| The spiral bevel gear transmission system has been widely used in many fields such as transportation and equipment manufacturing due to its stable operation and high bearing capacity.Spiral bevel gears are the key components in the equipment.Due to the high requirements for their accuracy,reliability and other indicators,CNC grinding is usually required as the final finishing process.However,due to the complexity of the spiral bevel gear tooth surface and its grinding forming movement,and the large linear speed of the grinding wheel,it is easy to cause the workpiece temperature to be too high during the grinding process,and may further cause defects such as tooth surface burns.Therefore,in view of the above problems,this paper studies the grinding temperature field in the grinding process of spiral bevel gears,and proposes a calculation method for the grinding temperature field of spiral bevel gears,so as to realize the temperature prediction of the grinding process and provide the basis for the improvement of the grinding process.Based on the idea of combining analytical and numerical methods,this paper studies the calculation method of grinding temperature field of spiral bevel gears by using gear geometry theory,metal cutting theory and partial differential equation numerical solution.Firstly,the contact area of the grinding process is searched based on the gear meshing theory.Then,based on the idea of slice method,the three-dimensional contact area is discretized,and the heat flux density calcula,tion method is developed by using the two-dimensional grinding heat generation model.Furthermore,the temperature field method in the grinding process is developed by using the finite element method.Finally,based on the calculation method of grinding temperature field in this paper,the influence of different process parameters on the temperature field of spiral bevel gear grinding process is analyzed.The specific research contents are as follows :(1)According to the principle of spiral bevel gear grinding,the processing movement of grinding wheel and workpiece is analyzed.The grinding wheel geometry based on the generation method and the grinding wheel geometry based on the forming method are determined.According to the special situation of the forming method,the movement of the grinding wheel and the workpiece with the Waguli mechanism is analyzed.(2)According to the principle of gear meshing,the tooth surface equation of spiral bevel gear is derived(),and the range of tooth surface is determined.The tooth surface scatter diagram is obtained by discretization,and the tooth surface modeling of spiral bevel gear is completed.Based on the obtained tooth surface equation,the relevant geometric and motion parameters near any meshing point are obtained by using Baxter formula.(3)For generating spiral bevel gear,the distribution of grinding contact area at any point on the instantaneous contact line of spiral bevel gear grinding is determined by using the fitting surface theory,and the grinding contact arc length is obtained according to the different grinding depth.For the forming method to process spiral bevel gears,according to the motion trajectory of the Wagu force mechanism,the grinding depth of each grinding contact during the machining process is determined,and the grinding conditions of the grinding contact area at different times are obtained.(4)Based on the grinding principle,the plane grinding force model is established.The grinding force in the process of generating method and forming method is calculated respectively.Based on Jaeger moving heat source combined with triangular heat source distribution,the heat source distribution and heat flux density of spiral bevel gear grinding are obtained according to the heat distribution ratio.(5)Based on the theory of heat transfer,the distribution of temperature field in the whole process of spiral bevel gear is calculated by finite element method.The burn area is determined according to the calculation results and the critical value of burn.The accuracy of the model is proved by comparing with the literature.The influence of grinding depth,grinding speed and feed speed on grinding temperature field is studied. |
