1 Complete Model, Dimensions, Loads & Technical Parameters

Full Model: 7006 ACD/P4ADGA

Model Code Explanation

7006: Basic size of 70 series precision angular contact ball bearing;

ACD: 25° contact angle, D-type high-load optimized raceway geometry;

P4A: P4A ultra-precision tolerance grade;

DGA: Duplex universal matched set with factory ultra-light preload.

Standard Dimension Parameters

Bore d: 30 mm

Outer diameter D: 55 mm

Width B: 26 mm

Contact angle: 25 °

Performance Data

Basic dynamic load rating Cr: 22.1 kN

Basic static load rating C0r: 15.3 kN

Speed note: Contact SKF to obtain reference achievable rotational speed.

Full Product Attributes

Contact form: standard two-point contact

Number of bearings per set: 2

Ring structure: integrated inner ring and outer ring

Internal design: D-type high-load optimized design

Universal matching bearing: available for back-to-back (<>), face-to-face (><), tandem (>>) arrangement

Matching configuration: universal matching (DGA)

Quantity in set: 2 bearings

Preload / clearance: ultra-light preload

Tolerance class: P4A precision grade

Material: bearing steel

Coating: uncoated

Seal: open type without seals

Pre-filled lubricant: none, lubrication scheme configured on site

Indicative carbon footprint for new product: 0.81 kg CO₂e

Net weight: 0.219 kg

eClass code: 23-05-08-04

UNSPSC code: 31171531

Speed note: Actual permissible speed depends on lubrication, heat dissipation, continuous load, assembly coaxiality and preload. Request operating speed reference from SKF and reserve safety margin during selection.

2 Structure & Operating Characteristics

Japan NMT 7006 ACD/P4ADGA is a 25° D-type high-load duplex universal matched precision angular contact ball bearing with integrated bearing steel rings. D-type raceway expands effective rolling contact area and improves axial & combined load capacity. The 25° contact angle delivers higher axial rigidity than low-contact-angle variants and suits applications subjected to substantial axial force.

DGA denotes universal duplex matched set containing two dimensionally sorted bearings. The two bearings can be installed in back-to-back (DB), face-to-face (DF) or tandem (DT) layout without fixed sequence. Ultra-light preload is preset at factory, eliminating on-site spacer grinding for preload adjustment. Open non-sealed construction supports grease and oil-air lubrication; no grease is pre-filled inside bearings.

Ultra-light preload provides low vibration and moderate temperature rise at medium-high speed, balancing rotational accuracy and speed limit for medium-load precision spindles. Bearings from different sets cannot be intermixed for duplex arrangement.

3 Core Performance Advantages

1. D-Type High-Load Raceway + 25° Contact Angle: Superior load capacity and strong axial rigidity to withstand bidirectional axial and combined loads.

2. DGA Universal Duplex Set: Two sorted bearings allow flexible DB/DF/DT assembly without fixed order, simplifying mounting.

3. Factory-Set Ultra-Light Preload: Stable preload condition, less on-site machining, low vibration and balanced thermal behavior at high speed.

4. P4A Ultra-Precision Grade: Strict control over radial and axial runout for sustained long-term precision.

5. Integrated Bearing Steel Rings: High rigidity, good wear resistance and consistent fatigue life.

6. Open Seal-Free Structure: Eliminates seal friction, compatible with all mainstream lubrication systems and easy for oil-air lubrication layout.

7. Standardized Duplex Matching: Clear set marking; cross-set mixing prohibited to guarantee consistent matching accuracy.

4 Typical Application Scenarios

4.1 Precision Spindles for CNC Machine Tools: Medium-sized precision spindles for CNC milling machines, machining centers and mold engraving & milling machines.

4.2 Precision Feed Drive Axles for Machine Tools: Precision lead screw support shafts for lathes and grinders, high-speed rotary supports for linear drives.

4.3 Heavy-Duty Precision Rotary Mechanisms for Automation: Precision robot joints, heavy-duty rotary tables for automated inspection equipment.

4.4 High-Speed Precision Shafts for Textile & Printing: Spindles for high-speed printing machines, support units for precision winding equipment.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A high-precision duplex bearings must be assembled in dust-free clean environment. Remove all burrs, dust and contaminants from shaft journals, housings and spacers. Thermal mounting is preferred; direct impact on bearing faces and raceways is forbidden. Only bearings from the identical set can be paired; interchanging bearings between different sets is prohibited. Control interference fit properly; excessive interference increases temperature and disturbs factory preset preload.

5.2 Matching Layout & Preload Instructions

This DGA universal match supports DB back-to-back, DF face-to-face and DT tandem arrangement with factory ultra-light preload. Spacer modification is normally unnecessary under standard working conditions. Contact manufacturer for customized preload grades if required. Different layouts differ in rigidity and tilting moment resistance; select configuration according to equipment load condition.

5.3 Lubrication Matching Solutions

No pre-filled lubricant inside bearings. High-grade high-speed grease for medium-low speed; oil-air lubrication recommended for continuous medium-high speed operation. Do not mix different lubricant types. Maintain lubrication system regularly to prevent dust and cutting fluid ingress.

5.4 Speed Parameter Note

Request reference limiting speed data from SKF. Reserve 10%~20% safety speed margin for long-term continuous operation; reduce operating speed when axial load rises.

6 Daily Maintenance & Fault Troubleshooting

Carry out gradual low-speed running-in after assembly; continuously monitor vibration, noise and temperature. Loaded operation is permitted only under stable operating parameters. Open design lacks dust protection; reliable external shaft sealing must be implemented if cutting fluid or dust exists in working environment.

Monitor lubricant supply periodically to maintain stable oil film on raceways. In case of abnormal temperature rise, increasing vibration or periodic noise, sequentially check interference fit, installation orientation, coaxial accuracy, lubrication supply and contamination ingress. Avoid sudden shock loads which cause unbalanced preload.