Product Overview

The NMT 7009 ACE/HCP4AQBCA is a pre-assembled quadruplex QBC matched ultra-precision hybrid ceramic angular contact ball bearing set, comprising 4 rows of bearings precision-paired in a tandem-back-to-back-tandem (<<>>) QBC configuration. With a total width of 64 mm (16 mm per row × 4), a 45 mm bore, and a 75 mm outer diameter, this set features a 25° contact angle (ACE type) , high-speed E-type design, silicon nitride (Si₃N₄) hybrid ceramic rolling elements, and factory-preset extra light preload (Class A) , delivering ultimate bidirectional axial rigidity, overturning moment resistance, and ultra-high-speed capability for the most demanding spindle systems.

 

The bearing set offers a basic dynamic load rating of 32.5 kN and static load rating of 32.5 kN – nearly triple the capacity of a single 7009 ACE/HCP4A bearing (12.1 kN / 8.15 kN). The QBC (Quadruplex Back-to-Back-Cascade) configuration provides the highest system rigidity and bidirectional axial load capacity, while the P4A super-precision tolerance class ensures micron-level rotational accuracy under extreme operating conditions. Maximum speed reaches 46,000 r/min under oil-air lubrication.

 

Model Code Decoding – Understanding NMT 7009 ACE/HCP4AQBCA

Code Meaning

7009 Basic series designation, 45 mm bore

ACE 25° contact angle + High-speed E-type design – balancing axial rigidity with ultra-high-speed performance; E-type optimizes ball geometry and cage structure for lower heat generation and higher limiting speeds

HC Hybrid ceramic – rolling elements made of bearing-grade silicon nitride (Si₃N₄)

P4A Super-precision tolerance class – dimensional accuracy P4, running accuracy exceeding P4

QBCA Quadruplex QBC matching (Quadruplex Back-to-Back-Cascade) – 4 bearings arranged in tandem-back-to-back-tandem (<<>>) configuration; A denotes extra light preload (Class A) 

Core Configuration Insight: The QBC (<<>>) configuration consists of 4 bearing rows – the center two in back-to-back (<> ) providing maximum overturning rigidity, with one tandem (>>) row on each side doubling unidirectional axial load capacity. This represents the highest rigidity and highest load capacity configuration available in angular contact bearing arrangements. This is a non-universal matchable fixed set – the 4 bearings are factory end-face matched with Class A extra light preload and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. QBC Quadruplex Configuration – Ultimate System Rigidity and Bidirectional Load Capacity

The QBC (<<>>) configuration combines the dual advantages of back-to-back (<> ) and tandem (>>) arrangements:

 

Center two rows back-to-back: Provides maximum overturning moment rigidity, effectively resisting bending and eccentric loads

 

One tandem row on each side: Doubles unidirectional axial load capacity on each side, with symmetric layout achieving perfect bidirectional axial load balance

 

Basic dynamic load rating 32.5 kN and static load rating 32.5 kN – nearly triple single-row capacity

 

2. 25° Contact Angle + High-Speed E-Type Design – Speed and Rigidity Perfected

The 25° contact angle delivers superior axial rigidity and radial load capacity. The E-type high-speed design optimizes ball diameter, count, and cage structure, significantly reducing sliding friction and churning losses at high speeds. Combined with hybrid ceramic rolling elements, the set maintains low temperature rise and high stability even at 46,000 r/min limiting speeds.

 

3. Hybrid Ceramic Technology – Speed and Durability Combined

Silicon nitride ceramic balls have only 60% the density of bearing steel, drastically reducing centrifugal forces and frictional heat at high speeds. Ceramic materials also offer lower thermal expansion coefficients and higher elastic modulus, effectively suppressing geometric deformation at high speeds while improving seizure resistance and lubrication-starvation tolerance, significantly extending maintenance intervals.

 

4. Extra Light Preload (Class A) – Precision Stiffness at Speed Limits

Class A extra light preload is the critical design balance for this QBC quadruplex set – with 4 rows providing exceptionally high structural rigidity, Class A preload ensures the preload force remains optimal, preventing temperature rise from over-preloading. This combination of high structural rigidity + low preload achieves the best possible balance between ultra-high speed and ultra-high rigidity.

