| 摘要 |
<p>An earth boring bit having a lubrication system that includes a pressure compensator and seals to confine lubricant within the bearings between rotatable cutters and shafts, the seals being of the asymmetrical shear/compression type, each half of which having a load deflection curve resulting from components satisfying the following criteria: DH > ApS and DC > ApS ¢(S-1)/S!1/2 Where: DH = Assembly deflection of shaft seal ring with bearing thrust faces in contact (in.); DC = Assembly deflection of cutter seal ring with bearing thrust faces in contact (in.); Ap = Axial cutter play (in.); S = Ratio seal to cutter movement. Also preferably DC ? DH¢(S-1)/S!1/2</p> |
