颤振的成因分析与解决对策

Causes analysis and countermeasures of flutter

为了解决因汽车颤振引起驾乘者不舒适感的问题,对汽车起步或换档时产生颤振的成因以及影响因素进行了研究。首先,分析了颤振产生的原因和表征,建立了自诱发振动模型和受力振动模型;然后,对汽车颤振进行了实际测试和仿真,分析了汽车产生自诱发颤振和压力诱发颤振的条件、机理;最后,讨论了各种因素对汽车颤振的影响。研究结果表明:颤振只发生在离合器滑磨阶段,摩擦片负摩擦系数梯度会产生汽车自诱发颤振,发动机绝对转速、离合器从动盘与压盘的转速差、变速箱转速和曲轴轴向振动的变化会产生压力诱发颤振;通过增大摩擦片的摩擦系数梯度、内置一个柔软的波形片、合理限制产品公差、装配中预紧、提高传动系阻尼等可以有效减少汽车颤振,提高汽车的驾乘舒适性,从而为离合器的设计和制造提供改进方向。

In order to solve the problem of discomfort caused by vehicle flutter,the causes and influencing factors of vehicle flutter when starting or shifting were studied.Firstly,the causes and characteristics of flutter were analyzed,and the self-induced vibration model and stress vibration model were established.Then,through the actual test and Simulation of vehicle flutter,the conditions and mechanism of vehicle self-induced flutter and pressure-induced flutter were analyzed.Finally,the effects of various factors on vehicle flutter were discussed.The results show that the flutter occurs only in the clutch sliding stage,the negative friction coefficient gradient of the facing will elicit the vehicle self-induced flutter,and the changes of engine absolute speed,the speed differential between the clutch disc and the pressure plate,the speed of the transmission and crankshaft axial vibrations will lead to the pressure-induced flutter.The vehicle flutter can be effectively reduced by increasing the friction coefficient gradient of the facing,building in a softer cushion,logically restricting the product tolerances,pre-tightening components in assembly and increasing the damping in the drive train,to improve the driving and riding comfort of the vehicle.Which provides the improvement direction for the design and manufacture of the clutch.