Description

The NTN NU308 is a high-performance single row cylindrical roller bearing, designed to handle substantial radial loads with precision, stability, and durability. Engineered and manufactured by NTN Corporation, one of the world’s leading bearing manufacturers, the NU308 is part of the NU cylindrical roller series, known for its advanced load-carrying capabilities and reliable performance in high-speed, heavy-duty applications. This bearing is commonly used in a wide range of mechanical systems, including gearboxes, electric motors, pumps, compressors, and industrial machinery.

The NU308 design features cylindrical rollers arranged in a single row, which are guided by integral flanges on the outer ring. The inner ring has no flanges, allowing the bearing to accommodate axial displacement of the shaft relative to the housing in both directions. This makes the NU308 particularly well-suited for use in applications where thermal expansion and shaft growth must be managed without introducing axial loads on the bearing.

Key Dimensions and Specifications:

Bearing Type: Single Row Cylindrical Roller Bearing
Model: NU308
Inner Diameter (Bore): 40 mm
Outer Diameter: 90 mm
Width (Thickness): 23 mm
Approximate Weight: 0.76 kg
Limiting Speed (Grease): Up to 8,000 RPM (varies by lubrication and application)
Construction: Separable (outer and inner ring can be mounted independently)

Design and Performance

The cylindrical roller design offers a larger contact area compared to ball bearings, which significantly improves the bearing’s ability to support high radial loads while maintaining smooth, low-friction rotation. This makes the NU308 an excellent choice for medium- to high-load applications operating under continuous or heavy-duty conditions.

One of the core advantages of the NU308 bearing is its ability to accommodate axial displacement. Since the inner ring lacks flanges, the shaft can expand and contract without imposing stress on the bearing. This is especially useful in applications involving high temperatures or long shafts, where thermal expansion is common.

The roller and cage assembly of the NU308 ensures uniform load distribution, reduced heat generation, and low rolling resistance, even at high speeds. The steel cage is engineered to withstand centrifugal forces and deliver stable, vibration-free performance in dynamic environments.

Construction and Materials

NTN uses premium-quality bearing steel that undergoes precision heat treatment to provide outstanding fatigue resistance, dimensional stability, and hardness. The rollers are machined and finished to tight tolerances, ensuring uniform rotation and consistent performance over long operating periods.

The bearing is typically supplied without seals or shields, meaning it must be properly lubricated and protected within the housing assembly. Depending on the specific application, the NU308 can be used with grease or oil-based lubrication systems, both of which contribute to long service life and reduced maintenance.

Applications

Thanks to its high radial load capacity and flexibility for axial displacement, the NTN NU308 is widely used in:

Gearboxes and transmission systems
Electric motors and generators
Machine tool spindles
Pumps and compressors
Steel, paper, and cement processing machinery
Heavy-duty construction and mining equipment

Its design supports high-speed operation and continuous duty cycles, making it suitable for industries that demand long-lasting, reliable performance with minimal maintenance.

Installation and Interchangeability

The separable construction of the NU308 simplifies installation and disassembly. The inner and outer rings can be mounted independently, which allows for easier alignment during assembly or servicing.

The NU308 complies with ISO and DIN standards, ensuring full interchangeability with bearings from other reputable manufacturers such as SKF, FAG, NSK, and Timken.

Summary

The NTN NU308 Single Row Cylindrical Roller Bearing is a rugged, high-capacity radial bearing with a 40mm bore, 90mm outer diameter, 23mm width, and 0.76 kg weight. Engineered for high-speed and heavy-load applications, it features cylindrical rollers, an open design for axial movement, and durable steel construction. Ideal for gearboxes, motors, and heavy-duty industrial machinery, the NU308 delivers long service life, reduced friction, and reliable operation under challenging conditions.

1VP Store
1Vendor Platform