Patents by Inventor Tamotsu IWAZAKI

Tamotsu IWAZAKI 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: 20240123943
    Abstract: A motor control device includes a driving control part and an upper limit value setting part. The driving control part controls motor driving by switching between a first driving mode and a second driving mode, and controls an output duty ratio so as not to exceed a duty ratio upper limit value. The upper limit value setting part sets, as the duty ratio upper limit value, a low rotation duty ratio upper limit value, a maximum duty ratio upper limit value corresponding to a maximum output value, and an upper limit value of a transition period from the low rotation duty ratio upper limit value to the maximum duty ratio upper limit value, and changes slope information indicating a change amount in the upper limit value of the transition period according to the driving mode when switching between the first driving mode and the second driving mode.
    Type: Application
    Filed: June 1, 2023
    Publication date: April 18, 2024
    Applicant: MITSUBA Corporation
    Inventors: Ryo OHORI, Toshiyuki AMAGASA, Masahiro YAMADA, Atsushi MOCHIDA, Tamotsu IWAZAKI
  • Publication number: 20240106377
    Abstract: A motor control device which controls a motor having an output shaft includes a vehicle speed detection part and a driving control part. The vehicle speed detection part detects a vehicle speed, which is a traveling speed of a vehicle mounted with the motor. Based on the vehicle speed detected by the vehicle speed detection part, the driving control part performs control of switching between a first driving mode which drives the motor, and a second driving mode in which a number of revolutions of the output shaft and an output of the motor are higher than in the first driving mode.
    Type: Application
    Filed: June 18, 2023
    Publication date: March 28, 2024
    Applicant: MITSUBA Corporation
    Inventors: RYO OHORI, TOSHIYUKI AMAGASA, MASAHIRO YAMADA, ATSUSHI MOCHIDA, TAMOTSU IWAZAKI
  • Patent number: 10644623
    Abstract: Based on an output signal, among a plurality of switching elements, an element control part outputs a PWM signal having a maximum duty ratio to a pair of switching elements that drive a first coil among a plurality of coils to a high level, outputs a PWM signal having a minimum duty ratio to a pair of switching elements that are connected to each other in series and that drive a second coil among the plurality of coils to a low level, and outputs a PWM signal having a medium duty ratio between the maximum duty ratio of the PWM signal and the minimum duty ratio of the PWM signal to a pair of switching elements that are connected to each other in series and that drive a third coil among the plurality of coils.
    Type: Grant
    Filed: December 1, 2016
    Date of Patent: May 5, 2020
    Assignee: Mitsuba Corporation
    Inventors: Tamotsu Iwazaki, Toru Furusawa, Takashi Hoshino, Tomofumi Kobayashi
  • Patent number: 10513288
    Abstract: An electric power steering device includes an electric motor driven by electric power from a power supply and configured to apply an assisting force to a steering shaft, a booster circuit connected to the power supply and configured to supply a boosting voltage to the electric motor, and a control device configured to manage at least one of a boosting duration time that is a continuous operation time of the booster circuit and a boosting prohibition time that is a continuous stoppage time of the booster circuit on the basis of a boosted electric power value during an operation of the booster circuit.
    Type: Grant
    Filed: September 29, 2016
    Date of Patent: December 24, 2019
    Assignee: Mitsuba Corporation
    Inventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
  • Publication number: 20180358912
    Abstract: Based on an output signal, among a plurality of switching elements, an element control part outputs a PWM signal having a maximum duty ratio to a pair of switching elements that drive a first coil among a plurality of coils to a high level, outputs a PWM signal having a minimum duty ratio to a pair of switching elements that are connected to each other in series and that drive a second coil among the plurality of coils to a low level, and outputs a PWM signal having a medium duty ratio between the maximum duty ratio of the PWM signal and the minimum duty ratio of the PWM signal to a pair of switching elements that are connected to each other in series and that drive a third coil among the plurality of coils.
