Patents by Inventor Keiji Oda

Keiji Oda 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: 6822360
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.
    Type: Grant
    Filed: January 9, 2003
    Date of Patent: November 23, 2004
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6798103
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.
    Type: Grant
    Filed: January 5, 2001
    Date of Patent: September 28, 2004
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20040174084
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient p9ole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Application
    Filed: March 16, 2004
    Publication date: September 9, 2004
    Applicants: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6734592
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient pole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Grant
    Filed: May 10, 2002
    Date of Patent: May 11, 2004
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20030102757
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.
    Type: Application
    Filed: January 9, 2003
    Publication date: June 5, 2003
    Applicant: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20020149289
    Abstract: A plurality of permanent magnets 6 are embedded in a cylindrical rotor core 8 and arranged in a circumferential direction of the rotor core 8. A pair of side rings 81 are mounted on the axial ends of the rotor core 8. The outer diameter of each side ring 81 is set smaller than the outer diameter of the rotor core 8. With this structure, an eddy current generated in each side ring 81 can be suppressed to thereby prevent abnormal heating and accordingly prevent thermal demagnetization of the permanent magnets 6.
    Type: Application
    Filed: March 28, 2002
    Publication date: October 17, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Keiji Oda, Suetaro Shibukawa
  • Publication number: 20020130575
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient pole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Application
    Filed: May 10, 2002
    Publication date: September 19, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20020130576
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient pole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Application
    Filed: May 10, 2002
    Publication date: September 19, 2002
    Applicant: Hitachi, Ltd. and Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6445100
    Abstract: In order to realize a permanent magnet dynamo electric machine which permits a high speed rotation, the permanent magnet dynamo electrIc machine including a stator 20 having a stator iron core 22 in which a stator winding 24 is wound, and a rotor 30 facing the inner circumference of the stator 20 and rotatably supported thereby, the rotor 30 having a rotor iron core 32 and a plurality of permanent magnets 36 arranged inside the rotor iron core 32 so as to face the stator iron core 22, wherein the rotor iron core 32 is provided with the same number of permanent magnet insertion holes 34 as the plurality of permanent magnets 36 for receiving the same at positions where ratio R1/R0 is equal to or more than 0.85, wherein R0 is the radius of the rotor 30 and R1 is the radius of an imaginary circle drawn by inscribing the faces of the plurality of permanent magnets 36 at the side remote from the stator 20.
    Type: Grant
    Filed: December 5, 2000
    Date of Patent: September 3, 2002
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6426579
    Abstract: A plurality of permanent magnets 6 are embedded in a cylindrical rotor core 8 and arranged in a circumferential direction of the rotor core 8. A pair of side rings 81 are mounted on the axial ends of the rotor core 8. The outer diameter of each side ring 81 is set smaller than the outer diameter of the rotor core 8. With this structure, an eddy current generated in each side ring 81 can be suppressed to thereby prevent abnormal heating and accordingly prevent thermal demagnetization of the permanent magnets 6.
    Type: Grant
    Filed: December 27, 1999
    Date of Patent: July 30, 2002
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Keiji Oda, Suetaro Shibukawa
  • Patent number: 6396183
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient pole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Grant
    Filed: January 21, 2000
    Date of Patent: May 28, 2002
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20010017492
    Abstract: In order to realize a permanent magnet dynamo electric machine which permits a high speed rotation, the permanent magnet dynamo electric machine including a stator 20 having a stator iron core 22 in which a stator winding 24 is wound, and a rotor 30 facing the inner circumference of the stator 20 and rotatably supported thereby, the rotor 30 having a rotor iron core 32 and a plurality of permanent magnets 36 arranged inside the rotor iron core 32 so as to face the stator iron core 22, wherein the rotor iron core 32 is provided with the same number of permanent magnet insertion holes 34 as the plurality of permanent magnets 36 for receiving the same at positions where ratio R1/R0 is equal to or more than 0.85, wherein R0 is the radius of the rotor 30 and R1 is the radius of an imaginary circle drawn by inscribing the faces of the plurality of permanent magnets 36 at the side remote from the stator 20.
    Type: Application
    Filed: December 5, 2000
    Publication date: August 30, 2001
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Publication number: 20010002094
    Abstract: A magnetic gap is provided between permanent magnet of a rotor and an auxiliary magnetic pole portion which is adjacently arranged to the permanent magnet to a peripheral direction. A change in a magnetic flux density distribution of a surface of the rotor is performed moderately and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.
    Type: Application
    Filed: January 5, 2001
    Publication date: May 31, 2001
    Applicant: Hitachi, Ltd. and Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6239525
    Abstract: A permanent magnet dynamoelectric rotating machine comprises a stator provided with windings; and a rotor disposed with an air gap between the stator and the rotor, and provided with a plurality of permanent magnets arranged along the circumference of the rotor and fixed to the rotor. The circumferential length of a surface of each permanent magnet facing the stator is determined so that an induced voltage has a waveform approximate to a sinusoidal waveform to suppress the peak of the induced voltage.
