To minimise friction in transmission, precision is paramount. As a result, bearing lubrication is required to make sure rolling components remain functioning effectively.
There are several reasons why bearing failure may occur, including improper mounting and overloading. However, lubrication itself can be a contributing factor if an incorrect product is selected, applied improperly or the correct level of preventative maintenance is not adhered to. Read on to explore what makes lubrication in components and bearings so crucial.
Why is lubrication vital for bearings?
One of the key roles of a lubricant is to help ensure smooth and continuous power transmission during mechanical operation. However, lubrication also creates a barrier in-between components inside the bearing. For example, it lubricates the rolling element, the inner ring, the outer ring and the shield, when required. This effective barrier offers multiple benefits that can help improve the longevity of a bearing, as well as the other components in a system and the full production line.
What tasks does lubrication perform in bearings?
Lubricants provide a wide range of services on bearings, which allow them to function at optimum performance while protecting them from harm and extending their active service life.
Lubricants are designed to prevent the process of oxidisation and minimise the impact of corrosive forces which can cause lasting damage to bearings and their components. Lubrication also creates a protective film that seals working parts against unwanted debris, effectively forming a contaminant barrier.
Lubricants stabilise the bearing structure, but also allow bearing components to move freely by reducing friction. In turn, this decreases wear, which occurs over time during extended use.
What are the different types of bearing lubricants?
Lubricants must always be selected for bearings while considering multiple factors. These include material, the load type and any adjoining components. The reason for this is because some lubrication solutions suffer heavy affection from onsite environmental factors, while others cannot remain effective at the speeds necessary for specific operations. As a result, it is critical to be aware of the lubrication types available based on their base material and viscosity index.
Grease lubricants
A grease lubricant typically consists of an oil base with a thickening agent added, which allows the consistency of the grease to range from a semi-solid to a fluid state. Due to this range, grease lubricants offer varied applications for bearings and do not require an intensive maintenance schedule.
It is worth noting that grease is a partial-solid lubricant, which means that it cannot cope with off-kilter mounting and high-load speeds. However, the extra properties of a grease lubricant can help in other areas. High-quality greases can provide outstanding protection against issues like oxidisation and corrosion.
Oil lubricants
In contrast to grease lubricants, petroleum-based and synthetic oils can take much higher load capacities and load speeds. Consequently, they are highly suitable options for use in high-volume mechanical operations and can help prevent expensive downtime.
However, oil is highly fluid in composition, which makes it prone to the issue of evaporation in applications where the bearing is not encased with a dedicated shield. Under such circumstances, operators must follow a consistent maintenance schedule that features a series of application measures like the use of oil baths and jets.
Dry lubricants
Sometimes referred to as solid film lubricants, dry lubricants are the third and final category of bearing lubricant. Popular products choices include tungsten disulphide, boron nitride, graphite and molybdenum disulphide. These dry lubricants are applied by burnishing or sputtering them onto the bearing to form a solid film within the balls and raceways.
It’s worth mentioning that these lubricants are typically seen as a last resort choice which is mainly used for extremely harsh environments which are radioactive or vacuum sealed.
Points to consider when picking a lubricant
Finally, when choosing one of the three bearing lubricants listed above for power transmissions components and mechanical operations, there are some aspects to consider.
Operating temperature of a mechanical application is a key concern. High speeds and high mean high heat and the lubricant selected must have the capacity to tolerate this temperature. Oil lubricants are prone to evaporation, so grease can be a better option if contaminants present and external conditions permit its use.
Speed of the bearing is also a concern, along with the friction maintenance required to prescribe under such operating conditions. Grease lubricants cannot tolerate high speeds, but both synthetic and petroleum-based oils can offer the protection required for bearings.
The condition of the mechanical operation is also key. When harsh conditions like high contamination, a vacuum environment or radioactivity are present, it’s vital to mitigate downtime by choosing a solution that can withstand such extreme conditions, like a solid film lubricant.
To provide ultimate protection and maintain optimum performance levels for your bearing application, ensure you always select the best lubricants for the job.
