键和花键的公差与检测.ppt

第6章键和花键的公差与检测,Chapter6Thetolerancesandtestsofkeysandsplines,一、键和花键的作用Thefunctionsofkeysandsplines,键与花键常用于轴与轴上的传动件之间的可拆卸联结:Keysandsplinesareusuallyusedatthedetachableconnectionswhicharebetweenthedrivingmediumsofshaftsandonshafts.1、传递转矩和运动Transmittorquesandmovements.2、当配合件之间要求作轴向移动时，起导向作用Theyplaytheguidingroleswhenitisrequiredtomakeaxialmovementsbetweenmatchingparts.,二、键和花键的分类Theclassificationsofkeysandsplines,键：平键、半圆键、切向键和楔形键联结Keys:flatkeys,woodruffkeys,tangentialkeysandwedgebonds.,花键：矩形花键、渐开线花键和三角形花键联结。Splines:Squaresplines,involutesplinesandtriangularsplineconnections.,三、平键配合的精度设计Theprecisiondesignsofflatkeyfits,包括：尺寸精度设计形位精度设计表面粗糙度的精度设计Including:SizeprecisiondesignsFormandpositiondesignsTheprecisiondesignsofsurfaceroughnesses,Thetypesofkeys,Flatkey,Roundkey,Taperkey,Thelabelofkeys,Suchas:b=18,h=11,L=100roundcommonflatkeyslabelisKeyC18x100GB1096-79,1、尺寸精度设计（1）Sizeprecisiondesign(1),平键联结的基本构成：由键、轴键槽、轮毂键槽构成。在工作时，通过键的侧面与轴槽和轮毂槽的侧面相互接触来传递转矩。Thebasicformsofflatkeyconnection:Itisformedbykey,keywayandwheelhub.wheninworking,ittransmitstorquesthroughthemutualcontactbetweenthesidefaceofkeyandthesidefaceofwheelhub.,配合尺寸：键和轴槽、轮毂槽的宽度尺寸。Fitdimensions:Thewidthdimensionsofkeys,axialtroughsandwheelhubs非配合尺寸：如键高、键长、轴槽深、轮毂槽深等。Nonfitdimensions:Suchaskeyheight,keylength,axialtroughdepthandwheelhubdepth.,表6-1普通平键的键槽的剖面尺寸及极限公差(摘自GB/T1095-2003)mmTable6-1Thesectionsizesandlimitsizesofcommonflatkeyssectionsizesofthekeygroovesmm,注:(d-t)和(d+t1)两组合尺寸的极限偏差按相应的t和t1的极限偏差选取。但(d-t)的极限偏差应取负号。,平键结构示意图：Flatkeysabridgedgeneralviews,考虑测量的方便与可能Thinkabouttheconveniencesandpossibilitiesofmeasurements,1、尺寸精度设计（2）：Sizeprecisiondesign(2),平键联结的配合制Thefitsystemsofflatkeyconnections,公差带h8Tolerancezoneh8,Thesidefacesofkeys,Standardparts,Wheelhubs,Axialtroughs,Shaft-basissystemoffits,配合种类Fittypes,一般键与轴槽配合要求较紧，键与轮毂槽配合要求较松，相当于一个轴与两个孔相配合，且配合性质不同。Thefitrequirementsbetweenkeysandaxialtroughsarecommonlytighterwhilethefitrequirementsbetweenkeysandwheelhubsarelooseandtheyequaltothefitsbetweenoneshaftandtwoholesandthefitpropertiesaredifferent.国家标准规定三种公差带,构成三种配合形式：较松键联结、一般键联结和较紧键联结。Nationalstandardsprovidethreekindsoftolerancezonestoformthreekindsoffitforms:Loosekeyconnections,commonkeyconnectionsandtighterkeyconnections,平键公差带图Flatkeytolerancezonepicture,+0,-,b,h8,H9,D10,h8,N9,JS9,h8,P9,P9,键宽公差带Keywidthtolerancezone,轴槽公差带Axialtroughs,轮毂公差带Hubtolerancezone,较松键联结Loosekeyconnections,一般键联结Commonkeyconnections,较紧键联结Tighterkeyconnections,表6-2平键联接的配合与应用Table6-2Thefitsandapplicationsofflatkeyconnections,2、形位精度设计Shapeandpositionprecisiondesign,保证键宽与键槽宽之间具有足够的接触面积和可装配性Toguaranteethatthereareenoughcontactareaandassemblabilitybetweenkeywidthandkeywaywidth.轴键槽对轴的基准轴线和轮毂槽对孔的基准轴线的对称度公差Thesymmetrytolerancesthatshaftskeywayfacesshaftsdatumaxisandwheelhubfacesholesdatumaxis.一般可按对称度公差79级选取Itiscommonlyselectedandchosenaccordingtosymmetrytolerances7-9calss.,3、表面粗糙度的选择Theselectionsofsurfaceroughnesses,配合面FitsurfaceRa：1.63.2m非配合面NonfitsurfaceRa：6.3m。