NMT Ltd.
Corporate Communications Department
Japan NMT NN 3010 KTN/W33VQ497 Super-Precision Double Row Cylindrical Roller Bearing with W33 Lubrication Feature – The Premium Choice for High-Rigidity Spindles
1 Model Information & Technical Parameters
Model:NN 3010 KTN/W33VQ497
Basic Dimensions
Parameter Value Unit
Bore diameter (d) 50 mm
Outside diameter (D) 80 mm
Width (B) 23 mm
Inner ring flange diameter (d₁) 61.3 mm
Outer ring raceway diameter (E) 72.5 mm
Width of lubrication groove (b) 3.8 mm
Lubrication hole diameter (K) 2.0 mm
Chamfer dimension (r₁,₂ min.) 1.0 mm
Chamfer dimension (r₃,₄ min.) 0.6 mm
Permissible axial displacement (s max.) 1.5 mm
Bore type Tapered 1:12 —
Tolerance class SP —
Performance Data
Parameter Value Unit
Dynamic load rating (C) 52.8 kN
Static load rating (C₀) 73.5 kN
Fatigue load limit (Pᵤ) 8.5 kN
Limiting speed – grease 11,000 r/min
Limiting speed – oil-air 13,000 r/min
Reference grease quantity (Gref) 2.7 cm³
Axial static stiffness (guideline) 1,040 N/µm
Operating temperature range -30 ~ +110 °C
Bore diameter tolerance 0 ~ +0.012 mm
Outside diameter tolerance -0.009 ~ 0 mm
Width tolerance -0.12 ~ 0 mm
Technical Attributes
Attribute Detail
Bearing type Super-precision double row cylindrical roller bearing
Series NN 30
Number of rows 2
Inner ring design Three flanges (integral ribs)
Outer ring design Flangeless
Cage material PA66 nylon injection moulded cage, roller centred
Roller material Chrome steel
Ring material Chrome steel
Seal type Open (no seals)
Bore type Tapered 1:12
Tolerance class SP
Separable design Yes (inner and outer rings separable)
Logistics & Industry Codes
Parameter Value Unit
Net weight 0.383 kg
eClass code 23-05-09-01 —
UNSPSC code 31171505 —
Suffix Full Explanation
Suffix Meaning
NN Double row cylindrical roller bearing, high precision series
30 Dimension series (ISO series 30)
10 Bore size code – 50 mm (10 × 5 = 50 mm)
K Tapered bore, taper 1:12
TN PA66 nylon injection moulded cage, roller centred
W33 Annular lubrication groove and three lubrication holes in the outer ring
VQ497 Quality and tolerances other than standard
Important reminder: This model features a tapered bore (1:12) . During mounting, a lock nut or withdrawal sleeve is used to drive the bearing onto the tapered shaft journal, enabling precise adjustment of radial clearance. The W33 lubrication feature provides an annular groove and three lubrication holes in the outer ring, significantly improving lubrication performance. The bearing is open-type without seals and requires external lubrication and sealing protection based on actual operating conditions. Operating temperature range: -30°C to +110°C. The separable design allows independent mounting of inner and outer rings, facilitating assembly and maintenance. The VQ497 suffix represents specific quality and tolerance grade requirements. The three-flange inner ring and flangeless outer ring allow the bearing to accommodate axial displacement in both directions (max. 1.5 mm), effectively compensating for thermal expansion.
2 Structure & Operating Characteristics
The NMT NN 3010 KTN/W33VQ497 is a super-precision double row cylindrical roller bearing from the NN 30 series, specifically developed for high-precision, high-rigidity applications such as machine tool spindles. This series achieves a unique balance between load carrying capacity, rigidity and speed.
Double row roller design is the core structural feature. Two rows of rollers arranged in parallel distribute loads more evenly across a wider area, offering higher load capacity and rigidity compared to single row bearings. The line contact between cylindrical rollers and raceways provides high radial load capacity, enabling the bearing to accommodate heavy loads and impact loads while also supporting high-speed rotation.
Three-flange inner ring and flangeless outer ring design is another key feature. The inner ring features three integral ribs (flanges) while the outer ring has no flanges, allowing the bearing to accommodate axial displacement in both directions. In applications with significant thermal expansion such as machine tool spindles, thermal elongation of the shaft and housing can be compensated through internal axial displacement, with maximum permissible axial displacement of 1.5 mm.
W33 lubrication feature is an important differentiator of this model from standard versions. The W33 suffix indicates an annular lubrication groove and three evenly distributed lubrication holes in the outer ring. This design enables lubricant to reach the raceway area more effectively, significantly improving lubrication performance and extending bearing service life. For high-speed spindle applications, proper lubrication is critical to ensuring bearing performance and reliability.
VQ497 quality grade represents quality and tolerances other than standard, ensuring consistency and reliability in critical applications.
Separable design enables independent mounting of inner and outer rings, which is particularly convenient in interference fit applications – one ring can be mounted first, then the other assembled, greatly simplifying assembly and disassembly.
PA66 nylon injection moulded cage (TN suffix) ensures precise roller positioning and stability at high speeds. PA66 material offers excellent wear resistance and low friction characteristics, effectively reducing heat generation and energy consumption. The cage prevents cylindrical rollers from contacting each other, enabling controlled motion of rolling elements.
Tapered bore (1:12) design enables precise radial clearance or preload adjustment through axial advancement during mounting, critical for optimizing spindle system rigidity and accuracy.
