| The tooth surface of spiral bevel gear is a complex three-dimensional surface.Its design calculation and adjustment are very complicated and the transmission quality control is difficult to achieve.In order to improve the meshing performance of spiral bevel gears and the stability of its operation,this paper proposed the modification method based on Ease-off with the pinion tooth surface completely conjugated gear tooth surface as the modification object.The discrete gear tooth surface data and the deviation data in this paper are calculated theoretically,therefore the discrete tooth contact analysis is used to achieve control of the transmission errors curve and the contact pattern.The concrete research contents are as follows:(1)According to the machine adjustment parameters of double-sided processing,the mathematical model of position vector and unit normal vector of pinion were established.Based on the gear meshing principle and the preset transmission relationship,and the pinion convex and concave tooth surface as the generating flank,the fully conjugated equations of gear tooth surfaces are derived and the corresponding3 D model is established.(2)M×N Mesh partition of rotary projection plane of completely conjugated gear tooth surface is completed.The mapping relation between the two-dimensional grid points of the rotating projection plane and the spatial gear tooth surface points is established.The coordinates of three-dimensional topological gear tooth surface of gear and pinion are obtained.On the basis of gear tooth surfaces as modified surfaces and the preset transmission relationship,four kinds of methods for constructing the deviation surface of Ease-off are put forward which could shelp control the contact area,transmission error and coincidence degree and this paper makes three kinds of analyses.On the basis of gear tooth surfaces as modified surfaces and the preset transmission relationship,four kinds of methods for constructing the deviation surface of Ease-off are put forward and they could be put into two categories.This method could help control the contact area,transmission error and coincidence degree.Discretize the Ease-off difference surface and make superposition with the 3D gear tooth surface and the modified surface of gear tooth is obtained.(3)Based on the principle of tooth contact analysis,we use step-by-step refinement of gear tooth surface,differential normal vector,double binary search,critical interference meshing and other methods and developed a discrete tooth contact analysis(DTCA)procedure.The meshing of two discrete tooth surfaces is simulated and the variables in the Ease-off surface representation are analyzed to complete the DTCA simulation(4)Enter the discrete points of pinion and gear’s modified tooth surface into the3 D software to complete the shape of the two gears complete the 3D contact simulation.Imported the 3D model into the finite element software Abaqus and completed the meshing and the array of gear tooth surface,and the secondary contact oval of the gear at the time of loading is obtained.The verification of the correctness of DTCA and tooth surface modification are obtained.(5)Prepared a numerical control program and discussed the principle of selecting cutting tool,machine processing strategy and post processor.Conducted simulation of the NC program in CIMCOEdit and Vericut to verify it.Made sure the machining program was correct before machining.After processing,the machining gear is measured to verify the correctness of the modified gear tooth surface.On the basis of the completely conjugated spiral bevel gear tooth surface,this paper designed the gear tooth surface and conducted precision forging of the model of the gear tooth surface.It provides a new idea for the design of gear tooth surface and the precision forging of tooth surface. |
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