71904 ACD/P4AQBCC
71900 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71904 ACD/P4AQBCC
Basic Information
System of measurement
Metric
Weight
0.14 kg
Tolerance class
P4A
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
20 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
37 mm
Outside diameter tolerance
-0.004mm to 0
Width
36 mm
Width tolerance
-0.2mm to 0
Contact angle
25 °
Ball & Washer Dimensions
Ball diameter
4.762 mm
Ball quantity
15
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
3398 lbf
Radial static load rating
2745 lbf
Limiting speed
100.5 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Quadruplex Back-to-Back (QBC)
Number of bearings in matched set
4
Universal matching bearing
No (Standard)
Preload
Moderate / Class C
Materials
Ring material
Chrome Steel
Ball material
Chrome Steel
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
Price available upon request.
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71904 ACD/P4AQBCC Bearing Product Overview & Core Advantages
The 71904 ACD/P4AQBCC is a super-precision angular contact ball bearing designed for the most demanding applications. Its core advantage lies in its matched quadruplex back-to-back (QBC) arrangement, which provides exceptional system rigidity and stability. This bearing is manufactured to an extremely tight P4A tolerance class, ensuring superior running accuracy. It is pre-lubricated and capable of handling combined radial and axial loads simultaneously, making it an ideal choice for high-speed, high-precision spindles and machinery where uncompromising performance is critical.
71904 ACD/P4AQBCC Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71904 | Basic bearing series and size designation (20mm bore, 37mm OD). |
| AC | Angular Contact design with a 25° contact angle. |
| D | Indicates a Moderate Preload (Class C) for optimal stiffness and speed performance. |
| /P4A | Denotes an ABEC 7 / ISO P4A super-precision tolerance class. |
| QBCC | Specifies a Quadruplex Back-to-Back (QBC) matched set of 4 bearings, supplied as a complete assembly. |
71904 ACD/P4AQBCC Bearing Structural Features & Performance Benefits
- Unmatched Rigidity and Stability: The quadruplex back-to-back (QBC) arrangement creates an extremely rigid bearing system that effectively resists complex moment loads and shaft deflection, crucial for maintaining precision under heavy cutting forces.
- High-Speed Capability: The lightweight and robust phenolic resin cage ensures stable operation and minimal centrifugal forces at the limiting speed of 100,500 rpm.
- Super-Precision Operation: Manufactured to P4A tolerance standards with tight dimensional control on bore, outside diameter, and width, resulting in extremely low runout and vibration for superior surface finishes.
- Optimized Load Capacity: The 25° contact angle is engineered to support significant combined loads, with a dynamic load rating of 3398 lbf and a static load rating of 2745 lbf.
- Ready-to-Install Performance: The set is supplied pre-lubricated and pre-matched, ensuring consistent performance right out of the box and simplifying the assembly process.
71904 ACD/P4AQBCC Bearing Typical Application Areas
This bearing is engineered for high-performance applications where extreme precision, speed, and rigidity are non-negotiable. Key industries and equipment include:
- High-Frequency CNC Machining Spindles
- Precision Grinding Spindles
- High-Speed Router and Milling Machine Spindles
- PCB Drilling and Milling Spindles
- Advanced Aerospace and Semiconductor Manufacturing Equipment
