SCREW DOWNHOLE MOTOR Russian patent published in 2000 - IPC

FIELD: drilling of gas and oil wells. SUBSTANCE: profile of tooth of rotor and stator is made by arc of circumference describing addendum part of tooth and two arcs of circumferences describing dedendum part of tooth, centers of circumferences being located on axis of symmetry of dedendum part of tooth and addendum part of tooth, respectively. Points of centers of circumferences of addendum and dedendum parts of tooth and mating point are located on one straight line, and angles between tangential lines in top and bottom points of profile and straight lines drawn from center of rotor or stator and angle formed by tangential line point of intersection of arcs of circumferences describing addendum and dedendum parts of tooth and straight line passing through centers of these arcs are equal to 90, rations of radii of circumferences describing addendum and dedendum parts of tooth are within 0.08 - 2.5, respectively. EFFECT: simplified designing of teeth of rotor - stator pair, improved performance characteristics of motor. 3 dwg