Patents by Inventor Shouichi Kawamata

Shouichi Kawamata 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: 20050023920
    Abstract: A magnetic gap is provided between a permanent magnet of a rotor and an auxiliary magnet 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: September 7, 2004
    Publication date: February 3, 2005
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Keiji Oda
  • 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: 6815858
    Abstract: A permanent magnet rotating electric machine uses no skewing under a predetermined current and voltage condition to prevent torque from decreasing and to decrease pulsation torque to make the machine less vibrating and less noisy. The permanent magnet rotating electric machine includes a stator with multi-phase stator windings and a rotor with a plurality of permanent magnets internally embedded in a rotor core. The core shape of the rotor is uniform in the depth (longitudinal) direction with no skewing in the arrangement of the permanent magnets. The permanent magnets are symmetrical with respect to the rotation direction, but irregular with respect to the depth direction, for each pole. A magnetic flux generated from the between-pole permanent magnets almost equals a magnetic flux generated from the pole-center permanent magnet.
    Type: Grant
    Filed: September 18, 2002
    Date of Patent: November 9, 2004
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Takashi Yasuhara
  • 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
  • Publication number: 20040112655
    Abstract: The invention provides a hybrid electric vehicle employing a permanent magnet type dynamo-electric machine structured such that a torque at a time of reverse rotation is greater than a maximum torque output by a dynamo-electric machine when the dynamo-electric machine normally rotates. Further, the present invention provides a hybrid electric vehicle in which a dynamo-electric machine and an engine are connected to a drive shaft in series and no gear for switching between forward and backward movements is provided, wherein there is employed a permanent magnet type dynamo-electric machine structured such that a torque output by the dynamo-electric machine when the hybrid electric vehicle moves backward (the dynamo-electric machine reverse rotates) is greater than a maximum torque output by the dynamo-electric machine when the hybrid electric vehicle moves forward (the dynamo-electric machine normally rotates).
    Type: Application
    Filed: November 21, 2003
    Publication date: June 17, 2004
    Applicant: Hitachi Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Osamu Koizumi, Sanshiro Obara
  • Publication number: 20040108782
    Abstract: In order to provide a motor characterized by a high level of efficiency equal to or better than that of using the silicon steel plate, achieved by easy production method and reduced core loss, which result from reduction in the manpower for production by using the sintered metal or powdered iron core in at least one of the stator and rotor, the present invention provides a motor comprising a stator and a rotor wherein either one of said stator or rotor has a magnet, and the other has a magnetic substance. This motor is further characterized in that the main magnetic flux flowing between the stator and rotor changes in the three-dimensional directions according to the magnetic structure of this motor, and at least part of said magnetic substance is composed of an aggregate of magnetic powder.
    Type: Application
    Filed: August 15, 2003
    Publication date: June 10, 2004
    Inventors: Yuji Enomto, Noriaki Hino, Shouichi Kawamata, Kazumasa Ide, Yasuo Matsuda, Toshihiko Sakai
  • 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
  • Patent number: 6661147
    Abstract: An rotary electric machine 1 comprises stator 2 having a stator core 4 wounded with stator windings 5 and a rotor 3 having a rotor core 7 rotatable and opposite to the stator core 4 through a gap. The rotor core 4 of the roraty electric machine 1 is composed of a plurality of projecting pole magnetic core portions 73 arranged in a side of the gap and along the circumferential direction and a plurality of rotor yoke portions 76 for forming a magnetic path conducting magnetic fluxes of each of the projecting pole magnetic core portions 73, and the rotor core is divided in the circumferential direction on a unit of each of the projecting pole magnetic core portions 73 and each of the rotor yokes 76 opposite to each of the projecting pole magnetic core portions 73. It is possible to provide a rotary electric machine which is high in material use factor at manufacturing a rotor core and small in size and light in weight, and to provide an electric vehicle using the rotary electric machine.
    Type: Grant
    Filed: March 7, 2002
    Date of Patent: December 9, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Takashi Kobayashi
  • 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
  • Patent number: 6528920
    Abstract: At least one groove and two grooves extending toward an axial direction of a rotor and is provided on an outer periphery of a rotor iron core or at least one hole is provided in the rotor iron core. By providing the groove and the two grooves on the outer periphery of the rotor iron core or by providing the hole in the rotor iron core, cogging torque is generated to negate the cogging torque which is generated according to the magnetic fluctuation between the magnetic field of the permanent magnets and a stator. As a result, the overall cogging toque in a permanent magnet type rotary machine is reduced.
