载荷与径向刚度对机械弹性车轮包容特性的影响

为解决机械弹性车轮在不平路面的冲击振动传递问题,提高车辆行驶平顺性能,该文基于弹性滚子接触模型、有限元分析及试验测试方法对车轮的包容特性及影响因素进行了研究。通过对车轮有效路形的分析,揭示了负荷和径向刚度对车轮包容特性的影响规律,并验证了所建模型的可靠性,结果表明:在车轮径向刚度一定的条件下,有效路形幅值随负荷的增加而减小,但有效路形扰动长度随负荷的增加而增大;在负荷一定的条件下,有效路形幅值随车轮径向刚度的增加而增大,扰动长度随之增加而降低。利用有限元模型和台架试验对车轮的低速稳态包容特性进行了分析,得出了车轮垂向动态力学响应随负荷和径向刚度变化的规律,在径向刚度一定的条件下,车轮垂向力响应随负荷的增加由抛物线形过渡到马鞍形,在负荷一定的条件下,车轮垂向力响应随径向刚度的增加而增大,分析结果反映了该车轮实际包容特性的客观规律性。该研究为机械弹性车轮结构优化及整车振动特性分析提供了参考。

Influences of loading and radial stiffness on mechanical elastic wheel enveloping characteristics

To change the situation of the existing tire, developing runflat and antipuncture tire to guarantee high performance and security has become a consensus of the world''s major tire manufacturers.Therefore, researchers have recently focused their attention on nonpneumatic tires with different structures.But the nonpneumatic tires have the disadvantage of excessive weight, complex processing technology or cooling difficult and so on.Furthermore, the process of manufacturing such tire is still in the stage of research and development.To solve the above problems, a mechanical elastic wheel (MEW) for the offroad vehicle is proposed which is a kind of nonpneumatic tire.The MEW could be realized the basic function of traditional pneumatic tire.In additional, the problems such as stinging, puncturing and blasting damage can be avoided.Thus, the MEW is greatly satisfied with requirements of safe service for the special vehicles, such as military vehicles, offroad vehicles, emergency service and disaster relief vehicle.In this paper, to solve the shock vibration transmission and improve vehicle ride performance when the MEW is running over uneven road, we studied the enveloping characteristics and influencing factors of MEW using the flexible roller contact (FRC) model and the method of the finite element simulation and experiments.The influence of loading and radial stiffness on the enveloping characteristics of the MEW was revealed according to the analysis of the effective road input.Moreover, the reliability of the model was verified.The amplitude of effective road input of MEW decreased with the increase of loading, and the disturbance length increased with the increase of loading.Under this circumstance, the radial stiffness was unchanged.And the amplitude of effective road input of MEW increased with the increase of radial stiffness, but the disturbance length decreased with the increase of radial stiffness under a certain loading.The analytical solution, finite element simulation and experimental results were in excellent agreement for the effective road input.The MEW swallowed the cleat completely when the obstacle was centred under the hub centre, and it behaved as if there were no cleat at all under a certain loading.The results indicated that the MEW had the remarkable characteristics of enveloping cleat, reducing the impact and prolonging the action time when the MEW was running over uneven road.Based on the established finite element model and the bench testing, the enveloping characteristics while traversing the obstacle at low speed was investigated, and the influence of loading and radial stiffness on the vertical dynamic mechanical response were illustrated.The vertical dynamic mechanical response of MEW increased with the increase of radial stiffness under a certain loading.In the lowdeflection case, the vertical force curves were similar to a parabola.With increasing deflection, in the medium deflection case, there were two maximums and between them a minimum occurred, the trend was called camel back.The MEW swallowed the cleat completely under a certain loading, which could be called typical static enveloping characteristics.The analysis results reflected the objective law of the actual enveloping characteristics of the MEW, and provided a reference for the MEW structure optimization and the vibration characteristics of the whole vehicle.