轮胎不规则磨耗机理-测试-改良.ppt
Confidential,轮胎不规则磨耗机理/测试/改良,欧阳博二九年五月廿五日,Confidential,内容提纲,简介1983 北美 All-Season PCR 轮胎之不规则磨耗问题不规则磨耗机理之分析如何应对和改进不规则磨耗问题试验室高效测试法之思考,Confidential,简介不规则磨耗之种类不规则磨耗之可能原因,Confidential,不规则磨耗之种类,Alternate Lug WearBoth Shoulder WearBrake Skid/Flat Spot Wear,Spotty WearCupping/Scallop WearDiagonal Wear,Confidential,不规则磨耗之种类,Erosion/River/Channel WearFeather Edge Wear,Shoulder Step/Chamfer WearOne-Sided Wear,Confidential,不规则磨耗之种类,Rib Punch WearShoulder Scrubbing/Scuffing Wear,Heel&Toe Wear,Confidential,不规则磨耗之可能原因,悬挂系统问题设计维护轮胎使用与维护充气压不当不当使用刹车，转弯过猛超载胎压不足,Confidential,不规则磨耗之可能原因,轮胎设计和制造质量问题胎面花纹设计花纹块弱/不稳定胎面胶不耐磨，过软胎体胎冠设计胎体或带束刚性不足轮胎制造质量均匀性不良,Confidential,1983 北美 All-Season PCR 轮胎之不规则磨耗问题非驱动轮胎(undriven tires)二/四 行花纹严重 Heel&Toe WearAll-Season 胎用块状花纹多为高速公路之磨耗，条件相对温和,Confidential,1983 Uniroyal 调查结果,Confidential,Ludwig,G.S.and Brenner,F.C.,Distribution of Speed and Acceleration on a Treadwear Course,Tire Science and Technology,v.9,Nos,1-4,1981,典型子午胎耐磨性路試時，橫向及縱向加速度分佈圖,橫向,縱向,Confidential,进一步观察驱动轮胎:OSS 胎面有 Shoulder Wear其余磨耗轻微，且均匀非驱动轮胎:OSS 胎面有 Shoulder Wear二/四 行花纹严重 Heel&Toe Wear,Confidential,前轮驱动 后轮驱动前轮 后轮 前轮 后轮磨耗率快 较慢 快 较慢磨耗均匀 不均匀不均匀 均匀驱动 制动 转弯 自由滚动,高速公路轮胎不规则磨耗分析,Confidential,此类不规则磨耗不能归之于轮胎转弯此类不规则磨耗之轮胎大部分时间处于自由滚动状态，且其他为制动与转弯，而无驱动。,高速公路轮胎不规则磨耗分析,Confidential,不规则磨耗机理之分析,Confidential,Schallamach Pattern 的形成是從連續打滑來的,Confidential,正常的子午胎的胎面上很難找到 Schallamach patterns,Confidential,斜交胎与子午胎耐磨性之比較,斜交 子午哩程（千英哩）12+48-60+束帶無有應力大小打滑大，連續性小，間歇性Schallamach patterns有，多無，少,Confidential,胎面膠摩耗之机理第一步：疲勞老化(Mechano-thermo-chemical degradation)第二步：斷裂分离 卷离法(Roll formation)脫皮法(Delamination or spalling),Confidential,Confidential,1 mm,Concrete Cement and Sand,Tread rubber,Tread rubber,Confidential,Confidential,Roll Formation Process,Confidential,自由滚动时 Heel&Toe Wear 之考虑,Confidential,轮胎自由滚动之应力变化,Contact PressureSymmetric,Longitudinal ShearAnti-symmetric,p-t-p shear,Confidential,制动时轮胎之应力变化,Contact Pressure Skewed forward,Additional negative longitudinal Shear,Resultant shear,p-t-p shear,Confidential,驱动时轮胎之应力变化,Contact pressure skewed backward,Additional positive longitudinal shear,p-t-p shear,Confidential,制动 自由滚动 驱动,Peak to Peak 前后剪切应力变化幅度之比较,疲劳老化速度之不同,Confidential,從刮痕看胎面打滑度与輪胎側滑角之關係（0 度到 1 度）,Confidential,從刮痕看胎面打滑度与輪胎側滑角之關係（2 度到 3 度）,Confidential,驱动,制动,從刮痕看胎面打滑度与輪胎驱动，制动之比较,Confidential,因此，胎面胶皮层之应变能是自由滚动时高于一般驱动状态。而块状花纹的应力-应变以及其离开地面接触时的形变，可影响其接地滑移现象，其行为概述如下:,高速公路轮胎不规则磨耗分析,Confidential,轮胎印痕比较,Prone to 2/4 row irregular wear,Confidential,滚动半径(rolling radius)之定义-普通定义-点定义法,Confidential,What is Radius?,Websters Dictionary:A line segment between the center of a circle and any point on its circumference.,Circumferential Length=Radius*2p,Confidential,What is the rolling radius for a deformed circle?,Conventional Definition:Rolling Radius=Distance per rotation/2p,For 1.000 mile N Rolling Radius,Confidential,滚动半径的点定义,R=DL/Dq=(XO XO)/(qB qA),Confidential,滚动半径与步跨,(XB XA)=(XD-XC)+SA+SB,Confidential,What control the free rolling radius?,DeflectionTread gaugeLateral grooveBelt lengthEdge vs.centerNylon capInflation pressure,Confidential,如何量自由滚动半径差？