| 摘要 |
PURPOSE: To achieve gripping required between a bearing and a shaft by fastening a tapered sleeve so as to enlarge the diameter of a first shaft in order to carry out interference fitting and coupling between a second and the first shaft so as to facilitate the mounting and removable of the bearing and inhibit relative motion between the shaft and the inner ring in order to apply pre-load to the bearing. CONSTITUTION: A rotary shaft 20 as a second shaft for rotating a drill head is inserted in a shaft head 10, and is attached by a tapered sleeve 25 while a bearing unit and the tapered sleeve 23 are fastened to the tapered surface 22 of the rotary shaft 20. With thus fastening, the shaft head 10 and inner races 16, 17 are firmly gripped, and accordingly, a fastening degree of the shaft at a tapered seat surface and a loose fit value between the inner races and the shaft head before the fastening are set so that the gripping between the inner races 16, 17 and the shaft head 10 exhibits interference fit after completion of the fastening. Further, the rotary shaft 20 and the tapered sleeve 23 serving as a diameter enlarging member can apply a predetermined prepressure to the bearings 11, 12, that is, loose fit is initially given so as to make is possible to facilitate the mounting and removal and as well to exhibit interference fit after completion of the fastening, thereby it is possible to exert the pre-load. |
