Cylindrical Roller Bearings
Cylindrical roller bearings (CRBs) have a simple structure of cylindrical rollers in linear contact with the raceways. They offer high load capacity under primarily radial loads. Low friction between the rollers and ring ribs makes these bearings suited for high speed rotation.
Single-row bearings are designated as NU, NJ, NUP, N, or NF, while double-row bearings are designated as NNU or NN, depending on if side ribs are used. All types allow the inner and outer rings to be separated.
Some CRBs used as free-end bearings have no ribs so that the rings can move axially relative to each other. When the inner or outer ring has ribs on both sides and the other ring has a rib on one side, these bearings can take some axial load in one direction.
Double-row cylindrical roller bearings have high radial rigidity and are used primarily for the main shafts of precision machine tools. Cages are typically made of pressed steel or machined brass, but molded polyamide resin cages are used for some models.
NSK offers a variety of CRB types to suit your needs.
Types of Cylindrical Roller Bearings
NU, N, NNU, NN: Suitable as free-end bearings.
NJ, NF: Can sustain limited axial loads in one direction.
NH, NUP: Suitable as fixed-end bearings. NH types are comprised of a NJ-type CRB with a HJ-type L-shaped thrust collar.
EW Series CRBs feature high load capacity with high-performance pressed steel cages suitable for a wide variety of industrial applications.
EM Series CRBs feature high load capacity with machined, one-piece brass cages suitable for all kinds of industrial applications.
ET Series high load capacity CRBs with polyamide resin cages support continuous operation at temperatures ranging from -40 to 120°C.
(Please contact NSK for operation at temperatures of 100 °C or higher in environments with gear oils, flame-resistant hydraulic oils, or synthetic ester-based oils.)
Full-complement cylindrical roller bearings have no cage to allow the maximum number of rollers possible, greatly increasing load capacity. However, this makes their high-speed performance slightly lower than that for bearings with cages.
Open single- and double-row types are mainly used in general industrial machinery with low speeds and high loads. Shielded double-row types are used primarily for crane sheaves.
Specially designed for the tough environments facing crane sheaves, these bearings offer excellent durability and resistance to outdoor elements. Easy to assemble and relubricate, CRBs for sheaves are designed with maintenance in mind.
- Excellent sealing
Contact seals significantly reduce the entry of water and foreign matter.
- High load capacity
These bearings can take the significant radial and thrust loads present in crane sheaves.
A phosphate coating improves resistance to rust and corrosion.
- Easy grease replenishment
Lubrication holes supplied in the inner ring allow for grease in sealed types to be easily refilled and replaced.
- Fewer mounting parts
Equipped with a locating snap ring, using these specialized bearings reduces the number of surrounding components, allowing for a more economical sheave structure.