| 摘要 |
A torque control device 110 for a downhole drilling assembly adapted for connection to a drill bit includes an outer sleeve 132 and an inner shaft 60, the outer sleeve 132 being movable longitudinally relative to the inner shaft 60. The torque control device has a cylinder 146, a piston 140 located within the cylinder 146, and a rotary valve 136, 66 to control the volume of the cylinder 146. The volume of the cylinder 146 can be changed by way of the rotary valve 136, 66 whereby to adjust the weight on bit and thereby control the torque upon the drill bit. |
