GEROTOR MECHANISM OF SCREW DOWNHOLE MOTOR Russian patent published in 2009 - IPC F01C1/16 E21B4/02 

FIELD: motors and pumps.

SUBSTANCE: gerotor mechanism of screw downhole motor contains stator and rotor. The stator is implemented as inner spiral teeth made from visco-elastic material. The rotor is provided with outer helical teeth. The number of the latter is less than the number of stator teeth by one tooth. The pace between helical lines on rotor and stator teeth is proportional to the number of corresponding teeth. The cross section area of the inner helical visco-elastic stator teeth repeats the shapes of the equidistant curtail cycloids and depends on a value of radial and disturbing forces. The modified profile of rotor is made according to equidistant curtail cycloid and crosses three correlating points forming rotor profile.

EFFECT: high bending stiffness of stator teeth.

2 cl, 8 dwg, 7 tbl