| 摘要 |
PURPOSE:To facilitate the work for positioning of an original point and miniaturize a device and realize the cost reduction, by detecting the position of the original point of a mover, with a light-projecting element, a light-receiving element arranged on a stator and a light shielding plate set on a mover. CONSTITUTION:On the upper surface of a back yoke 11 positioned between front and rear permanent magnets 12b, 12b on a stator 1, light-projecting and light-receiving element units 3 are arranged, and on the lower surface of a mover 2, a light shielding plate 4 for operating them is set. The units 3 are constituted with a pair of the light-projecting element and the light-receiving element confronting the direction orthogonal to the advancing direction of the mover 2, confronting a housing set adequately between the permanent magnets 12b, 12b. When the mover 2 is positioned at the end section of a stroke, then the light shielding plate 4 is positioned between the light-projecting element and the light-receiving element, and projected light is interrupted. The end of the stroke of the mover 2, namely, the original point is detected by the output of the light-receiving element.
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