Bearings are important mechanical components responsible for the smooth movement of machine parts. In order to maintain their optimal performance for as long as possible and to avoid bearing failure, proper periodic maintenance and inspection should be performed. Here are some of the most important checkpoints of proper bearing maintenance.
Careful and correct mounting
Good bearing maintenance starts with the careful and correct mounting of the bearings. Proper assembly requires professionalism and care, cleanliness and precision as well as the correct tools like bearing pullers, hook spanners, induction heaters, etc. that will reduce the risk of damage.
Bearings require high accuracy to do their job properly so it is very important that assembly is performed by qualified and well-equipped workers. Different methods should be used for different types of bearings. For example, bearings with cylindrical bores are usually mounted by pressing them on the shafts (press fit) or heating them to expand their diameter (shrink fit) while bearings with tapered bores, on the other hand, can be mounted directly on to tapered shafts or cylindrical shafts using tapered sleeves and an axial locking device (shaft nut, end cover).
There is one rule that must apply: mounting and dismounting forces should not be transferred over roller units and raceway. Bearings will only function properly if mounted correctly
Lubrication
Proper bearing lubrication is one of the most important factors that determine bearing performance and bearing life. The lubricant reduces friction and wear, prevents contamination and corrosion, and they serve as a cooling element that carries away the heat generated inside the bearing.
Bearings can be lubricated with either grease or oil. Roughly 9/10 of all bearings are lubricated with grease. The main advantage of grease over oil is that it is more easily retained in the bearing. However, lower speeds are possible with greased bearings than with oil lubrication. Where bearings are used at very low speeds and must be well protected against corrosion, it is recommended to fill the bearing housing completely with grease.
Different operating conditions require different lubricants, relubrication intervals, and lubricant change intervals. Regarding lubrication and relubrication, we recommend that you follow the instruction of the manufacturer.
Inspection and cleaning of bearing arrangement
Bearing arrangements should be inspected and cleaned regularly. Between detailed inspections of the entire machinery, noisiness and lubricants are controlled and temperature is measured. Frequency depends on the application type. After an arrangement is cleaned and washed (by using the correct cleaner), it should be well dried and oiled or greased in order to prevent corrosion.
Bearing storage
If bearings are stored in their original packaging, they are protected against corrosion for several years. Storage room humidity should not exceed 60%. Lubricant deteriorates over time as a result of aging, condensation, and separation of the oil and thickener. If sealed bearings are kept in the storeroom for a longer time, grease can solidify. After mounting, such bearings will have a higher moment of friction. This should be taken into consideration. Read more about bearing storage here.
Bearing failure
Despite careful design and manufacturing processes, it sometimes happens that bearings do not reach their required service life. Each type of failure leaves its own special imprint on the bearing. By examining failed bearings, it is possible to determine the root cause and define corrective actions to prevent a reoccurrence. Here you can find out more about bearing failures in electric motors.
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