NTN NU224C3 CYLINDRICAL ROLLER BEARING

Suitable for high radial loads and for use in floating or fixed bearing arrangements, cylindrical roller bearings offer low friction and good stiffness. They are available in a wide range of designs and variants tailored to specific conditions: heat, axial displacement, operating noise, speed, capacity, etc.

With its two shoulders on the outer ring and an inner ring without a shoulder, the NTN NU bearing provides radial guidance of shafts in assemblies requiring axial mobility. The internal clearance C3 enhances its ability to operate under large thermal variation.

Explanation :
- NU : two shoulders on the outer ring, none on the inner ring; inner ring separable from the outer assembly.
- C3 : internal radial clearance greater than normal. Compensates for tight fits and thermal expansions; reduces the risk of excessive internal preload.

Characteristics :
The NU configuration features an outer ring with two shoulders and a smooth inner ring, which allows axial displacement of the shaft. The bearing operates exclusively as a floating bearing: no axial load can be transmitted or absorbed. The inner ring is separable from the rest of the bearing, facilitating installation and removal.
The line contact between the rollers and raceways distributes radial loads over a large area, enabling operation at high load and high speed levels. The C3 clearance limits the risk of internal preload during tight fits or temperature rises at startup.

Maintenance :
This NU cylindrical roller bearing is open, without integrated sealing. The lubricant must be chosen according to service conditions (speed, load, temperature) and renewed according to a defined maintenance schedule. The amount of grease must be kept under control: excess causes friction losses and a temperature rise.
Mounting should be carried out with appropriate tools — press or sleeve — without direct impact on the rolling elements. In the absence of a seal, the mounting environment must be clean and external sealing devices can be added if necessary. Regular monitoring of noise, vibration and temperature helps detect any early degradation.

Key benefits :
- Separable inner ring: facilitates installation and removal without extracting the entire bearing.
- Built-in floating bearing: absorbs axial thermal expansions without generating additional internal stresses.
- C3 clearance: reduces the risk of excessive preload in tight fits and during thermal startup cycles.

Applications :
The NTN NU bearing is used in assemblies where the shaft must be free to move axially, notably to accommodate differential thermal expansions between shaft and housing. It is generally paired with an opposite fixed bearing that takes up the axial loads.
Common applications include industrial electric motors, gearboxes, centrifugal pumps, fans and mechanical transmissions. Outdoor machines and equipment particularly benefit from the C3 clearance, which compensates for temperature differences between cold start and stabilized running.