Understanding Different Types of Thrust Bearing and How to Avoid Their Failure
Bearings are useful devices for “bearing” the force of a load while facilitating rotation between two or more components. One common type of bearing is the thrust bearing which can support a force exerted in the same direction as the shaft(s) it is connected to. As with any other piece of equipment, certain measures can be taken to prevent damage or failure from wear. In this blog, we will discuss several different types of thrust bearings as well as ways to prevent common types of bearing failure.
What Are Thrust Bearings?
Thrust bearings are essentially axial bearings which means that they are meant to bear force exerted directly on their center or axis. Axial force, as opposed to radial force, permits the rotation of attached rotables, serving to assist axial thrust of both horizontal and vertical shafts. To visualize this, you might imagine sitting on a small stump. If you were to sit on the top of the stump, you are exerting axial force but if that stump fell over and you sat on it as it lay on its side, you would be exerting radial force. Thrust bearings are specially built to bear axial force while still being able to rotate with and between moving parts.
Types of Thrust Bearings
There are several types of thrust bearings available to fit each application. Here are some of the general types:
Thrust Ball Bearing: These bearings have several balls inside of a band around their perimeter. Even when a force is applied to one side of the bearing, the balls can easily roll and support rotation of the bearing and the parts it connects. Thrust ball bearings are used in low thrust applications where there is little axial load. In addition, they are available in two designs: single direction and double direction.
Cylindrical Thrust Roller Bearing: In place of free-moving balls, these bearings use cylindrical rollers embedded in their band which rotate along with the two sides of their casing. They offer good carrying capacity and can support more weight in general than ball bearings.
Tapered Thrust Roller Bearing: This type of bearing uses embedded cylinders, but is tapered on one side of the disc. As a result, the cylinders are set at an angle pointing to a place above the center of the disc, rather than directly inward. Due to this shape, tapered thrust roller bearings can support greater loads and are designed to accommodate combined loads which may act simultaneously as axial and radial loads.
Spherical Thrust Roller Bearing: These bearings offer the highest load rating density of all thrust bearings. They have a similar design to tapered roller bearings, but have rollers which are slightly off center, creating a more spherical shape rather than a simple cone or circle.
Structures of Thrust Bearings
When choosing the right bearing, it is important to consider the direction of load it will need to support. Some bearing types are more suited for a radial load, others for an axial load, etc. If the bearing will be subjected to an axial load (exerting in the same direction as the shaft), then thrust bearings should be used, but if the bearing will be subjected to force which is perpendicular to the shaft, a radial bearing should be used.
3 Major Causes of Thrust Bearing Failure and How to Avoid Them
When a bearing does fail, it is important to determine the cause so that adjustments can be made. The three most common causes are as follows:
Contaminants: Airborne dust, dirt, sand, water, chemicals, and corrosives are all common forms of contaminants which can affect thrust bearings. To identify this kind of damage, look out for denting of rolling elements and raceways that could cause added vibration. One way to avoid this kind of damage is to filter lubricant and clean work areas, tools, fixtures, and hands to reduce the risk of contamination.
Misalignment: Misaligned equipment can lead to excessive vibration and inability to handle the load. Some signs of this kind of damage are visibly bent or off-placement components. To prevent this, be sure to inspect shafts and housing regularly, use precision-grade locknuts, and shim the housing as needed.
Overloading: Putting too much load on a bearing is another common cause of failure. In such cases, you will want to look for heavy rolling-element wear paths, evidence of overheating, and widespread fatigue areas to identify this type of failure. One way to fix it is to reduce the load or consider a redesign using a bearing with greater capacity.
Conclusion
Thrust bearings are an effective way of managing the axial force of a load while facilitating rotation between multiple parts in a machine. There are several common causes of thrust bearing failure to keep track of and measures you can take to prevent failure from happening. If you are on the search for high quality thrust bearings or other cabin crew safety parts, the Internet of NSN is here to help! With an inventory of over 2 billion new, obsolete, and hard-to-find components, we are ready to support all your parts needs. To begin the procurement process, simply fill out an Instant RFQ form as provided on our website to receive a response tailored to your situation in 15 minutes or less!
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