When the thickness of spur bevel gear blank is 90mm, the z-direction displacement nephogram of spur bevel gear blank with two different processing methods is shown in Figure 1. It can be seen from the figure that after the two processing methods are used, the straight bevel gear blank bends downward along the negative direction of the z-axis. The dark blue area in the figure indicates the maximum deformation in the middle of the straight bevel gear blank. After the processing, the maximum Z-direction displacement in the middle of the straight bevel gear blank is 0.098mm.
According to the previous analysis of the stiffness evolution of spur bevel gear blank during gear cutting, no matter which processing method is adopted, the stiffness of spur bevel gear blank decreases the fastest when machining the tooth groove in the middle of spur bevel gear blank. The closer the processing position is to the middle of spur bevel gear blank, the faster the stiffness of spur bevel gear blank decreases. It can be seen from Fig. 1 that when machining in mode 1, the maximum deformation of the first two cogged wheel blanks is only 0.03mm. When the gear cutting machining is carried out to the middle of the straight bevel gear blank, the deformation suddenly increases to 0.078mm; When processing in mode 2, first process the tooth groove in the middle of the straight bevel gear blank. At this time, the deformation of the straight bevel gear blank reaches 0.048mm. When the right half of the gear is processed, the deformation in the Z direction only reaches 0.069mm. From this, it can be inferred that when the stiffness decrease speed of spur bevel gear blank increases, the deformation speed of gear blank in Z direction also increases.
When the thickness of spur bevel gear blank is 85mm, the z-direction displacement nephogram of spur bevel gear blank with two different processing methods is shown in Figure 2. It can be seen from the figure that after reducing the thickness of the wheel blank, the z-direction deformation form of the split wheel blank is the same as that of the previous 90mm thick wheel blank. The growth rate of the deformation of the straight bevel gear blank is consistent with the change trend of the corresponding stiffness decline rate, but the displacement in the z-direction is increased compared with the previous straight bevel gear blank. The finite element simulation results show that the maximum negative displacement in Z direction of the split wheel blank of spur bevel gear with two machining methods is 0.117mm.
Through the results of finite element analysis of spur bevel gear blanks with thickness of 90mm and 85mm, it can be inferred that when only the thickness of spur bevel gear blank is changed, the deformation form of spur bevel gear blank in Z direction will not change, but the displacement value of spur bevel gear blank in Z direction will change.
When the straight bevel gear is processed in different Z direction, the straight bevel gear is divided into three ways, as shown in the figure 3. It can be seen from the figure that the deformation of the straight bevel gear blank divided by the two processing methods is the same, and the maximum displacement of the middle position of the straight bevel gear blank is 0.142mm. Therefore, it can be judged that the displacement in Z direction of spur bevel gear blank caused by the two processing methods is the same.
When the thickness of straight bevel gear blank is 75mm and 70mm, the displacement nephogram in Z direction after the processing of straight bevel gear blank is shown in Figure 4. It can be seen from the figure that the maximum negative displacement in Z direction in the middle of 75mm thick spur bevel gear blank is 0.173mm; The maximum negative displacement in Z direction in the middle of 70mm thick spur bevel gear blank is 0.227mm.
The deformation of the above five kinds of split gears with different thicknesses along the length is drawn into an image, as shown in Figure 5. It can be seen from the figure that the displacement in the Z direction of the spur bevel gear blank increases with the decrease of the blank thickness. The thickness difference between the five kinds of spur bevel gear blanks is 5mm, but the difference between the corresponding deformation of spur bevel gear blanks with different thicknesses gradually increases with the decrease of the spur bevel gear blank thickness, When the thickness of spur bevel gear blank is less than 80mm, the increasing speed of Z-direction deformation of split spur bevel gear becomes faster obviously.
