| With the improvement of diesel engine power, the vibration and noise of diesel engine gear transmission system is making more significant contribution to the engine vibration and noise. Grasping the characteristics of the excitation source of diesel engine gear transmission system is the basic foundation to improve the design of diesel engine gear transmission system, further in order to lower the effect of noise and vibration which is the pursuit of modern diesel engine design. The paper studies the vibration characteristic of gear transmission system and engine noise induced by it in detail.Firstly the actual diesel engine gear transmission system is established with solid model and multi-body dynamics analysis model to obtain the meshing force characteristics and gear bearing load characteristics. Based on the model, tooth face friction and contact force parameter of the gear transmission system is considered and study the effect of tooth face friction and contact force parameter on reducing the gear transmission vibration and noise.Then experimental modal analysis of diesel engine is conducted to verify the accuracy of the finite element model of diesel engine. Gear bearing load is applied to the finite element model using harmonic analysis to get the vibration caused by the gear transmission system excitation. The results show that vibration caused by the gear bearing load mainly concentrates in the oil pan and gear cover and clarifies the direction of further reducing diesel engine noise and vibration. On this basis, the study of the gear basic parameters impact on the diesel engine vibration and noise response and different materials of gear cover and oil pan reduce the diesel engine vibration and noise level is carried out.Finally, experimental modal analysis of crank is conducted to verify the accuracy of the finite element model of crank. The multi-body dynamics analysis model of gear transmission and crank and connecting rod mechanism is established. Analyzing kinematic and dynamic characteristics of the rigid-flexible multi-body dynamic model of crank and connecting rod mechanism and studying the effect of crank output speed on gear transmission system working state by multi-body dynamics. |
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