| 摘要 |
PROBLEM TO BE SOLVED: To hold the detection of the information of a large amount of rotation without requiring battery backup even in the case that a main power source is turned off. SOLUTION: A rotary absolute encoder is provided with an absolute position detector for detecting an absolute position within one rotation of a disk scale provided on a rotary shaft 3. A rotating body 9 provided with a pawl part 21 rotated by the rotary shaft is provided, and a plate spring 27 positioned on the circumference of the rotating body 9 and which can be repulsed by the pawl part on the track of the rotation of the pawl 21 is provided. The plate spring 27 is repulsed by the pawl part 21 to accumulate repulsive force, and when it is out of the pawl part, the plate spring 27 is repulsed. The moving energy of the plate spring 27 is converted into electric energy by a piezoelectric element 35 being a power generation device 31. The large amount of the rotation is counted by using the electric energy in a counter circuit, and even in the case that the main power source is turned off, the large amount of the rotation is counted to hold the detection of the information since a counting amount is stored.
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