【作者】 郑玉彬；

【导师】 申桂香；

【作者基本信息】 吉林大学 ， 机械工程（工业工程）， 2019， 博士

【摘要】 可靠性评价是可靠性研究的重要内容之一,本文以“高档数控机床与基础制造装备”国家科技重大专项课题和吉林省科技发展计划项目为依托,结合目前行业对数控机床大功率电主轴的需求,对电主轴加速可靠性试验设计、电主轴可靠性试验测试、可靠性建模及评估技术展开研究。本文的研究工作主要包括:(1)集成FMECA/DEMATEL/FMMESA的电主轴故障分析首先基于电主轴单元结构及功能原理,进行电主轴单元子系统划分,然后对电主轴现场可靠性试验故障信息进行整理和分析,针对单一故障分析方法无法明晰故障机理问题,提出一种集成FMECA、DEMATEL与FMMESA的故障分析技术。基于FMECA确定各组件故障模式比例,应用DEMATEL通过故障相关性分析及“四度”计算明确关键故障模式形成机理,引入FMMESA法对原因故障模式进行故障—环境影响定性分析,实现关键组件模式、关键故障原因及环境应力评定。集成的电主轴故障模式分析方法弥补了传统方法的不足,为后续电主轴可靠性试验的测点设计、传感器选择、可靠性建模及评估等研究提供参考依据。(2)基于威布尔分布的电主轴可靠性试验时间设计电主轴是高可靠长寿产品,为快速评估电主轴可靠性水平,进行台架试验模拟实际工况下电主轴加速可靠性试验时间设计。为消除当前步进加载试验在载荷切换中引起的偏差,提出基于现场电主轴可靠性信息,应用生存分析与似然函数原理进行可靠性模型参数估计,应用Hollander检验准则进行模型检验;结合载荷信息进行载荷谱编制及加载谱研究。据此结合修正Miner疲劳损伤累积理论,进行形状参数已知,基于威布尔分布模型的电主轴寿命试验加速因子确定,结合新研制产品平均寿命水平进行恒定加载下加速寿命试验时间设计,为实验室可靠性试验测试奠定基础。(3)定时截尾电主轴可靠性测试及试验信息采集为有效控制试验参数,缩短试验时间,电主轴可靠性测试试验采用定时截尾方式在电主轴可靠性试验台上进行,故从机械结构、控制系统等方面阐述电主轴可靠性试验台结构。测点选择直接影响测试信息的准确性,为降低误差,基于故障分析进行测试信号确定、载荷测试点初选,应用灰色理论等方法进行测点优选及传感器选择,并形成测试试验方案。在模拟电主轴实际工况的前提下,结合工程实际制定测试程序,开展电主轴可靠性测试试验,并采集测试信号信息,对信息进行初步分析以确定退化特征参数。(4)无突发失效信息下电主轴可靠性评估在电主轴可靠性试验台上进行的电主轴加速可靠性试验,常常没有突发失效现象产生,此时传统的基于统计原理的可靠性建模及基于Bayes方法的小样本理论均不奏效。结合现场试验电主轴可靠性模型及试验测试信息,从竞争失效角度提出了一种基于单侧置信限建模基本失效率、以性能退化数据为协变量的部分分布竞争风险建模及寿命评估方法,弥补传统将无失效数据作为截尾数据处理及忽略突发失效影响带来的建模偏差。并将建立的部分分布竞争风险模型、常用的Wiener过程模型与企业目标电主轴可靠性模型进行对比,验证所提方法的合理性。丰富并完善电主轴可靠性技术体系。本文所提出的方法解决了高可靠性长寿命产品在缺乏失效数据的情况下难以展开可靠性评估的问题。可以为无突发失效信息下的可靠性建模与寿命评估提供参考和借鉴。更多还原

