Bearings are reliable even under tough conditions and they last long if used and maintained properly.
The life of a bearing can be determined based on a time period or a number of rotations. After a certain time or rotation, the rolling elements or inner and outer rings fail. According to studies, less than 1 percent of bearings do not reach their expected life. Having accurate data and diagnosis can save a bearing from repetitive failure and expenses.
How to Lengthen the Life of Your Bearing
Lubricating a bearing covers the rolling and sliding contact surfaces. The thin lubricant film helps avoid direct metal-metal contact. This reduces friction, abrasion, and heat transfer because of friction. Benefits of proper lubrication include:
- Longer Service Life
- Rust and Corrosion prevention
- Prevention against Contamination
In lubricating bearing, grease is used because of its manageability and effectiveness in the sealing systems. Oil lubrication is more suitable for high-speed and high-temperature operations.
Causes of Lubrication Failures
- Using the wrong type of lubricant
- Wrong amount of grease
- Wrong amount of oil
- A mixture of grease or oil
- Grease or Oil contamination
Addressing Lubrication Related Issues
Lubrication grease or oil needs to be applied in the exact amount and schedule. To address lubrication issues such as bearing location, oil or grease amount, and lubrication schedule, you may install an Automatic Lubrication System. An Automatic Lubrication System supplies lube points with metered amounts of grease or oil from a central location. This ensures that the right amount of lube is supplied to your machine at the right time. This saves you and your maintenance team from dangerous bearing locations, manual oil amount measurement, and application schedule. A precise application of lubricant reduces the overall required amount. The pump station, complete with the controller. The risk of an accident is minimized and maintenance downtime drastically reduced.
- Centralized Grease Lubrication System- centralization of a lubrication system makes operation and maintenance efficient and safer by making lubrication points accessible and ensuring that critical components are lubricated with the right amount of grease and at the right time.
- Automatic Pressure Booster Lubricator - The are many automatic lubricators that are designed with pressure booster as high as 10 bar that allows delivery of a lubricant in a long lubrication line or high counter-pressures. Some are designed with additional features that allow for connectivity to smartphones which makes configuration and monitoring readily available on hand.
It is important to use the proper tools and ovens/induction heaters in mounting and installing bearings. Use a sleeve to affect the entire inner ring face in fitting the bearing. It is important to put into consideration the shaft and housing tolerances.
If the fit is too tight, you will create too much preload.
If the fit is too loose, you will have too little preload.
Check the installation and bearings for proper diameter, roundness, and chamfer radius. Always remember to avoid misalignment or shaft deflection. This is vital in mounting bearings that have separable components. Parts such as cylindrical roller bearings should be accurately aligned for optimal performance and a longer life span.
Always be wary of maintaining the proper radial internal clearance (RIC) that was set up for the original design. The standard scale in ascending order of clearance is C2, C0, C3, C4, and C5. Following the proper clearance in installing the bearings is important. The proper clearance allows accuracy in lubrication, shaft fit, and heat.
The film of lubricant must be able to cover the rolling elements to reduce and avoid direct metal-to-metal contact. Reducing clearance and lubricant flow will lead to premature failure, follow the proper guidelines in installing the bearings.
In shaft fitting, reduction in the radial internal clearance is inevitable when the bearing is press fit. It produced heat in the normal operation of bearings, this creates a thermal expansion of the inner and outer rings. This will reduce internal clearance that can reduce the optimal bearing life.
C. Addressing Causes of Premature Bearing Failure
Bearings fail prematurely because of factors that could have been avoided. Studying the appearance of the bearing is vital in reaching conclusions about the cause of a defect. Correcting the failure causes is critical in preventing future failures and the costs that follow.
These are the usual bearing failures:
- Unusual Wear Patterns
These factors are attributed to a group of causes that are often interrelated and correctable. These include lubrication, mounting, operational stress, bearing selection, and environmental influence.
D. Grease Service Life
Besides the normal bearing service life, always be wary of the normal grease service life. The time over which proper bearing function is sustained by a particular quantity and category of grease is called Grease Service Life. This is very important in the pump, compressor, motor, and super-precision applications. Grease undergoes oxidation when exposed to air and other elements of nature. Unless a bearing is completely sealed and comes with a lubricant, grease needs to be routinely replaced. Grease mainly consists of thickener and oil. When the level of oil content becomes too low, grease loses its serviceability and you need to purge it and replace it with a fresh one. Machinery Lubrication provides a calculator that computes the quantity and frequency of grease application that you need to use according to your application. You can also contact Le Price reliability engineers to help you determine the right kind, quantity, and frequency.
E. Operational Stress and Bearing Selection
There are typical abnormal bearing sounds that show certain issues in the bearing application. Know that a tick or screech usually shows discrepancies in internal clearances or poor lubrication on a cylindrical roller bearing. A crunching sound when the shaft is rotated by hand suggests that the raceways have been contaminated. Operational stress can affect bearing life as well. It is important to isolate vibrations in the associated equipment, this ensures smooth running and optimal bearing life.
F. Environmental Influence
The best design, proper lubrication, and installation will not guarantee that failures will not occur unless the operating environment is always monitored. These are the primary issues you should look out for:
- Contamination - Dust and dirt can contaminate a bearing. Always remember to use proper sealing techniques to prevent contamination.
Microbial Contamination - Water will cause microbial contamination which will decrease the life of your bearings. Specialty-type seals are recommended to prevent Microbial Contamination
Heat - The recommended operating temperature dictates many choices in radial internal clearance.