Rolling Bearing Identification
Rolling bearings are key components of many industrial equipment and motorized products and serve to reduce friction and improve the efficiency of their operation. Bearing identification marking is one of the key steps for properly identifying and evaluating rolling bearings. The markings usually consist of alphanumerical characters which identify the bearing manufacturer, product type, production characteristics, and serve as an identification code for individual bearing components.
Most commonly, the OEM part number (by the original equipment maker) appears first. The last digits of this number could be the actual bearing identification number, which allows you to easily find the right bearing based on its dimensions.
The National Precision Bearing is the most common and useful way to identify rolling bearings. This Bearing Prefix Code, typically identified on the bearing ID markings, is used to specify the precise type of bearing being used. There are seven basic parts to the prefix code, each representing a specific characteristic of the bearing, such as the bearing type and size.
In cases of ball or roller bearings, normally it is possible to identify the bearing type of the product as well as its size (diameter, width, bore diameter and seal type) by closely examining the ID markings.
In addition to the prefix code, bearing numbers may have a suffix code, ranging from one to three letters. The suffix of the bearing number may consist of symbols providing specific information about the bearing such as manufacturing tolerances, seals, material, lubrication option and cage type.
Other letters used in the bearing ID numbers could denote seals and lubricating systems, thermal treatment and depth of grooves for conveying purposes. The numerical digits of the ID may indicate bearings type, bore diameter, ring and separator width, along with other dimensions.
In cases of bearing housings or identical products, the ID markings generally specify the dimensions and type of the product, including bore diameter, outside diameter and length. On mounted bearing units the marking will provide information such as shaft diameter, overall length and mounting hole distances.
It is important to take into account that there might exist some cases, where bearing identification is difficult, due to the very composition or size of the bearing. In such instances, special techniques or tools should be used to identify them.
Bearing identification is one of the most important steps in the selection of rolling bearings, and it requires a correct interpretation of the products ID markings and codes. Bearing identification is a necessary step to ensure the proper and safe installation and operation of rolling bearings. It is thus advisable to refer to the bearing manufacturers catalog and drawings for further information, in order to avoid costly mistakes and improper bearing installation.
