| 摘要 |
An earth boring bit having a rotatable cutter secured to a lubricated, cantilevered bearing shaft, sealed with an improved pressure compensating rigid face seal assembly. The assembly has a rigid rigid with a radial face that opposes and engages a radial face integral with a cutter seal groove. A resilient energizer ring is compressed between opposed conical surfaces, one on the rigid ring and the other in a shaft seal groove, to force the radial faces together. The periphery of the energizer ring is inside the journal bearing surface, which is ideally aligned with the mid-section of the ring, to define an essentially constant, lubricant filled, volume between the seal assembly and the shaft seal groove - even as the cutter and seal assembly move relative to the shaft during drilling. As a result, pressure variations in the vicinity of the seal assembly are minimized. |
