Why Relubrication Matters

Regreasing becomes highly essential for ensuring operational benefits. Knowing the right and reliable lubricants and the frequency with which they should be used can come in terrifically handy.

Rolling element bearings, often called as bearings, are one of the most common components found in modern day machines. They find their applications in a variety of equipment ranging from electric motors to gearboxes as well as conveyor systems, and can be broadly categorized into – Ball bearings, Cylindrical roller bearings, Spherical roller bearings, Needle roller bearings, and Tapered roller bearings.

These bearings undergo a regimented lubrication pro-gram which involves timely relubrication to replace grease that has deteriorated, leaked away, or become contaminated. It takes on the spot know-how backed by expertise to determine the relubrication intervals in rolling element bearings owing to the varying conditions these components operate under.

Determining relubrication frequency

The question that now arises is – how often should one relubricate rolling element bearings? There isn’t a specific answer to this question since there are numerous factors that influence relubrication frequency.

Generally, the smaller the bearing and faster the speed, the less frequent is the interval for relubrication. For instance, ball bearings have a base interval for relubrication, whereas for a cylindrical roller, the relubrication frequency is almost five times more, relatively.

Some of the factors that determine the regreasing interval of the bearings are as follows:

Operating Temperature:

Higher temperatures increase a grease’s oxidation rate, doubling it for every 18ºF (10ºC). For example, a bearing operating at 250ºF (120ºC) will require greasing 10 times as often as one operating below 150ºF (65ºC). Grease softens as temperatures increase and may become fluid enough to leak out of the housings.

Environmental Conditions:

Environmental conditions that subject bearings to contamination add on to the relubrication frequency. Bearings exhibit
unusual conditions such as excess heat emission, noise, leakage, vibration, etc. under such conditions.

Adding Grease between Flushing Intervals:

Many rolling element bearings require relubrication with small quantities of grease between grease flushing intervals. If the seals are in good condition, the quantity of the grease needed may be small and infrequent.

Having factored in the causes that determine relubrication intervals and accelerate the process, the immediate requirement to be addressed is the way in which relubrication challenges can be mitigated.

Greases for relubrication

ExxonMobil™ offers premium greases for rolling element bearings that promise effective relubrication. Some of them are:

Mobil Polyrex™ EM Series

The advanced thickener formulation and proprietary manufacturing techniques of Mobil Polyrex EM Series provide improved bearing performance and protection for long electric motor life. These greases are recommended for long-life lubrication of electric motor ball and roller bearings.

Key features:

Enhanced grease life ensures longevity, high-temperature lubrication of ball and roller bearings, particularly in sealed-for-life applications;
Advanced polyurea thickener increases durability versus conventional polyurea greases when subjected to mechanical shear forces;
Low-noise properties are beneficial for lubrication of ball bearings in many noise-sensitive applications.

Mobilith SHC™ Series

The Mobilith SHC Series greases are superior performance products designed for a wide variety of applications at extremes of temperature.

Key features:

High and low temperature performance enables protection at high temperatures and low torque;
Protection against wear, rust and corrosion reduces downtime and maintenance costs;
Structural stability in the presence of water retains excellent grease performance in hostile aqueous environments.

Mobilgrease XHP™ 220 Series

Mobilgrease XHP 220 greases are designed for a wide range of applications including the industrial, automotive, construction and marine sectors. Their performance features make them an ideal choice for operating conditions including high temperature, water contamination, shock loading and extended re-lubrication operations.

Key features:

Resistance to water washout and spray-off helps assure proper lubrication and protection even in the most severe water exposure conditions;
Rust and corrosion resistance offers protection of lubricated parts even in hostile aqueous environments;
Broad multi-purpose application provides potential for inventory rationalization and reduced inventory costs.

Relubrication is paramount for ensuring effective performance, protection and long life of rolling element bearings. When the process of relubrication is accomplished using the right lubricant, the benefits are in the interest of time, maintenance cost, productivity and profitability.

When the process of relubrication is accomplished using the right lubricant, the benefits are in the interest of time, maintenance cost, productivity and profitability.