A Reliability Estimation of a CMTSC Considering Dynamic Clamping Force

Abstract

The reliability of coil type manual three-jaw self-centering chucks (CMTSCs) of machine tools impacts significantly on reliability and safe operations of machine tools. This paper carries out a detailed reliability estimation of a CMTSC, in which the dynamic clamping force of the chuck is considered. Initially, a mathematical model of dynamic clamping force of the CMTSC is established after analyzing forces of key components of the CMTSC. Subsequently, Taking the dynamic clamping force of the jaw as the generalized stress and the minimum clamping force specified by the national standard as the generalized strength a multi-function formula containing n-dimensional random variables is established based on the stress-strength interference model. Then, an improved first-order second-moment method is adopted to solve the formula already mentioned as a basis of that to calculate the reliability of the dynamic clamping force of the chuck. The results of this study indicate that the maximum rotating speed of the CMTSC is 1000 rpm, accordingly, the reliability of the CMTSC meets the requirements of the machining. The results of the paper have merits in reliability analysis, extreme rotational speed determination, and structural optimization of the CMTSC.