Patents by Inventor Shigeki Miyaji
Shigeki Miyaji 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: 20220294313Abstract: To provide a motor inhibiting emission of electromagnetic noise (EMC) to the outside and a rotary apparatus including the motor. The rotary apparatus of the present disclosure includes: a housing; a motor arranged inside the housing; a circuit board arranged inside the housing and electrically connected to the motor; and a flexible wiring board electrically connecting the motor to the circuit board, the motor including a frame formed with a conductive member, the frame electrically connected via the flexible wiring board to a ground of the circuit board.Type: ApplicationFiled: May 31, 2022Publication date: September 15, 2022Inventors: Haruka MIYAJI, Kazuo TAKADA, Shigeki MIYAJI, Takayuki MATSUI
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Patent number: 11381139Abstract: To provide a motor inhibiting emission of electromagnetic noise (EMC) to the outside and a rotary apparatus including the motor. The rotary apparatus (10) of the present disclosure includes: a housing (20); a motor (40) arranged inside the housing (20); a circuit board (50) arranged inside the housing (20) and electrically connected to the motor (40); and a flexible wiring board (44) electrically connecting the motor (40) to the circuit board (50), the motor (40) including a frame (41a) formed with a conductive member, the frame (41a) electrically connected via the flexible wiring board (44) to a ground of the circuit board (50).Type: GrantFiled: February 22, 2019Date of Patent: July 5, 2022Assignee: MINEBEA MITSUMI INC.Inventors: Haruka Miyaji, Kazuo Takada, Shigeki Miyaji, Takayuki Matsui
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Patent number: 11139763Abstract: A motor drive control device has a controller and a driver. The controller generates a control signal for controlling driving of a two-phase stepping motor so as to alternately repeat one-phase excitation in which a coil of one phase in coils of two phases of the two-phase stepping motor is excited and two-phase excitation in which the coils of two phases in the coils of the two phases are excited. The driver drives the coils of the two phases, based on the control signal. The controller determines, based on a back electromotive force generated in the coil that was not excited during the one-phase excitation, a period of performing the one-phase excitation, and determines, based on the period of the one-phase excitation performed before the two-phase excitation, a period of performing the two-phase excitation.Type: GrantFiled: July 27, 2020Date of Patent: October 5, 2021Assignee: MINEBEA MITSUMI INC.Inventors: Haruka Miyaji, Kei Yamazaki, Takayuki Matsui, Kazuo Takada, Shigeki Miyaji, Ayaka Shimada
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Publication number: 20210199470Abstract: A novel technology for detecting an absolute position of a target object by using Hall elements is provided. A magnetic detection unit (2) includes two Hall elements (a first Hall element H1 and a second Hall element H2). The Hall elements are connected in series to each other on an input side of each of the Hall elements.Type: ApplicationFiled: April 10, 2019Publication date: July 1, 2021Inventors: Tomoyuki KITAGAWA, Shigeki MIYAJI
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Patent number: 11005400Abstract: In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device (100) includes an H bridge circuit (20) and control means for driving a switching element of the H bridge circuit (20) with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52°, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52° and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.Type: GrantFiled: May 30, 2018Date of Patent: May 11, 2021Assignee: MINEBEA MITSUMI INC.Inventors: Kei Yamazaki, Tetsuya Seki, Shigeki Miyaji
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Publication number: 20210044229Abstract: A motor drive control device has a controller and a driver. The controller generates a control signal for controlling driving of a two-phase stepping motor so as to alternately repeat one-phase excitation in which a coil of one phase in coils of two phases of the two-phase stepping motor is excited and two-phase excitation in which the coils of two phases in the coils of the two phases are excited. The driver drives the coils of the two phases, based on the control signal. The controller determines, based on a back electromotive force generated in the coil that was not excited during the one-phase excitation, a period of performing the one-phase excitation, and determines, based on the period of the one-phase excitation performed before the two-phase excitation, a period of performing the two-phase excitation.Type: ApplicationFiled: July 27, 2020Publication date: February 11, 2021Inventors: Haruka MIYAJI, Kei YAMAZAKI, Takayuki MATSUI, Kazuo TAKADA, Shigeki MIYAJI, Ayaka SHIMADA
