鍵、花鍵KeypointsofthischapterRolesofkeys,splinesandpinsintheconnectionofshaftsandhubs鍵、花鍵、銷在軸轂聯(lián)接中的作用Typesofkeysandtheirfeatures(類型與特點(diǎn))Failureandstrengthcalculationofstraightkeyjoint

平鍵聯(lián)接的失效形式與強(qiáng)度計(jì)算Typesandapplicationofsplinejoints1.Rolesintheconnectionofshaftsandhubs

plsdefineordescribe:Hub輪轂:SmallgroupdiscussionbenefitsthestudentsShaft軸:Whykeys?(i.e.theroleofkeyjoint)topreventrelativeangularand/oraxialmovementbetweenhubandshaft周向固定軸向固定toguiderotatingelementsontheshaftslidingaxially旋轉(zhuǎn)零件沿軸向滑動totransmittorqueandpowerfromashafttoahub,orviceversa傳遞軸轂間扭矩和動力2.Typesofkeysandtheirfeatures

Keysarestandardized;machinedesignersneedtoselectproperkeysforthedesignwork.ClassificationofkeysStraightkeys*Woodruffkeys*Taperkeys*Square-endedRound-endedRound+squareGuided

keysPlain

flatkeysFeather

keysFeaturesofstraightkeysCrosssection:squareorrectangleLoadtransmittedbythesidefaceWorkingfaces工作平面:twosidesClearance

availableNoeccentricity:Location:easyforassemblingKeyway(鍵槽)

intheshaft:finger-anddisk-shapedmillingcuttersKeywayinthehub:throughhole(通孔)

forgoodassembling

slotting(插削)orbroaching(拉削)Accordingtohowtheyareused,straightkeysareclassifiedintoPlainflatkeys普通平鍵Guidedkeys導(dǎo)向平鍵Featherkeys滑鍵ClassificationofstraightkeysPlainflatkeysUsedfortransmittingtorqueonlyAccordingtotheshapesofkeyends:RealobjectsRoundendsSquare+roundSquareendsKeywaycutwithafinger-shapedcutterGoodfitandpositioningGreaterstressatthekeywayendofshaftKeywaycutwithadisk-shapedcutterScrewsneededforgoodfixingStressatthekeywayendofshaftreducedUsedattheendofshaftGuidedkeysUsedasaguidewaywhenthehubmovingalongtheshaftaxis

當(dāng)輪轂在軸線方向上移動時(shí)，用于導(dǎo)向Features:Preventrelativerotationofmatingparts防止相配合零件的相對轉(zhuǎn)動Enablehubtomoveaxiallyovershaft使零件可在軸上作軸向移動Keyissecuredonshaft;shortaxialmovementSeemotionpictureFeatherkeysUsedasaguidewaywhenthehubmovingalongtheshaftaxisFeatures:PreventrelativerotationofmatingpartsEnablehubtomoveaxiallyovershaftKeyissecuredintothehub;largeraxialmovement

FeaturesofWoodruffkeys

半圓鍵的特點(diǎn)Features:Usedforfixedjoints;transmittingtorqueonly靜聯(lián)接Workingfaces:twosidesKeycanswayinthekeywayoftheshaft

鍵可在軸上的鍵槽中擺動，便于裝配Greaterdepthofkeywayintheshaftweakensthestrengthofshaft

軸槽深度較大，削弱了軸的強(qiáng)度FeaturesofTaperkeys楔鍵的特點(diǎn)Features:Workingfaces:topandbottomUsedfortransmittingtorqueandaxialforceInclinationoftoptobottom1:100

上、下側(cè)面的斜度為1:100Usedforheavy-dutyapplications

用于重載場合Motionpicture:assembly3.Failureandstrengthcalculationofstraightkeyjoints

PossiblefailureofstraightkeyjointsFixedjoints:workingfaceoftheweakerelement(hub)crushed零件的工作面被壓潰Slidingjoints:elements(keywayinshaft/hub+key)wornseverely零件的磨損Keysaresnipped鍵被剪斷Strengthcalculation強(qiáng)度計(jì)算Crushingstrength擠壓強(qiáng)度條件Wearablecapacity耐磨性條件Shearingstrength剪切強(qiáng)度條件SeeyourhandoutsandChinesebookThestepsforselectingstraightkeys鍵的選擇Consultthestandardofkeysaccordingtothediameteroftheshaft;getthesectionsizeofkey(keywidth×keyheight)

ConsultthestandardofkeysaccordingtothewidthBofthewheelhub;selectproperkeylengthLinkeylengthseries.企業(yè)應(yīng)用…Checkthestrengthcalculationofthejointwhennecessary.Ifthestrengthisinadequate,thelengthofkeywillbeproperlyincreased,ordesignandcalculatethekeyagainuntilthestrengthconditionissatisfied.4.Typesandapplicationofsplinejoints

CanberegardedasmultiplekeysthatareintegratedwiththeshaftUsedasfixedjointsbetweenahubandashaft用作軸轂間的靜聯(lián)接Applications:Usedasslidingjoints,e.g.shiftinggear動聯(lián)接,如滑移齒輪Features:Greatercarryingcapacity:largerworkingsurfacesGreaterfatiguestrength:nokeywayintheshaftisneededElementsmountedonshaftareaccuratelycentered

軸上零件的定心性好Classificationandfeatures1)Parallel-sidedspline矩形花鍵MajorandminorcirclesD,dLocatingsurface:minorcircleWorkingsurface:sidefacesHeattreated+grindedUsedinMT+autoindustriesStructureApplications加工簡單，一般用于輕中系統(tǒng)的靜連接2)Involutespline漸開線花鍵Profile:gear-likeStructurePressureangleis30or45Locatingfaces:profileAdvantagesStrongcarryingcapacity:gearLongerservicelife:使用壽命Higherpositioningaccuracy定心精度DisadvantagesHightorque+bigshaft漸開線花鍵，齒上有徑向力。能起到自動定心作用。一般用于扭矩，大直徑軸；汽車變速器中，用漸開線花鍵動聯(lián)接（配用同步器）Seemotionpicture3)Thin-toothinvolutespline細(xì)齒漸開線花鍵StructureSmallertoothApplicationsLight-load輕載Thinwallelement薄壁件Taperaxle:錐形軸端Finger-shapedmilling指狀銑刀Disk-shapedmilling盤狀銑刀Guidedkey導(dǎo)向平鍵聯(lián)接Note:ThekeyissecuredontheshaftTaperkeySplinekeyTechnicaltermsShaft:

along,generallycylindricalbar,especiallyonethatrotatesandtransmitspowerHub:

thecentralpartofawheel,usedtofastenthewheeltoashaft.THANKSFORLISTENINGNewwordsforChapter11DesignofBeltdrivesVersatility多功能性Pulley皮帶輪Mesh嚙合Groove凹槽