1 Complete Model, Dimensions, Loads & Technical Parameters

Full Model: 7003 ACD/P4ADBC

Model Code Explanation

7003: Base specification of 70 series precision angular contact bearing; ACD: 25° contact angle, D-type high-load two-point contact raceway geometry; P4A: P4A ultra-precision tolerance grade; DBC: Duplex Back-to-Back, factory preset back-to-back matched set with medium preload. Two bearings are precisely selected at factory, and the matching layout cannot be modified arbitrarily.

Standard Dimension Parameters

Bore d: 17 mm

Outer diameter D: 35 mm

Width B: 20 mm

Contact angle: 25 °

Load Performance Data

Basic dynamic load rating Cr: 10.6 kN

Basic static load rating C0r: 6.2 kN

Speed note: Contact SKF to obtain technical data of achievable operating speed

Full Product Attributes

Contact style: standard two-point contact

Row: 2 rows (duplex matched unit)

Race structure: integrated inner ring, integrated outer ring

Internal design: D-type high-load optimized design

Universal matched bearing: unavailable (fixed factory matching)

Matching arrangement: back-to-back <>

Quantity of bearings in set: 2 units

Preload / clearance specification: medium preload

Tolerance class: P4A precision grade

Material: bearing steel

Coating: uncoated

Seal: open type without seals

Pre-filled lubricant: none, lubrication configured on demand

Indicative carbon footprint for new product: 0.28 kg CO₂e

Net weight: 0.075 kg

eClass code: 23-05-08-04

UNSPSC code: 31171531

Speed note: Actual operating speed is affected by lubrication, heat dissipation, continuous load and assembly coaxiality. Confirm reference limiting speed with SKF before formal selection.

2 Structure & Operating Characteristics

Japan NMT 7003 ACD/P4ADBC is a D-type duplex precision angular contact bearing of 70 series with 25° contact angle, pre-set as back-to-back <> arrangement with medium preload upon delivery. The 25° large contact angle delivers excellent axial load capacity to withstand combined radial and bidirectional axial loads. Optimized D-type raceway homogenizes contact stress distribution, reduces stress concentration and improves load capacity and running stability. Integrated inner and outer rings maintain stable rigidity and minimize assembly deformation to sustain high-precision rotation.

Back-to-back duplex arrangement provides wider effective support span and superior resistance to overturning moment, suitable for spindles under bending and overturning loads. Medium preload balances system rigidity and operating temperature rise, combining shaft stiffness and high-speed heat dissipation performance. Open seal-free design eliminates friction loss from sealing elements and maximizes speed potential. No pre-filled lubricant inside; equipment manufacturers can select grease or oil-air lubrication according to speed range and load conditions.

The matched bearing set is precisely calibrated at factory. Do not use separately or change assembly layout without authorization. Unauthorized modification will destroy preset preload, resulting in increased vibration, precision degradation and shortened service life.

3 Core Performance Advantages

1. Factory Pre-Matched Back-to-Back Duplex Set: Two bearings precision-selected, eliminating on-site lapping and directly adapting to back-to-back support structure assembly.

2. 25° Large Contact Angle & D-Type High-Load Raceway: Strong axial load capacity, balanced contact stress, raising load limit and service life.

3. Standard Medium Preload Class: Balances support rigidity and heat generation, satisfying both machining accuracy and continuous high-speed operation.

4. Excellent Anti-Overturning Moment Capacity: Back-to-back layout widens support distance, ideal for spindles subjected to lateral force and bending moment.

5. P4A Ultra-Precision Grade: Strict control over radial and axial runout to maintain long-term high-precision rotation.

6. Integrated Bearing Steel Rings: High mechanical strength, good thermal stability and balanced wear resistance for continuous operation of precision machinery.

7. Open Seal-Free Construction: No extra friction loss to fully realize high-speed performance, compatible with advanced lubrication solutions such as oil-air lubrication.

4 Typical Application Scenarios

4.1 Precision Machine Tool Spindles: Small CNC engraving & milling spindles, precision grinding spindles, support units for medium & small high-speed machining centers.

4.2 Automated Heavy-Duty Precision Rotary Mechanisms: Precision heavy-duty indexing turntables, heavy-load joints of industrial robots, precision rotary support shafts for semiconductor equipment.

4.3 High-Precision Inspection & Optical Equipment: Rotary spindles of large image measuring instruments, heavy-duty rotary shafts of optical scanning platforms, precision mechanical test fixtures.

4.4 High-End Precision Light Industry Equipment: Spindles of precision high-speed textile machinery, transmission support components for medium & small precision medical devices.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A high-precision duplex matched bearings must be installed in dust-free clean environment. Remove burrs, dust and metal debris on shaft journals, housing bores and spacer mating surfaces. Thermal mounting is preferred. Direct impact on raceways, rolling elements and working surfaces is prohibited. Use the complete matched set; avoid mixing split bearings with other batches. Control interference fit properly: excessive interference leads to sharp temperature rise; insufficient interference causes outer ring creep and damages preload stability.

5.2 Matching Structure & Preload Instructions

This model is factory fixed as back-to-back <> duplex configuration with medium preload. Do not convert to face-to-face or tandem arrangement without approval. Back-to-back layout features wider support span and stronger resistance to overturning moment, suitable for spindles with lateral force and bending moment.

Preload value is precisely calibrated at factory. Do not grind spacers to adjust preload class. Re-evaluate bearing type and preload grade if load and speed conditions change significantly.

5.3 Lubrication Matching Solutions

No pre-filled lubricant inside bearing. Special high-speed grease can be adopted for low-speed continuous operation; oil-air circulating lubrication system is recommended for long-term high-speed, high-precision machining. Mixing different types or grades of lubricants is forbidden. Thoroughly clean bearing assembly before lubricant replacement.

5.4 Speed Parameter Note

Obtain reference limiting speed data directly from SKF. Reserve sufficient safety margin for continuous operation. Reduce operating speed under heavy load or poor heat dissipation to prevent premature fatigue failure.

6 Daily Maintenance & Fault Troubleshooting

Carry out low-speed no-load trial run after assembly, increase speed gradually, monitor vibration, noise and temperature rise. Formal operation can start only under stable working condition. Open design lacks built-in dust and coolant protection. External sealing must be installed at shaft end when dust, cutting fluid or moisture exists.

Replenish and replace lubricants periodically according to service cycle to maintain complete oil film on raceways. If continuous abnormal noise, precision decline or overheating occurs, sequentially inspect assembly interference, bearing mounting direction, foreign particle intrusion and lubrication failure. Avoid severe impact loads which cause permanent ring deformation.