汽车轮胎用橡胶材料的开发动向

近几年，汽车轮胎用橡胶材料的开发动向一是降低旋转阻力并兼顾安全性；二是提高车辆在冰上行驶的安全性。文章通过分析，阐明了降低旋转阻力并兼顾行驶安全性的理论依据，指出具备该性能的橡胶材料可通过使橡胶的微观结构最佳化，分子量的分布峰值化及加入与碳进行变性反应的填充剂等方法进行开发，并对冰上行驶轮胎用橡胶材料的开发状况进行了综述。     

Q&A读编往来

<正>关键词:轮胎颜色Q轮胎为什么只有黑色的?为什么不像车身一样有各种各样的颜色?A轮胎的主要材质是橡胶,橡胶本来并不是黑色的,而是白色的,事实上世界上第一条轮胎就是白色的。现在绝大多数轮胎呈黑色是由于在橡胶中掺了约30%的碳黑,加入碳黑以后,可以增大轮胎的强度,提高耐磨性能,延长使用寿命,于是黑色就成了绝大多数轮胎的选择。当然,在技术层面上,完全可以将轮胎的颜色弄得五彩斑斓,米其林就开发了世界上第一条彩色     

基于复杂花纹的子午线轮胎径向刚度特性仿真

基于MSC.Marc非线性有限元分析软件,建立了具有复杂胎面花纹的175/65R14型子午线轮胎三维有限元模型.利用Rebar单元模型模拟橡胶-帘线复合材料,采用Yeoh模型模拟超弹性橡胶材料,仿真分析轮胎从轮辋安装、充气到施加垂向载荷全过程的情况,得到轮胎在不同胎压下的径向刚度特性.通过与试验结果的对比,验证了仿真分析的正确性.     

载重子午轮胎与路面相互作用的分析

根据全钢载重子午线轮胎12.00R20的实际结构,考虑轮胎的几何非线性、材料非线性、接触非线性以及大变形等力学特性,应用有限元的方法建立轮胎的三维模型,橡胶材料采用Yeoh模型,橡胶-帘线复合材料采用加强筋模型,并通过轮胎径向刚度的测试验证了模型的有效性.在数值模拟中分析了轮胎在一定充气压力时,在不同垂直载荷和牵引速度的作用下,与地面在接触区域的变形情况、应力分布、摩擦应力分布等滚动接触规律.结果表明,轮胎与地面接触应力分布存在明显的非均匀性,轮胎的接地面积和地面总反力随着滚动速度的升高而增大.     

子午线轮胎静态接触三维非线性有限元分析

采用三维实体单元对195／60R14规格子午线轮胎进行了三维非线性有限元分析，考虑了轮胎的几何非线性、材料非线性、橡胶-帘线复合材料的各向异性、轮胎与轮毂过盈配合以及轮胎接触非线性，给出了轮胎与地面接触过程中轮胎的变形情况、接触区形状变化、接触压力分布、载荷-变形关系等结果，对轮胎的设计和改进具有一定的指导意义。     

橡胶集料混凝土路面耐磨性能应用研究

结合道路混凝土应具备的主要性能,对橡胶集料混凝土的耐磨性能进行了试验研究。在此基础上,得出橡胶集料的不同掺量对橡胶集料混凝土路面强度和耐磨性能的影响关系,探索橡胶集料混凝土路面结构形式及施工工艺,为橡胶集料混凝土路面的推广应用提供理论支持。     

橡胶性能对子午线轮胎胎圈性能影响的有限元分析

采用ABAQUS软件巾的子模型技术,建立了子午线轮胎的三维精细网格有限元分析模型,并对模型进行了有效性验证.利用该模型对轮胎胎圈部危险区域进行了三维精细网格有限元分析,在不改变轮胎结构的前提下,通过调整胎圈部危险区域的橡胶材料力学特性.分析了在充气和静负荷状态下不同橡胶材料对胎圈部危险区域力学性能的影响.分析结果表明,增加子口胶、胎体层胶的定伸长模量和减小圈垫胶的定伸长模量可改善子口包布反包末端性能.     

