Down hole harmonic drive transmission

摘要

A drilling assembly positionable in a well bore includes a turbine motor couplable to a drill string and a harmonic drive transmission coupled to the turbine motor. The harmonic drive transmission includes a circular spline, a wave generator, a flexspline, and a sealing subsystem. The sealing subsystem defines a substantially sealed volume containing the circular spline, wave generator, and flexspline, and isolates the circular spline, wave generator, and flexspline from drilling fluid exiting the turbine motor and flowing through the harmonic drive transmission.

主权项

1. A drilling assembly positionable in a wellbore, the assembly including:
a turbine motor couplable to a drill string; and a harmonic drive transmission coupled to the turbine motor, the harmonic drive transmission comprising:
a circular spline;a wave generator coupled to an input shaft;a flexspline coupled to an output shaft;a sealing subsystem including:
an upper rotary seal disposed around the input shaft;a lower rotary seal disposed around the output shaft; anda drilling fluid diversion subsystem comprising a drilling fluid flow path including a drilling fluid inlet on the input shaft leading to a bore of the input shaft, and a drilling fluid outlet on the output shaft leading to a bore of the output shaft, the input shaft extending through a central opening defined by a central passage of the wave generator, a central passage of the flexspline, and a central passage of the circular spline to couple with the output shaft, such that the bore of the input shaft is in fluid communication with the bore of the output shaft.