Analysis And Improvement Of Cab NVH For A Excavator

Excavator has a widely use in engineering. The NVH performance of cab not only affects the driver efficiency and safety, but also related to the life of components.So the NVH of Excavator has received increasing attention. This top uses noise and vibration testing techniques,multi-body dynamics,and FEM to analysis and improved design the NVH performance of a excavator. The main research contents include:(1)Testing and initially diagnosing for the whole NVH of prototype. By engine vibration test, engine and cab mounting system performance test, cab noise and vibration level test, then analysis and processing of the data, initially diagnose the cause of high level in cab noise and vibration. By doing these, provide guides for the further CAE analysis.(2) CAE analysis for noise and vibration performance. By analyzing the key components which produce and transfer the cab idle noise and vibration, determined the cause of NVH problem in cab.The specific work is as follows:Analyze the noise and vibration performance for cab.First of all,create the finite element model of the cab and calculate its structural modal,initially analyzed the low-frequency dynamic characteristics.Then, establish two FEM model of the cab sound field which have seat and without seat, and calculate the acoustics mode analysis of the two models.Comparing the results, the resonance possibility in idle was excluded and the seat affect on acoustic modal was analyzed.Finally, harmonic response analysis was carried out, and by using the result of it for boundary conditions, the panel contribution for cab noise was calculated.So the panel with significant contribution to cab noise was identified.Analyze the cab mounting system performance.Establish the six degrees of freedom rigid body model for cab mounting system, and calculate the rigid body modes and the energy distribution.Finally Judge the vibration isolation performance of cab mounting.Analyze the vibration performance of rotating platform.Create the FEM model and calculate the modal, analyze its affects for the NVH problem of this topic.(3)With the problems revealed in the test and CAE analyze, optimize and improve the cab structure, cab mounting system and rotation platform.Propose the noise and vibration reduction measures and verity the improvement effect by test or CAE.This topic has the follow innovation point:The domestic cab NVH research for construction machinery is still rare.This topic carried out a comprehensive research in vibration transfer and noise-vibration relationship for a excavator, enriched the content of this aspects in some degree, so it has certain reference innovation.