Analysis And Optimization Of Mechanical Characteristics Of Main Test Chamber System Of Fatigue Test Machine

Contact fatigue is one of the main causes of failure of basic components such as gears and bearings.According to the industry standard(YB / T 5345-2014),the rolling contact fatigue testing machine is an indispensable test equipment for obtaining material rolling contact fatigue performance,and the main test chamber is the core component of the testing machine Therefore,the analysis and optimization of the system characteristics of the main test chamber are of great significance for the development of fatigue testing machines.In this paper,the main test chamber system of the rolling contact fatigue testing machine independently developed is taken as the object,and the dynamics of the single cylindrical roller bearing is used as the entry point.design.The main research work of the paper includes:1.According to the Hertz contact theory,the contact parameters are determined in combination with the actual working conditions of the bearing.The movement law of the cylindrical roller bearing is analyzed,and the theoretical rotation speed of the cage is derived.According to the actual constraint relationship,the dynamic model of cylindrical roller bearing is established in ADAMS,and the model verification is completed.On this basis,the effect of radial load and rotation speed on cylindrical roller bearings is explored.The results show that the stability of the bearing cage changes with the increase of the radial load under the condition that the rotation speed and axial preload are constant.Poor,but the contact force between the rolling element and the outer ring increases and tends to be stable,and the instantaneous impact is suppressed;under the condition of a certain radial load and axial preload,the contact force between the rolling element and the outer ring increases as the speed increases The period is obviously shortened,and the instantaneous shock is increased.2.Taking the main test box system as the object,based on the analysis of the main test box structure characteristics and bearing characteristics,combined with the multi-body dynamics method,considering the box body and the main shaft as the spatial flexible body,the rigid-flexible coupling dynamics of the main test box is established model.The validity of the model is verified by comparing the theoretical and simulated values of the cage rotation speed and the test and analysis of the vibration signal of the box.3.Relying on the established rigid-flexible coupling dynamic model of the main test chamber,the dynamic characteristics analysis of the main test chamber system was completed,and the effects of different rotation speeds and different radial loads on the spindle vibration were explored.The results show that as the speed increases,the vibration intensifies and the rate of change increases;the radial load and the vibration are not a simple linear relationship.Under the radial load of 5kN-12.5kN,the system vibration can be suppressed;the limit conditions The deformation of the lower main shaft is large,and the structure needs to be further optimized.4.In view of the extreme deformation of the main shaft under extreme conditions,the main shaft was optimized from the structural rigidity and bearing stiffness.On this basis,the multi-objective optimization method was used to complete the optimal design of the box.The results show that the static and dynamic characteristics of the spindle system after the optimization meet the design requirements;the weight of the cabinet is reduced by 18.1%,and the expected optimization goal is achieved.