    Type: Application
    Filed: December 1, 2016
    Publication date: December 13, 2018
    Applicants: Mitsuba Corporation, Mitsuba Corporation
    Inventors: Tamotsu Iwazaki, Toru Furusawa, Takashi Hoshino, Tomofumi Kobayashi
  • Publication number: 20180244306
    Abstract: An electric power steering device includes an electric motor driven by electric power from a power supply and configured to apply an assisting force to a steering shaft, a booster circuit connected to the power supply and configured to supply a boosting voltage to the electric motor, and a control device configured to manage at least one of a boosting duration time that is a continuous operation time of the booster circuit and a boosting prohibition time that is a continuous stoppage time of the booster circuit on the basis of a boosted electric power value during an operation of the booster circuit.
    Type: Application
    Filed: September 29, 2016
    Publication date: August 30, 2018
    Inventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
  • Publication number: 20180248501
    Abstract: In a motor drive apparatus, the brushless motor has a three-phase motor structure, the Hall sensor detects a magnetic flux change signal in an operation of the brushless motor, the control unit obtains a rotor rotation number of the brushless motor (11) based on the magnetic flux change signal, calculates a predetermined electric angle even when the rotor rotation number is changed, and causes the gate driver to output a PWM signal by which a power distribution timing to each phase of the brushless motor is switched at the predetermined electric angle, and the inverter sinusoidally changes and supplies a voltage supply to a stator coil of the brushless motor based on the PWM signal.
    Type: Application
    Filed: April 6, 2016
    Publication date: August 30, 2018
    Inventors: Takashi Hoshino, Tamotsu Iwazaki
  • Publication number: 20180237057
    Abstract: An electric power steering device includes an electric motor driven by electric power from a power supply and configured to apply an assisting force to a steering shaft, a booster circuit connected to the power supply and configured to supply a boosting voltage to the electric motor, and a boosting control unit configured to determine a starting condition under which the start of boosting of the booster circuit is controlled on the basis of an angular acceleration of the electric motor, and start the boosting of the booster circuit when the determined starting condition is satisfied.
    Type: Application
    Filed: September 29, 2016
    Publication date: August 23, 2018
    Inventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
  • Patent number: 9923494
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Grant
    Filed: July 24, 2017
    Date of Patent: March 20, 2018
    Assignee: Mitsuba Corporation
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Publication number: 20170324357
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Application
    Filed: July 24, 2017
    Publication date: November 9, 2017
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Patent number: 9735717
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Grant
    Filed: April 19, 2017
    Date of Patent: August 15, 2017
    Assignee: Mitsuba Corporation
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Publication number: 20170222581
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Application
    Filed: April 19, 2017
    Publication date: August 3, 2017
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Patent number: 9660559
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Grant
    Filed: April 16, 2013
    Date of Patent: May 23, 2017
    Assignee: Mitsuba Corporation
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Publication number: 20160241108
    Abstract: A magnet 34 for the rotating shaft (first magnet, second magnet) is installed on the extended portion of the rotating shaft 33b in the gear housing 41, and Hall ICs 65a to 65c for the rotating shaft (first sensor, second sensor) are formed on the control board 60 inside the gear housing 41 so as to face the magnet 34 for the rotating shaft. The Hall ICs 65a to 65c for the rotating shaft are adapted to detect the rotation position of the rotating shaft 33b relative to the stator 32, that is, the rotation position of the rotor 33 relative to the stator 32, and the Hall ICs 65a to 65c for the rotating shaft are adapted to detect the rotation number of the rotating shaft 33b.
    Type: Application
    Filed: September 24, 2013
    Publication date: August 18, 2016
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki
  • Patent number: 9180838
    Abstract: A motor control device is provided which controls a motor by performing switching between forward rotation and reverse rotation so as to cause an object to be controlled to reciprocate, the motor control device including a lead angle map storage unit configured to store a lead angle map in which a motor rotation speed and a lead angle to be set are associated for each of the forward rotation and the reverse rotation, a target rotation speed-setting unit configured to set a target rotation speed of the motor based on an input signal from outside, a lead angle-setting unit configured to obtain the lead angle associated with the set target rotation speed by referring to the lead angle map and set the lead angle as a lead angle of the motor, and a driving control unit configured to control rotation of the motor so as to achieve the set target rotation speed and the set lead angle.
