Gear Shaping Processing Technology Of Constant Cutting Force

Small module gear is the core part of precision reducer,but the domestic processing equipment can't meet the design requirements because of the low processing precision.Using the traditional gear shaping processing technology,the cutting force are constantly changing which engendering the vibration of the machining process,changing the original processing position and reduce the machining precision.In this paper,a disc slotting cutter was used as a tool for gear shaping,and the geometric shape and the influence of the rake face and the rear face on cutting edge were analyzed.By calculating the helix angle of the cutting edge,the polar equation of cutting edge on the end face of the cutter was deduced.The cutting edge profile on the end face of the cutter was accurately modeled in rectangular coordinate system according to the derived pressure angle modified formula and the minimum tooth number without undercut was calculated.Based on the theory of chip deformation,the reasons and main sources of cutting force were analyzed,and the cutting force calculating formula of orthogonal free cutting was deduced.Then,combined with the analysis of the structure of the cutter,a gear shaping model was proposed and the calculating formula of cutting force was derived.By using the least square method to fit the cutting force data obtained from the gear shaping experiment,the cutting model and the calculation formula were verified,the average error of cutting force fitting was 8% to 12%.According to the analysis of motion process and processing parameters of CNC gear shaper,the kinematics model of gear shaping process was established.The changing law of cutting area and chip shape was analyzed by simulating the cutting process of single tooth of the cutter.According to analysing the parameters of the traditional method,the calculating method of the cutting area was adjusted.The changing law of cutting area and the connection with the motion process in traditional method was obtained through the simulation.Then,the algorithm of constant cutting force method in gear shaping was proposed.Through the gear shaping test,in the process of using traditional method,the variation range of rough machining cutting force was up to 80% and the variation range of finishing machining cutting force was up to 40%.But in the process of using constant cutting force method,the variation range of rough machining cutting force was within 15% and the machining efficiency was increased by 14%,the variation range of finishing machining cutting force is within 18%,a single pitch error precision grade was improved from level 6 to level 5,pitch cumulative error precision grade was improved from level 5 to level 4,the radial run-out error precision grade was improved from level 7 to level 6.