The quality of a ball bearing is dependent on that of its weakest component: the lubricant. All too often, lubrication is the determining factor for the product’s longevity. The choice of lubricant is often a matter of compromise since it is dependent upon different operating temperatures and speeds.
In the case of grease lubrication, a judicious choice of viscosity and additives makes it possible in most cases to ensure the presence of an oil film preventing direct contact between metal components. However, the quantity of oil present in the grease is limited and the longevity of the bearing corresponds to the lifetime of the grease.
An oil lubrication increases lifetime provided the oil is regularly filtered and replaced. For certain applications, finding the perfect lubrication is impossible and metallic contact may still occur. In this case a "mixed lubrication" approach is used. In cases such as this, surface treatments can help increase lifetime.
In which cases could we use dry lubrication?
- Low temperature -200 to -50°C : low starting and working torque
- High temperature >200°C : a conventional lubricant will have a shorter lifetime and high gas losses. Some lubricants can produce toxic fumes.
- Low friction : Up to 50% less friction than conventional grease.
- Constant friction in an extended temperature range : no viscosity change as with grease
- High vacuum : no degassing, even in the UHV < 10-13 mbar
- Optical system : no contamination due to the lubricant
- Radiation environments
Dry lubricant solutions used instead of classic lubricant:
- Low load applications
Use in combination a classic lubricant:
- Friction and working temperature reduction
- Wear reduction and lifetime increase
- Maximum working speed increased
- Optical systems
- Cryogenic technologies
- Machine tools