Product Overview

The NMT 7012 CD/HCP4AQBCA is a pre-assembled quadruplex QBC matched super-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 72 mm (18 mm per row × 4), a 60 mm bore, and a 95 mm outer diameter, this set features a 15° contact angle (CD type) and D-type high-capacity design, combined with silicon nitride (Si₃N₄) hybrid ceramic rolling elements (HC) and a phenolic resin cage, factory-preset with extra light preload (Class A) , delivering ultimate bidirectional axial rigidity, overturning moment resistance, and ultra-high-speed precision rotational performance.

 

The bearing set offers a basic dynamic load rating of 101 – 106 kN and a static load rating of 132 – 140 kN. The QBC (tandem-back-to-back-tandem) configuration provides the highest system rigidity and bidirectional axial load capacity. Manufactured to the P4A super-precision tolerance class with hybrid ceramic technology and extra light preload, the set maintains micron-level rotational accuracy even at limiting speeds. The bore and outside diameters of the bearings are matched to within a maximum of one-third of the permitted diameter tolerance, ensuring highly uniform load distribution across all 4 rows. The set weighs 1.33 kg with a carbon footprint of 4.9 kg CO₂e.

 

Model Code Decoding – Understanding NMT 7012 CD/HCP4AQBCA

Code Meaning

7012 Basic series designation, 60 mm bore, 95 mm OD

CD 15° contact angle design – offers higher limiting speed and lower heat generation than 25° designs, ideal for ultra-high-speed precision operation

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

P4A Super-precision tolerance class – dimensional accuracy to ISO P4 class (ABEC 7), running accuracy superior to P4

QBC Quadruplex QBC arrangement (Quadruplex Back-to-Back-Cascade) – 4 bearings arranged in tandem-back-to-back-tandem (<<>>) configuration

A Extra light preload (Class A) – ideal for ultra-high-speed precision applications

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 bore and OD matching precision controlled within one-third of the allowable tolerance, and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. QBC Quadruplex Configuration – Ultimate System Rigidity and Bidirectional Axial 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 101 – 106 kN, static load rating 132 – 140 kN – nearly quadruple single-row capacity

 

2. 15° Contact Angle (CD Type) + D-Type High-Capacity Design – Ultra-High Speed and Ultimate Rigidity Combined

The 15° small contact angle generates less frictional heat at equivalent speeds, offering higher limiting speed potential than 25° contact angle designs. The D-type high-capacity design, with optimized rolling element parameters (ball diameter 11.112 mm, 19 ceramic balls per bearing), achieves an outstanding 101 – 106 kN dynamic and 132 – 140 kN static load rating within a compact 72 mm total width.

 

3. Hybrid Ceramic Technology – Speed and Durability Combined

Silicon nitride (Si₃N₄) 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. Preload force is 480 N with axial stiffness of 372 N/µm. 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, with bore and OD matching precision controlled within one-third of the allowable tolerance, ensuring highly uniform load distribution across all rows, preventing individual bearing overload, and significantly extending overall set service life. Operating temperature range is -30°C to 110°C.

 

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 60 mm

Outer Diameter D 95 mm

Total Width B 72 mm (4×18 mm)

Contact Angle 15°

Dynamic Load Rating 101 – 106 kN

Static Load Rating 132 – 140 kN

Ball Diameter Dw 11.112 mm

Balls per Bearing 19

Ball Material Silicon Nitride (Si₃N₄)

Ring Material Chrome Steel

Cage Material Phenolic

Tolerance Class P4A

Preload Class A (Extra Light)

Preload Force 480 N

Axial Stiffness 372 N/µm

Arrangement QBC (<<>>)

Bearings in Set 4

Weight 1.33 kg

Temperature Range -30°C to 110°C

Carbon Footprint 4.9 kg CO₂e

Typical Applications

The NMT 7012 CD/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 (QBC) – the 4 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model.

 

⚠️ 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, ensure shaft and housing fits comply with P4A grade requirements.

 

✅ Bore and OD matching precision is controlled within one-third of the allowable tolerance – ensure shaft and housing bore concentricity and straightness meet P4A grade requirements.

 

⚠️ Total width is 72 mm. Ensure sufficient axial installation space.

 

⚠️ 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, with bore and OD matching precision controlled within one-third of the allowable tolerance, ensuring load-sharing deviation between rows is minimized to an extremely small range. The 7012 CD/HCP4AQBCA delivers P4A accuracy, 15° contact angle ultra-high-speed performance, D-type high-capacity design, hybrid ceramic technology, and QBC quadruplex ultimate rigidity for unparalleled rotational support in your premier heavy-duty ultra-high-speed spindles.

 

Choose NMT 7012 CD/HCP4AQBCA for:

 

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

 

✅ 15° contact angle + D-type high capacity – ultra-high speed and ultimate rigidity combined

 

✅ Hybrid ceramic technology – speed and durability together

 

✅ Class A extra light preload – precision stiffness at speed limits (480 N / 372 N/µm)

 

✅ P4A super-precision running accuracy

 

✅ Factory pre-matched – matching precision within one-third of tolerance

 

✅ Dominates both heavy cutting and ultra-precision finishing