Four-Row Tapered Roller Bearings
The performance of four-row taper roller bearings are similar to a pair of double-row tapered roller bearings and have a higher load capacity, but the limiting speed is comparably lower. These are mainly used on the roll necks of rolling mill equipment. All four-row bearings are supplied as pre-set matched assemblies with all components identified to ensure correct installation sequence.
Most of the four-row tapered roller bearings supplied by NPB are designed based on two basic type TQO and TQI. The difference is the configuration or arrangement of the rollers and cage assemblies and the number of inner rings and outer rings. We can also supply bearings with tapered cones and sealed bearings according to customer’s requirement. However, TQO bearings are used almost exclusive.
Bearings with TQO configuration
The bearings with TQO configuration have two inner ring with double rollers and cage assemblies., two single row outer rings and a double row outer ring. Both the inner rings and outer rings are separated with spacers. The lubrication holes are machined on outer ring spacers, and the slots in the inner ring spacer permit the lubrication to flow from the bearing chamfer to the roll neck. The spacers are hardened to minimize face wear.
Bearing with TQI configuration
Bearings with TQI configuration have two paired rows of rollers and cage assemblies arranged back-to-back。 The inner rings consist of a double row inner ring and two single row rings, and there are two double row outer rings that separated with a spacer. Both the outer ring and spacer have lubrication holes. Their use is limited, being primarily where high stiffness is required and considerable tilting moments have to be accommodated. The bearings can be mounted with an interference fit on the roll necks as there is a tapered bore..