Why Should Only One Bearing Support Axial Loads?

[YongzZ]

Hello,

does anyone know why for a shaft with 2 bearings A and B, why is it not good engineering practice for both bearings to support axial and radial loads? while it is better if one supports axial and radial loads while the other bearing only support radial loads.

 

[FredGarvin]

If you have two bearings that are taking up axial loads, they will have a tendency to fight each other when it comes to sharing the loading. A common set up is to have one bearing take both axial and radial loads and the other to control the concentricity of the shaft by just taking radial loads. This way one bearing has to worry about endplay, etc...while the other bearing allows for things like length adjustment or expansion due to heating by not constraining the shaft in two directions.

The other reason is economics. It is usually cheaper to find a roller bearing for the job than an angular contact bearing.

Here's a nice introductory article that talks a bit about this issue:
http://www.engineeringtalk.com/news/skf/skf137.html

 

[YongzZ]

Thank You!