71811 CD/P4QBCA
71800 Series Super Precision Angular Contact Ball Bearings
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Part No.
Part No.
71811 CD/P4QBCA
Basic Information
System of measurement
Metric
Weight
0.32 kg
Tolerance class
P4
Seal type
Open
For load direction
Angular Contact
Main Dimensions
Bore diameter
55 mm
Bore diameter tolerance
-0.004mm to 0
Outside diameter
72 mm
Outside diameter tolerance
-0.004mm to 0
Width
36 mm
Width tolerance
-0.2mm to 0
Contact angle
15 °
Ball & Washer Dimensions
Ball diameter
4.762 mm
Ball quantity
29
Performance
Temperature range
- 30°C to 110 °C
Radial dynamic load rating
6075 lbf
Radial static load rating
9675 lbf
Limiting speed
34 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
Extra light / Class A
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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71811 CD/P4QBCA Bearing Product Overview & Core Advantages
The 71811 CD/P4QBCA is a precision angular contact ball bearing designed for demanding applications requiring exceptional rotational accuracy and rigidity. This metric bearing is supplied as a Quadruplex Back-to-Back (QBC) matched set, delivering superior performance in handling combined loads (radial and axial). Its P4 tolerance class and extra light preload (Class A) ensure high running accuracy and minimal deflection, making it ideal for high-speed spindles and other precision machinery.
71811 CD/P4QBCA Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71811 | Basic bearing designation, indicating a precision angular contact ball bearing with a 55 mm bore. |
| CD | Contact angle of 15°. |
| P4 | Tolerance class P4, denoting very high dimensional and running accuracy. |
| QBCA | Quadruplex Back-to-Back (QBC) matched set with Extra Light Preload (Class A). This arrangement provides maximum rigidity and is optimized for high-speed operation. |
71811 CD/P4QBCA Bearing Structural Features & Performance Benefits
- High Rigidity & Load Capacity: The Quadruplex Back-to-Back (QBC) arrangement of four bearings creates an extremely rigid system capable of supporting significant combined radial and axial loads from both directions. This configuration is essential for applications where shaft displacement must be minimized.
- Precision & High-Speed Performance: Manufactured to P4 tolerance class with tight dimensional controls on the bore, outside diameter, and width. The phenolic cage and 15° contact angle contribute to low friction and stable operation at the high limiting speed of 34,000 rpm.
- Optimized for Preload: The extra light preload (Class A) eliminates internal clearance, enhancing shaft positioning accuracy and system stiffness without generating excessive heat, which is critical for high-speed applications.
- Durable Construction: Components made from chrome steel for both rings and balls ensure high fatigue life and durability under demanding operating conditions.
71811 CD/P4QBCA Bearing Typical Application Areas
- Machine Tool Spindles: High-speed milling, grinding, and turning centers requiring extreme precision and rigidity.
- Precision Grinding Spindles
- High-Frequency Motors
- Industrial Pumps and Compressors
- Aerospace & Defense Positioning Systems
