preload on a bearing

[Buhsman]

Are there any simple calculations to use to figure out what the preload should be an a bearing?

Thanks in advance.
Kyle

 

[brengine]

Not the answer you're looking for, but maybe helpful. We use Duplex bearings and are able avoid this calculation and possible pitfal of incorrectly assembled/preloaded bearings. Just match the rated Duplex pair to your application and place to spacers (one on inside race and one on outside race) that were ground together between the bearings. The bearings are made with the 2 races slightly offset, therefore when you squeeze them together against the same size spacers, an exact/repeatable preload is induced and they cannot be "over" preloaded...unless you can apply enough torqure to crush the race, but then you've got another problem on your hands

Ken

 

[EdDanzer]

Preload on a bearing depends on the type of bearing, the size of bearing, rotational speed, lubrication, load and operating temperature. Other parameters such as materials used in the shaft and housing, housing size, and more can have an effect.
If you are doing repair, check with the manufacture, or find a similar product with a defined preload. If it is a new product, contact some of the bearing manufactures for help, or post more information here.

 

[EnglishMuffin]

I would suggest that this question belongs in the "Bearing design, manufacture and maintenance forum".
EdDanzer's comments are all valid.
However, KenBolen's claim that using spacers gives an exact/repeatable preload is not really true in my experience. In practice, it is very easy to compress the spacers, especially if they are long. It is very important to control the force applied to the spacers, whether this is done with a locknut or some other means. The preload can also be heavily influenced by the fit of the bearing races, which varies from bearing to bearing. The majority of the preload often comes from this rather than any axial offset applied, and can often vary by a factor of two or more even if the spacers are all identical. Often, the most challenging thing about rolling element bearing preload is checking what it actually is, rather than deciding how much it should be. However, in many applications it is not super critical.