| 摘要 |
PURPOSE:To improve the controllability of a motor reduced in its cost of manufacture by providing a pressure detecting part, which detects a pressure with a stator, in an annular rotor and detecting a phase difference between a signal, output from the pressure detecting part, and a signal supplied to the annular resonator and obtained from a motor driving circuit. CONSTITUTION:A pressure detector 1-120 built in a rotor is constituted of a piezoelectric element and a piezoelectric material of PVDF or the like, and a pressure detecting part 1-125 is provided in one part of the detector. A signal 1-a from this detector is converted by a waveform processing circuit 1-4 into a rectangular pulse signal 1-b synchronized with the signal 1-a. And the signal 1-b is fed to an incremental rotary angle signal generator circuit 1-3, together with a signal 1-c obtained from a motor driving circuit 1-2. In the incremental rotary angle signal generator circuit 1-3, a phase difference between two vibrative signals of the signal 1-c and the signal 1-b relates to a rotary angle of the rotor. When this phase difference exceeds a specified quantity, an incremental pulse is output. |
