Composite grease for rock bit bearings
AssigneeSmith International, Inc.
InventorAlan L. Newcomb
Life of this patent
Estimating the term…
Abstract
A rock bit for drilling subterranean formations is lubricated with a grease composition comprising molybdenum disulfide particles in the range of from 6 to 14% by weight, copper particles in the range of from 3 to 9% by weight, a metal soap thickener in the range of from 4 to 10% by weight, and a balance of primarily hydrocarbon oil.
Claims40
A grease composition for lubricating a rock bit for drilling subterranean formations comprising:
- copper particles in the range of from 3 to 9% by weight;
- molybdenum disulfide particles in the range of from 6 to 14% by weight;
- a metal soap wherein the metal is selected from the group consisting of aluminum, barium, calcium, lithium, sodium and strontium, and mixtures thereof;
- and
- a balance of primarily hydrocarbon oil.
A rock bit for drilling subterranean formations comprising a bit body including a plurality of journal pins each having a bearing surface;
- a cutter cone mounted on each journal pin and including a bearing surface;
- a pressure compensated grease reservoir in communication with such bearing surfaces;
- and
- a grease in the grease reservoir and adjacent the bearing surfaces comprising:
- copper particles in the range of from 3 to 9% by weight;
- molybdenum disulfide particles in the range of from 6 to 14% by weight;
- a metal soap wherein the metal is selected from the group consisting of aluminum, barium, calcium, lithium, sodium, and strontium, and mixtures thereof;
- and
- a balance of primarily hydrocarbon oil.
A method for lubricating a rock bit for drilling subterranean formations, the rock bit including a bit body and a plurality of cutter cones mounted on the bit body with journal bearings, comprising the steps of:
- evacuating a portion of the rock bit body including the journal bearings;
- and
- introducing grease into the evacuated portion of the rock bit body and journal bearings, said grease comprising:
- copper particles in the range of from 3 to 9% by weight;
- molybdenum disulfide particles in the range of from 6 to 14% by weight;
- a metal soap wherein the metal is selected from the group consisting of aluminum, barium, calcium, lithium, sodium and strontium, and mixtures thereof;
- and
- a balance of primarily hydrocarbon oil.
A grease composition for lubricating a rock bit comprising about 11% by weight molybdenum disulfide particles, about 5% by weight copper particles, about 2% by weight aluminum complex soap, about 4 to 5% by weight lithium soap, about 2% by weight silica powder and a balance of primarily hydrocarbon oil.
Dependencies are inferred from the claim text.