High Frequency Crank Slider Mechanism Dynamic And Temperature Field Research

Crank slider is a common mechanism.The big difference between calculation results and actual results will be showed under high frequency condition without considering the mass of components and friction of bearing.The current calculation method cannot guide design with high accuracy.Based on the research of slider crank mechanism from ‘High frequency single link chain wear test rig' project,the research try to build the dynamic model and thermodynamic model with considering the mass of components and friction from bearing.Major research includes the following aspects:Based on the consideration of the mass of components and the friction of the bearing,the motion law and the force of the moving parts has been researched,and the dynamic model of the model is established.Joint bearing friction power was calculated with the compared following four condition: without considering the mass of components and bearing friction,considering only the mass of components,only considering the bearing friction,and considering both mass of components and bearing friction.The calculation results show that,in the case of high frequency,whether or not to consider the mass of components and bearing friction impact on the calculation results significantly.The temperature field calculation model of joint bearing is established.The friction power of the joint bearing is obtained by using the dynamic calculation under 20 Hz.Temperature calculation nodes arranged on the inner ring of the joint bearing,the outer ring,the roller way,the end face,the bearing housing and the drive shaft.The heat transfer network is transformed into a circuit model by using the RC thermal simulation method.The software MathCAD is used to calculate the heat transfer network.After calculating the thermal conductivity and thermal resistance at each point of the object,the corresponding temperature difference is calculated,and the temperature distribution of each point can be obtained.The coefficient correction test has been designed to test the temperature of the nodes under 20 Hz.The convective heat transfer coefficient of the air surface in the thermodynamic model was modified to obtain a more consistent with the actual testing conditions.The accuracy of the model is verified by the experiment.The modified calculation model and the test results are compared and analyzed to verify the accuracy of the calculation model.The experimental results show that the model can effectively simulate the actual working conditions which provides an effective tool for the prediction of the temperature distribution and the optimal design of the test rig.According to the calculation of dynamic and the temperature field,use forced convection to replace the original natural convective conditions,can make the temperature of the bearing reduced effectively which could bring good improvement in order to the bench life and stability.As summary,the research takes the crank slider mechanism as object,based on the consideration of the mass of components and bearing friction,the analysis of the motion law of the moving parts is completed.The dynamic model of the crank slider mechanism and the temperature field model of the joint are established,and the heating and temperature field distribution under the high frequency are calculated.The calculation results and the test results are compared,and the parameters in the model are modified to obtain a more accurate calculation model.The research provides reference method for the development and design of crank slider mechanism in the test rig.