Mastering Bearing Lubrication Technology to Extend Bearing Service Life
How to Extend Bearing Service LifeThree critical aspects of bearing lubrication are as follows:
• Cleaning
• Grease Filling
• Running-inNote: These procedures cannot be implemented in all working scenarios. Nevertheless, proper bearing cleaning, lubricant filling and running-in exert a decisive influence on extending bearing service life.High-speed precision machine tool spindle bearings adopting grease lubrication (initial grease filling) must be lubricated in accordance with specified lubrication procedures to guarantee normal operation. For applications under harsh operating conditions (e.g., bearings and lubricants operating near the rated speed factor, or bearings with lifetime lubrication), mastering relevant knowledge also facilitates stable operation.Core AdvantagesEnabling lubricants to operate at optimum efficiency requires correct and appropriate dosage of lubricant inside bearings, as well as maintaining the lowest possible and stable operating temperature of bearings. These are essential prerequisites for long service life and prevent excessive heat generation during high-speed bearing operation.
It should be noted that excessive bearing temperature will not only shorten the service life of lubricants but also reduce the operational precision of bearings.The bearing running-in direction shall be consistent with normal operating direction as far as possible. Furthermore, it is recommended to perform running-in at the actual application site (after transportation, handling and assembly) to achieve ideal running-in results.CleaningAs service life and reliability become increasingly critical for bearing applications, removing residual lubricating oil, grease and anti-rust oil before re-greasing grows more important. Clean contact surfaces can improve the adhesion of lubricating oil films. Removing such residual oils and greases effectively avoids potential incompatibility with newly filled lubricants. Complete cleaning of residues is strongly recommended before applying silicone-based or fluorine-based lubricants.Residual lubricant films on working surfaces of used bearings act as separators and hinder proper lubrication of rolling elements and raceways by new grease.
For high-speed applications (\(nDm>800{,}000\) or \(n/n_g>0.8\)), clean and dry contact surfaces are essential for re-lubrication to ensure adhesion between grease thickeners and bearing surfaces.Many bearing manufacturers pre-coat bearings with anti-rust oil before delivery. If the coating is extremely thin and compatible with the selected lubricant, pre-cleaning of bearings may not be required. Under such circumstances, communication with bearing and lubricant suppliers prior to grease filling is vital.Optimum lubrication conditions can be achieved by cleaning bearing surfaces with residue-free solvents. Before selecting suitable industrial solvents, local or factory regulations on solvent usage restrictions must be reviewed.CFC-113 (Freon) and methyl chloroform were highly effective residue-free solvents. However, regulations restricting ozone-depleting chemicals have banned the use of these solvents. Therefore, the best available residue-free solvents permitted by relevant regulations must be adopted.The cleaning standard for bearings, as well as the requirement for multiple cleaning cycles or ultrasonic cleaning, depends on operating conditions and contamination level.
Cleaned components are susceptible to atmospheric corrosion as they dry out. If lubricant filling cannot be carried out promptly, anti-rust agents shall be applied for preservation before storage.
Even if bearings are lubricated immediately after cleaning, unlubricated surfaces still tend to corrode. Therefore, it is advised to apply a small amount of anti-rust agent on other areas after filling lubricant.
• Cleaning
• Grease Filling
• Running-inNote: These procedures cannot be implemented in all working scenarios. Nevertheless, proper bearing cleaning, lubricant filling and running-in exert a decisive influence on extending bearing service life.High-speed precision machine tool spindle bearings adopting grease lubrication (initial grease filling) must be lubricated in accordance with specified lubrication procedures to guarantee normal operation. For applications under harsh operating conditions (e.g., bearings and lubricants operating near the rated speed factor, or bearings with lifetime lubrication), mastering relevant knowledge also facilitates stable operation.Core AdvantagesEnabling lubricants to operate at optimum efficiency requires correct and appropriate dosage of lubricant inside bearings, as well as maintaining the lowest possible and stable operating temperature of bearings. These are essential prerequisites for long service life and prevent excessive heat generation during high-speed bearing operation.
It should be noted that excessive bearing temperature will not only shorten the service life of lubricants but also reduce the operational precision of bearings.The bearing running-in direction shall be consistent with normal operating direction as far as possible. Furthermore, it is recommended to perform running-in at the actual application site (after transportation, handling and assembly) to achieve ideal running-in results.CleaningAs service life and reliability become increasingly critical for bearing applications, removing residual lubricating oil, grease and anti-rust oil before re-greasing grows more important. Clean contact surfaces can improve the adhesion of lubricating oil films. Removing such residual oils and greases effectively avoids potential incompatibility with newly filled lubricants. Complete cleaning of residues is strongly recommended before applying silicone-based or fluorine-based lubricants.Residual lubricant films on working surfaces of used bearings act as separators and hinder proper lubrication of rolling elements and raceways by new grease.
For high-speed applications (\(nDm>800{,}000\) or \(n/n_g>0.8\)), clean and dry contact surfaces are essential for re-lubrication to ensure adhesion between grease thickeners and bearing surfaces.Many bearing manufacturers pre-coat bearings with anti-rust oil before delivery. If the coating is extremely thin and compatible with the selected lubricant, pre-cleaning of bearings may not be required. Under such circumstances, communication with bearing and lubricant suppliers prior to grease filling is vital.Optimum lubrication conditions can be achieved by cleaning bearing surfaces with residue-free solvents. Before selecting suitable industrial solvents, local or factory regulations on solvent usage restrictions must be reviewed.CFC-113 (Freon) and methyl chloroform were highly effective residue-free solvents. However, regulations restricting ozone-depleting chemicals have banned the use of these solvents. Therefore, the best available residue-free solvents permitted by relevant regulations must be adopted.The cleaning standard for bearings, as well as the requirement for multiple cleaning cycles or ultrasonic cleaning, depends on operating conditions and contamination level.
Cleaned components are susceptible to atmospheric corrosion as they dry out. If lubricant filling cannot be carried out promptly, anti-rust agents shall be applied for preservation before storage.
Even if bearings are lubricated immediately after cleaning, unlubricated surfaces still tend to corrode. Therefore, it is advised to apply a small amount of anti-rust agent on other areas after filling lubricant.
