Mechanism And Experimental Investigation On Material Flow In Gear Roll-Forming With Axial Infeed

As a new gear forming method,the gear roll-forming process with axial infeed can overcome the defects of cutting machining such as low material utilization rate and low fatigue life of teeth.It can also avoid the problems of extrusion,forging such as demoulding difficulty and low service life of die.It can satisfy the production requirement of high efficiency and precision.However,there is less research of domestic and international on gear rolling process with axial infeed.The mechanism of material flow is not clear and there is no scientific basis for the selection of process parameters.This process is far from industrial application.To solve these problems,this paper studies the flow of materials in plastic zone during roll-forming process based on the theory of slip line field,The influence of process parameters on the flow of materials was investigated by finite element analysis.The simulation results are verified by the gear roll-forming experiment.The following contents are studied:(1)The force of workpiece in roll-forming process with axial infeed was analyzed.The slip-line field of the plastic deformation zone was established by the graphical method.The material flow trend of different parts of workpiece is predicted by the theory of velocity field.The material flow state in the plastic deformation zone of the workpiece under different forming stages was analyzed.(2)Based on finite element method,simulation of the workpiece material flow process is carried out.Rotational motion of the workpiece is hard to be defined in software,thus a kinematic model,the workpiece rotation is replaced by the rolling tool revolution,is deduced.The correctness of the kinematic model is verified by the coordinate transformation theory.(3)The characteristics of the forming gear teeth were obtained by analyzing the change rule of tooth strain and node velocity in each stage.Based on the parameters of tooth strain,material flow velocity,effective tooth height and rabbit ear volume,The influence law of the feed speed,the roller rotate speed,the friction coefficient between roller and workpiece on the material flow is analyzed based on the control variable method.(4)The material flow rule is verified on the gear roll-forming experiment platform.To demonstrate the flow of materials clearly.The motion track of workpiece material was tracked by "grid method",and the deformation of the mesh is compared with the finite element results.