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Rolling Bearings Rolling bearings are mechanical components which allow relative motion between two surfaces with minimum friction. They have been in use for hundreds of years and are fundamental in almost every type of machinery. This article will provide an overview of rolling bearings, their types, components and applications.
Rolling bearings normally comprise of two hardened metal rings that are separated by a layer of lubricated steel balls, rollers or cylindrical bars. These components are referred to as races, washers and rollers respectively. The rollers, rolling in the races under the action of applied forces, cause a rolling action to take place between the two surfaces and allow them to move in relation to one another.
Rolling bearings are commonly classified into radial, axial and tapered types, depending upon the type of motion they enable. Radial bearings are the most popular form and are suitable for both rotational and convertible motion. Axial bearings are used to reduce axial thrust, i.e. to control thrust in one direction only. Tapered rolling bearings are designed to accommodate rotational, translational and tipping motions.
Rolling bearing components can be further distinguished by their load carrying capacity and the type of lubrication employed. Depending upon the bearing application, typically either grease or oil lubricants are employed. Grease lubrication, usually consisting of a petroleum base oil plus a thickener and additives, is used for slow speed applications that require extended lubrication intervals. Oil lubrication, consisting of a variety of synthetic oils, is most suitable for higher speed operation and also offers better cooling and wear protection.
The components of rolling bearings must be carefully designed and manufactured with high precision in order to obtain the best performance. Factors such as load, speed and environment conditions (temperature, humidity, contamination, lubricant, etc.) must be taken into consideration when selecting the bearing type and components.
Rolling bearings are widely used in diverse applications ranging from automotive, aerospace, agricultural and industrial machinery to medical practices and home appliances. Automotive applications make use of a variety of rolling bearings including ball bearings, deep groove ball bearings, tapered roller bearings, needal roller bearings, thrust bearings, rolling element bearings and bearing nuts. Bearing design is of particular importance in aerospace applications; as the environment can be particularly harsh (high temperatures, contamination, vibrations, etc.). Railcars and agricultural equipment also depend heavily upon their bearings for smooth operation. Many home appliances, medical practices and industrial machines employ rolling bearings for the same purpose.
The use of rolling bearings in the construction of machinery is still essential today; however, due to their continuous innovations, today’s rolling bearings are vastly superior to their predecessors. The advent of computers, together with advances in material science and machining precision, has allowed rolling bearings manufacturers to develop faster, more robust, higher capacity, smaller and more efficient bearings. In a nutshell, rolling bearings are mechanical components which are essential for almost all machines, from simple to complex.
Rolling bearings remain one of the most vital components in manufacturing with applications extending beyond machines. Whether it is for automotive, industrial, aerospace, agricultural or medical purposes, rolling bearings play a crucial role in permitting relative motion between parts with minimum friction. Furthermore, developments in their design, manufacturing, materials and lubrication, allow for superior performance today compared to earlier models. The importance of rolling bearings cannot be emphasised enough and the continued advancements in their technology ensure that they will remain a fundamental part of our engineering processes for years to come.
