Abstract
Oil production enterprises in Ukraine mainly use traditional balance drives, which have proven their reliability over many years of operation. New drive schemes, in terms of efficiency, require a comparative assessment of their characteristics with balance drives. For the purpose of comparative analysis and calculation of the kinematic parameters of the crank-pulley drive, which was operated at the Oil and Gas Production Department Okhtyrkanaftogaz of the Public Joint Stock Company Ukrnafta from 1993 to 2021, the paper presents the development of its mathematical model. For this purpose, geometric dependencies were used to calculate the length of the rope, which acts as a flexible link, and, accordingly, the displacement of the rod suspension. By differentiating the displacement graph, the corresponding kinematic characteristics were obtained – velocities and accelerations, which are components for calculating the moment of resistance forces reduced to the crank of the executive mechanism. The coefficients of mean square deviation calculated for traditional sucker-rod pumping units and crank-pulley drives allowed a comparative assessment of their balancing quality. Their characteristics were compared based on the load of the executive mechanism using a typical static dynamogram, since the accepted rotation speed of the crankshaft of sucker-rod pumping unit is less than 8 rpm. It was determined that the root mean square deviation of the torque of the crank-pulley drive was 9.47 kN×m, which is 33.6% less than that of a traditional balancing drive. Using a developed mathematical model, which employs the vector contour method, a system of linear equations was obtained to determine the dependence of the rotation angle j2 of the lower crossbar, to which the rope is attached, and the rotation angle j3 of the movable pulley on the rotation angle j1 of the crank. It has been established that the movable pulley changes its direction of movement twice per revolution of the crank of the executive mechanism, which may be the cause of accelerated wear of the drive rope