The operation and maintenance of the differential of Komatsu CD825A-1 motor grader

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During operation, the lower shaft sleeve at the hinge part between the loader bucket and the boom will gradually wear out. Those with severe wear need to be replaced. When replacing the lower shaft sleeve, it is necessary to ensure the coaxiality of the four lower shaft sleeves. This is because the lower pin shaft of the bucket rotates around the center. If the coaxiality of the four lower shaft sleeves exceeds the tolerance, although the lower pin shaft can barely be hinged to the boom, during use, the lower pin shaft will often protrude from the lower shaft sleeve. To prevent the lower pin shaft from protruding, in the past, when replacing the lower shaft sleeve, four shaft sleeves were placed at the corresponding rib hole positions, and then a straight pipe with an inner diameter equivalent to that of the lower shaft sleeve was inserted into the four lower shaft sleeves. Then, the lower bushing and the ribs are welded, as shown in Figure 1. Even so, the lower pin shaft will still break from the flange position and protrude.

It was found in practice that the coaxiality of the lower bushing welded by the above-mentioned process method still exceeded the tolerance. For this reason, the replacement process of the lower shaft sleeve of the bucket has been improved.

Change the original cylindrical lower bushing to a shoulder structure. Change the straight pipe to a hollow shaft with a flange at one end and threads at the other. Add two tension sleeves and one adjusting bolt in the middle. The adjusting bolt is a double-ended bolt, with one end having a right-hand thread and the other end having a left-hand thread. The threads on the two tensioning sleeves are matched with the threads at both ends of the adjusting bolt. Each of the lower shaft sleeves on both sides is equipped with four bolt holes for fixing the lower pin shaft.

When replacing, the specific method is to insert the four processed lower shaft sleeves into the corresponding rib holes as shown in Figure 2. Combine the two tensioning sleeves with the adjusting bolts and position them as shown in the diagram. Pass the hollow shaft through the two lower shaft sleeves, the tensioning sleeve assembly and the other two lower shaft sleeves from the outside in sequence, and lock the hollow shaft with a lock nut. Turn the adjusting bolts to make the two tensioning sleeves press against the two lower shaft sleeves. Weld at the appropriate positions of the lower shaft sleeve and the rib. After cooling, remove the hollow shaft and tensioning sleeve assembly, and the replacement is complete.

After replacing the lower shaft sleeve of the bucket with the above-mentioned process, the coaxiality of the lower shaft sleeve meets the technical requirements, which can effectively prevent the lower pin shaft from protruding. This method is also very effective for replacing bushings with coaxiality requirements.