FicWad

that short summary shall show you pros and cons of ball bearings.
Sealing and Bearing are different from so called open and shielded bearing. There you can’t relubricate them after lubrication has leaked and broken out.
In this thread I will show you also where you can get good seal ball bearing for cheap price.
Also that leads to shorter durance of life compared with adequate maintained open or shielded bearing if used the right way, sealed bearings do have multiple advantages over other kinds of bearings.
Advantages
Absolutely no maintenance
Correctly ball bearings: you have to lubricate bearings in correct intervals.
To prevent failure: lubrication is very important.
On the other hand bearings sealed don’t require regular lubrication.


Users shouldn’t lubricate them at other times.
"ttv gmbh":http://www.ttv-gmbh.de/dichtungstechnik/ It doesn’t matter where you apply bearings this feature will save labor but those are even more suitable when bearing is situated in parts which aren’t accessible.
Those unsealed placed in the not easy reached areas of seal will have the need to the user to partially disassemble surroundings parts to make the maintenance.
Absolutely zero contaminants
Contaminants increase chances of wear and tear added to drastically decreasing lifetime of parts of machine.
Routes in those not sealed bearings which do allow for addition of a lubricant also allow the entrance of contaminants.
The sealed bearings have no entrances for contaminants because the seal is in normal case intact. seal which is keeping the lubricant inside also prevents the entry of contaminants.
Also this failure of that seal could also have the result in bearing’s not working anymore.
Zero chances of Over-Lubrication

By sealed bearings you shall not expect those accidental over-lubrication.

With seal bearings you won’t expect some accidental over-lubrication. But also those unsealed bearing fail quite often due to over-lubrication as compared with under-lubrication.
Most benefit from sealed bearing a user never should install grease fitting on those bearings or try to force grease into them.
By Marking the gadget correctly will ensure that the technical persons who do work on it will not try to lubricate the sealed bearings.
Contact or non-contact
The contact seals do touch inner track or inner race on which ball bearings are spinning.
This is helping preventing entry of moisture but also results in faster wear and tear and higher levels of operating temperatures.
But also the non-contact bearing seals don’t touch the inner races. As result their running temperature is in regular cases lower and with lower friction but don’t exclude moisture effectively from the bearing.

The popularity of sealed bearings have grown due to its high usage in some gadgets like autos, power tools and white goods. The bearing seals are important in stopping grease lubrication used in the form of bearings.