| 摘要 |
A well drilling bit comprises a bit body with a centralized portion and a plurality of radially and circumferentially spaced legs depending longitudinally therefrom. A respective cutter body is rotatably mounted on the free end of each leg with bearing means. The bit body has a respective lubricant passage communicating with each bearing and a respective upwardly opening lubricant reservoir recess, the recess also communicating with a respective vent port opening downwardly through the bit body. A respective lubricating mechanism is disclosed in each lubricant reservoir recess, and each such mechanism comprises an elastomeric pressure compensating diaphragm extending across the recess and sealed with respect thereto, dividing the recess into a lower portion communicating with the vent port and an upper portion communicating with the lubricant passage. The mechanism also comprises an integral diaphragm protector located generally above the diaphragm in the upper portion of the lubricant reservoir recess, having a primary, downwardly opening cavity for receipt of lubricant and aligned to receive the diaphragm when the diaphragm is contracted. The protector has a flow path communicating the interior of the primary cavity with the upper portion of the reservoir recess externally of the protector. The protector also has a cap portion sealed with respect to the lubricant reservoir recess above the point of communication between the flow path and the lubricant passage and connected to the bit body by a connector so as to retain the diaphragm in the lubricant reservoir recess.
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