How Bearing Numbers and Codes Affect Bearing Life?

The search for a perfect bearing can often be a daunting task, bearing catalogs regularly featuring countless numbers, letters, and codes that many may be unfamiliar with. As the choice of bearings can easily make the difference between smooth operations and failing assemblies, it is crucial that one has a basic understanding of bearing systems, their numbers, and codes. In this blog, we will provide a brief overview of such practices, ensuring that you can find an optimal fit for your needs.

When researching rolling bearings, one may find that such components are listed alongside codes that convey their dimensions, construction, tolerances, and clearances. Tolerances are an important characteristic, that of which determines the amount of unintentional deviation that a bearing dimension may have from its nominal value. Allowance, meanwhile, is the intentional deviation that exists between mating surfaces, combining the tolerances of both.

Codes may come with various sections to determine such qualities, often being presented with prefixes and suffixes alongside the basic code. With such details, one can quickly find what type of bearing a particular component is, and the diameter of its inner ring. With the use of prefixes, the basic elements of the bearing may be discerned. Lastly, suffixes are used to indicate any special designs that the bearing exhibits.

The bearing code is useful for discerning what type of bearing a particular code represents, coming in the form of letter and number combinations. Typically, such values convey construction, diameter, and width series. As an example, tapered roller bearings often have codes such as 313xx, 320xx, and 329xx. Meanwhile, spherical roller bearings may feature codes such as 213xx, 222xx, and 230xx. Bore numbers, on the other hand, are useful for finding the bore diameter. In the instance that a bearing only consists of the basic bearing code, such components will have been built to common standards of precision, form, and clearance.

When a prefix is featured on a bearing code, such strings refer to basic elements found on the bearing. As an example, a prefix such as “S” would denote that the bearing is stainless steel, while an “HR” or “IR” prefix would denote that the bearing component is a needle roller bearing that is constructed in inch style. Suffixes are fairly similar, allowing for one to determine if there are any special characteristics of the bearing. Oftentimes, these suffixes will encompass special outer forms, precision tolerances, cages, clearances, heat treatment, and more. With suffixes such as “E”, “UA”, “UO”, and “UL,” one can discern the internal design of a bearing. With suffixes like “X”, “K”, “N”, “NR”, and “U”, on the other hand, the outer surface dimensions may be found. Beyond such examples, other common suffixes include those for sealing, cage materials, bearing clearances, and precision tolerances. As a final major suffix type, some may be used to denote dimensionally stabilized bearings, each conveying the maximum operating temperatures of various components.

If you are in need of top quality bearings for your various operational requirements, look no further than NSN Target. NSN Target is an online distributor of aircraft parts, and we are unmatched in our prices and lead-times. Explore over 2 billion currently available items at your leisure, and you may begin the purchasing process at any time. When you find particular items that you are interested in, we invite you to take advantage of our RFQ service in order to quickly request quotes for your comparisons with ease. As our team members are readily available for customers 24/7x365, responses will be given in as little as 15 minutes or less. Get started today and see why customers choose to steadily rely on NSN Target for all their operational requirements.


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