NTN NU310EAT2XC3 CYLINDRICAL ROLLER BEARING

Suited to high radial loads and for use in free or fixed bearing arrangements, cylindrical roller bearings feature 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 ULTAGE™ series from NTN 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 assembly and facilitates periodic inspections.

Breakdown :
- NU : one row of rollers, outer ring with two shoulders, inner ring without shoulder. The outer-ring, rollers and cage subassembly is separable from the inner ring; for free-bearing use 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 with identical external dimensional envelope.
- T2X : glass-fiber-reinforced polyamide 66 cage; lightweight, wear-resistant, economical, promotes ease of assembly.
- C3 : internal radial clearance greater than normal; compensates tight fits and thermal expansions in service.

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

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

The glass-fiber-reinforced polyamide 66 cage (T2X) contributes to the lightness of the assembly and withstands common mechanical stresses. 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 :
Cylindrical roller bearings of this NTN series are supplied without grease: selection and application of lubricant are the operator's responsibility. Oil lubrication is recommended for high speeds, while grease lubrication is suitable for slower or less accessible applications. Extreme-pressure additives of type S or P should be avoided with the T2X polyamide cage, particularly at elevated operating temperatures.

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

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

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

In power transmission machinery, they equip industrial electric motors, speed reducers and general gearboxes. Their 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 installation must manage the expansion of a long horizontal shaft.

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