71904 ACD/HCPA9ADBC
Hybrid Ceramic Super Precision Bearings
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Part No.
Part No.
71904 ACD/HCPA9ADBC
Basic Information
System of measurement
Metric
Weight
0.066 kg
Tolerance class
PA9A
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
18 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
2106 lbf
Radial static load rating
1372 lbf
Limiting speed
100.5 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Duplex Back-to-Back (DB)
Number of bearings in matched set
2
Universal matching bearing
No (Standard)
Preload
Moderate / Class C
Materials
Ring material
Chrome Steel
Ball material
Ceramic
Cage material
Phenolic
Technical Drawings
No drawings available at the moment, will be launched soon
In Stock
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71904 ACD/HCPA9ADBC Bearing Product Overview & Core Advantages
The 71904 ACD/HCPA9ADBC is a precision angular contact ball bearing designed for demanding applications requiring high rigidity and exceptional rotational accuracy. This duplex back-to-back (DB) arrangement is preloaded to provide moderate preload (Class C), ensuring stable operation under combined radial and axial loads. Its construction with a phenolic cage and ceramic balls makes it an ideal solution for high-speed applications, offering superior performance in a compact design.
71904 ACD/HCPA9ADBC Bearing Model Code Explained, Specifications & Naming Convention
The model number 71904 ACD/HCPA9ADBC is decoded as follows:
- 71904: Basic bearing series, indicating a light series angular contact bearing with 20mm bore, 37mm OD.
- AC: Angular Contact design.
- D: Duplex (Two single bearings are paired).
- H: Identifies specific internal design and tolerances for the matched set.
- C: Moderate Preload (Class C).
- PA9A: High-Precision Tolerance Class, ensuring extremely tight dimensional and running accuracy.
- DB: Back-to-Back arrangement, providing high moment rigidity.
- C: Ceramic balls (Silicon Nitride), offering reduced weight, lower friction, and higher speed capability.
71904 ACD/HCPA9ADBC Bearing Structural Features & Performance Benefits
- High Rigidity & Stability: The duplex back-to-back (DB) arrangement with moderate preload creates a highly rigid bearing system that effectively resists moment loads and shaft deflection, crucial for precision machining and spindle applications.
- Superior High-Speed Performance: The combination of a lightweight phenolic cage and low-density ceramic balls significantly reduces centrifugal forces, enabling a high limiting speed of 100,500 rpm. This minimizes heat generation and ensures stable operation at extreme velocities.
- Enhanced Load Capacity: With a 25° contact angle, this bearing is optimized to carry substantial combined loads (radial and axial) simultaneously, making it suitable for applications with complex loading conditions.
- Precision & Longevity: Manufactured to PA9A tolerance class, it guarantees minimal runout and vibration. The open seal type allows for optimized lubrication management, while the ceramic balls provide excellent wear resistance and a longer operational life.
71904 ACD/HCPA9ADBC Bearing Typical Application Areas
This bearing is engineered for high-performance machinery where precision, speed, and rigidity are paramount. Key applications include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Robotics: Arm joints and high-accuracy positioning systems.
- High-Frequency Motors: Spindles for PCB drilling and dental handpieces.
- Aerospace & Defense Systems: Gyroscopes, radar systems, and auxiliary power units.
- Medical Equipment: Centrifuges and advanced imaging devices.
