Custom NU300 Series Cylindrical Roller Bearings Manufacturers, Factory

NU300 Series

The NU300 Series Cylindrical Roller Bearings are high-capacity radial bearings designed to manage significant loads in rotating machinery. Structurally, the NU design features two integral ribs on the outer ring and a smooth inner ring without ribs. This configuration allows for axial displacement of the shaft relative to the housing within specific limits, functioning effectively as a floating bearing. Manufactured from high-cleanliness chrome steel (GCr15), the rollers and raceways undergo logarithmic profile grinding to optimize stress distribution and minimize edge loading. The NU300 series is engineered for applications requiring high-speed rotation and precision, providing a separable design that simplifies mounting and dismounting during maintenance intervals.

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NU300 Series Cylindrical Roller Bearings

Core Technical Advantages

Radial Load Capacity: The line contact between rollers and raceways provides substantially higher radial load ratings compared to point-contact ball bearings of the same dimensions.
Axial Displacement Accommodation: The ribless inner ring permits the shaft to move axially, compensating for thermal expansion or contraction without inducing internal axial stress.
High-Speed Stability: Advanced cage designs and optimized internal geometry reduce centrifugal forces and heat generation during high-velocity operation.
Separable Components: The inner ring, outer ring, and roller-cage assembly can be installed independently, facilitating interference fits on both rings.

Key Product Characteristics

Technical Parameter	Specification Detail
Material	Through-hardened Chromium Steel (GCr15 / SAE 52100)
Rolling Element	Cylindrical Rollers with Logarithmic Profiles
Precision Class	Standard P0 / Precision P6 (ABEC-3)
Cage Variants	Pressed Steel (J) / Machined Brass (M) / Glass Fiber Reinforced Nylon (TVP)
Internal Clearance	C0 (Normal) / C3 / C4 (Large Clearance)
Temperature Range	-30°C to +120°C (Standard stabilization)

Primary Application Scenarios

Electric Motors & Generators: Providing stable radial support for large rotors while allowing for thermal shaft growth.
Industrial Gearboxes: Handling high input and output shaft loads in heavy-duty transmission systems and speed reducers.
Machine Tool Spindles: Ensuring high radial stiffness and precision in milling and grinding equipment.
Pumps and Compressors: Integrated into fluid handling systems where radial load density and reliability are critical for continuous operation.

Maintenance and Handling Guidelines

Storage and Preservation

Bearings should be stored in a temperature-controlled environment with relative humidity not exceeding 60%. Keep the units in their original vapor corrosion inhibitor (VCI) packaging. Horizontal storage is recommended for large-diameter NU300 bearings to prevent ring deformation under their own weight.

Installation and Usage Notes

Shaft and Housing Fit: Ensure that the ISO tolerance classes for shaft and housing seats match the bearing’s precision and clearance requirements to prevent excessive internal preload.
Lubrication Selection: Use high-pressure (EP) additives for heavy load applications. The choice between grease and oil lubrication should be based on the limiting speed (n) and operating temperature.
Mounting Force: Never apply mounting force through the rolling elements. Use appropriate induction heaters or mechanical sleeves to apply force directly to the ring being fitted.
Condition Monitoring: Regular analysis of vibration frequencies and housing temperatures can detect early signs of raceway fatigue or lubrication failure before catastrophic breakdown occurs.

Designation	Principal Dimensions(mm)					Basic Load Ratings(KN)		Limited Speed(rpm)		Weight
Designation	d	D	B	rs min	rs1min	Dynamic(Cr)	Static(Cor)	Grease	Oil	(kg)
NU304E	20	52	15	1.1	0.6	31.5	26.9	13000	15000	0.176
NU305E	25	62	17	1.1	1.1	41.5	37.5	11000	13000	0.275
NU306E	30	72	19	1.1	1.1	53	50	9300	11000	0.398
NU307E	35	80	21	1.5	1.1	71	71	8100	9600	0.545
NU308	40	90	23	1.5	1.5	58.5	57	8000	9400	0.658
NU308E	40	90	23	1.5	1.5	83	81.5	7200	8500	0.754
NU309	45	100	25	1.5	1.5	74	71	7200	8400	0.877
NU309E	45	100	25	1.5	1.5	97.5	98.5	6500	7600	0.996
NU310	50	110	27	2	2	87	86	6500	7700	1.14
NU310E	50	110	27	2	2	110	113	5900	6900	1.3
NU311	55	120	29	2	2	111	111	5900	7000	1.45
NU311E	55	120	29	2	2	137	143	5300	6300	1.65
NU312	60	130	31	2.1	2.1	124	126	5500	6500	1.8
NU312E	60	130	31	2.1	2.1	150	157	4900	5800	2.05
NU313	65	140	33	2.1	2.1	135	139	5100	6000	2.23
NU313E	65	140	33	2.1	2.1	181	191	4600	5400	2.54
NU314	70	150	35	2.1	2.1	158	168	4700	5500	2.71
NU314E	70	150	35	2.1	2.1	205	222	4200	5000	3.1
NU315	75	160	37	2.1	2.1	190	205	4400	5200	3.28
NU315E	75	160	37	2.1	2.1	240	263	4000	4700	3.74
NU316	80	170	39	2.1	2.1	190	207	4100	4800	3.86
NU316E	80	170	39	2.1	2.1	256	282	3700	4400	4.22
NU317	85	180	41	3	3	212	228	3900	4600	4.54
NU317E	85	180	41	3	3	291	330	3500	4100	4.81
NU318	90	190	43	3	3	240	265	3700	4300	5.3
NU318E	90	190	43	3	3	315	355	3300	3900	5.72
NU319	95	200	45	3	3	259	285	3400	4000	6.13
NU319E	95	200	45	3	3	335	385	3100	3600	6.62
NU320	100	215	47	3	3	299	335	3300	3800	7.49
NU320E	100	215	47	3	3	380	425	2900	3500	8.57
NU321	105	225	49	3	3	320	360	3100	3700	8.53
NU322	110	240	50	3	3	360	400	3000	3500	10
NU322E	110	240	50	3	3	450	525	2700	3100	11.1
NU324	120	260	55	3	3	450	510	2700	3200	12.8
NU324E	120	260	55	3	3	530	610	2400	2800	13.9
NU326	130	280	58	4	4	560	665	2500	2900	17.4
NU326E	130	280	58	4	4	615	735	2200	2600	19.4
NU328	140	300	62	4	4	615	745	2300	2700	21.2
NU328E	140	300	62	4	4	665	795	2100	2400	23.2
NU330	150	320	65	4	4	665	805	2100	2500	25.3
NU330E	150	320	65	4	4	760	920	1900	2300	28.4