Bearings - Why We Need Them and What They Are Used For
By Helen Cox

The concept behind bearings is a very simple one - things move better when they slide. Bearings are basically used to allow constrained relative motion between two parts. They are used to reduce friction between shafts and axles in a number of applications and are often used to absorb weight placed on a moving part. They are a very important piece of machinery that is present within a lot more applications and machinery than you may realise.

Bearings are generally found in applications that range from automobiles, airplanes, computers, construction equipment, machine tools and DVD players as well as refrigerators and ceiling fans. The list of things that bearings are present in really could go on but let's just put it simply; if an application/piece of machinery twists, turns or moves it probably has a bearing in it.

They are highly engineered and precision made components, which enable machinery to move at extremely high speeds and carry remarkable loads with ease and efficiency. They must be able to offer high precision, reliability and durability, as well as the ability to rotate at high speeds with minimal noise and vibration. It is thanks to these bearings that the use of machines everyday is possible. Without these bearings we would be constantly replacing parts that were worn out from friction.

When it comes to bearings there are many different kinds available; each of which are used for different purposes. These different types include ball, roller, thrust and tapered roller thrust bearings. Out of all the different types of bearings that are available to you however, ball bearing are the most common. It is these bearings that can handle both radial and thrust loads. Depending on what application or piece of machinery the bearing is being used in depends on whether there is all radial loading, all thrust loading or a combination of the two of these.

Going back to ball bearings, they are found in everything from in-line skates through to hard drives. In general however they are normally found in applications where the load is relatively small. The main purpose of it is to reduce friction and to support radial and axial loads. The way in which it achieves this is by using at least two races to contain the balls and transmit the loads through the balls. One of the races is usually held fixed and one of the bearing races rotates in order to cause the balls to rotate. As the balls are always rolling they have a much lower coefficient of friction than if two flat surfaces were rotating on each other.

Out of all the rolling element bearings that are available, ball bearings tend to have the lowest load capacity. The reason for this is they have a smaller contact area between the balls and the races. On the plus side however ball bearings are the least expensive rolling element bearing available this is thanks to the low cost of producing the balls that are used in the bearing.

Making sure the bearings in your applications and machinery are up to scratch is an important factor as they could prolong the life of your applications and machinery. So make sure you get either steel ball bearings or ceramic ball bearings as these are the main two materials used and will ensure the best productivity.