Study On The Rattle Vibration Characteristics Of DCT Power Transmission System Under Internal And External Excitation

With the increasing demand for car comfort by drivers and passengers,the NVH(Noise,Vibration and Harshness)quality of cars has attracted the attention of many scholars at home and abroad.Among them,the transmission gear rattle phenomenon has obvious broadband noise characteristics and noise level jump phenomenon,which is easy to cause driver discomfort and is one of the most important noise sources in automobile power transmission systems.In recent years,due to the advantages of smooth and smooth shifting,economical fuel saving,and high transmission efficiency,dual-clutch transmissions have sprung up in passenger car products equipped with dual-clutch transmissions and the main problem of gear rattle noise appears.This article takes a certain automobile power transmission system equipped with dual-clutch transmission as the research object,and uses the method of combining numerical analysis and simulation experiments to study the inherent characteristics and knocking vibration characteristics of the power transmission system.Finally,the sensitivity analysis of the tapping intensity using different parameters provides a basis for further optimization.The main research contents of this article are as follows:(1)Considering the time-varying meshing stiffness,backlash,tooth surface transmission error and other non-linear excitation factors,the dynamic modeling of the single-stage load-bearing gear pair and non-load-bearing gear pair inside the transmission are carried out.The generating conditions of the internal gear knocking phenomenon of the dual-clutch transmission are analyzed,and the blocking torques are classified and calculated according to the different stress conditions of different gear pairs in the dual-clutch transmission.(2)Based on the centralized parameter method,a 32-degree-of-freedom DCT power including the engine harmonic torque model,the dual-mass flywheel model,the transmission gear drive system model including the load gear and the non-load gear,the load model,and the equivalent model of the vehicle inertia is established Percussion vibration model of transmission system.(3)Based on the system rattling vibration model,the inherent characteristics of the DCT power transmission system were studied.Through Matlab simulation calculations,the natural frequency,natural mode,vibration mode,modal energy distribution and parameter sensitivity of the system under the first gear driving conditions are analyzed.(4)The MATLAB/simulink engineering software was used to simulate and analyze the established model,and the root mean square value of the gear meshing power was used as the evaluation index of the knocking strength.The regularity of the influence of the structural parameters on the knock strength of the transmission.(5)Based on the method of orthogonal test design,for the four key factors that affect the gear rattle vibration during the first gear,an orthogonal table with four factors and five levels is used to obtain the optimal level of the minimum knocking strength under the comprehensive influencing factors.Combination,and the significant order in which the four factors affect the knock.According to the experimental results,an optimization plan was formulated,and the optimized gear rattle vibration phenomenon was effectively suppressed.