| 摘要 |
<p>PURPOSE:To reduce a ripple of torque of a driving source and also to turn a reel turntable properly by a simple constitution by composing a rotation transmission mechanism for the reel turntable of a magnet and a body of revolution generating an eddy current loss. CONSTITUTION:To output shaft 4 of motor 3 provided on the bisector between supply reel turntable 1 and take-up reel turntable 2, pulley 6 with integrally-provided permanent magnet 5 is fixed and wheel 7 with fixed disk 8 of aluminium, etc., generating an eddy current loss and back yoke 9 of a ferromagnetic body such as iron is fitted rotatably. As a result, as a supply voltage across motor 3 is rised, motor 3 starts rotating and after torque is generated at reel turntables 1 and 2 through the magnetic adsorption of back yoke 9 and magnet 5, an eddy current proportional to a difference in rotational frequency between motor 3 and wheel 7 is generated through disk 8 to generate torque in a direction where the rotation of motor 3 is stopped. Therefore, reel turntable torque in recording and reproducing modes and that in rewind and fast forward modes can automatically be obtained according to variation in rotational frequency of motor 3.</p> |
