1_1基本拧紧技术

基本拧紧技术Basictighteningtechnique12目的与概要Purpose•掌握以下几个要点，并能与客户就生产中的相关问题进行解释，为客户提供正确的工具和方案作指导•内容Content–螺纹紧固件threadjoint–什么是连接件？joint–扭矩，摩擦力和夹紧力的关系torque,frictionandclampforce–关于扭紧的几个基本概念tighteningconception–抗拉强度和屈服点tensilestressandyield3生产过程中的几种装配方法assembly•焊接•粘接•铆接•用螺丝和螺栓拧紧4哪种装配方法最普遍？Whichoneismostcommon•焊接•粘接•铆接•用螺丝和螺栓拧紧?5使用螺丝和螺栓拧紧！Advantageswithscrewsandbolts!•设计简单Simplicityofdesign•零部件标准化Standardized•装配简单，拆卸方便（可逆）Easyassemblyanddisassembly•效率高Highproductivity•成本低COSTefficient•可控（螺栓张力可控）wellcontrolled!Butwhy?•什么是连接Whatisajoint?•部件Parts•不同的连接Differentjointtypes•不同的负载Differentloads•扭矩、摩擦力和加紧力Torque,frictionandclampforce•连接类型Jointtypes•抗拉强度和屈服点Tensilestressandyieldpoint•螺栓标记Boltmarking•螺栓分级Screwclassifications6基本拧紧技术Basictighteningtechnique连接受到不同的外力Thejointisexposedtodifferentexternalforces7什么是连接Whatisajoint?螺栓Screw螺母Nut连接件Joiningparts这种情况必须避免Thismustbeavoided!8Thethreadcreatestheclampforcethatholdsthejointtogether•Turningthenutorscrewstretchesthescrew•Thestretchingofthescrewclampsthepartstogether•Theclampforceinthejointisthetargetofalltightening910施加的扭矩Theappliedtorqueismeasured夹紧力是我们的目标Clampforceisourtarget夹紧力是我们的目标，但是很难测量，而扭矩很容易测量Clampforceiswhatweaimatbutitisdifficulttobemeasured.Torqueiseasytomeasureandtoapply螺纹紧固件Threadedfasteners-Torque11直接测量夹紧力的方法thewaytomeasureclampforce12为了拧紧螺栓,必须施加力以便拧紧螺母/螺丝Theappliedtorqueismust螺纹副摩擦力Frictioninthethreads夹紧力ClampForce螺栓头摩擦力Screwheadfriction50%10%40%施加100%扭矩，夹紧力的结果AppliedTorque(100%)andresultingClampForce…‘正常情况Normalconditions’扭矩Torque100%1450–40–10规则541rule扭矩100%90%的扭矩用于克服摩擦力产生夹紧力ClampForce10%螺纹副中Frictioninthethreads40%螺栓头下摩擦力Screwheadfriction50%夹紧力取决于扭矩和其他因素-摩擦力Clampingforceisdependentoftorqueandotherfactors–mainlyfriction•Fm=T/(0.16P+(μg*0.58*d2)+((Dkm/2)*μk))螺距Pitch螺纹副Thread螺栓头Head•定义Definitions–Fm=夹紧力clampingforce–P=螺距pitchofthread–μg=螺纹副摩擦系数frictionvalueinthread–d2=螺栓直径diameterbolt–Dkm=螺栓头表面尺寸sizeofsurfacebolt(nut)-head•Dkm=(dw+dh)/2–μk=螺栓头表面摩擦系数fricitionvaluesurfacebolt-head1516改变摩擦力–塑料垫圈frictionchange-plasticwasher40%20%40%40%40%塑料垫圈plasticwasher螺纹副摩擦力Frictioninthethreads夹紧力ClampForce螺栓头摩擦力Screwheadfriction17改变摩擦力–加润滑frictionchange-lubrication螺纹里的润滑lubrication18扭矩和夹紧力的关系torqueandclampforce50%20%30%50%30%螺纹里加润滑lubrication螺纹副摩擦力Frictioninthethreads夹紧力ClampForce螺栓头摩擦力Screwheadfriction19摩擦力减小会导致...frictiondecrease50%20%30%...过拧！