Patents by Inventor Kohei Murota
Kohei Murota 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: 20240235334Abstract: A rotating electrical machine includes: a three-phase coil including a U-phase coil, a V-phase coil, and a W-phase coil each formed of a flat wire; a neutral point bus bar forming a neutral point of the three-phase coil and formed of a conductive plate; and a temperature detector configured to detect a temperature of the three-phase coil. The neutral point bus bar is formed in an arc shape along an outer periphery of the three-phase coil. One end of one coil in the three-phase coil is connected to a vicinity of a center of the neutral point bus bar in a circumferential direction thereof. One end of each of remaining two coils in the three-phase coil is connected to a vicinity of an end of the neutral point bus bar in the circumferential direction.Type: ApplicationFiled: May 17, 2021Publication date: July 11, 2024Applicant: NISSAN MOTOR CO., LTD.Inventors: Shunta SUGANO, Toru NAKADA, Kohei MUROTA, Tatsuya IMAI, Masanobu ABE, Masahide KIMURA
-
Patent number: 10715077Abstract: A method of controlling a motor having windings of a plurality of phases includes an estimation step of calculating a current vector norm from d-axis current and q-axis current flowing in the motor, calculating power loss from the current vector norm and the entire heat resistance of the motor, and estimating the maximum temperature of the windings of the plurality of phases based on the power loss and a transfer function having first or higher-order transfer characteristics, in the case where the motor is in a low rotation state, and a limiting step of limiting input power based on the maximum temperature estimated in the estimation step.Type: GrantFiled: November 1, 2016Date of Patent: July 14, 2020Assignee: Nissan Motor Co., Ltd.Inventors: Ken Itou, Kohei Murota, Tomoaki Mori, Naoki Takahashi, Hiromichi Kawamura
-
Publication number: 20190305713Abstract: A method of controlling a motor having windings of a plurality of phases includes an estimation step of calculating a current vector norm from d-axis current and q-axis current flowing in the motor, calculating power loss from the current vector norm and the entire heat resistance of the motor, and estimating the maximum temperature of the windings of the plurality of phases based on the power loss and a transfer function having first or higher-order transfer characteristics, in the case where the motor is in a low rotation state, and a limiting step of limiting input power based on the maximum temperature estimated in the estimation step.Type: ApplicationFiled: November 1, 2016Publication date: October 3, 2019Applicant: Nissan Motor Co., Ltd.Inventors: Ken Itou, Kohei Murota, Tomoaki Mori, Naoki Takahashi, Hiromichi Kawamura
-
Patent number: 10241080Abstract: A magnet evaluation device is provided for evaluating a magnet having at least two magnetic pieces bonded to an insulating material sandwiched between two adjacent ones of the magnetic pieces. The magnet evaluation device has an excitation coil and a detection coil. The excitation coil is configured to generate a magnetic field that has a size in a range that corresponds to a region including the insulating material. The detection coil has a coil diameter that is smaller than a length of one of the magnetic pieces in a direction in which the magnetic pieces are aligned.Type: GrantFiled: October 25, 2012Date of Patent: March 26, 2019Assignee: Nissan Motor Co., Ltd.Inventors: Tadashi Komai, Yutaka Suzuki, Kiyoshi Yoshida, Kohei Murota, Kunitomo Ishiguro, Yasuhisa Koike, Hideo Mogi
-
Patent number: 9780612Abstract: A rotor structure for an electric rotating machine has a rotor, a plurality of strip-shaped permanent magnets which are arranged in a circumferential direction of the rotor, each of which penetrates the rotor in an axial direction of the rotor, flux barriers which are air gaps provided at positions corresponding to width-direction end portions of the permanent magnets to face the width-direction end portions of the permanent magnets, and demagnetization prevention holes, each of which is provided at a position in a vicinity of a corresponding one of the flux barriers and on an opposite side of the flux barrier from a stator and configured to reduce demagnetization at a corresponding one of the width-direction end portions of the permanent magnets.Type: GrantFiled: February 25, 2015Date of Patent: October 3, 2017Assignee: NISSAN MOTOR CO., LTD.Inventors: Kohei Murota, Tohru Nakada
-
Publication number: 20170085142Abstract: A rotor structure for an electric rotating machine has a rotor, a plurality of strip-shaped permanent magnets which are arranged in a circumferential direction of the rotor, each of which penetrates the rotor in an axial direction of the rotor, flux barriers which are air gaps provided at positions corresponding to width-direction end portions of the permanent magnets to face the width-direction end portions of the permanent magnets, and demagnetization prevention holes, each of which is provided at a position in a vicinity of a corresponding one of the flux barriers and on an opposite side of the flux barrier from a stator and configured to reduce demagnetization at a corresponding one of the width-direction end portions of the permanent magnets.Type: ApplicationFiled: February 25, 2015Publication date: March 23, 2017Applicant: Nissan Motor Co., Ltd.Inventors: Kohei Murota, Tohru Nakada
-
Patent number: 9337692Abstract: A flux barrier includes a radially outer proximate part and a radially inner proximate part that are a rotor radially outer side surface and a rotor radially inner side surface extending from a communicating part, at least one of the radially outer proximate part and the radially inner proximate part is connected to an end part of a magnet fixing part of a magnet hole in an inward direction of the magnet hole, and a projecting part projecting in an inward direction of the flux barrier is provided on at least one of the radially outer proximate part and the radially inner proximate part connected to the magnet fixing part. A constricted part in which a width of the flux barrier is narrower than on a side closer to the communicating part than the projecting part is formed by the projecting part.Type: GrantFiled: October 12, 2012Date of Patent: May 10, 2016Assignee: NISSAN MOTOR CO., LTD.Inventors: Kohei Murota, Tohru Nakada, Shunji Oki
-
Publication number: 20140312889Abstract: A magnet evaluation device is provided for evaluating a magnet having at least two magnetic pieces bonded to an insulating material sandwiched between two adjacent ones of the magnetic pieces. The magnet evaluation device has an excitation coil and a detection coil. The excitation coil is configured to generate a magnetic field that has a size in a range that corresponds to a region including the insulating material. The detection coil has a coil diameter that is smaller than a length of one of the magnetic pieces in a direction in which the magnetic pieces are aligned.Type: ApplicationFiled: October 25, 2012Publication date: October 23, 2014Applicant: Nissan Motor Co., Ltd.Inventors: Tadashi Komai, Yutaka Suzuki, Kiyoshi Yoshida, Kohei Murota, Kunitomo Ishiguro, Yasuhisa Koike, Hideo Mogi
-
Publication number: 20140292133Abstract: A flux barrier includes a radially outer proximate part and a radially inner proximate part that are a rotor radially outer side surface and a rotor radially inner side surface extending from a communicating part, at least one of the radially outer proximate part and the radially inner proximate part is connected to an end part of a magnet fixing part of a magnet hole in an inward direction of the magnet hole, and a projecting part projecting in an inward direction of the flux barrier is provided on at least one of the radially outer proximate part and the radially inner proximate part connected to the magnet fixing part. A constricted part in which a width of the flux barrier is narrower than on a side closer to the communicating part than the projecting part is formed by the projecting part.Type: ApplicationFiled: October 12, 2012Publication date: October 2, 2014Applicant: NISSAN MOTOR CO., LTD.Inventors: Kohei Murota, Tohru Nakada, Shunji Oki