Structural Optimization On Variable Wrap Height Scroll Compressor For Automotive Air Conditioning

Based on the consideration of small size and light weight,the current scroll compressor has a small number of scroll circle results in a relatively low internal pressure.During the summer operation,the phenomenon of exhaust under compression is likely to occur,resulting in a decrease in the isentropic efficiency of the compressor.By changing the wrap height of the scroll plates,the internal volume ratio of the variable wrap height scroll compressor is increased,and the internal pressure ratio is increased.In order to improve the operating life of scroll compressor with variable wrap height,the thermal stress analysis and fatigue life analysis of the scroll plate under the coupling of temperature and pressure fields were performed by the finite element method,and the parameters of scroll wrap height were optimized according to the distribution of equivalent stress.The specific research contents are as follows:(1)The geometric theory of the variable wrap height scroll compressor is analyzed,and the volume and gas pressure of each compression chamber are calculated,which provides a theoretical basis for the subsequent thermal stress analysis.(2)Establish the solid model of the orbiting scroll,which was imported into the finite element software to generate the finite element model.The stress and deformation analysis under the coupling of temperature load and gas pressure load were carried out.The simulation results show that the stress concentration phenomenon occurs at the root of the scroll wrap and the stress value is large.The maximum equivalent stress occurs near the root step and the maximum deformation occurs at the top of the wrap head.(3)According to the thermal stress analysis results,the high parameters of the scroll wrap were optimized,and the maximum equivalent stress of the optimized orbiting scroll was reduced by 8.52%.Using the nominal stress method,according to the S-N curve of the scroll material and the load spectrum under the national standard test conditions,the fatigue life of the optimized movable scroll was analyzed.The analysis shows that the minimum life position of the orbiting scroll is the location where the maximum equivalent stress occurs,and the fatigue life of the orbiting scroll after optimization can reach 393.25 hours.(4)A prototype of a variable wrap height scroll compressor was developed for refrigeration performance experiments,lifetime experiments and noise monitoring.Ex-perimental results show that the variable wrap height scroll compressor can meet the requirements of relevant national standards through structural optimization.