Research on measuring method and instrument of motorized spindle

Abstract

Tolerance has great impact on the cost and quality of a product. This article proposed a dimensional precision measurement method for the shaft and the flange in motorized spindle and designed a special instrument for this purpose. First, the measured dimension errors and problems were analyzed, which has two geometrical dimensions. Second, the measuring methods for them were proposed. A three-stepped plug gauge and coloring method were applied to measure the first dimensional precision. The second dimensional precision, as in space dimension, is the distance from the flange end face to intersection line of tapered surface and inner bore surface and was converted into the distance from the end face to the tangent point between a ball and tapered surface and then was measured with a simple method. Mathematical derivation was conducted and then a simple mathematical model was applied to map the relationship between these two distances. Self-centering principle and structure were designed to improve the positional accuracy of gauge. Third, according to the proposed dimensional precision measuring method, a composite instrument was designed, which can measure the two required geometrical dimensional precision of shaft and flange. Finally, the manufactured instrument was applied to actual production process, and the results validated the effectiveness and correctness of the proposed method.