轮毂直驱电动车轮胎刚度及滚阻匹配研究

研究轮毂直驱电动车轮胎垂向刚度与滚阻特性相匹配问题，揭示轮毂直驱电动汽车非簧载质量负效应产生机理，提出利用胎压改变轮胎垂向刚度进而改善悬架特性的方法。设计出四组不同胎压的轮胎垂向刚度试验，并将轮胎实际垂向刚度应用到悬架特性分析上。结果表明，通过调节轮胎垂向刚度改变了悬架特性的二阶共振频率使其远离人体敏感振动频率，并在一定程度上抑制其振动幅值。为解决轮毂直驱电动汽车轮胎刚度与滚阻特性匹配问题，研究胎压对轮胎滚阻特性和能量损耗的影响，并对四组胎压的轮胎进行滚阻特性及滞回特性试验。试验结果表明，胎压对轮胎滚动阻力有很大影响，胎压升高，轮胎滚动阻力系数和能量损耗变小。进一步表明，胎压与轮胎滚阻系数的关系及能量损耗的关系两者之间基本是一致的，揭示了轮胎滚动阻力产生机理。因此，利用胎压调节轮胎垂向刚度抑制了电动汽车非簧载质量负效应，兼顾了胎压对轮胎滚阻及能耗的影响，实现了轮胎垂向刚度与滚阻特性的匹配，为轮胎与悬架的相互作用机理提供了理论依据。

Research on Tire Stiffness and Rolling Resistance Matching of In-wheel-motor Direct Drive Electric Vehicle

The matching of vertical stiffness and rolling resistance characteristics of IEV tire are studied in this paper. The negative effect of suspension characteristics caused by the increasing unsprung mass in the IEV is analysed, and tire inflation pressure is utilized to adjust tire vertical stiffness and further improve suspension characteristic. The experiments of tire vertical stiffness under the four groups inflation pressure are designed and implemented, and the real vertical stiffness of tire under different inflation pressure are applied to analysis the suspension characteristics. The results indicate that the second resonance frequency of suspension characteristics are changed by the tire vertical stiffness, which are far away from the sensitive frequency range of human body and the vibration amplitude reduced within a certain frequency range. In order to achieve the optimal matching of the stiffness and rolling resistance characteristics of IEV tire, the effects of inflation pressure on the tire rolling resistance characteristics and energy consumption are investigated, in which the experiments of the tire rolling resistance and hysteresis characteristics under corresponding inflation pressure are implemented respectively. The test results show that the tire inflation pressure has a great influence on the tire rolling resistance, the higher the tire inflation pressure, the smaller the tire rolling resistance coefficient and energy consumption. The results further show that the relationship between the tire inflation pressure and rolling resistance coefficient have an excellent consistent with the relationship between the tire inflation pressure and energy consumption. Therefore, The negative effects of the increasing unprung mass of IEV is improved through the tire vertical stiffness, in which the effects of the tire inflation pressure on rolling resistance and energy consumption should be considered, and this paper provides a theoretical foundation for the interaction mechanism between tire and suspension of IEV tires.