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Patent number: 10615725Abstract: In order to prevent erroneous detection of motor step-out even when the rotational speed of the motor crosses a resonance region of the motor under acceleration and/or deceleration, a motor control device (10) includes a control unit for performing control so as to apply a pulse voltage modulated in pulse width to each of coils of plural phases equipped in a motor (20) and periodically switch the phases of the coil currents flowing through the coils of the plural phases, a back electromotive force measuring unit (126) for providing a stop period for temporarily stopping application of the pulse voltage to a coil of any one phase out of the coils of the plural phases when the direction of a coil current flowing through the coil of the phase switches, and measuring back electromotive force induced in the coil during the stop period, and a step-out state detecting unit for detecting a step-out state when the rotational speed of the motor (20) is not in a resonance region of the motor (20) and the back electromotType: GrantFiled: February 21, 2019Date of Patent: April 7, 2020Assignee: MINEBEA MITSUMI INC.Inventors: Shigeki Miyaji, Hidetoshi Hijikata, Kazuo Takada
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Publication number: 20200083827Abstract: In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device (100) includes an H bridge circuit (20) and control means for driving a switching element of the H bridge circuit (20) with a PWM signal and for setting a charge mode, a fast attenuation mode, or a slow attenuation mode for a motor coil. In a range from an electrical angle where the reference current value starts descending to an electrical angle of +52°, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52° and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit (20) every PWM cycle to the charge mode and, if the motor current exceeds the reference current value, then the control means switches it to the fast attenuation mode and further to the slow attenuation mode.Type: ApplicationFiled: May 30, 2018Publication date: March 12, 2020Inventors: Kei YAMAZAKI, Tetsuya SEKI, Shigeki MIYAJI
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Patent number: 10498270Abstract: A control device for a stepping motor gradually increases an absolute value of the excitation current in phase A from when the start until the end of the hold period such that the amount of change in the excitation current per unit time is smaller than or equal to a first predetermined value. From the start of the hold period until a predetermined time elapses, an absolute value of the excitation current in phase B gradually increases such that the amount of change in the excitation current per unit time is smaller than or equal to the first predetermined value. By the end of the hold period after the predetermined time has elapsed, the excitation current in phase B reaches zero. When the hold period ends, one-phase excitation operation starts and the excitation current flows in phase A first with the same polarity as at the end of the hold period.Type: GrantFiled: April 5, 2018Date of Patent: December 3, 2019Assignee: MINEBEA MITSUMI INC.Inventors: Koichi Takeda, Kazuo Takada, Shigeki Miyaji, Kei Yamazaki
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Patent number: 10498284Abstract: A motor drive controller includes: a control circuit that controls an AC current flowing in a motor; a frequency modulation unit that frequency-modulates a speed of the motor when the motor is driven at a predetermined speed; and a current effective value controller that decreases an effective value of the AC current flowing in the motor as the speed of the motor modulated by the frequency modulation unit becomes closer to a resonant frequency of the motor.Type: GrantFiled: March 15, 2016Date of Patent: December 3, 2019Assignee: Minebea Co., Ltd.Inventors: Shigeki Miyaji, Takayuki Matsui, Tetsuya Seki
