Welding scheme and design of drive axle housing

[Abstract ] Through the comparative analysis of several welded structures and joints of the wheel loader drive axle housing, the stress distribution and calculation of the driving axle stress state are introduced, and the reasonable design of the components is discussed to determine the drive axle housing. Optimal design.

The drive axle is one of the key components of the wheel loader drive system, and the axle housing is the most critical component of the drive axle.

1 Early drive axle housing structure

The structure of the early loader drive transport bridge is shown in Figure 1. The axle housing 5 and the support shaft 2 are connected by bolts, and the axle flange of the axle housing is also a connecting plate, and a service brake is installed. The axle housing and the support shaft have a large weight and a large processing amount due to the large flange, and thus the processing cost is high. The bridge shell casting is at the intersection of the flange and the circular section. Because the wall thickness is not uniform, the cooling and solidification speed of the molten metal is inconsistent, and the large dust at both ends hinders the free shrinkage of the shell, which helps to form casting defects in the overfilled corner. Greatly affect the strength of the axle housing. There are instances of breaks from there during use. Due to structural and usage restrictions, casting defects cannot be fundamentally solved, resulting in unstable quality. Therefore, according to the rational design principle of the parts, for components with abrupt cross-sectional dimensions or complex shapes, try to use simple combination or welding.

1. Wheel side reduction non-speed device 2. Support shaft 3. Brake 4. Brake coupling plate 5. Bridge housing 6. Main transmission 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 connection plate
(a) First option (b) Second option? 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 scheme simplifies the complicated and cumbersome structure of the early drive axle housing of our factory, which 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 scheme (Fig. 2c) is that the axle housing and the support shaft are both shafts, and the U-shaped groove is respectively connected to 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.

The fourth solution (Fig. 2d) has a support shaft as a hole, a bridge shell as a shaft, and a U-shaped weld joint, 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.

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