| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide a bit device enabling the reduction of the abrasion of a bearing mechanism to the utmost and consequent prolongation of the life. SOLUTION: A cutter member 3 having a cutting edge is supported axially and rotatably in relation to a shaft 2 and a bearing mechanism 5 is interposed between the cutter member 3 and the shaft 2. The bearing mechanism 5 is equipped at least with a radial bearing 6 that bears a load in the radial direction and a thrust bearing 7 that bears a load in the axial direction, and the radial bearing 6 is composed of a shaft-side divided bearing member 6A and a cutter-part-side divided bearing member 6B. The bearing members 6A and 6B are butted or brought into sliding contact with each other so that they can rotate relatively to each other.</p> |
