Patents by Inventor Masahiro Nigo

Masahiro Nigo 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).

  • Publication number: 20220166270
    Abstract: A rotor core has a magnet insertion hole, an opening formed adjacent to the magnet insertion hole in the circumferential direction, and a thin wall portion formed between the opening and an outer circumference of the rotor core. A stator core has a length in the axial direction shorter than that of the rotor core. The rotor core has a facing region where the rotor core faces the stator core in the radial direction and an overhang region where the rotor core protrudes from the stator core in the axial direction. A distance from the center axis to a portion of the outer circumference located on a radially outer side of the magnet insertion hole is longer in at least part of the overhang region than in the facing region. The minimum width of the thin wall portion in the radial direction is the same in both regions.
    Type: Application
    Filed: February 21, 2019
    Publication date: May 26, 2022
    Inventors: Masahiro NIGO, Yuji HIROSAWA, Emi TSUKAMOTO
  • Publication number: 20220103030
    Abstract: A motor includes a stator core having an annular shape about an axis, a coil wound on the stator core, and a rotor core disposed on an inner side of the stator core in a radial direction about the axis. The rotor core has a stacked body in which a plurality of steel laminations are stacked in a direction of the axis, and a magnet insertion hole famed in the stacked body. The rotor core has a length in the direction of the axis longer than that of the stator core. A magnet is inserted in the magnet insertion hole. The rotor core has a first region where the magnet is inserted in the magnet insertion hole and a second region where the magnet is not inserted in the magnet insertion hole, in the direction of the axis. At least one steel lamination in the second region of the rotor core has an opening area smaller than an opening area of each steel lamination in the first region of the rotor core.
    Type: Application
    Filed: February 22, 2019
    Publication date: March 31, 2022
    Inventors: Emi TSUKAMOTO, Masahiro NIGO
  • Patent number: 11199351
    Abstract: An air conditioner includes a compressor having a compressor motor including coils, an indoor fan having a fan motor, a connection switching unit that switches a connection state of the coils between a first connection state and a second connection state in which a line voltage is lower than a line voltage in the first connection state, and a controller that controls the compressor motor, the fan motor, and the connection switching unit. The controller provides a stop period during which rotation of the compressor motor stops before the connection switching unit switches the connection state of the coils, and rotates the fan motor for at least a time period within the stop period.
    Type: Grant
    Filed: May 10, 2017
    Date of Patent: December 14, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yuji Hirosawa, Masahiro Nigo
  • Patent number: 11139769
    Abstract: A driving device drives a motor having coils. The driving device includes a connection switching unit to switch a connection state of the coils, a temperature sensor to detect a room temperature, and a controller to switch the connection state of the coils based on a detected temperature by the temperature sensor.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: October 5, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventor: Masahiro Nigo
  • Publication number: 20210273506
    Abstract: An electric motor includes: a stator including a first stator core, a second stator core, and a slot in which a stator winding is disposed, and a rotor including a first rotor core facing a first stator core in a radial direction and a second stator core facing the second stator core in the radial direction. The first stator core and the second stator core are laminated in an axial direction. The stator includes a depression formed in a position facing the slot and not touching the stator winding. A volume of the first rotor core is smaller than a volume of the second rotor core.
    Type: Application
    Filed: July 27, 2018
    Publication date: September 2, 2021
    Inventors: Tomoki MASUKO, Masahiro NIGO
  • Patent number: 11101763
    Abstract: An air conditioner includes a signal receiving unit to receive an operation instruction signal, a compressor including a motor including coils, an inverter connected to the coils, a connection switching unit to switch a connection state of the coils between a first connection state and a second connection state, and a controller to control the inverter and the connection switching unit. When the signal receiving unit receives an operation stop signal, the connection switching unit switches the connection state of the coils from the first connection state to the second connection state.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: August 24, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventor: Masahiro Nigo
  • Publication number: 20210211085
    Abstract: A driving device drives a motor including a rotor having a neodymium rare earth magnet. The driving device includes an inverter, a first detector that outputs a first detection signal corresponding to a motor driving current supplied to the motor, a protection level setting unit that sets an overcurrent protection level, a second detector that outputs a second detection signal corresponding to a driving state of the motor, and a control device. The control device executes first control of lowering the motor driving current immediately after the motor driving current corresponding to the first detection signal exceeds the overcurrent protection level. When the protection level setting unit lowers the overcurrent protection level to a new current level based on the second detection signal, the control device executes second control of lowering the motor driving current to a level lower than the new current level.
