| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a drill bit in which the shape of a brazing filler metal being adhered is improved, the chip generated in drilling is minimized, and drilling life is extended. <P>SOLUTION: The drill bit 1 uses the brazing filler metal 4 on tip of a columnar or cylindrical body 2 to deposit diamond abrasive grain 5. On partial or whole apical surface of the body 2, a hollow section 17 receding axially-backward to the apical surface was formed. This hollow section 17 is axisymmetrically-formed so that its deepest part 17a may match rotational center of the drill bit 1. Further a hollow section 16, wherein diameter of the body 2 is tapered, was formed on a part of side face on the body 2. The brazing filler metal 4 is applied so as to entirely cover these hollow sections 16 and 17. <P>COPYRIGHT: (C)2012,JPO&INPIT |
