The overhead EOT crane active wheel and the speed reducer of the crane are running frequently, and many times of reverse and stop will cause the torque and vibration of the shaft of the reducer to increase, which is easy to cause leakage. The occurrence of such problems, the traditional method to repair machining or welding plating, but both have certain disadvantages: the thermal stress generated by welding and high temperature can not be completely eliminated, prone to bending or fracture; and brush plating limited by the thickness of coating, easy peeling, and the two methods above are repairing metal with metal, can not change the relationship of “hard to fit hard”, in the comprehensive function of the force, will cause wear again.  The latest maintenance methods is mainly use polymer composite materials, which has strong adhesion, and excellent compressive strength performance. Application of polymer materials to repair, not only no welding thermal stress effect, the thickness of repair is not restricted, but also concession which metal products do not have, can absorb shock and vibration equipment, to avoid wear, and greatly prolong the service life of equipment components, save a lot of downtime for enterprises, create the huge economic value.

keywords:electric hoist electric hoist