How to repair the drive axle housing of a forklift?

The drive axle housing of the forklift is firmly installed on the forklift frame. Because the drive axle and the frame are rigidly connected, during the forklift's operations of picking up goods or handling and stacking, the drive axle will bear the majority of the weight. Moreover, there are also situations such as uneven roads and uneven loads on the fork frame. As a result, the drive axle will suffer from damages such as bending, breaking, wear of the bearing holes of the half shaft sleeves, and wear of the journal of the half shaft sleeves.

1. Inspection and repair of bent drive axle housing

Inspection of the bending of the drive axle housing. Before inspection, the flatness of the contact flange between the half shaft and the hub end plane should be corrected first to eliminate the end face circular runout error. Then, install the standard half shaft on the drive axle housing, tighten the bearings, and test the center positions of the left and right half shafts from inside the housing to determine if there is any bending. The difference between the two axes should not exceed 0.75mm.

2) When the drive axle housing is bent beyond the limit, it should be corrected. During correction, the corrected deformation should not exceed the original bending deformation, and the correction pressure should be maintained for a period of time to allow the bridge housing to undergo a certain plastic deformation. If the deformation is too large and the bending deformation is greater than 2mm, it can be corrected after preheating, but the heating temperature must not exceed 700℃. It is best to avoid heating correction for cast bridge housings.

2. Repair of broken drive axle housing

The cracks in the middle of the drive axle housing and on the flange can be repaired by welding. The key points of the operation are as follows:

1) Make a V-shaped bevel at 90° along the crack, with a depth of two-thirds of the thickness.

2) Drill holes with a diameter of 5mm at a distance of 6-10mm from each end of the crack.

3) For electric welding repair cracks, the weld layer should be higher than the base metal, but not exceed 1mm. After the front side is welded, carry out welding repair on the back side. After welding, the weld seam should be smoothed out. For welding repairs on the working plane, the flatness error should not exceed 0.25mm.

4) After the crack is welded and repaired, a reinforcing web plate should be welded at the crack location. Its thickness is generally 4 to 6mm, and the reinforcing web plate should be symmetrical to the center of the drive axle housing.

5) If the crack penetrates to the drive axle housing cover or the flange plane of the main reducer, a reinforcing web ring should be welded separately after welding repair. The reinforcing web ring of the drive axle housing cover plane can be re-attached to the outside, while the main reducer housing should be re-attached to the inner surface depending on the permission of the internal space. When welding the reinforcing web ring, it should first be tightly pressed onto a flat surface with bolts to prevent position movement and deflection during welding.

6) After welding and reinforcing, the drive axle housing should be re-inspected for its straightness error, the flatness error of the housing cover surface and the main reducer flange plane, and corrected and ground to meet the standards.

3. Inspection and repair of other parts

The coaxiality error of the inner and outer bearing housings at both ends of the bridge housing should not exceed 0.01mm. The perpendicularity error between the bearing housing neck and its thrust end face should not exceed 0.05mm. The neck of the bearing housing should be perpendicular to the flange plane of the brake base plate, and the verticality error should not exceed 0.1mm.

2) The thread damage of the screw hole should not exceed 2 turns. If it does, it can be repaired by inserting a screw sleeve or welding.

When the wear of the oil seal journal exceeds 0.15mm, it can be repaired by inserting a sleeve.

When the journal wear of the half shaft sleeve tubular rolling bearing exceeds 0.04mm, it can be repaired by chrome plating or surfacing welding.

5) When the half shaft sleeve has any kind of cracks or defects, it should be replaced.

6) The wear of the inner and outer end seat holes of the half shaft sleeve tube installed on the drive axle housing shall not exceed 0.06mm; otherwise, the journal of the half shaft sleeve tube can be chrome-plated or expanded to the repair size.

When the drive axle housing breaks, it should be replaced.