Kinematic And Dynamic Analysis Of Pumping Unit Based On A New Type Of Gear Transmission

Pumping unit is one of the most important equipment in the oil exploitation,on the basis of the investigation and analysis of the current field application,this paper puts forward to improve the energy saving effect of the pumping unit,we should focus on the improvement of the structure,the use of energy-saving electrical equipment,the use of energy-saving components and change the counterbalance of ways and so on.Based on these ideas,a new type of gear transmission pumping unit for low yield oil wells is proposed.And putting forward two kinds of schemes of reversing mechanism of the oil pumping unit,the whole scheme of a new type of gear transmission pumping unit is determined.And then the design and analysis of the selection of pumping unit,the paper mainly includes the following parts:Firstly,the structure design of the new type gear transmission pumping unit is carried out.In the determination of basic parameters of the oil pumping machine based,the motor,a speed reducer,a wire rope and coupling is selected,respectively.Then,the incomplete gear,rack,an incomplete gear shaft,reciprocating frame integral structure,a head sheave,a counterbalance weight,a frame and a shift mechanism is designed,and the three-dimensional model is established.The modal analysis method is used to estimate and optimize the dynamic characteristics of the structure.The lowest natural frequencies are 79.11 Hz and 576.05 Hz,respectively.Analysis of the structure of the natural frequency and the main vibration type,so that its natural frequency is far away from the working frequency of the machine,improved the safety of the machine.The static analysis of the gear rack and pinion is carried out.It is found that the material is not satisfied with the original design,and the material is changed to meet the demand of the gear rack.Therefore,due to the initial design of the impact load can not be considered,after which the components must be analyzed with finite element method,to ensure its safety.Secondly,according to the designed of 3D model of the oil pumping,a mechanical model is established.This is a three freedom degree's mechanical model with forced vibration model of unilateral collision constraint.A Hertz-damp collision model is selected,which have higher accuracy in Engineering,to simulate the collision process.MATLAB/Simulink is used to solve the numerical solution,and the influence of the main parameters on the maximum impactforce and velocity is discussed.After the establishment of one-dimensional wave equation the sucker rod string,the differential form is written;and the difference differential equations boundary conditions are discussed,especially for the new pumping unit,of which is different with the conventional pumping unit,using MATLAB respectively with four equations for fitting.Then the motion diagram of the conventional pumping unit and the new type of gear drive oil pumping unit are analyzed respectively.Finally,analyzed the influence of changing the gear transmission pumping unit stroke,speed,pump diameter and the well fluid viscosity on sucker rod stress.we can draw a conclusion that with the stroke,speed,pump diameter larger,the range of stress fluctuation of sucker rod is larger.Especially when the speed becomes large,the upper end of the oil pumping rod is sharply changed by the alternating stress,which is not favorable for the safety work,so the new oil pumping machine is suitable for low oil recovery.As the fluid viscosity becomes larger,pumping rod stress range becomes smaller,which is different from the conventional pumping unit,mainly due to the special displacement curve of the new pumping unit.