Patent ID: 7495750

Claim:
A monitoring device for a rotating body, the rotating body rotatably provided apart from a fixed body, comprising: a light source for emitting light; a rotation-side optical fiber attached to a deformation-measuring part of the rotating body and being extended toward one end of the rotating body so that one end of the rotation-side optical fiber is placed on a rotational axis of the rotating body; at least one deformation sensor made by forming a plurality of Bragg gratings in a portion of the rotation-side optical fiber along its lengthwise direction, the portion of the rotation-side optical fiber being attached to the deformation-measuring part of the rotating body; a reference sensor made by forming a plurality of Bragg gratings in the rotation-side optical fiber along its lengthwise direction adjacent to the one end of the rotation-side optical fiber placed at the one end of the rotating body; a fixed-side optical fiber connected to the light source and being mounted to the fixed body so as to be opposed to the one end of the rotation-side optical fiber; and a signal processing unit connected to the fixed-side optical fiber, the signal processing unit receiving the light reflected from the deformation sensor and the reference sensor, the signal processing unit detecting a deformation of the rotating body by subtracting a signal corresponding to the light reflected from the reference sensor from a signal corresponding to the light reflected from the deformation sensor.