Optimized liner thickness for positive displacement drilling motors

摘要

A stator for a positive displacement motor including an external tube. The external tube includes an outer surface and an inner surface, and the inner surface includes at least two radially inwardly projecting lobes extending helically along a length of the external tube. A liner is positioned adjacent the inner surface, and the liner conforms to the radially inwardly projecting lobes formed on the inner surface and to the helical shape of the inner surface. A thickness of the liner is at a maximum at the at least two radially inwardly projecting lobes.