| 摘要 |
<p>A drill bit and a single pass drilling apparatus are disclosed. The one-piece drill bit is rotatable about a drilling axis and has a connection portion, adapted to be rigidly connected to a drill steel, a pilot part and a reamer part. The reamer part has a leading and at least one trailing first rock machining means disposed on one side of the pilot part within a sector defined by sector angleθ. At least one of the trailing first rock machining means is axially spaced from the leading first rock machining means in the direction toward the trailing end of the drill bit.</p> |
