FAG NJ2308-E-XL-M1A-C4 CYLINDRICAL ROLLER BEARING

This FAG cylindrical roller bearing with radial clearance C4 has been designed for applications with significant thermal expansions or very tight fits. The X-life version and the increased radial load capacity make it a suitable solution for demanding heavy-duty applications.

Explanation:
• NJ: Single-row bearing with two flanges on the outer ring and one flange on the inner ring
• E: Optimized internal geometry for increased radial load capacity
• XL: X-life designation for improved contact surfaces and a longer service life
• M1A: Two-piece, rim-guided brass cage
• C4: Radial clearance larger than C3, suitable for significant thermal expansions and very tight fits

Characteristics:
The combination of an outer ring with two flanges and an inner ring with one flange defines the NJ design. It enables reliable axial guidance in one direction while simultaneously serving as a floating bearing in the opposite direction. For applications that require axial guidance in both directions, the bearing can be converted into a fixed bearing by installing an HJ angle ring (not included). The radial clearance C4, which is larger than C3, prevents excessive internal preload in very tight fits or pronounced thermal load cycles. The two-piece rim-guided brass cage M1A stabilizes the rolling elements and assists heat dissipation during operation. The contact surfaces optimized by the X-life manufacturing technology reduce stress peaks and ensure a more uniform load distribution on the raceways. The separable design facilitates assembly and maintenance operations. The inner ring can be mounted independently on the shaft, while the remaining part of the bearing is installed separately in the housing.

Maintenance:
Monitoring vibration and noise is an important indicator of bearing condition. Unusual changes may indicate raceway damage or contamination of the lubricant. Bearing temperature should also be checked regularly. A temperature increase that cannot be explained by operating conditions often indicates lubrication problems or an unsuitable bearing clearance. The C4 clearance provides increased tolerance to thermal expansions and tight fits. Nevertheless, during commissioning it should be verified whether the selected bearing clearance matches the actual installation and temperature conditions. Lubrication can be carried out with grease or oil depending on speed and temperature range. Re-lubrication intervals must be determined according to the actual loads and operating conditions. As this bearing is of an open design, appropriate measures to protect against dust and abrasive particles must be taken during all maintenance work. The separability of the inner ring makes the rolling elements more accessible during regular inspections. A visual inspection of the raceways and rollers enables early detection of fatigue signs, spalling or indentations before the bearing's function is impaired.

Strengths:
• The C4 clearance compensates for significant thermal expansions and is suitable for very tight fits.
• The separability of the inner ring reduces downtime during maintenance.
• The increased dynamic load capacity provided by the X-life design enables an extension of the nominal service life by more than 70 %.

Applications:
FAG cylindrical roller bearings in C4 design are particularly intended for applications with high or fluctuating operating temperatures as well as tight fits. In heavy industry, for example in the steel industry, foundries, paper mills or cement plants, such bearings are frequently used in gearboxes, rolling mills and rotating equipment exposed to strong temperature gradients. Industrial compressors and high-power drive systems are also typical application areas. Cold starts and load changes there lead to dimensional changes that are accommodated by the C4 clearance without causing excessive preload. The brass cage M1A and the X-life technology ensure consistently high performance, even under recurring thermal loads. In mechanical drivetrains and gearboxes of large machines, the NJ design provides reliable axial guidance of the shaft in one direction while at the same time maintaining the freedom of movement required for thermal expansions.