3 Core Performance Advantages
1. Extremely high radial load capacity. Double row roller design and cylindrical roller line contact structure enable the bearing to withstand very high radial and impact loads. Dynamic load rating reaches 52.8 kN; static load rating reaches 73.5 kN.
2. Superior system rigidity. The unique double row compact configuration of the NN 30 series provides exceptionally high radial stiffness (axial static stiffness up to 1,040 N/µm), making it ideal for precision spindle systems.
3. W33 lubrication feature – improved lubrication and extended service life. The annular lubrication groove and three lubrication holes in the outer ring enable lubricant to reach the raceway area more effectively, significantly improving lubrication performance and extending bearing service life.
4. VQ497 quality grade – reliable assurance for demanding conditions. Quality and tolerances other than standard ensure consistency and reliability in critical applications.
5. Bidirectional axial displacement compensation. The three-flange inner ring and flangeless outer ring design allow the bearing to accommodate axial displacement in both directions during operation, with maximum permissible axial displacement of 1.5 mm, effectively compensating for thermal expansion.
6. Super-precision running accuracy. SP tolerance class ensures low vibration, low noise and low heat generation, meeting high-precision machining requirements.
7. Tapered bore mounting with precisely adjustable clearance. 1:12 tapered bore enables precise radial clearance or preload adjustment through axial advancement during mounting, optimizing system rigidity.
8. Separable design for easy assembly and maintenance. Inner and outer rings can be mounted independently, particularly suitable for complex assembly conditions requiring interference fit.
9. Low friction, high efficiency and extended service life. Advanced materials and manufacturing techniques ensure minimal friction, reduced heat generation and extended service life. PA66 cage effectively reduces friction and energy consumption.
4 Typical Application Fields
4.1 Machine Tool Spindles
Machining center spindles (horizontal and vertical), turning center spindles, milling spindles – the combination of high rigidity, high accuracy and high speed is a perfect match.
4.2 Precision Grinding Machines
External cylindrical grinder spindles, internal grinder spindles – extremely high radial load capacity and running accuracy ensure machining quality.
4.3 Aerospace Engines and Gas Turbines
Aircraft engine main shafts, gas turbine rotor supports – high strength and reliability meet aerospace requirements.
4.4 High-Performance Automotive and Racing
High-performance automotive transmissions, racing gearboxes, high-speed drive units.
4.5 Medical Equipment
MRI and other advanced imaging equipment rotating components – low friction and high running accuracy meet the stringent reliability requirements of medical devices.
4.6 Robotics and Automation Systems
High-precision positioning units, automation system rotary supports – high rigidity support ensures motion accuracy.
4.7 Textile Machinery and Printing Equipment
High-speed textile machinery, printing press roller supports – delivering stability and precision at high speeds.
5 Assembly Specifications & Usage Guidelines
5.1 Pre-installation Inspection
Verify model and specifications match design requirements. Inspect bearing appearance to ensure no damage, corrosion or foreign matter. Check shaft taper (1:12) and dimensional accuracy against design specifications. Prepare appropriate mounting tools such as lock nuts or hydraulic nuts.
5.2 Installation Procedure
This bearing features a tapered bore (1:12) . During mounting, the bearing must be driven onto the tapered shaft journal. Use a lock nut or hydraulic nut to apply axial advancement force, precisely adjusting radial clearance by controlling advancement distance. Never apply force through rolling elements or cage. Monitor radial clearance changes throughout installation until the target clearance value is achieved. The separable design allows independent mounting of inner and outer rings.
5.3 Using the W33 Lubrication Feature
This bearing features an annular lubrication groove and three lubrication holes (W33) in the outer ring. During installation, ensure that the lubrication channels in the housing align with the lubrication holes in the bearing outer ring for effective lubricant delivery. Lubrication hole diameter is 2 mm; lubrication groove width is 3.8 mm.
5.4 Clearance Adjustment Instructions
Radial clearance of tapered bore bearings decreases as axial advancement increases. During mounting, use feeler gauges or dial indicators to monitor clearance changes, ensuring clearance is adjusted to the design target. Maximum permissible axial displacement is 1.5 mm.
5.5 Lubrication Maintenance
This model comes without pre-filled grease – lubricant must be added during installation based on operating conditions. Grease limiting speed is 11,000 r/min; oil-air limiting speed is 13,000 r/min. Reference grease quantity is 2.7 cm³. The W33 lubrication feature enables lubricant to reach the raceway area more effectively through the outer ring lubrication holes. High-quality spindle grease or circulating oil is recommended. Open construction requires reliable sealing protection at the equipment level. Establish regular lubrication replenishment schedule; dry running is strictly forbidden.
5.6 Environmental Considerations
Operating temperature range: -30°C to +110°C. As this bearing is open construction, in dusty environments or coolant splash conditions, labyrinth seals or contact seals must be provided at the equipment level. The bearing itself does not carry axial loads; axial displacement (max. 1.5 mm) is accommodated by the external structure.
6 Fault Identification
Common failure modes: Roller or raceway fatigue pitting, abnormal operating noise increase, significant rotation resistance increase, excessive temperature rise, seizure caused by poor lubrication. Blocked W33 lubrication holes may lead to lubrication failure – regularly inspect lubrication channels for. If cage deformation or rolling element damage occurs, replace the entire bearing assembly – repair and reuse are not allowed. Regularly monitor bearing temperature and vibration for early detection of abnormalities.