Lubrication and handling

âž” page 13 ).A single bearing package cannot be opened without breaking the industrial seal, this proves that the bearing is in “mint” con- dition and has not been exposed to undesirable environmental conditions.

Lubrication Bearing handling

SKF cylindrical roller bearings can belubricated with grease or oil. There is no strict boundary where one type of lubricant is more appropriate than the other. The upper temperature limit for greases based on mineral oils is about 120 °C for continuous operation. The limit is much higher for oil lubrication and even higher if synthetic oils are used, provided that the cage and other components of the bearing arrange- ment can withstand the higher tempera- tures.The advantage of grease over oil isthat grease is more easily retained in the bearing arrangement. This is par- ticularly important in applications where the bearing axes are vertical or at an angle.On the other hand, oil lubricationallows operation at higher speeds and temperatures and contributes to the removal of frictional or applied heat from the bearing position. SKF cylindrical roller bearings withan injection moulded cage of glass fibre reinforced polyamide 6,6 are particularly suited to grease lubrica- tion. The special cage bar design enables the build-up of a grease reser- voir by adhesion. This allows mainten- ance intervals to be extended, goodperformance under emergency condi- tions and help to prevent bearing seiz- ureunder lubrication starvation. The greases generally recommend-ed for cylindrical roller bearings have a consistency of 2 and may contain EP additives. Where the bearings are subjected to axial loads, the grease should have an oil bleed to DIN 51817:1998 (IP 121/75:1992) of ap- proximately 3 %. For this reason, high-temperature greases should only be used when the operating tempera- ture is always above Before packaging, SKF cylindrical roller bearings are treated with a rust in- hibiting medium and can be stored for several years in their original packages. The bearings should be stored lying down, preferably in rooms that are free from vibration, have a relative humidity that does not exceed 60 % and where the temperature is reasonably con- stant.When purchasing, make sure thatthe SKF cylindrical roller bearings are in their original packages ( = / +80 °C. Similarly,greases with a consistency of 3 should only be used if, for example, strong vibrations favour distribution of the grease. To enhance the operational reliabilityof axially loaded cylindrical roller bear- ings SKF recommends using a grease or oil with a viscosity that is at least 1,5 times the requisite viscosity for the operating temperature (viscosity ratio
1 1,5). If an axial load is appliedfor long periods (> 1 h),the relubrication intervals should be shortened. 22