| 摘要 |
PROBLEM TO BE SOLVED: To provide a bearing device in a spindle device or the like adapted to be used in a machine tool, which rotatably journal a rotary shaft so as to allow the same to axially move while the shaft is rotated at a high speed. SOLUTION: A plurality of rolling balls 10 which are formed in a spherical shape, are located between an inner and an outer race 11, 12, and are rotatably held at predetermined intervals in a circumferential direction by means of a cage 13, the balls 10 rolling on tracks 11a, 12a of the inner and outer race 11, 12. Of these tracks 11a, 12a the track 11a of the inner race 11 has a rectilinear track configuration having a linear cross-sectional shape, and accordingly, a rotary shaft 1 is rotatably journalled, being axially movable. Further, it is possible to prevent occurrence of frictional heat caused by rolling of the balls and to ensure a high lubricity by lubrication oil, thereby it is possible to cope with high-speed operation of a spindle device.
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