Drill bit having canted seal

• US 6,336,512 B1
• Filed: 02/01/2000
• Issued: 01/08/2002
• Est. Priority Date: 02/02/1999
• Status: Expired due to Term

• Current Assignee: Smith International Incorporated (SLB)
• Original Assignee: Smith International Incorporated (SLB)
• Inventors: Siracki, Michael A., Cawthorne, Chris E., Peterson, Steven W., Nguyen, Quan V.
• Primary Examiner(s): Bagnell, David
• Assistant Examiner(s): DOUGHERTY, JENNIFER R
• Application Number:
  US09/495,602
• Time in Patent Office: 707 Days
• Field of Search: 175/331, 175/359, 175/371, 384/92, 384/94, 227/336
• US Class Current: 175/371
• CPC Class Codes: E21B 10/25 characterised by sealing details

Abstract

A drill bit having a canted or non-canted leg backface, a canted or non-canted seal in the interface between the cone backface and the shirttail, and a canted seal that can be semi-encapsulated so that there is no straight-line path across the seal.

Claims

1. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface and a cone backface, said cone backface defining an interface with said leg backface; and

a seal positioned in said interface, wherein said seal has a frustoconical sealing surface in sealing contact with said journal segment;

said leg backface being canted at an angle of between 35 and 85 degrees with respect to the bearing axis.

2. The bit according to claim 1 wherein said backface is canted at an angle of between 45 and 75 degrees with respect to the bearing axis.

3. The bit according to claim 1 wherein said cone backface is frustoconical.

4. The bit according to claim 1 wherein said shirttail is recessed.

5. The bit according to claim 1 wherein said shirttail is not recessed.

6. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an inner surface, an outer surface and a canted leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a generally conical outer surface and a cone backface, said backface defining an interface with said shirttail inner surface; and

a seal positioned in said interface, wherein said seal has an operating axis and said operating axis is not normal to said canted backface.

7. The bit according to claim 6 wherein sad shirttails recessed.

8. The bit according to claim 6 wherein said shirttail is not recessed.

9. The bit according to claim 6 wherein said seal is a non-positive seal.

10. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an inner surface, an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface, and a backface, said backface defining an interface with said leg backface; and

a canted seal positioned in said interface, said seal having an operating axis that is canted with respect to said bearing axis.

11. The bit according to claim 10, further including a second seal positioned between said journal segment and said cone.

12. The bit according to claim 11 wherein said second seal is canted.

13. The bit according to claim 10 wherein said leg backface is canted.

14. The bit according to claim 10 wherein said shirttail is recessed.

15. The bit according to claim 10 wherein said shirttail is not recessed.

16. The bit according to claim 10 wherein said leg backface is normal to said bearing axis.

17. The bit according to claim 10 wherein said seal operating axis is canted at an angle of between 15 and 45 degrees with respect to said bearing axis.

18. The bit according to claim 10 wherein said seal operating axis is canted at an angle of between 70 and 85 degrees with respect to said bearing axis.

19. The bit according to claim 10 wherein said seal is received in a groove in said cone and bears on said leg backface.

20. The bit according to claim 10 wherein said seal is received partially in a groove in said cone and partially in a cut-out in said leg backface.

21. The bit according to claim 10 wherein said seal is a non-positive seal.

22. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface, and a backface, said backface defining an interface with said leg backface;

a canted seal positioned in said interface, said seal having an operating axis that is canted with respect to said bearing axis; and

said seal has an elongate cross-section and includes a fabric inlay on its wear face.

23. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface, and a backface, said backface defining an interface with said leg backface;

a canted seal positioned in said interface, said seal having an operating axis that is canted with respect to said bearing axis;

said seal is received in a groove in said cone and bears on said leg backface; and

said leg backface includes a wear resistant insert.

24. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface, and a backface, said backface defining an interface with said leg backface;

a canted seal positioned in said interface, said seal having an operating axis that is canted with respect to said bearing axis;

said seal is received partially in a groove in said cone and partially in a cut-out in said leg backface; and

said cut-out includes a wear resistant insert.

25. An earth-boring bit for drilling a borehole, the bit comprising:

a bit body, said body having at least one leg having a journal segment extending inwardly and downwardly therefrom, said leg including a shirttail, said shirttail having an outer surface and a leg backface;

at least one rolling cone cutter rotatably mounted on said bit body and having a bearing axis, a generally conical outer surface and a cone backface, said cone backface defining an interface with said leg backface;

at least two or more independent seals;

at least one of said seals having a frustoconical sealing surface on the journal; and

said leg backface being canted at an angle of between 35 and 85 degrees with respect to the bearing axis.

26. The bit according to claim 25 wherein said leg backface is canted at an angle of between 45 and 75 degrees with respect to the bearing axis.

27. The bit according to claim 25 wherein said cone backface is frustoconical.

28. The bit according to claim 25 wherein said shirttail is recessed.

29. The bit according to claim 25 wherein said shirttail is not recessed.