 

5. P4A Super-Precision Grade – Micron-Level Spindle Accuracy

The P4A tolerance class guarantees minimal radial runout and axial play. All 4 bearings undergo factory precision end-face matching grinding, ensuring highly uniform load distribution across all rows, preventing individual bearing overload, and significantly extending overall set service life.

 

6. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage provides excellent guidance accuracy and low friction at high speeds, while its low mass further reduces centrifugal loads.

 

7. Clear Performance Specifications

 

Parameter Value

Bore d 45 mm

Outer Diameter D 75 mm

Total Width B 64 mm (4×16 mm)

Contact Angle 25°

Dynamic Load Rating 32.5 kN

Static Load Rating 32.5 kN

Speed (Oil-Air) 46,000 r/min

Speed (Grease) 29,000 r/min

Ball Material Silicon Nitride (Si₃N₄)

Ring Material High-purity Chrome Steel

Cage Material Phenolic Resin

Tolerance Class P4A

Weight 0.89 kg

Typical Applications

The NMT 7009 ACE/HCP4AQBCA is engineered for premium precision equipment demanding ultimate system rigidity, ultra-high speeds, and uncompromising accuracy:

 

Heavy-Duty Vertical/Horizontal Machining Center Spindles – powerful milling and heavy boring spindles

 

High-Rigidity 5-Axis Machining Centers – complex surface machining, aerospace structural component processing

 

Heavy-Duty CNC Turning Centers – large-depth, high-feed turning spindles

 

Precision Grinding Machine Wheel Spindles – high-accuracy internal/external grinding, jig grinders

 

Gear Cutting Machines – hobbing, shaping, milling, and grinding spindles

 

Large Mold Machining Centers – high-rigidity spindles for combined roughing and finishing

 

Aerospace Component Machining Equipment – high-speed heavy cutting of titanium and superalloys

 

Semiconductor Manufacturing Equipment – high-precision wafer processing spindles

 

Important Installation Notes

⚠️ This is a non-universal matchable fixed set (QBCA) . The 4 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model – this will destroy the precision end-face matching and preload settings.

 

⚠️ The QBC (<<>>) configuration is strictly directional. Installation must strictly follow NMT's assembly drawings to ensure correct contact angle orientation for each row. Incorrect orientation will completely eliminate load capacity.

 

⚠️ This set comes with factory-preset Class A extra light preload. No additional preload adjustment is required during installation. However, shaft and housing fits must strictly comply with NMT recommended tolerances to avoid preload abnormalities.

 

⚠️ Oil-air lubrication is strongly recommended to achieve the full high-speed potential (46,000 r/min). Grease lubrication limits speed to 29,000 r/min.

 

⚠️ Total width is 64 mm. Ensure sufficient axial installation space and that housing bore concentricity and straightness meet P4A grade requirements.

 

⚠️ Hybrid ceramic bearings are more sensitive to installation shock. Heat mounting or hydraulic installation methods are recommended – avoid impact on raceways or rolling elements.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies the most stringent end-face matching grinding and preload control to every QBC quadruplex bearing set. All 4 bearings undergo complete factory matching and full-parameter inspection, ensuring load-sharing deviation between rows is minimized to an extremely small range. The 7009 ACE/HCP4AQBCA delivers P4A accuracy, 25° contact angle high-speed performance, hybrid ceramic technology, and QBC quadruplex ultimate rigidity for unparalleled rotational support in your premier heavy-duty high-speed spindles.

 

Choose NMT 7009 ACE/HCP4AQBCA for:

 

✅ QBC quadruplex configuration – ultimate system rigidity and bidirectional load capacity

 

✅ 25° contact angle + E-type high-speed design – speed and rigidity combined

 

✅ Hybrid ceramic technology – speed and durability together

 

✅ Class A extra light preload – precision stiffness at speed limits

 

✅ P4A super-precision running accuracy

 

✅ Factory pre-matched – ready to install

 

✅ 46,000 r/min ultra-high-speed performance

 

✅ Dominates both heavy cutting and precision finishing