Abstract: The screw machine comprises consecutively mounted screw mechanisms (6, 7 and 8, 9) incorporating coaxially arranged stators (10, 12 and 14, 16) and rotors (11, 13 and 15, 17) disposed therein whose axes are offset with respect to the central axis of the stators (10, 12 and 14, 16) by the amount of eccentricity "e" of the screw mechanisms (6, 7 and 8, 9). The screw mechanisms (6, 7 and 8, 9) are grouped into modules (4, and 5) and the modules proper are grouped into blocks (3). The axes of the rotors (11, 13, 15, 17) of the screw mechanisms (6, 7 and 8, 9) in the module (4 and 5) and the modules (4, and 5) proper in the block (3) are arranged symmetrically relative to the central axis.

Abstract: A downhole motor includes a bearing unit connected to a moving section incorporating successively arranged working members--a stator and a rotor interacting with each other along profile surfaces. The like pairs of the adjacent working members are rigidly connected to each other by means of solid threaded bushings. A mounting fixture includes two mounting elements each made as two bushings interconnected by a coupling, the bushings having their profile surfaces located on the same longitudinal axis. One of the bushings is rigidly connected to the coupling, while the other bushing is mounted with the possibility of moving with respect to the longitudinal axis. A method of assembling the downhole motor is effected with the use of a pre-adjusted mounting fixture and resides in interconnecting the like working members by thread bushings ensuring the arrangement of the profile surfaces of the working members analogously to the profile surface of the single monolithic rotor and stator.

Abstract: A helical down-hole machine comprises a plurality of sections, each such section having a helical rotor and a helical stator arranged with a preselected eccentricity to form cavities of variable volume for the passage of fluid therethrough and positioned axially in series. The identical elements of these sections, rotors or stators, are rigidly interconnected. The rigid connection of at least one of these identical elements of said sections is detachable by frictionally jointing a projection provided at the end of one such element and a recess provided at the end of the adjacent element to be secured against relative angular and axial displacements in the process of rotation.

Abstract: A multistart helical planetary gear motor, comprising a stator 3 having an internal helical thread and a rotor 4 having an external helical thread and arranged eccentrically within the stator 3. The rotor 4 and stator 3 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 3 and the rotor 4 is directly proportional to the ratio of their respective numbers of teeth. The ratio of pitches of the helical surfaces of the stator 3 and the rotor 4 to their respective pitch diameters ranges substantially from 5.5 to 12.

Abstract: In a reduction unit of a drilling motor comprising a casing, input and output shafts installed on supports, a reduction gear including sun and crown wheels, pinion carriers and planet pinions with supports located in a circular space between the wheels, an oil-filled chamber and a system of oil protection, there is provided a means eliminating the overloading of the reduction gear and a means eliminating the effect of torque fluctuations on the operation of the reduction gear while the supports of the input and output shafts installed on the ends of said shafts connected with the reduction gear are made in the form of articulated units taking axial loads and permitting angular displacements of the shafts, each of said shafts carrying a seal installed side by side with said support at the side opposite to the reduction gear, said seal being provided with a dividing space filled with a buffer fluid which protects said seal against contact with the drilling fluid.