| Conventional beam pumping units are used widelist in the mechanical oil pumping field,and they hold a gteat importance in this field, but thier efficiency is too low and they consumes too much energy which have become one of the equipments that consume most electric power. Therefore, an intensive study on the transmission efficiency of beam-pumping unit is very necessary. Traditional research method focused on two fields, one based on theoretical calculation and for ease of calculation they have done some simplification, so it has many limitations. The other one take the practical situation into consideration, found out the major factors that influence transmission efficiency and in connection with these factor they have gave similar measures which will be good for increasing the transmission efficiency. But that method could't give a more accurate value of transmission efficiency and it only can have a value in a restricted range.So it also has many limitations.In connection with the limitations of the traditional methods, this paper divide the transmission efficiency of pumping units into gears, belts and bearings. And use the method that numerical simulation integrated with experimentalize to research the transmission efficiency of pumping units.In the aspects of numerical simulation, this paper firstly constructed three parametric models of gear, belt and bearing using 3-D modeling software which based on Pro/E and in order to do finite element analysis then the models were actually imported to ANSYS Workbench software through proprietary interface, then discrete entity model into finite element model in ANSYS Workbench software. Transient dynamic method was employed, the application of boundary conditions was based on the actual operation situation and fully considered the motion, contact, friction an so on of the component. The nonlinear dynamic finite element model of the gear transmission system, belt transmission system, bearing drive system are established and according to the boundary conditions which are applied in the mode the value of the gear and belt transmission efficiency and the power loss value of friction bearings are obtained.In the aspects of experimental research, this paper take the on-site beam pumping units as the major research object and used Torque Telemetry technology which get the motor input /output power, gearbox input / output shaft torque and the data of power, polished rod displacement and indicator diagram at the same time. And then get average transmission efficiency and instantaneous transmission efficiency of the beam pumping unit's electrical motor, belt, positive speed gearbox, four- bar linkage and complete appliance. The data indicate that the efficiency declined when the transmission efficiency of the beam pumping unit reach the data that near the peak value, or we can say the efficiency declined when the tendency of the load value changes. The efficiency value can fluctuate when the load direction changes and may appear unusual value of efficiency. So the transmission efficiency of the beam pumping unit is not a fixed value during a complete stroke but get a change with the alternate polished rod load of the pumping unit.
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