| 摘要 |
<p>A drill bit having a body with a shaft thereon, a roller cutter, an annular thrust bearing, means for connecting said roller cutter to the thrust bearing, means for retaining said thrust bearing on the shaft, and a lubrication system containing the thrust bearing and the retaining means with the lubrication system seal positioned between the outer edge of the roller cutter and the base of the shaft.</p> |
