Single row cylindrical roller bearings are able to carry large radial load on a relatively small space. Some applications are able to carry also axial load in one or both directions. Raceways of the outer and inner rings together with the sheet profile of the cylindrical rollers in the shape of ZB allow optimal distribution of the contact pressure in the rolling space. This arrangement also allows advantageous formation of lubrication film between the contact parts of the bearing, optimal rolling, decrease of friction, growth of temperature and therefore lower stress of the junction in the arrangement.
At the same time certain mutual misalignment of the rings is allowed and so the bearings cope better with the real operating conditions and contribute to a better reliability and durability during the operating life of the bearings. Cylindrical Roller Bearings are suitable for arrangements, with high requirements for load transfer in connection with high rotation speed, e. g. machine tools, rolling mills, vehicle axle, etc.
Main dimensions of cylindrical bearings are specified in the dimension tables and they are in accordance the international standards ISO 15.
Structure
Cylindrical roller bearings generally consist of two parts – outer or inner ring block on which with the help of cages and guiding ribs cylindrical rollers are fastened and second, separate ring. This arrangement allows separate mounting of rings and so the manipulation of indiviudal parts is made easier. Through the gradual development and introduction of new possibilities in the materials and processing technologies better utilization of the inner bearing space and introduction of application with higher load marked “E” was enabled. Bearings with steel cage are offered in the whole range with higher load. Higher load bearings with brass cage are dependent on technological possibilities and they are indicated in
the table section.
Separate group are bearings with brass cage where rib is joined to the cage body by unriveting of cross pieces. This arrangement allows more efficient utilization of inner bearing space and offers better working properties mainly in connection with durability. Designation of these bearings is done by additional letters „EDM“.
The Following Constructions are the Most Common
NU
The cylindrical rollers are guided by cage between two ribs of outer ring. The inner ring is ribless, which allows mutual bearing rings displacement.
NJ
Similar to NU, but inner ring contains a rib on one side. The bearing can accomodate axial force in one direction.
NUP
The outer ring is manufactured with two ribs, loose inner ring contains solid rib on one side, from the other side is flat angle ring attached. This type of bearings can be used to carry axial forces in both directions.
N
The cylindrical rollers are guided by cage in inner ring with two solid ribs. The outer ring is rib less, relative axial bearing rings displacement is possible.
NF
The inner ring with two solid ribs, outer ring with one guiding rib.
HJ
Angle rings, which use allows to accomodate axial load from needed direction.
Possible combinations of angle ring HJ with bearings:
NJ+HJ, NU+HJ
We do not recommend the combination of NU bearing with two angle rings, because of axial nipping of rollers can occur.
The illustration of the combinations is above the table chart.
Tolerance
The cylindrical bearings are commonly manufactured within the normal tolerance class P0. Production of bearings with higher tolerance classes is necessary to consult with manufacturer. Limiting values of dimension deviations and operation are stated in the standards ISO 492.
Radial Clearance
The commonly manufactured cylindrical bearings are with normal radial clearance or with radial clearance C3. For special applications cylindrical bearings can be supplied with radial clearance C2 (smaller than normal) or with clearance C4, C5 (greater than normal and C3). Radial clearance values are in accordance with the standard ISO 5753. These values are
valid for manufactured and unassembled bearing.
Stabilisation for Operation at Higher Temperature
For operating temperature higher than 120°C specially stabilized single row cylindrical roller bearings with stabilized dimensions for operating temperature from 150°C to 400°C (S0, S1, S2, S3, S4, S5) are produced. Delivery of stabilized bearings should be discussed in advance.
