Protector for rock bit seals

• US 20080073124A1
• Filed: 09/21/2006
• Published: 03/27/2008
• Est. Priority Date: 09/21/2006
• Status: Active Grant

• Current Assignee: Baker Hughes Holdings LLC (Baker Hughes Company)
• Original Assignee: Baker Hughes Incorporated (Baker Hughes Company)
• Inventors: Lin, Chih C.
• Granted Patent: US 7,628,231 B2
• Time in Patent Office: Days
• US Class Current: 175/371
• CPC Class Codes: E21B 10/22 characterised by bearing, lubrication or sealing details

Abstract

An earth-boring bit has a bit body with a depending bearing pin and a cone rotatably mounted thereon. A seal seals between the bearing pin and the cone. An annular set of bristles is located adjacent at least part of the dynamic seal surface of the seal to protect the seal against debris.

Claims

1. An earth boring bit, comprising:

a bit body having a depending bearing pin;

a cone having a plurality of cutting elements for engaging a bore hole, the cone having a cavity that rotatably engages the bearing pin, the cone and the bearing pin having a seal area defined by two annular surfaces, one of which rotates relative to the other;

A seal in sealing engagement with the annular surfaces of the seal area; and

a debris protector having a porous surface substantially in sliding contact with one of the annular surfaces.

2. The bit according to claim 1, wherein the porous surface comprises a set of bristles.

3. The bit according to claim 1, wherein the debris protector rotates with the cone.

4. The bit according to claim 1, wherein the debris protector is mounted to the seal.

5. The bit according to claim 1, wherein:

the seal comprises an elastomeric ring having an inner diameter surface in sliding engagement with the bearing pin; and

the debris protector is located on a drilling fluid side of at least part of the inner diameter surface.

6. The bit according to claim 1, wherein the porous surface of the debris protector is annular.

7. The bit according to claim 1, wherein:

the seal comprises an elastomeric ring having at least one surface in sliding engagement with the bearing pin; and

the debris protector is mounted to the ring on a drilling fluid side of said at least one surface.

8. The bit according to claim 1, wherein:

the debris protector is mounted to the cone for rotation with the cone.

9. The bit according to claim 8, wherein:

the seal area comprises a groove formed in the cavity of the cone;

the seal comprises an elastomeric ring located in the groove;

the debris protector is stationarily fixed to the cavity of the cone rearward from the groove; and

a spacer washer is located between a rearward side of the seal and a side wall of the groove.

10. An earth boring bit, comprising:

a bit body having a depending bearing pin;

a cone having a plurality of cutting elements for engaging a bore hole, the cone having a cavity that rotatably engages the bearing pin;

a seal between the bearing pin and the cone, the seal having at least one seal surface that slidingly and sealingly engages the bearing pin; and

an annular brush located on a drilling fluid side of said at least one seal surface, the brush rotating relative to the bearing pin and having an inner diameter substantially equal to an outer diameter of the bearing pin.

11. The bit according to claim 10, wherein the brush is mounted to the seal for rotation therewith.

12. The bit according to claim 10, wherein:

the seal comprises an elastomeric ring having an inner diameter portion; and

the brush is mounted to the inner diameter portion of the seal.

13. The bit according to claim 10, wherein:

the seal is located within a groove formed in and spaced from a mouth of the cavity; and

the brush is mounted to the cone for rotation therewith between the groove and the mouth of the cavity.

15. The bit according to claim 10, wherein:

said at least one seal surface comprises two of the seal surfaces, each located within an inner diameter portion of the seal; and

the brush is mounted in the inner diameter portion of the seal between the seal surfaces.

17. The bit according to claim 15, wherein:

when the seal is in a relaxed condition, the seal surfaces have inner diameters that are substantially the same as the inner diameter of the brush.

18. The bit according to claim 10, wherein:

said at least one seal surface comprises a single seal surface located within an inner diameter portion of the seal; and

the brush is mounted to the inner diameter portion of the seal on a drilling fluid side of the seal surface.

14. The bit according to claim 14, further comprising:

a spacer washer located within the groove between the seal and the brush, the spacer washer having an inner diameter substantially equal to an inner diameter of the brush.

16. The bit according to claim 16, wherein:

when the seal is in a relaxed condition, the seal surfaces have inner diameters smaller than the inner diameter of the brush.

19. A method of sealing drilling fluid from lubricant in an earth boring drill bit having a cone rotatably mounted on a bearing pin for engaging a borehole, comprising:

providing a seal area between the cone and the bearing pin defined by two annular surfaces, one of which rotates relative to the other, mounting a seal between the annular surfaces, the seal having at least one dynamic seal surface, and mounting a debris protector adjacent to a drilling fluid side of the dynamic seal surface;

rotating the cone on the bearing pin within a borehole and sealing drilling fluid in the borehole from lubricant with a dynamic seal surface of the seal; and

permitting any drilling fluid that contacts the debris protector to migrate past the debris protector into contact with the dynamic seal surface, but blocking with the debris protector at least some debris of the drilling fluid from reaching the dynamic seal surface.

20. The method according to claim 19, further comprising:

providing the seal with two of the dynamic seal surfaces and positioning the protector between the dynamic seal surfaces; and

permitting any lubricant that leaks past one of the dynamic seal surfaces to migrate past the debris protector into contact with the other of the dynamic seal surfaces, but blocking with the debris protector at least some debris of the lubricant from reaching the other of the dynamic seal surfaces.