| Manually operational gearbox (for short, gearbox) is one of the important transmission components for many medium and heavy duty automobiles, its dynamic activities and work performance affects greatly the whole vehicle's capability. Many facts show that the noise of gearbox is one of the main sources of the automobiles' noise. With the people's requirement for more comfort of riding, vibration decreasing and noise absorption have been an important task of automobile industry. Therefore, study on the reasons that result in the gearbox's vibration and noise, furthermore bringing forward an optimizing design for gearbox has some academic and practical value.In this paper, the main factors that bring the gearbox's vibration and noise are theoretically studied, three kinds of exciting force which effect gear's vibration are analyzed, two forms of gearbox's noise and its transmitting routes have been discussed. According to the drawings, the 3D model of SGI 35 gearbox assembly was established under the PRO/E environment, and the dynamics analysis of gearbox's housing was carried out using the finite analysis software of I-DEAS, then the dynamics parameters (inherent frequency and inherent vibration styles) of gearbox's housing are obtained basing on the results of FEA, the experiment for measuring vibration and noise of different position on gearbox housing surface was designed. Totally ten of SGI35 gearboxes have been tested under different work conditions. The frequency and spectrum analysis, demodulation analysis was applied to analyze the testing signals. In this way, the vibration and noise charactics of the gearbox at different speed are analyzed. The reason which causing the vibration and noise was found out and the methods for controlling the vibration and noise are designed.In addition, a software for testing and analysis of vibration and noise of automobile gearbox was developed in Visual C++ Measurement Studio. The software was applied to the work of this paper. |
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