    Type: Grant
    Filed: March 14, 2001
    Date of Patent: March 4, 2003
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi
  • Publication number: 20020153795
    Abstract: A permanent magnet type electric rotating machine comprises a stator having a salient-pole concentrated winding, and a rotor disposed with a rotational gap, and having a plurality of permanent magnets arranged and fixed in a circumferential direction inside, and an auxiliary salient pole provided between the permanent magnets. A ratio of the number of poles for the rotor and the number of slots for the stator is 2:3 and, when a slot pitch of the stator is &tgr;s (electrical angle), an angle &thgr; (electrical angle) made by a circumferential width of the permanent magnet in the surface of the stator side with an axis of the rotor is set at &thgr;≈n×&tgr;s/2+8×m (n=1 or 2, and m=1, 2 or 3). Thus, pulsation torque, cogging torque or the waveform distortion of a no-load induced voltage is selectively reduced as occasion demands.
    Type: Application
    Filed: June 12, 2002
    Publication date: October 24, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Osamu Koizumi, Sanshiro Obara
  • 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: 6452302
    Abstract: An rotary electric machine 1 comprises stator 2 having a stator core 4 wounded with stator windings 5 and a rotor 3 having a rotor core 7 rotatable and opposite to the stator core 4 through a gap. The rotor core 4 of the roraty electric machine 1 is composed of a plurality of projecting pole magnetic core portions 73 arranged in a side of the gap and along the circumferential direction and a plurality of rotor yoke portions 76 for forming a magnetic path conducting magnetic fluxes of each of the projecting pole magnetic core portions 73, and the rotor core is divided in the circumferential direction on a unit of each of the projecting pole magnetic core portions 73 and each of the rotor yokes 76 opposite to each of the projecting pole magnetic core portions 73. It is possible to provide a rotary electric machine which is high in material use factor at manufacturing a rotor core and small in size and light in weight, and to provide an electric vehicle using the rotary electric machine.
    Type: Grant
    Filed: September 21, 1999
    Date of Patent: September 17, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Takashi Kobayashi
  • 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
  • Publication number: 20020112904
    Abstract: A hybrid electric vehicle has a permanent magnet type dynamo-electric machine whose torque during reverse rotation is greater than its maximum torque in forward rotation. The dynamo-electric machine is connected in series with an engine and a drive shaft, and no gear is provided for switching between forward and backward movements. The dynamo-electric machine has a stator with a stator iron core around which a stator coil is wound, and a rotor arranged in the stator at a rotational gap and having a plurality of permanent magnets arranged and fixed within a rotor iron core in a peripheral direction. The ratio between a maximum torque output by the dynamo-electric machine when the dynamo-electric machine normally rotates and a torque output by the dynamo-electric machine when reverse rotating is in the range of 1:1.05-1.2, wherein the torque in reverse rotation is greater.
    Type: Application
    Filed: February 8, 2002
    Publication date: August 22, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Osamu Koizumi, Sanshiro Obara
  • Patent number: 6429565
    Abstract: A permanent magnet type electric rotating machine comprises a stator having a salient-pole concentrated winding, and a rotor disposed with a rotational gap, and having a plurality of permanent magnets arranged and fixed in a circumferential direction inside, and an auxiliary salient pole provided between the permanent magnets. A ratio of the number of poles for the rotor and the number of slots for the stator is 2:3 and, when a slot pitch of the stator is &tgr;s (electrical angle), an angle &thgr; (electrical angle) made by a circumferential width of the permanent magnet in the surface of the stator side with an axis of the rotor is set at &thgr;≈n×&tgr;s/2+8×m (n=1 or 2, and m=1, 2 or 3). Thus, pulsation torque, cogging torque or the waveform distortion of a no-load induced voltage is selectively reduced as occasion demands.
    Type: Grant
    Filed: September 1, 2000
    Date of Patent: August 6, 2002
    Assignee: Hitachi, Ltd.
    Inventors: Yutaka Matsunobu, Fumio Tajima, Shouichi Kawamata, Osamu Koizumi, Sanshiro Obara
  • Publication number: 20020089251
    Abstract: An rotary electric machine 1 comprises stator 2 having a stator core 4 wounded with stator windings 5 and a rotor 3 having a rotor core 7 rotatable and opposite to the stator core 4 through a gap. The rotor core 4 of the roraty electric machine 1 is composed of a plurality of projecting pole magnetic core portions 73 arranged in a side of the gap and along the circumferential direction and a plurality of rotor yoke portions 76 for forming a magnetic path conducting magnetic fluxes of each of the projecting pole magnetic core portions 73, and the rotor core is divided in the circumferential direction on a unit of each of the projecting pole magnetic core portions 73 and each of the rotor yokes 76 opposite to each of the projecting pole magnetic core portions 73. It is possible to provide a rotary electric machine which is high in material use factor at manufacturing a rotor core and small in size and light in weight, and to provide an electric vehicle using the rotary electric machine.
    Type: Application
    Filed: March 7, 2002
    Publication date: July 11, 2002
    Applicant: Hitachi, Ltd.
    Inventors: Fumio Tajima, Yutaka Matsunobu, Shouichi Kawamata, Suetaro Shibukawa, Osamu Koizumi, Takashi Kobayashi
  • 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