ASHWANI KUMAR on 10/25/2022 8:29:10 AM


Bearings are a crucial component of many types of machinery and exist in a variety of forms and shapes. They can be defined as a component that permits only a specific type of motion in a system that may be under static or dynamic loading.

A bearing is a precision-made machine component that allows machinery to move at extremely high speeds, while reducing friction between moving parts and handling stress. Most bearings are used to support rotating shafts in machines


Bearing, in machine is, a connector (usually a support) that permits the connected members to rotate or to move in a straight line relative to one another. Often one of the members is fixed, and the bearing acts as a support for the moving member.

Main function of bearing:

-To reduce friction between moving rotatory parts.

-To support rotating parts of a machine.

-To bear radial and thrust load.

-Minimize maintenance expenses

Components of bearing:

Bearings usually consist of the following components:

-Two rings or discs with raceways

-Rolling elements in the form of rollers or balls

-A cage which keeps the rolling elements apart and guides them

Inner Ring / Outer Ring

The inner and outer ring are usually made from a special high-purity, chrome alloy steel. 

This material has the necessary hardness and purity – both important factors for a high load rating and a long service life.

The raceways are hardened, ground and honed.Special materials such as ceramic and plastics are also used. Although plastics cannot withstand extremely high temperatures, they are considerably lighter than steel. This makes them invaluable in sectors such as the automotive industry, where every gram matters.

Inner ring-      

Outer ring-  

Rolling elements-  

Rolling elements are either balls, rollers, cones, spheres or needles. They are usually made from a special high-purity, chrome alloy steel. Special materials such as ceramic and plastics are also used.

The rolling elements roll on the specially formed raceways of the rings or discs and are kept apart and guided by the cage


The cage is responsible for keeping the rolling elements apart and guiding them. The materials used include steel, brass and plastic. Solid metal cages can be produced using machining techniques, while pressed cages are made from sheet metal. Similarly, plastic cages can be machined from solid plastic or injection moulded.

Types of Bearing

Bearings can be classified based on different criteria, such as design and operating mode, allowed motion, or direction of load. From a design perspective, the classification of bearings is as follows.

Plain Bearings :

Plain bearings, also referred to as bushes, bushings or sleeve bearings, are usually cylindrical in shape and contain no moving parts.

Plain bearings are used for sliding, rotating, oscillating or reciprocating motion

Plain bearing construction may be solid or with a split joint (wrapped bearings) for easier installation.Plain bearings are manufactured with different constructions and product selection depends on the operating conditions of the application and performance requirements.

Ball Bearings :

Ball bearings are one of the most common types of bearing classes used. It consists of a row of balls as rolling elements. They are trapped between two annulus-shaped metal pieces. These metal pieces are known as races. The inner race is free to rotate while the outer race is stationary.

Ball bearings are used for controlling oscillatory and rotational motion.