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ID:57046557
大小:999.50 KB
页数:26页
时间:2020-07-28
《尺寸链计算方法课件.ppt》由会员上传分享,免费在线阅读,更多相关内容在教育资源-天天文库。
1、StackuptolerancesSummary:StackuptolerancesusefulnessTraditionalcalculationQuadraticandprobabilisticmethodStackuptolerancescalculationsheetDFSStoolsStackuptolerancesusefulnessAnyphysicalparthassomevariationsinitsdimensions,whatevertheproductionprocessutilized.The3Dpartshownonthecomputerscreen
2、willinfactneverphysicallyexist.Thecadmodelshowsonlythetheoreticalnominalofthedesign.Therealpartwillbealwaysdifferent.Thestudyoftheimpactthedimensiontoleranceshaveonthedesign’smainfunctionsisintegrallypartoftheengineeringdesignactivity.Lateornostackupduringthedesignphasecandrivetocompleteconc
3、eptredesignandortoolscrap/modification.Tolerancemanagementisakeythinginmechanicalengineering.IntroductionThetheoreticalpartTherealpartTraditionalstackupNominalvalue:bTolerance:tb==QuadraticmethodtX4、ble.Itisnotrecommendtousethismethodforkeysafetydimensions>XNominal+1/2Probabilisticmethod>Examplea=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Workingconditions:weneedafreeplay,Xmustbebiggerthanzero.AretheproposedtolerancesanddimensionsOK?Proposeddimensionsandtolerancestobecheck5、edNominalvalue:bTolerance:tbExample.Traditionalstackupa=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareNOK.Nominalvalue:bTolerance:tb==Traditionalstackup113-110-(7/2)=-0,5Xminiisnegativesothereisthepossibilitytohaveaninter6、ference.a=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareOK.Thetolerancecanevenbelarger.Nominalvalue:bTolerance:tbXminiispositivesowehavealwaysafreeplay.XNominal-1/2Xmini=113-110-(/2)=1,59QuadraticmethodExample.Quadraticme7、thod.a=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareOK.Nominalvalue:bTolerance:tbXminiispositivesowehavealwaysafreeplay.Probabilisticmethod>Xmini=XNominal-113-110-(/2)=0,49Exam
4、ble.Itisnotrecommendtousethismethodforkeysafetydimensions>XNominal+1/2Probabilisticmethod>Examplea=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Workingconditions:weneedafreeplay,Xmustbebiggerthanzero.AretheproposedtolerancesanddimensionsOK?Proposeddimensionsandtolerancestobecheck
5、edNominalvalue:bTolerance:tbExample.Traditionalstackupa=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareNOK.Nominalvalue:bTolerance:tb==Traditionalstackup113-110-(7/2)=-0,5Xminiisnegativesothereisthepossibilitytohaveaninter
6、ference.a=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareOK.Thetolerancecanevenbelarger.Nominalvalue:bTolerance:tbXminiispositivesowehavealwaysafreeplay.XNominal-1/2Xmini=113-110-(/2)=1,59QuadraticmethodExample.Quadraticme
7、thod.a=113+/-1b=20+/-0,5c=40+/-0,5d=10+/-0,5e=20+/-0,5f=20+/-0,5Conclusion(preliminary)TheproposedtolerancesanddimensionsareOK.Nominalvalue:bTolerance:tbXminiispositivesowehavealwaysafreeplay.Probabilisticmethod>Xmini=XNominal-113-110-(/2)=0,49Exam
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