Minebea Mitsumi Inc.

Minebea Company, Limited

Shigeki Miyaji

Kazuo Takada

Takayuki Matsui

Kei Yamazaki

Haruka Miyaji

Tetsuya Seki

Hidetoshi Hijikata

Ayaka Shimada

Yukihiro Terada

Koichi Takeda

Yasuyuki Hasegawa

Takeshi Matsuno

Yoshiaki Motoyama

Yoshiya Yamamura

Hiroaki Itahashi

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.

Motor and rotary apparatus including the same

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 ().

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.

Motor drive control device, motor unit, and motor drive control method

In order to suppress high-frequency noise in micro-step driving of a stepping motor, a motor control device () includes an H bridge circuit () and control means for driving a switching element of the H bridge circuit () 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&#xb0;, the control means switches the H bridge circuit () every PWM cycle to the charge mode and then to the slow attenuation mode. In a range exceeding +52&#xb0; and to +90 degrees where the reference current value starts ascending, the control means switches the H bridge circuit () 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.

Motor current control device and motor current control method

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 () 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 () and periodically switch the phases of the coil currents flowing through the coils of the plural phases, a back electromotive force measuring unit () 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 () is not in a resonance region of the motor () and the back electromotive force measured by the back electromotive force measuring unit () satisfies a predetermined step-out state determination criterion.

Motor control device and step-out state detection method

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.

Control device for stepping motor and control method for stepping motor

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.

Motor drive controller and method for controlling motor

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.

Motor drive control device and method for determining controlled frequency for motor

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.

Address control circuit capable of setting address rapidly and method of setting address after power-on reset, the address control circuit providing protection against over-voltage

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.

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Hamamatsu, Japan

Shigeki Miyaji