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: 20160241092
    Abstract: A permanent magnet embedded electric motor includes a stator core disposed inside the frame and having a back yoke and a plurality of magnetic pole teeth; a rotor disposed on an inner diameter side of the plurality of magnetic pole teeth; and compression sections in which compression stress higher than compression stress occurring in the back yoke due to pressing force generated between the frame and the back yoke occurs. A compression section group having a set of two or more compression sections and of the plurality of compression sections is disposed on an outer circumferential section of the stator core. A sum of the rotating direction widths of the plurality of compression sections constituting the compression section group is smaller than a radial direction thickness of the frame.
    Type: Application
    Filed: September 1, 2014
    Publication date: August 18, 2016
    Inventors: Masahiro NIGO, Kazuchika TSUCHIDA, Kazuhiko BABA
  • Publication number: 20160211709
    Abstract: An interior permanent magnet motor includes a stator and a rotor. The rotor includes a rotor core formed by laminating a plurality of plate members. The rotor core has a plurality of magnet insertion holes formed therein, into which corresponding permanent magnets are respectively inserted. At least one slit and at least one caulked portion are formed between a rotor outer peripheral surface of the rotor and a radially-outer insertion hole contour surface of the magnet insertion hole. At least a part of the caulked portion is positioned between a pair of width extended lines of the slit.
    Type: Application
    Filed: September 18, 2014
    Publication date: July 21, 2016
    Inventors: Kazuchika TSUCHIDA, Masahiro NIGO, Kazuhiko BABA, Atsushi ISHIKAWA, Tomoaki OIKAWA
  • Publication number: 20160190880
    Abstract: An interior permanent magnet motor includes: a rotator; a stator; a permanent magnet inserted into a magnet accommodating hole; and a slit formed on a radially outer side of the magnet accommodating hole. A space portion is ensured between a radially outer surface of the permanent magnet and a rotator core in each region opposed to the slit. The permanent magnet is apart from the rotator core via the space portion in the each region opposed to the slit.
    Type: Application
    Filed: June 12, 2013
    Publication date: June 30, 2016
    Inventors: Kazuhiko BABA, Koji YABE, Masahiro NIGO, Tomoaki OIKAWA
  • Publication number: 20160181877
    Abstract: In an interior permanent magnet motor, a plurality of slits are formed between a rotor outer peripheral surface of a rotor and a radially-outer insertion hole contour surface of a magnet insertion hole. Assuming that a total area of the plurality of slits per magnetic pole is represented by Ss, and an area of a region in a rotor core on a radially outer side with respect to the corresponding one magnet insertion hole is represented by Si, the plurality of slits are formed so as to satisfy a relationship of 0.35?Ss/Si?0.5.
    Type: Application
    Filed: September 25, 2013
    Publication date: June 23, 2016
    Inventors: Atsushi ISHIKAWA, Masahiro NIGO, Kazuchika TSUCHIDA, Kazuhiko BABA
  • Publication number: 20160172912
    Abstract: In an interior permanent magnet motor, each of permanent magnets has a radially-inner magnet contour surface, a radially-outer magnet contour surface, and a pair of side-end magnet contour surfaces. Each of magnet insertion holes has a radially-inner insertion hole contour surface, a radially-outer insertion hole contour surface, and a pair of side-end insertion hole contour surfaces. The radially-outer magnet contour surface and the radially-outer insertion hole contour surface are each formed by a first arc surface. The radially-inner magnet contour surface and the radially-inner insertion hole contour surface are each formed by a second arc surface and at least one straight surface configured to suppress movement of the permanent magnet along the magnet insertion hole having an arc shape.
    Type: Application
    Filed: August 26, 2014
    Publication date: June 16, 2016
    Inventors: Masahiro NIGO, Kazuchika TSUCHIDA, Kazuhiko BABA
  • Publication number: 20160172913
    Abstract: In an interior permanent magnet motor, at least one magnetic pole center slit and a plurality of side slits are formed between a rotor outer peripheral surface of a rotor and a radially-outer insertion hole contour surface of a magnet insertion hole. The plurality of side slits are formed so that at least one side slit is formed on each of both sides of the magnetic pole center slit in a width direction. The area of the magnetic pole center slit is smaller than the area of each of the plurality of side slits. A width of each of the plurality of side slits is larger than an interval between the adjacent slits.
