| 摘要 |
PURPOSE:To eliminate the adverse influence of leak magnetic fluxes on the recording and reproducing performance of a head by mounting a magnet for generating an index signal on the back surface of a rotor and disposing a sensor near this magnet. CONSTITUTION:A friction plate 74 is fixed to the rotor 73 and a piezoelectric driving body 75 is disposed on a base 1, by which an ultrasonic motor is constituted. The magnet 101 for generating the index signal is mounted on the back surface of the rotor 73 and a sensor 102 consisting of a Hall element, etc., is disposed to face the magnet 101. The sensor 102 is mounted to a PCB adjustable in a circumferential direction by means of a screw, etc., to the base 1. This magnet 101 for generating the index signal is disposed in the position parted at a sufficient spacing from heads 14, 15 and, therefore, the influence of the leak magnetic fluxes is not applied on the heads 14, 15. |
