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Preloading Ball Bearings Part IV: Frequently Asked Questions

Over the last three installments of the Bearings Blog, we’ve been examining preloading; follow the links below to catch up:

Part I: What is preloading and why it’s important

Part II: Spring and fixed constraint

Part III: Axial adjustment and duplex bearings

In today’s post, we continue our preload tutorial and look at a few frequently asked questions. Have a question we didn’t address? Toss it to us here and we’ll be happy to answer!

How much preload should be applied?

In general, provided the design requirements are met, the least amount of preload is desired

What are the benefits of preload?

Rotational accuracy and precise shaft positioning, elimination or reduction of ball skidding, control and reduction of axial and radial deflection under applied load, noise reduction, load sharing between bearings

Does preload have any effect on a bearings operational life?

Bearing life decreases as preload is increased

What other side-effects of preload should I know about?

With increased or excessive preload, stresses are higher and excess heat is generated

Which preload method should be used?

Preload selection varies based on bearing type. For example, Miniature and thin section ball bearings have different internal geometry compared to larger radial and angular contact ball bearings. Be sure to follow the manufacturer’s guidelines, or consult with a bearing engineer.

What about preloading for machine tool spindles?

Machine tool spindles must be capable of resisting deflection from multiple directions while maintaining both rotational and positional accuracy. Duplex bearings with their high rigidity and accuracy are ideal for this application.

Remember, in addition to serving as your one-stop-shop for bearing products, AST also offers a variety of value-added services including engineering consulting and design. Our engineers and bearing experts can assist you in optimizing preload, or any bearing-related challenges: contact them here.

Our series on preload will be wrapping up with a final post on May 13, stay tuned!