| The spiral bevel gears are widely used in the mechanical transmission systems of aviation and motor industry.It has the most complex form and the most extensive application,so it is particularly suit the automobile industry of mass production,it is widely applied in axle gear transmission of various kinds of light and heavy trucks and SUVs in Europe and United States,Its design,processing and transmission quality are still a hot topic in the Mechanical transmission field.Because of the highly complexity of the spiral bevel gears,there are some defects and shortcomings in terms of design and manufacture.This seriously restricts the improvement of China’s independent design and manufacture and process improvement.This paper aims on the low accuracy of the modern digital gear tooth surface and the previous shortcomings,based on the theory of Non-Uniform Rational B-Splines,put forward a digital gear tooth surface reconstruction of the hypoid bevel gear.Then come up with the research of-the digital real tooth surface meshing characteristics,This can reflect the contact pattern and transmission error of the real aviation spiral bevel gears,and reflect the actual and theoretical tooth surfaces’ differences in meshing quality digitized.Through the study of this paper,realized the high precision of NURBS surface reconstruction,finished the hypoid gear real tooth surface digital inspection based on NURBS surface.It has laid a foundation for the standardization of quality inspection,for the realization of the digitalization and informatization of gear manufacturing aviation,automobile industry.The main researches of this paper can be summarized as the following:(1)By comparing the gear forming,generating method for processing,pinion round knife method,modified method processing.finished the wheel blank design of gear and pinion of the hypoid bevel gears.Then through the mathematical model of cutting tool,The tooth surface equation of gear and pinion is derived,get the tooth pastry coordinates by using MATLAB programming,finished the three-dimensional modeling of gear and pinion.(2)Completed the design method of NURBS surface and research.First of all,through the further perfect of forefathers’ research,consummate the design of the NURBS three times curve and the double three times NURBS surface.Then realized the digital tooth surface through a given tooth pastry coordinates on hypoid bevel gear.At last,by analyzing the absolute error,the fitting error is not greater than 0.1 um,meet the requirement of aviation,mechanical use,so we can use the digital surface instead of the tooth surface measurement for quality inspection analysis.(3)Carried out the actual tooth surface measurement and data processing.First,through the tooth surface measurement path planning,size,installation location,completed the three coordinate measuring actual tooth surface on gear measuring center.Then got the NURBS fitting gear and pinion.At last,output the digital gear by using NURBS surface IGES format.(4)Completed the real tooth surface meshing simulation and tooth surface contact research.First,finished the assembly of the theory gear pair and real gear pair.Then completed the solution of the theoretical tooth surface contact area,get the contact trace and transmission error and simulate the contact area by UG.At last,finished the numerical gear tooth surface contact analysis and simulate the contact area by considering the method of vector and non considering the method of vector.(5)Made the rolling test by Y955 for the concave side and convex side of the gear.The results show that the contact analysis of digital real tooth surface can be used to replace the traditional method.It provides an effective way for the digitalization and standardization of the meshing quality of hypoid gears. |
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