How to repair the drive axle housing of a forklift?

The drive axle housing of the forklift is firmly installed on the frame of the forklift. Since the drive axle and the frame are rigidly connected, during the operation of the forklift for loading goods or handling, stacking, etc., the drive axle will bear most of the weight. Moreover, there may be situations such as uneven road conditions and uneven load distribution on the frame, which will cause the drive axle to bend, fracture, wear out the bearing bush hole of the half-shaft sleeve and the shaft neck of the half-shaft sleeve, etc.

1. Inspection and repair of the drive axle housing bending

1) Inspection of the drive axle housing bending. Before inspection, the flatness of the contact flange at the end of the half-shaft and the hub should be corrected first, and the end face round runout error should be eliminated. Then, the standard half-shaft should be installed on the drive axle housing, the bearings should be tightened, and the center position of the left and right half-shafts should be tested from the housing to determine if there is any bending. The difference between the two axis lines should not exceed 0.75mm.

2) If the drive axle housing bending exceeds the limit, it should be corrected. During the correction, the deformation amount should not exceed the original bending deformation, and the correction pressure should be maintained for a period of time to allow the housing to undergo certain plastic deformation. If the deformation is too large and the bending deformation is greater than 2mm, preheating can be used for correction, but the heating temperature should not exceed 700℃. Cast drive axle housings are preferably avoided from being heated for correction.

2. Repair of the drive axle housing fracture

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

1) Make a 90° V-shaped groove along the crack, with a depth of 2/3 of the thickness.

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

3) Weld the crack, and the weld layer should be higher than the base metal, but not more than 1mm. After welding on the front side, perform welding on the reverse side, and the weld seam should be smoothed. The welding should be done on the working plane, and the plane error of the plane should not exceed 0.25mm.

4) After welding the crack, a reinforcing web should be welded at the crack, with a thickness generally of 4-6mm. The reinforcing web should be symmetrical to the center of the drive axle housing.

5) If the crack penetrates to the cover of the drive axle housing or the plane of the main reducer protrusion, an additional reinforcing ring should be welded after welding. The reinforcing ring on the plane of the cover of the drive axle housing can be reconnected to the outside, and the main reducer housing should be reconnected to the inside if the internal space permits. When welding the reinforcing ring, it should be first tightly pressed onto the plane with screws to avoid movement and bending during welding.

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

3. Inspection and repair of other parts

1) The coaxiality error of the inner and outer bearing seat necks at both ends of the bridge shell should not exceed 0.01mm; the verticality error of the bearing seat neck to its thrust end face should not exceed 0.05mm; the bearing seat neck should be perpendicular to the plane of the brake base plate protrusion, and the verticality error should not exceed 0.1mm.

2) The thread damage of the screw holes should not exceed 2 turns. If it exceeds, the screw sleeve repair or welding repair can be used.

3) When the wear of the shaft neck of the oil seal is greater than 0.15mm, it can be repaired by inserting a sleeve.

4) When the wear of the shaft neck of the half-shaft sleeve that installs rolling bearings is greater than 0.04mm, it can be repaired by chrome plating or welding.

5) Any cracks or defects in the half-shaft sleeve should be replaced.

6) The wear of the inner and outer end seat holes of the drive axle housing should not exceed 0.06mm. Otherwise, the shaft neck of the half-shaft sleeve can be chrome plated or enlarged to the repair size.