With the increase of transmission ratio, the pitch cone angle of the large wheel will increase. The risk of large wheel processing of hypoid gear is mainly the interference between one side of the cutter head and the surface cone of the large wheel. Therefore, it is necessary to limit the surface cone angle of the large wheel to no more than 85 degrees. When the cone angle of the large wheel surface is close to 85 degrees, pay attention to the inspection of the motion limit positions of the machine tool, cutter head and wheel blank during the gear cutting of the large hypoid gear, so as to avoid the interference between them.
In the test, the large wheel of hypoid gear with small number of teeth and large reduction ratio is processed by forming method (as shown in Figure 1). The existing gh-35 machine tool is used for processing parameter conversion, and the installation angle, eccentricity angle and bed position of the corresponding machine tool are adjusted. Since the surface cone angle of the hypoid gear is close to 85 °, it is necessary to pay attention to whether there is interference among the mechanisms of the machine tool, the cutter head and the wheel blank. This requires special attention when setting the knife.
The adjustment and processing process of the machine tool are roughly as follows:
1.Accurately adjust the inner and outer tool diameters of the cutter head, and control the tooth thickness of the hypoid gear by the tool top distance;
2.Adjust the installation angle of the wheel blank on the machine tool. The horizontal wheel position of the large hypoid gear is the sum of the installation distance of the wheel blank in the geometric design of the large wheel and the thickness of the washer used in the clamping of the large wheel;
3.Input the parameters such as shaking table angle during machining in the corresponding position in the NC window of the gear milling machine;
4.Determine the feed rate of the machined gear on the basis of the full tooth depth at the outer end of the hypoid gear;
5.After the first cutting of the hypoid gear wheel, measure the chord tooth height and chord tooth thickness of the cut tooth. Determine the feed rate according to the measured value.
The site of the machining process of hypoid gear wheel is shown in Figure 2.