    Type: Grant
    Filed: June 26, 2012
    Date of Patent: November 10, 2015
    Assignee: Mitsuba Corporation
    Inventors: Toshiyuki Amagasa, Hiroto Tanaka, Tamotsu Iwazaki
  • Patent number: 9093931
    Abstract: A driving apparatus including an inverter unit for energizing the coil by switching ON and OFF of the switching element, an energization pattern determination unit for selecting a plurality of energization patterns, each of which indicates a direction of a current that flows through the coil, one by one when driving of a motor is started, and energizing the coil by switching ON and OFF of the switching element based on a selected energization pattern at a duty ratio corresponding to a value of a maximum current capable of being supplied by the power supply apparatus, a current applied time measurement unit for measuring an energization time, which is a time until a value of the current flowing through the coil reaches a predetermined target current value for each energization pattern, and a rotor stop position estimation unit for estimating a position at which the rotor stops.
    Type: Grant
    Filed: June 1, 2012
    Date of Patent: July 28, 2015
    Assignee: Mitsuba Corporation
    Inventors: Shinji Shibuya, Tamotsu Iwazaki, Sadami Hino
  • Publication number: 20150082575
    Abstract: A brushless motor comprises: a stator 21 having armature coils 21a, 21b, and 21c; a rotor 22 which is rotated by a revolving magnetic field; and a switching element 30a, wherein the brushless motor has a rotation number control unit 33 which switches between low-speed and high-speed mode, wherein in the low-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at predetermined energization timing and controls a duty ratio to control the rotation number of the rotor 22, and in the high-speed mode, the rotation number control unit 33 supplies current to the armature coils 21a, 21b, and 21c at energization timing advanced from the energization timing for the low-speed mode, thereby performing field weakening control of weakening the revolving magnetic field from that of the low-speed mode to control the rotation number of the rotor 22.
    Type: Application
    Filed: April 16, 2013
    Publication date: March 26, 2015
    Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
  • Publication number: 20140139148
    Abstract: A motor control device is provided which controls a motor by performing switching between forward rotation and reverse rotation so as to cause an object to be controlled to reciprocate, the motor control device including a lead angle map storage unit configured to store a lead angle map in which a motor rotation speed and a lead angle to be set are associated for each of the forward rotation and the reverse rotation, a target rotation speed-setting unit configured to set a target rotation speed of the motor based on an input signal from outside, a lead angle-setting unit configured to obtain the lead angle associated with the set target rotation speed by referring to the lead angle map and set the lead angle as a lead angle of the motor, and a driving control unit configured to control rotation of the motor so as to achieve the set target rotation speed and the set lead angle.
    Type: Application
    Filed: June 26, 2012
    Publication date: May 22, 2014
    Inventors: Toshiyuki Amagasa, Hiroto Tanaka, Tamotsu Iwazaki
  • Publication number: 20130043817
    Abstract: A driving apparatus including an inverter unit for energizing the coil by switching ON and OFF of the switching element, an energization pattern determination unit for selecting a plurality of energization patterns, each of which indicates a direction of a current that flows through the coil, one by one when driving of a motor is started, and energizing the coil by switching ON and OFF of the switching element based on a selected energization pattern at a duty ratio corresponding to a value of a maximum current capable of being supplied by the power supply apparatus, a current applied time measurement unit for measuring an energization time, which is a time until a value of the current flowing through the coil reaches a predetermined target current value for each energization pattern, and a rotor stop position estimation unit for estimating a position at which the rotor stops.
    Type: Application
    Filed: June 1, 2012
    Publication date: February 21, 2013
    Applicant: MITSUBA CORPORATION
    Inventors: Shinji SHIBUYA, Tamotsu IWAZAKI, Sadami HINO