中文摘要：

液压系统是数控磨床的关键组成系统，其可靠性高低对磨床的加工质量和效率有重要的影响。根据采集到的故障数据，进行统计分析与教据处理，然后利用常用的故障分布类型，分别进行拟合检验和优选，获得了数控磨床液压子系统故障间隔时间的分布函数及相关参数。根据建立的数学模型计算可靠性指标MTBF，与观测值进行比较，验证所建模型的正确性，为数控磨床可靠性提升提供理论依据。这里所建模型及评估方法已应用于某机床厂的可靠性提升工程中。

英文摘要：

Hydraulic system is a key component of the system of CNC grinding machines, which has a significant impact on the reliability and the efficiency of grinder.The statistic analysis and data processing are performed according to the failure data acquired, and the fitting inspection and optimization are then performed respectively utilizing common failure distribution type, thereby obtaining the distribution function and related parameters of the numerical control grinding machine with hydraulic subsystem fault interval time. According to the mathematical model, the reliability index MTBF is calculated, the accuracy of the model is verified, and the reliability of CNC grinding machine is provided. The model and the evaluation method have been applied to the reliability engineering of a machine tool facroty.