: A multigroup, multiphase driving system includes a power converter that converts direct current power into alternating current power and vice versa, a direct current power supply connected to a direct current side of the power converter to be charged with and discharge direct current power, and a rotary electric machine connected to an alternating current side of the power converter and including a plurality of groups of multiphase armature windings, and further including a determination unit that determines the number of groups to be used to drive the rotary electric machine on the basis of a rotation speed of the rotary electric machine, a current flowing through the rotary electric machine, a direct current power supply voltage of the direct current power supply, and a carrier frequency of the power converter, the multigroup, multiphase driving system overall loss in the system can be reduced.
    Type: Application
    Filed: May 27, 2015
    Publication date: January 19, 2017
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Yoshihiro MIYAMA, Moriyuki HAZEYAMA, Akihiro DAIKOKU
  • Publication number: 20160285335
    Abstract: In a mechanically and electrically integrated rotary electric machine, a motor portion and an inverter portion are inserted inside a cylindrical frame. The motor portion has a plurality of coils. The inverter portion has a plurality of switching elements. The coils and the switching elements are electrically connected by a connector. The connector has: an end portion connector that distributes sinusoidal electric currents from the switching elements to the respective coils; and a plurality of axial connectors that direct the sinusoidal electric currents from the switching elements to the end portion connector. The end portion connector is disposed on an end portion of the motor portion near an output shaft. The axial connectors are disposed parallel to an axial direction of the frame so as to pass from the switching elements through a mounted region of the motor portion.
    Type: Application
    Filed: June 9, 2014
    Publication date: September 29, 2016
    Applicant: Mitsubishi Electric Corporation
    Inventors: Norihiro WATANABE, Yoshihiro MIYAMA, Hideaki ARITA, Akihiro DAIKOKU
  • Publication number: 20160276895
    Abstract: In a mechanically and electrically integrated driving apparatus, a common coolant flow channel for cooling a motor unit and an inverter unit is disposed inside a wall portion of a frame unit. Power modules are placed in close contact with an inner wall surface of the frame unit. A bracket that is separate from the frame unit is fitted into the frame unit. A space inside the frame unit is divided by the bracket into: a space in which the motor unit is housed; and a space in which the inverter unit is housed.
    Type: Application
    Filed: October 20, 2014
    Publication date: September 22, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Junichi AIZAWA, Yoshihiro MIYAMA, Akihiro DAIKOKU, Norihiro WATANABE, Hideaki ARITA, Shota HANIOKA, Shigetoshi IPPOSHI
  • Publication number: 20160248308
    Abstract: A first stator core and a second stator ore are configured by arranging core block pairs into an annular shape, the core block pairs being configured by stacking together core blocks so as to be spaced apart axially, each of the core blocks including a core back portion and one tooth, and a permanent magnet is configured so as to be divided into a plurality of magnet blocks that each include: a base portion; one shaft portion that protrudes radially inward from an inner circumferential surface of the base portion; and flange portions that protrude on two circumferential sides from a radially inner end portion of the shaft portion, the magnet blocks being held between the core block pairs such that the base portion and the shaft portion are positioned inside the core block pairs and such that the flange portions protrude circumferentially from the core block pairs.
    Type: Application
    Filed: July 16, 2014
    Publication date: August 25, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Toru OGAWA, Hideaki ARITA, Akihiro DAIKOKU, Taiga KOMATSU, Yoshihiro MIYAMA
  • Publication number: 20160226355
    Abstract: A first stator core and a second stator core are configured by arranging pairs of core blocks into an annular shape, the pairs of core blocks being configured by stacking together core blocks so as to be spaced apart axially, the core blocks including circular arc-shaped core back portions and teeth, permanent magnets are each configured so as to be divided into a plurality of magnet blocks that are held between the pairs of core blocks so as to fit inside the pairs of core blocks, and the magnet blocks include a base portion that is held between the core back portions, and that has an external shape in which two circumferential side surfaces are positioned circumferentially inside two circumferential side surfaces of the core back portions.
