Patents by Inventor Kenji Tomohara

Kenji Tomohara 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: 9231514
    Abstract: A winding switching signal generator is configured to obtain information indicating a degree of field weakening from at least one of a current command calculator and a constant output controller, and to generate a winding switching signal for switching from a low speed rotation state to a high speed rotation state when the degree of the field weakening exceeds a predetermined condition in the low speed rotation state.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: January 5, 2016
    Assignee: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Zhenning Chen, Tomohiro Kawachi, Kenji Tomohara, Koji Higashikawa, Masashi Takenouchi
  • Patent number: 9166513
    Abstract: Provided is an inverter apparatus 20 configured to switch a current winding to an optimal winding when a rotation speed of a rotor of an AC electric motor 40 is within a hysteresis region defined by first and second switch timings for switching a state of an armature winding between a first winding and a second winding and when the current winding differs from the optimal winding.
    Type: Grant
    Filed: May 16, 2013
    Date of Patent: October 20, 2015
    Assignee: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Masashi Takenouchi, Tomohiro Kawachi, Kenji Tomohara, Koji Higashikawa
  • Patent number: 9041268
    Abstract: A rotary electric machine includes a rotor core in which first magnetic pole portions having permanent magnets and second magnetic pole portions having no permanent magnets are alternately arranged in a circumferential direction; and a stator core which is arranged to face an outer periphery of the rotor core. The rotor core is configured such that an average gap length between the stator core and the second magnetic pole portions is larger than an average gap length between the stator core and the first magnetic pole portions.
    Type: Grant
    Filed: February 13, 2013
    Date of Patent: May 26, 2015
    Assignee: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Kenji Tomohara, Akihiko Maemura
  • Publication number: 20140285055
    Abstract: A wound member for manufacturing a coil is a wound member for manufacturing a coil for manufacturing a coil wound around a slot of a stator core. The wound member for manufacturing a coil includes: a first side to be an end side at one side of a coil end disposed at an inner peripheral side of the stator core; a second side disposed opposite to the first side, the second side being to be an end side at another side of a coil end disposed at an outer peripheral side of the stator core; and a third side and a fourth side that respectively couple the first side and the second side. The first side has a length shorter than a length of the second side.
    Type: Application
    Filed: March 17, 2014
    Publication date: September 25, 2014
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Kenji TOMOHARA, Akihiko MAEMURA, Takeshi INOUE, Norimasa ADACHI, Junichi YASUKAWA
  • Publication number: 20140285056
    Abstract: A wound member for manufacturing a coil for manufacturing a coil wound around a slot of a stator core, the wound member for manufacturing a coil includes: a first side and a second side disposed opposite one another so as to be end sides of coil ends; and a third side and a fourth side that respectively couple the first side and the second side, wherein at least one of the first side and the second side is wrapped such that a side end at an outer peripheral side is shifted to an outer peripheral side to form a side end at an outer peripheral side to be an approximately flat surface when the first side and the second side become end sides of the coil ends.
    Type: Application
    Filed: March 17, 2014
    Publication date: September 25, 2014
    Applicant: Kabushiki Kaisha Yaskawa Denki
    Inventors: Kenji TOMOHARA, Akihiko MAEMURA, Takeshi INOUE, Norimasa ADACHI, Junichi YASUKAWA
  • Publication number: 20140285052
    Abstract: A coil includes: a coil main body in which one coil end in an axial direction is bent to an inner peripheral side of a stator core including a tooth having an protrusion preventing portion configured to prevent the coil from protruding to the inner peripheral side of the stator core; and a relief portion provided for a portion of the coil main body that is bent to the inner peripheral side of the stator core. The relief portion is configured to release the protrusion preventing portion of the tooth when the coil main body is inserted into a slot of the stator core in the axial direction from one coil end in the axial direction that is bent to the inner peripheral side of the stator core.
    Type: Application
    Filed: March 19, 2014
    Publication date: September 25, 2014
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Kenji TOMOHARA, Akihiko MAEMURA, Takeshi INOUE, Norimasa ADACHI, Junichi YASUKAWA
  • Publication number: 20140210397
    Abstract: Provided is an inverter apparatus 20 configured to switch a current winding to an optimal winding when a rotation speed of a rotor of an AC electric motor 40 is within a hysteresis region defined by first and second switch timings for switching a state of an armature winding between a first winding and a second winding and when the current winding differs from the optimal winding.
    Type: Application
    Filed: May 16, 2013
    Publication date: July 31, 2014
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Masashi TAKENOUCHI, Tomohiro KAWACHI, Kenji TOMOHARA, Koji HIGASHIKAWA
  • Publication number: 20140197771
    Abstract: A winding switching signal generator is configured to obtain information indicating a degree of field weakening from at least one of a current command calculator and a constant output controller, and to generate a winding switching signal for switching from a low speed rotation state to a high speed rotation state when the degree of the field weakening exceeds a predetermined condition in the low speed rotation state.
    Type: Application
    Filed: May 16, 2013
    Publication date: July 17, 2014
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Zhenning CHEN, Tomohiro KAWACHI, Kenji TOMOHARA, Koji HIGASHIKAWA, Masashi TAKENOUCHI
  • Patent number: 8760026
    Abstract: A rotor includes first and second permanent magnets provided in each magnetic pole inside a rotor core. The rotor is configured such that when a first end of the first permanent magnet located on the outer circumferential side of the rotor core and the second permanent magnet side is located at a position that faces a first end in the circumferential direction of one of teeth of a stator, a second end of the first permanent magnet located on the axis of rotation side of the rotor core and the second permanent magnet side is located at a position that faces a second end in the circumferential direction of the tooth that faces the first end of the first permanent magnet.
