Research On Stability Of Scroll Compressor Rotor System Considering The Effect Of Clearance

Scroll compressor is a positive displacement compressor with unique operation mode and structure.Compared with other types of compressors,it has many advantages such as high efficiency,small volume,low noise,low vibration and so on.Therefore,it has been widely used in the fields of power engineering,air conditioning and refrigeration,and transportation.The rotor system not only plays a role in transmitting power during the operation of the scroll compressor,but also a necessary guarantee for the normal operation of the compressor.Therefore,the actual operation of the rotor system plays a vital role in the performance of the scroll compressor.Due to manufacturing and assembly errors,material deformation and wear,the joint clearance will inevitably lead to the dynamic imbalance of the scroll compressor.During the operation of the scroll compressor,the contact distortion of the components with the joint clearance will occur.When they contact again,a collision will cause a strong non-linear impact load and cause the damage of the rotating pair and affect the normal transmission of the compressor system load.As a result,the operation stability of the scroll compressor is affected.This paper used a combination of multibody dynamics analysis and finite element analysis to study the dynamic characteristics of a scroll compressor rotor system with joint clearance,which provides a reference for the design,assembly and vibration reduction of a scroll compressor drive system.First,the basic theory of the scroll compressor was used as the starting point,and the rotor system was subjected to a force analysis and a balance equation was established using mathematical methods.Second,the three-dimensional model of the rotor system components was established and assembled to obtain a three-dimensional model of the rotor system.Based on this,the ADAMS software is used to establish the dynamic model of the scroll compressor rotor system with the joint clearance at the assembly position of the crank pin and the drive bearing.The dynamic characteristics of the rotor system under different clearances are obtained through simulation analysis.Further analysis of the dynamic characteristics of the rotor system paves the way.The finite element method is used to analyze the transient response of the rotor system under this excitation with the angular acceleration of the driving bearing as the boundary condition.It is showed that the clearance of the rotating pair has the least influence on the displacement of the crankshaft,the greater impact on speed and angular velocity,and the greatest impact on acceleration and angular acceleration.The contact force between the crankpin and the drive bearing presents a characteristic of high amplitude and low frequency with increasing clearance.The crankshaft stress concentration is mainly manifested at the connection between the crank pin and the crankshaft and the pulley,and the stress at the crank pin is the largest,and the maximum stress occurs at 0.8s.With the increase of the clearance,the stress on the crankshaft gradually increases and the critical speed of the crankshaft system gradually decreases.When the clearance continues to increase,the critical speed of the crankshaft decreases.This trend greatly increases the possibility of resonance of the scroll compressor.Strict control of the clearance and other measures are required to avoid rotor resonance and friction and wear.