| With the rapid development of our country’s economy,the demand for cars is increasing,and consumers are increasingly demanding cars.The car must not only have good driving performance,but also require better appearance quality.To obtain high-quality car bodies,coating equipment with higher performance is required.In the field of body coating,the spraying of the rotary cup electrostatic atomizer is the most commonly used coating process.It has the advantages of stable performance,energy saving and environmental protection,uniform coating,so it is widely used in automatic spraying technology.Most of the rotary cup electrostatic atomizers are driven by a pneumatic turbine.The core component of the turbine is a static pressure air bearing,which has the advantages of high rotation accuracy,good stability,cleanliness and environmental protection.The key factor that determines the spray quality of the atomizer is the rotation speed of the turbine.At a higher rotation speed,the thickness of the coating film will be thinner and the coverage effect will be more uniform.The current atomizer rotation speed used in China is usually 30000～45000rpm.If a higher speed is used,the atomizer will experience greater vibration,severe noise and unstable operation,so the quality of spraying cannot be guaranteed.In response to the above problems,this paper takes the static pressure air bearing as the core,which directly affects the stability of the pneumatic turbine.innovatively optimizes a new set of static pressure air bearing-rotor system,and through the vibration test,it is proved The optimized scheme is feasible,and the optimized rotary cup atomizer can run smoothly at the speed of rotation,and the scheme has been used in actual products..The main research content consists of the following aspects:1.Through the gas lubrication theory,derive the NS equation,the state equation,the continuity equation and the general Reynolds equation,establish the pressure gas film mathematical calculation model of the static pressure air bearing,and carry out the finite element analysis on this model.Calculate the bearing capacity and stiffness of the bearing.2.Use the three-dimensional modeling software UG to build a model of the threedimensional watershed of the pressure air film,and use the FLUENT fluid finite element analysis software in ANSYS Workbench to analyze the static pressure air bearing.The static pressure air bearing radial bearing and The static characteristics of the thrust bearing and the influence of different structural parameters on the bearing capacity and stiffness of the bearing were explored,and the optimal bearing structural parameters were selected.3.According to the gas lubrication theory,the theoretical derivation of the dynamic pressure effect is carried out,and the influence of the dynamic pressure effect on the bearing capacity and stiffness of the static pressure air-floating radial bearing is analyzed and studied using FLUENT software,and it is verified that the optimization under the dynamic pressure effect Whether the bearing capacity and rigidity meet the design requirements.4.Establish a three-dimensional model of the optimized pneumatic turbine bearing-rotor system,and perform modal analysis and harmonious response analysis on it,obtain the loworder natural frequency and mode shape of the system,and calculate its critical speed according to the natural frequency;then pass Harmonic response analysis is carried out on the bearingrotor system applying an external load,and the vibration velocity response changes of the bearing installation position under different frequency external loads are studied.The optimized atomizer was tested experimentally,and the rationality of the optimized scheme was verified by studying whether the vibration speed at different rotation speeds was within a reasonable range. |
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