| 摘要 |
PROBLEM TO BE SOLVED: To provide an excavation tool which can increase the longevity by preventing fall, a loss and wear of a chip, and which can increase the drilling speed. SOLUTION: An excavation part 13 is formed at the tip of a tool body 11, and a plurality of chips 20 are provided to the excavation part 13. The outer diameter D of the excavation part 13 of the excavation tool is made 95 mm long or less. Then a face part 14 and a gauge part 15 are provided to the excavation part 13. The face part 14 is directed toward the tip side of the tool body 11, and the gauge part 15 arranged at the outer peripheral end of the face part 14 intersects the face part 14 so that the gauge part 15 is inclined. Then the gauge chip 21 provided to the gauge part 15 is arranged so that it is directed toward the direction in which the gauge chip 21 intersects an axis O at an angle ofθ. The ratio between the diameter d1 of the gauge chip 21 and the diameter d2 of the outer peripheral chip 22 is set within the confines of 0.83≤d2/d1≤1.0, and the ratio between the number n1 of the gauge chip 21 and the number n2 of the outer peripheral chip 22 is set within the confines of 0.375≤n2/n1≤0.667. COPYRIGHT: (C)2008,JPO&INPIT
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