文本内容:
Brieflyintroducethebasicknowledgeaboutthedesignofeverypartofamachine.Fromthecourseweshouldknowwhatkindofrequirementweshouldfulfillforexampleweshouldfulfilltherequirementofthestrengthrigiditystabilityandsoon.Nowadayswiththeaimtoreducecostandincreasetheinterchangeabilitymostpartsarealreadystandardizedandserialized.Sothejobleavesyoutodoistofirstestimatethestressorloadonthepartthenchoosetheserializedpartfromthetable(youknowthere9resometablesorlistsinthemthereseverysizeofthepaifsparameterandyoucanchoosethesuitablepartaccordingtothepressureactingonthem)forthirdafterweconfirmthesizeweaccuratelycalculatethestressorforceactingonitandcomparewithitsratedparametertocheckwhetheritisqualified.Ifnotwechooseanotherandcheckitagain.forexampleintheprojectofthiscoursewedesignedagearboxandwhenwechoosetherollingbearingfirstweselectabearingfromthelistaccordingtodiameteroftheshaftthenwecalculatetheequivalentdynamicalload(当量动载荷)andcheckitsbasicrateddynamicalload(基本额定动载荷)fromthelist.Afterthatweusethisfunctiontocalculateitsworkinglife.Andifthisparameterfulfillstherequirementthisbearingisqualified.1寿命公式推导P1932当量动载荷计算P194Ithinkthedesignofthegearisthemostcomplexfistyouneedtoestimateitsteethnumberaccordingtothetransmissionratiothenwecalculatethediameterbasedontherequirementofthegearprofilecontactfatiguestrength(齿面接触疲劳强度),thenweconfirmthemodulus(模数),thegearbreadth(齿宽)andsomeotherparameteratlastweusetherequirementofthebendfatiguestrengthofthegearfoot(齿根弯曲疲劳强度)tocheckthegearifthestrengthlowerthantheratedstrengthitisqualified.Whenwedesigntheshaftfirstwecalculatethetorsionalstrength(扭转强度)toestimatetheminimumdiameter(扭矩强度和弯曲强度公式P171W=sectioncoefficient)afterweconfirmtheminimumdiameterweshoulddesigntheshaftstepbystepaccordingtothestructurethenwecouldmakesurethelengthofeverypartoftheshaftandtheactionpoint(作用点)ofeachpressureselectthedangeroussectioncalculateitsstrengthsuchasthesynthesisbendstrengththesafetycoefficient[SJP174thecriticalrotatingspeed.Thatisawholeprocessofdesigningashaft.Machinerydesign机械设计introducethebasicknowledgeaboutthedesignofeverypartofamachineFromthecourseweshouldknowwhatkindofrequirementweshouldfulfillforexampleweshouldfulfillthestrength(强度)rigidity(冈U度)Nowadaysthemostpartsarealreadystandardizedforreducecostandincreasetheinterchangeability.Sothiscourseteachushowtodesignthepartsthatarestandardized.Forexampleboltsitseverysizearestandardizeditslengthwidthheightbuttheimportantdesignistheradiusbecausetheradiusdecidethestrength.soifwewanttodesigntheradiusofboltswemastfirstknowtheloadthatitholdupandthematerialofbolts.Secondweworkouttherealradiusofbolts.Thenwcfindthestandardradiusthroughthemachinerybook.wormwheeln.蜗轮wormn.蜗杆drive/transmission传动beltdrive带传动chaindrive链传动。