| 摘要 |
An optical rotary encoder using a fluid bearing, which is space-saving, holds down the costs for high-precision processing of components, and has excellent maintainability. A rotary disk is fixed to a disk holder and accommodated in a cylindrical case together with a fluid bearing mechanism and an optical detection unit. The optical detection unit and the fluid bearing mechanism compose a static system with the case, which maintains a stationary state even if a rotary shaft is rotated, and are mounted on static system mounting portions with the case. The disk holder and the rotary disk are fitted on the rotary shaft. Compressed air is sprayed onto both sides of the rotary disk through a compressed air flow path and a compressed air nozzle, to thereby restrict the displacement of the disk, which is generated in the direction parallel to the rotary shaft. The compressed air is also sprayed through the compressed air flow path onto the outer circumference of the disk holder, to thereby restrict the displacement of the disk, which is generated in the direction perpendicular to the rotary shaft. It is possible to use helium or oil as fluid to be used.
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