Study On Crankshaft Strength And Structure Optimization Of Scroll Compressor Drive System

Scroll compressor has the advantages of simple structure,small volume,energy saving and high efficiency,etc.It has been widely used in refrigeration and air conditioning,various gas compression,fuel cell and other fields.Vortex compressor is mainly composed of dynamic and static vortex disk,crankshaft,frame,main bearing,balance iron and anti-rotation mechanism parts,such as the interaction between components,the core component failure or defects design can directly or indirectly affect the machine running stability and reliability,led to a decline in scroll compressor performance.Therefore,the reliability of core components is the key to ensure the efficiency of the whole machine,and the optimization of components is the premise to ensure the performance and safety of scroll compressor.Based on the actual working condition of scroll compressor,this paper summarizes the common driving system fault factors,establishes the fault tree of scroll compressor driving system,and makes qualitative analysis to identify the weak links of the system.On this basis,it is established that the crankshaft strength problem and the vibration problem under the critical speed are the key points to ensure the operating stability of the transmission system.A type of scroll compressor drive system in a university as the research object,first in view of the transmission system of the crankshaft strength problems,combining with the basic theory of the transmission system,using the finite element software statics analysis was carried out on the transmission system of the crankshaft,checking its strength,many times at the same time discussed the structure parameters,the material,the finite element simulation the influence of the load on crankshaft strength,fatigue analysis of crankshaft finite element results provide data.In the long-term working process,the crankshaft strength problem is easy to cause high cycle fatigue damage,which will have a serious impact on the running stability of the compressor,so it is necessary to predict the fatigue life of the crankshaft when the crankshaft strength meets the design requirements.Based on the simulation software nCode DesignLife,the five block diagrams of fatigue life analysis were established to analyze the fatigue characteristics,and finally the cloud diagram of crankshaft fatigue life and the earliest fatigue failure area were obtained.The results show that the fatigue life of crankshaft is long,which provides the analytical method and theoretical guidance for transmission system design and fatigue analysis.Completed for crankshaft strength problem above intensity and fatigue life prediction of the crankshaft,then in view of the critical speed of the vibration problem of the transmission system structure is optimized,the purpose is to improve the transmission system of first order natural frequency,enhance its ability to resist vibration,based on the modal analysis of finite element analysis software Ansys Workbench under the Environment of the Design Explorer module of transmission system for the response surface analysis and the multi-objective optimization,optimization results show that the transmission system of first order natural frequency to improve quality at the same time is reduced,After optimization,the stability and economy of the transmission system are realized.Based on the fault tree of scroll compressor drive system,this paper analyzes two main factors that cause system failure: crankshaft strength problem and vibration phenomenon.On the two main factors,on the one hand,completed the crankshaft strength checking,and analyzes the multiple factors that affect the intensity of crankshaft,provides reference for improving the strength of the crankshaft,at the same time meet the design requirements in strength long time work under the premise of considering the fatigue characteristics of completed the crankshaft fatigue life prediction,provide analysis method for the research on fatigue characteristics.On the other hand,the crankshaft structure of the transmission system is optimized to improve the first order natural frequency,reduce the occurrence of vibration,and improve its stability.