Double Row Angular Contact Bearing Axial Load Capacity

[RoscoeCoach]

I often run into applications where the system was designed using double row angular contact bearings having very little axial load and mostly radial loads. But then sales finds a application where it is primarily an axial load condition, and they ask "how much axial load can this system handle". Normally when I dig into it further and discover what the customer actually wants I can lead them into a different product that it better suited for the application. However the question still remains, how much static and dynamic axial load can a double row angular contact bearing handle? It seems like a very simple question, even the major bearing suppliers state that a angular contact bearing can handle larger axial loads, but none of them actually list these values in their tables.

I understand the equations P = XFr + YFa or P = Fr + YFa, but can I simply reverse this to solve for Fa assuming that Fr is 0 or very very small?

For example, what is the static and dynamic axial load capacity of a INA 3201J2RS bearing assuming pure axial loading (25deg contact angle, 2100 lbs dynamic radial load, 1100 lbs static radial load).

Simple "rule of thumb" is great, but I would really like to see the "proof" behind it.

Thanks for the help.

p.s. I realize that I can change to thrust bearings and solve this issue very quickly, but that doesn't really help me. The manufactures state that it can handle larger axial loads, I simply want to place a value what that load actually is.

 

[caoimhin1]

As always, when someone asks "what load can I put on a bearing", the answer is "what lifetime do you want". If Fr is zero, then just use the equations you gave above to calculate the dynamic equivalent load. For a 25degree, it will be P = 1.41 x Fa

 

[Tmoose]

Was rpm mentioned yet?

Another thing to consider is "unloading" the opposing bearing, which invites skidding and its own type of damage. Preload springs can help if the load is uni-directional. For an increase in axial capacity it is possible to add bearings, like this. <<> .

 

[RoscoeCoach]

I did not specify the life or the RPM, because I want to values to be equivalent to what the bearings are rated for. So if the dynamic radial load rating is based on 1,000,000 revolutions then I would like to know what the axial load rating is for the same life and RPM. For Static loading life and rpm are not necessary.

Thanks for the help.