| 摘要 |
PURPOSE:To measure an angle and a rotation quantity with a high precision, by arranging a detecting part on the supporting material, which is provided on the outside circumferential face of a disc material, and by keeping relative positions of the detecting part and the main scale of the pulse disc constant. CONSTITUTION:When a pulse disc 1 and a hub 12 which have eccentricity for the axis of a rotating shaft 13 are rotated, the outside circumferential face of the hub 12 is slided by 2epsilon in one rotation for an eccentricity quantity epsilon. At this time, a sliding body 19 is brought into contact with the hub 12 at points 20a and 20b by a fixed base 15 and is slided similary to the motion of the center of the disc 1. This sliding is transferred to a detecting part 2A through a flat spring 22, and a main scale 1a and an index scale 4 hold predetermined positional relations accurately. Consequently, the error of the detection signal from a photodetector 10 is cancelled completely approximately. |
