At present, the main processing method of spiral bevel gear is cutting method, and its whole production process is: blank is obtained by forging method; Further rough and finish the prepared blank, install it on the workbench, and cut the teeth according to the forming method and generating method (this stage is an extremely key step, which directly affects the accuracy of the gear and the subsequent matching); After gear cutting, heat treatment, gear grinding and pairing are carried out, and finally the gear processing is completed.
With the rapid development of the machinery industry, there is not only a growing demand for gears, but also further requirements in terms of their varieties, specifications and costs. Researchers classified and divided gears according to the method of gear cutting.
At present, there are three methods for cutting and forming the tooth surface of spiral bevel gear, as shown in the table.
| Tooth cutting type | Characteristic | Advantages and disadvantages | Scope of use |
| Single side cutting method | During rough cutting, the tooth surfaces of large and small wheels are cut together, and during fine cutting, they are cut separately. The small wheel is cut according to the large wheel. | Low efficiency and poor contact area; The problem of insufficient number of machine tools and cutting tools is solved, and the investment cost is reduced. | It is suitable for single product or small-scale production. |
| Single cutting method | Use separate rough and fine cutting cutter heads to complete rough and fine cutting respectively. | The contact area and tooth surface have good finish; High production efficiency. | It is applicable to products with high quality requirements in small batch or medium batch. |
| Fixed installation method | It is consistent with the single cutting method, but each step of cutting must be processed on a specific machine tool. | The contact area and tooth surface have good finish and high production efficiency. However, the number of machine tools and types of cutterhead required increase the investment cost. | Suitable for mass production. |
| Semi rolling cutting method | It is the same as the fixed installation method, but the pinion wheel is processed by the expansion method and the large wheel is processed by the forming method. | The advantages and disadvantages are the same as the fixed installation method, but the efficiency of gear processing by forming method is improved. | It is suitable for mass production of gears with high modulus. |
| Spiral forming method | Different from the semi rolling cutting method, the cutter head has the characteristics of axial reciprocating motion when forming a large wheel. | Good meshing, smooth tooth surface and improved efficiency. | It is consistent with the half rolling method. |
| Double sided method | Large and small wheels are processed at the same time with double-sided cutter head. | High productivity, but it is difficult to control the contact area, resulting in poor forming quality. | It is suitable for mass and small modulus production. |
The machining and forming of spiral bevel gear has been very mature, but when using this method to process spiral bevel gear, there are some defects, such as complex tooth surface repair, difficult machine tool adjustment, long manufacturing cycle and poor interchangeability. It is easy to destroy the flow linearity of the metal surface of the gear during machining, which reduces the bending strength of the tooth root, the contact fatigue strength of the tooth surface and the service life of the gear.
Precision plastic forming technology can avoid these shortcomings, which is a new processing method to process spiral bevel gear that scholars at home and abroad have been looking for for for many years. From the existing research results, the problems existing in the research on the plastic forming technology of spiral bevel gear at home and abroad are as follows: the equipment investment required for ring rolling blank making is high, and the material utilization rate is not high; It is easy to concentrate the energy on the forming die, and the stress can not be all applied to the die. Therefore, the precision forming technology of spiral bevel gear is still in the research and development stage at home and abroad.