L10 calc help

[aldumoul]

Trying to figure this out from the NSK super precision catalog. Some values that I’ve been given by a colleague:

100 lb thrust
25 lb axial load, 4” from bearing set (15 degree angular contact…bearing 7011C) the bearing set is in DB
5000 RPM

Thanks!

 

[aldumoul]

Here is the bearing info

 

[tk90]

"Axial" and "thrust" are synonymous- are one of these actually radial loads (perpendicular to the shaft)?

Are you using a single bearing, or a pair in tandem?

 

[aldumoul]

I may have misspoke about the 25 lb load. So in the meantime, I would greatly appreciate help calculating the 100 lbs of thrust to start with. There are 2 sets of tandem bearings (in DB), the first set is subject to 100 lbs of thrust, which is more load bearing. If someone could show me how they arrived at the answer, that’d be awesome! Just started this position a month ago (spindle design). Before this, I worked in tool and die design my whole career.

Thanks!
Alan

 

[Tmoose]

Is this a grinding spindle ?
A new design?
Belt driven or ??
Grease lubricated ? the grease life can be shorter than the bearing life in very high speed spindles.

Only one pair can be fixed axially. The other pair must be able to float axially for thermal expansion ( although with a ~.0001" OD fit)
Alternatively especially in belt drive spindles a roller bearing is often used at the drive end for their greate adial capacity.

https://www.schaeffler.com/remoteme...ffler_2/catalogue_1/downloads_6/sp1_de_en.pdf

equivalent load calculations appear in most decent bearing catalogs and tech literature.

Spindle angular contact ball bearings just have slightly different contact angles ( typically 15 and 25°) than industrial ang cont brgs (40°).

 

[aldumoul]

It is a new spindle, not belt driven[pre][/pre]. Not sure what the application is (a senior engineer assigned me this so I can familiarize myself with how to arrive at the correct result). One set is fixed - these are the bearings I’m trying to calculate the L10 life for. The other set does float. We have a calculator to calculate grease life.

The equivalent load life calc is what I’m struggling with. The P value specifically. The 7011C (15 degree angular contact) bearings in tandem show some of the values needed to start calculating it (see attachment). And the other attachment shows a chart to input those values and take the calculation further. It just isn’t clear to me at this point.