Product Overview

The NMT 7012 ACE/HCP4ALDGA is a pre-assembled duplex universally matchable super-precision hybrid ceramic angular contact ball bearing set, comprising 2 rows of bearings precision-paired in a universal matchable (SU) configuration. With a total width of 36 mm (18 mm per row × 2), a 60 mm bore, and a 95 mm outer diameter, this set features a 25° contact angle (ACE type) and high-speed E-type design, combined with silicon nitride (Si₃N₄) hybrid ceramic rolling elements (HC) and a phenolic resin cage, factory-preset with Class A extra light preload (GA). It integrates ultra-high-speed performance, high load capacity, and flexible arrangement capability into a single package, accommodating radial and unidirectional axial loads simultaneously.

 

The bearing set offers a radial dynamic load rating of 25.314 kN (5,690 lbf) and a radial static load rating of 24.046 kN (5,405 lbf). The LDGA universal matchable suffix indicates that this set features universal matchable (SU) capability – any two sets of the same model can be directly paired without selective shimming or additional grinding. Users can freely configure them in back-to-back (<>), face-to-face (><), or tandem (>>) arrangements. Manufactured to the P4A super-precision tolerance class with hybrid ceramic technology and Class A extra light preload, the set achieves a limiting speed of 33,000 r/min. The operating temperature range is -30°C to 110°C.

 

Model Code Decoding – Understanding NMT 7012 ACE/HCP4ALDGA

Code Meaning

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

ACE 25° contact angle + High-speed E-type design – 25° contact angle provides superior axial rigidity; E-type offers higher speed capability and can accommodate heavier loads than equivalent B-type designs

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

P4A Super-precision tolerance class – dimensional accuracy in accordance with ISO tolerance class 4, running accuracy better than ISO tolerance class 4

L Annular groove with two lubrication holes and two annular grooves fitted with O-rings in the outer ring – suitable for direct oil-air lubrication

DGA Duplex General Arrangement – 2-bearing matched set with universal matchable (SU) capability, factory-preset Class A extra light preload

Core Value: DGA universal matchability means every NMT 7012 ACE/HCP4ALDGA bearing's end-face height difference and parallelism are tightly controlled, allowing any two bearings of the same model to be directly paired without selection or re-grinding. The E-type high-speed design offers higher speed capability and can accommodate heavier loads than equivalent B-type designs. HC hybrid ceramic technology drastically reduces centrifugal forces and frictional heat at high speeds. The L outer ring lubrication design facilitates oil-air lubrication directly to the rolling contact zone – these four elements work together to make this bearing set a high-performance yet flexible general-purpose precision bearing solution.

 

Core Performance Advantages

1. Hybrid Ceramic Technology – A Leap in High-Speed Performance

Silicon nitride (Si₃N₄) ceramic balls have only 60% the density of bearing steel – they are harder, lighter, and more durable than steel. At high speeds, they drastically reduce centrifugal forces and frictional heat, lowering heat generation, enabling maximum speed, low heat generation, and long lifespan. 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, extending bearing service life.

 

2. 25° Contact Angle (ACE Type) + High-Speed E-Type Design – Ultra-High Speed and Heavy Load Combined

The 25° contact angle delivers superior axial rigidity while maintaining ample radial capacity. The E-type high-speed design optimizes internal geometry and rolling element parameters, significantly reducing sliding friction and churning losses at high speeds. Compared to equivalent B-type high-speed bearings, the E-type design offers higher speed capability and can accommodate heavier loads. Combined with hybrid ceramic rolling elements and a phenolic resin cage, the set achieves a limiting speed of 33,000 r/min.

 

3. L Outer Ring Lubrication Design – Maximized Oil-Air Lubrication Efficiency

The L suffix indicates an annular groove with two lubrication holes and two annular grooves fitted with O-rings in the outer ring, enabling direct oil-air lubrication to reach the rolling contact zone for maximum lubrication and heat dissipation efficiency. This design ensures stable temperature performance even at 33,000 r/min ultra-high speeds, making it particularly suitable for oil-air lubrication systems.

 

4. Universal Matchable (DGA) – One Inventory, Infinite Arrangements

DGA universal matchability delivers outstanding value:

 

Simplified inventory: Stock a single model to cover DB (<>), DF (><), and DT (>>) pairing needs

 

On-site flexibility: Change arrangements during commissioning based on actual load directions

 

Easy maintenance: Replace individual bearings without replacing entire matched sets

 

No shims required: Install directly to achieve design preload

 

5. High Load Capacity – High Load in Compact Space

With optimized rolling element parameters (ball diameter 7.938 mm, 25 ceramic balls per bearing), it achieves an outstanding 25.314 kN (5,690 lbf) dynamic and 24.046 kN (5,405 lbf) static load rating within a compact 36 mm total width. The set weighs only 0.772 – 0.798 kg.

