NMT Ltd.
Corporate Communications Department
Japan NMT N 1010 KTNHA/HC5SP Super-Precision Hybrid Ceramic Cylindrical Roller Bearing – The Ultimate Choice for High-Speed High-Precision Spindles
1 Model Information & Technical Parameters
Model:N 1010 KTNHA/HC5SP
Basic Dimensions
Parameter Value Unit
Bore diameter (d) 50 mm
Outside diameter (D) 80 mm
Width (B) 16 mm
Inner ring flange diameter (d₁) 61.3 mm
Outer ring raceway diameter (E) 72.5 mm
Fillet radius (r₁,₂ min.) 1.0 mm
Fillet radius (r₃,₄ min., tapered bore) 0.6 mm
Permissible axial displacement (s max.) 2 mm
Permissible axial displacement (s₁ max., TNHA cage) 1.5 mm
Bore type Tapered 1:12 —
Accuracy class HC5SP (Hybrid Ceramic + Super Precision) —
Performance Data
Parameter Value Unit
Dynamic load rating (C) 29.7 kN
Static load rating (C₀) 34.5 kN
Fatigue load limit (Pᵤ) 4.05 kN
Limiting speed – grease 28,000 r/min
Limiting speed – oil 32,000 r/min
Reference speed 20,000 r/min
Operating temperature range -30 ~ +150 (typical) °C
Bearing clearance C5 —
Technical Attributes
Attribute Detail
Bearing type Super-precision single row cylindrical roller bearing (hybrid ceramic)
Number of rows 1
Outer ring design Two flanges (integral ribs)
Inner ring design Flangeless
Roller material Silicon nitride (Si₃N₄) ceramic (HC5)
Cage material Glass fibre reinforced PEEK, outer ring centred (TNHA)
Ring material Bearing steel (chrome steel)
Seal type Open (no seals)
Bore type Tapered 1:12
Accuracy class HC5SP
Separable design Yes (inner and outer rings separable)
Logistics & Industry Codes
Parameter Value Unit
Net weight 0.23 kg
eClass code 23-05-08-03 (reference) —
UNSPSC code 31171504 (reference) —
Suffix Full Explanation
Suffix Meaning
N Single row cylindrical roller bearing, two flanges on inner ring, flangeless outer ring
10 Dimension series (N10 series)
10 Bore size code – 50 mm (10 × 5 = 50 mm)
K Tapered bore, taper 1:12
TNHA Glass fibre reinforced PEEK cage, outer ring centred (guided)
HC5 Rolling elements made of silicon nitride (Si₃N₄) ceramic
SP Super Precision class – dimensional accuracy approx. P5, running accuracy approx. P4
Important reminder: This model is a hybrid ceramic bearing with silicon nitride ceramic rollers, featuring electrical insulation properties to prevent electric erosion (critical for variable frequency motors and electric spindles). The tapered bore (1:12) requires a lock nut or withdrawal sleeve for mounting to achieve precise radial clearance adjustment. The bearing is open-type without seals and requires external lubrication and sealing protection based on operating conditions. The PEEK cage can withstand temperatures up to 260°C, suitable for extreme high-speed and high-temperature applications. The separable design allows independent mounting of inner and outer rings, facilitating assembly and maintenance.
2 Structure & Operating Characteristics
The NMT N 1010 KTNHA/HC5SP is a super-precision single row cylindrical roller bearing (N-type) , specifically developed as a hybrid ceramic bearing for ultra-high-speed, ultra-high-precision spindle applications. This bearing achieves an excellent balance between load capacity, speed and accuracy, representing the pinnacle of cylindrical roller bearing technology.
Single row roller design is the structural foundation. Single row cylindrical rollers with line contact between rollers and raceways provide high radial load capacity (dynamic load 29.7 kN) and low friction characteristics. Compared to double row bearings, the single row design allows higher speeds with less frictional heat generation, making it particularly suitable for ultra-high-speed rotation.
Silicon nitride (Si₃N₄) ceramic rollers (HC5 suffix) are the most revolutionary feature of this product. Compared to traditional steel rollers, ceramic rollers offer:
60% weight reduction: Ceramic density is only about 40% of steel, drastically reducing centrifugal forces
Lower thermal expansion: Ceramic thermal expansion coefficient is about 1/3 of steel, providing superior dimensional stability during operation
Significantly reduced frictional heat: Lower coefficient of friction between ceramic and steel, resulting in lower temperature rise
Electrical insulation: Ceramic rollers provide insulation against electric erosion (critical for variable frequency motors and electric spindles)
Higher limiting speeds: 28,000 r/min with grease, 32,000 r/min with oil
Extended service life: Ceramic materials offer higher hardness and superior wear resistance
Glass fibre reinforced PEEK cage (TNHA suffix) is another key technological feature. PEEK (polyetheretherketone) is a high-performance engineering plastic offering:
Excellent heat resistance: Continuous operation up to 260°C, far exceeding nylon cages
Superior dimensional stability: Glass fibre reinforcement significantly enhances rigidity and strength
Low friction and self-lubrication: Reduces friction with rollers and minimizes heat generation
Outer ring centred design: Cage guided by the outer ring, maintaining roller positioning accuracy at ultra-high speeds
Two-flange outer ring and flangeless inner ring (N-type design) allow the bearing to accommodate axial displacement in both directions, with maximum permissible axial displacement of 2 mm, effectively compensating for thermal expansion. The bearing itself does not carry axial loads; axial displacement is accommodated by the external structure.