,Confidential,Split Drum,L1,L2,L3,L4,L5,L1 L2 L3 L4 L5,Confidential,Split Planks,Confidential,Rolling radii mismatch and row wear,Confidential,The Twin-Tire Test Method,Not identical twin-Rolling radii mismatch about 2.5%.,Confidential,The Twin-Tire Test Method-continued,Confidential,制動与驱動之比較：刮痕/大小輪法測試後胎面形態,Confidential,总结,All-Season 轮胎块状花纹在 2/4 行之 H/T 不规则磨耗，主要是由于：非驱动轮胎胎面胶皮层之疲劳老化在自由滚动状态下，高于驱动轮胎。第 2/4 行花纹之自由滚动半径略小，造成较高的制动状态，不利于 H&T 偏磨耗。第 2/4 行之滚动半径之略小，与印痕形状相关，即所谓M-ness 或 W-ness,Confidential,总结,减少轮胎花纹行与行之间的自由滚动半径差，当有利于降低不规则磨耗。胎冠带束层及 cap ply 设计优化块状花纹，沟及 sipes 之设计优化小心控制双轮法中大小轮胎之自由滚动半径差，此法可能成为实验室对不规则磨耗的快速筛选试验法。,Confidential,MTS 860 Tire Indoor Wear Test Machine,Confidential,提高胎面膠耐磨性之方法,減緩胎面膠疲勞老化之速度用低滯後性膠料減少發熱以降低溫度填充料-用量，比表面積，結構，表面化學橡膠-低玻璃溫度,Tg油-品種，用量熱導率降低溫度防老劑耐老化橡膠提高膠料抗斷裂強度提高膠料之滯後性以抗斷裂填充料-用量，比表面積，結構，表面化學橡膠 MW,MWD,支化度,Confidential,谢谢,Confidential,Confidential,Confidential,Tire Treadwear Mechanisms,Treadwear is a fatigue failure processDegradation:Mechano-thermo-chemical Rubber removal:FractureRoll formation of degraded skin rubberDelamination.Wear rate(Frictional energy)NN=1No slippage during degradation stageN 1Multiple stick-slip Tread skin brush model,*The“Frictional energy”as defined by Grosch should be called the total bulk strain energy.,Confidential,Tire Treadwear Mechanisms-conti.,Question:In an indoor wheel test,how would a tire wear?Safety-walk Talc powder Tread surface conditions.no wear,oily,humps formed wear,oily,gummy(very slow wear,dry lubricated)*wear,dry or less oily*Just a guess,never performed.,Confidential,Tire Treadwear Mechanisms-conti.,Road surface textureA necessity:Smooth 67”wheel tests do not wearSkin rubber with stress concentration points.Local slippage takes place when contact points exceed the stick thresholddegree of multiple stick-slip depends on stress levels as well as the conditions on both surfaces,namely,that of the tread skin and the road.,Confidential,Tire Treadwear Mechanisms-conti.,Road DustAlso a necessity in treadwear under dry conditions:for the roll formation processThe amount of dust needed is probably not more than the amount of rubber removedToo much dust could become dry lubricant,affecting the wear rate.,Confidential,Confidential,Treadwear Prediction,Develop tread skin brush model for more accurate determination of the”frictional energy”The model assume the skin rubber degradation is directly related to the amount of heat dissipatedDetermine the criteria for single cycle and multi-cycle,then compute the amount of heat generated and absorbed by the skin rubber,Confidential,
