| 摘要 |
<p>The present invention is directed to a rotary shaft seal assembly (41) and, more particularly, to an assembly including a continuous, annular, but axially variable seal (52, 66) for providing hydrodynamic lubrication between the seal (52, 66) and the rotating shaft (14). The seal assembly (41) uses differential pressures to maintain the seal (52, 66) compressed as it wears. The present system is particularly useful in drilling motors utilizing the movement of drilling fluid under pressure to operate the motor parts and thereby to drive a drill bit. Annular seal mounting members (59, 46) are positioned above and below the seal (52, 66) and have surfaces (64, 53) to matingly engage the seals (52, 66). The mounting members (59, 46) are permitted to move relative to one another in response to a pressure differential developed across the motor to compress the seals (52, 66) therebetween to accommodate wear. An oil chamber (28) above the upper mounting element (59) communicates drilling fluid pressure inside the drill pipe to the upper mounting element (59). The pressure of the annular space below the motor housing is communicated to the lower mounting element (46) by means of a lower chamber (51). The seals (52, 66) are protected from the abrasive drilling fluids by the fluids in the chamber (51) and seals (47).</p> |
