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).
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Publication number: 20240123943Abstract: 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: ApplicationFiled: June 1, 2023Publication date: April 18, 2024Applicant: MITSUBA CorporationInventors: Ryo OHORI, Toshiyuki AMAGASA, Masahiro YAMADA, Atsushi MOCHIDA, Tamotsu IWAZAKI
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Publication number: 20240106377Abstract: 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: ApplicationFiled: June 18, 2023Publication date: March 28, 2024Applicant: MITSUBA CorporationInventors: RYO OHORI, TOSHIYUKI AMAGASA, MASAHIRO YAMADA, ATSUSHI MOCHIDA, TAMOTSU IWAZAKI
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Patent number: 10644623Abstract: 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: GrantFiled: December 1, 2016Date of Patent: May 5, 2020Assignee: Mitsuba CorporationInventors: Tamotsu Iwazaki, Toru Furusawa, Takashi Hoshino, Tomofumi Kobayashi
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Patent number: 10513288Abstract: 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: GrantFiled: September 29, 2016Date of Patent: December 24, 2019Assignee: Mitsuba CorporationInventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
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Publication number: 20180358912Abstract: 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: ApplicationFiled: December 1, 2016Publication date: December 13, 2018Applicants: Mitsuba Corporation, Mitsuba CorporationInventors: Tamotsu Iwazaki, Toru Furusawa, Takashi Hoshino, Tomofumi Kobayashi
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Publication number: 20180244306Abstract: 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: ApplicationFiled: September 29, 2016Publication date: August 30, 2018Inventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
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Publication number: 20180248501Abstract: 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: ApplicationFiled: April 6, 2016Publication date: August 30, 2018Inventors: Takashi Hoshino, Tamotsu Iwazaki
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Publication number: 20180237057Abstract: 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: ApplicationFiled: September 29, 2016Publication date: August 23, 2018Inventors: Hiroaki Tanikawa, Shuichi Matsuhashi, Toru Furusawa, Tamotsu Iwazaki
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Patent number: 9923494Abstract: 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: GrantFiled: July 24, 2017Date of Patent: March 20, 2018Assignee: Mitsuba CorporationInventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Publication number: 20170324357Abstract: 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: ApplicationFiled: July 24, 2017Publication date: November 9, 2017Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Patent number: 9735717Abstract: 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: GrantFiled: April 19, 2017Date of Patent: August 15, 2017Assignee: Mitsuba CorporationInventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Publication number: 20170222581Abstract: 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: ApplicationFiled: April 19, 2017Publication date: August 3, 2017Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Patent number: 9660559Abstract: 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: GrantFiled: April 16, 2013Date of Patent: May 23, 2017Assignee: Mitsuba CorporationInventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Publication number: 20160241108Abstract: 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: ApplicationFiled: September 24, 2013Publication date: August 18, 2016Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki
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Patent number: 9180838Abstract: 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: GrantFiled: June 26, 2012Date of Patent: November 10, 2015Assignee: Mitsuba CorporationInventors: Toshiyuki Amagasa, Hiroto Tanaka, Tamotsu Iwazaki
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Patent number: 9093931Abstract: 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: GrantFiled: June 1, 2012Date of Patent: July 28, 2015Assignee: Mitsuba CorporationInventors: Shinji Shibuya, Tamotsu Iwazaki, Sadami Hino
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Publication number: 20150082575Abstract: 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: ApplicationFiled: April 16, 2013Publication date: March 26, 2015Inventors: Masaaki Kimura, Hiroto Tanaka, Tamotsu Iwazaki, Tomohiko Annaka, Naoki Kojima, Junya Kitazawa
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Publication number: 20140139148Abstract: 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: ApplicationFiled: June 26, 2012Publication date: May 22, 2014Inventors: Toshiyuki Amagasa, Hiroto Tanaka, Tamotsu Iwazaki
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Publication number: 20130043817Abstract: 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: ApplicationFiled: June 1, 2012Publication date: February 21, 2013Applicant: MITSUBA CORPORATIONInventors: Shinji SHIBUYA, Tamotsu IWAZAKI, Sadami HINO