| 摘要 |
PURPOSE:To detect abnormal vibration or the like transmitted to a surface of a conducting member accurately, by arranging a magnetic field former noncontact along the surface thereof to check an eddy current generated at a part where a magnetic field to be positioned in a surface layer part. CONSTITUTION:A sensor 20 is arranged noncontact with a gap slightly separated from an outer surface 22 of a shaft 12. The sensor 20 is made up of an electromagnet 26 arranged in a case 24 and a detection coil 30 provided at an opening 28. Then, DC is supplied to an excitation coil 34 to form a radial magnetic field between the other end of a core 32 and the opening 28. Then, as the shaft 12 vibrates at the right angle to the outer surface 22 thereof, an eddy current develops in a surface layer part corresponding to a vibration and an induction current flows through the coil 30 to cancel changes in a magnetic field formed by the eddy current and is converted into an electrical signal to fetch. Then, noncontact detection of vibration enables highly accurate detection of abnormal vibration.
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