NTN NU207EAT2XC3 CYLINDRICAL ROLLER BEARING

Suited to high radial loads and to use as a non-locating (free) or locating (fixed) bearing, cylindrical roller bearings offer low friction and good rigidity. They are available in a wide range of designs and variants addressing specific conditions: heat, axial displacement, operational noise, speed, capacity, etc.

The NTN ULTAGE™ series groups cylindrical roller bearings whose internal specifications have been optimized to improve performance, extend service life and reduce maintenance intervals. The separability of the inner ring simplifies mounting and facilitates periodic inspections.

Decoding :
- NU: single row of rollers, outer ring with two shoulders, inner ring without shoulder. The outer ring, rollers and cage assembly is separable from the inner ring; for use as a non-locating (free) bearing only.
- EA: denotes NTN's ULTAGE™ series; rollers of larger diameter and in greater number than a standard type, optimized roller generatrix profile, increased load capacity at identical envelope dimensions.
- T2X: polyamide 66 cage reinforced with glass fibers; light, wear-resistant, economical, promotes ease of assembly.
- C3: internal radial clearance greater than normal; compensates for tight fits and thermal expansions in service.

Features :
NTN NU-type cylindrical roller bearings are the reference for non-locating (free) bearing applications. The outer ring has two shoulders that retain the rollers and the cage, while the inner ring, without a shoulder, allows free axial displacement in both directions. This separability simplifies mounting on long shafts and permits thermal expansion without axial constraint on the bearing.

The EA suffix identifies the ULTAGE™ series: the diameter, length and number of rollers have been increased compared with the standard type while retaining the external envelope dimensions. The generatrix profile of the rollers is optimized to better distribute contact stresses and limit pressure concentrations at edges. The permissible speed increases by 20% in oil lubrication compared with equivalent standard references.

The polyamide 66 cage reinforced with glass fibers (T2X) contributes to the lightness of the assembly and tolerates common mechanical loads. It offers good resistance to heat and wear.

The C3 internal clearance, greater than normal, compensates for tight fits and temperature rises in operation, thus reducing the risk of excessive internal preload.

Maintenance :
Bearings of this NTN cylindrical roller series are supplied ungreased: the choice and application of lubricant are the operator's responsibility. Oil lubrication is recommended for high speeds, grease lubrication is suitable for lower-speed or less accessible applications. Extreme-pressure additives of type S or P should be avoided with the T2X polyamide cage, particularly when operating temperature is high.

As with any open bearing, this series must be protected from contamination by seals or labyrinths fitted in the housing. When disassembling for inspection, the condition of the raceways, the surface of the rollers and the integrity of the cage should be checked. Any sign of pitting, flaking or deformation requires replacement of the affected element.

Key advantages :
- Increased radial load capacity at constant envelope: replacement of a standard bearing without modifying the housing.
- Free axial displacement: no parasitic axial load generated on the assembly in case of thermal expansion.
- Separability of the inner ring: independent mounting on a long shaft without risk of damage.
- Extended maintenance intervals thanks to ULTAGE™ internal specifications, reducing production line downtime.
- Permissible speed increased by 20% (oil lubrication) compared with the equivalent standard type.
- C3 clearance suited to marked thermal cycles and frequent starts, without risk of excessive preload.

Applications :
NTN NU-type cylindrical roller bearings are structurally intended for non-locating (free) supports, i.e. mounting points where the shaft must be free to move axially. This requirement is systematically found in two-bearing arrangements, where one bearing is fixed and the other free, to absorb dimensional variations due to temperature or manufacturing tolerances.

In power transmission mechanics, they equip industrial electric motors, speed reducers and general transmission gearboxes. The ability to run at high speed with good rotational accuracy makes them suitable for the high-speed shafts of these machines. Industrial pumps and process fans are also common applications, particularly when the mounting requires managing the expansion of a long horizontal shaft.

The C3 internal clearance makes them particularly relevant for equipment subject to frequent starts or significant thermal variations, such as construction machinery, cranes or production machines operating in alternating cycles.