Bearing race wear issue
Thread Content
For high-temperature oil pumps, at the NU314EM bearing, the inner ring often slips relative to the shaft. What could be the reason? Please share your analyses!
Come and learn*, looking forward to the hero’s reply! ! ! !
The clearance between the inner ring and the shaft is too large. Damage to the bearing increases rotational resistance.
The bearing in the inner ring has a tight fit with the shaft; its hardness is not sufficient!
The rough tolerance for 70 should be 0--+0.025; use a micrometer to measure it
The runout indicates that the amount of interference is insufficient. The shaft needs to be replaced. If the shaft is not original but is manufactured through machining, it is necessary to define the outer diameter of the shaft based on the dimensions of the bearing inner ring; once the tolerance ranges are determined, the shaft can be machined.
It is likely due to insufficient interference fit of the shaft. Since it is a high-temperature pump, as mentioned by the original poster, the bearings near the impeller may experience slightly higher temperatures due to heat radiation, seal leakage, and other factors. As a result, the interference fit of the pump shaft becomes insufficient when the temperature rises, which leads to this situation occurring from time to time.
The interference amount is insufficient. The shaft needs to be replaced.