The Measurement Technology Of Air-Floating Impeller Dynamic Balance Under Non-Stationary Rotating Speed

The turbocharger for the car is a gas-driven rotary machine that can provide more power to the car.But it cannot avoid vibration during operation.The impeller rotor is a key component of the turbocharger and has high precision for the single rotor of the impeller.Dynamic balance is an important means to ensure reliable and high-speed operation of the entire equipment.Therefore,it is of great significance to study the dynamic balance of air-floating impeller rotor.In this paper,the impeller rotor in the turbocharger of the vehicle is taken as the research object.Based on the vibration rotor mechanics analysis and the working principle of the static pressure gas bearing,the impeller rotor dynamic balance test platform and measurement of the vertical air bearing hydrostatic bearing are designed.Based on the influence of factors such as the fluctuation of the speed of the air-floating impeller rotor on the measurement accuracy,the filtering of the dynamic balance vibration signal of the impeller rotor,the extraction of the vibration signal at the non-stationary speed,and the filtering of the half-speed eddy interference signal are analyzed.In addition to the influence coefficient method with restrictions on the weight of the weight and the amount of residual vibration.The main research contents and innovations of this thesis are as follows:1.For the filtering problem of high-noise vibration signals,the relationship between the singular value of the approximation signal and the number of scale spaces is fitted by polynomial curve,and the fitting error is minimized,and the number of scale spaces is automatically determined to improve the multi-resolution singular value decomposition algorithm.The filtering effect of common methods.2.For speed instability caused by gas floating stability problems and possible gas bearing half speed vortex interference problems,analysis of the local mean decomposition(local mean decomposition,LMD)algorithm,and select from LMD autocorrelation method of sliding step length,and root mean square and kurtosis value to determine the LMD filter condition and calibration using singular value decomposition(PF(the Product Function,PF)component of the three aspects to improve and get higher precision under non-stationary speed of vibration signal.3.When the top surface of the impeller rotor is used as the correction surface,the machining difficulty is high.According to the actual situation,the impeller rotor is divided into two dynamic balance modes of single-sided double measuring point and double-sided double measuring point,in limiting the weight and residual vibration.Under the limited condition,the simulated annealing algorithm with stronger local search ability is used to improve the influence coefficient method based on genetic algorithm,and the calibration result with higher balance efficiency and smaller error is obtained.The non-stationary speed of the air-floating impeller rotor dynamic balance measurement system designed in this paper is more in line with the impeller working environment.The rate of primary unbalance reduction is over 95%,the balance quality error is within 0.05 g,and the phase error is within 8°.The problem of unbalance measurement of air-floating impeller rotor at working speed is solved,and the balance effect is good.