    Type: Application
    Filed: November 21, 2018
    Publication date: July 8, 2021
    Inventor: Masahiro NIGO
  • Publication number: 20210203196
    Abstract: A rotor core has steel laminations stacked in the axial direction, and a permanent magnet is embedded in the rotor core. A stator core has steel laminations stacked in the axial direction, and a coil is wound on the stator core. The stator core has a slot for housing the coil. The stator core has a first core portion at an end portion in the axial direction and a second core portion at a center portion in the axial direction. An area of the slot is larger in the first core portion than in the second core portion. A sheet thickness T0 and a lamination gap L0 of the steel laminations of the rotor core and a sheet thickness T1 and a lamination gap L1 of the steel laminations of the first core portion of the stator core satisfy at least one of 0.05 mm?T0?T1?0.15 mm and L0<L1.
    Type: Application
    Filed: July 27, 2018
    Publication date: July 1, 2021
    Inventor: Masahiro NIGO
  • Publication number: 20210164715
    Abstract: A refrigerating cycle device includes a compressor, a motor, and a wiring switch part. The compressor compresses a refrigerant. The motor generates power for compressing the refrigerant by rotating a rotor with voltage applied to a plurality of wirings. The motor is disposed in the compressor. The wiring switch part switches between a plurality of wiring states by changing connection between the plurality of wirings. When a rotational speed of the rotor exceeds a predetermined value, the wiring switch part switches to a first wiring state of the plurality of wiring states. The first wiring state differs from a second wiring state of the plurality of wiring state. Efficiency of the second wiring state is highest at the rotational speed.
    Type: Application
    Filed: April 25, 2018
    Publication date: June 3, 2021
    Inventors: Takumi NISHIYAMA, Koichi ARISAWA, Masahiro NIGO, Kazunori HATAKEYAMA
  • Patent number: 11018535
    Abstract: A motor includes a stator and a rotor provided inside the stator. The rotor includes a rotor core having a magnet insertion hole and two permanent magnets disposed in the magnet insertion hole. The rotor core has a first magnet holding portion disposed between the two permanent magnets and holding the two permanent magnets, an opening disposed on an inner side of the first magnet holding portion in a radial direction of the rotor core, and a center hole disposed at a center of the rotor core in the radial direction. A distance from the opening to the magnet insertion hole is shorter than a distance from the opening to the center hole.
    Type: Grant
    Filed: November 2, 2015
    Date of Patent: May 25, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masahiro Nigo, Yuji Hirosawa, Ryukichi Kijima
  • Patent number: 10965237
    Abstract: A driving device includes a connection switching unit to switch a connection state of coils between a first connection state and a second connection state in which a line voltage is lower than in the first connection state, a controller to control a motor and the connection switching unit, and a rotation speed detector to detect a rotation speed of the motor. When the connection state of the coils is the first connection state and the rotation speed detected by the rotation speed detector becomes higher than or equal to a first rotation speed, the controller causes the motor to rotate at a second rotation speed higher than the first rotation speed, and then causes the connection switching unit to switch the connection state of the coils from the first connection state to the second connection state.
    Type: Grant
    Filed: July 25, 2017
    Date of Patent: March 30, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masahiro Nigo, Yuji Hirosawa
  • Patent number: 10951139
    Abstract: A driving device includes a connection switching unit that switches connection condition of a coil between Y connection and delta connection, an inverter, and a control device that controls a carrier frequency of the inverter. The carrier frequency is set at a first carrier frequency when the connection condition of the coil is the Y connection. The carrier frequency is set at a second carrier frequency when the connection condition of the coil is the delta connection.
    Type: Grant
    Filed: July 28, 2017
    Date of Patent: March 16, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yuji Hirosawa, Masahiro Nigo
  • Publication number: 20210050757
    Abstract: Two types of insulating members, i.e., end surface insulators and slot insulators are provided. On tooth portion sides of both side surfaces in the circumferential direction of tooth end surface covering portions of the end surface insulator, first cutouts recessed in the circumferential direction are provided so as to extend in the radial direction. A part axially upward of the first cutouts protrudes in the circumferential direction to form a first overhang portion, and the slot insulator is accommodated between the first overhang portions of two end surface insulators.
