PCD face seal for earth-boring bit
AssigneeBaker Hughes Incorporated
InventorsChih Lin, Terry Koltermann, Danny Scott
Life of this patent
Estimating the term…
Abstract
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 cemented carbide body and an annular PCD face located on it. The mating face may also be of a PCD material. The cemented carbide body contains a binder that migrates into the PCD face while the PCD face is being formed. A binder-free region is leached on the surface of the PCD face.
Claims20
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
- a bit body;
- at least one cantilevered bearing shaft extending inwardly and downwardly from the bit body;
- at least one cone mounted for rotation on the bearing shaft;
- and
- a seal assembly disposed between the bearing shaft and the cone, the seal assembly including at least one rigid seal ring concentric with the bearing shaft;
- the seal ring having a body of cemented carbide;
- an annular PCD layer located on the body;
- a binder material selected from a group consisting of cobalt, nickel and alloys thereof interspersed within the cemented carbide and within the PCD layer;
- and
- the PCD layer having an exterior surface with an annular binder-free region of a selected depth within the PCD layer that is substantially free of the binder material, the depth of the binder-free region being less than the thickness of the PCD layer.
(canceled)
An earth-boring bit with an improved mechanical face seal assembly, the earth-boring bit comprising:
- a bit body;
- at least one cantilevered bearing shaft extending inwardly and downwardly from the bit body;
- at least one cone mounted for rotation on the bearing shaft;
- lubricant located in bearing spaces between the bearing shaft and the cone;
- and
- a seal assembly disposed between the bearing shaft and the cone for sealing the lubricant within the bearing spaces, the seal assembly including first and second seal rings, each of the first and second rings having a body having a continuous annular PCD layer located thereon, the PCD layer of each of the rings having an exterior surface that contacts the exterior surface of the other of the seal rings;
- the body of each of the rings being formed of tungsten carbide and a binder selected from a group consisting of cobalt, nickel and alloys thereof;
- a portion of the binder being located in the PCD layer of each of the rings;
- and
- the PCD layer of each of the rings having a leached layer at the exterior surface that is substantially free of the binder and extends to a selected depth within the PCD layer the depth of the leached layer being less than the thickness of each of the PCD layers.
(canceled)
A seal ring for an earth-boring bit, comprising:
- an annular body of cemented carbide containing a binder material from a group consisting of cobalt, nickel and alloys thereof;
- a continuous annular PCD layer formed on the body, the PCD layer containing a portion of the binder material that has migrated from the cemented carbide while the PCD layer was being formed;
- and
- the PCD layer having an annular binder-free region that extends to a selected depth within the PCD layer and is leached substantially free of the binder material, the selected depth being less than the thickness of the PCD layer.
Dependencies are inferred from the claim text.