简单介绍机械零件基本知识机械设计mechanical design.pdfVIP

Brieflyintroducethebasicknowledgeaboutthedesignofeverypartofamachine.

Fromthecourseweshouldknowwhatkindofrequirementweshouldfulfill,for

exampleweshouldfulfilltherequirementofthestrength,rigidity,stabilityandsoon.

Nowadays,withtheaimtoreducecostandincreasetheinterchangeability,mostparts

arealreadystandardizedandserialized.Sothejobleavesyoutodoistofirst,estimate

thestressorloadonthepart,then,choosetheserializedpartfromthetable(youknow

there’resometablesorlists,inthemthere’severysizeofthepart’sparameterandyou

canchoosethesuitablepartaccordingtothepressureactingonthem,)forthird,after

weconfirmthesize,weaccuratelycalculatethestressorforceactingonitand

comparewithitsratedparameter,tocheckwhetheritisqualified.Ifnot,wechoose

anotherandcheckitagain.

forexampleintheprojectofthiscoursewedesignedagearbox,andwhenwechoose

therollingbearing,firstweselectabearingfromthelistaccordingtodiameterofthe

shaft,thenwecalculatetheequivalentdynamicalload(当量动载荷)andcheckit’s

basicrateddynamicalload（基本额定动载荷）fromthelist.Afterthatweusethis

functiontocalculateitsworkinglife.Andifthisparameterfulfillstherequirement,

thisbearingisqualified.

1推导P1932当量动载荷计算P194

Ithinkthedesignofthegearisthemostcomplex,fistyouneedtoestimateitsteeth

numberaccordingtothetransmissionratio,then,wecalculatethediameterbasedon

therequirementofthegearprofilecontactfatiguestrength(齿面接触疲劳强度),then,

weconfirmthemodulus（模数）,thegearbreadth（齿宽）andsomeotherparameter,at

lastweusetherequirementofthebendfatiguestrengthofthegear

foot（齿根弯曲疲劳强度）tocheckthegear,ifthestrengthlowerthantherated

strength,itisqualified.

Whenwedesigntheshaft,firstwecalculatethetorsionalstrength(扭转强度)to

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