| 摘要 |
PROBLEM TO BE SOLVED: To provide a high precision encoder device capable of preventing adhesion of mistily oily material generated in high temperature onto photodetectors and rotational sign plates. SOLUTION: In an encoder device provided with a light source 8 and a light receiver 6 face to face so as to pinch the rotational sign plate 4 attached to a rotational axis 3, a bearing 2 wherein a rotational shaft 3 is inserted, and a circular disk 5 of thin plate fixed to the rotational shaft 3 are provided. In the gap between the disk 5 and the bearing 2, a volatile material 9 is sealed so that the oily material leaking from the bearing 2 is sealed in the constitution. By this, when the encoder device rotates under high temperature in high speed, mistily oily material tends to leak out of the seal gap of the bearing 2; however the oily material seals the volatile material 9 in the gap between the disk 5 and the bearing and so it never leaks out, and adheres to the photodetectors (light receiver 6, light source 8) and the rotational sign plate 4. Thus, precision of the encoder signal can be assured. COPYRIGHT: (C)2006,JPO&NCIPI
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