Reasons and countermeasures for fatigue pitting corrosion in gear reducers

 Gear reducerThe fatigue pitting corrosion of gears occurs relatively late compared to early pitting corrosion, and starts with a smaller and shallower diameter. Once fatigue pitting corrosion occurs, it often develops quickly and ultimately leads to large-scale peeling, causing the gear to be scrapped. The reasons and countermeasures for fatigue pitting corrosion are as follows:

(1) The pitting corrosion caused by poor heat treatment of materials is often smooth, and the pitting corrosion caused by uneven heat treatment is often concentrated at a certain position of the gear. At this point, it is necessary to update the gears.

(2) Unauthorized increase in usage load resulted in fatigue pitting on the tooth surface. At this point, the usage load can be reduced.

(3) The selection of lubricating oil is unreasonable. Due to the low viscosity or failure of the lubricating oil used, an oil film cannot be formed between the tooth surfaces, resulting in direct contact and pitting corrosion. It is necessary to replace the lubricating oil with a reasonable one or increase the viscosity, which can quickly improve the pitting corrosion condition of the tooth surfaces.

(4) The excessive vibration of the gearbox transmission bearings can cause an increase in load. Due to the large clearance between the bearings and the bearing holes, as well as the stiffness of the transmission bearings, the shaft system can vibrate, resulting in an increase in load transmission to the gears and causing fatigue pitting on the tooth surface. At this point, replacing the transmission shaft with a higher stiffness and repairing the bearing clearance or reducing the lifting speed can be used to extend the service life of the gear.

(5) Poor installation of the gearbox in the lifting mechanism can cause local contact on the tooth surface, and the misalignment error of the gear axis during installation can lead to excessive local contact load on the tooth surface, resulting in fatigue pitting. At this time, the contact area of the tooth surface can be improved by adjusting the levelness of the body (adding copper or steel gaskets between the reducer body and the foundation or base), and the pitting condition of the tooth surface can also be improved by increasing the contact area through running in, grinding, and other means.

(6) Other factors can also cause fatigue pitting on the tooth surface. If the selection of tooth surface parameters is unreasonable, tooth tip interference, low viscosity in gear manufacturing, and excessive tooth surface roughness, these factors should be carefully analyzed, and specific problems should be analyzed and different measures should be taken to solve them.

No matter what kind of damage occurs to the gear teeth, it is just a phenomenon. The key is to analyze the cause of the damage through the phenomenon. Only by identifying the cause and the essence of the damage can corresponding measures be taken to ensure the expected service life of the gear from storage, use, and other aspects.