Dynamics Analysis And Experimental Research On Transmission Gear Rattle

The nature of rattle phenomenon is due to speed fluctuation of the drive gear in the gear pair, speed fluctuation result in repeated impact as contact and detach appear alternately. As the advanced studies of the transmission NVH, study of the vibration and noise has already been mature. The rattle phenomenon caused by unload gear pair have been highlighted, and resulted in more and more attention. Meanwhile transmission rattle noise is a transient noise, the noise level will have a significant jump phenomenon, and to the human ear tend to be more sensitive to changes in amplitude. This paper focuses on the mechanism of transmission rattle phenomenon and propagation path, researches for both the theoretical simulation analysis and practical test analysis, and establishes the connection.①As the gear backlash reflected in kinetic equation is strong nonlinear, the dynamic response performance is typical nonlinear system, so the gear system study belongs to nonlinear kinetic dynamics field. Aiming at excitation from gear impact, the paper studies dynamic characteristics of gear rattle formed by the gear backlash. Starting with single gear pair rattle, established nonlinear torsional vibration dynamics model using lumped parameter method, considering the gear backlash, drag torque and load fluctuations. Investigated rattle dynamic characteristics under the influence of multi-parameter.②On the basis of analyzing the gear pair, establish the rattle transmission system dynamics simulation model. In this paper, the magnitude of external incentives and drag torque are the two parameters which we are researching for. At the same time it introduces the concept of rattle index, which is used to evaluate the strength of rattle.③on the basis of theoretical research, building rattle test bench, the experimental platform is based on analog excitation in real working condition of automobile transmission rattle phenomenon as the prerequisite. Design combined with the function of the hardware and software testing, test mainly depends on the B&K software rattle real-time measurement of transmission, include frequency spectrum, time spectrum and order characteristics of transmission, and combined with the simulation analysis. B&K software through different angles to proceeding the transmission signal acquisition and analysis on the rattle phenomenon at the same time, including the measurement of vibration signal analysis, noise analysis and sound pressure level measurement analysis.④We are taking a transmission as the research object, establish simulation model, analyses its character, at the same time testing on the bench experiment. This experiment is mainly the comparative experiments of different excitation amplitude and different drag torque contrast experiment. Through the simulation analysis and testing of the transmission, rattle characteristics of transmission were studied. At the same time introduce the concept of sound pressure level, and rattle index were compared. As evaluation standards reflect the strength of transmission rattle.