Bench Testing Evaluate Analysis Of Manual Transmission Gear Rattle

The transmission gear rattle noise is a kind of successive impact noise with broadband effect,which will seriously affect the acoustic comfort of the vehicle when transmitted to the vehicle.However,there is no effective test evaluation method to quantify it.This article takes a manual transmission with gear rattle problem as the research object,the bench test research of transmission gear rattle had been carried out,and the evaluation model of the transmission rattle noise based on Subjective evaluation results was established.The main research contents and conclusions of this paper are as follows:(1)The mechanism of gear rattle in transmission was detail analyzed,and classified the gear rattle according to the form of it.The influence of internal and external excitation on gear rattle was studied.The acquisition and processing methods of speed,vibration and noise signals commonly used in gear rattle test were analyzed.(2)The bench test research of transmission rattle noise was carried out,the near-field noise and housing vibration of transmission was measured in real time under different operating conditions.Through the analysis of time domain and frequency domain,the vibration and near-field noise of the gearbox under various working conditions were analyzed and studied.Which found that an abrupt increase in sound pressure and vibration when the gear rattle occurrence.The conclusion that the structure noise small and the air noise large was obtained by using the coherence analysis technique,which provides a reference for the optimization of the transmission noise.(3)The transmission near-field noise collected during the test were played back,selected and cut off,make 22 noise samples with different rattle degrees.Different subjective evaluation methods were compared and analyzed.The magnitude estimation method was selected to carry out subjective evaluation.Evaluation results passed Spearman correlation coefficient examination,remove the evaluation result that the average correlation coefficient is lower than 0.7,and then subjective evaluation results of each noise sample were calculated.In addition,the physical properties of 7 psychoacoustic and 2 psychoacoustic parameters were studied,and 9 objective evaluation results of 22 samples were obtained by theoretical calculation.(4)By studying the correlation between different psychoacoustic parameters of rattle noise and subjective evaluation results,it is found that the fluctuation strength has a low correlation with the subjective evaluation result,and the Sharpness has a high correlation with the subjective evaluation results.The multiple linear regression method(MLR)and the support vector machine method(SVM)were used to establish the transmission rattle noise evaluation model,and the model was examined and compared to verify the effectiveness of the model,which provides a method reference for the transmission rattle noise bench test evaluation.