【作者】 蔡源春；

【导师】 周云山；

【作者基本信息】 湖南大学 ， 机械工程， 2011， 博士

【摘要】 汽车无级变速技术能够减轻驾驶员的劳动强度,提高车辆的可驾驶性,使汽车在行驶过程中经常处于最优工作状态,并且改善汽车排放,是理想的汽车变速装置。在我国,金属带式无级变速器已在湖南江麓容大公司成功实现了产业化。然而,金属带式无级变速器在工程化的应用和产业化过程中,必须解决系统可靠性和如何进一步提高金属带式无级变速器燃油经济性的问题。特别在国外技术封锁的情况下,对金属带式无级变速器的可靠性及燃油经济性的研究,显得尤其重要。金属带式无级变速器的可靠性包括机械的可靠性及控制系统的可靠性,它影响无级变速器使用寿命及安全。围绕无级变速器可靠性,本文对带轮变形问题,机械系统可靠性测试及关键部件故障诊断和控制系统的可靠性分析及容错控制这几项关键技术展开了研究。对于带轮的变形,本文建立国产金属带式无级自动变速器从动带轮三维模型,利用有限元方法,分析了轴向力、速比对带轮变形的影响,并建立了带轮最大变形量和最大变形位置分布的数学模型,再通过对比现有的实验数据,验证了有限元分析结果的有效性。分析结果表明,速比是影响最大变形量位置的主要因素,轴向力和速比同时影响变形量的大小,所建数学模型和分析方法对带轮的设计,效率分析以及疲劳寿命研究具有重要意义。同时,本文针对无级变速器的机械系统可靠性,设计了无级变速器可靠性的室内试验系统,试验系统利用可靠性试验场测试数据,将速比,输入转速以及转速转矩作为无级变速器的负载,利用小波分析方法,滤除对疲劳损伤影响较小的高频信号,然后利用试验系统进行复现。对于轴承这一重要的承力部件,利用自适应AR方法,寻找轴承故障的频谱特征,并且利用神经网络对故障样本训练,判断轴承是否存在故障。在控制系统的可靠性方面,本文利用潜在失效分析和故障树分析方法分析了无级变速器的潜在失效模式及失效效果,根据无级变速器的潜在失效模式,设计了电控系统的容错控制规则,并且通过实车试验进行验证。围绕无级变速器燃油经济性,本文对系统损失如何影响燃油经济性,降低夹紧力对传动效率的影响和燃油经济性的测试这几项关键技术展开了研究。本文首先基于液压泵损失和金属带及带轮机构损失的试验数据,建立了无级变速器的损失模型及油耗评价模型。对比实际的测试数据,验证了模型的准确性,然后利用模型分析了不同的工况下液压泵损失和金属带及带轮的损失对油耗的影响。为分析降低夹紧力对于传动的影响,本文利用滑移率控制策略,降低无级变速器的夹紧力,以提高金属带式无级变速器的传动效率。通过MATLAB/SIMULINK建立仿真模型表明,基于滑移率控制能将金属带式无级变速器的传动效率提高10%左右。对于无级变速器的油耗测试,本文基于硬件在环仿真的原理,建立无级变速器的测试系统。试验系统利用整车道路滑行试验数据,建立道路负载模型,再通过控制变频交流电机,动态模拟道路负载驾驶员动作。建立的无级变速器传动系的虚拟试验系统,为无级变速器的电控单元标定和经济性测试提供了可再现的试验环境。对于金属带式无级变速器的燃油经济性以及可靠性研究中,本文有以下几点创新工作:(1)应用有限元的方法,分析了轴向力对金属带轮角度的影响,得到了变形规律,为减小金属带偏磨提供了理论分析的方法,有助于提高系统的可靠性;(2)首次利用小波分析方法并结合试验场测试数据,开发了金属带式无级变速器的室内可靠性试验系统,并且基于自适应AR谱的方法,分析了轴承的失效模式,为传动机构的轻量化设计和降低金属带传动噪声进行了很有价值的尝试;(3)开发了基于硬件在环仿真的燃油经济性测试系统,缩短了CVT的开发周期,具有工程应用价值;(4)采用潜在失效分析和故障树分析方法设计了控制系统的故障诊断和容错控制规则,提出了故障诊断控制策略,有利于提高系统的安全性。更多还原

