ACCORDING to Marlon Casey from the Rexnord Bearings Division, more than a quarter of all bearing failures are caused by installation and mounting errors.
While lubrication problems are still responsible for most bearing failures, installation errors are avoidable through proper training, correct procedures and informed selection of products and features.
Common problems with mounting and installation include insufficient tightness, defective shafts, misalignment, lack of expansion provisions and abusive handling.
If bearings are not correctly forced up its tapered adaptor sleeve, they can slip or turn on the shaft. On the other hand, over-tightening can reduce a bearing’s internal clearance and cause it to run hot.
Traditionally, it was time-consumer and difficult to determine the sufficient amount of tightness, but newer bearings have features to help an installer determine when they are properly tightened.
Shafts should be clean, round, straight and smooth. They should be checked for nicks, gouges and deep scratches. These areas should be filed until they are smooth. Where worn shafts are used, the bearing seat should be sanded to smooth out any ridges or burrs.
Misalignment between the shaft and the bearing can be caused by an imprecise mounting frame, shaft and housing support deflections. Most dynamically aligning rolling element bearings can compensate for this, but if the bearings are too misaligned, its internal components and seals can be damaged.
During the operation of equipment, the shaft can expand due to heat. This expansion should be compensated for by an allowance of axial clearance. If this allowance for heat expansion is not taken into account during selection, the bearing can fail prematurely when the internal clearance in the bearing is reduced to zero.
Importantly, during preparation and installation, dirt, water and metal chips should be kept off all parts. Hammer blows, external heat sources and the improper use of force can damage the bearing’s precision parts.
The bearing’s internal components should not be handled with bare hands because the acidic moisture on the hands can corrode the bearing’s exposed metal surfaces. It is also important to control lubrication and humidity.
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