| Vehicle’s NVH performance is greatly affected by vibration isolation property of powertrain mounting system(PMS). Vibration isolation performance directly decides vehicle’s driving stability and safety which are basic requirement for engineering vehicles. Reasonable design of PMS can significantly isolate engine vibration caused by engine disturbances, improve the vehicle driving stability and safety, and prolong the service life of engine and mounts. The frequency and decoupling ratio of a loader’s PMS, which is the research object of this paper, are optimized in order to improve its isolation performance. Researching works in this paper mainly include:1. Vibration excitation of PMS is investigated and the 6DOF dynamic model of PMS is built, after which the PMS’s design theorys that are layout of decoupling and energy method of decoupling is analysed.2. The optimal mathematic model is proposed according to energy decoupling theory, and the mount stiffness and position are selected as design variables in Matlab programming. The results show that optimal frequencies are more rational, and the optimal decoupling ratios in Z and θx directions are increased significantly.3. Calculate frequency responses of optimal scheme using ADAMS to analyze its validity and feasibility. Then MCS method is used in Isight to study optimal scheme’s reliability. Based on reliability optimization theory, and the design variables and inertia properties of the powertrain are described with normally distributed random variables. Then a reliability optimization method is presented and applied based on deterministic scheme. Optimization results show that the reliabilities of the decoupling layout and frequency allocation are effectively improved compared with the deterministic one.4. The sample mount of optimal scheme is mounted in a loader for testing its vibration isolation performance. Experimental results show that vibration isolation performance of the powertrain mounting system is effectively improved. |
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