Bearing Library: Troubleshooting of the main NSK bearing lubrication of the mill

The general main bearing operation failure mainly has the following situations:

1. The temperature of the lubricating oil gradually rises, and babbitt alloy streaks are formed on the outer surface of the hollow shaft journal. The deep streaks can reach about 2mm, and the density is uneven. The main reason is that the smoothness of the hollow shaft journal is not enough, so that the contact point of the tile surface is subjected to shear stress, which causes a large area of ​​strain (shear failure). The babbitt alloy particles are pasted on the surface of the hollow shaft journal, and when the hollow shaft is turned to the upper part, it meets with the cold lubricating oil and is cold treated, thereby increasing the hardness. When it is turned to the bottom with the hollow shaft, the tile surface is strained and appears Strip marks with unequal spacing. At the same time, the temperature of the lubricating oil of the main bearing gradually rises after the hollow shaft with babbitt alloy particles is cyclically rubbed, resulting in high temperature. At this time, the bearing bush should be pulled out, and the surface of the tile should be scratched again. If the streak is too deep, the homogeneous babbitt alloy should be repaired.
2. High temperature appears on one side of the bearing bush. This is caused by a small-area contact between the tile surface and the hollow shaft journal, which is caused by a larger static load due to a fault in the adjustment of the shoe seat. At this time, the barrel of the mill should be lifted up, and the contact between the spherical tile back and the tile seat should be checked. If necessary, the tile seat and tile back should be re-ground to make it aligning freely. At the same time, it is necessary to re-scrape the tile surface to completely scrape off the oxide layer, and polish the hollow shaft journal with a whetstone.
3. When the temperature rises, the main shaft is gloomy when there is t, and there is adhesion. This is caused by the local high temperature of the tile surface and the glue. At this time, the bearing bush should be scraped; sometimes the main shaft is bright, which is due to oil The oil should be changed due to poor quality and many impurities in the oil.
4. The oil temperature is high, but there is no babbitt alloy adhesion phenomenon. The reasons may be as follows: one is that the supply of lubricating oil is low and the viscosity is low, and the oil film cannot be formed; the other is that the oil quality is poor; the third is that the grinding bush does not meet the specification requirements, and the gap between the bushes is too small; the fourth is the bearing bush The cooling water is not smooth. Measures such as oil change, re-scraping and unblocked cooling water can be taken respectively.