Soft Body Dynamics Analysis And Modificationresearch Of Transmission Helical Gear

Gears are important parts of the automotive transmission. Which are related to the stable and reliable operation of the vehicle. Lower the gear vibration and noise during operation has become one of the research emphases in the transmission gear research.In this paper, a dynamic analysis about the noise and vibration in unload and full load condition match to the forth gear of Xiali 2000 car has been studied. Through the multi-target gear modification, reducing its noise and vibration during operation.According to the design requirements, establish a geometric model of the fourth gear by the KISSsoft, and a modal analysis has been finished to obtain the resonance frequency and the mode shapes response of each modal frequency. generated the modal neutral files with the stress and strain of each gear.A flexible body dynamic model of the transmission fourth gear helical gear has been established in ADAMS, and verified the accuracy of the model. Through the result of the loading analysis, the reason of the gear vibration and noise is tooth frequency and the multiply frequency. In order to explore the impact of the gear shaft, a gear model with shaft was set up, and as show in the analysis result, the deformation of gear shaft deterioration of the working conditions of the gear, and add the shaft frequency to the gear vibration characteristics of the gear. By optimize the shaft diameter and the supporting position of the shaft, the impact of the gear shaft deformation can be reduced.Analysis the factors affecting transmission helical gear tapped, and establish the excitation function to simulation the torsional vibration fluctuation of the engine. Using ADAMS to simulate the tap process, the main reason for the rattling noise is torsional vibration of the engine Through change the torque, moment of inertia and the angular acceleration, the rattling force can be changed. Multi-target modification to the fourth gear by the KISSsoft, compare the change of stress distribution and transmission error, then analysis the modification impact on improving the working conditions of the gear. Analysis the load condition and the unload condition of the gear after modification, the modification method not only make the gears run more smoothly, but also ensure the rattling force didn’t change significantly. The result achieved the purpose of optimize.