    Type: Application
    Filed: September 25, 2013
    Publication date: June 16, 2016
    Inventors: Kazuhiko BABA, Masahiro NIGO, Kazuchika TSUCHIDA, Atsushi ISHIKAWA
  • Patent number: 9276445
    Abstract: A rotor, constituting an interior permanent magnet motor, includes magnets that are inserted into the rotor, and a rotor core containing magnet insertion pockets to which the magnets are inserted, and, when the magnets are inserted, the magnet insertion pockets are formed to provide openings in areas except both ends of an inner circumferential face, at both ends in a circumferential direction of the magnets.
    Type: Grant
    Filed: October 26, 2011
    Date of Patent: March 1, 2016
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazuchika Tsuchida, Masahiro Nigo, Koji Yabe, Tomoaki Oikawa
  • Patent number: 9236776
    Abstract: A rotor, constituting an interior permanent magnet motor, includes magnets that are inserted into the rotor, and a rotor core containing magnet insertion pockets to which the magnets are inserted, and, when the magnets are inserted, the magnet insertion pockets are formed to provide openings in areas except both ends of an inner circumferential face, at both ends in a circumferential direction of the magnets.
    Type: Grant
    Filed: October 26, 2011
    Date of Patent: January 12, 2016
    Assignee: Mitsubishi Electric Corporation
    Inventors: Kazuchika Tsuchida, Masahiro Nigo, Koji Yabe, Tomoaki Oikawa
  • Publication number: 20150372548
    Abstract: A rotor outer peripheral surface includes first arcs and second arcs. The first arc is positioned in a magnetic pole center portion. The second arc is positioned in an inter-pole portion. The first arc bulges toward a radially outer side to a higher degree than the second arc. An air gap is varied in a manner of being increased as approaching from each of the magnetic pole center portions to the adjacent inter-pole portions. A hole defining portion of a magnet insertion hole on the radially outer side has a curvature of a third arc, and a hole defining portion of the magnet insertion hole on a radially inner side has a curvature of a fourth arc. An opening angle of a tooth tip portion, an opening angle of the first arc, and an opening angle of the third arc coincide with each other.
    Type: Application
    Filed: February 14, 2013
    Publication date: December 24, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Masahiro NIGO, Kazuhiko BABA, Kazuchika TSUCHIDA
  • Publication number: 20150364959
    Abstract: An interior permanent magnet motor includes: a rotor; a stator; and a plurality of permanent magnets respectively inserted into a plurality of magnet insertion holes formed in a rotor core, the rotor core being formed by laminating a plurality of magnetic steel sheets, the magnetic steel sheets including first magnetic steel sheets each not having a magnet stopper in the magnet insertion hole, and second magnetic steel sheets each having magnet stoppers at both end portions of the magnet insertion hole, the rotor core including a laminate of the magnetic steel sheets in a lamination mode in which, when Hn represents a distance between an upper end surface of the second magnetic steel sheet and an upper end surface of the n-th second magnetic steel sheet, a progression of differences of Hn is a geometric progression.
    Type: Application
    Filed: February 20, 2013
    Publication date: December 17, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Naohiro OKETANI, Masahiro NIGO, Kazuhiko BABA, Koji YABE
  • Publication number: 20150318764
    Abstract: A permanent magnet buried type electric motor includes a rotator having a rotator core and a stator. The rotator core includes: a plurality of magnet accommodating holes formed as many as the number of poles; a plurality of permanent magnets; air holes through which a coolant and a refrigerant oil pass; and a fastening hole. The magnet accommodating hole is formed into a shape that projects toward a radially inner side and is recessed toward a radially outer side. The air hole portions and the fastening holes are arranged so as to be alternately positioned. The air hole portion is formed into such a shape that includes a portion extending in an arc shape along an outer peripheral surface of a rotary shaft in a circumferential direction of the rotator core so that an area of the air hole portion is larger than an area of the fastening hole.
