| 摘要 |
<p>An earth boring bit having a pressure compensating seal assembly which includes a resilient packing ring, a rigid backup ring and a wave spring to permit axial displacement of the resilient ring in an elongated seal groove while resisting destructive distortions of the resilient ring. The lubrication system has a lubricant volume correlated with the volume of the passages and spaces and the maximum seal displacement. A measured amount of lubricant is withdrawn from the system during assembly for subsequent compression as the bit is lowered into a liquid-filled bore hole to position the seal assembly intermediate the end walls of the seal groove.</p> |
