Lubrication and maintenance are important for the reliable operation and long operating life of FAG and INA rolling bearings.

Functions of the lubricant

The lubricant should:

• form a lubricant film on the contact surfaces that is sufficiently capable of supporting loads and thus preventing wear and premature fatigue
• dissipate heat in the case of oil lubrication
• give additional sealing of the bearing, in the case of grease lubrication, against the entry of both solid and fluid contaminants
• dampen running noise
• give protection against corrosion.

Selection of the type of lubrication

It should be determined as early as possible in the design process whether FAG or INA bearings should be lubricated using grease or oil.

The following factors are decisive in determining the type of lubrication and quantity of lubricant:

• the operating conditions
• the type and size of the bearing
• the adjacent construction
• the lubricant feed.

Grease Lubrication

In the case of grease lubrication, the following criteria must be considered:

• very little design work required
• the sealing action
• the reservoir effect
• long operating life with little maintenance work (lifetime lubrication possible in certain circumstances)
• if relubrication is required, it may be necessary to provide collection areas for old grease and feed ducts
• no heat dissipation by the lubricant
• no rinsing out of wear debris and other particles.

Oil Lubrication

In the case of oil lubrication, the following criteria must be considered:

• good lubricant distribution and supply to contact areas
• dissipation of heat possible from the bearing (significant principally at high speeds and/or loads)
• rinsing out of wear debris
• very low friction losses with minimal quantity lubrication
• more work required on feed and sealing.

Design of lubricant feeds

The feed lines and lubrication holes in the housings and shafts.

• should lead directly to the lubrication hole in the FAG rolling bearing
• should be as short as possible.

A separate feed must be provided for each FAG or INA bearing.