Reliability evaluation of electro spindle based on no-failure data

Abstract

Electric spindle is a key functional component of CNC machining equipment including CNC machine tools, and its reliability level is a key bottleneck factor restricting the reliability of high-end CNC equipment. So far, the research on the reliability evaluation method of electric spindle is still in its infancy, and there is a lack of Systematic and complete theoretical support. The motorized spindle is a typical high-reliability and long-life product, and it is difficult to fail or fail due to obvious performance degradation within a limited test time. Therefore, the traditional reliability evaluation method based on statistical theory is not effective. Therefore, it is of great significance to carry out the early reliability test of the motorized spindle and the reliability evaluation of the motorized spindle without failure data, which is of great significance to reasonably evaluate the reliability level of the motorized spindle. At present, when there is no failure data or very little failure data for the motorized spindle of the machine tool, only the point estimate of the parameter or the one-sided confidence interval of the parameter can be calculated, and it is extremely difficult to obtain the point estimate and the interval estimate at the same time, which will affect the reliability analysis results. Consistency. In order to solve this problem, this paper takes a certain type of CNC machine tool motorized spindle as the research object, and determines the monitoring points and monitoring information according to the failure analysis of similar motorized spindles; combines the test information to evaluate the reliability of the motorized spindle without failure data. The reliability evaluation method of the motorized spindle proposed in this paper can effectively avoid the problem that the traditional method cannot be analyzed when there is no failure data, and provides a new idea for the reliability evaluation of the motorized spindle.