| 摘要 |
Lubricant is circulated from a lubricant reservoir to the bearings of a rotary rock bit and back to the lubricant reservoir by a lubricant circulation system that is operated by rotation of the cone cutter upon the bearing pin of the bit. A spiral groove system in the inner surface of the cone cutter operates as a viscous or ram pump when the cone cutter is rotating against the corresponding bearing surface of the bearing pin and provides the pumping action for circulating the lubricant. A seal is positioned between the rolling cone cutter and the arm of the bit to maintain lubricant in the bearing area and to prevent fluid in the borehole from entering the bearing area. A lubricant reservoir is located in the bit body. A first passage connects the lubricant reservoir with the bearing area to channel lubricant from the lubricant reservoir to the bearing area. A second passage extends from the bearing area to the lubricant reservoir to allow lubricant to be channeled back to the lubricant reservoir. A spiral groove system in the bearing surface of the cone cutter operates as a viscous or ram pump when rotating against the corresponding bearing surface of the bearing pin providing a pumping action to circulate lubricant from the lubricant reservoir through said first passage to the bearing area and from the bearing area through said second passage back to the lubricant reservoir.
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