| 摘要 |
PROBLEM TO BE SOLVED: To prevent mist of oily matter generated under a high temperature and dust from depositing on a light receiving and emitting element or a rotary code plate, when an encoder is rotated at a high speed, so as to provide a precise encoder unit. SOLUTION: The encoder unit is constituted of: the rotary code plate 4 attached to a rotary shaft 3; substrates 7, 9 arranged in opposed positions with the rotary code plate 4 therebetween, and including a light source and a photoreception body in each thereof; and a bearing 2 inserted penetratedly with the rotary shaft 3, and is provided with: a protection plate 5 rotated together with the rotary code plate 4 in a clearance between the rotary code plate 4 and the bearing 2; and an adsorption substance 10 arranged along a circumferential direction of the protection plate 5 to adsorb the oily substance and the dust generated from the bearing when rotated, and contaminants are restrained by the protection plate 5 and the adsorption substance 10 from being deposited onto the protection plate 5. COPYRIGHT: (C)2007,JPO&INPIT
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