ROTATION DETECTING DEVICE

摘要

PROBLEM TO BE SOLVED: To enable rotation of a rotary body rotatable relative to a fixed body with a simple structure, and to miniaturize and reduce cost. SOLUTION: This device 10 is a rotation detecting device for detecting rotation of a rotary body 12 rotatable relative to a fixed body 11. In this case, the rotary body 12 has an irregular part 31 formed along the direction of rotation of the rotary body 12, for giving a change to the air flow at the time of rotation of the rotary body 12. A sensor 30 for detecting rotation of the rotary body 12 is a sensor for detecting a change of the air flow generated by the irregular part 31 at the time of rotation of the rotary body 12.