SCREW DOWNHOLE MOTOR Russian patent published in 1995 - IPC

FIELD: mining. SUBSTANCE: screw downhole motor has motor section with lower sub, spindle section and unit for their joint in form of torsion bar with half-coupling on lower end. Outer surface of torsion bar half-coupling has projections with ports to pass srilling mud. Inner hollow of lower sub has annular shoulder engageable with half-coupling projections. There is gap between projections and shoulders in axial and radial directions in motor operating position. EFFECT: higher efficiency. 3 dwg