Minibearings Speed - Bearings - Technical Information

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Minibearings Speed - Bearings - Technical Information

Bearing Speed / Limiting Speed

Limiting speed is the speed at which a bearing can operate at light loads and normal operating conditions without failing prematurely. It is a guide only. Application speeds can vary greatly.

Bearings in dental handpieces often run at speeds of up to 3 times their limiting speed, however they are not expected to last as long as bearings in less demanding applications.

Published limiting speeds apply to applications involving a rotating shaft. Speeds for applications involving a rotating housing can be up 30% lower.

Many factors combine to affect the attainable speed and expected life of a bearing. Factors affecting speed and life include ...

load
vibration
lubrication
cage type
operating temperature and internal clearance
moisture / contaminants
mounting
precision
closures

Limiting speeds can be found on our Minifind CD which can be ordered by our resellers.

Load

The limiting speed of a bearing is based on lightly loaded running conditions. Increasing the load will adversely affect the attainable speed and/or bearing life. An increase in either load or speed may sometimes be compensated by a decrease in the other resulting in a similar life expectancy.

It is important to note that a deep groove radial ball bearing should not be subjected to undue axial loads, and axial type bearings (such as angular contact or thrust bearings) should not be subjected to undue radial loads.

Vibration

Vibration is a major cause of bearing failure by causing brinelling or flaking of the races. If your bearings are operating under vibratory conditions you will not be able to achieve the same speeds that you could under perfectly smooth conditions. Attempting to increase speeds under vibratory conditions will quickly lead to bearing failure.

Lubrication

Lubrication is a major consideration with regards to bearing speed. We list a limiting speed for both standard oil and standard grease lubrication in the datasheets on our Minifind CD

Oil lubrication generally achieves higher speeds than grease lubrication. Increasing lubricant viscosity will reduce the permissible speed, whilst decreasing the viscosity will increase the permissible speed. Oil mists are used for very high speed applications. Use of silicone based oils and greases requires lower speed.

Cage Type

Often, the first part of a bearing to fail under high speed is the cage. The use of a synthetic cage designed for high speed helps to correct this. Synthetic cages are made from a variety of material including nylon, polyamide and phenolic. The datasheets on our Minifind CD show the limiting speed allowing for each bearings cage type.

Temperature and Clearance

Low or high temperatures can adversely affect bearing life. Low temperatures can cause components to become brittle and lubricants to harden. High temperatures can cause parts to bind due to expansion and lubricants to melt and evacuate the bearing. These effects can be somewhat controlled by use of an adequate high or low temperature lubricant and purchasing bearings with increased internal clearance to allow for expansion.

Moisture and Contaminants

Strict cleanliness is essential to the correct functioning of bearings. Bearings requiring contact with excessive moisture or even lubrication by water should be made from 316 stainless steel, acetal or even full ceramic. These materials are only suitable for low speeds and loads.

Mounting

Correct mounting is essential to the correct running of the bearing. A poorly aligned assembly, or incorrect housing/shaft tolerances will result in slower attainable speeds and premature failure. Incorrect housing/shaft tolerances can result in a lessening of the bearing internal clearance

Precision

The use of higher precision may be suggested if the bearing is to run at speeds above the standard limiting speed. MBA limiting speeds are already adjusted to take consideration of this effect.

Closures

Contact seals reduce the speed capabilities of a bearing. MBA limiting speeds are already adjusted to take consideration of this effect.

You can purchase MBA product from any of our Distributors or online from Small Parts and Bearings.

Resellers can log into their accounts on the MBA web site.

Miniature Bearings Main Pages

Technical Index

Product Technical Information

Balls	Bearings	Couplings
Pins	Shafting	Timing Belts and Pulleys

Other Technical Information

Basic Information Sheets	Catalogues	Glossary of Technical Terms
Links to Further Information	Materials Information	Measurement Conversions
Skate Bearing FAQ	Technical Information Sheets

Tables and information on this web site should be read as a general guide only. The relevant standards should be consulted to ensure accuracy

There are no further parts to this document.

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Site Summary:

Miniature Bearings Australia offers over 100,000 products including small bearings, timing pulleys, timing belts, seals, o-rings, gears etc - see the full listing in the Online Catalogue. Our main business is through resellers including the online only distributor Small Parts and Bearings and the counter sales distributor H.E. Supplies (Hobby Engineering Supplies). Small Parts and Bearings online sales are located within our building in Dividend Street Mansfield. H.E. Supplies are located just around the corner at 186 Wecker Road Mansfield. There are many other distributors located throughout Australia and Worldwide so there are hundreds of places to buy our product. Using the links at the top of this page you will find extensive information including catalogues (Products and Store link), technical data, and other product specific information.

We sell our product worldwide through distributors. If you are a distributor of mechanical parts such as bearings and power transmission products, and you have an interest in becoming a distributor for Miniature Bearings Australia in your area/country please contact sales@minibearings.com.au with information about your company. Miniature Bearings Australia are a wholesale and OEM supply company only. There are some foreign language introductory pages in French, German, Italian, Chinese, Japanese, Spanish and Portuguese available on our site.

If you wish to purchase product online, the Small Parts and Bearings online store is linked directly to the Miniature Bearings Australia online catalogue, so all new MBA products are added automatically to their store. Recent additions include full ceramic bearings in Silicon Nitride and Zirconia, and ceramic hybrid bearings for pushbikes and other applications. New products are being added every week. We also suggest that you may want to take a look at the technical information sites - Shafting Information, Couplings Information, Gearboxes Information and General Engineering Parts Information.

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