Cylindrical Roller Bearings

I. Type Codes (Core Structure)

Single row

NU: Outer ring without ribs, inner ring with double ribs. Carries radial loads; permits bidirectional axial displacement (for floating end positions).

NJ: Outer ring with double ribs, inner ring with single rib. Supports radial loads plus unidirectional axial location.

NUP: Outer ring with double ribs, inner ring with single rib plus loose rib. Supports radial loads plus bidirectional axial location.

N: Inner ring without ribs, outer ring with double ribs. Functionally equivalent to NU; cannot sustain axial loads.

NF: Inner ring with double ribs, outer ring with single rib. Supports radial loads plus unidirectional axial loads.

Double row

NN: Inner ring with double ribs, outer ring without ribs. High radialload capacity; allows axial displacement.

NNU: Outer ring with double ribs, inner ring without ribs. Heavy duty, high rigidity; widely used for machine tool spindles.

Four row

FC / FCD: Mill specific bearings for extremely heavy radial loads, e.g. FC3045120.

II. Numerical Meaning of Part Number (GB/T 272)

Example: NU2210  Last 1 -2 digits (bore code): 10 → 10 × 5 = 50 mm (general range 20-480 mm); 00 = 10 mm, 01 = 12 mm, 02 = 15 mm, 03 = 17 mm. – 3rd digit from right (diameter series): 2 → light series; 1 = extra light, 3 = medium, 4 = heavy.  4th digit from right (width series): 2 → wide series; 0 = normal (often omitted), 1 = narrow, 3 = extra-wide.

III. Common Suffix Definitions

M: Solid brass cage;

EM: Reinforced brass cage.

C3: Radial clearance larger than normal group;

C4: Further increased clearance (high-speed / high-temperature applications).

K: Tapered bore (1:12 taper), mountable with adapter sleeve.

W33: Outer ring with lubrication groove and oil holes for convenient relubrication.

IV. Key Selection Guidelines

1. Heavy radial loads and high-speed operation: Choose NU / N type (floating end) or NJ / NUP type (fixed end).
2. Machine-tool spindles and heavy-duty service: Select NN / NNU double-row bearings for high rigidity and precision.
3. Rolling mills and heavy-duty machinery: Adopt FC / FCD four-row bearings for ultra-high load-carrying capacity.

Model	d(mm)	D(mm)	B(mm)	Cr(kN)	Cor(kN)	Grease (r/min)	Oil (r/min)	W(kg)
NU202E	15	35	11	23.4	21.2	14000	18000	0.047
NU203E	17	40	12	27.2	24.5	13000	17000	0.068
NU204E	20	47	14	25.8	24.0	12000	16000	0.117
NU205E	25	52	15	32.2	30.5	11000	14000	0.130
NU206E	30	62	16	44.0	36.5	9000	12000	0.200
NU207E	35	72	17	54.8	48.2	8000	10000	0.300
NU208E	40	80	18	61.5	53.0	7000	9000	0.370
NU209E	45	85	19	67.5	60.2	6300	8000	0.430
NU210E	50	90	20	73.2	68.0	6000	7500	0.480
NU304E	20	52	15	36.8	33.8	11000	14000	0.150
NU305E	25	62	17	48.5	42.0	9500	12000	0.240
NU306E	30	72	19	62.8	54.2	8000	10000	0.360
NU307E	35	80	21	74.2	63.8	7000	8500	0.470
NU308E	40	90	23	91.5	81.2	6300	7500	0.650
NU2204E	20	47	18	30.8	30.0	12000	16000	0.149
NU2205E	25	52	18	38.5	37.8	10000	13000	0.180
NU2206E	30	62	20	52.8	48.5	8500	11000	0.270
NU2207E	35	72	23	70.2	64.5	7500	9500	0.420