Research On Cutting Force And Cutting Power Prediction For Gear Hobbing Based On Moving Frame

Gear as an important basic component,its manufacturing level is an important index to measure a country’s industrial level.Gear hobbing is an important rough and semi-finish machining process,and its machining quality directly affects the quality of the gears.With the development of intelligent CNC gear hobbing machine,how to realize real-time monitoring of the quantity that needs offline measurement,such as the wear status of the hob and the precision of the machined gear,by analyzing the current of the motor,torque and other signals collected during the gear hobbing process has become an important issue.In this paper,the cutting force and cutting power in gear hobbing process are studied by means of modeling simulation and experiment.Firstly,the parametric model of cylindrical gear hob was established,and the kinematic model of hobbing process was established according to the structure of six-axis CNC hobbing machine.On this basis,the trajectory equation of the cutting edge in the hobbing process was established.By means of the calculated cutting edge trajectory,the Solidworks software was used to create 3d geometric models of undeformed chips of rough rolling and fine rolling respectively.The material removal process in gear hobbing was simulated,and the geometric morphology of undeformed chips in rough hobbing and fine hobbing was compared and analyzed.At the same time,by means of the parametric model of hob and the cutting edge trajectory equation,the analytic equation of undeformed chip thickness was derived by introducing the movable frame method,which laid a foundation for the subsequent analysis and creation of cutting force and cutting power models in the process of hobbing.Secondly,the equation of resultant cutting speed of tool-blank synthesis during gear hobbing was deduced,and the formulas of working angles were further deduced on this basis.Combined with the undeformed chip model,a cutting force and cutting power model of single tooth during gear hobbing was established based on the oblique cutting model considering the change of working angles during machining process.In addition,this paper divided the cutting area and calculates the range of cutter teeth involved in cutting along the direction of the flute.The calculation method of cutting overlap coefficient is presented,which can be used as the criterion to determine whether there are more than one cutter teeth in the hob helical direction to cut the same tooth groove.The cutting force and cutting power models of the hob in the hobbing process were established on the basis of the number of the cutter teeth involved in the machining in the above two directions.Finally,the cutting power model is verified by hobbing experiments.The measuring principle of gear hobbing machine spindle motor power signal is studied,and the equipment for measuring spindle motor power is designed and built.Using this equipment,the power of spindle motor was measured when YKX3132M gear hobbing machine cut a certain type of gear in actual production,and the power signal variation rule of hob idling and hob under three cutting strokes was analyzed.The correctness of the model was verified by gear hobbing experiment.