【Abstract】 The Continuously Variable Transmis sion(CVT)is suppo sed to be theideal transmis sion，because it can decrease the driver’s w-ork，improve thedriveability，offer the brilliant vehicle Performance and emis sion Now it ismore and more Popular with the Chine se customer and motor manufacturerHow-ever，in the engineering application，the transmis sion lo s s have to bedecreased and the reliab ility of CVT are nece s sary to be improved Thetransmis sion lo s s will affect the fuel economy and the system reliability，including the mechanical system reliability and electronic system，reliability，is a keY point to the transmis sion serVice life Therefore，the setwo factors are very important to the CVT engineering applicationWith the reliabilitY of CVT，the finite element method is apPlied onthe deformation and stre s s analys is Based on a 3-D model of secondaryPulleY of Continuously Variable Transmis sion，the finite element method isused to analyze the pulleY deformation with certain axial force and ratioAfler that，the mathematic model about maximum PulieY deformation valueand Po sition are develoPed with the re sult of finite element methodComparing with the experimental data，the finite element method isvalidated The resuIt show that the ratio is the mo st important factor toaffect the po sition of maximum deformation and the axial force and ratioaffect the value of deformation together The mathematic model andanalyzing method is useful in the PulleY de sign and CVT efficiencY re searchAfler the stre s s and deformation analys is，the te st rig about mechanicalreliability is develoP ed Based on the CVT data of input torque，input sPeedand ratio，c01lected in the Proving ground，the~-avelet multi re solution isused to filter out the high frequencY s ignals，which had little effect on thefatigue damage of CVT Then the CVT rat io and input speed were send tothe CVT cont rolier and motor controlier re spectively and then the obj ectdata is rePeated the te st rig The TIC(The il inequalitY coeffic ient)valueshow that the system is a effective te st Platform fo r the reliability Based onthe theorie s of adaptive AR spectrum and neural network，a fault diagno s ismethod for bearings in CVT is P re sented The method use s adaptivefiltering technique to filter the Vibration signals of bearings，sets up an AR model to extract the features 0f faUItY bearings．and utilizes neural networkto clas Sify the faults The te st re sults Show that the apP roach canefiectively identify the faUIt patterns of transmis Sion bearings About thereliability 0fCVT C0ntroller，the Failure Mode and Effect Arialysis(FEMA)and FauIt Tree Aanalysis(FTA)method are used to do the Potential failuremode and efiects analys is AcC0rding to the Porential failure mode．thediagnose code and tolerance control strategy are deVeloPed Theexperimental data show that the tolerance Control strategy is effective toProtect the transmission and the vehicle With the loss of CVT，a simulationmodel with MATLAB M-C0de is deVeloPed to evaluate the affection of Pumploss and beIt loss to the vehicle fue 1 consumption，based on the loss data ofPump and belt Comparing with the te st rig data．the Simulation re suIt isconfirmed to be accurate For improVing the the efficiencY of CVT．the slipcontrol strategy is applied on decreasing the Clamping force and increasethe friction coeffic ient The Simulation show that it is an efiectiVe methodto improVe the CVT’S efficiencY under the Pre sent teChnology and CVT lossAfter that．a test rig for the efficiency test is deVeloped hased on thePrinciple of hardware in the looP Simulation AcCOrding to the vehicleSliding data．a vehicle load model is USed in the te st rig and repeated bY theA/C motor And the driver model is simulated by the electronic throttleC0titr01With CVT fuel economy and reliabilitY．S0me innovation work can beseen in the reseach：(1)AcC0rding to the FEM re sults，a law-about pulleydeformation．in different axial force and ratio．is developed for reducing thealigement Setting and improving the mechartical system reliability(2)Aw-avelet is used in the ground test signals processing．for developing theCVT reliability test system.Meanw-hile，a fauIt diagnosis method，based 0nthe adaptive AR spectrum．with bearings in CVT．is presented in this paperThe test system is helpful in analyzing the CVT C0mponentsreliability(3)Based 0n the Principle 0f hardware in the loop Simulation，aninnoViation fuel eConomy te st System is develoPed for improVing the CVTdeVe loping effic iencY (4)the FEMA and FTA method are used to d0 thepotential failure mode and efiects analys is According to the potential failure mode，the diagnose code and tolerance control strategy are developed for guarantee the passanger safe更多还原