SKF NU 312 ECP Cylindrical Roller Bearing, 60 mm Bore

A free-axial-displacement roller bearing for high radial loads at speed

The SKF NU 312 ECP is a single row cylindrical roller bearing of the NU design. The outer ring has two integral flanges and the inner ring has none, so the inner ring with its rollers and cage can slide axially relative to the outer ring in both directions. That makes the NU a classic non-locating bearing: it takes high radial load, absorbs thermal growth of the shaft and does not fight the locating bearing that fixes the shaft axially.

With a 60 mm bore, 130 mm outside diameter and 31 mm width, the bearing is used in gearboxes, large electric motors, pumps, compressors and fan drives. SKF describes the Explorer single row cylindrical roller bearing as offering higher radial load capacity, reduced friction and up to three times longer service life than earlier designs in its leaflet.

Technical specifications

What the designation tells you

NU names the flange arrangement. The SKF leaflet refers to EC design bearings, meaning the optimised internal geometry behind the higher load capacity, and the final letter of ECP indicates the cage type, so confirm the cage on SKF data where it matters to you. The product page lists an angle ring HJ 312 EC as an associated product, which is the accessory that turns an NU bearing into a unit that locates the shaft axially in one direction.

Because the rings separate, the inner ring can be fitted with an interference fit on the shaft and the outer ring in the housing, which simplifies mounting and dismounting of heavy machines. SKF notes that the optimised roller end and flange geometry reduces friction and heat, and the leaflet gives a logarithmic contact profile that limits edge stress.

Design and ordering notes

A minimum radial load is needed to keep the rollers in correct rolling motion; SKF gives a minimum load factor kr of 0.15 for this bearing, and the limiting value e is 0.2 with factor Y 0.6 for the equivalent load calculation. Permissible axial displacement of the inner ring relative to the outer ring is up to 2.1 mm in the table, so the housing shoulder must leave room for that movement.

Confirm the clearance class, the cage preference and whether the shaft needs an angle ring. For other bearings used in the same duties see Electric Motors, and the SKF TLSD automatic lubricator as a lubrication accessory for bearings in motors and pumps.

Documents and quotation

The attached SKF leaflet covers the features of the Explorer single row cylindrical roller bearing range; dimensions and ratings in the table come from the SKF product page for the NU 312 ECP. Send the designation and quantity to Seven Star LLC, an independent supplier in Muscat, to receive a quotation.