On the specifics of the use of lubricants in the bearing

We decided to create a new column called BBC-R Persons. It is created to introduce you to the people who work in our Company. They will talk about the most important and interesting in their work and a little about themselves.

We decided to start with a specialist, without whom the production of bearings cannot function at all. Please meet Technical Director Vitalii Micherevskii.

Vitalii, could you please say a few words about your job as Technical Director of a bearing manufacturer? What are your responsibilities?

– The main responsibilities include as follows: production process monitoring, control over the quality level of products, implementation of new engineering solutions, improvement of production processes and much more.

One of the most important aspects of the operation of such a technical unit as a bearing is lubrication. It is known that there are many lubricants for a wide variety of conditions. So, what are the reasons, except for friction reduction, of lubrication used in bearings?

– Yes, you are absolutely right. Lubricants used in bearings are the most important component of the correct and trouble-free operation of the bearing assembly throughout its entire service life.

In addition to friction reduction, the main functions of lubrication in a bearing include as follows:

·  Formation of a strong oil film on the contacting surfaces, protecting them from wear and early fatigue breakdown
·  Reduction of noise and unwanted vibrations
·  Corrosion protection

It is also worth distinguishing between greases and oils (liquid). In the case of greases, they serve as additional protection against the ingress of solid and liquid contaminants from the outside. In turn, oils serve as excellent heat dissipation.

Which bearings need to be lubricated?

– This is a rather broad question, but to put it simply, all bearings must work lubricated. It is not recommended to use bearing without lubrication, as friction occurs between metals, without separating the surfaces with an oil film, which leads to rapid wear, temperature rise, fatigue failure and, as a result, to early bearing breakdown.
Closed versions of bearings are usually supplied with an embedded lubricant, and under normal conditions of transportation, storage and operation, they imply reliability throughout the entire service life. Exceptions are modifications that operate with constant lubrication circulation, oil fog, oil bath or with lubrication systems, whether automated or manual.

When should the grease be changed? Is it true that if the grease is used for 5 in a bearing, it must be replaced?

– If we are talking about a closed version of a deep groove ball bearing, which is protected by sealing elements (for example, design 2RS, ZZ) and the use of grease, then in the case of correct use of the bearing (which means a clean environment, absence of vapours, dirt, fine dust, etc., permissible loads and rotation speed), as I said above, grease replacement is not required throughout the entire service life.

There are bearings, with special holes or nozzles to add grease, which are used in particularly dirty environments. For example, it includes agriculture, heavy metallurgy, and mineral extraction. Often, we do not have complete information on the operating conditions of bearings in detail and for such products we cannot provide reliable information on the frequency of replacing or adding lubricants in each case, since the conditions are quite severe, contaminated and difficult to predict. But we will definitely provide you with advisory information.

Of course, replacement of lubricants after 5 years of operation is a myth widely discussed on thematic forums on the Internet.

Which bearings should we use high-temperature grease only?

– The main area of ​​application of high-temperature grease is bearing assemblies, which imply operation in an environment with constant or variable temperature increases up to values ​​higher than standard, as well as in conditions where, due to high loads on bearings, friction increases, and as a result, the temperature inside the bearing rises. This type of grease is characterized by a specially selected composition of base oil and thickening agent, with a package of additives that prevent the grease from degrading when operating at high temperatures. Typically, this type of lubricants is used in bearings with increased radial clearance.

How does BBC-R indicate a lubricant fill rate and type on bearing packages? Are common designations or in-house codes used?

– The fill rate is not indicated on the package in any way. We can provide this information at the customer’s request.
In practice, it is customary to use the term – the percentage of filling from the free volume in a bearing. Simply put, free volume is a free space inside the bearing, bounded by the plane of end surfaces, raceways, rolling bodies and a retainer ring, if any.
In world practice, the standard fill rate is considered to be 25-35%, but this figure differs within this range, depending on the manufacturer.

The fill rate, depending on the lubricant used, its characteristics, future operating conditions and many more factors, is calculated for each type of product separately. Naturally, this is a standardized value regulated in our Company by approved calculation methods.

Could you tell us which lubricants are used by BBC-R and why do you use the best brands?

– We use lubricants produced by such companies as Fuchs, Bechem, Koyodo Yushi, Mobil, Gazpromneft in the production of bearings. The quality of products and customer satisfaction are priorities for our Company, therefore we do not cut corners on the materials used, which, moreover, can affect the quality of the final product.
Our lubricant suppliers are large and well-known manufacturers that guarantee and ensure a consistently high quality supply, conduct research and testing of their products, have extensive expertise in applied disciplines and provide excellent advice in the selection of lubricants.

What innovations is the Company preparing in your area for the near future?

– Speaking on the topic of lubricants, currently, we are developing, with our team of specialists and engineers, a new product for the market – lubricants used in bearings. In short, it will be several types of grease, with different characteristics, used in different operating conditions of a bearing, such as different operating temperatures, grease with improved performance under standard operating conditions, grease for heavy-duty conditions and several more types, but unfortunately, I cannot tell about everything right now.

– Thank you for the interesting and highly professional story, Vitalii, we hope to get acquainted with the new developments of the Company in the field of lubricants soon.