| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide a drilling bit that allows efficient arrangement of house-shaped chips made of cemented carbide to allow an efficient decrease in amount of cemented carbide to be used while maintaining drilling performance. <P>SOLUTION: A drilling bit is provided in which five house-shaped chips 2a to 2e made of cemented carbide are radially arranged on a chip mounting surface 12 of a metal base 1. While displacing the position by rotation at which the five house-shaped chips 2a to 2e of cemented carbide hit, an impact is given by vibration in a forward-backward direction to a subject to be drilled, thereby performing drilling. Among the five house-shaped chips 2a to 2e of cemented carbide, short chips 2b and 2e of cemented carbide are shorter in a longitudinal direction than long chips 2a, 2c and 2d of cemented carbide. The five house-shaped chips 2a to 2e of cemented carbide have their respective outer ends 2a1 to 2e1 that are arranged along the outer peripheral side of the chip mounting surface 12 at which a drilling load (a drilling amount) is relatively high. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
