Rotor bearings for Exzenterschneckenbohrlochbohrmotor

A Exzenterschneckenbohrmotor which can be disposed in a wellbore includes a tubular housing, a stator with a set of helical wings and a rotor having a set of helical wings. The rotor revolves around the central longitudinal axis of the stator. A bearing assembly coupled to one end of the housing and is arranged around one end of the rotor. The bearing assembly includes a bearing housing which is concentrically arranged in the stator housing, an outer bearing which is concentrically disposed in the bearing housing, and an inner bearing, which is arranged on said first cylindrical end of the rotor. The inner bearing has a central axis which is aligned with the central axis of the rotor and is arranged in the outer bearing, that the inner bearing revolves around the central longitudinal axis of the stator when the rotor is rotated in the stator.