Bearings
Lubrication
Lubrication is a crucial "part" of any bearing application. Without proper lubrication, bearings can wear out faster, lose efficiency and fail prematurely. There are two main methods of lubrication: grease lubrication and oil lubrication.
Importance of lubrication
A lubricant performs several functions in a bearing, including:
- Preventing or reducing wear and tear
- Limiting friction to optimize performance
- Protect against penetration of dirt and contaminants
- Prevention of corrosion
- Dissipation of heat and wear particles
- Sealing support
Grease lubrication: the most commonly used method
In most applications, grease is used as a lubricant. Grease has the advantage over oil that it stays in the bearing better and is less likely to leak out. Standard sealed bearings are pre-filled with grease, usually around 30% of the free space in the bearing. Adding more grease than necessary can lead to overheating and increased operating temperature.
Lubricating greases: Which ones are there?
Lubricating greases consist of mineral or synthetic oils and are combined with a thickener. The most commonly used type is lithium soap grease, with an operating temperature range of -30 °C to +110 °C. However, depending on the working conditions, other greases may be required:
- For extremely low or high temperatures: Special greases with adapted chemical compositions.
- For high speeds or heavy loads: Synthetic or reinforced lubricating greases with additional additives.
Oil lubrication: when is it needed?
Although grease lubrication is often preferred, oil lubrication is used in certain applications, such as:
- Industrial machinery with a centralized lubrication system
- Applications where oil also acts as a coolant
- High speeds and high operating temperatures, where grease is no longer enough.
Oil lubrication can be applied via a drip system, oil bath, oil mist or circulation system, depending on the application and load requirements.
Which lubrication method should you choose?
The choice between grease and oil depends on several factors:
| Factor | Grease lubrication | Oil lubrication |
|---|---|---|
| Maintainability in bearing | Stays on better | Can leak away |
| Applications | General purpose, standard bearings | High-speed, heat-resistant applications |
| Maintenance | Minimum | Regular replenishment needed |
| Cooling capacity | Limited | Effective |