    Type: Application
    Filed: December 21, 2012
    Publication date: November 5, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kazuhiko BABA, Masahiro NIGO, Kazuchika TSUCHIDA
  • Publication number: 20150318743
    Abstract: An interior permanent magnet motor capable of increasing an output of a motor without reducing torque by increasing demagnetization resistance. The interior permanent magnet motor includes a rotator including a rotator core, and a stator. The rotator core includes a plurality of magnet accommodating holes and a plurality of permanent magnets. The thickness in the short-side direction of each of the magnet accommodating holes is minimum at the center portion of the magnetic pole, and is gradually increased toward the radially outer side of the rotator core. At least the thickness in the short-side direction of the permanent magnet at the center portion of the magnetic pole is equal to the thickness in the short-side direction of the magnet accommodating hole at the center portion of the magnetic pole.
    Type: Application
    Filed: September 20, 2013
    Publication date: November 5, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kazuhiko BABA, Masahiro NIGO, Kazuchika TSUCHIDA
  • Publication number: 20150280500
    Abstract: A rotor core includes a plurality of first electromagnetic steel plates that are stacked in an axial direction and a plurality of second electromagnetic steel plates that are stacked in an axial direction at both ends of the electromagnetic steel plate group thereof. The first electromagnetic steel plates are provided therein with magnet insertion holes and first flux barriers. The second electromagnetic steel plates are provided therein with the magnet insertion holes, second flux barriers, and projections that regulate the positions of the magnets. The second electromagnetic steel plates are stacked at at least one of the axial direction ends of the electromagnetic steel plate group including the plurality of first electromagnetic steel plates and are provided at a position overhanging the axial direction end of a stator core.
    Type: Application
    Filed: November 1, 2012
    Publication date: October 1, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Masahiro NIGO, Naohiro OKETANI, Koji YABE, Kazuhiko BABA
  • Publication number: 20150256038
    Abstract: A permanent magnet embedded electric motor includes a slit and a flux barrier. A hole defining portion of a magnet insertion hole includes an extended portion. The extended portion projects toward an interpolar core portion in a rotor core in an area positioned further on an outer side of a circumferential direction with respect to a width-direction end surface of a permanent magnet. (Lb) is larger than (La), and (Lc) is smaller than (Ld), where the (La) represents a distance between the slit and the core outer peripheral surface; the (Lb) represents a distance between the slit and an outer peripheral-side surface of the permanent magnet; the (Lc) represents a shortest distance between the extended portion and the interpolar core portion; and the (Ld) represents a thickness of the permanent magnet.
    Type: Application
    Filed: October 29, 2013
    Publication date: September 10, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Masahiro Nigo, Naohiro Oketani, Koji Yabe, Kazuhiko Baba
  • Publication number: 20150236558
    Abstract: A rotor of an interior permanent magnet motor includes a rotor core having a plurality of magnet insertion holes, a shaft, a plurality of rare-earth magnets, and a pair of magnet fixing members. One surface of the magnet fixing member is provided with a plurality of pairs of tongue-like portions, and the tongue-like portions are inserted into the magnet insertion holes. On each of both sides in a rotary shaft direction, the rare-earth magnets have both end surfaces in a rotor circumferential direction sandwiched by a corresponding pair of tongue-like portions. An interval between the tongue-like portions includes, at a position separated from a base position, an interval that is smaller than the width of the rare-earth magnet in the rotor circumferential direction.