 

6. Class A Extra Light Preload – Ideal for High-Speed Precision Applications

Class A extra light preload provides "just-right" internal contact stiffness for high-speed spindles – eliminating internal clearance, reducing vibration and noise at high speeds, while avoiding excessive temperature rise from over-preloading. This ensures stable temperature performance even at 33,000 r/min limiting speeds.

 

7. P4A Super-Precision Grade – Micron-Level Accuracy

The P4A tolerance class (dimensional accuracy in accordance with ISO tolerance class 4, running accuracy better than ISO tolerance class 4) guarantees minimal radial runout and axial play. Bore and outside diameter tolerances are -0.004mm to 0, meeting stringent surface quality and dimensional consistency requirements. Operating temperature range is -30°C to 110°C.

 

8. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage (outer ring centred) provides excellent guidance accuracy and low friction at high speeds, contributing to reduced centrifugal forces, friction, and heat generation – a key factor in achieving the 33,000 r/min limiting speed.

 

9. Clear Performance Specifications

 

Parameter Value

Bore d 60 mm

Outer Diameter D 95 mm

Total Width B 36 mm (2×18 mm)

Contact Angle 25°

Radial Dynamic Load Rating 25.314 kN (5,690 lbf)

Radial Static Load Rating 24.046 kN (5,405 lbf)

Ball Diameter Dw 7.938 mm

Balls per Bearing 25

Limiting Speed 33,000 r/min

Ball Material Silicon Nitride (Si₃N₄)

Ring Material Chrome Steel

Cage Material Phenolic Resin

Seal Type Open

Tolerance Class P4A

Preload Class A (Extra Light)

Arrangement Universal Matchable (SU)

Bearings in Set 2

Weight 0.772 – 0.798 kg

Temperature Range -30°C to 110°C

Typical Applications

The NMT 7012 ACE/HCP4ALDGA, with its hybrid ceramic high-speed performance, E-type high-speed design, and universal matchable flexibility, covers an exceptionally wide range of high-end applications:

 

High-Speed Machine Tool Spindles – CNC machine tools, precision grinders, milling center spindles

 

High-Speed Electric Spindles – high-speed rotary units

 

Machining Center Spindles – vertical/horizontal spindle systems

 

Precision Rotary Tables – high-accuracy rotary positioning

 

Aerospace Components – gyroscopes, actuators, jet engine parts

 

Medical Equipment – high-speed dental drills and medical imaging devices

 

Semiconductor Manufacturing Equipment – precision wafer processing spindles

 

Industrial Robots – high-precision transmission mechanisms and rotary axes

 

Photovoltaic and Mold Industries – high-precision machining equipment

 

Gas Turbines and Centrifugal Separators – high-speed rotating machinery

 

Important Installation Notes

✅ This bearing set is universally matchable (DGA) – any two sets of the same model can be directly paired.

 

✅ This set is open design – select appropriate lubrication method based on application. To achieve the 33,000 r/min limiting speed, oil-air lubrication is strongly recommended, utilizing the L outer ring lubrication design for maximum efficiency.

 

✅ For paired installations, using bearings from the same production batch is recommended for optimal consistency.

 

⚠️ 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/OD tolerance -0.004mm to 0).

 

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

 

⚠️ Ensure the contact angle direction matches the intended load direction – incorrect orientation will eliminate load capacity.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies strict Japanese quality standards to every 7012 ACE/HCP4ALDGA bearing set – from ring material (high-purity chrome steel), ceramic balls (HIP silicon nitride), to superfinishing processes. End-face height difference, parallelism, and contact angle deviation of each bearing are tightly controlled to ensure universal matchability consistency across any two bearings of the same model. The combination of 25° contact angle (ACE type), E-type high-speed design, hybrid ceramic technology (HC), L outer ring lubrication design, P4A precision, Class A extra light preload, and universal matchable flexibility makes this bearing set the flagship general-purpose precision bearing solution in the NMT 7012 series – offering the perfect balance of high performance, efficient lubrication, and flexible arrangement.

 

Choose NMT 7012 ACE/HCP4ALDGA for:

 

✅ Hybrid ceramic technology – 33,000 r/min ultra-high-speed performance

 

✅ E-type high-speed design – high speed and heavy load combined

 

✅ L outer ring lubrication design – maximized oil-air lubrication efficiency

 

✅ Universal matchable – one inventory, infinite arrangements

 

✅ 25° contact angle – superior combined radial and axial load capacity

 

✅ Class A extra light preload – ideal for high-speed precision applications

 

✅ P4A super-precision running accuracy

 

✅ Steel rings + ceramic balls – high rigidity, high speed, cost-effectiveness

 

✅ Factory pre-matched – ready to install