Research On The Precision Analysis Of Spiral Bevel And Hypoid Gear On-line Measurement

With the development of the gear processing technology in recent years, the spiral bevel and hypoid gears is the basic components in power transmission system of modern machinery and its application scope is ever-widening. Presently the tooth surface measurement of the spiral bevel and hypoid gear has evolved from the traditional contact precision control to the tooth surface geometrical precision control. Though foreign inspection technology is more mature, its price is very high, especially the technique is no open with secrecy. And the domestic research started later and updated more slowly than abroad. Therefore, the research on measurement on-line and precision of the spiral bevel and hypoid gear is very important for improving our country gear product quality and competitive power in international marketplace.Meshing theory and processing principle of the spiral bevel and hypoid gears has been researched deeply based on the space surface knowledge in this paper. According to kinematics and coordinate transformation theory, the mathematical model of theoretical tooth surface in the workpiece coordinate system is established by the basic parameters of the spiral bevel and hypoid gear and the processing parameters of machine. And the model is the theory proof of both the error analysis and precision assessment. The theoretical tooth surface is reconstructed through NURBS according to coordinate data of limited the theoretical tooth and the reconstruction error is analyzed. It proves that using the method of NURBS to reconstruct spiral bevel gear tooth surface is correct and feasible.In the process of practical measurement, the advantages and disadvantages of two-dimensional and three-dimensional test head radius compensation method are contrasted and analyzed for the characteristics and requirement of spiral bevel and hypoid gear on-line measurement. B-spline surface fitting compensation method is used and the program of compensation algorithm is compiled used by VC++programming language. The compensation of spiral bevel and hypoid gear tooth surface measure point is realized. According to the knowledge of surface matching, compensated actual tooth surface is matched with theoretical tooth surface and the purpose of detection is achieved. Through the understanding of the spiral bevel gear drive requirements, with reference to the accuracy standards of spiral bevel gear existed at home and abroad, and taking into account the actual testing conditions, the precision evaluation index of spiral bevel gears is determined. The testing method of accuracy index is introduced to complete the index test of the evaluation of spiral bevel gears and the assessment of the actual processing accuracy grade of the spiral bevel gear.