Cylindrical Roller Bearings

These designations indicate different rib (flange) configurations that determine how the bearing handles axial loads and shaft displacement. NU type has ribs on the outer ring only, allowing the inner ring to move axially in both directions, ideal for non-locating (free-end) positions. NJ type adds a single rib to the inner ring, providing single-direction axial location. NUP type includes a detachable flat ring on the inner ring alongside the NJ rib arrangement, enabling bidirectional axial location, suitable for locating (fixed-end) positions. N type has ribs on the inner ring only, and NF type has a single rib on the outer ring with double ribs on the inner ring for single-direction axial location.

Cylindrical roller bearings with ribs on both inner and outer rings (NJ, NUP, NF types) can support axial loads in addition to their primary radial load. The permissible axial load depends on the bearing's static load rating (C0r), the radial load present, rotational speed, and lubrication conditions. As a general guideline, the bearing operates normally when the axial-to-radial load ratio (Fa/Fr) remains below 0.4. When Fa/Fr is less than 0.13, the axial load's effect on bearing life is negligible. For applications combining moderate axial loads with high radial loads, NUP type provides bidirectional axial retention in a single bearing.

BOM manufactures cylindrical roller bearings from standard tolerance through high-precision grades. For general industrial applications such as electric motors and gearboxes, normal tolerance with CN clearance is standard. For machine tool spindles requiring improved running accuracy, tighter tolerance grades reduce radial and axial runout. For CNC machining centers, grinding spindles, and precision instrument spindles where rotational accuracy directly affects workpiece quality, the highest precision grades are available. Higher precision grades require correspondingly higher machining accuracy of the mating shaft and housing bore. Our engineering team can advise on the appropriate fit and tolerance for your application.

Cylindrical roller bearings use line contact between rollers and raceways, providing substantially higher radial load capacity and rigidity than deep groove ball bearings of the same bore size. The higher rigidity minimizes shaft deflection under load, critical in gearboxes and machine tool applications where gear alignment or machining accuracy depends on bearing stiffness. Cylindrical roller bearings are the preferred choice when the application involves primarily radial loads, requires high stiffness, and demands high rotational speed capability. Multiple rib configurations give the system designer full control over shaft axial behavior (locating, non-locating, or bidirectional retention) within a single bearing series.

Yes. BOM manufactures custom cylindrical roller bearings across the full specification range, including non-standard bore, OD, and width dimensions; modified rib configurations for specialized axial location requirements; alternative ring, roller, and cage materials for high-temperature, corrosive, or electrically insulating environments; specialized surface coatings; and complete bearing architecture redesign for integrated or application-specific solutions. Our engineering team provides full support from design consultation through prototype validation and series production.