In view of the existing problems, it is proposed to carry out research in the following aspects:
(1) According to the geometric theory of spiral bevel gear machining by forming method, the calculation formulas of instantaneous undeformed chip thickness and chip width at any time are deduced, the dynamic milling force model of spiral bevel gear large wheel machining by forming method is established, the milling force coefficient is calibrated through orthogonal experiment, and the dynamic milling force simulation program of spiral bevel gear large wheel machining by forming method is compiled. In order to verify the effectiveness of the dynamic milling force model, it is necessary to design the experimental device and draw up the experimental scheme in detail.
(2) Based on the geometric principle and machine kinematics principle of four axis NC gear milling machine hobbing method for machining spiral bevel gear pinion, the calculation formula of instantaneous undeformed chip area of cutting layer in the process of rough milling spiral bevel gear pinion is deduced. Using the traditional cutting force model, the milling force model of spiral bevel gear pinion processed by hobbing method is established, and the milling force simulation program of spiral bevel gear pinion processed by NC gear milling machine hobbing method is compiled, And design the verification scheme.
(3) A variable feed rate control method under the constraint of basically constant instantaneous tangential cutting force is proposed. This method is based on the instantaneous cutting force model of spiral bevel gear machined by forming method. By changing the NC code feed speed of gear milling machine, the variable feed speed control is realized, so as to reduce the fluctuation of cutting force, reduce the vibration and abnormal noise in the process of NC gear milling, improve the quality and machining efficiency of NC gear milling, and prolong the service life of machining tools.
(4) An optimization scheme of rough milling parameters of spiral bevel gear hobbing method based on harmony search algorithm (HSA) is established. It takes the shortest process time (maximum productivity) and the lowest processing cost of a single piece as the objective function, the maximum allowable cutting speed, cutting power and tool durability of the blade as the constraints, and the actual cutting speed, moving speed of the linkage shaft and single-step interpolation degree as the optimization variables, The cutting parameter optimization model of NC Hobbing rough milling spiral bevel gear is established. The optimization program is written in MATLAB to obtain the best rough milling cutting parameters, and the effectiveness of the model is verified by an example.
(5) According to the machining principle of precision milling spiral bevel gear by NC Hobbing method, the analytical relationship between the average residual height of tooth surface and cutting parameters (cutting speed, moving speed of linkage shaft, single-step interpolation degree) is established, and the influence law of cutting parameters on the average residual height of tooth surface is analyzed and verified by experiments. A scheme which can predict the tooth surface roughness of spiral bevel gear is proposed.