In this article we learn what is bearing and the types of bearings.
What is Bearing?
A bearing is a machine component that supports another running machine component known as a journal.
Allows relative movement between members’ contact surfaces when carrying loads.
Due to the relative motion between the contact surfaces, there is friction and wear. Therefore, to reduce friction and wear and to eliminate the heat generated, lubrication can be provided.
Commonly used lubricants are oils, silicone oils, lubricants, etc.
Functions of Bearing
The bearing provides support to the shaft or axle and keeps them in the correct position.
Facilitates free rotation of shafts or axles with minimal friction.
It also retains the power acting on the shaft or axle and transmits them to the frame of the machine.
Types of Bearings
Bearings can be classified in different ways. The most commonly used types of bearings are as follows :
- Sliding contact bearings
- Rolling contact bearings
1. Sliding Contact Bearings
These bearings are also called plain bearings, in these bearings, the sliding surface moves between the moving element and the fixed element.
2. Rolling Contact Bearings (Ball Bearings)
In rolling contact bearings, the contact between the bearing surfaces is rotated instead of sliding in the case of contact bearings.
The main advantage of a rolling contact bearing over a sliding contact bearing is that it has a low starting friction. Due to this property, these bearings are also called antifriction bearings.
Since the rolling elements and the races are subjected to high local stresses, the material of the rolling element is steel. The balls or rollers are generally made of high-carbon chromium steel.
These bearings are commonly used in gearboxes, motors, machine spindles, pumps, axles, etc.
These bearings consist of the following four major parts:
1. Outer race: It rests in a frame or casting and it is generally stationary.
2. Inner race: It is mounted on the shaft and rotates along the shaft.
3. Rolling elements (Balls, Rollers, etc.): While transmitting the motion rolling elements permit the relative motion between the inner and outer race.
4. Separator or retainer: The retainers are thin strips and made in two parts which are assembled after the balls have been properly spaced. Separators or retainers are used to keep away the balls or rollers so that they do not touch each other.
Types of ball bearings
The ball bearings are classified as follows
1. Single-row deep groove ball bearings
2. Double-row deep groove ball bearings
3. Angular contact bearings
4. Self-aligning bearings