1 Model Information & Technical Parameters

Model：N 1011 KPHA/HC5SP

 

Basic Dimensions

Parameter Value Unit

Bore diameter (d) 55 mm

Outside diameter (D) 90 mm

Width (B) 18 mm

Inner ring flange diameter (d₁) 68.2 mm

Outer ring raceway diameter (E) 81 mm

Chamfer dimension (r₁,₂ min.) 1.1 mm

Chamfer dimension (r₃,₄ min.) 0.6 mm

Permissible axial displacement (s max.) 2.5 mm

Bore diameter tolerance 0 to +0.015 mm

Outside diameter tolerance -0.010 to 0 mm

Width tolerance -0.15 to 0 mm

Bore type Tapered 1:12 —

Accuracy class HC5SP (Ceramic rollers + SP Super Precision) —

Radial internal clearance CN (Normal clearance) —

Performance Data

Parameter Value Unit

Dynamic load rating (C) 37.4 kN

Static load rating (C₀) 44 kN

Fatigue load limit (Pᵤ) 5.2 kN

Reference speed 24,000 r/min

Limiting speed – grease 24,000 r/min

Limiting speed – oil 30,000 r/min

Operating temperature range -30 ~ +110 °C

Shaft abutment diameter (da) 61.5 mm

Housing abutment diameter (Da) 82 – 83.5 mm

Technical Attributes

Attribute Detail

Bearing type Super-precision single row cylindrical roller bearing (hybrid ceramic)

Series N 10

Number of rows 1

Inner ring design Two flanges (integral ribs)

Outer ring design Flangeless

Roller material Silicon nitride (Si₃N₄) ceramic (HC5) 

Cage material Glass fibre reinforced PEEK, outer ring centred (PHA) 

Ring material Chrome steel

Seal type Open (no seals)

Bore type Tapered 1:12

Accuracy class HC5SP

Radial clearance CN (Normal clearance)

Separable design Yes (inner and outer rings separable)

Logistics & Industry Codes

Parameter Value Unit

Net weight 0.32 – 0.343 kg

eClass code 23-05-09-01 (reference) —

UNSPSC code 31171505 (reference) —

EAN 7316576761546 —

Suffix Full Explanation

Suffix Meaning

N Single row cylindrical roller bearing, two flanges on inner ring, flangeless outer ring

10 Dimension series (N10 series)

11 Bore size code – 55 mm (11 × 5 = 55 mm)

K Tapered bore, taper 1:12

PHA Glass fibre reinforced PEEK cage, outer ring centred

HC5 Rolling elements made of silicon nitride (Si₃N₄) ceramic

SP Super Precision class – dimensional accuracy approx. ISO 5, running accuracy approx. ISO 4

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 hydraulic nut 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. Operating temperature range: -30°C to +110°C. The separable design allows independent mounting of inner and outer rings, facilitating assembly and maintenance. The HC5SP accuracy class (HC5 ceramic rollers + SP super precision) represents one of the highest precision configurations for NMT super-precision bearings. The two-flange inner ring and flangeless outer ring (N-type) allow the bearing to accommodate axial displacement in both directions (max. 2.5 mm), effectively compensating for thermal expansion. This bearing type is commonly used as a floating bearing.

 

2 Structure & Operating Characteristics

The NMT N 1011 KPHA/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 37.4 kN, static load 44 kN) and low friction characteristics. Compared to full-complement cylindrical roller bearings, the caged design allows higher speeds with less frictional heat generation, making it particularly suitable for ultra-high-speed rotation (oil limiting speed up to 30,000 r/min).

 

Silicon nitride (Si₃N₄) ceramic rollers (HC5 suffix) are the most revolutionary feature of this product. Compared to traditional steel rollers, ceramic rollers offer:

 

Significant weight reduction: Ceramic density is far lower than 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: Up to 30,000 r/min with oil lubrication

 

Extended service life: Ceramic materials offer higher hardness and superior wear resistance

 

Glass fibre reinforced PEEK cage (PHA suffix) is another key technological feature. PEEK (polyetheretherketone) is a high-performance engineering plastic offering:

 

Excellent heat resistance: Far exceeding nylon cages in high-temperature performance

 

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 inner ring and flangeless outer ring (N-type design) allow the bearing to accommodate axial displacement in both directions, with maximum permissible axial displacement of 2.5 mm, effectively compensating for thermal expansion. The bearing itself does not carry axial loads; axial displacement is accommodated by the external structure. Therefore, N-type bearings are commonly used as floating bearings.

 

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) – dimensional accuracy approx. ISO 5, running accuracy approx. ISO 4 – ensuring extremely high running accuracy and ultra-low vibration levels.

 

3 Core Performance Advantages

1. Ceramic rollers (HC5) – ultimate speed and extended service life. Silicon nitride ceramic rollers offer significant weight reduction, thermal expansion coefficient far lower than steel, and significantly reduced frictional heat. Oil limiting speed reaches 30,000 r/min. Electrical insulation effectively prevents electric erosion, particularly suitable for variable frequency driven spindles.

 

2. PEEK cage (PHA) – stability at extreme speeds. Glass fibre reinforced PEEK cage offers excellent heat resistance and dimensional stability. Outer ring centred design ensures roller positioning accuracy at ultra-high speeds.

 

3. Super-precision running accuracy (SP). Dimensional accuracy approx. ISO 5, running accuracy approx. ISO 4, 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 37.4 kN, static load 44 kN) while maintaining low friction characteristics.

 

5. Bidirectional axial displacement compensation (max. 2.5 mm). The two-flange inner ring and flangeless outer ring design allow the bearing to accommodate axial displacement in both directions during operation, 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.

 

8. High-speed performance and low friction. Specifically designed for operations with extremely high speed requirements, ensuring minimal friction and heat generation.

 

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 at 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.

 

4.7 Industrial Gearboxes and Compressors

High-speed gearboxes, compressors, pumps – high rigidity and reliability ensure long-term stable operation.

 

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 CN normal clearance class) is achieved. The separable design allows independent mounting of inner and outer rings. Recommended shaft abutment diameter is 61.5 mm; housing abutment diameter is 82–83.5 mm.

 

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. Maximum permissible axial displacement is 2.5 mm – sufficient axial clearance must be预留 in the design.

 

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 24,000 r/min; oil limiting speed is 30,000 r/min. Ceramic rollers and PEEK cages have 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

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. Ceramic rollers are sensitive to impact loads – avoid subjecting the bearing to severe shocks beyond design limits. The bearing itself does not carry axial loads; axial displacement (max. 2.5 mm) is accommodated by the external structure.

 

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.