基于径向刚度法的车辆翻新轮胎使用寿命判定

为了有效判定车辆翻新轮胎的剩余使用寿命，需要科学确定废旧轮胎胎体橡胶老化程度对翻新轮胎使用寿命的影响。在分析废旧轮胎胎体橡胶老化规律的基础上，通过橡胶老化试验测试及回归分析，确定了胎体弹性模量随着橡胶老化年限增加近似线性增大的影响规律；结合计算机仿真技术及试验测试技术，基于轮胎径向刚度法提出了翻新轮胎剩余使用寿命不安全系数计算方法，其计算数值大小与翻新轮胎径向刚度和新轮胎径向刚度之差成正比，与新轮胎径向刚度值成反比；构建了由橡胶加速老化系统、弹性模量测取系统、承载-变形计算机模拟系统和承载-变形测试系统等组成的翻新轮胎剩余使用寿命判定系统；基于径向刚度法和判定系统提出了车辆翻新轮胎剩余使用寿命判定规则，确定了翻新轮胎胎体剩余使用寿命判定具体流程；根据剩余使用寿命不安全系数计算方法和判定规则，将翻新轮胎确定为可正常使用、需降速使用和需报废处理3个级别，并利用11.00R22.5载重车辆翻新轮胎进行了剩余使用寿命判定与评价，依据判定规则分别计算了不同使用年限3条翻新轮胎的剩余使用寿命不安全系数，确定出3条翻新轮胎所对应的级别，判定与评价结论与实际使用情况相吻合。研究结果表明：废旧轮胎胎体橡胶老化程度对翻新轮胎剩余使用寿命影响显著，翻新轮胎径向刚度与剩余使用寿命之间存在较大影响关系；废旧轮胎胎体橡胶老化程度越严重和径向刚度越大，翻新轮胎的剩余使用寿命将会越短。     

稀土对30CrMnSiA钢离子S—N—C共渗组织和耐磨性能的影响

本文研究了稀土元素对离子硫、氮、碳共渗层金相组织，渗层深度及耐磨性能的影响。结果表明，一定量的稀土元素对离子硫、氮、碳工艺具有较明显的催渗作用，使渗层深度提高２５％以上，改善了表面组织，使表面硬度增强，耐磨性能提高２倍以上。     

轿车悬架橡胶衬套结构特点分析

介绍了橡胶衬套的种类,阐述了汽车悬架橡胶衬套的基本性能及其应用情况.研究了悬架的副车架橡胶衬套和控制臂橡胶衬套在车辆中各向特性参数的分布及其对汽车操纵稳定性和平顺性的影响,并对橡胶衬套的结构设计特点、橡胶材料和配方、疲劳破坏性能等进行了分析.     

胎面轮廓形状优化技术研究--提高轮胎耐磨耗性能

胎面轮廓形状对轮胎的耐磨耗性能影响很大，因此对其进行优化很有意义。针对胎面轮廓形状比较复杂的特点，文中采用多个变量来定义胎面轮廓。同时，在现有磨耗理论的基础上，通过对胎面轮廓形状的优化初步给出了评价轮胎耐磨耗性能的指标。在此基础上，采用自编的多目标优化程序对胎面轮廓进行优化，并将计算结果与原胎数据进行了比较，结果表明，不论是从胎面的磨耗速度还是从胎面磨耗的均匀性来说优化胎都要优于原始。     

Optimal tyre usage for a Formula One car

Variations in track temperature, surface conditions and layout have led tyre manufacturers to produce a range of rubber compounds for race events. Each compound has unique friction and durability characteristics. Efficient tyre management over a full race distance is a crucial component of a competitive race strategy. A minimum lap time optimal control calculation and a thermodynamic tyre wear model are used to establish optimal tyre warming and tyre usage strategies. Lap time sensitivities demonstrate that relatively small changes in control strategy can lead to significant reductions in the associated wear metrics. The illustrated methodology shows how vehicle setup parameters can be optimised for minimum tyre usage.     

Influence of temperature on the tyre rolling resistance

Temperature is a very important factor controlling rolling resistance of road vehicle tyres. There are at least three different temperatures that may be considered as important factors controlling thermal conditions of the rolling tyre. The most common measure of the thermal conditions during tyre rolling is ambient air temperature. The other two are: pavement temperature and “tyre” temperature. Tyre temperature is the most difficult to establish, as temperatures of different parts of rolling tyres differ considerably, thus there is a problem to obtain representative values. In the authors’ opinion, air temperature is the most universal and reliable parameter to measure. The article presents results obtained in the Technical University of Gdańsk during laboratory and road measurements of different car tyres rolling on different pavements. The knowledge of rolling resistance characteristics is important for modelling car dynamics as well as fuel consumption. It is also necessary to establish proper test conditions in the future standardized on-road method of measuring rolling resistance. The results indicate that generally each tyre and pavement combination is influenced by the air temperature in a unique way, but at the same it is possible to propose some general influence factors that may be used to normalize measurements to the standard temperature of 25 °C.     

