NTN NU307EAT2X CYLINDRICAL ROLLER BEARING

Suited to high radial loads and for use as floating or fixed bearings, 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, operating noise, speed, capacity, etc.

NTN cylindrical roller bearings of the ULTAGE™ series are a benchmark solution for applications with high radial loads and sustained rotational speeds. The optimized internal design of this range provides increased load capacity within the same envelope as standard series, with extended maintenance intervals as a result.

Decryption:
- NU: single-row bearing with two shoulders on the outer ring and none on the inner ring; separable inner ring.
- EA: denotes NTN's ULTAGE™ series; external envelope dimensions are maintained, but internal specifications are optimized (increased diameter, length and number of rollers).
- T2X: glass-fiber reinforced polyamide cage.

Characteristics:
These NU-type bearings are built around an outer ring with two shoulders and an inner ring without a shoulder. This configuration allows the outer-ring–rollers–cage assembly to be separated from the inner ring, simplifying mounting and dismounting. Axial displacement occurs by sliding on the shaft seats, making these bearings a natural choice for floating bearings.

The ULTAGE™ series retains the envelope dimensions of standard bearings while incorporating larger-diameter rollers in greater numbers. The profile of the roller generatrix is optimized to limit stress concentrations at the contact ends. These internal developments result in increased dynamic load capacity and an improved permissible speed by 20 % compared with the standard, under oil lubrication. ULTAGE™ type rings are not interchangeable with standard series rings due to a different inscribed circle diameter.

The cage in glass-fiber reinforced polyamide 66 offers good mechanical strength, heat resistance and low wear. This material also provides some flexibility during assembly, particularly useful on constrained geometries.

Maintenance:
Open bearing: lubrication (grease or oil) must be adapted to service conditions. The ULTAGE™ series benefits from extended re-greasing intervals. Shaft/housing mounting tolerances must comply with NTN recommendations to maintain the residual clearance within the permissible range. In operation, monitor temperature, vibrations and noise. Permissible misalignment is 1/500 mm/mm.

Key advantages:
- Increased radial load capacity in the same envelope, without changing existing bore dimensions.
- Separable inner ring, facilitating mounting and replacement without full shaft removal.
- Free axial displacement that absorbs thermal expansion without stressing other components of the assembly.
- Extended maintenance intervals thanks to the technical improvements of the ULTAGE™ series.

Applications:
These NTN bearings are used as floating bearings, paired with a fixed bearing (type NJ or NUP) to form a complete assembly. They are suitable for industrial drives, long-shaft reducers, gearboxes, electric motors and motor-pump units, wherever the shaft is subject to thermal expansion or axial displacement. The robustness of the ULTAGE™ profile and the polyamide cage also make them suitable for equipment with variable loads or frequent starts.