FAG NJ2314-E-XL-TVP2-QP51-C4 CYLINDR ROLLER BEARING

This FAG cylindrical roller bearing was developed for applications with high radial loads and severe vibrations. It combines profiled raceways, a lightweight polyamide cage and increased internal radial clearance in a single design.

Explanation:
• NJ: Single-row bearing with one flange on the inner ring side and two flanges on the outer ring
• E: Version with increased radial load capacity compared to the standard design
• XL: FAG X-life designation; higher dynamic load capacity, longer service life and lower friction
• TVP2: Solid window-type cage made of glass-fiber reinforced polyamide PA66
• QP51: Crowned raceways on the inner and outer ring; improved load distribution under extreme vibrations
• C4: Radial internal clearance greater than C3

Features:
The crowned QP51 raceway profile is the central feature of this bearing. The raceways have a slight crowning on both the inner and outer ring. This causes contact forces to be distributed more evenly under severe vibrations or slight shaft deflection. In contrast to a standard cylindrical roller bearing, where local stress peaks can rapidly reduce life under dynamic loads, the QP51 profile reduces these stress concentrations while still providing sufficient load-carrying capacity for the intended applications. The solid TVP2 cage made of glass-fiber reinforced polyamide PA66 reduces rotating mass and thus allows faster acceleration and braking. The X-life design is based on manufacturing technologies that improve the surface quality and homogeneity of the raceways. This optimized surface condition reduces internal friction, limits heat generation and reduces stress on the lubricant. As a result the dynamic basic load rating increases, which extends the nominal life under the same operating conditions. The radial internal clearance C4, which is larger than C3 and therefore also larger than the normal clearance CN, protects the rolling elements during strong thermal expansion or in press fits with high fit-induced stresses. In operation it prevents unintended preload of the bearing when the inner ring expands due to temperature. Furthermore, the separable design of the NJ series allows the separation of the inner ring from the assembly of outer ring, rollers and cage. This facilitates both assembly and disassembly of the bearing.

Maintenance:
This cylindrical roller bearing is supplied as an open bearing. The lubricant must therefore be carefully selected and renewed regularly according to actual operating conditions. Lubrication is of crucial importance. The amount of lubricant must be correctly dosed, and the lubricant used must be compatible with the TVP2 polyamide cage, whose temperature resistance is guaranteed up to 120 °C. Above this temperature the cage begins to age, significantly shortening the bearing life. The choice of lubricant is therefore decisive for the cage durability. In heavily vibrated applications it should be verified whether the chosen cage design corresponds to the actual dynamic loads. If an MPAX solid brass cage was originally specified, it must under no circumstances be replaced by a TVP2 plastic cage. Condition monitoring should include multiple parameters. Vibration and noise are important indicators of bearing condition. A sudden increase in vibration level can indicate incipient raceway damage or lubricant deficiency. Operating temperature should also be checked regularly, particularly to ensure that the C4 internal clearance matches the actual thermal conditions of the application. A bearing operated well below its intended temperature range with C4 internal clearance can exhibit excessive clearance and cause impact loads on the rolling elements. During disassembly the separable design facilitates inspection. The inner ring remains on the shaft, so the inner and outer raceways as well as the rollers can be inspected separately. Signs of spalling, indentation or localized wear should always lead to replacement of the bearing.

Strengths:
• Resistant to extreme vibrations: The crowned QP51 profile distributes contact forces evenly and reduces stress peaks that can lead to premature microcracking.
• Quick disassembly: The inner ring remains on the shaft, eliminating extensive removal work and reducing downtime.
• Energy-efficient: The X-life surface quality reduces internal friction and heat generation, thereby lowering the machine's energy consumption.
• Low rotational mass: The TVP2 cage made of reinforced polyamide reduces rotational mass and improves start/stop behavior.
• Compact design with the same performance: The E version increases radial load capacity at unchanged dimensions, without requiring changes to existing bearing seats.

Applications:
This bearing is intended for a very specific field of use: machines and industrial plants where radial vibration loads are so high that standard bearings reach their fatigue limit prematurely. The choice of a QP51 profile is normally made after technical analysis by a specialist when the service life of a standard bearing is insufficient. Typical applications of this bearing family include industrial vibrators, in particular formwork or concrete compactors, where the shaft can deflect under cyclic dynamic loads. In such applications the outer ring with two flanges ensures axial guidance in one direction, while the crowned raceway profile accommodates the effects of dynamic misalignment without concentrating loads at the roller ends. Furthermore, this bearing is suitable for all mechanisms exposed to recurring impact loads or radial vibrations.