Product Overview

The NMT 7009 CD/P4ADBC is a pre-assembled duplex back-to-back matched super-precision all-steel angular contact ball bearing set, comprising 2 rows of bearings precision-paired in a back-to-back (<>) configuration. With a total width of 32 mm (16 mm per row × 2), a 45 mm bore, and a 75 mm outer diameter, this set features a 15° contact angle (CD type) , D-type high-capacity design, all-steel rolling elements, and factory-preset Class C moderate preload, delivering superior system rigidity and bidirectional axial load capacity for high-speed spindles.

 

The bearing set offers a basic dynamic load rating of 46.8 kN and static load rating of 45 kN – several times the capacity of a single 7009 CD/P4A bearing. The back-to-back configuration provides maximum overturning moment rigidity and bidirectional axial load capacity, while the P4A super-precision tolerance class ensures micron-level rotational accuracy at high speeds. Maximum speed reaches 46,000 r/min under oil-air lubrication.

 

Model Code Decoding – Understanding NMT 7009 CD/P4ADBC

Code Meaning

7009 Basic series designation, 45 mm bore

CD 15° contact angle design – provides excellent balance between radial and axial load capacity

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

DB Duplex Back-to-Back – contact angle directions face outward (<>), providing maximum overturning rigidity

C Moderate preload (Class C) – optimal balance between high-speed capability and system rigidity

Note: Absence of "HC" suffix indicates all-steel rolling elements (not ceramic), offering superior cost-effectiveness and impact toughness while maintaining high rigidity.

 

Core Feature: The back-to-back (<> ) configuration extends the load action points outward, creating a maximum effective span that significantly enhances spindle resistance to bending moments. Class C moderate preload ensures sufficient contact stiffness at high speeds while avoiding excessive temperature rise from over-preloading. This is a non-universal matchable fixed set – the 2 bearings are factory end-face matched with preload setting and must not be interchanged or mixed with other bearings.

 

Core Performance Advantages

1. Back-to-Back Configuration – Maximum System Rigidity and Bidirectional Load Capacity

The back-to-back (<> ) arrangement orients the contact angles outward in opposite directions, maximizing the effective span and providing the highest overturning moment rigidity. Whether facing axial load direction changes, radial cutting force fluctuations, or bending moment impacts, this configuration delivers the most stable rotational support. With 46.8 kN dynamic and 45 kN static ratings, load capacity nearly triples compared to single-row bearings.

 

2. 15° Contact Angle – Excellent Balance of Speed and Load Capacity

The 15° small contact angle generates less frictional heat at equivalent speeds while providing an excellent balance between radial and axial load capacity. Combined with P4A super-precision tolerance and lightweight phenolic resin cage, the set maintains low temperature rise and high stability even at 46,000 r/min limiting speeds.

 

3. Class C Moderate Preload – The Golden Balance of Rigidity and Temperature

Class C moderate preload provides "just-right" internal contact stiffness. Compared to light preload (A/B), Class C offers higher system rigidity; compared to heavy preload (D), Class C maintains lower operating temperatures. This balance makes it the most versatile pairing choice, adaptable to the vast majority of high-speed precision spindle applications.

 

4. D-Type High-Capacity Design – High Load in Compact Space

By optimizing ball diameter (9.525 mm) and quantity (17 balls per bearing), the D-type design achieves an outstanding 46.8 kN dynamic and 45 kN static load rating within a 32 mm total width.

 

5. All-Steel Rolling Elements – High Rigidity, Impact Resistance, Cost-Effectiveness

Compared to hybrid ceramic versions, all-steel construction offers higher fracture toughness and impact resistance, making it more reliable under interrupted cutting and accidental overload conditions. All-steel bearings also offer significant cost advantages – a mature choice for high-volume industrial applications.

 

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

The P4A tolerance class guarantees minimal radial runout and axial play, meeting stringent surface quality and dimensional consistency requirements. Operating temperature range is -30°C to 110°C, adaptable to various industrial environments.

 

7. Lightweight Phenolic Resin Cage

The lightweight high-strength phenolic resin cage 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 46,000 r/min limiting speed.

 

8. Clear Performance Specifications

 

Parameter Value

Bore d 45 mm

Outer Diameter D 75 mm

Total Width B 32 mm (2×16 mm)

Contact Angle 15°

Dynamic Load Rating 46.8 kN

Static Load Rating 45 kN

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

Ball Material Chrome Steel

Ring Material Chrome Steel

Cage Material Phenolic

Tolerance Class P4A

Preload Class C (Moderate)

Arrangement Back-to-Back (<> ) DB

Number of Rows 2

Weight 0.462 – 0.47 kg

Carbon Footprint 1.66 kg CO₂e

Typical Applications

The NMT 7009 CD/P4ADBC is ideally suited for precision equipment demanding high system rigidity, bidirectional axial load capacity, and high-speed operation:

 

High-Speed Machining Center Spindles – vertical/horizontal milling and boring spindles

 

CNC Turning Centers – high-speed turning spindles (bidirectional cutting forces)

 

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

 

Aerospace Component Machining Equipment – high precision and reliability requirements

 

Industrial Robot Joints – high-precision transmission mechanisms

 

High-Speed Motors and Turbomachinery – various high-speed rotating machinery

 

Semiconductor Manufacturing Equipment – precision wafer processing spindles

 

Medical Equipment – high-speed rotary medical instruments

 

Important Installation Notes

⚠️ This is a non-universal matchable fixed set (DB) . The 2 bearings are supplied as one complete unit. Do not interchange or mix with other bearings of the same model.

 

⚠️ The back-to-back configuration (<> ) is directional. Ensure the contact angles face outward to achieve the expected overturning rigidity.

 

⚠️ This set comes with factory-preset Class C moderate preload. No additional preload adjustment is required during installation. However, shaft and housing fits must comply with NMT recommended tolerances.

 

⚠️ To achieve the 46,000 r/min limiting speed, oil-air lubrication is recommended. Maximum speed depends on lubrication, mounting fit, and heat dissipation conditions. Please consult NMT technical engineers for application-specific speed recommendations.

 

⚠️ The bearing set comes pre-lubricated from the factory – ready to install out of the box.

 

NMT Quality Commitment

Japan NMT (Enmutī) applies stringent end-face matching grinding and Class C moderate preload control to every DB back-to-back bearing set, ensuring load-sharing deviation between the two rows is minimized to an extremely small range. The 7009 CD/P4ADBC delivers P4A accuracy, D-type high-capacity design, 15° contact angle high-speed performance, and Class C moderate-preload rigidity for long-lasting, stable rotational support in your bidirectional high-speed spindles.

 

Choose NMT 7009 CD/P4ADBC for:

 

✅ Back-to-back configuration – maximum overturning rigidity

 

✅ 15° contact angle – excellent balance of speed and load capacity

 

✅ Class C moderate preload – optimal rigidity-temperature balance

 

✅ D-type high-capacity design – high load in compact space

 

✅ P4A super-precision running accuracy

 

✅ All-steel – high rigidity, impact resistance, cost-effectiveness

 

✅ Factory pre-matched – ready to install

 

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