| 摘要 |
An axial-gap flat type motor with an annular permanent magnet and a non-magnetic disk rotor with a printed winding directly drives a coaxial tape capstan and indirectly drives the spindles engaging the supply and take-up reels in the cassette. The capstan and the spindles are shifted in a direction parallel to the motor axis in moving between an idle position and an operating position, the insertion of a cassette being sufficient to cause movement into the operating position. The capstan shaft accordingly is axially displaceable in the motor, shifting within the movable inner portion of a central bearing to which the rotor is affixed. The capstan shaft has radial projections engaging internal grooves in the movable bearing portion and springs urge these projections towards one or the other of their axial end positions in the bearing, corresponding respectively to the idle and operating positions of the capstan. Current is fed to the rotor by spring-pressed studs located in the central bearing and the annular permanent magnet stator. Light passing through slots in the edge of the rotor disk is optoelectrically detected to produce a speed regulating signal to a regulating circuit that controls the voltage of which current is supplied to the motor. The low moment of inertia of the drive makes the speed regulation accurate and facilitates transitions into and out of fast-forward and fast-rewind modes. The printed windings on the rotor produce smooth motion in response to direct current excitation.
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