数控车床是一种机电一体化的产品，在生产和生活中起着非常重要的作用。由于数控车床结构复杂、工作环境恶劣、故障模式和故障原因多样，对数控车床进行故障分析是十分必要的，而故障分析则是数控机床可靠性评估的一个重要方面。 本文对收集到的数控车床的故障数据进行深入分析，并利用模糊数学理论研究了数控车床的可靠性。 本文从故障模式、故障原因和故障危害度三方面对云南机床厂生产的通用数控车床的故障数据进行详细分析，找出了该系列数控车床设计的薄弱环节；在此基础上，对故障频繁的子系统深入地进行了故障模式和故障原因的分析，而刀架系统则是数控车床故障最频繁的子系统，因而建立了以刀架系统故障为顶事件的故障树，通过对故障树的初步分析，得出了刀架系统故障树的全部最小割集，并利用三角模糊数对故障树进行了定量分析，得到了顶事件刀架故障的模糊概率。这一方法克服了传统故障树分析复杂系统时遇到的困难，同时又不排斥传统故障树的分析方法。 针对数控车床可靠性，本文采用模糊数学理论对整机进行了模糊综合评价，并建立了评判模型，不仅综合考虑了影响可靠性的多种因素，而且充分发挥了专家的作用，因此其评判结果具有一定的客观性。

Numerical control lathes which plays a very important role in production and life is a kind of mechanical and electrical products. Because of the complex configuration,severe working condition,failure modes and failure cause of diversity, it is very necessary for faulting analysis on the numerical control lathes and fault analysis is an important aspect in reliability assessment for numerical control lathes. This thesis deeply analyzed the fault data basing on the collected Numerical control lathes and made the reliability of numerical control lathe using the fuzzy mathematics theory. This thesis analyzed the production general numerical control lathe fault data of Yunnan machine tool plant from three aspects of the failure mode,the cause of the problem and fault harm degree,found this series of numerical control lathe design of the weak link. Based on the above analysis,this thesis deeply analyzed the subsystem of the fault frequent about the failure mode and the analysis of the cause of the problem,and CNC lathe tool system is the most frequent subsystem of the numerical control lathes fault,so we established the fault tree of the system fault of the top events. Through a preliminary analysis of the fault tree,we concluded that all minimum cut set of the CNC lathes system fault tree,and utilized the triangular fuzzy number to analyze the fault tree, and got the fuzzy probability of top tool of events fault. This method overcomes the difficulties of traditional fault tree analysis in complex system,and does not reject traditional fault tree analysis method. According to the reliability of numerical control lathe,this thesis adopted the fuzzy mathematics theory to evaluate the whole machine,and set up the evaluation model. Not only considering the various factors that influence the reliability but also making full use of experts, the evaluation result has certain objectivity.