| 摘要 |
A fluid powered incremental stepping motor arranged to serve as a length of pipe string has a body that includes an arbor end with an arbor of reduced diameter extending into a bore of a housing end bearingly supported for rotation about the arbor. An annular space between arbor and housing contains a piston rotationally secured to the arbor for limited axial movement. The piston operates within the bore as a power cylinder and carries a flow resistor. Fluid channels extend through the body to accept fluid flow down the pipe string. Fluid flow urges the piston downward and a spring urges it upward. Cams on each end of the piston and mating cams in the housing bore engage at the upward and at the downward extreme of piston travel and at each engagement impart an increment of rotation of the housing relative to the arbor at each excursion of the piston. Increasing fluid flow down the pipe string and then decreasing the flow causes the piston to reciprocate at each flow rate change cycle. The housing then is caused to rotate in steps as long as the flow rate cycling continues.
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