    Type: Application
    Filed: October 2, 2013
    Publication date: August 20, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Naohiro Oketani, Masahiro Nigo, Kazuhiko Baba, Koji Yabe
  • Publication number: 20150139830
    Abstract: In a permanent-magnet-embedded electric motor, at the distal ends of base sections of teeth sections of a stator core, increased magnetic-resistance sections, which have magnetic resistance larger than magnetic resistance of the base sections, are provided. Given that a minimum interval in the circumferential direction between the base sections adjacent to each other is represented as La, an interval of a minimum gap between the teeth sections adjacent to each other is represented as Lb, and an interval of a gap between a rotor and a stator is represented as Lg, a relation of La>2Lg>Lb holds. Due to such a configuration, it is possible to provide the electric motor that does not spoil a magnetic characteristic of the rotor and that is excellent in a demagnetization characteristic.
    Type: Application
    Filed: June 26, 2012
    Publication date: May 21, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Masahiro Nigo, Kazuhiko Baba, Kazuchika Tsuchida
  • Publication number: 20150137646
    Abstract: A rotor includes a plurality of magnets, and an annular rotor core having a plurality of magnet insertion holes formed in a circumferential direction, into which the magnets are respectively inserted, in which each of the magnet insertion holes is formed with a protruding portion A on an inner wall surface on an inner diameter side in a radial direction of the rotor, and each of the magnets is formed with a recessed portion that is fitted to the protruding portion A when the magnet is inserted into the magnet insertion holes. With this configuration, fixation of the magnets is facilitated, and generation of chipping and vibration noise due to a movement of the magnets at the time of activation or rotation can be suppressed, thereby enabling to provide the rotor having high quality and high reliability.
    Type: Application
    Filed: April 6, 2012
    Publication date: May 21, 2015
    Applicant: Mitsubishi Electric Corporation
    Inventors: Kazuchika Tsuchida, Masahiro Nigo
  • Publication number: 20150084468
    Abstract: A rotor for a permanent-magnet-embedded electric motor includes slit holes each axially formed near opposite ends of a magnetic pole between an outer peripheral face of a rotor core and a magnet insertion hole, and forming a symmetrical shape in an approximately truncated chevron shape along the outer peripheral face of the rotor core, based on a centerline of each of the magnetic poles, wherein a thickness of each of permanent magnets is set to be twice or more of an air gap, a width of a shortest magnetic path in which a distance between the slit hole and the permanent magnet becomes shortest is set to be twice or more of the air gap, and an inclination of the slit hole with respect to a width direction of the permanent magnet orthogonal to a radial direction is set to be in a range from 0 to 30 degrees.
    Type: Application
    Filed: January 30, 2012
    Publication date: March 26, 2015
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Masahiro Nigo, Kazuhiko Baba, Kazuchika Tsuchida
  • Publication number: 20140346911
    Abstract: A rotor includes a rotor iron core in which magnet insertion holes that are arrayed in a radial direction so as to be convex toward an inner peripheral side are provided for each magnetic pole, and in which the magnet insertion holes are arranged in a circumferential direction according to the number of magnetic poles, and flat-shaped permanent magnets that are inserted respectively in the magnet insertion holes, wherein the magnet insertion holes, which are arranged on an innermost peripheral side and adjacent to each other in a circumferential direction are provided in such a manner that the width of the magnet insertion hole gradually becomes larger toward the inner peripheral side such that the width of the iron core between the adjacent magnet insertion holes in a circumferential direction is constant in a radial direction.
    Type: Application
    Filed: December 26, 2011
    Publication date: November 27, 2014
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kazuchika Tsuchida, Masahiro Nigo
  • Publication number: 20140265705
    Abstract: A rotor, constituting an interior permanent magnet motor, includes magnets that are inserted into the rotor, and a rotor core containing magnet insertion pockets to which the magnets are inserted, and, when the magnets are inserted, the magnet insertion pockets are formed to provide openings in areas except both ends of an inner circumferential face, at both ends in a circumferential direction of the magnets.
    Type: Application
    Filed: October 26, 2011
    Publication date: September 18, 2014
    Applicant: MITSUBISHI ELECTRIC CORPORATION
    Inventors: Kazuchika Tsuchida, Masahiro Nigo, Koji Yabe, Tomoaki Oikawa