SCREW DOWNHOLE MOTOR Russian patent published in 2006 - IPC E21B4/02 F01C1/16 F04C2/00 

FIELD: drilling equipment, particularly screw downhole motors for oil and gas well drilling and repair.

SUBSTANCE: screw downhole motor comprises stator with inner helical teeth and rotor with outer helical teeth. Number of outer helical teeth is one less than that of stator. Outer rotor teeth profile and inner stator teeth profile envelope each other. Rotor and stator teeth chords are proportional to number of teeth thereof. Rotor is made of laminated profiled rope having metal, for instance steel, covering. The metal covering is connected directly to rotor by mechanical covering compression or with the use of intermediate material placed between the rotor and the covering, namely with the use of thermosetting plastics or glue. Working rotor surface may be coated with material selected from antifriction materials, for instance with polyamide or rubber, here the stator may have metal teeth. Profiled rotor rope is made of metal wire and has metal core.

EFFECT: increased performance, possibility of rotor profile self-alignment with stator profile, elimination of manufacturing rotor curvature error influence on motor operation, as well as simplified production technique.

8 cl, 5 dwg