Study On The Machining Motion Conversion And Cutting Characteristics Of The Epicycloid Bevel Gear Based On The Six-axis Machine Tool

Being an efficient,stable and high-load transmission part,the epicycloid bevel gear is widely used in automobiles,ships,aircrafts and other equipment,and is in great need.As the traditional mechanical gear machining tool has the following characteristics such as its specificity,limited functions and complexity of processing settings,it will be gradually reduced,while the application of NC theory to achieve the advanced epicycloid bevel gear machining is the current trend in the development of intelligent manufacturing.In this paper,we use the TDNC-H8 CNC system developed to study the relationship of the gear-cutter movement,the cutting force and the cutting feedrate of the epicycloid bevel gear on the six-axis CNC machine tool.The main contents of this paper are as the following aspects:Firstly,the transformation of cutting kinematics.According to the principle of tooth forming of epicycloid bevel gear,the motion relation of each axis in epicycloid bevel gear cutting is analyzed,and the calculation method of cutting point is put forward based on unified equivalent transformation principle.By using VERICUT,the software is used to simulate the cutting code,and the process flow and program algorithm of cutting the tooth in the open CNC system are studied.And the cutting experiment is carried out on the six-axis machine tool.This study provides a convenient way to manufacture epicycloid bevel gears on universal six-axis CNC machine tools.Secondly,modeling the cutting force of epicycloid bevel gear.To solve the problem of large fluctuation of cutting force when machining the epicycloid bevel gear on universal six-axis machine tool,the cutting force model of gear format cutting method is studied.According to the geometrical principle of machining the epicycloid bevel gear and the hypothesis of reasonable cutting motion,the calculation method of chip thickness and chip width at arbitrary instant is deduced.A simplified model of dynamic milling force for gear format cutting is established The cutting force coefficient was calibrated by the machining experiment,and the instantaneous cutting force simulation program was designed.The effectiveness of the cutting force model is verified by the gear cutting force experiment.Last,cutting feed optimization of the epicycloid bevel gear.A variable feedrate control method which is based on constant cutting area of bevel gear is proposed,aiming to minimize the influence of constant feed force and cutting vibration on the six-axis machine tool.The method is based on the mathematical model of instantaneous cutting force of the epicycloid bevel gear on the cutting area variation law of the cutter blade under the constant feed speed.By using the particle swarm optimization algorithm,the feed rate of the cutter spindle is optimized,and compared with the constant feed cutting,it is proved that the variable feed cutting method has achieved the purpose of reducing the cutting force fluctuation and cutting vibration.The results of this paper provide the basis for the manufacture of epicycloid bevel gears on general CNC machine tools,and extend the space of general NC machine tools.