    Type: Grant
    Filed: February 29, 2012
    Date of Patent: June 24, 2014
    Assignee: Kabushiki Kaisha Yaskawa Denki
    Inventors: Takeo Suzuki, Akihiko Maemura, Yosuke Kawazoe, Yuto Fukuma, Kenji Tomohara
  • Patent number: 8427023
    Abstract: A rotor includes a rotor core; and first and second permanent magnets arranged in the core such that each of the first magnets corresponds to one of the second magnets and, on a cross-sectional plane of the rotor core perpendicular to a rotation axis thereof, a first line passing through the first magnet and a second line passing through the second magnet meet at a point pointing toward the rotation axis. The first and second magnets are arranged such that a straight line interconnecting the rotation axis and the point is interposed therebetween, an angle of the first magnet relative to the straight line being smaller than that of the second magnet relative to the straight line, and a width of the first magnet in the direction parallel to the first line being smaller than that of the second magnet in the direction parallel to the second line.
    Type: Grant
    Filed: October 26, 2012
    Date of Patent: April 23, 2013
    Assignee: Kabushiki Kaisha Yaskawa Denki
    Inventors: Akihiko Maemura, Kenji Tomohara, Takeo Suzuki
  • Patent number: 8319387
    Abstract: A rotor includes a rotor core; and first permanent magnets and second permanent magnets arranged in the rotor core so that, on a cross-sectional plane of the rotor core perpendicular to the rotation axis thereof, the first and second magnets corresponding to each other define the letter V having an apex pointing toward the rotation axis. The first and second magnets corresponding to each other are arranged so that a straight line interconnecting the rotation axis and the apex of the letter V is interposed therebetween, an angle of the first magnet relative to the straight line being smaller than that of the second magnet relative to the straight line, a width of the first magnet in the direction parallel to the first side of the letter V being smaller than that of the second magnet in the direction parallel to the second side of the letter V.
    Type: Grant
    Filed: January 12, 2011
    Date of Patent: November 27, 2012
    Assignee: Kabushiki Kaisha Yaskawa Denki
    Inventors: Akihiko Maemura, Kenji Tomohara, Takeo Suzuki
  • Publication number: 20120212095
    Abstract: A rotor includes first and second permanent magnets provided in each magnetic pole inside a rotor core. The rotor is configured such that when a first end of the first permanent magnet located on the outer circumferential side of the rotor core and the second permanent magnet side is located at a position that faces a first end in the circumferential direction of one of teeth of a stator, a second end of the first permanent magnet located on the axis of rotation side of the rotor core and the second permanent magnet side is located at a position that faces a second end in the circumferential direction of the tooth that faces the first end of the first permanent magnet.
    Type: Application
    Filed: February 29, 2012
    Publication date: August 23, 2012
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Takeo SUZUKI, Akihiko MAEMURA, Yosuke KAWAZOE, Yuto FUKUMA, Kenji TOMOHARA
  • Patent number: 8102092
    Abstract: Split cores comprising laminated iron cores each having formed thereon a tooth, and a yoke and a pole piece which are connected to the tooth at both ends thereof, and arranged and connected together into an annular shape to make a stator. Both ends of the yokes and both ends of the pole pieces are displaced in one circumferential direction by laminated iron core from a top laminated layer of the iron cores of the split cores to a bottom laminated layer of the iron cores or split cores.
    Type: Grant
    Filed: January 19, 2007
    Date of Patent: January 24, 2012
    Assignee: Kabushiki Kaisha Yaskawa Denki
    Inventors: Kenji Tomohara, Seiji Miyazaki, Mitsuhiro Koga, Makoto Matsumoto, Hiroshi Koga, Shinichi Sakamoto
  • Publication number: 20110169364
    Abstract: A rotor includes a rotor core; and first permanent magnets and second permanent magnets arranged in the rotor core so that, on a cross-sectional plane of the rotor core perpendicular to the rotation axis thereof, the first and second magnets corresponding to each other define the letter V having an apex pointing toward the rotation axis. The first and second magnets corresponding to each other are arranged so that a straight line interconnecting the rotation axis and the apex of the letter V is interposed therebetween, an angle of the first magnet relative to the straight line being smaller than that of the second magnet relative to the straight line, a width of the first magnet in the direction parallel to the first side of the letter V being smaller than that of the second magnet in the direction parallel to the second side of the letter V.
    Type: Application
    Filed: January 12, 2011
    Publication date: July 14, 2011
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Akihiko MAEMURA, Kenji Tomohara, Takeo Suzuki
  • Publication number: 20090026872
    Abstract: Although in a conventional permanent magnet type synchronous motor, cogging torque is reduced by displacing permanent magnets of a rotor in a circumferential direction or displacing a stator core in a circumferential direction, since the skew so produced reduces the output of the motor and moreover the winding work of windings cannot be automated to make the resulting motor highly expensive, split cores are provided which solves those problems and enables the winding work of windings to be automated so as to obtain an inexpensive and high-output motor.
    Type: Application
    Filed: January 19, 2007
    Publication date: January 29, 2009
    Applicant: KABUSHIKI KAISHA YASKAWA DENKI
    Inventors: Kenji Tomohara, Seiji Miyazaki, Mitsuhiro Koga, Makoto Matsumoto, Hiroshi Koga, Shinichi Sakamoto