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Patent number: 10408868Abstract: In accordance with one aspect of the present disclosure, a motor drive control device is a motor drive control device performing PWM (Pulse Width Modulation) control of a motor, wherein harmonics of a fundamental frequency for PWM control of the motor are included in noise occurring from the motor; the fundamental frequency for PWM control is larger than a frequency corresponding to a bandwidth of a predetermined radio frequency band a communication apparatus uses; and frequencies of continuous harmonic components of the fundamental frequency for PWM control appear before and after the predetermined radio frequency band.Type: GrantFiled: March 6, 2018Date of Patent: September 10, 2019Assignee: MINEBEA MITSUMI INC.Inventors: Shigeki Miyaji, Kazuo Takada, Kei Yamazaki
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Patent number: 10331571Abstract: An address control circuit includes a setting terminal connectable to a ground potential, a time constant setting circuit connected to the setting terminal, and a control unit connected to the time constant setting circuit and configured to set an address for serial communication. The time constant setting circuit includes a resistive element disposed between the setting terminal and the control unit and configured to protect the control unit against overvoltage. The control unit outputs a voltage to the time constant setting circuit, and sets an address at a predetermined timing based on the voltage input from the time constant setting circuit when a predetermined time has passed after the output of the voltage is stopped.Type: GrantFiled: August 8, 2017Date of Patent: June 25, 2019Assignee: MINEBEA MITSUMI INC.Inventors: Kazuo Takada, Shigeki Miyaji, Yoshiaki Motoyama, Yasuyuki Hasegawa
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Publication number: 20190190417Abstract: In order to prevent erroneous detection of motor step-out even when the rotational speed of the motor crosses a resonance region of the motor under acceleration and/or deceleration, a motor control device (10) includes a control unit for performing control so as to apply a pulse voltage modulated in pulse width to each of coils of plural phases equipped in a motor (20) and periodically switch the phases of the coil currents flowing through the coils of the plural phases, a back electromotive force measuring unit (126) for providing a stop period for temporarily stopping application of the pulse voltage to a coil of any one phase out of the coils of the plural phases when the direction of a coil current flowing through the coil of the phase switches, and measuring back electromotive force induced in the coil during the stop period, and a step-out state detecting unit for detecting a step-out state when the rotational speed of the motor (20) is not in a resonance region of the motor (20) and the back electromotType: ApplicationFiled: February 21, 2019Publication date: June 20, 2019Inventors: Shigeki MIYAJI, Hidetoshi HIJIKATA, Kazuo TAKADA
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Publication number: 20190190352Abstract: To provide a motor inhibiting emission of electromagnetic noise (EMC) to the outside and a rotary apparatus including the motor. The rotary apparatus (10) of the present disclosure includes: a housing (20); a motor (40) arranged inside the housing (20); a circuit board (50) arranged inside the housing (20) and electrically connected to the motor (40); and a flexible wiring board (44) electrically connecting the motor (40) to the circuit board (50), the motor (40) including a frame (41a) formed with a conductive member, the frame (41a) electrically connected via the flexible wiring board (44) to a ground of the circuit board (50).Type: ApplicationFiled: February 22, 2019Publication date: June 20, 2019Inventors: Haruka MIYAJI, Kazuo Takada, Shigeki Miyaji, Takayuki Matsui
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Publication number: 20180294754Abstract: A control device for a stepping motor capable of suppressing a level of sound generated in association with driving of the motor is provided. The control device for a stepping motor is configured to, from when the hold period is started (t10) until the hold period ends (t12), gradually increase an absolute value of the excitation current in the A phase such that the amount of change in the excitation current per unit time is smaller than or equal to a first predetermined value. From when the hold period is started (t10) until a predetermined time elapses (t11), an absolute value of the excitation current in the B phase is gradually increased such that the amount of change in the excitation current per unit time is smaller than or equal to the first predetermined value. By the time the hold period ends (t12) after the predetermined time has elapsed (t11), the excitation current in the B phase is caused to reach zero.Type: ApplicationFiled: April 5, 2018Publication date: October 11, 2018Inventors: Koichi TAKEDA, Kazuo TAKADA, Shigeki MIYAJI, Kei YAMAZAKI
