| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a rotor rotation detection device which achieves weight saving of a rotor arranged in liquid and can detect the rotation of the rotor.SOLUTION: This invention is applied to a rotor 3 having a rotary wing 30 which rotates in liquid in a chamber formed in a housing 2. A rotor rotation detection device includes an origination side piezoelectric element 40 and a reception side piezoelectric element 50 which are arranged at positions outside the chamber and for detecting the rotation of the rotary wing 30 of the rotor 3, and a signal processing section 6 which generates the rotation detection signal from the detection signal of the reception side piezoelectric element 50. With this configuration, the ultrasonic wave originated from the origination side piezoelectric element 4 attenuates with transmission through the rotary wing 30 of the rotor 3 or reflection on the rotary wing 30, presence/absence of the rotation of the rotor 3 is determined by detecting the attenuation by the reception side piezoelectric element 50, the rotation of the rotator 3 is detected based on the determination, and a rotation detection signal k can be generated.</p> |
