FAGNNU4922SMSPDouble Row Cylindrical Roller Bearing – Straight Bore, 110 mm ID, 150 mm OD, 40 mm Width, 2 Row, SP Super Precision, Machined Brass Cage, C1 Clearance

Product Description

What this part is

FAG NNU4922SM.SP super precision cylindrical roller bearing. Double-row, non-locating design, 110 mm bore x 150 mm outside diameter x 40 mm width. Separable, with a machined cage. Carton designations: NNU4922SM.SP, NNU4922S.M.SP, NNU-4922-S-M-SP, NNU4922. The outer ring carries a lubrication groove and radial feed holes, the FAG equivalent of the W33 marking.

Decoding the designation

Series: NNU49. Design: NNU, double row with ribs on both the inner and the outer ring. Bore Type: straight cylindrical. Cage Type: machined. Cage Material: brass. Tolerance Class: SP, Schaeffler’s special precision grade for spindle bearings. Locating feature S: lubrication holes and a lubrication groove in the outer ring. Radial Internal Clearance: C1, Group 1, tighter than C2.

What these specs mean in practice

A double-row cylindrical roller bearing of this section carries very high radial load in a short axial space, which is why the NNU49 series is used as the front bearing on machine tool spindles. Basic dynamic load rating, radial: 132,000 N. Basic static load rating, radial: 270,000 N. Fatigue load limit, radial: 35,000 N. Limiting speed with grease: 5,400 rpm. Limiting speed with oil: 6,300 rpm. Operating range: -30 °C to 150 °C. Weight: 2.04 kg (4.50 lb). The C1 clearance group gives tight radial location and low runout under preload from the shaft fit.

Load direction and axial capacity

This is a non-locating bearing. It carries radial load only and permits axial displacement of 2 mm within the bearing, so the shaft is located axially by a second bearing elsewhere in the arrangement.

Quantity and configuration

One bearing. Separable: the outer ring with its roller and cage assembly parts from the inner ring, and both rings ship together.

Fitting notes

Straight cylindrical bore, mounted with an interference fit on a cylindrical shaft seat. Shaft shoulder diameter: 122 mm to h12. Housing shoulder diameter: 139 mm to H12. Inner ring raceway diameter: 123 mm. Maximum recess radius: 1 mm. Minimum chamfer dimension: 1.1 mm. Lubrication groove width: 6.5 mm. Lubrication hole diameter: 3.2 mm. Radial internal clearance on an NNU is set by the amount of interference on the cylindrical seat.

Interchange guidance

Same-specification equivalents: SKF NNU 4922 SP, NSK NNU4922. The tapered-bore execution of this envelope, FAG NNU4922SK.M.SP, is a related size: it mounts directly on a 1:12 tapered spindle journal instead of a cylindrical seat.