数控磨床主轴系统的可靠性建模与评估研究

Research on reliability modeling and evaluation of spindle system of CNC grinder

对北京第二机床厂某系列数控磨床主轴系统的故障数据进行处理,绘制主轴系统的概率密度函数散点图,初步假定函数模型,再利用最小二乘法估计未知参数,利用卡方检验和相关系数法进行拟合优度检验,最终确定主轴系统的分布类型为指数分布。根据所属分布类型计算主轴系统的平均故障间隔时间MTBF,平均维修时间MTTR,以及固有可用度A,对主轴系统的可靠性进行评估。所得结果已反馈到生产厂家并获得认可,对数控磨床整机可靠性的提升有重要意义。

This paper deals with the fault data of the spindle system of a series of CNC grinding machines in Beier Machine Tool Works,draws the scatter diagram of the probability density function of the spindle system,and preliminarily assumes the function model of the system.Then the least square method is used to estimate the unknown parameters,chi square test and correlation coefficient method are used to verify the goodness of fit,and finally the distribution type of the spindle system is determined as exponential distribution.The mean time between failures(MTBF),mean time to repair(MTTR)and inherent availability(A)of the spindle system are calculated according to the distribution type,and the reliability of the spindle system is evaluated.The result has been feed back to the manufacturer and approved,which is of great significance to the reliability improvement of CNC grinder.