Bearing Damage – in Transport?

I recently had a client conversation about bearings getting damaged in transport. This can happen to new bearings during shopping, or after the bearing is installed. There was some confusion about shock loads causing “wear” on bearings.

Just to clarify, shock loads on bearings don’t cause “wear” per se. If the shock is great enough, rollers may indent raceways, causing permanent plastic deformation(s) that are readily identifiable as true brinelling (true “denting”.) The damage usually shows up strongly on any subsequent vibration results. If the machine is installed and operated, this damage may lead to multiple spalling sites on bearing raceways, generally at rolling element spacing. The life expectancy of the bearings may be only days to weeks in severe cases.

If the vibration is severe enough over time, false brinelling (false “dents”) in the bearing may occur. This takes time and vibration from an external source, very unlikely to occur during transport.

It’s possible to actually fracture bearing rings or rollers, or bend bearing components like cages, but this would be an extreme shock load.

I also recently observed a large Spherical Roller Thrust Bearing (maybe 24″ OD) that had to be scrapped while I was present at a motor shop. The shop folks opened the shipping box, rigged the bearing inner ring and roller set for lifting, and lifted the assembly about six feet. Then, the rollers came loose, dropped and impacted the housing washer in the box below. The true brinell marks were so severe the bearing had to be condemned. It may be possible to rework the bearing at the factory, but I didn’t follow up. Whether the cage had been damaged or dislodged during transport was a moot point after the rollers fell. The shop didn’t fully inspect before lifting, so they couldn’t recover damages and had to eat the cost. A tough less to learn.

Some would ask us to provide better packaging, but no one except the Aerospace Industry will pay for it. For Aerospace bearings, the packaging by itself often costs twice what a standard industrial quality bearing costs.

Find the original article here on SKF’s website 

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