FAG NJ2318-E-XL-M1A-C4 CYLINDRICAL ROLLER BEARING

This FAG cylindrical roller bearing with radial clearance C4 is designed for applications with large 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 ribs on the outer ring and one rib on the inner ring
• E: Optimized internal geometry for increased radial load capacity
• XL: X-life identification for improved contact surfaces and a longer service life
• M1A: Two-piece brass cage, flange-guided
• C4: Radial clearance greater than C3, suitable for large thermal expansions and very tight fits

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

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

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

Applications:
FAG cylindrical roller bearings in C4 execution are particularly designed for operating environments with high or fluctuating temperatures and 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 cause dimensional variations that are absorbed by the C4 clearance without creating excessive preload. The brass cage M1A and X-life technology ensure consistently high performance even under recurring thermal stresses. In mechanical drive trains and gearboxes of large machines, the NJ design provides reliable axial guidance of the shaft in one direction while preserving the necessary freedom of movement for thermal expansions.