VIBRATION DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To make a vibration detecting device lightweight and compact by inserting a magnetic substance or a nonmagnetic substance in a fixed solenoid to make it move freely, and catching the change of generated inductance to detect vibration. SOLUTION: A ferrite core 2 is embedded in an insulator cylinder 5. An elliptic cavity 3 is provided in the facing position of the ferrite core 2, and a ferrite ball 4 is inserted therein. A coil is applied in such a way as to cover the center parts of the ferrite core 2 and elliptic cavity 3 to form a solenoid 1. A vibration detector 6 is connected to an oscillating circuit 7 and further to a frequency discriminating circuit 8. The ferrite ball 4 inserted in the elliptic cavity 3 moves in the elliptic cavity by external vibration so as to generate the change of inductance of the solenoid 1 and to fluctuate oscillation frequency in the oscillating circuit 7. The frequency discriminating circuit 8 catches frequency variation from the fluctuation of oscillation frequency and outputs it as vibration detection output. The vibration of the ferrite ball 4 can thereby be detected.