Tapered bore (1:12) design enables precise radial clearance adjustment through axial advancement during mounting, critical for optimizing spindle system rigidity and accuracy.
HC5SP super-precision hybrid ceramic grade combines the dual advantages of HC5 (ceramic rollers) and SP (super precision), ensuring extremely high running accuracy and low vibration levels.
3 Core Performance Advantages
1. Ceramic rollers (HC5) – ultimate speed and extended service life. Silicon nitride ceramic rollers offer 60% weight reduction, thermal expansion coefficient only 1/3 of steel, and significantly reduced frictional heat. Grease limiting speed: 28,000 r/min; oil limiting speed: 32,000 r/min. Electrical insulation effectively prevents electric erosion, particularly suitable for variable frequency driven spindles.
2. PEEK cage (TNHA) – stability under extreme conditions. Glass fibre reinforced PEEK cage withstands temperatures up to 260°C with excellent dimensional stability. Outer ring centred design ensures roller positioning accuracy at ultra-high speeds.
3. Super-precision running accuracy (SP). Dimensional accuracy approx. P5, running accuracy approx. P4, ensuring ultra-low vibration, ultra-low noise and ultra-low heat generation to meet nano-level machining accuracy requirements.
4. High radial load capacity. Single row cylindrical roller line contact structure provides high radial load capacity (dynamic load 29.7 kN, static load 34.5 kN) while maintaining low friction characteristics.
5. Bidirectional axial displacement compensation. The two-flange outer ring and flangeless inner ring design allow the bearing to accommodate axial displacement in both directions during operation, with maximum permissible axial displacement of 2 mm, effectively compensating for thermal expansion.
6. Tapered bore mounting with precisely adjustable clearance. 1:12 tapered bore enables precise radial clearance adjustment through axial advancement during mounting, optimizing system rigidity.
7. Separable design for easy assembly and maintenance. Inner and outer rings can be mounted independently, greatly simplifying assembly and disassembly.
4 Typical Application Fields
4.1 Ultra-High-Speed Machine Tool Spindles
High-speed machining center spindles, high-speed milling spindles, high-speed grinding spindles – the combination of ceramic rollers and PEEK cage delivers exceptional performance above 30,000 r/min.
4.2 Precision Grinding Machines
External cylindrical grinder spindles, internal grinder spindles – high precision and high speed ensure mirror-quality machining.
4.3 Aerospace Engines and Gas Turbines
Aircraft engine main shafts, gas turbine rotor supports – high-temperature resistance and lightweight characteristics meet aerospace requirements.
4.4 High-Performance Automotive and Racing
High-performance automotive transmissions, racing gearboxes, high-speed drive units for electric vehicles.
4.5 Electric Motors and Generators
Variable frequency motors, high-speed generators, electric spindles – ceramic roller insulation effectively prevents electric erosion.
4.6 Precision Instruments and Testing Equipment
Ultra-high-precision measuring instruments, optical equipment rotary supports – extremely low vibration and high running accuracy meet precision measurement requirements.
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 (corresponding to C5 clearance class) is achieved. The separable design allows independent mounting of inner and outer rings.
5.3 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. C5 clearance is a larger clearance group, suitable for high-speed operation and applications with significant temperature variations.
5.4 Lubrication Maintenance
This model comes without pre-filled grease – lubricant must be added during installation based on operating conditions. Grease limiting speed is 28,000 r/min; oil limiting speed is 32,000 r/min. Ceramic rollers and PEEK cages have more stringent lubrication requirements – high-quality synthetic grease or specialized high-speed spindle oil is recommended. Open construction requires reliable sealing protection at the equipment level. Establish regular lubrication replenishment schedule; dry running is strictly forbidden.
5.5 Environmental Considerations
Typical operating temperature range: -30°C to +150°C (PEEK cage can withstand up to 260°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. Ceramic rollers are sensitive to impact loads – avoid subjecting the bearing to severe shocks beyond design limits.
6 Fault Identification
Common failure modes: Ceramic roller or steel raceway fatigue pitting (ceramic rollers have extremely high hardness – raceway damage typically occurs first), abnormal operating noise increase (ceramic roller fracture or cage wear), significant rotation resistance increase, excessive temperature rise, lubrication failure. If ceramic roller cracking or fracture occurs, repair and reuse are not allowed – replace the entire bearing assembly. Regularly monitor bearing temperature and vibration for early detection of abnormalities. Hybrid ceramic bearings require extremely high installation precision – improper mounting may cause localized overload and ceramic roller fracture.