| 摘要 |
PURPOSE:To secure necessary accuracy without grinding process after assembly by using a part of the outer ring of a bearing whose inner ring is press-fit in the spindle as the centering part at chucking a magnetic disc. CONSTITUTION:The bearing 14 is press-fit in the lower part of the spindle 12, and the bearing 31 is in the upper part. The said spindle, coils 17a and 17b, and magnets 16a and 16b constitute together a roter 15A of a flat opposing- type brushless motor. The upperpart 15E of the said rotor 15A extends to approximate center of the outer ring 31a of the bearing 31, and serves as the chucking centering part 31c. The part 31c, the inner walls 6b and 6c of the magnetic disc 2, and a spring 7 directly abuts on each other. The bearing 31 originaly is manufactured with excellent accuracy, therefore, the error when the disc 2 is chucked and turned is limited <= several mum.
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