    Type: Application
    Filed: June 18, 2014
    Publication date: August 4, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Hideaki ARITA, Akihiro DAIKOKU, Hirofumi DOI
  • Publication number: 20160164387
    Abstract: A squirrel-cage rotor manufacturing method capable of suppressing, at the time of performing die-casting, formation of gaps between closing portions and a rotor core at radially outer parts of rotor slots, or generation of a thermal stress in the rotor core as a result of expansion of the closing portions. The squirrel-cage rotor manufacturing method includes: arranging, through die-casting, conductors into rotor slots that are formed along a radially outer part of a rotor core; and performing the die-casting under a state in which radially outer parts of the rotor slots are closed with closing portions made of the same material as a material of the rotor core.
    Type: Application
    Filed: December 15, 2014
    Publication date: June 9, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Taiga KOMATSU, Hideaki ARITA, Akihiro DAIKOKU, Yoshihiro MIYAMA, Moriyuki HAZEYAMA
  • Publication number: 20160126791
    Abstract: A rotating electric machine including a rotator including a small-angle rotator portion and a large-angle rotator portion respectively having different inter-magnet end angles, each being a plane angle formed between a line connecting one outermost peripheral-side end of a permanent magnet and an axial center of the rotator and a line connecting an outermost peripheral-side end of another permanent magnet and the axial center of the rotator. The rotator includes three layers of the small-angle rotator portion, the large-angle rotator portion, and the small-angle rotator portion, which are laminated in the stated order along an axial line of the rotator. Therefore, demagnetization due to a temperature rise of the permanent magnets is suppressed. In addition, a temperature distribution in the permanent magnets in the axial direction of the rotator is reduced.
    Type: Application
    Filed: May 15, 2014
    Publication date: May 5, 2016
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Moriyuki HAZEYAMA, Akihiro DAIKOKU
  • Publication number: 20150357870
    Abstract: Permanent magnets that form individual magnetic poles are configured by arranging three magnet blocks to be spaced apart from each other circumferentially, the three magnet blocks are each formed such that cross-sectional shapes that are perpendicular to a central axis of a rotor core are radially outwardly convex, and circumferential widths are narrower in magnet blocks that are further away from a magnetic pole center, and the three magnet blocks that are arranged circumferentially are formed to have mirror symmetry relative to a plane that passes through the magnetic pole center and the central axis of the rotor core.
    Type: Application
    Filed: January 17, 2014
    Publication date: December 10, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Moriyuki HAZEYAMA, Takuma SASAI, Shinsuke KAYANO, Masaya INOUE, Shinji NISHIMURA, Akihiro DAIKOKU
  • Publication number: 20150130322
    Abstract: A tooth of a stator has a tapered shape in which a tooth width decreases toward a distal end portion thereof. A winding is formed of an edgewise winding wound around the tooth in a row. The winding is supplied with power so that a terminal on a base portion side of the tooth may have a higher voltage than that of a terminal on the distal end portion side thereof. A tooth width Th of the base portion is set within the range of Tmin<Th<1.25Tha defined by a tooth width Tha that maximizes an index using an outer radius and a core back width of a stator core, a clearance of the windings in the slot, a winding width, an air gap between the teeth and the winding, a pitch of the slot, and an inclination angle of the winding, and a permissible lower limit Tmin.
    Type: Application
    Filed: June 4, 2013
    Publication date: May 14, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Moriyuki Hazeyama, Hideaki Arita, Yoshihiro Miyama, Akihiro Daikoku
  • Publication number: 20140354101
    Abstract: A rotor is formed with a partition wall interposed between a first magnetic body and a second magnetic body. Projections of the partition wall block gaps between salient poles of the first magnetic body and salient poles of the second magnetic body which are arranged at shifted positions when seen in an axial direction of a rotating shaft to shield a flow of air flowing in the axial direction. Notches are formed in parts other than the gaps to decrease a volume thereof and to reduce inertia thereof.
    Type: Application
    Filed: April 10, 2012
    Publication date: December 4, 2014
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Takashi Goto, Hideaki Arita, Kanji Shinkawa, Akihiro Daikoku
  • Patent number: 8601671
    Abstract: In a combination of, for example, a rotor having eight magnetic poles and a stator having twelve slots and pulsating components of permeance, which generate a sinusoidal cogging torque having maxima of the same number as the number of poles of the rotor, pressurizing parts arranged in predetermined positions, applying a force at an outer periphery of the stator and directed inwardly cancels the pulsating components of the cogging torque.
