HMK Cylindrical roller bearings are manufactured with precision forging and superfinishing grinding, consisting of inner ring, outer ring, cylindrical rollers and cage. Linear contact between rollers and raceways delivers superior radial load capacity and rigidity for medium & high-speed operation. 

Full standard range: NU, N, NJ, NUP, NF, NN, NNU compliant with ISO & GB standards. Precision grades P0/P5/P4 available, in stock & custom machining supported for diverse industrial harsh conditions including dusty, dry & medium-temperature working scenes.

NN Series Single Row Cylindrical Roller Bearings Product Details

1. Structure: Double row cylindrical rollers, inner ring with double ribs, outer ring without ribs. The outer ring can float axially and be separated freely.

2. Performance: Ultra-high radial stiffness, low deformation under heavy load, pure radial load bearing, excellent high-speed performance.

3. Advantage: Compact cross-section, high running accuracy, effectively compensate shaft thermal expansion during high-speed operation.

4. Application: Precision lathe spindle, grinding machine spindle, high-speed gearbox, industrial motor, precision automation equipment.

Main product Series

1. Single Row (NU/N/NJ/NUP/NF):  Most popular general type, bore size 15~500mm, widely used for electric motors, reducers, air compressors, pumps & conveyors.

2. Double Row (NN/NNU):  Double symmetrical rollers for boosted rigidity, cylindrical/taper bore optional, P4 precision for CNC machine spindle & high-precision gearboxes.

3. Full Complement (NCF/NJG): Cage-free dense rollers for extreme heavy load & low speed: mining crusher, metallurgical mill, crane wheel.

4. Custom Non-standard: Custom bore/OD, special clearance C2/C3/C4/C5, special steel, lubrication groove & hole per drawings.

Core Advantages

1. Ultra-high radial load capacity:  

Linear contact enlarges contact area, dynamic radial load 40% higher than same-size ball bearings; full-complement version gains extra 30% load rating against shock heavy loads.

2. Separable design for easy mounting:

Split inner & outer rings simplify installation and onsite maintenance, effectively cut machine downtime.

3. Extended service lifespan:  

Crown-modified roller ends avoid edge stress; AISI52100/GCr15 hardened to HRC60-65 for outstanding wear & fatigue resistance, 30% longer service life than inferior alternatives.

4. Various rib configurations for flexible fit: 

NU/N for floating end (free axial shift); NJ/NF for one-way axial load; NUP/NH for double-direction axial fixing as locating bearing.

5. 3 cage options: 

Stamped steel (cost-effective general use), machined brass (high-speed durable), PA66 nylon (low noise lightweight).

6. Wide working temperature: 

Standard range -30℃~120℃, nickel-plated/black oxide anti-corrosion surface treatment for dusty & slightly corrosive environment available.

Material & Production Process

• Ring & Roller Material: Premium GCr15/AISI52100 vacuum degassed bearing steel, carburizing & quenching heat treatment for stable metallurgical structure.

• Precision Machining: Raceway superfinishing & roller mirror grinding, dimension tolerance strictly follow ISO norms, clearance inspected piece by piece before delivery.

• Surface Finish: Standard black oxide, nickel plating & phosphating available for anti-rust requirement.

Main Applications

✅ General Machinery: Electric motors, gear reducers, vacuum pumps, centrifugal fans & compressors

✅ Mining & Metallurgy: Rolling mill, stone crusher, mineral conveyor, heavy-duty mine roller

✅ Construction Machinery: Loader, crane, excavator travel wheel, hydraulic motor

✅ Precision Equipment: CNC spindle, grinding machine, textile & plastic extruder

✅ Wind Power & Rail Transit: Wind turbine gearbox, railway transmission box, large industrial drive unit

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