,4、轴的标注示例Thelabelexamplesofshaft,0.02A,50,-0.2,0,58r6（）,+0.060,+0.041,A,3.2,3.2,12.5,1.6,16N9（）,0,-0.043,1、标注槽深d-t1及公差Labelgroovedepthd-t1andtolerances2、标注槽宽b及公差Labelgroovewidthbandtolerances3、标注对称度公差Labelsymmetrytolerances4、标注表面粗糙度Labelsurfaceroughnesses,5、轮毂的标注示例Thelabelexamplesofhubs,58H7（）,+0.03,0,A,3.2,3.2,16JS9（）,0.021,0.02A,60.3,0,-0.2,1.6,1、标注轮毂深d+t2及公差Labelhubdepthd+t2andtolerances2、标注槽宽b及公差Labelgroovewidthbandtolerances3、标注对称度公差Labelsymmetrytolerances4、标注表面粗糙度Labelsurfaceroughnesses,四、花键配合的精度设计Precisiondesignsofsplinefits种类Types,Rectangularkey,Involutespline,Serrationspline,特点Features,可靠，强度高，可以传递较大的转矩。Independent,highstrengthandcantransmitbiggertorque孔、轴定心精度高和导向精度高Thecenteringprecisionandguideprecisionofholeandshaftarehigh,矩形花键结构示例Thestructureexamplesofrectanglesplines,Rectanglesplines,Internalsplines,Externalsplines,1、尺寸精度设计（1）Sizeprecisiondesign(1),基本尺寸：小径d、大径D、键槽宽B。Basicsizes:Minordiameterd,majordiameterDandkeywaywidthB尺寸精度：花键联结的主要要求是保证内、外花键的同轴度，以及键侧面与键槽侧面接触均匀，保证传递一定的转矩。国家标准规定采用小径定心，即把小径的结合面作为定心表面，规定较高的精度；其它两个尺寸规定较低的精度。Sizeprecision:Themainrequirementsofsplinecouplingsaretoguaranteethecoaxialitesofinternalandexternalsplinesaswellastheuniformcontactsofkeyssidefacesandkeywayssidefacestoguaranteetransmittingcertaintorques.Nationalstandardsprovideadoptingsmalldiameterfixedcenterwhichregardssmalldiametersfayingfaceascenteringsurfaceandprovideshigherprecision.Theothertwosizesprovidelowerprecisions.,1、尺寸精度设计（2）Sizeprecisiondesign(2),矩形花键的分类：Theclassificationsofrectanglesplines按使用要求分：分为一般使用与精密传动两种。Accordingtooperatingrequirements:Itisdividedintotwokindsascommonusageandprecisiontransmission按联结使用要求分：分为滑动、紧滑动和固定三种配合类型。Accordingtoconnectionusagerequirements:Itisdividedintothreekindsoffittypesasslippage,tightslideandfixed.每种情况下花键配合的公差等级都不相同。Thetolerancegradesofsplinefitsineachconditionaredifferent,配合制基孔制FitsystemHole-basissystemoffits,三种定心方式：Threekindsofcenteringways大径D定心LargediameterDcentering小径d定心Smalldiameterdcentering键宽B定心KeywidthBcentering,Thecenteringwaysofrectangularsplineconnections,国家标准GBT1144-2001矩形花键尺寸、公差和检验规定矩形花键用小径定心NationalstandardGBT11442001Thesizes,tolerancesandtestsofsquaresplinesprovidethatsquaresplinesusesmalldiameterfixedcenter,矩形花键结合的极限与配合Thelimitsandfitsofthecombinationsinsquaresplines,分为两种情况：Itisdividedintotwoconditions:一般用途矩形花键；Generalservicesquaresplines精密传动用矩形花键。Squaresplinesforprecisiontransmission为了减少加工和检验内花键用的花键拉刀和花键量规的规格和数量，采用基孔制配合。Weadoptbasicholesystemfitstoreducethespecificationsandquantitiesofsplinegaugesandsplinebroacheswhichareusedtoreduceprocessingandtestinginternalsplines.,2、形位精度设计Thedesignofformandpositionprecisions,因为小径是花键联结的定心尺寸，必须保证其配合性质，所以内、外花键小径d的极限尺寸应遵守包容原则，即花键孔和轴的小径不能超越最大实体边界。Becauseminordiameteristhecenteringdimensionofsplinecouplingsandmustguaranteeitsfitproperties.Sothelimitsizesofinnerandexternalsplinesminordiametersshouldabidebyenvelopingprinciplesthattheminordiametersofsplineholesandshaftsarenotsupposedt