    Type: Grant
    Filed: February 4, 2000
    Date of Patent: May 29, 2001
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Takashi Kobayashi, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6208054
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnetic pole portion which is arranged adjacent to the permanent magnet in a peripheral direction. A gradual change in a magnetic flux density distribution of a surface of the rotor is obtained and a cogging torque and a torque pulsation are restrained. By obtaining a reluctance torque according to the auxiliary magnetic pole, a permanent magnet electric rotating machine in which the cogging torque and the torque pulsation are restrained can be obtained and further an electromotive vehicle having the permanent magnet electric rotating machine can be provided.
    Type: Grant
    Filed: October 7, 1997
    Date of Patent: March 27, 2001
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6188157
    Abstract: An electrically driven motor vehicle having mechanism including a permanent magnet dynamo electric machine which permits high speed of rotation. The permanent magnet dynamo electric machine includes a stator having a stator iron core in which a stator winding is wound, and a rotor facing the inner circumference of the stator and rotatably supported thereby. The rotor has a rotor iron core and a number of permanent magnets arranged in a ring inside the rotor iron core. The rotor iron core is provided with a number of permanent magnet insertion holes equal to the number of permanent magnets so as to position the permanent magnets at positions at which the ratio R1/R0 is equal to or more than 0.85, where R0 is the radius of the rotor and R1 is the radius of an imaginary circle drawn by inscribing the faces of the permanent magnets at the side thereof remote from the stator.
    Type: Grant
    Filed: July 16, 1998
    Date of Patent: February 13, 2001
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6133662
    Abstract: A permanent magnet electric machine comprises a stator provided with windings and a rotor disposed with an air gap between the stator and the rotor. A plurality of permanent magnets are arranged along and fixed to the circumference of the rotor. The angular circumferential extent of a surface of each permanent magnet facing the stator is determined so that an induced voltage in the machine has a waveform that approximates a sinusoidal waveform, to suppress the peak of the induced voltage.
    Type: Grant
    Filed: September 15, 1997
    Date of Patent: October 17, 2000
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Takashi Kobayashi, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 6034460
    Abstract: A rotating electric machine comprises a stator having stator salient poles, three-phases windings wound around said stator salient poles, a rotor rotatable held inside the said stator, and permanent magnets inserted into said rotor and positioned opposite to said stator salient poles, wherein said three-phase windings are concentratively wound around each of said stator salient poles, said windings of each phase are wound around at more than one stator salient pole, and said windings of each phase have a phase difference of voltage between at least one of the windings and the other.
    Type: Grant
    Filed: April 11, 1997
    Date of Patent: March 7, 2000
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd
    Inventors: Fumio Tajima, Yutaka Matsunobe, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • Patent number: 5936323
    Abstract: Plural magnet insertion holes are provided at a vicinity of an outer peripheral of a laminated rotor core toward a circumferential direction and extend toward an axial direction. The magnet insertion holes are divided into plural toward the axial direction and each of the plural magnet insertion holes is shifted at a predetermined angle toward a circumferential direction. The permanent magnet is arranged in the magnet insertion hole and the permanent magnet is fixed to the laminated rotor core through a clearance fill-up agent. The cogging torque is reduced and the reduction in noises is improved and a permanent magnet rotation type rotor constituted by low cost materials is prevented from damaging or destroying by the centrifugal force.
    Type: Grant
    Filed: June 9, 1997
    Date of Patent: August 10, 1999
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Suetaro Shibukawa, Keiji Oda, Kiyoshi Hirano, Yoshikazu Kadowaki, Fumio Tajima
  • Patent number: 5886433
    Abstract: A dynamoelectric machine is provided with an arrangement in the form of a plurality of cooling tubes disposed in or adjacent the stator core of the machine and through which a coolant is caused to flow. The coolant tubes extend axially with respect to the rotor of the machine and are spaced around the circumference of the stator. In order to regulate the cooling efficiency and reduce the coolant pressure loss in the coolant tubes, a branching arrangement in combination with a valve arrangement is disposed in at least one of the end brackets of the machine to control the flow of coolant in parallel selectively through different combinations of cooling tubes. The branching arrangement includes a plurality of circumferentially disposed chambers which communicate with respective groups of cooling tubes in parallel, and the valve arrangement allows connection of these chambers selectively in different combinations to a coolant supply and a coolant exhaust.
    Type: Grant
    Filed: September 9, 1996
    Date of Patent: March 23, 1999
    Assignees: Hitachi, Ltd., Hitachi Car Engineering Co., Ltd.
    Inventors: Keiji Oda, Hiroshi Hamano, Suetaro Shibukawa, Osamu Koizumi, Kiyoshi Hirano