FAG NJ2312-E-XL-M1A-C4 CYLINDRICAL ROLLER BEARING

This FAG cylindrical roller bearing with radial internal clearance C4 has been 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 designation for improved contact surfaces and longer service life
• M1A: Two-piece brass cage, flange-guided
• C4: Radial internal 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 configuration. It enables reliable axial guidance in one direction while allowing use as a floating bearing in the opposite direction. For applications that require axial guidance in both directions, the bearing can be converted to a fixed bearing by fitting an HJ locating ring (not included). The radial clearance C4, which is larger than C3, prevents excessive internal preload with very tight fits or 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 even load distribution on the raceways. The separable design simplifies mounting and maintenance. The inner ring can be mounted independently on the shaft while the remaining bearing part is inserted separately into the housing.

Maintenance:
Monitoring vibration 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 unsuitable internal clearance. The C4 clearance offers increased tolerance to thermal expansions and tight fits. Nevertheless, during commissioning it should be verified that the selected internal clearance matches the actual installation and temperature conditions. Lubrication can be performed with grease or oil depending on speed and temperature range. Re-lubrication intervals must be determined according to actual loads and operating conditions. As this bearing is of open design, appropriate measures to protect against dust and abrasive particles must be taken during all maintenance work. Because the inner ring is separable, the rolling elements are more accessible during regular inspections. A visual inspection of the raceways and rollers enables early detection of signs of fatigue, spalling or indentations before bearing function is impaired.

Strengths:
• The C4 internal 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 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 service in environments with high or fluctuating operating 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 steep temperature gradients. Industrial compressors and high-power drive systems are also typical application areas. Cold starts and load changes there cause dimensional changes that the C4 clearance absorbs without creating excessive preload. The brass cage M1A and the X-life technology provide consistently high performance even under recurring thermal stress. In mechanical drive trains and gearboxes of large machines, the NJ design ensures reliable axial guidance of the shaft in one direction while maintaining the freedom of movement required for thermal expansions.