Fatigue Life Analysis Of The Rack And Pinion Mechanism Of The Pumping Unit

As the key component of the pumping unit,the rack and pinion mechanism of the pumping unit has a direct impact on the safe and reliable operation and service life of the pumping unit equipment.The rack and pinion mechanism of the pumping unit has to withstand high frequency alternating cyclic loads for a long period of time,and the amplitude of the load is relatively large,so fatigue failure will occur.After the mechanism bears the alternating load for a long time,it will produce tiny cracks in the high local stress area of the gear.The cracks will further expand with the operation of the equipment until it breaks,which will cause serious economic losses and even cause casualties.In addition,because the working environment of the pumping unit is relatively harsh,it is very difficult to maintain the equipment in the Gobi Desert,desert and other areas.It is of great significance to study the meshing characteristics and fatigue life analysis of the rack and pinion mechanism of the pumping unit.This paper takes the rack and pinion mechanism of pumping unit as the research object,and studies the fatigue life of the rack and pinion mechanism under actual working conditions.The main analysis of the mechanism is as follows: The static and dynamic meshing mechanics at different positions of the gear mechanism Characteristic analysis;fatigue life characteristics under different operating conditions;fatigue life characteristics under different fatigue conditions.First,the contact theory is used to analyze the contact types of the rack and pinion mechanism,and a finite element contact model is established to provide a theoretical basis for the finite element analysis of the rack and pinion mechanism.Secondly,construct a simplified three-dimensional model of the rack and pinion mechanism,divide it into a high-quality hexahedral mesh,and obtain its mode shape and vibration frequency distribution through modal analysis of the mechanism,indicating that the mechanism has good rigidity and displacement and deformation.Smaller,the meshing frequency of the rack and pinion is lower than the excitation frequency,and the mechanism is less likely to resonate under normal working conditions;through the static analysis of the mechanism,the maximum stress position of the gear is mainly concentrated near the index circle,The stress of the rack is mainly concentrated at the meshing position of the gear.The equivalent strain of the gear during operation is small,indicating that the plastic deformation generated by the mechanism is small,and the displacement and deformation of the gear in the transition section and the straight section are small.The displacement and deformation of the section are large.Finally,using the nominal stress method and the Miner linear cumulative damage theory to analyze the fatigue life of the rack and pinion mechanism,it is concluded that the gear has greater fatigue damage in the transition section and the straight section,and the commutation section has less fatigue damage.The influence of roughness and stress correction on the fatigue life of the mechanism.