| 摘要 |
The present invention provides a mechanical seal for rotary rock bits with a uniquely formed hydrodynamic wave geometry on the sealing faces. The faces are f irst manufactured flat and smooth, then upon assembly are elastically deformed into a hydrodynamic geometry by the energizing system. One or both of the mechanical sealing faces are lapped flat to less than about six helium light bands and poli shed to a minimum of about 5 micro-inch RA surface finish across the entire width of the s ealing faces. After the smooth flat sealing surface is formed, the mechanical seal face elastically deforms into a hydrodynamic wave geometry. The typical deformation has a magnit ude greater than about three helium light bands more than the original surface. The deformed surface maintains its finish of less than about five micro-inches RA. T he region of the sealing surface at the outer periphery of the seal does not have a wave geometry. Rather the portion of the seal face at the periphery is flat and paral lel to its mating seal ring to exclude abrasives and eliminate lubricant leakage.
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