Laboratory alignment procedure for improving reproducibility of tyre wet grip measurement

Since 2012, the Korean and EU governments have been running a tyre labelling system. All tyres sold in Korea have to carry a label that displays information of two performance criteria: rolling resistance and wet grip. The rolling resistance of the tyres determines their fuel efficiency grading, and the wet grip of the tyres determines their braking safety grading. The rolling resistance and wet grip measurements must be reproducible, so the same tests on the same tyres in different laboratories must produce the same results to ensure a fair comparison between tyres from different suppliers. In addition, a good reproducibility of testing results prevents market surveillance authorities from obtaining results different from those provided by suppliers when testing the same tyres. The laboratory alignment procedure for the rolling resistance measurements was developed and published as the EU Commission Regulation No. 1235 in 2011. However, the laboratory alignment procedure for the wet grip measurements has not yet been developed. Therefore, there are many differences in the wet grip test results among test laboratories throughout the world. The new procedure that is proposed for the wet grip measurement alignment for tyre testing laboratories can improve the reproducibility of the wet grip testing results, and five laboratory alignment tests were carried out between KATECH and five other test laboratories in the world to evaluate the results of the proposed procedure.     

Identification of the mechanical properties of bicycle tyres for modelling of bicycle dynamics

Advanced simulation of the stability and handling properties of bicycles requires detailed road–tyre contact models. In order to develop these models, in this study, four bicycle tyres are tested by means of a rotating disc machine with the aim of measuring the components of tyre forces and torques that influence the safety and handling of bicycles. The effect of inflation pressure and tyre load is analysed. The measured properties of bicycle tyres are compared with those of motorcycle tyres.     

轮胎制动与驱动特性的理论模型

轮胎印迹内垂直载荷的分布与形式的选择，对建立轮胎制动与驱动特性的理论模型有很大影响。根据轮胎制动和驱动时印迹内垂直载荷分布特性，以及轮胎的前后变形特性，建立了轮胎制动、驱动特性的理论模型。应用该理论模型的计算结果，与试验结果具有很好的一致性。     

抗滑水轮胎技术的新发展

轮胎在湿路面上的行驶性能关系到汽车的安全性。阐述了国外开发的三种新型抗滑水轿车轮胎的设计思想，结构特点以及主要性能，介绍了提高轮胎在潮湿带水路面上行驶性能的新技术及其新发展，对开发国产高性能轿车轮肥具有现实的参考借鉴意义。     

车轮荷载下土壤静力学特性分析

利用有限元软件ANSYS建立三维有限元模型,模拟车轮和土壤的静态接触,进行非线性有限元分析,研究车轮荷载下土壤的静力学特性。采用基于Drucker-Prager的弹塑性模型来模拟真实土壤,并考虑摩擦作用。分别采用刚性轮模型和超弹性轮胎模型模拟车轮,并将2种情况进行对比。结果表明：在车轮荷载作用下,土壤的竖向位移和等效应力在轮胎与土壤接触的区域最大;土壤的竖向位移和等效应力随土壤深度的增加而减小;土体在刚性轮作用下的变形和应力要远大于其在超弹性轮作用下的值,表明虽然刚性轮几何形状简单,模型设置容易,但是与超弹性轮胎模型相比,这种模拟精确度低。     

A thermo-frictional tyre model including the effect of flash temperature

A new tyre model is developed that can predict the influence of both macroscopic and local flash temperature on tyre force generation. The model comprises two heat-transfer solvers. A macroscopic solver calculates the 3D temperature distribution across the tread and sidewall at a resolution of a few millimetres. A separate flash-temperature solver calculates the local hot-spot temperature distribution at the macro-asperity tyre-road contact interface at a resolution of micrometres. The two heat-transfer solvers are coupled with a structural model for the calculation of tyre forces and the sliding speed distribution along the contact patch. The sliding speed distribution feeds into the flash-temperature model and the local coefficient of friction is found as a function of sliding speed, flash temperature, normal pressure, road roughness and the complex modulus of rubber. The proposed tyre model is the first to include the effect of a changing macroscopic temperature distribution on the build-up of the local flash temperature, and to account for road-tread conduction at the macro-asperity contact interface. The model is applicable for identifying the friction envelope and optimum temperature range for tyres on roads with known roughness. This is important in motorsport where knowledge of grip offers a competitive advantage.     

轮胎径向尺寸对加速行驶车外噪声的影响

为了准确获取轮胎径向尺寸变化对加速行驶车外噪声试验的影响,文章采用同一辆乘用车换装2种型号轮胎,依据GB1495—2002《汽车加速行驶车外噪声限值及测量方法》进行对比试验。结果显示,轮胎径向尺寸变化会对加速行驶车外噪声试验结果产生影响,并指出采用径向尺寸较小的轮胎,加速行驶车外噪声试验过程中汽车发动机转速越高,噪声试验最终结果也越大。文章建议将轮胎尺寸的差异列为车型判定的条件。