| 摘要 |
PURPOSE:To materialize microminiature equipment by attaching a capacity type of encoder for detection of the rotational angle of a rotor to the periphery of the rotor, and sharing a drive source for an ultrasonic motor and the encoder. CONSTITUTION:An electrode 33 is made as a circular pattern around a rotor 11, on the surface of a printed board 20. A rotary disc 32 is attached to the periphery of the rotor 11 so as to be opposed slit space part to the electrode 33 made as a pattern, and besides it is arranged so as to rotate with the rotor 11. The square wave voltage obtained by a frequency divider is given to the electrode 33 constituting an encoder 30, whereby the electrode 33 generates a rotating electric field. A motor is driven by this, and the rotary disc 32 is rotates together with the rotation of the rotor 11. When the rotary disc 32 rotates, the phase of the rotating electric field generated by the electrode 33 changes within the range of 0-360 deg., according to its rotational angle, whereby the rotational angle of the rotor is detected. |
