How do you lubricate bearings

intact. Ludwig Meister's blog

 


 

Reduction of friction and wear in roller bearings and ball bearings through optimal lubrication

Even the best rolling bearings can only function reliably if they are properly lubricated.

Choosing the right lubricant, but also the right lubrication method, namely adding the right lubricant and the right amount of clean material to the rolling bearing at the right time, play a crucial role.

Around 36% of premature bearing failures are due to insufficient lubrication. Multi-purpose greases can e.g. B. be more harmful than useful for certain applications. Due to the large number of storage cases and operating conditions, particular attention must be paid to the selection of the suitable lubricant.

 

Functions of the lubricant

The functions of a lubricant can be varied and, depending on the application, required alone or in combination. In addition to the primary requirement for the lubricant - maximum power transmission with minimum friction and minimum wear - different secondary properties must often be met, such as: B.

  • Water resistance,
  • Chemical resistance,
  • Plastic compatibility or
  • Corrosion protection.

Correct lubrication is of great importance for a long service life of rolling bearings. Lubricants increase the efficiency and service life of rolling bearings by avoiding friction, corrosion and thus premature wear. They ensure good heat dissipation, dampen vibrations, prevent the penetration of solid and liquid substances at sealing points and thus reduce repair and maintenance costs.

 

Rolling bearing lubricants

Basically, the designer is faced with the question of whether the roller bearing should be lubricated with oil or grease.

When choosing a lubricant, environmental influences (dust, temperature or humidity) and design factors (material, surface or geometry of the friction bodies) play just as important a role as stress factors (speed, pressure load or vibrations).

You can find rolling bearing lubricants in our webshop

 

 

Below are some key considerations for lubricant selection.

 

Oils

The viscosity is a measure of the viscosity of a liquid substance. The higher the viscosity, the thicker (less flowable) the liquid is; the lower the viscosity, the more fluid (flowable) it is.

The viscosity of an oil changes depending on the temperature as well as the pressure and shear stress. The most important influencing factor is temperature. The viscosity decreases with increasing temperature and vice versa.

The selection of the viscosity of an oil depends on the area of ​​application of the lubricant. Basically

The rule is that low-viscosity oils are suitable for low pressure loads and high sliding speeds. A high viscosity is selected with a high pressure load, low sliding speeds and high temperatures.

At high speeds or temperatures at which grease lubrication is no longer possible, oil lubrication is recommended. This ensures that the heat generated by friction or the environment is sufficiently dissipated. Furthermore, due to their low viscosity, lubricating oils achieve a very good lubricant distribution and thus also ensure that the lubrication points are kept clean. Lubricating oils consist of mineral or synthetic oils, which are mixed with different additives depending on the purpose.

 

Fats

The vast majority of roller bearings are lubricated with grease. The advantage of grease lubrication is the high consistency of the grease. They enable lubrication in all installation positions, seal, for example, bearing points against the ingress of dirt and prevent corrosion due to their water-repellent effect.

As with lubricating oils, greases are differentiated according to the viscosity of the base oil, which is the decisive part in the selection of grease. In addition, the Consistency class plays a role in fats. The consistency is the resistance that a fat exerts against its deformation. DIN 51818 divides lubricating greases into NLGI classes according to their consistency:

000, 00, 0, 1, 2, 3, 4, 5, 6.

Rolling bearing greases generally have NLGI class 2 or 3

Lubricating greases consist of mineral or synthetic oils, additives and thickeners (mostly metal soaps, but there are also others such as the common polyurea), e.g. B. lithium, sodium or calcium soap. Base oil and additives are crucial for the properties of the lubricating grease. The thickener part is responsible for the desired consistency (NLGI class).


Product / service

We offer you professional initial greasing of your rolling bearings with special greases especially for your applications, even for small quantities.

You can find out more about this service here

 

 

 


 

Selection of the lubricant

The essential criteria for the selection of a suitable lubricating grease are not only the roller bearing size, the operating temperature, the operating speeds and the bearing load, but also soft environmental factors. These include B. Lowest temperatures during start-up or peak temperatures, entry of liquid or solid impurities into the bearing, frequent start-up processes or oscillating movements, strong shock loads.

Here you can download the lubricant selection tables from our suppliers for rolling bearing lubricants.

 

These contain suggestions based on the most commonly used greases in typical applications.

You can find rolling bearing lubricants in our webshop