Research On The Technological Basis Of Nc Machining Spherical Involute Tooth Surface

Spiral bevel gear is used to transmit the power between two intersecting or staggered shafts in space.It has the advantages of large coincidence,smooth transmission,low noise,high bearing capacity and high transmission efficiency;It is widely used in automobile industry,aerospace and navigation industry,mining machinery and other fields.The 13 th Five-Year Plan puts forward higher requirements for the stability of power transmission of spiral bevel gears in the automotive industry and the expansion of other engineering applications.The higher the machining accuracy of the spiral bevel gear’s tooth surfaces,the better the accuracy and stability of power transmission.The processing cost of special machine tool is high and foreign core technology is monopolized;Therefore,the use of general machine tools to improve the tooth surface accuracy of spiral bevel gear has become a research hotspot.The heat treatment and finishing process of the tooth surface after machining are also concerned;Based on the theory of spherical involute formation and wavelet theory and NURBS curves and surfaces;this paper studies on improving the machining accuracy of tooth surface,reducing the deformation of tooth surface after heat treatment and using electrochemical finishing to improve the "polygon effect" caused by CNC machining,so as to improve the smoothness of tooth surface.It is mainly divided into the following aspects:(1)According to the spherical involute equation and MATLAB programming,the discrete points data of tooth surface were obtained.The biorthogonal wavelet is used to process the discrete data of the tooth surface to reduce the complexity of the tooth surface and improve the smoothness of the tooth surface.Combined with accurate fitting of NURBS curve and surface to reduce the error in CNC machining process;Experimental results show that compared with the original tooth surface,the average machining errors on the concave and convex surface of the big wheel are reduced by 14.58μm and 14.62μm respectively by using biorthogonal wavelet,so the machining accuracy is improved compared with the original tooth surface,which proves that the proposed method is feasible.(2)By using different wavelets to process the data of the tooth surface,the heat treatment of the tooth surface after CNC machining is carried out,and the law of deformation of tooth surface after heat treatment by using different wavelet processing methods was explored.The experimental results show that compared with the orthogonal wavelet processing,the average deformation of the concave and convex surfaces of the large wheel is reduced by 5μm and 12μm by using biorthogonal wavelet processing.(3)In order to improve the problem of "polygon effect" in NC machining on the surface,the electrochemical finishing method is proposed;Using the method of profiling principle,the spherical cathode was used to imitate the shape of ball end milling cutter in NC machining,and the surface was finished.The results of simulation and experiment show that the electrochemical finishing can reduce the microscopic high point of the surface,and the peak tends to be arc,which improves the problem of "polygon effect",so the surface quality and smoothness are improved.