Failure Analysis and Causes of Overhead Cranes Reducers

The reducer is one of the main components of the overhead crane operating mechanism. Common reducers include worm gear reducers, planetary reducers and hard tooth surface reducers. Crane reducers are widely used in docks, construction, steel plants, and other construction industries that need to lift heavy objects. The following will introduce the failure analysis and reasons of the bridge crane reducer.

1. What role does the overhead crane reducer play in lifting machinery? What kinds of common reducers are there?

The overhead crane reducer is one of the main components of the overhead crane operating mechanism. Its main function is to convert the high speed of the motor operation into the actual speed required by the various mechanisms of the crane, and obtain a large torque, to lift the heavy objects smoothly. Common reducers include worm gear reducers, planetary reducers, and hard tooth surface reducers. Its models are ZQ type, Z H Q type, ZSC type, and so on.

2. What are the normal working conditions of the overhead crane reducer?

①No oil leakage is allowed at the joint surface of the housing and the bearing, and the connecting bolts cannot loosen.

② During operation, the gear meshing sound should be normal and stable, there should be no high and low noise and metal collision sound, and no jumping phenomenon is allowed. 

③ When a mechanism adopts two reducers that work equally, their specification and type should be the same from the same manufacturer. 

④ There should be a nameplate mark on the overhead crane reducer to prevent the wrong installation. For the reducer without a nameplate, the external dimensions and installation dimensions must be checked, and the installation can be carried out only after confirmation. 

⑤ The reducer housing has no defects such as cracks; the anchor bolts should be well tightened; 

⑥ The quality and quantity of lubricating oil used in the reducer should meet the requirements of the instruction manual. 

1. Failure analysis of overhead crane reducer 

The overhead crane reducer is an important transmission part of the bridge crane. It transmits the torque through gear meshing and adjusts the high-speed operation of the motor to the required speed. During the transmission of torque, the gears will have broken teeth, pitting on the tooth surface, and glue on the tooth surface. Mechanical faults such as wear and tooth surface wear, etc., the reasons for the failure of the gear are as follows: 

a. Fatigue fracture caused by short-time overload or impact load and repeated bending; 

b. The tooth surface is not smooth, there are raised points to cause stress concentration, or the lubricant is not clean; 

c. Lubrication failure due to excessive temperature; 

d. Wear due to the entry of hard particles into the friction surfaces. 

2. Precautions for overhead cranes: 

a. The crane cannot be loaded and used, and the starting and braking should be slow and stable. It is forbidden to suddenly reverse the car under non-specific circumstances;

b. It is necessary to replace the lubricant in time, clean the shell, and choose the appropriate type of lubricant;

c. Always check whether the lubricating oil is clean; if it is found that the lubricating oil is not clean, it should be replaced in time.

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