Research On Contact Characteristics Of Polygon Taper Shank

High-speed shank is an important part of modern high-speed machine tool. Theaccuracy and efficiency of workpiece and the tool life are determined by thetechnical level of spindle and shank. Currently, the requirement of the spindle speedis promoted gradually in the field of machining. At the same time, the reliability oftool system is also required much more improvement. Polygon taper shank is one ofthe most widely used tool holders in high-speed machining field, of which the taperhas a triangular-like structure, and the edge is an arc transition. This kind of structurenot only holds neutrally and easily assembled and disassembled but also receives lessstress concentration and higher torque transmission. This paper focuses on thecontact characteristics of the taper shank.Starting with the basic theory of connection profile of the polygon taper shank,the principle of keyless connection and relevant calculating theory were studied onthe connection profile. Based on these basic theory, the contact characteristics of thepolygon taper were analyzed, and finally a measuring experiment for polygon shankwas conducted. The studies are as follows.Firstly, based on the characteristics of polygon taper shank, the principle ofpolygon taper shank was analyzed and the calculation method for sectional polarmoment of inertia was explored, the formulas of shear stress were deduced, and thetorsional stiffness model of polygon shank was established, the contact pressureformula of taper and spindle have been deduced.The contact characteristics of polygon taper shank and spindle have beenstudied. According to the way of clamping, the model of the assembly betweenpolygon shank and spindle was established by UG software. Based on this model, thecontact stress’s changing effect impacted by tension force was analyzed and thedifferences of the equivalent stress between pyramid and non-pyramid was studiedby the AnsysWorkbench. By changing the angle tolerance of the shank and spindle,the assembly models of shank and spindle with different interference were got. Then an analysis on torsional stiffness and radial stiffness with different interference wasconducted.The experiment measuring the important parameters of polygon taper was done.The method using high-precision coordinate was adopted. A program measuring forPSK-63handle was made to analyze the polygon curve and taper parameters ofpolygon taper.This article provides a basic theory for manufacturing polygon taper anddeveloping the new high-speed tool system.