Bearings: Types, What it is & How they Work

Bearings are used to enable rotational or linear movement, reduce friction between two objects. They are easier to move (both in a rotary or linear fashion) and when friction is reduced, speed and efficiency of an object will be enhanced.

Bearings are split into two basic categories:

Radical Bearings - Support turning shafts

Thrust Bearings - Support axial loads

These types of bearings are intended to work with different thrust loads and radial loads. The major difference lies in accepting different weight with certain bearings a lot more resilient than others.

Different types of bearings

There are various types of bearings, which are specified based on their purposes, design to carry specific types of loads, thrust or radial.

The most popular types of bearings are ball bearings, Tapered Roller Bearings, Ball Thrust Bearings, and Roller Thrust Bearings etc.

1) Ball Bearings

Ball bearings have a niche area in the field of bearings as they can handle both radial and thrust loads. Every bearing is given a naming based on its rolling element and the same applies to the ball bearings also.

These bearings can handle less weights. In addition, ball bearings have special capacity to carry loads and they contain unique construction. They can be used in various applications such as roller blades, hard drives etc.

Other Names: “Deep grove ball bearing” (because of their constructional aspects)

The basic parts of a ball bearing include:

Inner Race - Inner race is mounted on the rotating shaft and tends to rotate the shaft.

Outer Race: Outer race is stationary and is mounted to the housing. It also helps to transfer the loads from the bearing to the housing.

Rolling Element “Balls”: The rolling element 'balls' will carry the load distributing it throughout the shafts.

Cage: Cage plays an important role in the bearing. It acts as a barrier between the balls preventing them from bumping into each other.

Applications:

Ball bearings can be used in various applications, such as:

a) Automotive Industry: Ball bearings are used in all motor vehicles. These are primarily used in parts such as steering, engine, driveline, and driveshaft.
b) Home Appliances: Ball bearings can be found everywhere in home appliances such as hair drier, washing machines, electric drill, and DVD players.
c) Paper-making Industry: These bearings are widely used in the paper-making machines. The bearings used for paper making machines operate under high-temperature.
d) Toy Industries: Toys will be designed to move through compressing springs or electric motors. Hence, ball bearings are included within the toys to move smoothly.
e) Aerospace: Ball bearings are extensively used in space shuttles, and rockets as they assist in easy and free movement.

Notations for Ball bearings:

The ball bearings are indicated with '6' as the starting series.

For example: 6006, 6204, etc

2) Tapered Roller Bearings

Tapered roller bearings can handle large radial and thrust loads. These type of bearings can be found in car hubs due to their load versatility.

The tapered roller bearings are designed to provide huge load versatility and equally effective at handling the large thrust and radial loads. This bearing is extensively used in automotive industry as it can lift the load, the wheels are expected to tolerate.

The basic parts of Tapered Roller Bearings:

Inner & Outer Rings: Tapered Roller bearings have inner and outer rings between which the tapered rollers are arranged.

The Inner ring with the rolling elements forms a unit, which in turn can be separately mounted on the Outer ring.

If the tapered surfaces are extended they will tend to unite towards a single point on the bearing axis. This proves that the rolling conditions for the rolling element are optimized.

The axial load carrying capacity of the bearing can be determined by the contact angle which corresponds to the angle of the outer raceway.

Notations for Tapered Roller Bearings:

The Tapered Roller bearings normally start with the series number of ‘3’.

For example: 30206

Applications of Tapered roller bearings:

Tapered roller bearings are majorly used in car hubs as they are capable to handle thrust in opposite directions.

They are also used in back-to-back pairs so that axial forces can be supported equally in either direction.

Tapered roller bearings are used in car and vehicle wheel bearings where they will manage simultaneously with large vertical (radial) and horizontal (axial) forces.

Tapered roller bearings are used in heavy duty applications, agriculture, construction and mining equipment, sports robot combat, axle systems, gear box, engine motors and reducers, propeller shaft, railroad axle-box, differential, and wind turbines, etc.

3) Ball Thrust Bearings

Ball Thrust Bearings can handle thrust loads in low-speed, low-weight applications. For example, bar stools use ball thrust bearings to support the seat.

As the name suggests, ball thrust bearings contain balls as the rolling elements in them. 'Thrust' suggests that the bearings are basically designed for carrying thrust loads or axial loads.

The bearings are basically available in two configurations as follows:

•    Single row thrust ball bearings
•    Double row thrust ball bearings

Notations for Ball Thrust Bearings:
The thrust ball bearings normally start with the series 5.
For example: 51105

4) Roller Thrust Bearing

Roller thrust bearings can handle larger amounts of thrust load. They can be found in car transmissions, where they are used to support helical gears. Gear support is a common application for roller thrust bearings.

As the name suggests, the cylindrical roller bearings are also specifically meant and constructed for the carrying of axial or thrust loads in the shafts.

The roller thrust bearings provide the below advantages. They are:

•    They have very low axial section height making space requirements much less for mounting and assembly.
•    They have a high load carrying capacity due to the presence of rollers, which bring about a line contact enabling the bearing to carry more load.
•    They posses high rigidity due to the constructional aspects of the bearing.

Constructional Aspects:
•    The roller thrust bearings consist of two outer races, called as 'washers'. One of the washers can be used for mounting as face located as well as shaft located. This bearing is made to check the direction of the axial load that enables the load to be transferred to the housing via the bearing.
•    The second washer or the race has a bore slightly larger than the first one and is normally a supporter of the rolling element at the other end.
•    The third is the rolling element which is held together by means of the cage.

There are two variants in the thrust roller bearings. They are

Thrust Cylindrical Roller Bearing – Single Row
Thrust Cylindrical Roller Bearing – Double Row.

Notations for Roller thrust bearings

The single row thrust roller bearings start with the series numbers 811 and 822.
For example: 81105.

The double row thrust roller bearings start with the series of 893 and 894.
For example: 89305

How do bearings work?

Bearings are made up of a ball and an inside, outside smooth surface for rolling. The ball will carry the load weight, and the force  of the load's weight assists in rotation of the bearing.

There are two different kinds of loading: radial and thrust.

o    A radial load, simply puts weight on the bearing, that causes the bearing to roll or rotate as a result of tension.
o    A thrust load puts stress on the bearing in an entirely different manner.

For example: Consider a bearing, if it is flipped on its side and subject to complete force at that angle, this is called thrust load.