DOWNHOLE DRILLING MOTOR AND METHOD OF USE Russian patent published in 2017 - IPC E21B4/02 

FIELD: mining.

SUBSTANCE: downhole drilling motor comprises a tubular housing in a drill string, the first elastomeric stator formed on the inner housing surface and having the first cavity of helical shape with formed therein the first number of entries, the dual-purpose hollow-core construction of helical form, located inside the first elastomeric stator and having the second number of goes, formed on the outer surface to form the first rotor. The second number of entries of the first rotor is one fewer than the first number of entries of the first stator, the second elastomeric stator formed on the inner surface of the dual-purpose hollow element of helical shape and having the second cavity of helical shape with the third number of entries, the second rotor of helical shape, located inside the second helical cavity and having the fourth number of entries, which is one less than the third number of entries, the flow switch in the housing upper end arranged to guide the drilling fluid through one of the cavities from the group consisting of the first and second cavity of helical shape, as well as through the first cavity of helical form and through the second cavity of helical shape, the first flexible shaft operatively connected to the lower end of the hollow element of helical shape and the second flexible shaft operatively connected to the lower end of the second rotor of helical shape.

EFFECT: ability to change the fluid flow rate or bit rotational speed outside of the design range for the drilling motor in the drill string.

10 cl, 5 dwg