319434-2LS Cylindrical Roller Bearing (170x230x80mm)

About This Type

Cylindrical roller bearings carry high radial loads at high speeds; line contact between rollers and raceways provides much higher radial capacity than a ball bearing of the same size. Typical applications include electric motors, gearboxes, pumps, traction motors and — in double-row designs — machine-tool spindles and rolling mills.

The rib configuration determines the axial behaviour. NU and N designs allow free axial displacement between shaft and housing, so they serve as the floating end where thermal expansion must be absorbed. NJ locates the shaft in one axial direction; NUP — an NJ with a loose rib washer — locates it in both directions and serves as the locating end. Full-complement designs (NCF, SL, NNCF …) fit the maximum number of rollers for the highest radial ratings, at the cost of limiting speed, while the double-row NN and NNU designs sacrifice compactness for rigidity. Unlike tapered roller bearings, cylindrical roller bearings use the CN/C2/C3/C4 clearance groups; the group is selected on the basis of the fits and the temperature gradient.

Inner and outer rings are separable on NU, N, NJ and NUP designs, so each ring can be mounted with its own interference fit — an advantage in tight assemblies. On NUP bearings, the loose rib washer must be fitted on the correct side; on floating-end NU/N arrangements, the fit must prevent creep without blocking axial displacement. Never use an NU or N bearing to locate a shaft axially.