The Reconstruction And NC Machining Of The Tooth Surface Of Spiral Bevel Gears Based On NURBS And Wavelet

The development on the automobile industry and heavy load machinery makes the demand for spiral bevel gears increase a lot.At the same time,the improving on the performance index of the safety and stability of the vehicle leads to higher requirements for the machining accuracy and processing efficiency of spiral bevel gear.How to improve the machining accuracy and processing efficiency of spiral bevel gears has always been research hotspots.Researches on upgrading of processing equipment,correction in processing process and optimizations of tooth surface after processed have never stopped.At present,spiral bevel gears are manufactured with special equipment,which have inadequate interchangeability or without interchangeability and the core technology is monopolized by foreign countries.In this paper,based on the digital model of spiral bevel gear,the research on improving the precision of gear machining is carried out with the tool of universal numerical control milling machine.The main contents can be divided into the following aspects:(1)In order to compensate the design defect for the principle of conjugate surface and realizing the precise modeling of spiral bevel gear.The theory of spherical involute is used as the basis of tooth surface design,and the principle of cutting tooth is used as a reference for spiral line design.NURBS theory is used to fit the tooth surface,and the parametric design of gear is completed.A complete calculation program is written for the discrete points of spiral bevel gear tooth surface under the given parameters,and the three-dimensional digital model of spiral bevel gear is established.(2)The tooth surface optimization scheme based on the wavelet multi-resolution method is proposed,which can reduce the complexity of the tooth surface and improve the smoothness of the tooth surface on the premise of ensuring the tooth surface fitting precision by eliminated the high frequency information of the tooth surface control points.Digital model is developed for machining spiral bevel gears based on universal CNC machine tools.(3)The simulation processing of spiral bevel gear is carried out,the size of blank and the scheme of turning are designed.A reasonable processing scheme is designed for machining spiral bevel gears based on universal CNC machine tools by comparing and analyzed the influence of cutting tool size,driving method and cutting amount on tool path and machining allowance.(4)The relationship between circular arc difference compensation theory and curvature is analyzed.The machining verification of spiral bevel gear wheel is completed on three axis CNC milling machine.Three-coordinate measuring instrument is used to measure the tooth surface data,and the machining accuracy of tooth surface before and after optimization is compared and analyzed.It is proved that the wavelet optimization can effectively alleviate the phenomenon of machining over cutting and helps to improve the tooth surface machining precision...