Noise Analysis And Optimization Research Of Wheel Loader Gearbox

In recent years,the export demand for domestic loader products has been increasing,but due to poor vibration and noise levels,their noise level has become one of the key factors affecting their exports.As a key component of the transmission system of loaders,the gearbox has become one of the important noise sources of loaders due to its high speed and heavy load applications.In this paper,the noise of a wheel loader gearbox was tested and analyzed to identify the main noise sources of the gearbox.Noise reduction technology was studied from the noise sources to improve the noise level and comfort of the gearbox,as well as to improve the overall quality level and competitiveness of the gearbox.This paper refers to a lot of foreign and domestic engineering machinery,gearbox,gear noise reduction and gear modification related information and literature.Based on prototype testing,model simulation,and theoretical calculation,a convenient,fast and practical noise identification and reduction scheme for loader gearbox was proposed.Firstly,a wheel loader was tested according to the national standard noise testing process to obtain noise test data and corresponding spectrum.Through spectrum analysis,combined with the working principle of the gearbox and the power transmission path of the gear pair,it was confirmed that the main noise sources of the gearbox were the input gear set,the gear pump input gear set,and the gear pump.Next,in-depth analysis and research on the identified noise sources was conducted to identify the key reasons for their impact on noise.The main reason for the input gear set and the gear pump input gear set is that the gears are not designed for modification.Secondly,based on the actual situation of the noise testing condition of the loader,a simplified gearbox model was created through the ROMAX software,and the load spectrum,hydraulic cycle condition and forward 1st gear condition were set.Static analysis was conducted on the gearbox input gear set and gear pump gear set,and dynamic analysis was conducted on the transmission error,meshing misalignment,contact pattern,and unit length load,to confirm that the gear set has significant transmission error,bias load and other issues,which provides the basis for gear modification.Thirdly,through the ROMAX software,the gearbox noise gear set was respectively subjected to tooth profile modification,tooth alignment modification,and comprehensive tooth profile and tooth alignment modification.By comparing the changes in transmission error,contact pattern and unit length load of the gear set before and after the modification,it was concluded that the comprehensive tooth profile and tooth alignment modification is the best modification scheme.Finally,based on the principle of resonator noise reduction,the noise reduction schemes and effects of the Helmholtz resonator were studied.The side branch resonator with the best side branch length on the gear pump and the Helmholtz resonator with the best design parameters were found which provides an effective solution for the noise reduction of the gear pump.In summary,the noise reduction effect was verified through the identification and cause analysis of the noise sources in the gearbox of wheel loaders,the simulation analysis and modification optimization design of noise gear sets based on ROMAX,the resonator design of the gearbox gear pump based on the resonator principle,and the application of noise reduction schemes.Finally,combined with noise testing experiments,it has verified its noise reduction effect.This provides a certain practicable solution and reference for similar products to reduce vibration and noise.