Countless assemblies require bearings or bushings of some kind to ensure that certain components maintain smooth rotation or resist vibration and shock imposed by outside stressors. In this blog, we will be providing a brief overview of each, allowing you to better understand their respective roles, varying types, and common materials. First, it is important to distinguish bearings and bushings from one another, as they are often conflated.
A bearing is a mechanical element that helps maintain motion and reduce friction between two surfaces or components. A bushing works very similarly, providing an interface between two surfaces sliding against each other while also reducing friction. Due to their related roles, they are often used interchangeably. In fact, a bushing is a type of bearing that is used for specific applications. However, it is important to note that a bearing is not always a bushing.
A majority of bearings have similar structures and purposes, each designed with two surfaces that move over one another, allowing mating components to move with ease and without friction. The biggest differentiator among the following bearing types is whether they are moving with rotational or linear motion.
A ball bearing, or radial bearing, is one such type that is equipped with ceramic or steel balls that are located between the inner and outer rings of the bearing. They are designed to support rotating shafts while simultaneously reducing friction between the static and moving components. Additionally, a ball bearing assembly can have a single row or multiple rows, depending on the application at hand. Ball bearings are available as either deep groove ball bearings which have a high radial capacity, or as angular contact ball bearings, which manage both high radial and axial loads.
Roller bearings distinguish themselves in their ability to handle high loads. Cylindrical or tapered in shape, these bearings are tasked with minimizing friction between moving shafts and static components. Cylindrical roller bearings are typically made from stainless steel and are often implemented to handle heavy radial loads. You can find these bearings in high-speed applications, as their low-friction design does not produce heat or noise.
For low-speed applications, spherical roller bearings are a better option. Their self-aligning qualities are ideal for applications that experience vibrations or sudden shocks. Similarly, roller thrust bearings are also a feasible option that can handle misalignment. Lastly, when spherical roller bearings are installed on a double row, they can handle heavy radial and axial loads.
Often called bushings, journal bearings, or plain bearings, sleeve bearings are found in applications that use rotating or sliding parts. They are available in a variety of materials, but the most commonly used for its low-cost is plastic.
Metal sleeve bearings, nonetheless, are a good option, providing a low coefficient of friction. They are often overlooked due to the fact that they may rattle at high speeds. Steel can be lubricated to achieve a quieter assembly while still maintaining reduced friction.
A bushing’s performance and function is dependent on its material. Bronze bushings are often used for their durability and extended service life, making them ideal for a variety of applications. Moreover, they do not corrode easily. Despite this, they require lubrication during operation.
Plastic bushings, on the other hand, do not require maintenance or additional lubrication. Beyond their low cost, low friction, and self-lubricating qualities, there is no risk of corrosion, making them the optimal choice for wet or humid environments.
It is important to understand that plastic bushings have certain limitations. Firstly, plastic’s malleable characteristics make it unfavorable for heavy loads. Beyond cracking and damaging the bearing itself, the cracking of plastic may harm mating parts and increase friction. Additionally, they have a tendency to misalign if the plastic bushing is not manufactured precisely. While the rattling of metal dissuades operators from using metal bushings, plastic bushings can also generate audible noise if they are not properly fitted. More than that, they cannot be used in environments with excessive heat, making the material soften and thin.
If you find yourself in need of bearings or bushings, or other related components, rely on Purchasing Management 360. Purchasing Management 360 is a leading supplier with an inventory of over 2 billion new, used, obsolete, and hard-to-find items sourced from thousands of trusted global manufacturers. Kickoff the procurement process today, and a dedicated representative will reach out to you with a competitive quote for your comparisons in just 15 minutes or less.
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