| 摘要 |
An actuator 100 to direct a rotary steerable drilling tool, includes a stator 102 having an internal cavity 110 and an armature 104. The armature is configured to be electromagnetically displaced into one of three stable positions. The cavity is in communication with a high-pressure fluid zone and two hydraulic ports 106, 108. The high-pressure zone may be provided by drilling fluids. Either or none of the ports are blocked, preferably with plungers 118, 120 on the armature, allowing for three different control options. In a second aspect, a method to operate a rotary steerable tool with an actuator is provided. Alternatively, a tri-stable actuator includes an armature held in first and second stable positions by a force of fluids flowing from a high-pressure zone through either of a first or a second port. |
