The reason why lead is selected as the blank of spiral bevel gear is that the recrystallization temperature of lead is – 14 ℃, lower than 0 ℃, its room temperature deformation is thermal deformation, and the deformation characteristic curve is similar to that of steel. Therefore, it is of certain significance to simulate the thermal deformation of steel by the deformation of lead at room temperature.
Most of the lead sold in the market is lead block or lead rod. The spiral bevel gear blank required for experimental research in this paper is a conical blank with cylindrical inner hole. The specification of the inner and outer diameter of the spiral bevel gear blank is difficult to find in the market, and the melting point of lead is 328 ℃, which can be melted in a heating container. Therefore, we use the casting method to cast the preform. According to the structure of spiral bevel gear blank, the casting structure model shown in figure 5.6A is designed. According to the designed part structure, it is directly turned by lathe (as shown in figure 5.6b).
The casting process of preform is shown in Figure 5.7. The first step is to put the lead into the crucible and put it together in the heating furnace, adjust the temperature of the heating furnace, set constant temperature 350 degrees, and melt it by heating. The second part is to take the melted lead water out of the heating furnace and cast it directly into the casting; The third part is to take out the cast spiral bevel gear blank after the lead water in the casting is cooled and formed, weigh the weight of the spiral bevel gear blank, and grind the spiral bevel gear blank to achieve the preform required for the test. Under the condition of ensuring the same volume of preforms, experimental research is carried out to verify the accuracy of numerical simulation results.