Types Of Bearings And How They Work

Posted by Bradley Irwin on February 2, 2018

Bearings enable metal machinery parts to move smoothly and quietly, without the friction that can lead to the wearing out of these parts.

Without the use of bearings, we would be required to regularly replace parts when they get worn out. That would increase downtime, costs for parts, and efficiency.

In a nutshell, bearings make for less effort, easier movement, and reduced friction.

How Do Bearings Work?

When you move a large wooden block or stone on any surface it is difficult to move. Put it on some pipes and you will find the same weight very easy to move.

Bearings work on this same relatively simple concept. Anything that rolls will move more smoothly than anything that slides. A car on wheels will move more easily than a sled, which will require greater efforts to both push and maneuver.

Friction between things that slide is greater and will slow down its movement, whereas when surfaces roll over each other the reduced friction will allow for ease of movement. Bearings have smooth metal balls or rollers and smooth inner and outer surfaces against which these devices rotate. These rollers or balls also bear the load of the device and allow it to spin smoothly.

What Types of Bearings Are There?

There are many types of Bearings, and each of them will have a specific purpose. The most common type is the ball bearing. These are by far the most common. For example, they are found in roller skates and hard drives.

They can handle both thrust and radial loads and are common in applications where the loads imposed on the bearing are small. The load gets transmitted from the outer race to the ball and from there to the inner race. The ball being a sphere makes contact at a very small point and this helps smooth movement. This also restricts the amount of load the bearing can take, and an overloaded bearing will have balls that get deformed or crushed.

Roller bearings, on the other hand, have rollers that are cylindrical. This helps to greatly increase the contact area and hence the ability to bear greater loads. The contact is a line and not just a point, which allows the load to be transferred to a larger area.

However, roller bearings are not as effective when there is also a thrust load. For this case, a variation of a roller bearing, called a needle bearing is much more effective. The cylinders used in a needle bearing are of a very small diameter.

You will also find bearings that use balls that can take thrust. These are used for low speed applications. Similarly, roller thrust bearings can take on large thrust loads and are commonly used in gears and rotating shafts.

A further variation is tapered roller bearings that can take large radial and thrust loads. These bearings are mounted in pairs, with rollers tapered in opposite directions, so that thrust from either direction can be easily faced.

The quantities of balls, rollers, or pins in bearings help to reduce the force that is required to move that object.The increase in the number reduces the friction, as each of them helps to distribute the weight.

Last modified on February 2, 2018

Categories: Bearings, Needle Roller bearings, Tapered Roller Bearings, Thrust bearings

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