Dynamic Analysis And Optimization Of Vibration Isolation System Of A Refrigerator Compressor

Fully enclosed reciprocating compressor is the core component of refrigerator,and also an important research object in the design of refrigerator vibration and noise reduction.This paper aiming at the engineering research of vibration isolation design and structure optimization of refrigerator compressor,the dynamic characteristics of refrigerator compressor vibration system are analyzed by theoretical modeling calculation and vibration modal test,and the parameters of the system force transfer rate are optimized,which provides a reference for the design of vibration and noise reduction of compressor.First of all,according to the structure and working principle of refrigerator compressor,the compressor is simplified as a dynamic model of 3-DOF two-layer vibration isolation system,the vibration differential equation is established by Lagrange equation.The three order natural frequency of the compressor isolation system is calculated by using the mathematical software MATLAB,it is 3.4236Hz,14.7469Hz and 63.5231 Hz,respectively.The expression of force transfer rate of compressor system is derived.The curve of force transfer rate is plotted,and the influence of various parameters on force transfer rate is analyzed.Secondly,in order to improve the effectiveness of optimal design and avoid blindness of optimization,the sensitivity analysis of the parameters in the formula of force transfer rate is carried out.The sensitivity parameters:support spacing,eccentricity,damping and shell mass are selected as optimization variables,with the minimum force transfer rate at the working frequency as the optimization objective function,the optimization mathematical model is established and the genetic algorithm in the MATLAB optimization toolbox is used to optimize the calculation.The third order peak value of the force transfer rate curve is reduced by 0.7 dB,0.5dB and 1.1 dB,respectively,which provides a reference for the optimal design of the refrigerator compressor.Thirdly,dynamic characteristic analysis of refrigerator compressor whole machine and pump body by using finite element software ANSYS Workbench.The natural frequency of the first three steps is low,and the vibration modes is the whole vibration form;and the second three order modes are shown as the vibration form of the internal exhaust pipe.The first four natural frequencies are in the frequency range of 50 Hz,so we should pay special attention to the occurrence of resonance;And after the fifth order,the natural frequency higher.Finally,vibration and test system LMS Test.Lab is used to test the compressor by hammering method.Compared with the natural frequency of finite element analysis,the minimum error is 1.18%of the first order and the maximum error is 5.65%of the 5th order.The corresponding theoretical calculation of the third-order natural frequencies is 3.502Hz,14.263Hz and 61.354Hz,respectively,and the error is 2.24%,3.39%and 3.54%,respectively,the accuracy of the finite element simulation and the reliability of the mechanical model are explained within the allowable range.