71904 CD/HCPA9A
Hybrid Ceramic Super Precision Bearings
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Part No.
Part No.
71904 CD/HCPA9A
Basic Information
System of measurement
Metric
Weight
0.033 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
9 mm
Width tolerance
-0.2mm to 0
Contact angle
15 °
Ball & Washer Dimensions
Ball diameter
4.762 mm
Ball quantity
15
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
1361 lbf
Radial static load rating
720 lbf
Limiting speed
80 X 1000 rpm
Lubrication
Lubricated
Matched arrangement
Single
Number of bearings in matched set
2
Universal matching bearing
No (Standard)
Preload
Available
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
Price available upon request.
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71904 CD/HCPA9A Bearing Product Overview & Core Advantages
The 71904 CD/HCPA9A is a high-precision angular contact ball bearing engineered for applications demanding exceptional accuracy and performance. This single bearing features a 15° contact angle and is supplied with a preload, delivering superior rotational accuracy and system rigidity. Its compact design, with a 20 mm bore and 9 mm width, makes it ideal for space-constrained, high-speed applications such as precision spindles. The combination of a ceramic ball material and phenolic cage contributes to its high limiting speed of 80,000 rpm and reliable operation.
71904 CD/HCPA9A Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71904 | Basic bearing designation, indicating a metric, angular contact bearing with a 20mm bore and 37mm outside diameter. |
| CD | Indicates a duplex bearing arrangement with a specific preload. In this context, it refers to a matched set of two single bearings (as per specification) prepared for a back-to-back (DB) or face-to-face (DF) mounting configuration. |
| HC | Signifies the use of Hybrid Ceramic balls, which are lighter and harder than steel, reducing centrifugal force and enabling higher speeds. |
| PA9A | Denotes a high-precision tolerance class, equivalent to ABEC 7 or P4. This ensures extremely tight dimensional and running accuracy for critical applications. |
71904 CD/HCPA9A Bearing Structural Features & Performance Benefits
- Hybrid Ceramic Construction: The ceramic balls significantly reduce friction and wear, offer electrical insulation, and allow for operation at higher temperatures and speeds compared to all-steel bearings. This directly contributes to the high limiting speed.
- Phenolic Resin Cage: The phenolic cage is lightweight and possesses excellent slip characteristics, further supporting high-speed performance and providing good dimensional stability.
- Preloaded Design: The bearing is supplied with a preload, which eliminates internal clearance. This results in increased stiffness, precise shaft positioning, and reduced vibration and noise during operation.
- Precision Engineering: Manufactured to PA9A tolerance class, this bearing guarantees minimal runout and superior rotational accuracy, which is critical for machining quality and system performance.
- Optimized Load Capacity: The 15° contact angle provides an excellent balance, enabling the bearing to handle significant combined loads (radial and axial) simultaneously.
71904 CD/HCPA9A Bearing Typical Application Areas
The 71904 CD/HCPA9A is designed for high-performance machinery where precision, speed, and rigidity are paramount. Key application areas include:
- High-Frequency CNC Spindles for milling, grinding, and drilling
- Precision Machine Tooling and high-speed machining centers
- High-Speed Motors and servo drives
- Aerospace & Defense Instrumentation
- Medical & Dental Equipment spindles
- Semiconductor Manufacturing Equipment
