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US 6,684,966 B2Granted
PCD face seal for earth-boring bit
AssigneeBaker Hughes Incorporated
InventorsChih Lin, Terry Koltermann, Danny E. Scott
Life of this patent
Estimating the term…
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AssigneeBaker Hughes Incorporated
InventorsChih Lin, Terry Koltermann, Danny E. Scott
Estimating the term…
An earth-boring bit has a mechanical face seal assembly with PCD faces. The bit has a bearing shaft with a cone rotatably mounted on the bearing shaft. The seal locates between the bearing shaft and the cone for sealing lubricant therein. The seal includes at least one rigid seal ring having a carbide body and an annular PCD face located on it. The mating face may also be of a PCD material.
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
Dependencies are inferred from the claim text.
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From the US filing history. Foreign family members aren’t listed.
Characterised by bearing, lubrication or sealing details: characterised by sealing details
Parts of bearings; Special methods for making bearings or parts thereof: sealings
With slip-ring pressed against a more or less radial face on one member: use of special materials
Apparatus for drilling
Term ended 9 Jan 2022 (estimated)
This invention relates in general to earth-boring bits of the roller cutter variety. More particularly, the invention relates to a seal assembly for sealing lubricant within the bit and excluding drilling environment without the bit, the seal assembly having a polycrystalline diamond (PCD) face.
One of the most successful seal means used in earth-boring bits of the type having rotatable cutters is the O-ring seal disclosed in commonly assigned U.S. Pat. No. 3,397,928, to Galle. The o-ring seal successfully confines lubricant to the bearing area while excluding detritus for long periods of time before failure.
A more recent seal development is the rigid or metal face seal. In the rigid face seal type, the seal interface is between one or two rigid, usually steel, seal rings. One or two elastomer o-rings serve to energize or urge the seal faces of the rigid ring or rings in contact with each other. The rigid face seal has proved to be as successful as the o-ring seal and provides improved durability in high rotational speed applications.
FIG. 1 is a longitudinal sectional view of one leg of an earth-boring bit having a seal assembly in accordance with this invention.
FIG. 2 is an enlarged sectional view of the seal assembly of FIG. 1.
FIG. 3 is a further enlarged view of the mating faces of the seal assembly of FIG. 2, with diamond layers shown exaggerated in thickness.
Referring to FIG. 1, bit 11 has a body 13. Body 13 has a leg with a depending bearing pin 15 extending downward and inward. Bit 11 of the embodiment shown will have as many as three bearing pins 15, but only one is shown. A cone 16 is rotatably mounted to each bearing pin 15. Cone 16 has a plurality of external teeth that may be integrally formed with the body of cone 16, or formed of tungsten carbide and pressed into holes, as shown.
The bearing spaces between bearing pin 15 and cone 16 are filled with a lubricant 18 (FIG. 2). A lubricant compensator 17 equalizes pressure on the exterior of bit 11 with the pressure of lubricant 18 contained in the bearing spaces. A seal assembly 19 located near the base of bearing pin 15 seals lubricant 18 within the bearing spaces.
Referring to FIG. 2, in the preferred embodiment, seal assembly 19 includes a rigid ring 21 surrounding bearing pin 15 near the base of bearing pin 15. Rigid ring 21 is urged into sliding contact with an annular insert 23, which is a ring or sleeve shrink-fit into the cavity of cone 16. Insert 23 rotates in unison with cone 16, while rigid ring 21 remains stationary with bearing pin 15. An energizing elastomer 25 is deformed between an inner diameter surface 27 of rigid ring 21 and seal cavity 29. Energizing elastomer 25 exerts a force on rigid ring 21 against insert 23. Energizing elastomer 25 also seals lubricant 18 located within the bearing spaces. In this embodiment, an excluder elastomer 31 is also utilized. Excluder elastomer 31 is deformed between a portion of seal cavity 29 in bearing pin 15 and both energizing elastomer 25 and an end of rigid seal ring 21. Excluder elastomer 31 serves to prevent the entry of debris into contact with energizing elastomer 25.