内支撑安全轮胎零压工况力学特性

Mechanical characteristics of inserts supporting run-flat tire under zero-pressure conditions

安全轮胎零压力学特性是提升轮胎续驶性能、实现车辆爆胎稳定性控制的基础。为研究内支撑安全轮胎的零压力学特性,通过零压工况负荷特性、侧向力学特性及接地特性试验,研究了不同负荷作用下内支撑安全轮胎的径向刚度、侧向刚度及接地特征参数的变化规律,并与额定胎压工况进行了对比。研究表明内支撑安全轮胎失压后,径向刚度表现为分段近似线性,在负荷小于负荷6 000 N时,其平均径向刚度较额定胎压工况降低了84.76%,在负荷大于拐点负荷时,其平均径向刚度较额定胎压工况增加283.34%;内支撑安全轮胎在无明显侧滑区侧向力与侧向位移近似为线性,零压侧向刚度较额定胎压工况增大9.92%,最大侧向附着力降低24.41%;当负荷达到一定数值时接地印痕面积基本保持不变,在胎肩和胎冠中心区域出现应力集中现象,胎面翘曲严重,接地压力分布均匀性变差。研究结果为掌握零压工况下内支撑安全轮胎的力学特性,进行车辆爆胎稳定性控制提供理论基础和参考。

Mechanical characteristics of run-flat tire under zero-pressure conditions are the basis of improving the driving performance of tire and realizing the stability control of vehicle blowout.Insert supporting run flat tire(ISRFT)is a typical safety tire based on pneumatic tire structure.As this type of safety tire has the advantages of simple structure,convenient disassembly and good zero pressure bearing capacity,it has become a new type of safety tire with great development prospect.With the improvement of vehicle performance,the performance of insert supporting run flat tire is also put forward higher requirements.The traditional insert structure is made of heavy materials such as metal and rubber,which has the problems of heat generation,shoulder cracking and so on.It can not meet the requirements of heavy load,high mobility and long-distance driving.Mechanical characteristics of inserts supporting run-flat tire is investigated in order to improve driving performance under zero pressure.Based on the tests of zero pressure load characteristics,lateral mechanical characteristics and tire grounding characteristics,the law of mechanical characteristics parameters of inserts supporting run-flat tire under different loads was studied.The mechanical characteristics parameters under zero pressure and rated tire pressure were comparatively analyzed.In addition,combined with the damage form of zero pressure driving failure,the mechanical characteristics of tire were analyzed.The results showed that the radial stiffness of the inserts supporting run-flat tire was approximately linear after the pressure loss,and the radial stiffness increased significantly after the insert takes part in the load-bearing.When there was no obvious sideslip,the lateral stiffness increases and the lateral adhesion decreases.When the load reached a certain value,the area of the tire's grounding footprint basically remained unchanged.In the center of shoulder and crown of tire,stress concentration appeared.At this time,the tread warpage was serious,and the uniformity of the ground pressure distribution was poor.When the load was less than 6000 N,the tire mainly depended on the structural load of the sidewall,and its radial stiffness was 84.76%lower than that under the rated tire pressure condition.When the load was more than 6000 N,the tire mainly depended on the insert,and the radial stiffness of the tire increased significantly,which was 283.34%higher than that under the rated tire pressure condition.The lateral stiffness characteristic curve consisted of the zone without obvious side slip,transition zone and obvious slip zone under zero pressure.In the region without obvious side slip,the relationship between lateral force and lateral displacement was approximately linear,while in the region of transition and obvious side slip,it was nonlinear.The average lateral stiffness of the tire without obvious sideslip area was 9.92%higher than that of the tire with rated tire pressure.The warpage of tire tread and the variation of uniformity of ground pressure distribution were more significant than those under rated tire pressure condition.When the load increases to 9800 N,the length,width and area of the grounding footprint remained unchanged.The shoulder on both sides and the crown corresponding to the contact of the insert became the main bearing area of the tire.