NACHI N321C3 Cylindrical Roller Bearing

NACHI N321C3 Cylindrical Roller Bearing

The NACHI N321C3 is a precision cylindrical roller bearing (N – Inner Ring Without Ribs) designed for high radial load capacity at moderate to high speeds. With a bore diameter of 105 mm, outer diameter of 225 mm, and a width of 49 mm, this bearing conforms to ISO dimension standards and is a direct interchange for equivalent cylindrical roller bearings from other manufacturers.

Design & Construction

Manufactured by NACHI – one of Japan’s leading bearing producers – the N321C3 is precision-ground from high-carbon chromium bearing steel (AISI 52100 / JIS SUJ2), heat-treated to achieve optimum hardness and fatigue resistance. The line contact between rollers and raceways provides a much larger contact area than ball bearings of the same size, resulting in substantially higher radial load capacity. The N design features a ribless inner ring and an outer ring with two integral ribs. This configuration allows free axial displacement of the shaft relative to the housing, making it ideal for the non-locating bearing position in arrangements that require thermal expansion. Supplied with C3 internal radial clearance (greater than Normal/CN), which is recommended for applications involving elevated operating temperatures, interference fits on both rings, or where thermal expansion of the shaft may reduce internal clearance during operation.

Performance

Rated for a basic dynamic load capacity of 340.0 kN and a static load capacity of 385.0 kN, this bearing delivers exceptional radial load-carrying ability and long calculated service life under correct operating conditions. Permissible speeds reach 2,600 rpm with grease lubrication and 3,200 rpm with oil lubrication. Cylindrical roller bearings are inherently separable – the inner ring with roller and cage assembly can be mounted independently from the outer ring, simplifying installation and maintenance in many applications.

Typical Applications

• Electric motors and generators
• Gearboxes, reducers, and transmission assemblies
• Pumps, compressors, and turbines
• Machine tool spindles and precision equipment
• Rolling mill and heavy industrial machinery
• Wind turbine drivetrain components
• Railway axlebox and traction motor bearings
• Mining, quarrying, and construction equipment
• Paper and steel mill processing equipment
• General industrial and workshop machinery