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US 9,393,648 B2Granted
Undercut stator for a positive displacment motor
AssigneeSmith International, Inc.
InventorsLance D. Underwood, William D. Murray, Thomas K. Washburn
Life of this patent
Estimating the term…
Abstract
A Moineau style stator includes a stator tube having a plurality of rigid helical lobes formed on an inner surface thereof. The helical lobes define a major internal tube diameter that is greater than a pass through diameter of the tube such that the major diameter undercuts the pass through diameter of the tube. A major liner diameter may also be less than the pass through diameter so as to provide a suitable interference fit between rotor and stator.
Claims5
A Moineau style stator comprising:
- an integral stator tube including a longitudinal end having a threaded box end defining an internal pass through diameter;
- the stator tube defining an internal helical cavity and further including a plurality of internal rigid helical lobes formed on an inner surface of the tube, the helical cavity having a major internal tube diameter that is greater than the pass through diameter of the longitudinal end;
- and
- a resilient liner deployed on an inner surface of the stator tube and presented to the helical cavity,
- wherein the resilient liner defines a major internal liner diameter that is less than the pass through diameter of the longitudinal end.
2 more elements
A subterranean drilling motor comprising:
- a rotor having a plurality of rotor lobes on a helical outer surface of the rotor;
- a stator including an integral stator tube, the stator tube including a longitudinal end having a threaded box end defining an internal pass through diameter, the stator tube defining an internal helical cavity and further including a plurality of rigid helical lobes formed on an inner surface of the tube, the helical cavity having a major internal tube diameter that is greater than the pass through diameter of the longitudinal end, the stator further including a resilient liner deployed on an inner surface of the stator tube and presented to the internal helical cavity, the resilient liner defining a major internal liner diameter that is less than the pass through diameter of the longitudinal end;
- and
- the rotor deployable in the helical cavity of the stator tube such that an outer surface of the rotor is in a rotational interference fit with the resilient liner.
1 more element
Dependencies are inferred from the claim text.