How is the cause of copper bushing burnout related to shaft wear?

Worn shafts lead to burnt copper bushing

Increased coefficient of friction: When the shaft is worn, the roughness of its surface may increase. The coefficient of friction between the shaft and the copper bushing then increases, and during operation, more heat is generated by friction than under normal conditions. For example, if there are obvious scratches or wear pits on the surface of the shaft, these uneven parts will intensify the friction when moving relative to the copper bushing, making the local temperature rise rapidly.

Fit clearance change: shaft wear will make the fit clearance between the shaft and the copper bushing change. If the diameter of the shaft after wear becomes smaller, the clearance increases, the copper bushing in the process of operation will produce oscillation and vibration, resulting in uneven force on the copper bushing. This uneven force will make the copper bushing local wear increased, and in the oscillation process, the copper bushing and the relative movement between the shaft becomes more complex, the heat generated is more difficult to disseminate, easily caused by the copper bushing burned.

Lubrication state damage: under normal circumstances, the lubricant will form an oil film between the shaft and the copper bushing, play the role of lubrication and heat dissipation. After the shaft is worn, the wear particles on its surface may be mixed into the lubricant and contaminate the lubricant. These wear particles can damage the integrity of the oil film and make the lubrication of the lubricant less effective. At the same time, the wear particles may also act like an abrasive, further increasing the wear between the shaft and the copper bushing, generating more heat and ultimately leading to bushing burnout.

Burned bushings cause shaft wear

High temperatures affect the performance of shafts: Burnt copper bushings generate high temperatures, which are transferred to the shaft. When shafts are exposed to high temperatures, the mechanical properties of the material may change, such as a decrease in hardness. Furthermore, high temperatures can cause thermal expansion of the metal on the shaft surface, leading to further deterioration of the fit between the shaft and the copper bushing. When the hardness of the shaft is reduced, it is more likely to be worn during continued operation.

Damage to the copper bushing exacerbates shaft wear: After the copper bushing is burned, its internal structure may be damaged, and the surface may become rough or flake off. These damaged parts of the copper bushing will have a scraping and abrasive effect on the shaft. For example, copper shavings on the surface of the bushing may become embedded in the gap between the shaft and the bushing, continually grinding the surface of the shaft as it moves, thus increasing shaft wear.