RADIAL BEARINGS CYLINDRICAL ROLLERS
Four-row cylindrical rollers radial bearings are used almost exclusively in the rolling stands. They have a lower friction than the other rollers bearings and they are suitable for applications where high speeds are required.
The reduced radial encumbrance of these bearings lets the adoption of big diameter necks compared to lamination roll.
In the four-row cylindrical rollers bearings, rollers are driven on the outer ring between integrals edges or not integrals. The inner ring is devoid of edges. The bearing can cope, within certain limits, to axial displacement of the tree compared to the lodging. Depending on the application, bearings like this can be provided with cylindrical bore or conic. The rings, inner and outer, can be just in one piece or into several pieces. Bearings with more than four rows cylindrical rollers and equipped cages are mostly used for big cold rolling mills for plane products, where lamination efforts are considerable and the speed very high. Bearings with more than four rows are produced for necks of the cylinders with diameters over about 220 mm.
The outer ring is equipped with two not integral edges, while the rullers are self-guided. The inner ring is devoid of edges, so bearings can face an axial displacement of the tree compared to the casing.
The encumbrance sizes of radial cylindrical rollers bearings with several rows listed in the tables comply with the norm ISO- 15-1981.
Excluding specific customer requests, four row radial cylindrical rollers bearings are normally manufactured with dimensional precision class P6 and form precision class P5, and those with six rows according to the normal precision. To consult the tolerances values please consult the tables on page 24-25-26.
Four row cylindrical rollers radial bearings are manufactured with a radial inner clearance C3 or C4, while those with six rows have variable clearances according to the use. On customer request, however, we can provide bearings with different clearances to these one. All bearings of this type, that have an helical groove in the hole of the inner ring, are manufactured with radial inner clearance C2. To consult radial clearance values please consult the tables on page 27.
For this kind of bearings it is not expected any kind of misalignment.