SKFNNU4944BC4Cylindrical Roller Bearing – Straight Bore, 220 mm ID, 300 mm OD, 80 mm Width, 2 Row, C4 Internal Clearance

Product Description

What this part is

SKF NNU 4944 B/C4 double-row cylindrical roller bearing. Bore 220 mm, outside diameter 300 mm, width 80 mm. Series: NNU 49. Bore form: straight. Machined brass cage, open on both faces. Country of origin: Germany.

Decoding the designation

NNU: double row of cylindrical rollers. B: SKF design variant within the NNU 49 series. C4: internal clearance greater than C3, a clearance-set execution rather than a preloaded one. The absence of a K means the bore is straight, so the bearing seats on a cylindrical journal.

Published ratings

Dynamic load rating: 560 kN (126,000 lbf). Static load rating: 1,220 kN (274,000 lbf). Limiting speed: 2,800 rpm. Operating range: −30 °C to 150 °C. Mass: 32.5 lb.

What these specs mean in practice

Line contact between roller and raceway gives a cylindrical roller bearing several times the radial capacity of a ball bearing on the same envelope, and two rows double the load-carrying length. The static figure standing above the dynamic figure is normal for this family: the rollers spread the load over a long contact line, so permanent raceway deformation takes a very high load. C4 clearance leaves room for thermal growth of the inner ring and for a tight interference fit on the shaft, which is what heavy mill, gearbox and press positions run.

Quantity and configuration

One bearing. Unit quantity: 1 Pc.

Fitting notes

Straight 220 mm bore, mounted directly on a cylindrical shaft seat. Radial load only; a cylindrical roller bearing of this design locates the shaft radially and axial location comes from a second bearing in the arrangement.

Interchange guidance

Same-envelope designations from other makers: FAG NNU4944-S-K-M-SP (related size, tapered bore), NSK NNU4944MBKR (related size, tapered bore), NTN NNU4944. Searchable forms: NNU4944BC4, NNU 4944 B C4, NNU-4944-B-C4, NNU4944.