Rolling bearings are one of the essential components of machines and equipment and are used for relative motion between machine elements. This makes them one of the most important components in the engineering field. In recent decades, rolling bearings have been developed from the single row to the multi-row, from the radial to the double direction and from the conical to the convex. As technology advances, the types of rolling bearings have become more and more diverse. This article will discuss the types and codes of rolling bearings.
The rolling bearing is divided into two main types — radial and non-radial. Radial bearings are bearings that support radial loads, while non-radial bearings support axial, radial, and angular loads. Non-radial bearings are referred to as angular contact or axial thrust bearings.
The radial bearings are further subdivided into single-row (or plain bearings), double-row and multiple-row bearings. Single-row bearings form an axis with the bearings rolling elements and its outer ring, while double-row and multiple-row bearings form two or more axes. Single-row bearings are limited in their ability to withstand axial loads, whereas double-row and multiple-row bearings can accommodate both radial and axial loads.
The various types of radial bearings are designated according to their row configuration and their internal components. Deep groove ball bearings are either single-row or multiple-row, and are composed of an outer ring, inner race, one or more rows of balls, and cage. Cylindrical roller bearings are composed of an outer ring with two rings, one or more rows of rollers, and a cage that guides the rollers. These are designated by the type of internal construction, size and material of the bearing, and the types of cages that hold the rollers.
There are several types of thrust bearings. Thrust ball bearings support thrust loads and size adjustable axial loads only. In tapered roller bearings, one conical roller is placed between two flat raceways, and they can accommodate both radial and axial loads.
Non-radial bearings include angular contact bearings, axial thrust bearings, and crossed roller bearings. Angular contact bearings are a type of radial bearing with the inner and outer raceways on different planes. They can accommodate a combination of radial and axial loads. Axial thrust bearings are cylindrical or conical bearings that only support axial load. Crossed roller bearings are also a type of radial bearing with two circles of cylindrical rollers running in perpendicular directions. They can accept both radial and axial loads.
Each type of bearing has a code that is used to identify it. For radial bearings, the code consists of three parts: the bearing type, size, and material. For example, a deep groove ball bearing with a 50 mm bore size, made of stainless steel, is identified as a 6200XRS. In angular contact bearings, the code usually consists of four parts: the bearing type, size, preload class, and contact angle. For example, a light preload angular contact ball bearing with a 50mm bore size and 25 degree contact angle is identified as 7310AACM. While the code for thrust bearings is similar to the radial bearings, double-direction thrust bearing codes also include the number of rows and columns. For example, a double-row double-direction thrust bearing with two rows and five columns is identified as 7920ALBNC.
In summary, rolling bearings are essential components of machines, suitable for transferring forces and motion between two or more parts. There are various types and categories of rolling bearings, and each type has its own unique code that can be used to identify it. Therefore, it is important to understand the different types and codes of rolling bearings in order to correctly select the best one for the given application.