Overclampforce20改变摩擦力–生锈的螺栓frictionchange-rustybolt生锈的螺栓rustybolt2150%0%50%50%50%生锈的螺栓rustybolt螺纹副摩擦力Frictioninthethreads夹紧力ClampForce螺栓头摩擦力Screwheadfriction扭矩和夹紧力的关系torqueandclampforce扭矩Torque(Nm)角度Angle(degrees)啮合点Snuglevel硬连接HardJoint拧紧到目标扭矩角度小于30°Tighteninganglebelow30°目标Target30硬连接Hardjoint软连接SoftJoint拧紧到目标扭矩角度小大于720°Tighteningangleabove720°over720软连接Softjoint扭矩Torque(Nm)角度Angle(degrees)啮合点Snuglevel目标TargetRealjoints很少连接是硬连接Veryfewjointsarebelow30°很少连接是软连接Veryfewjointsareabove720°绝大多数是中性连接Mostjointsarebetween30and720°为什么这样定义Whydowehavethesedefinitions?硬连接HardJoint拧紧到目标扭矩角度小于30°Tighteninganglebelow30°软连接SoftJoint拧紧到目标扭矩角度小大于720°Tighteningangleabove720°过拧紧OvershootandMeanshift26Target中间飘移MeanShiftTAngle(φ)过拧紧Overshoot贴合面SnuglevelHardSoft抗拉强度和屈服点Tensilestrengthandyieldpoint强度Stress角度Angulardisplacement失效Failure抗拉强度Tensilestrength屈服点Yieldpoint=%抗拉强度oftensilestrength(弹性区域的终点The‘endpoint’ofelasticrange)螺栓扭紧过程定义Tighteningcycle快速旋进Rundown扭矩Torque角度Angle线性区Elasticarea斜率constantslope寻帽Finding屈服点yieldpointΔTΔα塑变区Plasticzone最终扭紧Final基本定义definition：寻帽Fastenerfinding(Searchsocket)快速旋进Rundown最终扭紧Final线性区Elasticarea.半线性区Semi-elasticarea.塑变区Plasticzone.螺栓标识TheBoltMarkingSystem29ManufacturerFirstfigure=1/100ofmintensilestress(N/mm2)100*8=800N/mm2Secondfigure=relationbetweentensilestressandyield0,8=80%Multiplythetwofigurestogettheyieldpoint800*0,8=640N/mm230生产商Manufacturer第一个数=1/100的最小抗拉强度(N/mm2)tensilestress100×8=800N/mm2第二个数=屈服强度与最小抗拉强度之间的关系Relationshipbetweenyieldpointandtensilestress0.8=80%两数相乘得出屈服应力Yield800×0.8=640N/mm2公制螺纹thread.螺栓标识TheBoltMarkingSystem31螺栓分级ScrewqualityclassificationWithtorqueindications32推荐力矩值Recommendedtorquelevels33螺栓连接的分级jointclassificationCATEGORYASSEMBLYCRITICITYExampleNEEDSSTANDARD标准级失效不影响设备功能THEFAILUREDOESNTAFFECTTHEMACHINEFUNCTIONINGSunroof,plasticprotection1-TOASSUREACORRECTTORQUE2-TOASSURETHATALLSCREWSARETIGHTENEDATCORRECTTORQUECRITICAL重要级失效仅仅影响设备功能THEFAILURECANONLYAFFECTMACHINEFUNCTIONINGGearboxfixture,Enginefixture3-TOASSURETHATTHEJOINTISCORRECT4-TOASSURETHATALLSCREWSARETIGHTENEDANDALLJOINTSARECORRECTSAFETYCRITICAL安全重要级失效可导致人身安全THEFAILURECANAFFECTUSERSAFETYWheel,Brakes5-TOASSURETHATALLSCREWSARETIGHTENEDANDALLJOINTSARECORRECT-TOTRACEERRORSANDSTOREALLRESULTS6-100%GUARANTY34•所需最小的夹紧力必须保证连接件在外力影响下部件仍能结合clampforce•最大夹紧力由螺丝/螺栓尺寸和质量，以及相关拧紧设备的精度决定clampforce•541原则torqueandclampforce扭矩的最大值和最小值torque硬连接30°、中性连接30°~720°、软连接720°连接的硬度与目标扭紧的设定有关。按其失效后所产生的后果不同分为三级：–普通连接–重要连接–安全重要连接螺栓的连接硬度jointhardnessclassification螺栓连接的分级jointhardnessclassification总结SummaryMoreThanProductivity