【作者】 李世龙；

【导师】 王时龙；

【作者基本信息】 重庆大学 ， 机械制造及其自动化， 2013， 硕士

【摘要】 数控机床是制造业的基础，是衡量制造工艺水平的重要指标，它的质量和可靠性水平的高低直接影响了我国制造业的发展。本文依托国家科技重大专项（2009ZX04001-81和2009ZX04011-041），并且结合企业实际情况，提出了基于威布尔分布的数控机床可靠性建模评估技术；考虑到数控机床的复杂性与数据的不确定性，提出了基于改进的模糊层次分析法的数控机床可靠性分配方法；系统的分析了数控机床的故障数据；结合企业管理规范，制定了基于寿命周期的数控机床可靠性增长及管理办法。基于某企业的大型数控滚齿机，本课题主要完成的研究工作包括：①分别采用单威布尔和混合威布尔分布对数控机床故障间隔时间数据进行建模。以国产某数控滚齿机为研究对象，选择了合理的试验方案，跟踪收集了大量故障数据，以及经过这些故障数据的处理分别建立故障间隔时间数据的单威布尔和混合威布尔分布的模型，同时对这两种分布进行了对比分析。在确定分布模型的基础上，计算数控机床可靠性指标的估计值。②鉴于数控机床的复杂性，影响可靠性分配的因素较多且很多因素都不能精确测量，可靠性分配比较困难。提出了基于改进的模糊层次分析法的数控机床可靠性分配方法，综合考虑影响数控机床可靠性分配的多种因素，通过专家打分得到模糊判断矩阵，而且此方法不需要进行一致性检验，通过迭代算法提高了计算的精度。③采用主次图法对数控机床整机进行了故障分析，发现电气系统、主轴部件、液压系统为数控机床可靠性的薄弱环节。分别对电气系统、主轴部件和液压系统进行了详细的故障分析，从而得知了具体的故障模式和故障原因。针对故障分析的结果对数控机床进行了部分可靠性改进设计，提高了数控机床的可靠性。④制定了基于寿命周期的数控机床可靠性增长与管理技术。根据故障分析结果，制定了机械、电气及液压的可靠性设计准则。为了确保可靠性设计的实施，建立了可靠性设计的审查办法；针对外购、外协件是主要导致机床故障的问题，重点建立了外购、外协件的可靠性保障措施。在生产阶段建立了工序质量保证办法，对于关键工序的提出具体的保障措施。提出了使用阶段的可靠性保证措施。更多还原

【Abstract】 The CNC machine tool, as the basis of manufacturing industry, is an importantindicator to measure the level of manufacturing process. Its quality and reliabilitydirectly affects the development of China’s manufacturing industry. In the paper, underthe support of National Science and Technology Specific Project(2009ZX04001-81and2009ZX04011-041), and in view of the actual situation of enterprises, assessmenttechniques of CNC machine based on the Weibull distribution are developed; in light ofthe complexity of the CNC machine and uncertainty of data, the method of reliabilityallocation for CNC machine based on improved fuzzy analytic hierarchy process isproposed; failure data of CNC machine is analyzed systematically; methods ofreliability growth and management for CNC machine based on life-cycle, inconjunction with standards of enterprise management, are developed.Based on the large CNC gear hobbing machine of an enterprise, the subject mainlycompletes the following research works:①The data of CNC machine time between failures are modeled using a singleWeibull and mixed Weibull distribution respectively. Under certain domestic CNC gearhobbing machine as the research object, the reasonable testing program is selected. Alarge number of failure data are tracked and collected. The single Weibull and mixedWeibull distribution of time between failures are established by conducting these failuredata respectively. Meanwhile, the two kinds of distribution are analyzed and compared.Based on the determination of distribution model, the estimated value of the reliabilityindex of CNC machine is calculated.②In view of the complexity of CNC machine, the number of factors which affectreliability allocation of CNC machine are large, and many of them cannot be measuredaccurately, which consequently results in the difficulty of the reliability allocation. Themethod of reliability allocation for CNC machine based on improved fuzzy analytichierarchy process is proposed, which fully considers many kinds of influencing factorsof reliability allocation. The fuzzy judgment matrix is obtained by expert scoring andthere is no need to examine the consistency of the fuzzy judgment matrix. The accuracyof calculation is improved by the iterative algorithm.③The primary-secondary graph method is used to analyze the failures of thecomplete CNC machine, finding the electrical system, spindle unit and hydraulic system are the weak link in the reliability of CNC machine. In order to find the specific failuremodels and failure causes, the date of the electrical system, spindle unit and hydraulicsystem are analyzed in detail respectively. Based on the result of failure analysis,improvements of reliability design for the CNC machine are conducted partly toimporve the reliability of CNC machine.④Reliability growth and management techniques of CNC machine based on thelife-cycle are developed. According to results of the failure analysis, the reliabilitydesign criteria of mechanical, electrical and hydraulic parts are proposed. To ensure theimplementation of reliability design, the review approaches of reliability design aredeveloped. As the outside purchased and manufactured products are the most mainreasons of causing the failure of CNC machine, the guarantee measures of them arefocused and established. During the production phase, the safeguard measures of theprocess quality are proposed, especially the specific security measures of the keyprocesses. Meanwhile, the guarantee measures in the use-phase of CNC machine areestablished.更多还原