I have lubrication problem with ball bearings NU218 & 6218 made by FAG. they work on 2950r/min, max temperature is 70C. What type of grease should be used for those bearings?

Hi andja,

For the application you mentioned, an NLGI 2 lithium grease should be fine. That is granting that the shaft tolerance is as per specs. Oversized shaft might eat up all the radial internal clearance of the bearing and any type of grease will never work under this circumstances. I would suggest also to use C3 clearance bearing.

Cheers,
franko

Andja, although the speed limit for both these bearings is in the range of 3800 RPM for grease, I have been suggesting to my customers that they look at an SMA Air/Oil system from Dropsa. It has taken many applications and extended the life on these bearings by as much as 6 times over what they were getting.
If you dont want to change, I would suggest looking at your grease and running at least an EP1 in the same product that you are currently using. If you compare the two greases you will see that the base oil viscosity in both products should be the same, however the EP1 has less thickener so it will flow better. Although you may not be using an automated system, and the better pumpability is not an issue, you have to look at the fact that an EP2 may be causing viscous drag. It certainly won't harm anything to try the EP1, but it may help you.

Dean

You can try Castrol longtime PD2. http://www.castrol.com/castrol/productdetailmin.do?cate...25&contentId=6007436

Best regards,

Danny