1 Complete Model, Dimensions, Loads & Technical Parameters

Full Model: 7002 ACD/P4A

Model Code Explanation

7002: 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. Supplied as independent single-row bearing without factory matched set. Multiple bearings need to be selected and matched on site for multi-support shafting.

Standard Dimension Parameters

Bore d: 15 mm

Outer diameter D: 32 mm

Width B: 9 mm

Contact angle: 25 °

Load & Speed Performance Data

Basic dynamic load rating Cr: 4.94 kN

Basic static load rating C0r: 2.32 kN

Permissible speed for grease lubrication: 50 000 r/min

Permissible speed for oil-air lubrication: 75 000 r/min

Full Product Attributes

Contact style: standard two-point contact

Row: single row (independent single bearing)

Race structure: integrated inner ring, integrated outer ring

Internal design: D-type high-load optimized design

Universal matched bearing: not available (single unit supply)

Matching arrangement: none

Preload / clearance specification: not applicable (single row)

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: 0.11 kg CO₂e

Net weight: 0.03 kg

eClass code: 23-05-08-04

UNSPSC code: 31171531

Speed note: Listed speeds are reference limiting speeds. Actual operating speed is affected by lubrication, heat dissipation, load and assembly coaxiality. Oil-air lubrication is recommended for long-term operation near limiting speed.

2 Structure & Operating Characteristics

Japan NMT 7002 ACD/P4A is a D-type single-row precision angular contact bearing of 70 series with 25° contact angle. The 25° large contact angle provides excellent axial load capacity to withstand combined radial and unidirectional axial loads. Optimized D-type raceway improves contact stress distribution, enhancing load capacity and operational stability. Integrated inner and outer rings maintain stable rigidity and minimize deformation under assembly stress to preserve rotational accuracy.

Supplied as open single bearing without built-in seals to eliminate seal friction and maximize speed performance. Two reference speed ratings support two mainstream lubrication solutions. No pre-filled lubricant inside; equipment manufacturers can select grease or oil-air lubrication according to speed range and load conditions. Compact slim outline fits limited installation space of medium & small high-speed precision machinery.

Single-row angular contact bearings only sustain unidirectional axial force. To achieve bidirectional axial restraint and resist overturning moment, two or more bearings must be assembled in matched configurations including back-to-back, face-to-face or tandem arrangements.

3 Core Performance Advantages

1. 25° Large Contact Angle Geometry: Outstanding axial load capacity for combined radial + unidirectional axial load conditions.

2. D-Type High-Load Raceway Profile: Optimizes contact condition, reduces contact stress and increases load capacity & service life.

3. Dual Reference Limiting Speed: Separated rated speeds for grease and oil-air lubrication, facilitating lubrication system design.

4. P4A Ultra-Precision Grade: Strict control over radial and axial runout to sustain stable high-precision rotation at high speed.

5. Integrated Bearing Steel Rings: High mechanical strength, good thermal stability and balanced wear resistance.

6. Open Seal-Free Design: No extra friction loss to fully release high-speed performance potential.

7. Flexible Single Unit Supply: Free matching combinations based on shaft design to satisfy various support structures.

4 Typical Application Scenarios

4.1 Medium & Small High-Speed Precision Machining Spindles: PCB drilling spindles, small engraving & milling spindles, rotary units for micro grinding machines.

4.2 Automated Precision Rotary Components: Precision indexing mechanisms, miniature robot joints, high-speed rotary support shafts for semiconductor equipment.

4.3 Optical Inspection Instruments: Rotary shafts for image measuring equipment, high-speed rotary units on optical platforms, precision test fixtures.

4.4 Precision Light Industry Equipment: Rotary shafts of high-speed textile machinery, transmission supports for miniature precision medical devices.

5 Assembly Specifications & Usage Guidelines

5.1 Assembly Environment & Operation Standards

P4A high-precision single-row bearings shall be mounted in dust-free clean environment. Remove burrs, dust and metal debris on shaft journals and housing mating surfaces. Thermal mounting is preferred. Direct impact on raceways, rolling elements and working surfaces is prohibited. For multi-bearing matching, select bearings from the same batch to reduce accuracy deviation. Control interference fit properly: excessive interference causes higher operating temperature; insufficient interference leads to outer ring creep and abrasion.

5.2 Load & Matching Instructions

Single-row angular contact bearings can only carry unidirectional axial loads. If bidirectional axial force or overturning moment exists, two or more bearings must be installed in matched arrangement:

Back-to-back: stronger resistance to overturning moment, suitable for long support span;

Face-to-face: superior axial positioning accuracy for short-span locating shafts;

Tandem arrangement: maximized load capacity in one axial direction.

If preload is required, spacer dimensions shall be confirmed via mechanical calculation. Arbitrary machining of spacers is forbidden.

5.3 Lubrication Matching Solutions

No pre-filled lubricant inside bearing.

For speed ≤50 000 r/min: adopt special low-viscosity grease designed for high-speed operation;

For continuous speed above 50 000 r/min up to 75 000 r/min: oil-air circulating lubrication system is mandatory.

Mixing different types or grades of lubricants is forbidden. Thoroughly clean bearing before lubricant replacement.

5.4 Speed Parameter Note

50 000 r/min (grease lubrication) and 75 000 r/min (oil-air lubrication) are reference permissible speeds. Maintain sufficient safety margin for continuous operation. Reduce working speed under heavy load or poor heat dissipation to prevent premature fatigue failure.

6 Daily Maintenance & Fault Troubleshooting

Conduct low-speed no-load trial run after assembly, increase speed gradually, monitor vibration, noise and temperature rise. Formal operation can start only under stable condition. Open construction has no inherent dust or coolant protection. External sealing must be installed at shaft end if dust, cutting fluid or moisture exists.

Replenish and replace lubricants periodically according to working cycle to maintain complete oil film on raceways. If continuous abnormal noise, precision decline or overheating occurs, inspect assembly interference, matching layout, foreign particle intrusion and insufficient/failed lubrication in sequence. Avoid severe impact loads which cause permanent ring deformation.