your global specialist Special knowledge The element that rolls the bearing. Tips and advice for the lubrication of rolling bearings

Speciality lubricants from Klüber Lubrication – always a good choice Lubricants for rolling bearings from Klüber Lubrication Selecting the right lubricating grease Grease application in rolling bearings Special lubricating greases Cleaning of rolling bearings Corrosion protection of rolling bearings Changeover of lubricating greases Bearing assembly using suitable pastes

Speciality lubricants from Klüber Lubrication – always a good choice Quality put to the test Humans and the environment – what really counts –– Klüber Lubrication has more than 110 test rigs, which include standardised equipment as well as tools Klüber Lubrication has developed to regularly test the quality of its products. –– Products that last a lifetime and enable minimum-quantity lubrication to be used help to save resources and reduce disposal quantities. –– Test results prove the high quality level and provide you with a solid basis for selecting the right lubricant. –– Speciality lubricants...

Lubricants for rolling bearings from Klüber Lubrication Rolling bearings are among the most important machine elements They may be designed as ball or roller bearings, radial or thrust bearings; what they all have in common is the transmission of load and power via rolling elements located between bearing rings. This is a simple and successful principle, at least as long as the contact surfaces remain separated. However, if the surfaces contact one another, there can be trouble ahead: the resulting damage caused may be anything from light, hardly perceptible surface roughening, pronounced sliding...

Selecting the right lubricating grease There was a time when a conventional lithium/mineral simple soap grease was deemed adequate for most rolling bearing applications. In the future, however, lubricants that are tailored precisely to a specific application will become more and more important. Even today the variety of lubricating greases available is immense, making correct selection increasingly difficult. In the following, the most important application selection criteria are provided to assist you in selecting the correct grease via a few simple steps. If you have any further questions,...

Determination of minimum base oil viscosity For determination of minimum base oil viscosity, the mean bearing diameter dm in [mm], the bearing speed and the bearing temperature under standard operating conditions are used. The required minimum base oil viscosity for the example shown at 40 °C (104 °F) = 38 mm2/s: To calculate the correct viscosity ratio for oil and grease, you should use the published base oil viscosities at 40 and 100 °C and apply them to the v-T diagram. Now figure out the viscosity v of the base oil at the operating temperature. (T) —(4) Steps 1-4 explain the order in which...

The actual base oil viscosity v should be v1 • 1.. .4. The Lubrication condition k following is generally used as a parameter indicating _ the expected lubrication condition: 4 Full fluid-film lubrication - k* = v / v1 = viscosity ratio - v = viscosity under standard operating conditions - v1 = required minimum viscosity, depending on mean bearing diameter and speed The following table provides an overview of the anticipated lubricating conditions indicating whether antiwear additives, EP additives or solid lubricants are required. > 4 In the regime of full fluid-film lubrication...

Speed factor The speed factor n ∙ dm for rolling bearings Bearing n ∙ dm value is determined by the speed of the bearing at standard operating conditions n in [min−1] multiplied by the mean bearing diameter dm in [mm]. The speed factor n ∙ dm for lubricating greases The attainable speed factor of a lubricating grease depends largely on its base oil type, viscosity, thickener type, and of course the bearing type used. Under high-speed bearing operating conditions it is important to achieve a constant oil supply at a defined rate within the bearing combined with optimum lubricant adhesion to the...

Load ratio C/P The ratio between the bearing’s basic dynamic load rating C in [N] and its actual equivalent dynamic load P in [N] under standard operating conditions allows conclusions regarding the requirements to be met by the grease. The values in the following table should be observed for the selection of a suitable grease. C/P Load Criteria for grease selection > 30 Very low loads Max. permissible load for silicone greases 20-30 Low loads Dynamically light greases 8-20 Medium loads Greases containing antiwear additives 4-8 High loads A grease with EP and antiwear...

Grease application in rolling bearings Around 90 % of all rolling bearings are lubricated with grease. Grease lubrication poses far less sealing problems than oil lubrication and allows much simpler machine designs. A further benefit of today’s highspeed grease formulations are operational speed factors up to 2 million n ∙ dm – more than twice of what used to be possible! It is not surprising therefore that grease lubrication of rolling element bearings is on the increase compared to the former use of oil lubrication methods. With grease-lubricated rolling bearings we differentiate between lifetime...

How much grease does the bearing need? For determination of grease quantities, once again the differentiation between lifetime lubrication and loss lubrication is of importance. The following diagram can be used to determine the free space in different types of bearings for initial lubrication purposes. Bearing series Curve Deep groove ball bearing 618 T-cage 8-9 Angular contact ball bearing 70 6 Cylindrical roller bearing NU1O 7 Spherical roller bearing Reference values for filling quantities (density approx. 0.95 g/cm3) Bearing free space according to Schaeffler: The bearing free...