Magnetic gear for use with wellbore instruments

摘要

A wellbore rotating instrument system includes a source of rotational energy for transmission thereof to within a wellbore. At least one magnetic gear assembly is coupled at its input to an output of the source. A rotating load is coupled at its input to a rotational output of the magnetic gear assembly. The at least one magnetic gear assembly comprises a housing, a stator disposed in the housing proximate an inner wall thereof, a second shaft rotatably supported on bearings disposed at longitudinally spaced apart locations inside the housing and a first shaft rotatably supported inside the output shaft. The stator comprises a plurality of magnets disposed in generally circular laminations. The second shaft comprises a non-magnetic, electrically non-conductive body and a plurality of pole pieces disposed circumferentially therearound. The first shaft comprises magnets disposed around its exterior circumference and shaped to fit rotatably within the second shaft.

主权项

1. A wellbore rotating instrument system, comprising:
a source of rotational energy communicable at a rotary output of the source to a selected axial position within a wellbore; at least one magnetic gear assembly disposed in the wellbore and coupled at a rotary input of the source to an output of the source; a rotating load instrument disposed in the wellbore and functionally coupled at a rotary input of the rotating load instrument to a rotational output of the magnetic gear assembly; wherein the at least one magnetic gear assembly comprises a housing, a stator disposed in the housing proximate an inner wall thereof, a second shaft rotatably supported on bearings disposed at longitudinally spaced apart locations inside the housing and a first shaft rotatably supported inside the second shaft; and wherein the stator comprises a plurality of magnets disposed in a plurality of generally circular laminations, wherein the second shaft comprises a non-magnetic, electrically non-conductive body and a plurality of pole pieces disposed circumferentially around an exterior circumference of the body, and wherein the first shaft comprises a plurality of magnets disposed around an exterior circumference thereof and shaped to fit rotatably within an interior of the second shaft, wherein the body of the second shaft comprises a composite material and wherein the body of the second shaft comprises a shaft extension at each longitudinal end, a metal ring fit over each extension, and a tapered coupling press fitted, bonded and welded into an interior of each extension.