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Publication number: 20180259560Abstract: In accordance with one aspect of the present disclosure, a motor drive control device is a motor drive control device performing PWM (Pulse Width Modulation) control of a motor, wherein harmonics of a fundamental frequency for PWM control of the motor are included in noise occurring from the motor; the fundamental frequency for PWM control is larger than a frequency corresponding to a bandwidth of a predetermined radio frequency band a communication apparatus uses; and frequencies of continuous harmonic components of the fundamental frequency for PWM control appear before and after the predetermined radio frequency band.Type: ApplicationFiled: March 6, 2018Publication date: September 13, 2018Inventors: Shigeki MIYAJI, Kazuo TAKADA, Kei YAMAZAKI
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Publication number: 20180046584Abstract: An address control circuit includes a setting terminal connectable to a ground potential, a time constant setting circuit connected to the setting terminal, and a control unit connected to the time constant setting circuit and configured to set an address for serial communication. The time constant setting circuit includes a resistive element disposed between the setting terminal and the control unit and configured to protect the control unit against overvoltage. The control unit outputs a voltage to the time constant setting circuit, and sets an address at a predetermined timing based on the voltage input from the time constant setting circuit when a predetermined time has passed after the output of the voltage is stopped.Type: ApplicationFiled: August 8, 2017Publication date: February 15, 2018Inventors: Kazuo TAKADA, Shigeki MIYAJI, Yoshiaki MOTOYAMA, Yasuyuki HASEGAWA
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Publication number: 20160276974Abstract: A motor drive controller includes: a control circuit that controls an AC current flowing in a motor; a frequency modulation unit that frequency-modulates a speed of the motor when the motor is driven at a predetermined speed; and a current effective value controller that decreases an effective value of the AC current flowing in the motor as the speed of the motor modulated by the frequency modulation unit becomes closer to a resonant frequency of the motor.Type: ApplicationFiled: March 15, 2016Publication date: September 22, 2016Inventors: Shigeki MIYAJI, Takayuki MATSUI, Tetsuya SEKI
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Patent number: 8288900Abstract: A stepping motor includes a rotor assembly and a stator assembly including two stator units axially coupled to each other. The two stator units each include a pair of yokes which each include a base portion and a plurality of pole teeth extending from the base portion and which are disposed such that each of the pole teeth of one yoke and each of the pole teeth of the other yoke are arranged alternately in the circumferential direction. The pole teeth are shaped symmetric and each include a pair of slant sides inclined so as to become closer to each other with an increase of distance from the base portion, and the slant sides of adjacent pole teeth are located close to each other wherein a magnetic pole gap between the adjacent pole teeth pole teeth is about 0.2 times as large as the thickness of the pole teeth.Type: GrantFiled: July 28, 2010Date of Patent: October 16, 2012Assignee: Minebea Co., Ltd.Inventors: Takeshi Matsuno, Yoshiya Yamamura, Hiroaki Itahashi, Shigeki Miyaji, Yukihiro Terada
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Publication number: 20110043074Abstract: A stepping motor includes a rotor assembly and a stator assembly including two stator units axially coupled to each other. The two stator units each include a pair of yokes which each include a base portion and a plurality of pole teeth extending from the base portion and which are disposed such that each of the pole teeth of one yoke and each of the pole teeth of the other yoke are arranged alternately in the circumferential direction. The pole teeth are shaped symmetric and each include a pair of slant sides inclined so as to become closer to each other with an increase of distance from the base portion, and the slant sides of adjacent pole teeth are located close to each other wherein a magnetic pole gap between the adjacent pole teeth pole teeth is about 0.2 times as large as the thickness of the pole teeth.Type: ApplicationFiled: July 28, 2010Publication date: February 24, 2011Applicant: MINEBEA CO., LTD.Inventors: Takeshi MATSUNO, Yoshiya YAMAMURA, Hiroaki ITAHASHI, Shigeki MIYAJI, Yukihiro TERADA