Constant-depth Tooth Spiral Bevel Gear Design And Machining Experiment

The spiral bevel gear with high strength, low noise and smooth transmission, is widely used in high speed and overloaded space intersecting shaft driving. According to the height along the length direction is consistent or not, the spiral bevel gear is divided into the tapered tooth and the constant-depth tooth. The tapered tooth is represented by Gleason design, which uses arc tooth profile. The constant-depth tooth is represented by Oerlikon and Klingelnberg design, which uses the extended epicycloid profile. In the processing of Oerlikon tooth, it’s continuous indexing, so the cutting efficiency and the index precision are high. In the using period, the constantdepth tooth has a certain advantage in noise control and driving stability. Therefore, the constant-depth tooth is gradually taken seriously in the domestic.Concerned the Oerlikon gear can’t be ground, the gear performance is limited to further improve. The Oerlikon’s machine, cutter and its corollary equipment are extremely expensive for general enterprise. In this paper, based on the Gleason tapered tooth design, the constant-depth was designed with the local synthesis and TCA(Tooth Contact Analysis). The constant-depth tooth adopted stub tooth and small knife dish, comparing the tapered tooth, the gear tooth’s strength was almost the same. The bias contact was eliminated fundamentally, so the standard contact area was easy to adjust. Only number 0 cutter was selected in milling process, so the process was very simple. The constant-depth tooth surface quality was improved, owning to the gear tooth could be ground. The small knife dish also reduced the rigid requirements of machine and improved the machining efficiency. In this paper, the main research contents and conclusions are as follows:1 Based on the Gleason spiral bevel gear, the geometry parameters, machining parameters and the cutter parameters of constant-depth tooth spiral bevel gear were researched. In the design, the tapered tooth’s surface cone angle and root cone angle were tilted in the big end, to make them parallel to the pitch cone, big end parameters remained unchanged. In order to avoid the small end tip excessive contraction, the system of stub teeth and small knife dish were adapted. Installed the blank with pitch cone in the milling process, the pitch cone pressure angle was consistent at inner side and outer side, and the bias is eliminated fundamentally.2 The machining parameters of constant-depth tooth spiral bevel gear were researched. Getting the machining parameters and choosing the tooth surface reference point, the reference point’s principal curvature and principal direction were calculated. With the local synthesis method and the TCA technology, the reference point’s second order contact parameters were adjusted and the gear’s contact performance were controlled effectively near the reference point, to get the pinion’s machining parameters in the end. According to the theory, organized the corresponding program, then the calculation of geometric parameters, machining parameters and TCA analysis were carried on.3 The constant-depth tooth spiral bevel gear’s three-dimensional accurate modeling technology was researched. According to the gear tooth surface equation and boundary conditions, organized the program to generate the file of tooth surface coordinates point matching UG software. The point coordinate files were imported to UG, establishing the constant-depth tooth spiral bevel gear and the tapered tooth’s 3D accurate model. Through motion simulation, the gear’s instantaneous contact area state were simulated, the TCA analysis result were verified, compared the differences two kinds of gear’s contact area. The tooth shape was analyzed.4 With finite element method, the two kinds of gear’s contact stress were researched. In ANSYS, the established models’ tooth contact stress was analyzed, to explore the size and distribution of the two kinds of gears’ tooth surface contact stress.5 The milling tooth experiment was finished with conventional Gleason machine. Designed and processed the constant-depth tooth blank and fixture. The constantdepth tooth spiral bevel gear fixed installation method’s processing parameters were got, which matched GH35 C milling tooth machine. The machining experiment was carried on. Rolling test was got on to adjust contact area, until to get the test sample with ideal contact area. The experiment results showed that the standard contact area was easy to adjust and the machining efficiency could be improved.