L10 Bearing Life Calculator

[chris8189]

Hi,

I have been given an Excel Spreadsheet which performs the L10 bearing life calculation for a series of different bearings that our company uses. The task is to change the spreadsheet so that it uses ISO data, and NOT the Timken data that it currently uses for the calculation. However, I'm having trouble understanding what some of the variables are referring to, such as 'Kt', 'Nc', 'Fg' (see attached screenshot). These are not present in the Timken catalogue, and I'm having trouble finding out what they mean. Could somebody please help?

Many Thanks.

 

[Tmoose]

I think you need a better, older catalog. Maybe one whose paper pages' edges are starting to brown from the old days, with a thick engineering section.

This page found the definition of two of those variables.

http://catalog.timken.com/WebProject.asp?CodeId=7.5.9.17&bookcode=trb12#

Kt = relative thrust load factor - ball bearings

Nc - number of rotations of the ball and cage assembly

No Fg.

 

[chris8189]

Thanks for the link. I've managed to find the definition of every variable, other than 'Fg'. This excel calculator task is proving to be quite a job. I'm struggling to say the least.

 

[Tmoose]

Can you see what the spreadsheet is doing with Fg?

 

[chris8189]

Yes - Fg = (mean diameter of inner ring x mean diameter of outer ring)/(mean diameter of inner ring + mean diameter of outer ring)

I still don't know what that is actually calculating though??