NJ2308EM Cylindrical Roller Bearing Axial Load For Industrial Motor / Automotive System

NJ2308EM Cylindrical Roller Bearing For Industrial Motors & Automotive Systems

The NJ2308EM cylindrical roller bearing is renowned for its precise design, durability, and high performance, suitable for various modern industrial applications. This article will briefly introduce its design features, performance, materials, applications, and installation and maintenance points to help you quickly understand its key role in improving mechanical efficiency and reliability.

I. Design and Structure

Inner Ring and Outer Ring

The inner ring is precision-machined with an almost mirror-like surface, perfectly fitting a shaft with a diameter of 40mm to ensure smooth power transmission and reduce the risk of slippage. The outer ring focuses on sturdiness, capable of withstanding large radial loads, with an outer diameter of 90mm and a width of 33mm, achieving high load-bearing capacity in limited space.

The inner ring has double ribs on one side, while the outer ring has no ribs. This unique design enables it to bear both large radial loads and a certain amount of unidirectional axial load. The double ribs on the inner ring effectively guide the cylindrical rollers, ensuring their correct positioning and rotation under complex dynamic loads, thus ensuring stable operation of the bearing.

Rolling Elements and Cage

The core components are a row of refined cylindrical rollers, made of high-grade bearing steel, processed through strict craftsmanship, with a surface roughness of less than Ra0.1μm, which greatly reduces rolling friction and improves energy efficiency and operational stability. The cylindrical shape, combined with precisely designed raceways, distributes loads evenly through line contact, enhancing radial load-bearing capacity.

The cage is usually made of brass (CuZn37), which has both excellent thermal conductivity and mechanical strength. During medium and high-speed operation, it can effectively dissipate heat to prevent overheating; at the same time, it maintains the spacing between rollers to avoid mutual interference and collision during rotation, guiding the rollers to move along the raceways, and improving the overall performance and reliability of the bearing.

Sealing Structure (Optional)

Some models are equipped with optional sealing devices to adapt to different environments. In dusty or humid environments, nitrile rubber contact seals can be used, which closely fit the inner ring to block contaminants and extend service life; for high-speed scenarios, non-contact labyrinth seals are suitable, allowing a rotational speed of up to 6000rpm, reducing friction while providing certain protection.

II. Key Parameters

III. Performance Advantages

High Radial Load-Carrying Capacity

The single-row cylindrical roller design and optimized contact geometry give it a basic dynamic load rating of 70.5kN and a static load rating of 65.5kN, which can easily handle large radial loads in various industrial applications, such as motors of large conveying systems and gearboxes of medium and heavy machinery, and is not prone to fatigue failure when bearing loads for a long time.

Axial Load Adaptability

The design of double ribs on one side of the inner ring enables it to bear a certain amount of unidirectional axial load. In scenarios with axial forces (such as some motors and specific industrial machinery), it can reduce stress concentration on the shaft and other components, extend the service life of the equipment, and improve reliability.

Low Friction and High-Speed Performance

Precision-ground rollers and smooth cages result in a friction coefficient as low as 0.002, reducing energy consumption and enabling high-speed operation. The limiting speed under grease lubrication is 4500rpm, and under oil lubrication it reaches 6000rpm, suitable for equipment requiring high speed and low friction, such as machine tool spindles and high-speed fans.

Good Wear Resistance

The rings and rollers are made of high-carbon chromium bearing steel (GCr15), with a hardness of HRC60-65 after heat treatment. The surface is specially treated to enhance wear resistance, and can maintain performance for a long time in high-load, high-speed and abrasive environments.

IV. Material Quality

Material of Rings and Rollers

High-purity bearing steel (GCr15) is used, and vacuum degassing process is adopted to remove internal pores and inclusions, improving density and mechanical properties. The rollers undergo cold heading, high-temperature tempering and other processes, with a uniform internal structure and impact toughness exceeding 10J/cm², enhancing fatigue resistance and ensuring long-term reliable operation.

Cage Material

The brass (CuZn37) cage has good thermal conductivity, which can efficiently dissipate heat to avoid high temperature affecting performance; its mechanical strength is sufficient to withstand centrifugal force and roller 作用力 during operation, ensuring correct alignment and movement of the rollers.

V. Application Fields

Industrial Machinery

Widely used in drive shafts of large lathes to support axial and radial loads during cutting; in rollers and pulleys of heavy-duty conveying systems, its load-bearing capacity ensures smooth conveying, directly affecting production efficiency.

Electric Motors

Suitable for medium and high-power motors, bearing radial forces generated by rotating components, compensating for axial movement caused by thermal expansion, etc. Its low friction and high-speed performance improve motor energy efficiency and service life.

Automotive Industry

Can be used in vehicle differentials to cope with complex radial and axial loads, ensuring smooth power transmission; also applicable to water pumps of large internal combustion engines, working reliably in high-temperature, humid and vibrating environments to ensure the operation of the cooling system.

VI. Installation and Maintenance

Installation requires a hydraulic press or special tools to ensure precise fitting and avoid misalignment or damage to components; when installing on a tapered shaft, adjust the position and preload through a lock nut to improve rigidity and reduce vibration.

In terms of lubrication, lithium-based grease is selected for general applications, with a filling amount of 1/3-1/2 of the internal space of the bearing; oil lubrication (ISO VG 32 or 46) is suitable for high-speed or high-temperature scenarios, and the oil pressure of the forced lubrication system is maintained at 0.1-0.3MPa.

Regular maintenance needs to monitor the bearing temperature (normally not exceeding 70℃), check for abnormal vibration and noise, and troubleshoot in time; use a puller for disassembly to avoid damaging the shaft and bearing seat, and early detection of hidden dangers can reduce downtime and maintenance costs.

VII. Conclusion

The NJ2308EM cylindrical roller bearing integrates high strength, excellent load-bearing capacity and wide adaptability, and can operate stably under various working conditions. It is an indispensable key component in modern mechanical engineering, helping various industries improve efficiency and development.