Research On The Suspension Rubber Bushings' Influence On Vehicle Riding Comfort

With outstanding characteristics of convenience, little space occupation and so on, vehicles play an important role in the transportation field of passengers and freight transport, as well as the area of our daily life. Meanwhile, the quality requirements for vehicle riding comfort of the majority car users are also getting higher and higher. Because of rubber bushings superior high elasticity, the internal architecture of rubber material will produce friction damping when deformation occurs, which also can effectively attenuate the external excitation passing to the rubber vibration. Therefore, rubber bushings have become necessary automotive element for modern cars. Besides, the rubber bushing is used as an important load-carrying structure part in suspension system. At present, both the domestic and foreign research for the automobile suspension vibration isolation performance mainly focus on the aspects of positioning parameters of suspension system, steering mechanism, spring and damping elements and so on, while the study on automobile riding quality of suspension rubber bushings are relatively rare. So the study of rubber bushings on vehicle riding comfort has become an important research field in suspension system.Firstly, based on automobile ride comfort research theory, automobile vibration system's random road excitation model of time domain and frequency domain under the conditions of uniform motion and accelerated motion and the Kelvin-Voigt model of rubber bushing simplified model were introduced respectively. Combined with common rubber bushing simplified model that does not take into account and consider the simplified model of rubber bushing model 8-DOF semi physical model of the car were established and then using the Lagrangian method established two kinds of mathematical models respectively, for simulation research in subsequent chapters.Secondly, under the conditions of constant speed and acceleration, combined with the established road random excitation model and two kinds of 8-DOF half vehicle mathematical model, this paper from two aspects of time domain and frequency domain, simulated and analyzed the variation of vehicle vibration system output when considering and not considering the suspension rubber bushing. The influence of rubber bushing on automobile ride comfort were analyzed with the simulation results. The simulation results show that the time domain and frequency domain simulation results of the system are reduced to a certain extent when the rubber bushing is added to the suspension system. It shows that the rubber bushing of suspension has a better inhibitory effect on the vibration of the vehicle and can improve the ride comfort of the vehicle.Finally, this paper from time-domain and frequency-domain, rubber bushing stiffness and damping effect on the response of variation system were simulated and analyzed, when car vibration system were in constant condition and accelerating condition. Conclusions can be obtained by analysis, when rubber bushing stiffness values increase, it has a greater influence on vibration system response of time domain and frequency domain. When rubber bushing stiffness value changes from quarter of the original rubber bushing stiffness value to 5 times of the original rubber bushing stiffness values, the amount of time and frequency response of the system increases, and close to coincide with system response that did not consider the rubber bushing. When rubber bushings damping value changes from quarter of the original rubber bushings damping to 5 times of the original rubber bushings damping values, response value of the system in time and frequency domain do not change obviously.Conclusions can be obtained by above analysis, to adapt to vehicles smooth and comfortable ride requirements under various conditions, in the selection of suspension system rubber bushings parameter values, rubber bushing stiffness values should be matched within the range of 0.5 to 4 times of the original rubber bushing stiffness value. Rubber bushings damping nearly have no impact on system response, so it can be ignored when matching rubber component parameters.