Design Calculation for Wedge Cam of Small Roller Centering Three-Jaw Jig

Abstract

As wedge cam contour’s conventional equation of small roller centering three-jaw jig calculated by classic method is complex and difficult to be used for processing directly, a numerical calculation method for the wedge cam contour is proposed. Firstly, structure and working principle of centering small roller jig is introduced. Secondly, a new numerical calculation method sampling for wedge cam contour using equal step is presented, which can be obtained sampling points expression by numerical calculation model. Then,these samples points assignment will be fitting and interpolation in accordance with quadratic polynomial curve. The equation of quadratic polynomial interpolation on these sampling points these sampling will be obtained, which can be directly applied to NC programming. At last, through comparing fitted quadratic polynomial curve calculated by the numerical method with the theoretical curve calculated by classic method, it is found that the comparison tolerance is much smaller than conventional processing tolerance which is produced by using the theoretical curve for processing. The comparison tolerance is analyzed, refining the sampling step length and using piecewise fitting and interpolation loop calculation method is proposed,which can further improve numerical calculation accuracy to satisfy the requirement of higher and higher positioning. Therefore, it can be concluded that the numerical calculation method can effectively solve the difficult processing problem of wedge cam contour, which will produce better economic benefits.