Prediction of vibration behavior of the case of a promising automatic transmission of a truck based on the method of modal representation of a dynamic system

This study is one of the stages of research work to create a verified mathematical model of a promising automatic transmission of a truck, which should adequately describe its vibroacoustic behavior during operation. The article presents the results of an experimental study and simulation of the vibration behavior of a promising automatic transmission. The conditions for conducting an experimental study and the results of processing experimental data for 1st gear are given, which make it possible to evaluate the change in the spectrum of characteristic points of the case depending on the rotational frequency, the dynamics of changes in vibration accelerations during acceleration and deceleration, determine the orders of vibration with the largest amplitudes, identify sources of disturbance and justify the need to consider vibrations in a wide range of frequencies for vibration forms of similar frequencies. Based on the simulation results, the vibration forms of the case and the magnitude of vibration accelerations at characteristic points were obtained, verification was carried out and reasonable modifications were made to the mathematical model, and satisfactory accuracy was ensured, allowing us to proceed to the final stage of the study - simulation the acoustic response. Based on the results of the research stage, valuable scientific and technical results were obtained - the order spectra with the largest amplitude were determined - the 45th and 90th order for all gears, with the exception of 6th gear, where the 65th order dominates; sources of disturbance have been identified - engagement of the input shaft gear with the power take-off shaft gear of the oil pump (45th order and multiples of it, up to the 5th harmonic), engagement of the input shaft with the intermediate shaft in 6th gear (65th order), determined the reason for the discrepancy between the results obtained experimentally and by simulation.