Earth-boring drill bits with controlled cutter speed across the bit face, and related methods
AssigneeBaker Hughes, A Ge Company, LLC
InventorJon David Schroder
Life of this patent
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Abstract
An earth-boring drill bit includes a bit body including a central shaft having a longitudinal axis, an annular cutter body disposed around, and rotatable relative to, the central shaft, at least one gear assembly operatively coupling the annular cutter body to the central shaft, a first cutter disposed on the central shaft at a first distance from the longitudinal axis, and a second cutter disposed on the annular cutter body at a second, greater distance from the longitudinal axis. Methods of fabricating earth-boring drill bits include rotatably coupling at least one annular cutter body to a central shaft, the at least one annular cutter body and the central shaft being concentric.
Claims20
An earth-boring drill bit, comprising:
- a bit body including a central shaft and having a longitudinal axis;
- an annular cutter body disposed around the central shaft and rotatable relative to the central shaft about the longitudinal axis;
- at least one gear assembly operatively coupling the annular cutter body to the central shaft;
- a first cutter disposed on the central shaft at a first distance from the longitudinal axis;
- and
- a second cutter disposed on the annular cutter body at a second, greater distance from the longitudinal axis of the central shaft, wherein the at least one gear assembly is sized and configured to result in a linear speed of the second cutter that is within about 10% of a linear speed of the first cutter when the earth-boring drill bit is in use to form a borehole.
An earth-boring drill bit assembly, comprising:
- a downhole motor;
- a central shaft operatively coupled to the downhole motor, the central shaft comprising a longitudinal axis, one or more cutters, and a sun gear circumscribing the central shaft and centered on the longitudinal axis;
- a first annular cutter body disposed around and rotatable relative to the central shaft, the first annular cutter body comprising one or more additional cutters and one or more planetary gears rotatably mounted on the first annular cutter body and engaged with the sun gear;
- and
- a second annular cutter body disposed around the first annular cutter body and the central shaft and comprising:
- one or more additional planetary gears rotatably mounted on the second annular cutter body and engaged with another sun gear disposed on the first annular cutter body;
- and
- an internal gear extending inward from the second annular cutter body and engaged with the one or more planetary gears rotatably mounted on the at least one annular cutter body.
A method of fabricating an earth-boring drill bit, comprising:
- rotatably coupling at least one annular cutter body to a central shaft, the at least one annular cutter body and the central shaft being concentric;
- rotatably coupling at least one planetary gear to the at least one annular cutter body;
- engaging the at least one planetary gear with a central sun gear on the central shaft;
- positioning a first group of cutters on the central shaft at a first distance from a central longitudinal axis of the central shaft;
- and
- positioning a second group of cutters on the at least one annular cutter body at a second, greater distance from the central longitudinal axis of the central shaft, wherein the at least one annular cutter body and the second group of cutters are configured to rotate at a second, slower rotational speed relative to a first rotational speed of the central shaft and the first group of cutters.
Dependencies are inferred from the claim text.