| 摘要 |
<p>Chips are segmentalized to have a desired width and the chip controllability is improved and the tool rigidity is improved. A drilling tool (1) is provided that includes: a tool body (2) having an outer shape having a substantially cylindrical shape rotated around an axis line —‹; a chip discharge groove (4) formed at the outer periphery of the tool body (2) to extend from the tip end side of the tool body (2) toward the rear end side; at least one sub-groove (7) formed at an inner face (6) facing the front side in the tool rotation direction T of the chip discharge groove (4) to extend from the tip end side of the tool body (2) toward the rear end side; a rake face (10); a tip end flank face (16); and a cutting edge (14) formed at a ridge line at which the tip end flank face (16) intersects with the rake face (10). The plurality of rake faces (10) form a step-like shape having at least one step section (11). The drilling tool (1) is configured so that the turnup section (8) at the rear end side of the sub-groove (7) is turned up in a different direction from the direction along which the turnup section (5) of the rear end side of the chip discharge groove (4) is turned up.</p> |