    Type: Application
    Filed: March 15, 2019
    Publication date: February 18, 2021
    Applicant: Mitsubishi Electric Corporation
    Inventors: Shuichi KITANO, Masahiro NIGO, Kazuya KUMAGAI, Ryo ISHIDA, Hironori TSUIKI, Moriyuki HAZEYAMA
  • Patent number: 10916977
    Abstract: A stator includes: a stator core including a first core part formed by at least one first sheet and a second core part provided on a side face of the first core part and formed by at least one second sheet; and a winding wound around an outer periphery of the first core part and the second core part.
    Type: Grant
    Filed: October 11, 2016
    Date of Patent: February 9, 2021
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masahiro Nigo, Yuji Hirosawa
  • Patent number: 10833544
    Abstract: A stator includes a first core including a plurality of non-oriented electromagnetic steel sheets stacked in layers and having an insertion hole penetrating the plurality of non-oriented electromagnetic steel sheets in an axial direction of the stator and a second core arranged in the insertion hole and including a plurality of oriented electromagnetic steel sheets stacked in layers. The first core has a side wall part adjoining a side surface of the second core extending in the axial direction of the stator, and the side wall part has an opening part that exposes the side surface of the second core.
    Type: Grant
    Filed: May 30, 2016
    Date of Patent: November 10, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazuhiko Baba, Masahiro Nigo
  • Patent number: 10804754
    Abstract: A permanent magnet embedded motor includes a cylindrical stator core disposed on an inner side of a cylindrical frame and configured by stacking a first annular core and a second annular core disposed to be adjacent to the first annular core in an axial direction of the frame, and a rotor disposed on an inner side of the stator core. The second annular core is fixed to the first annular core by using swaging portions formed in the second annular core, and adjacent first yokes are in contact with each other, while adjacent second yokes are separated from each other.
    Type: Grant
    Filed: August 21, 2015
    Date of Patent: October 13, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Masahiro Nigo, Kazuchika Tsuchida, Sadami Okugawa, Yoshinori Iwanabe
  • Patent number: 10797540
    Abstract: A stator includes a first core and a second core. The first core has a yoke extending in a circumferential direction about an axis line and having a second insertion hole, and a tooth extending from the yoke in a direction toward the axis line and having a first insertion hole. The second core has a first part disposed in the first insertion hole and a second part disposed in the second insertion hole and formed of amorphous metal or nanocrystal metal.
    Type: Grant
    Filed: May 30, 2016
    Date of Patent: October 6, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazuhiko Baba, Masahiro Nigo
  • Patent number: 10778055
    Abstract: In an electric motor, a first magnet and a second magnet are accommodated in magnet accommodating apertures of a rotor core. On outer circumferential core portions that exist on a radially outer side of the magnet accommodating apertures, two slits as a pair of first slits, and two slits that are respectively adjacent to each of the first slits are disposed circumferentially outside the pair of first slits as a pair of second slits. The outer circumferential core portions include: a first magnetic portion that exists between the pair of first slits; and a pair of second magnetic portions that respectively exist between the first slits and the second slits. An inter-magnet space portion that exists between the first magnet and the second magnet is positioned within a range of the first magnetic portion in the circumferential direction of the rotor.
    Type: Grant
    Filed: February 12, 2016
    Date of Patent: September 15, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazuhiko Baba, Masahiro Nigo, Kazuchika Tsuchida, Atsushi Ishikawa
  • Patent number: 10763773
    Abstract: A driving device drives a motor having coils. The driving device includes a converter to generate a bus voltage, an inverter to convert the bus voltage to an AC voltage and supply the AC voltage to the coils, and a connection switching unit to switch a connection state of the coils. The bus voltage generated by the converter is switched in accordance with the connection state of the coils.
    Type: Grant
    Filed: October 31, 2016
    Date of Patent: September 1, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventor: Masahiro Nigo
  • Patent number: 10763717
    Abstract: A stator core includes a first core portion including a plurality of first plates stacked in a first direction; a second core portion including a plurality of second plates stacked in the first direction; and a third core portion including a plurality of third plates stacked in at least one direction orthogonal to the first direction, the third core portion being sandwiched between the first core portion and the second core portion. The third core portion has a yoke portion formed of a subset of the plurality of third plates stacked in a second direction orthogonal to the first direction.
    Type: Grant
    Filed: September 13, 2016
    Date of Patent: September 1, 2020
    Assignee: Mitsubishi Electric Corporation
    Inventors: Yuji Hirosawa, Masahiro Nigo