某航空电机球轴承过热失效分析与改进研究_李世理.pdfVIP

某航空电机球轴承过热失效分析与改进研究∗

摘要:某航空电机在运转实验过程中出现异常噪音,拆解后发现电机轴系两端支撑球轴承已发生过热失效,出现润滑脂碳化、保持

架断裂和内外套圈磨损等现象。为了解决某航空电机球轴承出现过热失效的问题,对电机轴系两端轴承进行了失效分析,并提出

了改进方案。首先,根据经验对电机轴系两端球轴承进行了故障分析,并提出了多个结构改进方案;然后,采用COBRAAHS软件建

立了热-应力耦合的航空电机轴承-转子仿真分析模型,分别对不同的改进方案进行了接触应力和温度场分析;最后,对比了不同条

件下的仿真分析结果,得到了轴承过热失效机理,并提出了相应改进方案,结合实验对改进方案进行了验证。研究结果表明:转轴

受热变形是导致该航空电机球轴承过热失效的主要原因,转轴受热变形后挤压两端轴承,使得滚动体与滚道之间最大接触应力可

达2512.0MPa;过载条件下,加剧了轴承摩擦生热,导致温度急剧上升,最高可达219.2℃,润滑脂因高温碳化失效,不良的润滑条

件使轴承早期失效;将电机两端支撑轴承由深沟球轴承更换为角接触球轴承后,两端轴承最高温度为96.6℃,最大接触应力为

1866.1MPa,即降低了轴承工作温度,提高了轴承轴向承载能力,电机运转寿命超过1200h。

关键词:电机运转寿命;球轴承;轴承过热失效机理;转轴受热变形;角接触球轴承;接触应力和温度场分析;润滑脂碳化

Overheatfailuremechanismandimprovementschemeofballbearing

foraeroelectromotor

Abstract:Duringtheaeroelectromotorstestoperation,abnormalnoisewasdetected.Upondisassembly,itwasdiscoveredthattheball

bearingsatbothendsoftheelectromotorshaftsystemhadsufferedfromoverheatingfailure,greasecarbonization,cagefracture,aswellas

wearontheinnerandouterrings,amongotherissues.Toaddresstheoverheatingfailureproblemintheballbearingsofanaero

electromotor,afailureanalysisofthebearingsatbothendsoftheelectromotorshaftsystemwasconducted,andanimprovementplanwas

formulated.Firstly,afailureanalysisoftheballbearingsatbothendsoftheelectromotorshaftsystemwascarriedoutbasedonexperience,

andseveralstructuralimprovementoptionswereproposed.Subsequently,athermal-stresscoupledaeroelectromotorbearing-rotorsimulation

analysismodelwasestablishedusingCOBRAAHSsoftware,andcontactstressandtemperaturefieldanalyseswereperformedfordifferent

improvementschemes.Finally,theresultsofthesimulationanalysesundervariousconditionswerecomparedtoderivetheoverheatingfailure

mechanismofthebearings.Acorrespondingimprovementplanwasdevelopedandvalidatedthroughexperiments.Theresultsshowthatthe

heatdeforma