拧紧曲线分析Howanalyzethetighteningcurve曲线分析的目的purpose•找出连接的特性-软硬连接•机械设备旋转状态•螺栓连接状态•拧紧不合格的原因•螺栓的受力状态2查看曲线时的标识•Ms—motorstop马达停止•At—anglethreashold角度阈值(角度开始)3最终拧紧Final:扭矩斜率快速下旋Rundown扭矩/角度Torque/AngleT(s)TorqueorAngle最终拧紧Final1.快速下旋Rundown2.最终拧紧Final工件被夹紧PartsclampedΔT/Δθ形成扭矩拧紧过程与曲线分析Tighteningprocessandcurveanalysis连接的特性5机械设备旋转状态6TorqueTimemin.torqueMax.torqueTotalAngleAngleUpperlimitLowerlimitStartingangle机械设备旋转状态8螺栓连接状态--StickSlip的典型扭矩曲线Torquevs.Angle-2000200400600800100012000100200300400500600700Angle[deg]Torque[Nm]Torque这样的曲线合格吗?910StickSlip常见来源•StickSlip常见来源Ingeneral:通常:–工件表面粗糙–螺纹副摩擦系数高–软连接,拧紧过程中发热严重–拧紧速度太高(造成螺栓涂层脱落)Type1:类型1:–某些涂层(如孔密封漆,达克罗,交美特等)–某些一体式带垫片的螺栓–螺栓头材料软Type2:类型2:–高L/D(长度/直径)比的螺栓–长螺纹尤其是软性材料–螺纹摩擦力/螺栓头摩擦力比值太高(包括螺纹半径/螺栓头半径)11StickSlip:工具需要考虑的因素•工具需要避免以下情况:–高速拧紧–多步拧紧–在高扭矩点重新启动–在各步骤间没有扭矩保持/加速度太大–工具的齿轮比太高(工具马达太小,靠齿轮组放大扭矩)–工具反作用力臂刚性不足12如何避免StickSlip?•降低加速度•避免高扭矩启动•步骤间保持扭矩•降低拧紧速度•检查拧紧过程——尤其是引起发热的步骤•降低摩擦系数•加强反作用力臂的刚性(力臂或者延长杆)•使用大尺寸马达和小齿轮比(降低工具内的能量消耗)螺栓连接状态这颗螺栓有没有预拧紧?扭矩突变非常大螺栓连接状态分析螺栓连接状态使用了什么拧紧策略?螺栓受力分析塑性区域弹性区域螺栓受力分析螺栓拧紧到塑性区域BoltstightenedinplasticareaMULTICVILII&EME60-30JTensionTorqueTorqueTensionTorqueratebetween1-2=0,28kN/ºTorqueratebetween3-4=0,015kN/ºTorqueratebetween4-5=0,010kN/ºAt200º:Torque147Nm&Tension=66kNAt400º:Torque151Nm&Tension=69kNAt600º:Torque149Nm&Tension=70kN12345这条是什么曲线?拉伸力曲线--特殊软件合成!!!扭矩曲线?夹紧力曲线?MULTICVILII&EME60-30JTensionTorqueTorqueTensionTorqueratebetween1-2=0,23kN/ºTorqueratebetween3-4=0,025kN/ºTorqueratebetween4-5=0,006kN/ºAt160º(3):Torque128Nm&Tension=55kNAt320º(4):Torque128Nm&Tension=59kNAt480º(5):Torque130Nm&Tension=60kN12345螺栓拧紧到塑性区域Boltstightenedinplasticarea800º&900º拧紧到塑性区域MULTICVILII&EME60-30JCurve800º:oneboltAngle160ºtension58kNAngle320ºtension61kNAngle480ºtension63kNCurve900º:anotherboltAngle160ºtension55kNAngle320ºtension59kNAngle480ºtension60kN拧紧到屈服点之后:负的扭矩斜率这几条曲线的含义?拧紧到屈服点之后:负的扭矩斜率22扭矩拧紧+扭矩斜率监控Torquestrategy+torquerateTorquerateresultson3stepsStillintheelasticareaofthebolt23Torquerateresultson3stepsTighteningovertheelasticareaofthebolt扭矩拧紧+扭矩斜率监控Torquestrategy+torquerate24Torquerateresultson2steps:firstoneandlastoneTighteningovertheelasticareaoftheboltTorquerateTorquerate角度拧紧+扭矩斜率监控Anglestrategy+torquerate25TorquerateresultsonlasttwostepsTighteningovertheelasticareaoftheboltTorquerateTorquerate角度拧紧+扭矩斜率监控Anglestrategy+torquerate26Torquerateresultsonthefirstandlaststep–differentsettingsfortorquerateparametersTorquerateTorquerate螺栓受力的什么区域?角度拧紧+扭矩斜率监控Anglestrategy+torquerate27Torquerateresultsonthefirstandlaststep–differentsettingsfortorquerateparameters角度拧紧+扭矩斜率监控Anglestrategy+torquerate28Torquerateresultsonthefirstandlaststep–differentsettingsfortorquerateparameters角度拧紧+扭矩斜率监控Anglestrategy+torquerate29Torquerateresultsonthefirstandlaststep–differentsettingsfortorquerateparameters角度拧紧+扭矩斜率监控Anglestrategy+torquerateMoreThanProductivity