NSK7224CTDULP4Super-Precision Angular Contact Bearing – 120 mm ID, 215 mm OD, 40 mm Width, Open, 15° Contact Angle, Matched Duplex Pair

Product Description

What this part is

NSK 7224CTDULP4 super-precision angular contact ball bearing. Bore: 120 mm. Outside diameter: 215 mm. Width: 40 mm per bearing. Series: 7200. Contact angle: 15°. Precision Class: P4 (ABEC 7). Single row per bearing, open on both faces, machined phenolic cage. Country of origin as recorded on this listing: Japan.

Decoding the designation

7224 = 72 series, 120 mm bore. C = 15° contact angle. T = machined phenolic cage rated to 120 °C. DUL = universally matchable duplex pair, light preload. P4 = ABEC 7 precision. Searchable forms: 7224CTDULP4, 7224-C-T-DUL-P4, 7224 C T DUL P4, 7224C, 7224CTRDULP4.

What these specs mean in practice

A 15° contact angle gives high speed capability and high radial stiffness, which is why it is the standard machine-tool spindle angle. The phenolic cage is light, quiet and oil-friendly at speed. P4 precision holds bore, outer ring and face runout tight, producing lower spindle vibration and closer tool location than a standard-class bearing.

Load ratings and speed

Basic dynamic load rating Cr: 250 kN (56,200 lbf) per bearing. Basic static load rating C0r: 192 kN (43,150 lbf) per bearing. Permissible axial load Pa: 132 kN. Limiting speed: 6,900 rpm on grease and 10,500 rpm on oil or oil-air. Effective load centre a: 42.4 mm. Mass: 5.42 kg (11.95 lb) per bearing.

Quantity and configuration

Two pieces ship, matching the DUL duplex designation. Rings are universally ground, so the pair mounts back-to-back, face-to-face or in tandem. Light preload as supplied: 1,395 N with an axial rigidity of 170 N/µm in a DB or DF pair.

Fitting notes

Shaft abutment diameter da: 132 mm minimum. Housing abutment diameters Da 203 mm and Db 208 mm maximum. Shaft and housing fillet radii ra 2 mm and rb 1 mm maximum. Chamfer dimensions r 2.1 mm and r1 1.1 mm minimum. Recommended grease charge: 29 g per bearing. As a preloaded matched pair the bearings carry no running clearance, so the internal clearance field reads N/A.

Interchange guidance

Direct equivalents at the same 15° angle, P4 class and light preload: SKF 7224 CD/P4ADGA, Fafnir 2MM224WI DUL, RHP 7224CTRDULP4, FAG B7224C.T.P4S.UL. Related size: 7224A5 shares the 120 x 215 x 40 mm envelope at a 25° contact angle, which raises thrust capacity and lowers the speed ceiling, so it is a different part rather than a substitution.