Analysis and optimization of abnormal noise at low speed of a truck transmission

Abstract

Aiming at the abnormal noise during idle driving of a commercial vehicle, an approach combining testing and simulation was adopted to study its manifestation and optimization solutions. First, vibration and noise tests were conducted, confirming that the abnormal noise was gear rattle. Then, a one-dimensional dynamic simulation model was established. Using rattle energy as the evaluation index for transmission rattle intensity, the influence of relevant parameters was analyzed. The pre-damper stiffness and hysteresis, primary damper hysteresis and preload force were found to have the most significant impact on rattle intensity. Finally, simulation analysis was used to predict the improvement effects of the optimization solutions. Two optimization measures—increasing the pre-damper stiffness and reducing the primary damper preload force—both demonstrated significant improvements, with the rattle indicators decreasing by 52.2% and 58.9%. Validation results showed that the amplitude of the housing vibration signal significantly decreased and no rattle noise was perceived inside the vehicle. Both solutions effectively resolved the issue. The analysis and optimization methods presented in this study provide a valuable reference for addressing other similar gear rattle problems.