| 摘要 |
<p>The invention concerns a self-penetrating drilling method and a thrust-generating tool: the tool (1) comprises N blades (2a, 2b, 2c, 2d). Each blade comprises K drill bits (3a, 3b, 3c, 3d). The shapes, positions and orientations of said drill bits are determined in the following manner: the kth drill bit of the last blade drills, at the (q-1)th of the tool rotational cycle, a cut in the rock downstream of the one produced by the (k+1)th drill bit of the first blade at the qth rotational cycle of the tool; the kth drill bit of the nth blade drills, at the qth rotational cycle of the tool, a cut in the rock downstream of the one produced by the kth drill bit of the (n+1)th blade at the qth rotational cycle of the tool; the normal to the leading edge of the drill bit has a component along the axis of rotation oriented towards upstream.</p> |
