Q/SZJ191001-2017懸置扭矩軸分析規(guī)范SpecificationOfPowertrainMountingNeutralTorqueAxisAnalysis20XX20XX-09-30實(shí)施20XX-08-28發(fā)布XXXX汽車工程技術(shù)有限公司發(fā)布Q/SZXX-X-2017懸置扭矩軸分析規(guī)范范圍本標(biāo)準(zhǔn)規(guī)定了懸置扭矩軸分析的方法。本標(biāo)準(zhǔn)適用于CAE部門懸置扭矩軸分析。規(guī)范性引用文件無(wú)。術(shù)語(yǔ)和定義無(wú)。摘要Abstract動(dòng)力總成是整車激勵(lì)的主要激勵(lì)源之一。正確的動(dòng)力總成懸置位置布置是NVH的一項(xiàng)主要工作。不同的發(fā)動(dòng)機(jī)需要不同的懸置方案。當(dāng)前主要針對(duì)線性陣列的四缸發(fā)動(dòng)機(jī)（或線性陣列四缸和V型陣列六缸）的懸置方案成為中性扭矩軸懸置方案，也可以稱之為扭矩旋轉(zhuǎn)軸。扭矩軸懸置方案基本概念是解耦并滿足安裝承載和扭矩反作用的兩項(xiàng)支撐功能要求。安裝承載功能要求在垂向剛度較小來(lái)支撐動(dòng)力總成本身重量。扭矩反作用功能要求與非線性襯套彈簧協(xié)調(diào)來(lái)滿足較低的剛度與振動(dòng)。在怠速工況下，激勵(lì)力的頻率范圍非常接近動(dòng)力總成的剛體模態(tài)頻率。這意味著懸置的隔振后動(dòng)力總成頻率要低于發(fā)動(dòng)機(jī)更高轉(zhuǎn)速相應(yīng)頻率。因此，對(duì)于怠速工況下，懸置布置過(guò)程中相對(duì)于弱化扭矩反作用支撐功能，優(yōu)先調(diào)節(jié)安裝承載功能對(duì)應(yīng)的剛度以避免傳遞振動(dòng)。對(duì)于線性陣列四缸發(fā)動(dòng)機(jī)，怠速工況下最主要的激勵(lì)力是繞曲軸的二階扭矩。扭矩軸定義為當(dāng)受到作用于曲軸的正弦轉(zhuǎn)矩激勵(lì)時(shí)動(dòng)力總成繞其旋轉(zhuǎn)的軸。當(dāng)懸置布置在扭矩軸上時(shí)，系統(tǒng)輸入力只會(huì)在懸置安裝點(diǎn)輸出純轉(zhuǎn)動(dòng)，而不會(huì)輸出移動(dòng)。Thepowertrainisoneofthemajorsourcesforvibrationsinducedtoavehiclestructure.AnaccuratelayoutofthePTmountingsystemismajortopicofNVHdevelopmentwork.DifferentarchitecturesofenginedorequiredifferentPTmountingconcepts.CurrentPTmountingconceptforvehicleprogramsthatareequippedwithline-fourcylinderengines(oracombinationofline-fourandV-6engines)isthesocalledNTA-mountconcept.NTAstandsforneutraltorqueaxis.AnothertermsometimesusedforitisTRA(Torquerollaxis).ThebasicideaoftheNTAmountingconceptisadecouplinginfunctionofloadbearingmountsandtorquereactionsupports.TheloadbearingmountsneedtohaveacertainminimumstiffnessinverticaldirectiontosupporttheforcesresultingfromtheweightofthePT.Thetorquereactionsupportscanbetunedwithnonlinearspringratessothattheyhavelowstiffnessforsmallvibrationlevels.InidleconditionthefrequencyrangeoftheexcitationforcesisquiteclosetotherigidbodymodesofthePT.ThismeansthattheisolationofthemountingsystemislowerthanforhigherRPMsoftheengine.So,especiallyforidleconditionthelayoutofthemountingsystemshouldavoidtransmittingvibrationthroughthecomparablestiffloadbearingmountsratherthanthesoftertorquereactionsupports.Majorrequisitesforthatareoptimizedlocationsoftheloadbearingmounts.KnowingtheinertiapropertiesofaPTcombinationandthevectorofexcitationforcesonecancalculatetheoptimummountlocationsinthesensethatthetransmittedforcesthroughtheseloadbearingmountsareminimized.Fortheline-fourenginesthemostsignificantforcecomponentinidleconditionisthesecondordercombustiontorquearoundtheenginecrank.TheNTAisdefinedastheaxisthePTdoesrotatearoundwhenaunitharmonictorquearoundit’scrankisapplied.Asonlyarotationisresultingfromthesysteminputthereisnoforcetransmittedthroughamountincasethemountislocatedonthisaxisofrotation.圖1懸置模型流程圖分析分析初始化InitiateAnalysis收集動(dòng)力總成轉(zhuǎn)動(dòng)慣量信息CollectinertiainformationonPT建模BuildPTmodelaccordingtoprocedureusingtemplatemodeler計(jì)算扭矩軸CalculateorientationofNTAaxis對(duì)所有安裝在本車的動(dòng)力總成進(jìn)行計(jì)算RepeatprocessforallPTinvehicleprogram繪制扭矩軸PostprocessresultsbydrawingofNTAsofallPTsinvehicleprogram比較所有扭矩軸后選擇合適的懸置安裝位置LocateloadbearingPTmountsonbestcompromiselocationofallNTA’s圖2流程圖工具描述ToolDescription動(dòng)力總成模型要輸入動(dòng)力總成的轉(zhuǎn)動(dòng)慣量參數(shù)，位置和方位可通過(guò)模板輸入，扭矩軸通過(guò)程序計(jì)算。