Influence of structural and technological factors on parameters of contact interaction of conical profile connections of spindle units of multi-purpose CNC machines

Abstract

One of the most critical connections of CNC machine tools is the spindle unit. It should be noted that machines with high-speed processing of products (high-speed cutting (HSC)) are widely used at present. These machines are characterized by: high speed of rotation of the main drive, increased cutting speed, the use of new tool materials, as well as stricter requirements for the quality of manufactured products. In this regard, the solution of problems related to improving the efficiency of metal-cutting machines, in particular multi-purpose CNC machines (MS), by improving the design of spindle units through the introduction of innovative solutions that increase their reliability, becomes significant. The article analyzes the contact interaction of profile connections with an equiaxed contour with a number of edges equal to three in relation to the “spindle-mandrel” connection of a multipurpose machine. The solution of the spatial contact problem is reduced to the solution of the plane contact problem of elasticity theory using the response surface method, which is based on the method of planning experiments and least squares. The nature of the distribution of contact pressures over the interface zones during external load transmission is determined, and the dependences of contact pressures and angles on the external load are determined depending on the design parameters (gaps) of the connection. It was found that when the fit gap in the profile connection changes from 18 to 228 microns, the maximum contact pressure increases to 41%, while the contact stiffness of the profile connection decreases to 22%.