71930 CD/P4AQBCD
71900 Series Super Precision Angular Contact Ball Bearings
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71930 CD/P4AQBCD Bearing Product Overview & Core Advantages
The 71930 CD/P4AQBCD is a precision angular contact ball bearing designed for the most demanding industrial applications. This quadruplex back-to-back (QBC) matched set delivers exceptional system rigidity and can accommodate combined radial and axial loads simultaneously. Manufactured to P4A tolerance class and featuring a heavy preload (Class D), it is engineered for high-precision, high-stability scenarios such as machine tool spindles, where minimal deflection and superior rotational accuracy are paramount. Its optimized internal geometry and phenolic cage contribute to outstanding high-speed performance.
71930 CD/P4AQBCD Bearing Model Code Explained, Specifications & Naming Convention
| Code Segment | Technical Meaning |
|---|---|
| 71930 | Basic bearing designation, indicating a high-precision angular contact bearing series with a 150 mm bore. |
| C | Designates a 15° contact angle, optimized for high-speed applications requiring high rigidity. |
| D | Indicates the application of a Heavy Preload (Class D) for maximum system stiffness. |
| /P4A | Specifies the tolerance class P4A, denoting extremely tight dimensional and running accuracy for precision machinery. |
| QBC | Denotes the bearing is supplied as part of a Quadruplex Back-to-Back matched set of 4 bearings. |
| D (at the end) | Further specifies the universal matching characteristic of the bearings within the pre-matched set. |
71930 CD/P4AQBCD Bearing Structural Features & Performance Benefits
- Exceptional Rigidity and Load Capacity: The quadruplex back-to-back arrangement creates an extremely rigid bearing system capable of withstanding heavy combined loads (radial and axial) and resisting moment loads. This configuration is critical for applications requiring minimal shaft deflection.
- Precision High-Speed Operation: The 15° contact angle and phenolic cage are optimized for high-speed performance, reducing friction and centrifugal forces. This allows the bearing to achieve a high limiting speed of 11,000 rpm.
- Superior Running Accuracy: Manufactured to P4A tolerance class with very tight bore, outside diameter, and width tolerances, this bearing ensures smooth, quiet, and vibration-free operation, which is essential for the surface finish quality in machining applications.
- Optimized Internal Design: The bearing utilizes 23 high-grade chrome steel balls of 19.05 mm diameter, providing a high dynamic load rating of 67,950 lbf and a static load rating of 117,000 lbf for long service life under demanding conditions.
71930 CD/P4AQBCD Bearing Typical Application Areas
This high-precision, high-rigidity bearing set is ideally suited for applications where extreme accuracy and stability are non-negotiable. Key industries and machinery include:
- Machine Tool Spindles: High-speed milling, grinding, and turning centers.
- Precision Grinding Spindles: Internal and external grinding machines.
- High-Frequency Motor Spindles: Used in PCB drilling and precision engraving.
- Industrial Pumps and Compressors: For applications requiring high shaft rigidity and precision.
