Kabushiki Kaisha Sankyo Seiki Seisakusho

Omron Tateisi Electronics Co.

Jinichi Ito

Kiyoshi Miyazaki

Hayato Naito

Kenji Sawai

Hiroo Ashibe

Tuneto Takeuchi

Tsuneto Takeuchi

In a servo motor system, consisting of a servo motor unit, a servo driver unit, power transmission lines for supplying electric power from the servo driver unit to the servo motor unit, and signal transmission lines for supplying electric signals from the servo motor unit to the servo driver unit, to the end of reducing the number of the signal transmission lines without requiring any particularly high-speed or high-quality signal transmission lines, the servo motor unit comprises a parallel-serial signal conversion circuit for converting outputs from a pole sensor, a rotary encoder, and an abnormal condition sensor into a single serial signal which is transmitted to the servo driver unit via one of the signal transmission lines. The servo driver unit comprise a serial-parallel signal conversion circuit for separating from the serial signal the aforementioned outputs from the various sensors. By suitable logical combination of the parallel signals, the number of bits required for the transmission of the serial signal can be reduced.

Servo motor system requiring a reduced number of signal transmission

A drive circuit for a three-phase brushless motor in which two Hall detectors are spaced 120.degree. apart in electrical angle near the rotors to detect magnetic flux signals for two phases. Their outputs are summed and inverted to form the third phase signal. The three phase signals drive the respective coils on the stator. The three phase signals are also separately squared and then added to adjust, in a feedback fashion, the current through the Hall detectors, whereby torque ripple is reduced.

Reduced ripple drive circuit for a brushless motor

A commutatorless DC motor drive device in which errors due to offset voltages of differential amplifiers used therein are eliminated to thereby cause the rotor to rotate at a stable speed. Double-balance differential amplifier circuits are arranged to receive outputs of corresponding magnetic sensitive elements, such as HALL elements, upon differential input terminals thereof and external control signals upon differential control voltage terminals thereof. The outputs from the magnetic sensitive elements are amplified with an amplification factor determined by the control signals. The control signals have an amplitude determined in accordance with the rotational speed of the rotor. Output circuits control the amount of current fed to the stator coils in accordance with differential outputs of the double-balance differential amplifier circuits.

Commutatorless DC motor drive device

A motor speed control device for a small DC motor in which the speed of rotation of the motor is maintained stable during ambient temperature changes and changes in the load applied to the motor. A temperature compensation resistor is coupled in series with a voltage divider circuit and the combination thereof coupled across the motor. A motor control circuit is provided having first through fourth control terminals. The first control terminal is coupled to the junction between the temperature compensation resistor and the voltage divider circuit, the second control terminal to the voltage division point, the third control terminal to the junction between the voltage divider circuit and the motor, and the fourth control terminal is coupled to ground. The motor control circuit includes an error detecting circuit having inputs coupled to the first and second control terminals with a voltage reference source coupled in series with the first input terminal to the error detecting circuit. The output of the error detecting circuit drives both shunt transistors coupled between the first and fourth control terminals and a drive transistor means coupled between the first and fourth control terminals.

Growing community of inventors

Ina, Japan

Jinichi Ito