ThePTmodelisbuiltbasedontheinformationonPTinertia,PTlocationandorientationbymeansoftemplatebuilder.TheNTAaxiscalculationisdonebyprogram.建模和分析過(guò)程Modeling/AnalysisProcedure只需要建立簡(jiǎn)單的動(dòng)力總成剛體模型OnlythesimplifiedmodelingtechniqueresultinginarigidPTmodelcanbeusedforthiscalculation假設(shè)和限制Assumptions/Limitations動(dòng)力總成被假定為具有6個(gè)自由度的剛體。由于總布置的限制懸置位置一般很難恰好布置在扭矩軸上。ThePTisassumedtobearigidbodywith6degreesoffreedom.PackagelimitationstypicallydonotallowtoplacetheloadbearingmountsexactlyontheidealNTAaxis.載荷和邊界條件Loads/BoundaryConditions約束僅計(jì)算扭矩軸，動(dòng)力總成無(wú)需約束。如果除了計(jì)算扭矩軸，還要計(jì)算彈性軸，則需要考慮懸置位置。默認(rèn)懸置約束1~6自由度。ThePTisnotconstraintforcalculatingtheNTA.BesidestheNTAasocalledelasticaxiscanbecalculatediftheenginemountsareconsidered.ThentheenginemountsgetconstraintonvehiclesidebySPC1-6.載荷無(wú)。結(jié)果Results結(jié)果格式ResultsFormats結(jié)果要顯示出所有懸置安裝點(diǎn)位置和動(dòng)力總成質(zhì)心位置以及所有扭矩軸的方位。分別輸出整車頂視圖和后視圖。其它信息如發(fā)動(dòng)機(jī)實(shí)際安裝位置也可以顯示。TheresultsdisplayshouldshowallmountspositionsandtheCGofthePTstogetherwiththecalculatedNTAaxisorientation.Thisshouldbedoneforthevehicletopviewandrearview.Additionalinformationthatisneededtogeneratesuchagraphistheenginemountpositions.圖3結(jié)果性能要求PerformanceRequirements無(wú)。分析要求ANALYSISREQUIREMENTS無(wú)。參考文件DOCUMENTATION無(wú)。聯(lián)系人CONTACTS無(wú)。例子EXAMPLES無(wú)附錄為了計(jì)算扭矩軸的位置和方位，先在動(dòng)力總成坐標(biāo)系中，建立方程式1。從而對(duì)于諧波系統(tǒng)輸入力，可以得到其響應(yīng)(1)對(duì)于自由狀態(tài)，沒(méi)有剛度輸入，則方程式1可以簡(jiǎn)化為：(2)輸入單位轉(zhuǎn)矩，表達(dá)式如下：(3)上標(biāo)表示輸入力矢量在動(dòng)力總成坐標(biāo)系下。將表達(dá)式3代入方程式2中，則輸入力矢量在動(dòng)力總成的主慣性坐標(biāo)系下進(jìn)行轉(zhuǎn)換。在此坐標(biāo)系下，質(zhì)量矩陣M已定義。系統(tǒng)將繞動(dòng)力總成質(zhì)心進(jìn)行轉(zhuǎn)動(dòng)，同時(shí)也意味著質(zhì)心在扭轉(zhuǎn)軸上。將質(zhì)心坐標(biāo)矢量(4)代入方程式2，可以求解出方位角，同時(shí)位移量為零。上標(biāo)表示在動(dòng)力總成坐標(biāo)系下。方位角表示扭矩軸在空間的方位。從動(dòng)力總成在整車的位置、方位和轉(zhuǎn)動(dòng)慣量等信息后，可以從慣性坐標(biāo)系轉(zhuǎn)換成主慣性坐標(biāo)系下信息。這種轉(zhuǎn)換可以將扭轉(zhuǎn)軸逆轉(zhuǎn)回整車坐標(biāo)系下。見上節(jié)圖示，圖中不僅包含了動(dòng)力總成質(zhì)心坐標(biāo)，也包含了扭轉(zhuǎn)軸兩個(gè)端點(diǎn)。發(fā)動(dòng)機(jī)左右安裝點(diǎn)的Y坐標(biāo)也顯示出來(lái)了。至于計(jì)算彈性軸，還需要懸置剛度信息。代入方程式1中剛度矩陣，隨后過(guò)程與計(jì)算扭轉(zhuǎn)軸一樣。ForthecalculationofthepositionandorientationoftheNTAaxisoneshouldsetuptheequationofmotionofthePTsystemasshowninequation(1).Forharmonicsysteminputs,onecancalculatetheresponsefrom:(1)Astheunconstraintcaseisconsideredhere,thereisnostiffnessandsoequation(1)getssimplifiedto(2)Theinputtothesystemisaunitmomentaroundthecrank.Thiscaneasilybeexpressedas(3)WheretheindexindicatesthattheforcevectorfisdefinedinthePTcoordinatesystem.Forinsertingequation(3)to(2)theforcevectorshouldbetransformedtotheprinciplecoordinatesystemofthePT.ThisisthecoordinatesystemthemassmatrixMtypicallyisdefinedin.ThesystemwilldoastablemotiononlyaroundthePTCGwhichmeansthattheCGwillbeontheNTAaxis.PuttingtheCGpositionvector(4)Intoequation(2)onecansolvefortherotationsasthetranslationsarezero.Theindexdenotestheprinciplecoordinatesystem.TheserotationsdescribetheorientationtheNTAaxisinspace.Fromtheinformationonthe