1. Wheel reducer 2. Support shaft 3. Brake 4. Brake plate 5. Bridge shell 6. Main drive assembly 2 Welding scheme and process characteristics The first and second schemes of the same type of axle housing, support shaft and brake connecting plate 2a, b are welded by way of welding; Fig. 2c is the second type, the welding form with the brake connecting plate as the hole and the axle housing and the supporting shaft as the shaft Figure 2d is the third type, with the axle shell as the axis and the support shaft as the welded form of the hole. 1. axle housing 2. support shaft 3. brake connecting plate (a) First option (b) Second option (c) Third option (d) Fourth option In the first scheme and the second scheme, the axle shell is used as the hole, the support shaft is the shaft, and after the positioning, the fillet weld or the U-shaped weld is welded, and the brake connecting plate is welded to the axle shell by the fillet weld. The solution simplifies the complicated and cumbersome structure of the early drive axle housing, and makes the casting and forging simple structure, easy to cast, easy to process, and low in cost. The tight fit between the shaft and the hole improves the force condition of the bearing by the weld. The difference between the two solutions lies in the formation of the weld between the shaft and the weld between the holes. The former is a fillet weld welding form, and the processing process is simple; the latter is a U-shaped groove weld form, and the groove has a sufficient overlap surface for welding, the welding is firm, the penetration depth is large, and the welding efficiency is high. The welding area is small, which can avoid excessive heat loss and ensure the welding quality. The bearing capacity of the weld is much larger than that of the fillet weld. From the analysis of the welding process, the first solution is more reasonable than the second one. Therefore, the U-shaped groove is used for welding between the shaft and the hole in the other schemes. The third solution is that the axle housing and the support shaft are all shafts, and the U-shaped groove is respectively connected with the brake connecting plate. A tight fit between the shaft and the hole. The solution shaft and the hole are tightly matched. When assembled by thermal assembly, the brake connection plate is small in size, easy to heat, and easy to assemble. At the same time, however, the accuracy of the drive axle housing depends on three parts, which inevitably increases the cumulative error. To achieve the same accuracy, it is necessary to improve the machining accuracy of the parts. It carries two welds and connects three parts. The processing is complicated, the cost is high, the stress condition is not good, and the bearing capacity is weakened. Defective to the weld between the brake connection plate and the bridge. In the fourth solution, the support shaft is a hole, the axle housing is a shaft, and the U-shaped weld is connected, and the brake disc is welded to the support shaft by a fillet weld. The scheme has the advantages of the first scheme, and has no disadvantages in the structure and process of the third scheme, and is an ideal solution. Thus, the first and fourth are preferred. Guangzhou Jointair Co., Ltd. , https://www.jointair.cn