| 摘要 |
<p>PURPOSE:To make it possible to obtain large reel turntable torque with variations in rotational frequency of a driving source by composing a rotation transmission mechanism of a magnet and a body of revolution generating an eddy current loss and by specifying the number of poles of the magnet. CONSTITUTION:As a difference in rotational frequency between motors 3 and wheel 7 is gradually increased by increasing a voltage supplied to the motor 3, an eddy current is generated depending upon a difference in rotational frequency between disk 8 and magnet 5 and the torque of this eddy current increases in proportion to the difference in rotational frequency. In fast traversing or rewinding mode, a high voltage is applied to motor 3 to increase the rotational frequency. In reproduction, on the other hand, the voltage applied to motor 3 is decreased. At this time, although motor 3 has cogging, a transmission mechanism by the eddy current nearly eliminates a ripple of torque generated by motor 3. In this device, although magnet 5 gives effect to magnetization with 4-10 poles, the largest torque can be extracted and a circular disk can lower the rotational frequency of motor 3 to suppress dispersion in torque.</p> |