【Abstract】 Reliability evaluation is one of the important contents of reliability research.Based on the major national science and technology project of "High-grade CNC machine tools and basic manufacturing equipment" and Jilin Province’s science and technology development plan project,under the industry’s demand for high-power motorized spindle of CNC machine tools,this paper studies the accelerated reliability test design,reliability test,reliability modeling and evaluation technology of motorized spindle.The main work of this paper are as follows:(1)Failure analysis of motorized spindle integrated with FMECA/DEMATEL/FMMESAFirstly,based on the structure and functional principle of motorized spindle unit,the subsystem of motorized spindle unit are divided,and then the fault information of field reliability test of motorized spindle is sorted out and analyzed.Aiming at the problem that a single fault analysis method cannot clarify the fault mechanism,a fault analysis technology integrating FMECA,DEMATEL and FMMESA was proposed.Based on FMECA analysis,the proportion distribution of failure modes of each component is determined.DEMATEL is applied to define the formation mechanism of key failure modes through failure correlation analysis and "four-degree" calculation.Finally,FMMESA method is introduced to conduct failure-environmental impact qualitative analysis to the root of failure modes,so as to realize critical component modes,key failure causes and environmental stress assessment,and to make up for the bias and deficiency of traditional single fault analysis method.It provides a reference basis for the subsequent design of measuring points,sensor selection and reliability growth of motorized spindle reliability tests.(2)Reliability test time design of motorized spindle based on Weibull distributionMotorized spindle is a product with high reliability and long life.In order to quickly evaluate the reliability level of motorized spindle,bench tests are conducted to simulate the design of accelerated reliability test time of motorized spindle under actual working conditions.In order to eliminate the deviation caused by load switching in current stepping load test,the reliability model parameter estimation is proposed using the survival analysis and likelihood function principle based on the field reliability information of the electric spindle,then the model inspection is carried out using Hollander inspection criterion.Combined with load information,load spectrum compilation and load spectrum research are carried out.According to this,combined with the modified Miner fatigue damage accumulation theory,the acceleration factor of motorized spindle life test is determined under the Weibull distribution model with known shape parameters.Combined with the average life level of the newly developed product,the accelerated life test time design under constant loading is carried out,which lays a foundation for laboratory reliability test.(3)Timing Truncated Reliability test and Test Information Collection of Motorized SpindleIn order to control the test parameters effectively and to shorten the test time,the reliability test of the electric spindle is carried out on the reliability test table of the motorized spindle.Therefore,the structure of the reliability test bed of the motorized spindle is described from the aspects of the mechanical structure and the control system.The selection of measuring points directly affects the accuracy of test information.In order to reduce the error,the test signal is determined based on fault analysis,the primary selection of load test points is carried out,and the grey theory is used to select the measuring points and sensors,and the test scheme is formed.On the premise of simulating the actual working conditions of the motorized spindle,combining with the engineering practice,the test program is formulated,the reliability test of the motorized spindle is carried out,the test signal information is collected,and then the information is preliminarily analyzed to determine degradation characteristic parameters.(4)Reliability Evaluation of Motorized Spindle without Sudden Failure InformationThere is often no sudden failure phenomenon when carring out the accelerated reliability test of motorized spindle under simulated actual working conditions on the motorized spindle reliability test bench.At this time,the traditional reliability modeling based on statistical principle and the small sample theory based on Bayes method are not effective.Based on the reliability model of motorized spindle in field tests and experimental test information,a partial distributed competitive risk modeling and life assessment method from the perspective of competitive failure is proposed,in where modelling the basic failure rate by one-sided confidence limit method and taking performance degradation data as covariates.Finally,the partial distributed competitive risk model and Wiener process model are compared with the target motorized spindle reliability model of the enterprise to verify the rationality of the proposed method.It is compared with the degradation process modeling method to verify its rationality,enrich and improve the reliability technical system of motorized spindle.The method proposed in this paper solves the problem that it is difficult to evaluate the reliability of high-reliability and long-life products without failure data.It can provide reference for reliability modeling and life evaluation without sudden failure information.更多还原