Rock bit bearing structure
AssigneeSmith International, Inc.
InventorArthur A. Villaloboz
Life of this patent
Estimating the term…
Abstract
A rock bit has a rotary cutter cone journaled on a fixed journal bearing shaft with the radial load being taken by a cylindrical journal bearing. The friction bearing portion of the fixed shaft has a groove extending around the periphery of the shaft. The groove is filled with a bearing metal over an arc on the lower load bearing fraction of the shaft. The remaining unfilled portion of the groove is connected through a lubricant supply passage in the bit body with a pressure-compensated grease reservoir in the bit body, to supply lubrication to the journal bearing.
Claims26
A rock bit comprising a drill bit body having a journal bearing spindle shaft, a rotary cutter cone rotatably supported on the shaft, the shaft having a cylindrical bearing portion, the cutter cone having a cylindrical bore extending around the bearing portion for forming a friction bearing, the bearing portion of the shaft having a shallow groove extending around the periphery thereof, bearing metal applied in the groove over less than about half the circumference of the groove, the bearing metal forming a surface flush with said cylindrical bearing portion, a pressure compensating grease reservoir in the bit body, and a passage connecting the grease reservoir to the groove.
A rock bit comprising:
- a bit body;
- a journal bearing shaft on the bit body;
- a rotary cutter cone rotatably supported on the journal bearing shaft and including a cylindrical bore extending around a portion of the journal bearing shaft for forming a friction bearing surface;
- a cyclindrical bearing portion on the journal bearing shaft opposite the cylindrical bore, said cylindrical bearing portion including a pair of axially spaced apart cyclindrical bearing surfaces of hardened steel, a circumferential groove between the cylindrical bearing surfaces, and a bearing metal applied in the groove in only the lower load bearing fraction of the journal bearing shaft and flush with the cylindrical bearing surfaces;
- a lubricant reservoir in the bit body;
- means in the lubricant reservoir for compensating for pressure changes;
- and
- a lubricant passage between the reservoir and the unfilled portion of the circumferential groove.
A method of making a friction type bearing for a rotary rock bit comprising the steps of:
- turning a journal bearing shaft, forming a cylindrical bearing surface on the shaft, forming a groove around the circumference of the bearing surface, filling only a portion of the groove with a bearing metal, and machining the bearing metal flush with the cylindrical surface.
A method of making a rotary rock bit having a friction type bearing for a cutter cone comprising the steps of:
- turning a journal bearing shaft including a pair of axially spaced apart cylindrical bearing surfaces and a circumferential groove therebetween;
- filling a fraction of the circumference of the groove with bearing metal;
- and
- removing excess bearing metal to form the outer surface thereof flush with the cylindrical bearing surfaces.
A rock bit comprising a drill bit body having a journal bearing spindle shaft, a rotary cutter cone rotatably supported on the shaft, the shaft having a cylindrical bearing portion, the cutter cone having a cylindrical bore extending around the bearing portion for forming a friction bearing, the bearing portion of the shaft having a shallow groove extending around the periphery thereof, bearing metal applied in the groove over less than about half the circumference of the groove and having a load bearing outer surface, a pressure compensating grease reservoir in the bit body, and a passage connecting the grease reservoir to the groove.
A rock bit comprising:
- a bit body;
- a journal bearing shaft on the bit body;
- a rotary cutter cone rotatably supported on the journal bearing shaft and including a cylindrical bore extending around a portion of the journal bearing shaft for forming a friction bearing surface;
- a bearing portion on the journal bearing shaft opposite the cylindrical bore, said bearing portion including a pair of axially spaced apart cylindrical bearing surfaces of hardened steel, a circumferential groove between the cylindrical bearing surfaces, and a bearing metal applied in the groove in only the lower load bearing fraction of the journal bearing shaft and having a load bearing outer surface;
- a lubricant reservoir in the bit body;
- means in the lubricant reservoir for compensating for pressure changes;
- and
- a lubricant passage between the reservoir and the unfilled portion of the circumferential groove.
A method of making a friction type bearing for a rotary rock bit comprising the steps of:
- turning a journal bearing shaft, forming a cylindrical bearing surface on the shaft, forming a groove around the circumference of the bearing surface, filling only a portion of the groove with a bearing metal, and machining an outer load bearing surface on the bearing metal.
A method of making a rotary rock bit having a friction type bearing for a cutter cone comprising the steps of:
- turning a journal bearing shaft including a pair of axially spaced apart cylindrical bearing surfaces and a circumferential groove therebetween;
- filling a fraction of the circumference of the groove with bearing metal;
- and
- removing excess bearing metal to form a load bearing surface on the outer surface thereof.
Dependencies are inferred from the claim text.