NTN NU311EAT2X CYLINDRICAL ROLLER BEARING

Suitable for high radial loads and for use as a free or 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, operating noise, speed, capacity, etc.

NTN cylindrical roller bearings of the ULTAGE™ series represent 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.

Explanation :
- 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; standard limiting dimensions are retained, but internal specifications are optimized (roller diameter, length and number increased).
- T2X: glass-fiber reinforced polyamide cage.

Features :
These NU-type bearings are built around an outer ring with two shoulders and no shoulder on the inner ring. This configuration allows separation of the outer ring–rollers–cage assembly from the inner ring, simplifying mounting and disassembly. Axial displacement occurs by sliding on the seats, making these bearings a natural solution for free (floating) bearings.

The ULTAGE™ series retains the overall dimensions of standard bearings while incorporating larger-diameter rollers in greater numbers. The roller generating profile is optimized to limit stress concentrations at the contact edges. These internal developments result in increased dynamic load capacity and an improved allowable speed of 20% compared with the standard when lubricated with oil. ULTAGE™ type rings are not interchangeable with those of standard series due to the different inscribed circle diameter.

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

Maintenance :
Open bearing: lubrication (grease or oil) must be adapted to service conditions. The ULTAGE™ series benefits from extended relubrication intervals. Shaft/bore mounting tolerances must comply with NTN recommendations to keep 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 modifying existing bore dimensions.
- Separable inner ring, facilitating mounting and replacement without complete shaft removal.
- Free axial displacement absorbing thermal expansions 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 a free bearing, paired with a fixed bearing (type NJ or NUP) to form a complete arrangement. They are suitable for industrial drives, reducers with long shafts, 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 relevant for equipment with variable loads or frequent starts.