Tooth Surface Developable Principle And Line Contact Machining Simulation Of Helical Face Gear

The face gear mechanism has unique structure and performance advantages.Some bevel gear mechanisms have been gradually replaced by face gear mechanisms in foreign countries,which not only can simplify the installation and reduce the volume of the transmission mechanism,but also can improve the reliability of the transmission system.In order to expand the application advantages of face gear in the field of transmission,this paper takes the helical face gear as the research object,establishes a numerical model of the helical face gear tooth surface,and studies the gear shaping method of the helical face gear,based on the research on the tooth profile and surface of conventional helical face gear,a new developable ruled surface helical face gear is proposed,and studies the method of machining the developable ruled surface helical face gear by line contact with a cone face tool.The main research contents and corresponding results of this paper are as follows:(1)The tooth surface equation of the helical gear shaper is established.Based on combining the principle of gear meshing,the derivation of the helical face gear tooth surface equation is completed.The working tooth width of the helical face gear is determined by the limiting conditions of undercutting the tooth root and sharpening of the tooth tip of the helical face gear tooth,the influence of helical angle and transmission ratio on the tooth width of helical face gear is studied.The numerical example shows that the tooth width of the helical face gear increase with the increase of the transmission ratio;without considering the direction of rotation,the tooth width of the helical face gear decreases with the increase of the helical angle.The helical face gear tooth surface points are discretized by MATLAB,and the numerical modeling of the helical face gear tooth surface is completed.(2)The helical tool for gear shaping to process helical face gear is designed.By analyzing the motion required by the helical tool to process helical face gear,a five-axis CNC gear shaping machine model for processing helical face gear is designed,and a five-axis CNC gear shaping machine tool is established.The coordinate transformation system is used to deduce the numerical control motion law of the helical tool.A gear shaping simulation machine tool model is established in VERICUT,and different tool indexing angles and tool axial feed step lengths are used to simulate the gear shaping processing of the helical face gear.In the processing of gear shaping simulation,the smaller the tool indexing angle,the smaller the tool axial feed step,and the smaller the tooth surface deviation in gear shaping simulation processing.(3)By setting specific constraints,the point on the tooth top line of the face gear,on the tooth root line of the face gear and on the ridge line of the face gear,a space line clusters are constructed on the tooth surface of the helical face gear.Based on the analysis of the tooth surface of conventional helical face gear,a new developable ruled helical face gear is proposed,and a correction method is proposed for the developable ruled surface.Numerical analysis of developable ruled surface and conventional helical face gear tooth surface is carried out.The results show that the deviation between the two is a microscopic quantity,and the developable ruled surface can be used to replace the conventional helical face gear tooth surface.(4)According to the characteristics of the developable ruled surface,the geometric parameters of the tapered tool for line contact machining of the developable ruled surface helical face gear are designed.According to the motion required by the tapered cutter to mill the developable ruled surface,a five-axis CNC milling machine model is designed.The numerical control motion law of conical cutter milling face gear is deduced.Using conical cutters with different diameters,the line contact machining simulation of developable ruled surface helical face gear is completed in VERICUT.The results of the tooth surface deviation of the developable ruled surface helical face gear simulation show that the smaller the diameter of the conical surface tool is,the smaller the deviation between the simulated machining tooth surface and the developable ruled surface helical face gear tooth surface.