NSKNN4956KCC9P4Double Row Cylindrical Roller Bearing – 280 mm ID, 380 mm OD, 100 mm Width, 1:12 Tapered Bore, CC9 Clearance, P4 Precision

Product Description

What this part is

The NSK NN4956KCC9P4 is a double row cylindrical roller bearing from the NN49 super-precision series, built for machine tool spindles. Bore Diameter: 280 mm. Outside Diameter: 380 mm. Overall Width: 100 mm. Number Of Rows: 2. Rolling Elements: Cylindrical Roller. Bore Type: Tapered 1:12. Internal Clearance: CC9. Precision Class: ISO P4. Seal type: Open.

Decoding the designation

NN — double row cylindrical roller bearing with the guide ribs on the inner ring; the outer ring is a separable plain sleeve.

49 — dimension series 49, the thin cross-section spindle series.

56 — bore code, 56 x 5 = 280 mm.

K — 1:12 tapered bore.

CC9 — NSK radial internal clearance for tapered-bore precision cylindrical roller bearings.

P4 — ISO tolerance class 4, the super-precision grade.

What these specs mean in practice

Two rows of cylindrical rollers give very high radial load capacity and radial stiffness in a compact section. The tapered bore mounts directly on a tapered spindle journal, and drive-up along the taper sets the final running clearance. The P4 class holds radial runout to spindle-grade limits. The bearing carries radial load only and provides no axial location.

Quantity and configuration

Unit Quantity: 1 Pc. A single complete bearing, inner ring with roller sets and outer ring.

Interchange guidance

The equivalent envelope is 280 x 380 x 100 mm with a 1:12 taper. An NNU4956 places the ribs on the outer ring and is a different design. Harmonization Code: 8482.50.00.