<p>BOTTOM-HOLE MULTISTART SCREW MOTOR A multistart helical planetary gear motor, comprising a stator having an internal helical thread and a rotor having an external helical thread and arranged eccentrically within the stator. The rotor and stator form a kinematic couple which is in permanent engagement similarly to an internal gearing, with the number of the stator teeth being greater than the number of rotor teeth by unity. The ratio of pitches of the helical threads of the stator and rotor is directly proportional to the ratio of their respective numbers of teeth. The ratio of pitches of the helical surfaces of the stator and rotor to their respective pitch diameters ranges substantially from 5.5 to 12.</p>