    Type: Grant
    Filed: August 15, 2012
    Date of Patent: December 10, 2013
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Yukari Toide, Akihiro Daikoku, Masatsugu Nakano, Hideaki Arita, Shinichi Yamaguchi, Moriyuki Hazeyama, Takashi Yoshioka, Tomohiro Kikuchi, Katsumi Hayami, Takashi Miyazaki
  • Publication number: 20120304453
    Abstract: In a combination of, for example, a rotor having eight magnetic poles and a stator having twelve slots and pulsating components of permeance, which generate a sinusoidal cogging torque having maxima of the same number as the number of poles of the rotor, pressurizing parts arranged in predetermined positions, applying a force at an outer periphery of the stator and directed inwardly cancels the pulsating components of the cogging torque.
    Type: Application
    Filed: August 15, 2012
    Publication date: December 6, 2012
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yukari Toide, Akihiro Daikoku, Masatsugu Nakano, Hideaki Arita, Shinichi Yamaguchi, Moriyuki Hazeyama, Takashi Yoshioka, Tomohiro Kikuchi, Katsumi Hayami, Takashi Miyazaki
  • Patent number: 8143824
    Abstract: A regenerating braking system is provided, which includes: a synchronous motor with field coil excitation including a cylindrical stator coil, an inverter electrically connected to the stator coil, a battery electrically connected to the inverter, a rotor coil provided in an internal space of the stator coil, a two-way switch electrically connected to the rotor coil, and a capacitor electrically connected to the two-way switch; and a controller, wherein when the first differential calculus of acceleration of a load on the synchronous motor becomes negative, the controller stores regenerative power regenerated in the rotor coil from the stator coil, in the capacitor through the two-way switch, and wherein the controller supplies the regenerative power stored in the capacitor to the rotor coil through the two-way switch.
    Type: Grant
    Filed: June 4, 2009
    Date of Patent: March 27, 2012
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kenrou Mitsuda, Masaya Inoue, Ikurou Suga, Akihiro Daikoku
  • Publication number: 20110047782
    Abstract: In a combination of, for example, a rotor having eight magnetic poles and a stator having twelve slots and pulsating components of permeance, which generate a sinusoidal cogging torque having maxima of the same number as the number of poles of the rotor, pressurizing parts arranged in predetermined positions, applying a force at an outer periphery of the stator and directed inwardly cancels the pulsating components of the cogging torque.
    Type: Application
    Filed: November 10, 2010
    Publication date: March 3, 2011
    Applicant: MITSUBISHI DENKI KABUSHIKI KAISHA
    Inventors: Yukari Toide, Akihiro Daikoku, Masatsugu Nakano, Hideaki Arita, Shinichi Yamaguchi, Moriyuki Hazeyama, Takashi Yoshioka, Tomohiro Kikuchi, Katsumi Hayami, Takashi Miyazaki
  • Patent number: 7856702
    Abstract: A method for manufacturing an armature including securing a core to the shaft having a plurality of slots extending in the axial direction formed on the outer circumferential surface thereof, forming a coil composed of a plurality of coil portions by simultaneously winding wires a plurality of turns around a pair of slots separated by a predetermined number of slots and offsetting each of the coil portions one slot at a time in the circumferential direction of the core, securing a commutator to the shaft having a plurality of segments, adjacent coil portions having a slot along one side thereof, wherein a number of vacant slots between adjacent ones of the coil portions within each of simultaneously-wound coil portion groups is nonuniform, and electronically connecting segments which should have the same electric potential by means of equalizing connectors so that each of pairs of the coil portions that should have the same electric potential has a substantially equal electric potential.
    Type: Grant
    Filed: July 10, 2006
    Date of Patent: December 28, 2010
    Assignee: Mitsubishi Denki Kabushiki Kaisha
    Inventors: Toshinori Tanaka, Kyouhei Yamamoto, Akihiro Daikoku, Akihiko Imagi, Yoshio Yoshikuwa, Mitsuyuki Tsumura