Good lubrication plays a crucial part for many bearings. The right lubricant creates a protective film that provides a layer of protection. Without that protection, unwanted friction can create wear and tear that impacts the overall effectiveness of your parts – or worse, doom your bearings to an early demise. However, there isn’t one universal lubrication solution for every application. In general, there are three different types lubricants used for bearings.
- Dry lubricants
Oil lubricants come in both petroleum and synthetic forms and can be applied in several ways, including oil baths, jets, and circulation. Of the lubrication options, oils generally have the highest speed capacities and can cool the bearings during use, whereas too much grease can increase operating temperatures. However, evaporation can impact oil, which will lead to lubrication losses over time. This means that bearings using oil lubricants may require regular reapplication whether a recirculation system is part of the application design or not.
A grease is a base oil with some form of thickener that can create various consistencies ranging from a semi-fluid substance to a hard solid. These additives can also add additional protective capabilities, such as anti-corrosive, antioxidant, and other helpful characteristics to shield the parts from potential damage. The more solid nature of grease can make it a more attractive option for operations planning for little to no maintenance. However, greases won’t be able to handle the same high operational speeds as certain oils, which can limit your options depending on your application.
If grease or oil isn’t a viable solution, a dry lubricant like a solid film can help reduce friction. Substances like graphite or boron nitride provide a form of protection in harsh conditions where grease and oil won’t work, such as radioactive or vacuum environments, although these lubricants are typically a last resort and aren’t commonly needed.